TORSIONAL DAMPER FOR A VEHICLE TRANSMISSION SYSTEM

Abstract

A torsional damper for vehicle transmission systems comprises an input element rotationally movable around an axis and exhibiting at least one window comprising two angularly spaced lateral edges and a radially external edge. An output element is rotationally movable around the axis and exhibits at least one window comprising two angularly spaced lateral edges and a radially external edge. An elastic return member capable of being received simultaneously in the window of the input element and the window of the output element generates a force acting against rotation of the output element with respect to the input element. An additional element is rotationally movable around the axis and integral with one of the input element and output element. The additional element exhibits an edge comprising at least one region projecting radially into the window of the input element and output element with which the additional element is integral.

Claims

1. A torsional damper (2) for a vehicle transmission system, comprising: an input element (6) rotationally movable around an axis (X) and exhibiting at least one window (15) comprising two angularly spaced lateral edges (20) and a radially external edge (21); an output element (8) rotationally movable around the axis (X) and exhibiting at least one window comprising two angularly spaced lateral edges and a radially external edge, an elastic return member (9) being capable of being received simultaneously in the window (15) of the input element (6) and in the window of the output element (8) so as to generate a force acting against rotation of the output element (8) with respect to the input element (6); and an additional element (10) rotationally movable around the axis (X) and integral with one of the input element (6) and output element (10), the additional element (10) exhibiting at least one edge (25), said edge (25) comprising at least one region (30) projecting radially into the window (15) of that one of the input element (6) and output element (8) with which the additional element (10) is integral, the damper (2) being capable of being integrated into a friction disk (1) for a clutch, the input element (6) being constituted by a web, the output element (8) being constituted by two guide washers axially surrounding the web, and the additional element (10) being constituted by a support disk capable of supporting at least one friction lining.

2. The torsional damper (2) according to claim 1, the additional element (10) being integral with the input element (6).

3. The damper (2) according to claim 1, comprising an elastic return member (9) received simultaneously in the window (15) of the input element (6) and in the window of the output element so as to generate a force acting against rotation of the output element with respect to the input element (6), the elastic return member (9) also being received radially internally with respect to the edge (25) of the additional element (10).

4. The damper (2) according to claim 2, wherein each angular end of the elastic return member (9) being in contact with a seat (27).

5. The damper (2) according to claim 1, wherein said region (30) of the edge (25) of the additional element (10) being a central region of said edge (25).

6. The damper (2) according to claim 1, wherein said region (30) of the edge (25) of the additional element (10) being rectilinear.

7. The damper (2) according to claim 1, wherein the ratio between the angle (.sub.1) measured from the rotation axis (X) between the angular ends of said region (30), and the angle (.sub.2) measured from the rotation axis between the angular ends of the edge (25) of the additional element (10) in which that region (30) is configured, being between 0.15 and 0.5, in particular between 0.15 and 0.30.

8. The damper (2) according to claim 1, wherein the maximum distance (D) that said region (30) projects into the window of that one of the input element (6) and output element (8) with which the additional element (10) is integral being at least 0.2 mm.

9. The damper (2) according to claim 1, wherein the rigid connection between the additional element (10) and that one of the input element (6) and output element (8) with which the additional element (10) is integral comprising rivets (14).

10. The damper (2) according to claim 9, wherein the rigid connection between the additional element (10) and that one of the input element (6) and output element (8) with which the additional element is integral comprising a local weld of that portion of the additional element (10) defined radially internally by the edge (25) of the additional element, and that portion of the input element (6) or output element (8) defined radially externally by the radially external edge of its window.

11. The damper (2) according to claim 1, wherein: the input element (6) exhibiting a plurality of windows (15) succeeding one another angularly, each window (15) comprising two angularly spaced lateral edges (20) and a radially external edge (21); the output element (8) exhibiting a plurality of windows succeeding one another angularly, each window comprising two angularly spaced lateral edges and a radially external edge; and the additional element (10) exhibiting a plurality of windows (17), each window (17) comprising two angularly spaced lateral edges (23) and a radially external edge (25) in which said projecting region (30) is configured, each window (17) of the additional element (10) being axially opposite at least a portion of a window of the output element (8) and at least a portion of a window of the input element (6).

12. A friction disk (1) for a clutch, comprising: a hub (3) extending along an axis; a torsional damper (2) according to claims 1; and at least one friction lining (12) carried by the support disk (10) of the damper.

13. The damper (2) according to claim 2, comprising an elastic return member (9) received simultaneously in the window (15) of the input element (6) and in the window of the output element so as to generate a force acting against rotation of the output element with respect to the input element (6), the elastic return member (9) also being received radially internally with respect to the edge (25) of the additional element (10).

14. The damper (2) according to claim 3, wherein each angular end of the elastic return member (9) being in contact with a seat (27).

15. The damper (2) according to claim 2, wherein said region (30) of the edge (25) of the additional element (10) being a central region of said edge (25).

16. The damper (2) according to claim 3, wherein said region (30) of the edge (25) of the additional element (10) being a central region of said edge (25).

17. The damper (2) according to claim 4, wherein said region (30) of the edge (25) of the additional element (10) being a central region of said edge (25).

Description

[0050] A better understanding of the invention will be gained from reading the description below of a non-limiting exemplifying embodiment thereof and from an examination of the attached drawings, in which:

[0051] FIG. 1 schematically depicts a friction disk comprising a damper according to an exemplifying embodiment of the invention;

[0052] FIG. 2 is a view, along the axis of the disk, of a region thereof; and

[0053] FIG. 3 depicts detail III of FIG. 2.

[0054] FIG. 1 depicts a friction disk 1 equipped with a torsional damper 2 according to an exemplifying embodiment of the invention. This friction disk 1 comprises a hub 3 extending along an axis X. Hub 3 is installed, for example, on a region of an input shaft (not depicted) of a gearbox and is rotationally integral with that shaft.

[0055] In known fashion, damper 2 comprises an input element 6 and an output element 8 between which is interposed an elastic return member 9, the latter allowing a limited rotational displacement between input element 6 and output element 8. In the example described, input element 6 is constituted by a web rigidly coupled to a support disk 10 for friction linings 12. Support disk 10 constitutes an additional element for damper 2. The rigid coupling between web 6 and support disk 10 is effected, for example, with the aid of rivets 14.

[0056] As is evident from FIG. 1, output element 8 is constituted here by two axially offset guide washers arranged axially around web 6. Guide washers 8 are integral and are rotationally fastened on hub 3, for example by means of splines.

[0057] In the example considered, damper 2 comprises a plurality of elastic return members 9 succeeding one another angularly, each elastic return element 9 being, in this example, received concurrently [0058] in a window 15 configured in web 6, [0059] in a window 17 configured in support disk 10, and [0060] in a window configured in guide washers 8.

[0061] Windows 15 and 17 will now be described in further detail with reference to FIG. 2, in which guide washers 8 are not depicted for reasons of clarity.

[0062] Once web 6 and support disk 10 have been integrated with the aid of rivets 14, each window 15 of web 6 is axially and radially opposite a window 17 of support disk 10.

[0063] Each window 15 configured in web 6 is delimited on the one hand by: [0064] two angularly spaced lateral edges 20, and [0065] a radially external edge 21 and a radially internal edge 22.

[0066] Radially external edge 21 of a window 15 delimits a strip 16 of the web extending to radially external edge 18 of said web 6. In addition to the use of rivets 14 for rigidly coupling web 6 and support disk 10, each strip 16 of the web can be fastened by local welding to that portion of support disk 10 which is axially and radially opposite the latter.

[0067] Each window 17 is delimited on the one hand by: [0068] two angularly spaced lateral edges 23, and [0069] a radially external edge 25 and a radially internal edge 26.

[0070] As is evident from FIG. 2, here the edges of windows 15 and 17 are not rectilinear. In FIG. 1, the edges of window 17 configured in support disk 10 exhibit curved regions. In FIG. 1, radially internal edge 22 of window 15 configured in support disk 10 exhibits a succession of slots.

[0071] In the example depicted, radially internal edge 26 of window 17 configured in support disk 10 is, over its entire length, radially behind radially internal edge 22 of window 15 configured in web 6. In other words, edge 22 here projects over its entire length into window 17 configured in support disk 10.

[0072] As depicted in FIG. 2, each window 15 configured in web 6 extends over an angular sector, measured from axis X of the hub between two angular ends of radially external edge 21, that is less than the value of the angular sector measured from that same axis X between two angular ends of radially external edge 25 of the opposite window which is configured in support disk 10.

[0073] In the example considered, each elastic return member 9 is a spring extending between two angular ends, each angular end coming into abutment against: [0074] web 6, [0075] support disk 10, and [0076] guide washers 8.

[0077] In the example of FIG. 2, each angular end of spring 9 comes into contact with a seat 27. When damper 2 is in active, each seat 27 comes into abutment simultaneously against web 6 at a lateral edge 20 of window 15 configured in that web 6, and against guide washers 18 at a lateral edge of the windows configured in those guide washers 18.

[0078] As is evident from FIG. 3, radially external edge 25 of window 17 configured in support disk 10 comprises a region 30 projecting radially into window 15 configured in web 6. In the example depicted, region 30 is a central region of radially external edge 25 of window 17 configured in support disk 10. Region 30 here is unique, i.e. outside that region 30, radially external edge 25 of window 17 does not project into window 15 configured in web 6. Region 30 of the example considered is moreover rectilinear. In the example of FIG. 2, the remainder of radially external edge 25 of window 17 is constituted by concave regions 33.

[0079] Region 30 has a short length with respect to the total length of radially external edge 25; the ratio here between the angle .sub.1 measured from axis X between the angular ends of said region 30, and the angle .sub.2 measured from that same axis X between the angular ends of radially external edge 25 of window 17 configured in support disk 10, is between 0.15 and 0.5, being in particular between 0.15 and 0.30.

[0080] Furthermore, the maximum distance D by which region 30 projects into window 15 configured in web 6 is equal here to at least 0.2 mm. As is evident from FIG. 3, this maximum distance D is measured, between radially external edges 21 and 25 at the center of region 30, orthogonally to said region 30.

[0081] When web 6 is rotationally displaced in response to a torque exerted by the combustion engine associated with the transmission system into which friction disk 1 is integrated, that web 6 displaces each elastic return member 9 on which centrifugal forces are exerted. As long as the centrifugal forces remain below a given value, elastic return member 9 does not come into contact with region 30 of radially external edge 25 of the window configured in support 10, which projects into window 15 configured in the web. The presence of regions 30 does not change the functioning of friction disk 1.

[0082] When the centrifugal forces exerted on each elastic return member become too large, the elastic return member becomes displaced radially in window 15 until it comes into contact with region 30 of radially external edge 25 of window 17 configured in support disk 10. Thanks to that contact, support disk 10, which is more solid than web 6, absorbs a portion of the centrifugal forces that according to the existing art are applied only onto web 6. Support disk 10 thus plays the part of an additional element of damper 2, reducing the risk of wear on web 6.

[0083] The invention is not limited to what has just been described. In other examples that are not depicted, the input element of damper 2 is constituted by guide washers with which support disk 10 is integrated, the output element of damper 2 being constituted by web 6. In this case, region 30 of radially external edge 25 of window 17 configured in support disk 10 projects into the window configured in the guide washer.

[0084] In other examples, support disk 10 has no windows, edge 25 then being an edge of that disk 10.

[0085] The expression comprising a/an/one must be understood as a synonym of the expression comprising at least a/an/one, unless specified to the contrary.