Title of Invention: Torsional vibration damper
Abstract: A torsional vibration damper, in particular for clutches, includes a primary structural unit and a secondary structural unit which are rotatable relative to one another and connected to each other by a spring arrangement (7) including at least one thrust piston (71). At least the secondary structural unit (2) interacts with the thrust piston (71) of the spring arrangement via a contact surface with a radially directed surface component, wherein the contact surface (4) is formed on a separate third structural unit (3) situated between the secondary structural unit (2) and the spring arrangement (7), thereby ensuring a structurally simple heat insulation for a torsional vibration damper.
Detailed Description: Part PAC: DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS
Part PAR: Throughout all the Figures, same or corresponding elements are generally indicated by same reference numerals.
Part PAR_2: Turning now to the drawing, and in particular to FIGS. 1 and 2, there are shown sectional views of a first embodiment of a torsional vibration damper according to the present invention, for use in a motor vehicle and situated e.g. between the internal combustion engine and an output unit, e.g. a clutch or transmission, for attenuating vibrations caused by the internal combustion engine. The torsional vibration damper includes a primary structural unit 1, for example in the form of a hollow disk, and a secondary structural unit 2, for example also a disk-shaped element, whereby the primary and secondary structural units 1, 2 are supported by a bearing 10 for rotation relative to one another. On its side facing away from the primary structural unit 1, the secondary structural unit 2 has a friction surface 21 which forms part of a clutch. A spring arrangement, generally designated by reference numeral 7 includes a plurality of tangentially arranged compression springs 70 which separate two thrust pistons or wedges 71, respectively, and are received together with the wedges 71 in circumferentially spaced pockets 11 of the primary structural unit 1 so as to resiliently couple the primary structural unit 1 with the secondary structural unit 2.
Part PAR_3: A contact ring 3 with a polygonal shape is provided as a separate third structural unit between the primary structural unit 1 and secondary structural unit 2. The outside peripheral surface of the contact ring 3 serves as a contact surface 4 via which the separate third structural unit or contact ring 3 as well as the secondary structural unit 2 interact with the spring arrangement 7. Through compression of the springs 70 and friction of the wedges 71 as a result of i.a. a rotation of the secondary structural unit 2 and thus of the contact surface 4, relative to the primary structural unit 1, vibrations are attenuated.
Part PAR_4: As shown in FIGS. 1 and 2, the separate structural unit in the form of the contact ring 3 is supported by a support surface 20 of a projection 22 which extends out of the secondary structural unit 2. This projection 22 is smaller in an axial direction than the contact ring 3, so that the contact ring 3 is only in partial contact with the secondary structural unit 2 in an axial direction. The radial thickness of the projection 22 varies over the periphery such that the radial thickness of the projection 22 is greatest in the area of the wedges 71, and smallest in the middle of the springs 70 (cf. FIG. 2). This type of configuration is possible without any appreciable reduction in thermal resistance, since the contact ring 3 does not contact the wedges 71 in the area of the springs 70, so that no appreciable heat transport takes place in these regions. The support surface 20 supports the contact ring 3 in a radial direction, and complements the polygonal shape of the contact ring 3. This ensures a positive fit effective in the circumferential direction between the contact ring 3 and the secondary structural unit 2, so that the contact ring 3 may only rest against the support surface 20.
Part PAR_5: FIGS. 3 and 4 show a second embodiment of a torsional vibration damper according to the present invention, which differs from the embodiment of FIGS. 1 and 2 by the provision of a plurality of circumferentially spaced projections 22 to support the contact ring 3. This ensures a partial contact in circumferential direction between the contact ring 3 and the secondary structural unit 2. The support surface 20 formed commonly by the projections 22 for radially supporting the contact ring 3 is also suited to the polygonal shape of the contact ring 3, so that the secondary structural unit 2 and the contact ring 3 are connected together with a positive fit effective in the circumferential direction.
Part PAR_6: In the embodiment shown in FIGS. 5 to 8, the contact ring 3 has an essentially L-shaped cross section in the axial direction. On its side facing the secondary structural unit 2, the contact ring 3 rests on projections 22, which vary in their axial thickness and, similar to the projection 22 of the structural unit 2 according to the first embodiment, have a shape complementing the polygonal shape of the contact ring 3. On its side facing away from the secondary structural unit 2, the contact ring 3 has a radial member which engages in spaced-apart projections 22' of the secondary structural unit 2, thereby forming meshing gear teeth to realize in conjunction with the positive fit between the projection 22 and contact ring 3 a positive fit effective in circumferential direction between the contact ring 3 and the secondary structural unit 2. The secondary structural unit 2 is provided in the area between the projections 22 and 22' with a cylindrical outer surface having a radius which corresponds to the smallest inside radius of the contact ring 3. In this way, the contact ring 3 rests between the projections 22 and 22' only in the area of the springs 70 on the secondary structural unit 2.
Part PAR_7: While the invention has been illustrated and described as embodied in a torsional vibration damper, it is not intended to be limited to the details shown since various modifications and structural changes may be made without departing in any way from the spirit of the present invention.


{'bibliographic_information': "{'Patent Number': '062863908', 'Series Code': '9', 'Application Number': '218477&', 'Application Type': '1', 'Art unit': '362', 'Application Filing Date': '19981222', 'Title of Invention': 'Torsional vibration damper', 'Issue Date': '20010911', 'Number of Claims': '13', 'Exemplary Claim Number(s)': '1', 'Assistant Examiner': 'Kim; Chong H.', 'Primary Examiner': 'Bucci; David A.', 'Number of Drawing Sheets': '6', 'Number of figures': '8'}", 'source_file': './grant/2001/pftaps20010911_wk37.txt', 'source_data': 'USPTO-Grant'}