Continuously variable transmission can be lubricated by supplying to them a composition of (a) an oil of lubricating viscosity; (b) a dispersant; and (c) a detergent. At least one of the dispersant (b) and the detergent (c) is a borated species, and the amount of boron present in the composition is sufficient to impart improved friction and anti-seizure properties to the composition when employed in said transmission.

The present invention relates to high-boron formulations suitable for use as fluids for continuously variable transmissions.
Continuously variable transmissions (CVT) represent a radical departure from conventional automatic transmissions. The push belt version of the CVT was invented by Dr. Hub Van Doorne, and since its introduction, many cars have been equipped with the push belt CVT system. CVT push belts are manufactured by Van Doorne""s Transmissie VB of Tilburg, the Netherlands. A more detailed description of such transmissions and belts and lubricants employed therein is found in European Patent Application 753 564, published Jan. 15, 1997, as well as references cited therein. In brief, a belt and pulley system is central to the operation of this type of transmission. The pulley system comprises a pair of pulleys with a V-shaped cross-section, each consisting of a moveable sheave, a fixed sheave, and a hydraulic cylinder. Between the pulleys runs , a belt, which consists of a set of metal elements held together by metal bands. In operation, the driving pulley pushes the belt to the driven pulley, thereby transferring power from the input to the output. The transmission drive ratio is controlled by opening or closing the moveable sheaves so that the belt rides lower or higher on the pulley faces. This manner of operation permits continuous adjustment of gear ratio between the input and output shafts.
It has become clear from commercial use of the CVT that the fluids used in the CVT are just as important as the mechanical design for satisfactory operation. The lubricant must fulfill several functions: to lubricate the metal belt in its contacts with the pulley assembly, the planetary and other gears, the wet-plate clutches, and the bearings; to cool the transmission; and to carry hydraulic signals and power. The hydraulic pressure controls the belt traction, transmission ratio, and clutch engagement. The lubricant must provide the appropriate degree of friction between the belt and pulley assembly, to avoid the problem of slippage on one hand, and binding on the other, all the while providing protection to the metal surfaces from pitting, scuffing, scratching, flaking, polishing, and other forms of wear. Accordingly, the fluid should maintain a relatively high coefficient of friction for metal/metal contact, as well as exhibiting a suitable degree of shear stability.
U.S. Pat. No. 5,759,964, Sumiejski, Jun. 2, 1998 discloses an antiwear enhancing composition for lubricants and functional fluids such as automatic transmission fluids. It comprises a boron-containing overbased material; a phosphorus acid, ester, or derivative thereof, and a borated epoxide or borated fatty acid ester of glycerol.
U.S. Pat. No. 4,948,522, Dunn et al., Aug. 14, 1990, discloses a dispersant additive package for marine diesel engines comprising an oil of lubricating viscosity, a borated ashless dispersant, and one or more overbased metal compounds.
U.S. Pat. No. 5,750,477, Sumiejski et al., May 12, 1998, which is equivalent to EP 0 753 564 referred to above, discloses a shear stable lubricating/functional fluid composition, comprising an oil of lubricating viscosity, 1-15% by weight of the metal salt of an organic acid, and 1-25% viscosity modifier, wherein the composition has certain defined viscosity. Other components in the additive package include a metal dialkyl dithiophosphate, sulfur containing friction modifiers, dialkyl phosphites, and fatty amides.
European Application 761 805, Mar. 12, 1997, discloses a lubricating/functional fluid which comprises an oil of lubricating viscosity, 2,5dimercapto-1,3,4-thiadiazole or a derivative thereof and an antifoam agent. The composition may include phosphoric acid. Friction modifiers are included in the compositions in the amounts of 0.1-10 weight percent and may be a single friction modifier or mixtures of two or more. Friction modifiers also include metal salts of fatty acids. Preferred cations are zinc, magnesium, calcium, and sodium and any other alkali, or alkaline earth metals may be used. The salts may be overbased by including an excess of cations per equivalent of amine [sic; acid?]. Zinc salts are added in amounts of 0.1-5 weight percent to provide antiwear protection. The zinc salts are normally added as zinc salts of phosphorodithioic acids.
U.S. Pat. No. 4,792,410, Dec. 20, 1988, Schwind et al., discloses a lubricant mixture suitable for a manual transmission fluid, comprising a boronated overbased alkali metal or alkaline earth metal salt, a friction modifier or mixture of friction modifiers such as e.g. fatty acid amides and borated derivatives, and an oil of lubricating viscosity. Other typical ingredients may be included.
The metal-metal coefficient of friction and the antiseizure properties of CVT fluids are important performance parameters for the effective application of continuously variable transmissions. It is generally known that formulations containing zinc salts such as primary zinc dihydrocarbyl dithiophosphates resist metal-metal seizure and maintain high metal-metal coefficients of friction at the CVT belt-pulley interface. It is, however, desirable to formulate CVT fluids with compositions similar to automatic transmission fluids (ATFs). ATFs are generally not formulated with zinc dihydrocarbyl dithiophosphates because of their low thermal and oxidative stability and their known problems with clutch incompatibility.
The present invention, therefore, solves the problem of providing a suitable CVT fluid with exceptional metal-metal friction and good antiseizure properties, preferably free from primary zinc dihydrocarbyl dithiophosphates, by means of including boronated detergents and/or dispersants. The amount of zinc dihydrocarbyl dithiophosphates in the fully formulated CVT fluid is therefore preferably less than 1 percent, more preferably less than 0.5 percent, 0.1 percent, or 0.05%. The most preferred compositions are substantially free from zinc dihydrocarbyl dithiophosphates, e.g, less than 0.01 percent.
The compositions of the present invention can be used as lubricating oils and greases useful in industrial applications and in automotive engines, transmissions and axles. These compositions are effective in a variety of applications including crankcase lubricating oils for spark-ignited and compression-ignited internal combustion engines, including automobile and truck engines, two-cycle engines, aviation piston engines, marine and low-load diesel engines, and the like. They are also useful as additives for traction fluids. Also, automatic transmission fluids, manual transmission fluids, transaxle lubricants, gear lubricants, metalworking lubricants, hydraulic fluids, and other lubricating oil and grease compositions can benefit from the incorporation of the compositions of this invention. The inventive functional fluids are particularly effective as automatic transmission fluids, particularly fluids for continuously variable transmissions, including push-belt type and toroidal traction drive transmissions.
The present invention provides formulations suitable for use as fluids for continuously variable transmissions, comprising:
(a) an oil of lubricating viscosity; and
(b) a dispersant; or
(c) a detergent; or mixtures of (b) and (c);
wherein at least one of the dispersant (b) and the detergent (c) is a borated species and wherein the amount of boron supplied to the formulation is sufficient to impart improved friction and anti-seizure properties to said formulation.
The present invention further provides a method for lubricating a continuously variable transmission, comprising imparting to said transmission the aforedescribed formulation.
Various preferred features and embodiments will be described below by way of non-limiting illustration.
The first component of the present invention is an oil of lubricating viscosity which is generally present in a major amount (i.e. an amount greater than 50% by weight). Generally, the oil of lubricating viscosity is present in an amount of greater than 80% by weight of the composition, typically at least 85%, preferably 90 to 95%. Such oil can be derived from a variety of sources, and includes natural and synthetic lubricating oils and mixtures thereof.
The natural oils useful in making the inventive lubricants and functional fluids include animal oils and vegetable oils (e.g., lard oil, castor oil) as well as mineral lubricating oils such as liquid petroleum oils and solvent treated or acid-treated mineral lubricating oils of the paraffinic, naphthenic or mixed paraffinic/naphthenic types which may be further refined by hydrocracking and hydrofinishing processes and are dewaxed. Oils of lubricating viscosity derived from coal or shale are also useful. Useful natural base oils may be those designated by the American Petroleum Institute (API) as Group I, II, or III oils. Group I oils contain  less than 90% saturates and/or  greater than 0.03% sulfur and have a viscosity index (VI) of xe2x89xa780. Group II oils contain xe2x89xa790% saturates, xe2x89xa60.03% sulfur, and have a VI xe2x89xa780. Group III oils are similar to group II but have a VI xe2x89xa7120.
Upon occasion, highly refined or hydrocracked natural oils have been referred to as xe2x80x9csyntheticxe2x80x9d oils. More commonly, however, synthetic lubricating oils are understood to include hydrocarbon oils and halo-substituted hydrocarbon oils such as polymerized and interpolymerized olefins (e.g., polybutylenes, polypropylenes, propylene-isobutylene copolymers, chlorinated polybutylenes); poly(1-hexenes), poly(1-octenes), poly(1-decenes), and mixtures thereof; alkyl-benzenes (e.g., dodecylbenzenes, tetradecylbenzenes, dinonylbenzenes, di-(2-ethylhexyl)-benzenes); polyphenyls (e.g., biphenyls, terphenyls, alkylated polyphenyls); alkylated diphenyl ethers and alkylated diphenyl sulfides and the derivatives, analogs and homologs thereof and the like. Polyalpha olefin oils are also referred to as API Group IV oils.
Alkylene oxide polymers and interpolymers and derivatives thereof where the terminal hydroxyl groups have been modified such as by esterification or etherification constitute another class of known synthetic lubricating oils that can be used. These are exemplified by the oils prepared through polymerization of ethylene oxide or propylene oxide, the alkyl and aryl ethers of these polyoxyalkylene polymers (e.g., methyl-polyisopropylene glycol ether having an average molecular weight of about 1000, diphenyl ether of polyethylene glycol having a molecular weight of 500-1000, or diethyl ether of polypropylene glycol having a molecular weight of 1000-1500) or mono- and polycarboxylic esters thereof, for example, the acetic acid esters, mixed C3-8 fatty acid esters, or the C13Oxo acid diester of tetraethylene glycol.
Another suitable class of synthetic lubricating oils that can be used comprises the esters of dicarboxylic acids (e.g., phthalic acid, succinic acid, alkyl succinic acids, alkenyl succinic acids, maleic acid, azelaic acid, suberic acid, sebacic acid, fumaric acid, adipic acid, linoleic acid dimer, malonic acid, alkyl malonic acids, or alkenyl malonic acids) with a variety of alcohols (e.g., butyl alcohol, hexyl alcohol, dodecyl alcohol, 2-ethylhexyl alcohol, ethylene glycol, diethylene glycol monoether, or propylene glycol) Specific examples of these esters include dibutyl adipate, di(2-ethylhexyl) sebacate, di-n-hexyl fumarate, dioctyl sebacate, diisooctyl azelate, diisodecyl azelate, dioctyl phthalate, didecyl phthalate, dieicosyl sebacate, the 2-ethylhexyl diester of linoleic acid dimer, the complex ester formed by reacting one mole of sebacic acid with two moles of tetraethylene glycol and two moles of 2-ethylhexanoic acid and the like.
Esters useful as synthetic oils also include those made from C5 to C12 monocarboxylic acids and polyols and polyol ethers such as neopentyl glycol, trimethylol propane, pentaerythritol, dipentaerythritol, or tripentaerythritol.
Silicon-based oils such as the polyalkyl-, polyaryl-, polyalkoxy-, or polyaryloxy-siloxane oils and silicate oils comprise another useful class of synthetic lubricants (e.g., tetraethyl silicate, tetraisopropyl silicate, tetra-(2-ethylhexyl)silicate, tetra-(4-methyl-hexyl)silicate, tetra-(p-tert-butylphenyl) silicate, hexyl-(4-methyl-2pentoxy)disiloxane, poly(methyl) siloxanes, poly(methylphenyl)siloxanes). Other synthetic lubricating oils include liquid esters of phosphorus-containing acids (e.g., tricresyl phosphate, trioctyl phosphate, diethyl ester of decane phosphonic acid), polymeric tetrahydrofurans and the like.
Another class of oils is known as traction oils, which are typically synthetic fluids containing a large fraction of highly branched or cycloaliphatic structures, i.e., cyclohexyl rings. Traction oils or traction fluids are described in detail, for example, in U.S. Pat. Nos. 3,411,369 and 4,704,490.
Unrefined, refined, and rerefined oils, either natural or synthetic (as well as mixtures of two or more of any of these) of the type disclosed hereinabove can be used in the lubricants of the present invention. Unrefined oils are those obtained directly from a natural or synthetic source without further purification treatment. For example, a shale oil obtained directly from retorting operations, a petroleum oil obtained directly from primary distillation or ester oil obtained directly from an esterification process and used without further treatment would be an unrefined oil. Refined oils are similar to the unrefined oils except they have been further treated in one or more purification steps to improve one or more properties. Many such purification techniques are known to those skilled in the art such as solvent extraction, secondary distillation, acid or base extraction, filtration, percolation, hydroprocessing, hydrocracking, and hydrotreating. Rerefined oils are obtained by processes similar to those used to obtain refined oils applied to refined oils which have been already used in service. Such rerefined oils are also known as reclaimed or reprocessed oils and often are additionally processed by techniques directed to removal of spent additives and oil breakdown products.
In one embodiment, the oil of lubricating viscosity is a poly-alpha-olefin (PAO). Typically, the poly-alpha-olefins are derived from monomers having from 4 to 30, or from 4 to 20, or from 6 to 16 carbon atoms. Examples of useful PAOs include those derived from 1-decene. These PAOs may have a viscosity from 2 to 150.
Preferred base oils include poly-xcex1-olefins such as oligomers of 1-decene. These synthetic base oils are hydrogenated resulting in an oil of stability against oxidation. The synthetic oils may encompass a single viscosity range or a mixture of high viscosity and low viscosity range oils so long as the mixture results in a viscosity which is consistent with the requirements set forth below. Also included as preferred base oils are highly hydrocracked and dewaxed oils. These petroleum oils are generally refined to give enhanced low temperature viscosity and antioxidation performance. Mixtures of synthetic oils with refined mineral oils may also be employed.
Another required component of the present invention is a dispersant. Dispersants include acylated amines, carboxylic esters, Mannich reaction products, hydrocarbyl substituted amines, and mixtures thereof.
The acylated amines include reaction products of one or more carboxylic acylating agent and one or more amine. The carboxylic acylating agents include C8-30 fatty acids, C14-20 isoaliphatic acids, C18-44 dimer acids, addition dicarboxylic acids, trimer acids, addition tricarboxylic acids, and hydrocarbyl substituted carboxylic acylating agents. Dimer acids are described in U.S. Pat. Nos. 2,482,760, 2,482,761, 2,731,481, 2,793,219, 2,964,545, 2,978,468, 3,157,681, and 3,256,304. The addition carboxylic acylating agents are addition (4+2 and 2+2) products of an unsaturated fatty acid with one or more unsaturated carboxylic reagents, which are described above. These acids are taught in U.S. Pat. No. 2,444,328. In another embodiment, the carboxylic acylating agent is a hydrocarbyl substituted carboxylic acylating agent. The hydrocarbyl substituted carboxylic acylating agents are prepared by a reaction of one or more of the above olefins or polyalkenes with one or more of the above unsaturated carboxylic reagents, such as maleic anhydride. The amines can be any of those described elsewhere herein, preferably a polyamine, such as an alkylenepolyamine or a condensed polyamine. Acylated amines, their intermediates and methods for preparing the same are described in U.S. Pat. Nos. 3,219,666; 4,234,435; 4,952,328; 4,938,881; 4,957,649; 4,904,401; and 5,053,152.
In another embodiment, the dispersant can also be a carboxylic ester. The carboxylic ester is prepared by reacting at least one or more of the above carboxylic acylating agents, preferably a hydrocarbyl substituted carboxylic acylating agent, with at least one organic hydroxy compound and optionally an amine. The hydroxy compound can be an alcohol or a hydroxy containing amine. In another embodiment, the carboxylic ester dispersant is prepared by reacting the acylating agent with at least one of the above-described hydroxyamines. The alcohols are described above. Preferred alcohols are the above polyhydric alcohols, such pentaerythritol.
The polyhydric alcohols can be esterified with monocarboxylic acids having from 2 to 30, or from 8 to 18 carbon atoms, provided that at least one hydroxyl group remains unesterified. Examples of monocarboxylic acids include acetic, propionic, butyric and above described fatty acids. Specific examples of these esterified polyhydric alcohols include sorbitol oleate, including mono- and dioleate, sorbitol stearate, including mono- and distearate, glycerol oleate, including glycerol mono-, di- and trioleate and erythritol octanoate.
The carboxylic ester dispersants can be prepared by any of several known methods. The method which is preferred because of convenience and the superior properties of the esters it produces, involves the reaction of the carboxylic acylating agents described above with one or more alcohol or phenol in ratios from 0.5 equivalent to 4 equivalents of hydroxy compound per equivalent of acylating agent. The preparation of useful carboxylic ester dispersant is described in U.S. Pat. Nos. 3,522,179 and 4,234,435.
The carboxylic ester dispersants can be further reacted with at least one of the above described amines and preferably at least one of the above described polyamines, such as a polyethylenepolyamine, condensed polyamine, or a heterocyclic amine, such as aminopropylmopholine. The amine is added in an amount sufficient to neutralize any non-esterified carboxyl groups. In one embodiment, the carboxylic ester dispersants are prepared by reacting from 1 to 2 equivalents, or from 1.0 to 1.8 equivalents of hydroxy compounds, and up to 0.3 equivalent, or from 0.02 to 0.25 equivalent of polyamine per equivalent of acylating agent. The carboxylic acid acylating agent can be reacted simultaneously with both the hydroxy compound and the amine. There is generally at least 0.01 equivalent of the alcohol and at least 0.01 equivalent of the amine although the total amount of equivalents of the combination should be at least 0.5 equivalent per equivalent of acylating agent. These carboxylic ester dispersant compositions are known in the art, and the preparation of a number of these derivatives is described in, for example, U.S. Pat. Nos. 3,957,854 and 4,234,435.
In another embodiment, the dispersant can also be a hydrocarbyl-substituted amine. These hydrocarbyl-substituted amines are well known to those skilled in the art. These amines, and methods of making them, are disclosed in U.S. Pat. Nos. 3,275,554; 3,438,757; 3,454,555; 3,565,804; 3,755,433; and 3,822,289. Typically, hydrocarbyl substituted amines are prepared by reacting olefins and olefin polymers, including the above polyalkenes and halogenated derivatives thereof, with amines (mono- or polyamines). The amines can be any of the amines described above, preferably an alkylenepolyamine. Examples of hydrocarbyl substituted amines include poly(propylene)amine; N,N-dimethyl-N-poly(ethylene/propylene)amine, (50:50 mole ratio of monomers); polybutene amine; N,N-di(hydroxyethyl)-N-polybutene amine; N-(2-hydroxypropyl)-N-polybutene amine; N-polybutene-aniline; N-polybutenemorpholine; N-poly(butene)ethylenediamine; N-poly(propylene)trimethylenediamine; N-poly(butene)diethylenetriamine; Nxe2x80x2,Nxe2x80x2-poly(butene)tetraethylenepentamine; N,N-dimethyl-Nxe2x80x2-poly(propylene)-1,3-propylenediamine and the like.
In another embodiment, the dispersant can also be a Mannich dispersant. Mannich dispersants are generally formed by the reaction of at least one aldehyde, such as formaldehyde and paraformaldehyde, at least one of the above described amines, preferably a polyamine, such as a polyalkylenepolyamine, and at least one alkyl substituted hydroxyaromatic compound. The amounts of the reagents is such that the molar ratio of hydroxyaromatic compound to formaldehyde to amine is in the range from (1:1:1) to (1:3:3). The hydroxyaromatic compound is generally an alkyl substituted hydroxyaromatic compound. This term includes the above described phenols. The hydroxyaromatic compounds are those substituted with at least one, and preferably not more than two, aliphatic or alicyclic groups having from 6 to 400, or from 30 to 300, or from 50 to 200 carbon atoms. These groups can be derived from one or more of the above described olefins or polyalkenes. In one embodiment, the hydroxyaromatic compound is a phenol substituted with an aliphatic or alicyclic hydrocarbon-based group having an {overscore (M)}n of 420 to 10,000. Mannich dispersants are described in the following U.S. Pat. No. 3,980,569; 3,877,899; and 4,454,059.
In one embodiment, the dispersant is a borated dispersant. Typically, the borated dispersant contains from 0.1% to 5%, or from 0.5% to 4%, or from 0.7% to 3% by weight boron. In one embodiment, the borated dispersant is a borated acylated amine, such as a borated succinimide dispersant. Borated dispersants are described in U.S. Pat. Nos. 3,000,916; 3,087,936; 3,254,025; 3,282,955; 3,313,727; 3,491,025; 3,533,945; 3,666,662, 4,925,983 and 5,883,057. Borated dispersants are prepared by reaction of one or more dispersants with one or more boron compounds.
Suitable boron compounds for preparing borated dispersants include various forms of boric acid (including metaboric acid, HBO2, orthoboric acid, H3BO3, and tetraboric acid, H2B4O7), boric oxide, boron trioxide, and alkyl borates of the formula (RO)xB(OH)y wherein x is 1 to 3 and y is 0 to 2, the sum of x and y being 3, and where R is an alkyl group containing 1 to 6 carbon atoms. In one embodiment, the boron compound is an alkali or mixed alkali metal and alkaline earth metal borate. These metal borates are generally a hydrated particulate metal borate which are known in the art. Alkali metal borates include mixed alkali and alkaline metal borates. These metal borates are available commercially. Representative patents disclosing suitable alkali and alkali metal and alkaline earth metal borates and their methods of manufacture include U.S. Pat. Nos. 3,997,454; 3,819,521; 3,853,772; 3,907,601; 3,997,454; and 4,089,790.
The dispersant can also be a mixture of one or more borated dispersants with one or more non-borated dispersants.
Dispersants can also be post-treated by reaction with any of a variety of agents besides borating agents. Among these are urea, thiourea, dimercaptothiadiazoles, carbon disulfide, aldehydes, ketones, carboxylic acids, hydrocarbon-substituted succinic anhydrides, nitrites, epoxides, and phosphorus compounds. References detailing such treatment are listed in U.S. Pat. No. 4,654,403.
The amount of the dispersant on an oil free basis in the fully formulated fluids of the present invention is preferably 0.1 or 0.2 to 6 or 10 percent by weight, preferably 0.3 or 0.5 to 3 or 5 percent, and more preferably 1 or 2 to 3 or 4 percent. The dispersant, when it is borated, will preferably contribute 50 to 3000 parts per million (ppm) boron, more preferably 80 to 1500 ppm, and still more preferably 150, 200, 250, or 500 ppm to 1200 ppm boron, to the fully formulated fluid.
Another required component of the present invention is a detergent, which is typically in the form of an overbased metal salt. Overbased materials are generally single phase, homogeneous Newtonian systems characterized by a metal content in excess of that which would be present for neutralization according to the stoichiometry of the metal and the particular acidic organic compound reacted with the metal. The overbased materials are most commonly prepared by reacting an acidic material (typically an inorganic acid or lower carboxylic acid, preferably carbon dioxide) with a mixture comprising an acidic organic compound, a reaction medium comprising at least one inert, organic solvent (such as mineral oil, naphtha, toluene, or xylene) for said acidic organic material, a stoichiometric excess of a metal base, and a promoter such as a phenol or alcohol. The detergent component of the present additive mixture can be one or more borated or non-borated overbased alkali metal or alkaline earth metal salts of a sulfonic acid, phenol, salicylic acid, glyoxylic acid, carboxylic acid, or phosphorus-containing acid, or mixtures thereof. The term xe2x80x9csalicylatexe2x80x9d is used herein, as commonly in the art, to preferably mean salts of hydrocarbyl-substituted salicylic acid.
Sulfonate salts are those having a substantially oleophilic character and which are formed from organic materials. Organic sulfonates are well known materials in the lubricant and detergent arts. The sulfonate compound should contain on average 10 to 40 carbon atoms, preferably 12 to 36 and more preferably 14 to 32 carbon atoms. Similarly, the phenates, salicylates, and carboxylates should have a substantially oleophilic character. While the carbon atoms can be either in an aromatic or paraffinic configuration, it is preferred that alkylated aromatics be used. While naphthalene based materials can be used, the preferred aromatic materials are based on benzene.
A highly preferred composition is a monosulfonated alkylated benzene, preferably the monoalkylated benzene. Typically, alkyl benzene fractions are obtained from still bottom sources and are mono- or di-alkylated. It is believed that the mono-alkylated aromatics are superior in overall properties.
It is desirable that a mixture of mono-alkylated aromatics be used to obtain the mono-alkylated salt (benzene sulfonate). Mixtures in which a substantial portion of the composition contains polymers of propylene as the source of the alkyl groups assist in the solubility of the salt in the transmission fluids of the present invention. The use of mono-functional (e.g., mono-sulfonated) materials avoids crosslinking of the molecules and possible precipitation of the salt from the lubricant.
The detergent is referred to as xe2x80x9coverbased.xe2x80x9d By overbasing, it is meant that a stoichiometric excess of the metal be present, beyond that required to neutralize the anion of the salt. The excess metal from overbasing has the effect of neutralizing acids which may build up in the lubricant. Another important advantages is that the overbased salt increases the dynamic coefficient of friction. The overbasing is generally done such that the metal ratio is at least 1.05:1, preferably 2:1 to 30:1, and most preferably 4:1 to 25:1. The metal ratio is the ratio of metal ions, on an equivalent basis, to the anionic portion of the overbased material.
Preferably the overbased material is in the form of a metal salt where the metal is selected from group II of the periodic table of elements. Preferably it is a calcium or magnesium salt.
Preferably the overbased material is a carbonated material. Carbonated overbased materials are those which the low molecular weight acidic material which is preferably used in the formation of the material is carbon dioxide. The preparation of overbased materials, including carbonated overbased materials, is well known and is described, in numerous United States patents including, for example, U.S. Pat. No. 3,766,067, McMillen.
Preferably the overbased material is a carbonated overbased calcium sulfonate or a carbonated overbased calcium salicylate.
The overbased material can be borated or non-borated, as described below. The overbased material (detergent) can also be a mixture of one or more borated detergents with one or more non-borated detergents. Borated overbased materials and their preparation are well known and are described in greater detail in European Patent Application 753,564, published Jan. 15, 1997 and in U.S. Pat. No. 4,792,410.
Boronating agents include those described above in reference to the borated dispersants. An alkali metal borate dispersion can be prepared by the following steps: a suitable reaction vessel is charged with an alkaline metal carbonate overbased metal sulfonate within an oleophilic reaction medium (typically the hydrocarbon medium employed to prepare the overbased metal sulfonate). Boric acid is then charged to the reaction vessel and the contents vigorously agitated. The reaction is typically conducted for a period of 0.5 to 7 hours, usually from 1 to 3 hours at a reaction temperature of 20xc2x0 C. to 200xc2x0 C., preferably from 20xc2x0 C. to 150xc2x0 C., and more preferably from 40xc2x0 C. to 125xc2x0 C. At the end of the reaction period, the temperature is typically raised to 100xc2x0 C. to 250xc2x0 C., preferably from 100xc2x0 C. to 150xc2x0 C. to strip the medium of any residual alcohol and water. The stripping can be done at atmosphere pressure or under reduced pressure of, e.g., 93 kPa to 1 kPa.
The detergent, when it is borated, will preferably contribute 50 to 3000 parts per million (ppm) boron, more preferably 80 to 1500 ppm, and still more preferably 150, 200, 250, or 500 ppm to 1200 ppm boron, to the fully formulated fluid.
The total amount of oil free detergent in the fully formulated fluid is preferably 0.1 to 10 percent by weight, more preferably 0.2 to 5 percent, and still more preferably 0.3 to 2.5 percent by weight. The desirable amount of overbased detergent is that which is suitable to impart a specific amount of basicity to the formulation, and for that reason relatively lower amounts of high TBN detergents will normally be used and relatively higher amounts of low TBN detergent will normally be used. When a 300 TBN calcium detergent is used, typical amounts on an oil free basis will be 0.1 to 2 percent, preferably 0.3 to 1 percent, more preferably 0.5 to 0.7 percent. When a 10 TBN calcium detergent is used, typical amounts on an oil free basis will be 0.5 to 10 percent, preferably 1 to 4 percent. The total amount of calcium detergent is typically an amount suitable to provide 150 to 5000 parts per million calcium to the composition, preferably 300 to 2500 ppm, more preferably 600 to 1250 ppm. If other metals than calcium are used, the amounts will be adjusted accordingly to provide a comparable level of basicity.
The amount of the boron additive is to be a sufficient level to provide friction and antiseizure properties similar to those achieved by the use of zinc dialkyldithiophosphates. The preferred total amount of boron present in the fully formulated composition is at least 130 or 200 ppm, preferably at least 250 ppm, more preferably 400 to 3300 or 2000 ppm, and even more preferably 600 or 700 to 1700 or 1300 ppm. The boron component can be supplied by use of a borated dispersant or by use of a borated detergent. Preferably both the detergent and dispersant are borated.
The compositions of the present invention will generally contain other additives commonly used for ATFs or fluids for CVTs.
One common component for ATFs or CVT fluids is a viscosity modifier, (xe2x80x9cVM,xe2x80x9d also referred to as a viscosity index improver). Viscosity modifiers are extremely well known in the art and most are commercially available. Hydrocarbon VMs include polybutenes, poly(ethylene ipropylene) copolymers, and polymers of styrene with butadiene or isoprene. Ester VMs include esters of styrene/maleic anhydride polymers, esters of styrene/maleic anhydride/acrylate terpolymers, and polymethacrylates. The acrylates are available from RohMax and from The Lubrizol Corporation; polybutenes from Ethyl Corporation and Lubrizol; ethylenelpropylene copolymers from Exxon and Texaco; polystyrene/isoprene polymers from Shell; styrene/maleic esters from Lubrizol, and styrene/butadiene polymers from BASF.
Preferred VMs include acrylate- or methacrylate-containing copolymers or copolymers of styrene and an ester of an unsaturated carboxylic acid such as styrene/maleic ester (typically prepared by esterification of a styrene/maleic anhydride copolymer). Preferably the viscosity modifier is a polymethacrylate viscosity modifier. Polymethacrylate viscosity modifiers are prepared from mixtures of methacrylate monomers having different alkyl groups. The alkyl groups may be either straight chain or branched chain groups containing from 1 to 18 carbon atoms. When a small amount of a nitrogen-containing monomer is copolymerized with alkyl methacrylates, dispersancy properties are also incorporated into the product. Thus, such a product has the multiple function of viscosity modification, pour point depressancy and dispersancy. Such products have been referred to in the art as dispersant-type viscosity modifiers or simply dispersant-viscosity modifiers. Vinyl pyridine, N-vinyl pyrrolidone and N,Nxe2x80x2-dimethylaminoethyl methacrylate are examples of nitrogen-containing monomers. Polyacrylates obtained from the polymerization or copolymerization of one or more alkyl acrylates also are useful as viscosity modifiers. It is preferred that the viscosity modifier of the present invention is a dispersant viscosity modifier.
Some of the nitrogen-containing dispersant viscosity modifiers of the present invention can be prepared by a process comprising reacting, in the presence of a free radical initiator,
(A) 55% to 99.9% by weight, preferably 75 to 99.5% by weight, more preferably 90 to 99%, often 80 to 99% by weight of one or more alkyl acrylate ester monomers containing from 1 to 24 carbon atoms in the ester alkyl group, wherein at least 50 mole % of the esters contain at least 6 carbon atoms, preferably at least 8 carbon atoms, in the ester alkyl group, and
(B) 0.1% to 45% by weight, preferably 0.5 to 25% by weight, often 0.5 to 20% or 0.5 to 10%, often 1% to 20%, more preferably 1 to 10%, and in one embodiment 1.5 to 8% by weight of at least one nitrogen-containing monomer selected from the group consisting of vinyl substituted nitrogen heterocyclic monomers, dialkylaminoalkyl acrylate monomers, dialkylaminoalkyl acrylamide monomers, N-tertiary alkyl acrylamides, and vinyl substituted amines, provided that the total of the percentages of (A) and (B) equals 100%. The reaction is optionally conducted also in the presence of a chain transfer agent.
In a preferred process, monomer (A), the free radical initiator, and the chain transfer agent, if any, are first combined to form a mixture, whereupon 10% to 80% of said mixture is mixed with monomer (B), heating 20% to 100%, often 20% to 80%, more often 30% to 60%, and in one preferred embodiment 100%, of the resulting mixture until an exotherm is noted, then, while maintaining reaction temperature, first adding the balance, if any, of the mixture of monomers (A) and (B) over 0.25 hour to 5 hours followed by addition over 0.25 to 5 hours of the remaining mixture of monomer (A) and initiator, and then optionally adding additional initiator as may be required, whereupon the reaction is continued to completion. Any combination of the foregoing ratios of reactants is useful provided the total percentages equals 100%.
In one embodiment the dispersant viscosity modifier is prepared by polymerizing 57.5 parts methyl methacrylate, 12.7 parts butyl methacrylate, 226.5 parts each of C9-11 methacrylate and C12-15 methacrylate, 114.8 parts C16-18 methacrylate and 11.7 parts N-(3-(dimethylamino)propyl) methacrylamide in a staged addition process. Details of the preparation of these and related polymers are found in European Patent Application 750,031, published Dec. 27, 1996.
The copolymers described above typically have a weight average molecular weight ({overscore (M)}w) of 10,000 to 500,000, more often 30,000 to 250,000, frequently 20,000 to 100,000 and polydispersity values ({overscore (M)}w/{overscore (M)}n) of 1.2 to 5. Molecular weights of polymers are determined using well-known methods described in the literature.
Normally the amount of VM will be 1 to 25 percent by weight of the composition; preferably the amount will be 2 to 20 percent by weight, and more preferably 5 to 15 percent by weight.
Another common component for ATFs and CVT fluids is a phosphorus compound. Most phosphorus compounds impart a measure of anti-wear performance to the composition.
The phosphorus compound can be a phosphorus acid or ester of the formula (R1X)(R2X)P(X)nXmR3 or a salt thereof, where each X is independently an oxygen atom or a sulfur atom, n is 0 or 1, m is 0 or 1, m+n is 1 or 2, and R1, R2, and R3 are hydrogen or hydrocarbyl groups. Preferably at least one of R1, R2, and R3 is a hydrocarbyl group, and preferably at least one is hydrogen. This component thus includes phosphorous and phosphoric acids, thiophosphorous and thiophosphoric acids, phosphite esters, phosphate esters, and thiophosphite and thiophosphate esters. The esters can be mono-, di- or tri-hydrocarbyl esters. It is noted that certain of these materials can exist in tautomeric forms, and that all such tautomers are intended to be encompassed by the above formula and included within the present invention. For example, phosphorous acid and certain phosphite esters can be written in at least two ways, (RO)2xe2x80x94PH(xe2x95x90O) and (RO)2xe2x80x94Pxe2x80x94OH, differing merely by the placement of the hydrogen. Each of these structures are intended to be encompassed by the present invention.
The phosphorus-containing acids can be at least one phosphate, phosphonate, phosphinate or phosphine oxide. These pentavalent phosphorus derivatives can be represented by the formula (R1O) (R2O)(R3O)Pxe2x95x90O wherein R1, R2 and R3 are independently hydrocarbyl groups, or hydrogen. The phosphorus-containing acid can be at least one phosphite, phosphonite, phosphinite or phosphine. These trivalent phosphorus derivatives can be represented by the formula (R1O)(R2O)(R3O)P wherein R1, R2 and R3 are independently hydrocarbyl groups. The total number of carbon atoms in R1, R2 and R3 in each of the above formulae should be sufficient to render the compound soluble in the medium. Generally, the total number of carbon atoms in R1, R2 and R3 is at least 8, and in one embodiment at least 12, and in one embodiment at least 16. There is no limit to the total number of carbon atoms in R1, R2 and R3 that is required, but a practical upper limit is 400 or 500 carbon atoms. In one embodiment, R1, R2 and R3 in each of the above formulae are independently hydrocarbyl groups of preferably 1 to 100 carbon atoms, or 1 to 50 carbon atoms, or 1 to 30 carbon atoms. Each R1, R2 and R3 can be the same as the other, although they may be different. Examples of useful R1, R2 and R3 groups include hydrogen, t-butyl, isobutyl, amyl, isooctyl, decyl, dodecyl, oleyl, C18 alkyl, eicosyl, 2-pentenyl, dodecenyl, phenyl, naphthyl, alkylphenyl, alkylnaphthyl, phenylalkyl, naphthylalkyl, alkylphenylalkyl, alkylnaphthylalkyl, and the like.
In another embodiment, the phosphorus acid is characterized by at least one direct carbon-to-phosphorus linkage such as those prepared by the treatment of an olefin polymer, such as one or more of the above polyalkenes (e.g., polyisobutene having a molecular weight of 1000) with a phosphorizing agent such as phosphorus trichloride, phosphorus heptasulfide, phosphorus pentasulfide, phosphorus trichloride and sulfur, white phosphorus and a sulfur halide, or phosphorothioic chloride.
It is preferred that at least two of the X atoms in the above structure are oxygen, so that the structure will be (R1O)(R2O)P(X)nXmR3, and more preferably (R1O)(R2O)P(X)nXmH. This structure can correspond, for example, to phosphoric acid when R1, R2, and R3 are hydrogen. Phosphoric acid exists as the acid itself, H3PO4 and other forms equivalent thereto such as pyrophosphoric acid and anhydrides of phosphoric acid, including 85% phosphoric acid (aqueous), which is the commonly available commercial grade material. The formula can also correspond to a mono- or dialkyl hydrogen phosphite (a phosphite ester) when one or both of R1 and R2 are alkyl respectively and R3 is hydrogen, or a trialkyl phosphite ester when each of R1, R2, and R3 is alkyl; in each case where n is zero, m is 1, and the remaining X is O. The structure will correspond to phosphoric acid or a related material when n and m are each 1; for example, it can be a phosphate ester such as a mono-, di- or trialkyl monothiophosphate when one of the X atoms is sulfur and one, two, or three of R6, R7, and R8 are alkyl, respectively.
Phosphoric acid and phosphorus acid are well-known items of commerce. Thiophosphoric acids and thiophosphorous acids are likewise well known and are prepared by reaction of phosphorus compounds with elemental sulfur or other sulfur sources. Processes for preparing thiophosphorus acids are reported in detail in Organic Phosphorus Compounds., Vol. 5, pages 110-111, G. M. Kosolapoff et al., 1973.
The R1 and R2 groups can comprise a mixture of hydrocarbyl groups derived from commercial alcohols. Examples of some preferred monohydric alcohols and alcohol mixtures include the commercially available Alfol(trademark) alcohols marketed by Continental Oil Corporation. Alfol(trademark) 810, for instance, is a mixture containing alcohols consisting essentially of straight-chain primary alcohols having from 8 to 10 carbon atoms. Another commercially available alcohol mixture is Adol(trademark) 60 which comprises about 75% by weight of a straight-chain C22 primary alcohol, about 15% of a C20 primary alcohol, and about 8% of C18 and C24 alcohols. The Adol(trademark) alcohols are marketed by Ashland Chemical.
A variety of mixtures of monohydric fatty alcohols derived from naturally occurring triglycerides and ranging in chain length from C8 to C18 are available from Procter and Gamble Company. Another group of commercially available mixtures include the Neodol(trademark) products available from Shell Chemical Co. Other alcohols which can be used are lower molecular weight alcohols such as methanol, ethanol, propanol, isopropanol, normal butanol, isobutanol, tert-butanol, the pentanols, hexanols, heptanols, octanols (including 2-ethyl hexanol), nonanols, decanols, and mixtures thereof.
The dihydrocarbyl hydrogen phosphites of this invention can be prepared by techniques well known in the art, and many such phosphites are available commercially.
In one embodiment, the phosphorus-containing agent is a hydrocarbyl phosphate. The phosphate may be a mono-, di- or trihydrocarbyl phosphate. Hydrocarbyl phosphates can be prepared by reacting phosphorus acid or anhydride, preferably phosphorus pentoxide with an alcohol at a temperature of 30xc2x0 C. to 200xc2x0 C., preferably 80xc2x0 C. to 150xc2x0 C. The phosphorus acid is generally reacted with the alcohol in a ratio of about 1:3.5, preferably 1:3.
In another embodiment, the hydrocarbyl phosphate can be a hydrocarbyl thiophosphate. Thiophosphates may contain from one to three sulfur atoms, preferably one or two sulfur atoms. The thiophosphates may have the same hydrocarbyl group as described above. Thiophosphates are prepared by reacting one or more of the above-described phosphites with a sulfurizing agent including sulfur, sulfur halides, and sulfur containing compounds, such as sulfurized olefins, sulfurized fats, mercaptans and the like.
In another embodiment, the phosphorus compound can be a phosphorus-containing amide. Phosphorus-containing amides are generally prepared by reacting one of the above-described phosphorus acids such as a phosphoric, phosphonic, phosphinic, thiophosphoric, including dithiophosphoric as well as monothiophosphoric, thiophosphinic or thiophosphonic acids with an unsaturated amide, such as an acrylamide. Preferably the phosphorus acid is a dithiophosphorus acid prepared by reacting a phosphorus sulfide with an alcohol or phenol to form dihydrocarbyl dithiophosphoric acid. The hydrocarbyl groups may be those described above for hydrocarbyl phosphates.
The phosphorus-containing amides can be prepared by the reaction of a phosphorus-containing acid, preferably a dithiophosphoric acid, as described above with an acrylamide such as acrylamide, N,Nxe2x80x2-methylenebisacrylamide, methacrylamide, crotonamide, and the like. The reaction product from above may be further reacted with linking or coupling compounds, such as formaldehyde or paraformaldehyde to form coupled compounds.
The phosphorus compound can also be an amine salt of the foregoing acidic materials.
Examples of phosphorus-containing materials are phosphites and phosphates such as dibutyl phosphite, diphenylphosphite, triphenylphosphite, tricresylphosphate and triphenylthiophosphate.
The amount of the phosphorus containing compound or compounds in the fully formulated fluids of the present invention will typically be 0.05 to 5 percent by weight, preferably 0.1 to 2 percent, and more preferably 0.2 to 1 percent by weight. The amount of such compounds will depend to some extent on the specific compound, its molecular weight, phosphorus content, and activity. Typically the fully formulated fluids of the present invention will contain 150 to 1000 parts per million phosphorus, preferably 300 to 500 ppm phosphorus.
Another common component of ATFs and CVT fluids is one or more friction modifiers. Friction modifiers are very well known in the art, and the number and types of compounds are voluminous. In general, friction modifiers include metal salts of fatty acids, fatty phosphites, fatty acid amides, fatty epoxides and borated derivatives thereof, fatty amines, glycerol esters and their borated derivatives, alkoxylated fatty amines (including ethoxylated fatty amines such as diethoxylated tallowamine) and their borated derivatives, isostearic acid condensation products of polyamines such as tetraethylene pentamine, such condensates containing amide and imidazoline or imine functional groups, sulfurized olefins, sulfurized polyolefins, sulfurized fats, and sulfurized fatty acids. They can also be suspended molybdenum disulfide, dialkyl or diaryl dithiophosphate molybdates or alkyl or dialkyl dithiocarbamate molybdates where the molybdenum is oxydisulfidobridged and chelated with dithiophosphate or dithiocarbamate ligands.
Metal salts of fatty acids are well known materials. Fatty acids are generally hydrocarbon-based carboxylic acids, both synthetic and naturally occurring, preferably aliphatic acids, although acids containing aromatic functionality are also included. Occasional heteroatom substitution can be permitted in the hydrocarbyl portion of the fatty acid, consistent with the definition of xe2x80x9chydrocarbyl,xe2x80x9d below. Preferably the acid contains 14 to 30 carbon atoms, more preferably 16-24 carbon atoms, and preferably about 18 carbon atoms. The acid can be straight chain (e.g. stearic) or branched (e.g., isostearic). The acid can be saturated or it can contain olefinic unsaturation. A preferred acid is oleic acid, and the correspondingly preferred salt is zinc oleate, a commercially available material, the preparation of which is well known and is within the abilities of the person skilled in the art.
The zinc salt can be a neutral salt, that is, in which one equivalent of zinc is reacted with one equivalent of acid such as oleic acid. Alternatively, the zinc salt can be a slightly basic salt, in which one equivalent of a zinc base is reacted with somewhat less than one equivalent of acid. An example of such a material is Zn4Oleate6O1.
Alkyl-substituted imidazolines are also well known materials. They can generally be formed by the cyclic condensation of a carboxylic acid with a 1,2 diaminoethane compound. They generally have the structure
where R is an alkyl group and Rxe2x80x2 is a hydrocarbyl group or a substituted hydrocarbyl group, including xe2x80x94(CH2CH2NH)nxe2x80x94H groups.
Among the numerous suitable carboxylic acids useful in preparing the imidazoline are oleic acid, stearic acid, isostearic acid, tall oil acids, and other acids derived from natural and synthetic sources. Specially preferred carboxylic acids are those containing 12 to 24 carbon atoms including the 18 carbon acids such as oleic acid and stearic acid. Among suitable 1,2 diaminoethane compounds are compounds of the general structure Rxe2x80x94NHxe2x80x94C2H4xe2x80x94NH2, where R is a hydrocarbyl group or a substituted hydrocarbyl group (e.g., hydroxy hydrocarbyl, aminohydrocarbyl). A preferred diamine is N-hydroxyethyl-1,2-diaminoethane, HOC2H4NHC2H4NH2.
A preferred alkyl-substituted imidazoline is 1-hydroxyethyl-2-heptadecenyl imidazoline.
Another type of friction modifier includes borated epoxides, which are described in detail in U.S. Pat. No. 4,584,115, and are generally prepared by reacting an epoxide, preferably a hydrocarbyl epoxide, with boric acid or boron trioxide. The epoxide can be expressed by the general formula
wherein each R is independently hydrogen or a hydrocarbyl group containing 8 to 30 carbon atoms, at least one of which is hydrocarbyl. Also included are materials in which any two of the R groups together with the atoms to which they are attached, for a cyclic group, which can be alicyclic or heterocyclic. Preferably one R is a hydrocarbyl group of 10 to 18 carbon atoms and the remaining R groups are hydrogen. More preferably the hydrocarbyl group is an alkyl group. The epoxides can be commercial mixtures of C14-16 or C14-18 epoxides, which can be purchased from ELF-ATOCHEM or Union Carbide and which can be prepared from the corresponding olefins by known methods. Purified epoxy compounds such as 1,2-epoxyhexadecane can be purchased from Aldrich Chemicals. Alternatively this material can be a reactive equivalent of an epoxide. By the term xe2x80x9creactive equivalent of an epoxidexe2x80x9d is meant a material which can react with a boronating agent (described above) in the same or a similar manner as can an epoxide to give the same or similar products. An example of a reactive equivalent of an epoxide is a diol. Another example of a reactive equivalent to epoxides is the halohydrins. Other equivalents will be apparent to those skilled in the art. Other reactive equivalents include materials having vicinal dihydroxy groups which are reacted with certain blocking reagents. The borated compounds are prepared by blending the boron compound and the epoxide and heating them at a suitable temperature, typically 80xc2x0 to 250xc2x0 C., until the desired reaction has occurred. A preferred borated epoxide is the borated epoxide of a predominantly 16 carbon olefin.
The amount of the friction modifier component is preferably 0.1 to 0.45 percent by weight of the composition, preferably 0.15 to 0.3 percent, and more preferably 0.2 to 0.25 percent by weight. The total amount of the friction modifiers (of all types) is preferably that which provides a metal-to-metal coefficient of friction of at least 0.120 as measured at 110xc2x0 C. by ASTM-G-77, using the composition as a lubricant, since such minimum friction is desirable for the presently contemplated application. Preferably the amount of friction modifiers is sufficient to provide a coefficient of friction of 0.125 to 0.145, and more preferably about 0.135.
Other materials often used in ATFs and CVT fluids include antioxidants, including hindered phenolic antioxidants, secondary aromatic amine antioxidants, sulfurized phenolic antioxidants, oil-soluble copper compounds, phosphorus-containing antioxidants, organic sulfides, disulfides, and polysulfides. Other components include metal deactivators such as tolyltriazole, benzotriazole, and the methylene-coupled product of tolyltriazole and amines such as 2-ethylhexylamine. Such metal deactivators can also be useful in adjusting the metal-to-metal friction in push belt CVTs. Other components can include seal swell compositions, such as isodecyl sulfolane (that is, isodecyl-3-sulfolanyl ether), which are designed to keep seals pliable. Also permissible are pour point depressants, such as alkylnaphthalenes, polymethacrylates, vinyl acetate/fumarate or /maleate copolymers, and styrene/maleate copolymers. These optional materials are known to those skilled in the art, are generally commercially available, and are described in greater detail in published European Patent Application 761,805. Also included can be corrosion inhibitors, dyes, fluidizing agents, and antifoam agents. Each of these materials may be present in conventional and functional amounts.
The composition of the present invention can be supplied as a fully formulated lubricant or functional fluid, or it can be supplied as a concentrate. In a concentrate, the relative amounts of the various components will generally be about the same as in the fully formulated composition, except that the amount of oil of lubricating viscosity will be decreased by an appropriate amount. The absolute percentage amounts of the remaining components will be correspondingly increased. Thus, when the concentrate is added to an appropriate amount of oil, the final formulation of the present invention will be obtained. A typical concentrate of the present invention may contain at least 2500 parts per million of boron.
Thus, in a fully formulated composition, the amount of the oil of lubricating viscosity will typically be a major amount, or 50 to 95 parts by weight. In a concentrate, similarly, the amount of the oil of lubricating viscosity will typically be 10 to 50 parts by weight or other intermediate values that may be appropriate. Other amounts of the various components may be independently selected from a consideration of the broad, preferred, and most preferred percent ranges of such components set forth above. An exhaustive listing of such combinations on a parts-by-weight basis is not recited herein for the sake of brevity; however, such combinations can well be determined by the person skilled in the art seeking to prepare a concentrate.
As used herein, the term xe2x80x9chydrocarbyl substituentxe2x80x9d or xe2x80x9chydrocarbyl groupxe2x80x9d is used in its ordinary sense, which is well-known to those skilled in the art. Specifically, it refers to a group having a carbon atom directly attached to the remainder of the molecule and having predominantly hydrocarbon character. Examples of hydrocarbyl groups include:
(1) hydrocarbon substituents, that is, aliphatic (e.g., alkyl or alkenyl), alicyclic (e.g., cycloalkyl, cycloalkenyl) substituents, and aromatic-, aliphatic-, and alicyclic-substituted aromatic substituents, as well as cyclic substituents wherein the ring is completed through another portion of the molecule (e.g., two substituents together form a ring);
(2) substituted hydrocarbon substituents, that is, substituents containing non-hydrocarbon groups which, in the context of this invention, do not alter the predominantly hydrocarbon substituent (e.g., halo (especially chloro and fluoro), hydroxy, alkoxy, mercapto, alkylmercapto, nitro, nitroso, and sulfoxy);
(3) hetero substituents, that is, substituents which, while having a predominantly hydrocarbon character, in the context of this invention, contain other than carbon in a ring or chain otherwise composed of carbon atoms. Heteroatoms include sulfur, oxygen, nitrogen, and encompass substituents as pyridyl, furyl, thienyl and imidazolyl. In general, no more than two, preferably no more than one, non-hydrocarbon substituent will be present for every ten carbon atoms in the hydrocarbyl group; typically, there will be no non-hydrocarbon substituents in the hydrocarbyl group.
It is known that some of the materials described above may interact in the final formulation, so that the components of the final formulation may be different from those that are initially added. For instance, metal ions (of, e.g., a detergent) can migrate to other acidic or anionic sites of other molecules. The products formed thereby, including the products formed upon employing the composition of the present invention in its intended use, may not susceptible of easy description. Nevertheless, all such modifications and reaction products are included within the scope of the present invention; the present invention encompasses the composition prepared by admixing the components described above.

High boron formulations for fluids continuously variable transmissions


An automotive vehicle fluid jet pump 7 is provided including a first chamber 340 having a rear end 348 sealed from a front end 344 by a pressure communicative boundary 352. The first chamber front end 344 has an inlet 332 fluidly connected with a source of pressurized fluid. The first chamber front end 344 also has a nozzled outlet 372. A second chamber 376 is provided having a first inlet fluidly connected with the first chamber outlet 372. The second chamber 376 has a second inlet 380 fluidly connected with a sump. The second chamber has a delivery outlet 334. A valve member 400 is operatively associated with the first chamber boundary 352 for controlling a flow from the first chamber inlet 332 through said first chamber outlet 372. A position of the valve member 400 with respect to said first chamber outlet 372 is responsive to a pressure differential between the first chamber front end 344 and rear end 348.

The present invention relates to fuel tank jet pumps, which are used in an automotive vehicle, to transfer fuel from a fuel supply tank, to a fuel tank conditioning reservoir, prior to delivery to the vehicle fuel system. In particular, the variable orifice, pressure compensated jet pump of the present invention maintains close to peak operating efficiency in situations where the fluid viscosity range is broad, or where the driving flow rate varies significantly.
Conventional jet pumps used for automotive applications are usually of the fixed orifice type. When used with fluids having a narrow viscosity range, as well as a supply pressure with minimal variation, the jet pump will have a flow rate also with minimal variation. Minimal flow rate variation maintains an almost constant velocity in the driving fluid jet. The above-noted properties enable conventional jet pumps to be designed to operate in a narrow range, at reasonable efficiency.
Jet pumps are typically used to maintain fuel in a fuel tank conditioning reservoir (commonly referred to as a fuel delivery module) inside the fuel tank, just prior to fuel delivery to the vehicle fuel system. Jet pumps may also be used to transfer fuel from a secondary fuel tank to a main fuel tank or from a secondary fuel reservoir to a main reservoir, in multi sump or saddle-type fuel tanks.
Jet pumps are normally driven by a fuel bleed from a fuel feed pump system. This fuel feed pump system typically has minimal variation in pressure, as well as having more than adequate flow capacity for the main fuel system, such that excess flow can be taken to drive the jet pump(s). Where fuel feed pump capacity is marginal, the fuel returned from the fuel system may be used to drive the jet pump(s), but occasionally with some loss in peak efficiency, due to the possible fuel return line flow variation.
If the fixed orifice jet pump is used with fluids having a broad viscosity range (due to fluid composition variations or variations in fluid temperature), the efficiency variation of the jet pump will be much greater. Also, using a fixed orifice jet pump on a fuel return system, where the fluid flow rate can vary significantly, may cause excessive system back pressure, unless a pressure relief valve is added.
It is desirable to provide a variable orifice, pressure compensated jet pump which will not only prevent the excessive back pressure, but will adjust the orifice to handle the variation in flow and viscosity, maintaining a near constant driving fluid velocity, which will keep the fuel jet pump working close to its peak efficiency.
It is additionally desirable to provide a variable orifice, pressure compensated fuel jet pump which can be used with the fuel system return flow driving the jet pump, even if the flow varies significantly, while controlling (limiting) the back pressure in the fuel return line.
To make manifest the above delineated and other desires, the revelation of the present invention is brought forth. In a preferred environment, the present invention provides a diesel powered automotive vehicle fuel system which includes a fuel tank with multiple control volumes. The fuel tank has a first control volume or fuel module and a second control volume. A first source of pressurized diesel fuel typically provided by an injector servo return, high pressure pump coolant fuel return, or a branch line from the fuel feed pump is connected with a pressurized fuel supply line having an outlet. The outlet of the pressurized fuel supply line is fluidly connected with a first chamber. The first chamber has a rear end which is sealed from a front end by a spring-biased diaphragm. The front end of the first chamber has a nozzled outlet. A second chamber is provided opposite the first chamber having an inlet in fluid communication with the first chamber outlet. The second chamber has an outlet fluidly connected with the first control volume. The second chamber also has an inlet fluidly connected with the second control volume. The first and second chambers cooperate to provide a jet pump to deliver diesel fuel from the second control volume to the first control volume. A valve member operatively associated with the spring-biased diaphragm is fixably connected thereto. The valve member has a head which gives the nozzle of the first chamber a variable opening orificed area. The valve member by virtue of its connection with the diaphragm, is sensitive to pressure differentials between the first chamber front end and the first chamber rear end. The rear end of the first chamber is exposed by fluid connection with the second volume. Accordingly, the valve member functions to maintain an approximate constant fuel flow velocity through the nozzle of the first chamber. Accordingly, efficiency of the jet pump is maintained regardless of the fuel viscosity and flow rate that is delivered to the first chamber via the pressurized fuel source.
Not only is the efficiency of the jet pump maintained over various viscosity ranges of the diesel fuel, but the back pressure of the system can be held sufficiently that low back pressure tolerant injector fuel returns associated with high pressure common rail diesel injection systems can be utilized to provide the pressurized fuel source.
It is a feature of the present invention to provide an automotive vehicle fuel system having a jet pump to deliver fuel from a second control volume to a first control volume utilizing a jet pump which is pressure compensated.
It is also a feature of the present invention to provide an automotive vehicle fuel system having a saddle tank with a jet pump to deliver fuels with variable viscosity, such as diesel fuel, from a secondary control volume to a first control volume of the fuel tank. The system utilizes a pressure compensated jet pump which automatically adjusts to maintain the fuel velocity through the jet pump at a constant velocity to maintain the efficiency of the jet pump during various changes in the fuel viscosity.
The above-noted features and other advantages of the present invention will become more apparent to those skilled in the art as the invention is further explained in the accompanying drawings and detailed description.

Variable orifice, pressure compensated automated fuel jet pump


A collapsible tricycle for the use of young children has a front wheel, two rear wheels, a saddle, and a frame, to which the saddle is pivoted. The frame includes a front part, a stationary part secured to the front part, a rear part, and a connecting rod. The stationary part has two parallel walls at the rear portion; the front end of the saddle is pivotally connected to upper portions of the walls; the front portion of rear frame part is pivotally connected to the lower portions of the walls. The rear frame part has two parallel walls defining a space wider than the stationary part such that the stationary part can be partially received in the space when the tricycle is folded, allowing the folded tricycle to be relatively compact. The middle of the saddle is pivoted to the rear frame part. And, the connecting rod is pivoted to both the stationary part and the rear frame from two ends for preventing both from moving relative to each other when the tricycle is ridden. The bottom of the rear part of the saddle is stably supported on the rear frame when the tricycle is stretched. In addition, an engaging rod of the saddle is biased forwards to engage engaging gaps of the rear frame by a spring for preventing the tricycle from being accidentally folded; a pull handle is connected to the engaging rod for a user to pull to disengage the rod from the gaps.

The present invention relates to a collapsible tricycle for the use of young children, and more particularly, to one which will not be accidentally folded and so there will not be accidental folding that would cause the users to get hurt.
Tricycles are one of the most popular toys for young children. Conventional tricycles for the use of young children includes a rigid frame, a saddle, a front wheel, two rear wheels, a handle bar, and a pair of pedals connected to the front wheel. Riding on such a tricycle is very safe and fun. However, being not able to be collapsed, such a tricycle will take relatively much space when it is not used; when the parents wants to visit their relatives or friends or go out for vacation with their children, and want to carry the children""s tricycle in the trunk of the car, the unfoldability of the tricycle is found to be a big drawback, and would cause the tricycle to take too much space or even be not able to be put into the trunk.
And, people living in the cities have relatively limited storage space in their homes, and therefore like to buy objects that can be collapsed for easy storage. Therefore, several collapsible tricycles for the use of young children have been made, including the one which was disclosed in R.O.C. Patent No. 88205478. Although the collapsible tricycle according to this patent is more convenient than the unfoldable ones, it is found to have drawbacks as follows:
1. Referring to FIGS. 8, 9 and 10, which shows a part of the tricycle, when the tricycle is moved along on a ground full of bumps and holes or hits something, the U-shaped connecting rod 43 is likely to fall off the connect rod 41, which is pivoted to the U-shaped rod 43. And, the fall-off the U-shaped rod 43 would cause danger.
2. The spring 44 is the only device provided for keeping the pivoted components of the tricycle in the stretched in-use positions, in other words, there is no other locking device for fixing the pivoted components in position. Therefore, the tricycle is likely to make big noise or even accidentally fold up when it is moved on a ground fill of bumps and holes.
3. The tricycle is not ideally compact when it is in the collapsed position.
Therefore, it is a first object of the present invention to provide a collapsible tricycle for the use of young children, of which the saddle is held on the frame with ideal stability.
It is a second object of the present invention to provide a collapsible tricycle, of which a rear frame part has engaging gaps for an engaging rod movably connected to the saddle to disengagably engage such that the same can t be accidentally folded.
It is a third object of the present invention to provide a collapsible tricycle, of which a stationary part of the frame can be partially received in the rear frame part when the tricycle is folded such that the folded tricycle has relatively compact size.
The collapsible tricycle includes a front frame part, a stationary frame part secured to the front frame part, a saddle and a rear frame part. A front wheel and handlebars are connected to the front frame part. A pair of rear wheels are connected to the rear frame part.
The rear portion of the stationary frame part has two parallel walls, which have upper, and lower pivotal holes for a front portion of the saddle, and a front end of a connecting rod to be pivoted to respectively.
The rear frame part has two parallel walls, and an interposed board part connected to upper edges of the walls thereof. The walls of the rear frame part defines a front space, and a receiving space behind the front space; the front of the board part is a distance behind the front end of the walls. The connecting rod is pivoted to second pivotal holes of front parts of the walls of the rear frame from a rear end. And, the rear frame part is pivoted to the saddle from first pivotal holes of the front parts of the walls thereof; when the tricycle is in a stretched position, a bottom of the rear part of the saddle is supported on the front edge of the interposed board part. The front edges of the walls of the rear frame part further have engaging gaps for an engaging rod movably connected to the saddle to disengagably engage to secure the saddle in the stretched position.

Collapsible tricycle for the use of young children


The present invention relates to a composite flexible hose, preferably for use in automotive air conditioning systems, with improved thermal resistance. The hose consists of an innermost core layer, a friction rubber layer, an intermediate reinforcement layer, and an external cover layer. The innermost layer is a non-plasticized polyamide mixed with a minor portion of polyolefin corresponding to the main rubber constituent of the friction coat layer. The friction coating is formed of a rubber composite of two EPDM rubbers at a weight ratio of 50/50 and 75 parts by weight of carbon black. The intermediate fibrous reinforcement layer is formed of aramid. The external layer is an acrylate rubber comprising a blend of two ethylene acrylates at a weight ratio of 50/50 and 80 parts by weight of carbon black.

The disclosed invention is directed toward an air conditioning hose. Specifically, the disclosed invention is an automotive air conditioning hose capable of withstanding high temperature fluid flow of up to at least 150xc2x0 C. therein.
Hoses have been developed which are useful for automobile air conditioners, wherein hoses or other suitable flexible conduit members are employed for the purpose of joining the principal operating components of the refrigerating device. These hoses should have good flexibility, high strength, the ability to bend to small radii without kinking, small outside diameter in relation to inside diameter and impermeability to the fluids involved. In addition, these refrigeration hoses are subjected to temperature extremes in under-the-hood applications, and further, must meet requirements for proper coupling attachment.
Prior art automotive air conditioner hoses employ a three-layer structure. The innermost tubular layer of the hose is typically formed of an elastomeric material intended to keep the refrigerant fluid and compressor lubricant in the hose and moisture and air out. A layer of reinforcing braiding is wound upon the outside surface of the inner tube. An outer layer of elastomer resistant to ozone, engine oil and other contaminating materials likely to be present in the engine compartment is typically extruded over the braided reinforcement. In hoses of this type, the inner layer is acrylonitrile-butadiene rubber or chlorosulfonated polyethylene, the braiding fibers may be rayon and other conventional fibers, and the outer layer is neoprene or EPDM.
Even though numerous refrigerant hose designs have been developed, they fail to combine low Freon permeability, low water permeability, high flexibility, vibration resistance and good coupling properties to the hose over temperature extremes.
Conventional hoses, due to the thickness and a corresponding lack of flexibility, provide little noise damping. The noise generated can be detected within the passenger cabin of the automobile. It is desired by the automotive industry to reduce cabin noise as much as possible to provide a quiet ride. The more flexible the hose is, the greater is the noise damping effect of the hose. The present invention is directed toward a hose with greater flexibility and thus greater noise dampening.
The normal operating temperatures encountered by air conditioning hose assemblies employed in automotive air conditioning generally ranges from about xe2x88x9230xc2x0 to about 120xc2x0 C. Design specifications require that such hose assemblies operate equally well at temperature ranges of about xe2x88x9240xc2x0 to 150xc2x0 C. The higher temperatures are due mainly to the location of the system proximate the engine as well as from the heat generated in compressing the refrigerant as a gas.
U.S. Pat. No. 4,633,912 discloses a composite hose for Freon gas, comprising a polyamide core tube, an elastic friction layer having the specific composition and being directly provided on a core tube, a first reinforcement strand layer, an adhesive barrier friction layer, a second reinforcement strand layer, and then a cover layer. The elastic friction layer provided directly on the core tube comprises (a) a base rubber selected from EPDM, a copolymer of butadiene, polychloroprene, polybutadiene, polyisoprene or a mixture thereof, (b) a calcium ion source, (c) resorcinol or a phenol-based adhesive system, and (d) a peroxide or a sulfuric vulcanizing agent. The calcium source (b) is said to make better adhesion to a polyamide of the core tube. The adhesive barrier friction layer being present between the first and second reinforcement strand layers is provided to minimize a friction of the strands, and is made of a copolymer of ethylene and acrylic acid. For the cover layer, a halogenated butyl rubber containing bis-dienophile as a crosslinking agent is used.
U.S. Pat. No. 5,488,974 discloses a composite hose for automotive air conditioning systems. The hose consists of the innermost layer, the intermediate rubber layer, a fibrous reinforcement layer and an external rubber layer, each of which is formed in this order from the inside. The innermost layer is formed of a modified polyamide obtainable by blending of a polyamide and a carboxyl-containing modified polyolefin, and the intermediate rubber layer is formed of a rubber composition obtainable by a blend of 10 to 50 parts by weight of silicic acid or a salt thereof and 5 to 15 parts by weight of a brominated alkylphenol formaldehyde resin per 100 parts of the rubber material obtainable by blending butyl rubber and a halogenated butyl rubber at a weight ratio of 50/50 to 0/100.
The disclosed invention is a hose, preferably for use in automotive air conditioning units. The four layer hose exhibits high flexibility, high gas impermeability, and a resistance to high temperatures within the range of 150xc2x0 C.
The present invention discloses a hose comprising an innermost core layer comprised of non-plasticized polyamide; an intermediate reinforcing layer comprised of aramid fibers, and an outermost layer of acrylic rubber compound.
A further aspect of the disclosed invention includes a friction coat rubber layer disposed between the innermost core layer and the intermediate reinforcing layer, the friction coat layer comprised of ethylene propylene diene rubber and 75 parts by weight of carbon black.
A further aspect of the disclosed hose is the friction coat rubber is a 50/50 weight percent blend of two ethylene propylene diene rubbers, the two rubbers having differing Mooney viscosities.
The disclosed invention further discloses an automotive air conditioning hose with an innermost layer, a friction coating layer, an intermediate reinforcing layer, and an outermost layer, wherein 1) the innermost layer is comprised of non-plasticized nylon-6 blended with an EPDM rubber at a weight ratio of 95/5 to 85/15; 2)the friction coat layer is comprised of a 50/50 weight percent blend of two EPDM rubber with differing Mooney viscosities, and 75 parts by weight of carbon black; 3) the intermediate reinforcing layer is comprised of adhesively treated aramid fibers; and 4)the outermost layer is comprised of a 50/50 weight percent blend of two ethylene acrylates with differing Mooney viscosities, and 80 parts by weight of carbon black.
The hose of the present invention is comprised of a core tube. The core tube is formed from a selected resin, with high impermeability against the fluid which flows therein. The core tube is provided with an outer friction layer, selected for its adhesion ability to the core tube and the adjacent reinforcement layer. The reinforcement layer is comprised of a strand which provides a high flex dynamic performance. The outermost layer of the tube is a thermoplastic rubber layer.
The core layer of the hose is a resin polyamide. Polyamide resin is preferred as providing a good balance between impermeability and flexibility. To provide adhesion to the friction coat layer, the polyamide resin may be formed of a blend material consisting of polyamide resin and a polyolefin rubber material. For the improved adhesion to the friction coat layer, the polyolefin selected should be selected from among the main rubber constituents of the friction coat layer. The weight ratio of polyamide to polyolefin ranges from 95/05 to 85/15. Nylon-6 is preferable as the selected polyamide resin, with a 6% blend of ethylene propylene diene rubber, corresponding to the preferred composition of the friction coat layer. Other conventional nylons, such as nylon 66, nylon 11, were determined to not be able to provide the required adhesion in combination with the needed flexibility and impermeability as the nylon 6.
Additionally, the polyamide resin is non-plasticized. The core may be formed by conventional methods, such as extrusion. While conventionally, a non-plasticization of the resin would result in a tube of higher bending strength and lower flexibility, the effects are mitigated by optimizing the thickness of the inner tube.
The thickness of the differing layers of the hose is linked to the desired characteristics, as excessively thin wall thicknesses or excessively thick wall thicknesses present flexibility or kinking problems or coupling compatibility problems of the final hose composite. For every thousandths of a centimeter increase in the thickness of the hose, the flexibility of the hose decreases. For hoses with an inside diameters (ID) of 13 mm and an outside diameter (OD) of about 19.5 mm, the ID of the hose has a maximum value of 13.46 mm and a minimum value of 12.44 mm, while the OD has a maximum value of 19.9 mm and a minimum value of 18.9 mm. The wall thickness of the hose is within the range of 2.72 mm and 3.73 mm. But, as every incremental thickness of the hose decreases the desired properties of the hose, the smallest wall thickness, without a loss of impermeability and creation of kinking problems, is preferred. The preferred wall thickness for a 13 mm ID hose, in accordance with the disclosed invention, is about 3.17 mm.
The wall thicknesses of the polyamide core is within the range of 0.14 to 0.16, with a preferred thickness of 0.15 mm, for a 13 mm ID hose. This thickness provides the required flexibility without kinking. One skilled in this art will appreciate that for other size hoses, the wall thickness for the polyamide core may differ, yet still provide the necessary flex, impermeability and freedom from kinking.
Radially outward of the nylon innertube is an elastomeric friction layer. One skilled in this art will appreciate that the elastomeric friction layer may be applied in the form of a sheet either spirally wrapped or butt seamed. These methods of applying such layers are known in the art, and variations thereof are contemplated herein.
The elastomeric friction layer is comprised of a base polymer of ethylene propylene diene rubbers (EPDM). Suitable EPDM""s are ethylene propylene norbornene terpolymers, ethylene propylene-1,4-hexadiene terpolymers, ethylene propylene dicyclopentadiene terpolymers and the like. The friction layer also contains an adhesive system and a curative.
The peroxide curative useful in the elastomeric friction layer are those that are normally used in such base stocks. For example peroxides such as dicumyl peroxide, xcex1-xcex1-bis(t-butylperoxide)diisopropylbenzene, benzoyl peroxide, 2,4-dichlorobenzoyl peroxide, 1,1-bis(t-butylperoxy)3,3,5-trimethylcyclohexane, 2,5-dimethyl-2,5-bis(t-butylperoxy)hexane, 2,5-dimethyl-2,5-bis(t-butylperoxy)hexyne-3, and n-butyl 4,4-bis(t-butylperoxy)valerate. The most preferred and commercially available peroxide curatives are Percadox TM 14/40 from Noury Chemical Corporation and Vul-Cup TM from Penwalt Corporation. From 1 to about 10 parts of peroxide are utilized based on 100 parts of base polymer. Peroxides are preferred as the curative since they are less sensitive to premature resin formation.
The adhesive systems useful in this invention are the conventionally known adhesive systems for use with peroxide cured elastomers. For example, maleinized 1,2-polybutadiene resin.
The friction layer composition may also contain various additives in conventional or suitable amounts. Such additives may include, and are not limited to, retardants to prevent an unduly quick cure, antioxidants, processing aids, reinforcing agents such as carbon black, silica, and the like, and various plasticizers.
The thickness of the friction layer, for 13 mm ID hoses, is optimized at a thickness ranging from about 1.000 to 1.020 mm, with a preferred thickness of 1.016 mm. One skilled in this art will appreciate that for other size inside diameter hoses, the wall thickness for the friction layer may vary, yet still provide the necessary adhesion characteristics.
Outward of the friction barrier layer is a reinforcement layer. The reinforcement layer may be comprised of spirally wound reinforcement strands, laid under sufficient tension to improve the strength of the hose structure. Alternatively, the reinforcement layer may be a braided layer. The reinforcement strands are laid at angles such that flexing of the hose will not result in collapse or kinking. An angle such as 52xc2x0 to 56xc2x0 with respect to the centerline of the hose has been found acceptable. Most preferably, a neutral angle of 54xc2x0 44xe2x80x2 or below has been found advantageous for the spiral wraps.
To provide the inventive hose with excellent strength and flexibility, a reinforcement strand with high flex dynamic performance is desired. Herein the reinforcement strands are adhesively treated aramid fibers.
The thickness of the reinforcement layer is dependent upon the strand thickness. To achieve the desired overall thickness of the hose, the reinforcement layer has a thickness of about 0.625 to about 0.645 mm, with a preferred width of 0.635 mm for the 13 mm ID hose.
The outermost cover layer is placed on the outside of the hose construction. The cover layer is an acrylic rubber compound. Desired for the present invention are various terpolymers of ethylene, acrylate, and unsaturated carboxy acids having from 3 to 10 carbon atoms or combinations thereof. The acid, preferably, is acrylic acid or methacrylic acid. The terpolymers contain at least 50 mole percent of ethylene, generally from about 0.5to about 10 mole percent of the acid, and about 10 to about 49.5 mole percent of the alkyl acrylate.
The selected terpolymer or combination of terpolymer is combined with a curative. Suitable curatives or accelerators include salts of fatty acids. Additional curatives may be added.
The cover layer composition of the present invention may also contain various additives in conventional or suitable amounts. Such additives may include, and are not limited to, retardant to prevent an unduly quick cure, antioxidants, processing aids, colorants or pigments, reinforcing agents such as carbon black, silica, and the like, various flame retardants, and various plasticizers.
The preferred cover thickness for the 13 mm ID tube ranges from 1.35 to 1.45 mm, with an preferred thickness of about 1.37 mm. One skilled in this art will appreciate that for other size hoses, the wall thickness of the various layers of the disclosed hose may vary, while maintaining the desired characteristics in order to provide a highly flexible tube.
The invention will be better understood by reference to the following example which serves to illustrate but not to limit the scope of the present invention.