Torsional damping device and vehicle drive train

Abstract

The utility model relates to a torsion damping device, which comprises an input element (6), an output element (7) and a damping element (8). The input element (6) is configured to be restrained to rotate around a rotation axis (X) together with a driving shaft. An output element (8) configured to be constrained for rotation with the driven shaft; and at least one mechanical energy storage member (9) arranged between the input element (6) and the output element (8), the torsional damping device further comprising a torque limiter (4) comprising a cover (14), a pressure plate (16) and a disc (10) positioned axially between the cover (14) and the pressure plate (16), the torque limiter (4) further comprises an elastic element (20) configured to press the pressure plate (16) against the disc (10) and at least one liner (18, 19) arranged between the disc (10) and one of the solid components between the pressure plate (16) and the cover (14), the at least one liner (18, 19) being attached to the disc (10) or fixed to the one of the solid components and defining an annular contact area (50), characterized in that the elastic element (20) is configured to press the pressure plate (16) against the disc (10). The annular contact region (50) is radially delimited by at least one axial clearance region (51). The utility model further relates to a vehicle transmission system comprising the torsion damping device.

Description

Technical Field

[0001] The utility model relates to a torsion damping device, which is particularly suitable for being integrated into a transmission system of a vehicle. Background Art

[0002] Motor vehicles often include such torsional damping devices to filter out the non-cyclic behavior of the engine and allow smooth transmission. The filtering is usually performed by one or more spring-damper assemblies working in torsion and, when torque is transmitted, allows a relative rotational movement of a first rotating element of a drive element of the transmission coupled to the upstream of the damping device relative to a second rotating element of a driven element of the transmission coupled to the downstream of the damping device.

[0003] It is known practice to equip such a torsional damping device with a torque limiter configured to allow torque to be transmitted from a first rotating element to a second rotating element in normal operation and to limit the transmission when excessive torque is applied to the drive train, that is, when the torque exceeds a certain value. Friction elements or linings are located between the solid parts of the torque limiter, the purpose of these linings being to prevent the solid parts from rubbing against each other when excessive torque is applied, while allowing the two solid parts sandwiching the linings to rotate relative to each other to limit the transmission of torque.

[0004] Motor vehicle manufacturers and equipment suppliers seek to make torsional damping devices as compact as possible in order to significantly limit the axial space occupied and the impact on the amount of space required for the drive train. In this case, particular efforts are made to limit the thickness of the lining, which can lead to two solid parts rubbing together undesirably on each side of the lining, especially when one of the parts exhibits flatness defects and / or local wear of the lining. Utility Model Content

[0005] The utility model belongs to this situation, and particularly relates to a torsional damping device, which comprises: an input element, which is configured to be constrained to rotate with a drive shaft around a rotation axis; an output element, which is configured to be constrained to rotate with a driven shaft; and at least one mechanical energy accumulator component, which is arranged between the input element and the output element. The torsional damping device also includes a torque limiter, which includes a cover, a pressure plate and a disk axially inserted between the cover and the pressure plate. The torque limiter also includes an elastic element configured to press the pressure plate against the disk and at least one liner arranged between the disk and one of the solid parts serving as the pressure plate and the cover, at least one liner is fixed to the disk or to one of the solid parts, and simultaneously defines an annular contact area, characterized in that the annular contact area is radially bounded by at least one axial gap area.

[0006] It is to be understood here that the term "radial" is intended to encompass directions perpendicular to the axis of rotation of the input element, which is most typically the axis of rotation about which the torsional damping device is arranged.

[0007] The annular contact zone defined by the contact between the liner and the rigid component of the torque limiter may be considered to be continuous around the entire circumference of the torque limiter, whether the liner is continuous or segmented.

[0008] The lining is configured to restrict the solid parts of the torque limiter positioned relative to each other from rubbing together when the torsional damping device is subjected to excessive torque, while the torque limiter allows the solid parts to rotate relative to each other.

[0009] The lining is made of organic material. Alternatively, the lining is based on metal fibers or powders. Alternatively, the lining is a coating.

[0010] The axial clearance zone according to the invention delimits the annular contact zone in such a way that the axial distance measured along the rotation axis between two solid parts of the torque limiter sandwiching the liner is greater there than at the annular contact zone defined by the presence of the liner.

[0011] This local increase in the distance between the solid parts of the torque limiter makes it possible to avoid contact between these parts without the presence of a lining between them, in particular in the case of flatness defects in one or the other of the parts, when the corresponding lining thickness is small.

[0012] According to an optional feature of the utility model, the torque limiter is a dry torque limiter. The torque limiter is located outside any space containing lubricants (such as grease). Positioning the torque limiter in this way allows dry friction with the organic lining and Belleville spring washer, allowing complete operational control of sliding torque with a minimum axial footprint.

[0013] According to an optional feature of the present invention, at least one radial edge of the annular contact zone is completely bounded by at least one axial gap zone. Both radial edges of the annular contact zone are completely bounded by at least one axial gap zone.

[0014] According to an optional feature of the invention, the torque limiter is fixed to the output element. More specifically, a cover is fixed to the output element. The torque limiter is thus positioned as close as possible to the gearbox, which makes it possible to limit the inertia in front of the torque limiter and thus the excessive torque reaching the torque limiter. According to an optional feature of the invention, the torque limiter comprises two covers, the output element forming one of the two covers. In this way, the number of parts is reduced, thereby reducing the manufacturing costs.

[0015] According to an optional feature of the invention, at least one liner has an axial dimension parallel to the axis of rotation of between 0.2 and 2 millimeters. This dimension is preferably between 0.4 and 1 millimeter. The dimensions of the liner of small thickness are designed to minimize the impact of the liner on the axial footprint of the torque limiter and therefore minimize the impact on the torsional damping device, while performing the function of limiting the solid parts of the torque limiter from rubbing together.

[0016] According to an optional feature of the present invention, at least one axial clearance zone has an axial dimension equal to at least 1.5 times the thickness of the liner.

[0017] According to a feature of the invention, the radial dimensions of the annular contact zone are equal to the radial dimensions of the corresponding liner. As a result of the foregoing, within the meaning of the invention, the axial clearance zone needs to be considered as a deformation forming a recess, which is produced as close as possible to the contact zone against which the liner is pressed.

[0018] According to an optional feature of the invention, the torque limiter comprises two liners in the form of at least partially annular discs surrounding the axis of rotation, the two liners being located on each side of the disc of the torque limiter, the first liner being located between the cover and the disc and the second liner being located between the disc and the pressure plate.

[0019] According to an optional feature of the invention, the elastic element comprises at least one Belleville spring washer between the inner face of the output element and the pressure plate. The Belleville spring washer makes it possible to obtain a height range with very small load variations. This makes it possible to have a torque limiter sliding torque that remains very stable despite the manufacturing tolerances of its components and the wear in operation.

[0020] According to an optional feature of the present invention, the torque limiter is positioned in an axial space defined by an input element and an output element, and the cover of the torque limiter includes a radial accommodating portion arranged perpendicular to the rotation axis and axially facing the disc, and the radial accommodating portion extends a certain distance from the output element so as to define a housing for the disc, the pressure plate, the liner and the elastic element.

[0021] According to an optional feature of the invention, the annular contact zone is radially delimited on each side by two grooves forming respectively an axial clearance zone. The grooves allow the annular contact zone to be raised by thinning the zone radially peripheral to said annular zone. The grooves are realized by bending. Alternatively, the grooves are realized by pressing. Alternatively, the grooves are realized by machining. The grooves are produced on the component to which at least one liner is attached. The grooves are produced on the disc. The grooves are produced on the pressure plate and / or the cover.

[0022] According to an optional feature of the invention, one of the two grooves is located between the annular contact area and the annular peripheral area.

[0023] According to an optional feature of the invention, the annular peripheral zone and the annular contact area have the same radial dimensions.

[0024] According to an optional feature of the invention, the annular peripheral zone and the annular contact zone have the same axial dimensions.

[0025] According to an optional feature of the present invention, the component to which at least one liner is fixed comprises a boss, which forms an annular contact area. The boss is a protrusion formed on the component by deforming the component, to which at least one liner is attached. The protrusion creates an axial offset between the boss and the radial periphery of the component.

[0026] The component is a surface of the cover and / or the pressure plate and is manufactured on the surface of the cover and / or the surface of the pressure plate.

[0027] The component is a disk.

[0028] According to an optional feature of the present invention, the components of the torque limiter are arranged in such a way that the radial receiving portion of the cover, the first liner, the disc, the second liner, the pressure plate and the elastic element are arranged axially continuously.

[0029] According to an optional feature of the invention, two axial clearance zones are formed radially on each side of the annular contact zone.

[0030] According to an optional feature of the invention, at least one axial clearance zone radially delimiting the annular contact zone is formed on the face of the cover and / or on the face of the pressure plate.

[0031] According to an optional feature of the invention, at least one axial clearance zone radially delimiting the annular contact zone is formed on the face of the disk.

[0032] According to an optional feature of the invention, at least one axial clearance zone radially delimiting the annular contact zone is formed on each face of the disk.

[0033] According to an optional feature of the invention, at least one liner is formed from a single annular segment defining an annular contact zone. The segment extends continuously over 360°.

[0034] According to an optional feature of the invention, at least one liner is formed of a plurality of annular segments, a series of annular segments defining an annular contact zone, radial grooves formed on the component to which the liner is fixed being interposed between two consecutive annular segments. Circumferential grooves are also formed on the component to which the liner is attached, the radial and circumferential grooves completely surrounding the segments.

[0035] According to an optional feature of the present invention, the radial groove communicates with at least one axial gap region.

[0036] According to an optional feature of the present invention, the radial groove communicates with an axial gap area formed on each side of the annular contact area.

[0037] According to an optional feature of the present invention, the first liner attached to the cover and the second liner attached to the pressure plate are formed by a plurality of annular segments.

[0038] The utility model also relates to a vehicle transmission system comprising the device.

[0039] The driveline may form part of a vehicle powertrain which may include a hybrid engine or an electric motor, preferably a hybrid engine.

[0040] “Vehicle” is understood to mean a motor vehicle, which includes not only passenger cars but also industrial vehicles, in particular heavy goods vehicles, public transport vehicles or agricultural vehicles, but also any transport unit that is able to move living beings and / or objects from one point to another. BRIEF DESCRIPTION OF THE DRAWINGS

[0041] Other features and advantages of the present invention will become more apparent from the following description and a number of exemplary embodiments, which are provided in a non-limiting manner with reference to the accompanying drawings, in which:

[0042] Figure 1 is a cross-sectional view of a torsional damping device equipped with a torque limiter according to a first embodiment of the present invention, wherein an axial clearance zone is formed around the edge of an annular contact zone through which the liner contacts the pressure plate and the cover;

[0043] Figure 2 yes Figure 1 Detail A of the image makes the axial clearance area more visible;

[0044] Figure 3 yes Figure 1 a cross-sectional view of a torsional damping device of , showing only the pressure plate and the cover and the lining arranged between these parts of the torque limiter, the pressure plate and the cover being located on either side of the disc;

[0045] Figure 4 yes Figure 1 A perspective view of a pressure plate;

[0046] Figure 5 yes Figure 1 A perspective view of the cover;

[0047] Figure 6 is a schematic diagram of an alternative embodiment of a torsional damping device equipped with a torque limiter;

[0048] Figure 7is a schematic diagram of a torsional damping device equipped with a torque limiter according to a second embodiment of the utility model;

[0049] Figure 8 yes Figure 7 A perspective view of a disc equipped with a torsional damping device;

[0050] Fig. 9 is a schematic diagram illustrating the features of the present invention, wherein the annular contact area is bounded by an axial clearance area;

[0051] Fig.10 is a partial perspective view of a disk of a third embodiment in which a liner attached to the disk is formed of an annular segment;

[0052] Fig.11 is a perspective view of a pressure plate and cover of a fourth embodiment in which the liner attached to the disc is formed from annular segments. DETAILED DESCRIPTION

[0053] The features, variants and various embodiments of the present invention can be combined with each other in various combinations, as long as they are not mutually incompatible or mutually exclusive. In particular, variants of the present invention can be envisaged, which only include a selection of the following features, isolated from the other features described, if the selection of such features is sufficient to confer technical advantages and / or distinguish the present invention from the prior art.

[0054] In the figures, elements common to several figures retain the same reference numerals.

[0055] In the following detailed description, the terms "axial" and "radial" refer to the orientation of the torsional damping device according to the present invention and the orientation of the rotation axis around which the various components of the torsional damping device are arranged. The axial direction is parallel to the rotation axis and the radial direction is perpendicular to the rotation axis.

[0056] Figures 1 to 11 A torsional damping device 1 for a vehicle drive train is depicted, the torsional damping device 1 comprising in particular a torque limiter 4 .

[0057] The torsional damping device comprises in particular an input element 6 , an output element 8 and at least one mechanical energy accumulator component, which is interposed between the masses forming the input element and the output element, respectively.

[0058] Both the input element 6 and the output element 8 are rotatable about an axis of rotation X. The input element 6 may be a primary flywheel rotationally fixed to a drive shaft, in this case to a crankshaft (not shown). The input element 6 is fixed to the drive shaft using a first connecting member.

[0059] The output member 8 may in particular comprise a hub 81. The output member 8 may also comprise a mounting plate 82 perpendicular to the rotation axis X. The hub 81 is centered on the mounting plate 82 and has a suitable hole for connecting to a driven shaft (not shown here) which can be used to connect the torsional damping device 1 to a gearbox not shown here.

[0060] like Figure 1 It can be clearly seen in FIG. 8 that the mounting plate 82 for the output element 8 is delimited by a covering element 83 .

[0061] Each mechanical energy accumulator member arranged between the input element 6 and the output element 8 may include a spring 9 configured to resist the pivoting of the input element relative to the output element. The spring 9 may be curved. Alternatively, the spring 9 may be a straight spring. Each spring 9 is alternately connected to the input element 6 and the output element 8 at one end thereof.

[0062] The torsional damping device 1 comprises an annular web arranged so that its periphery is in contact with the spring 9 via the intermediate web 12 as appropriate. The web can transmit torque between the spring 9 and the torque limiter 4. The spring 9 is axially accessible through openings 64, 84 formed in the first input and output elements and is radially held in place by the peripheral edge of the input element 6 and the annular web so that they cannot disengage.

[0063] The torque limiter 4 comprises a disk 10. The disk 10 may coincide with the web just mentioned. The torque limiter may also comprise a cover 14 and a pressure plate 16, as well as friction means or linings 18, 19 arranged between the disk 10 and the cover 14 on the one hand and between the pressure plate 16 and the disk 10 on the other hand. In other words, the torque limiter comprises two linings 18, 19, at least partially in the form of annular disks around the axis of rotation X and located on each side of the disk 10 of the torque limiter. The linings 18, 19 are made of organic material. Alternatively, the linings 18, 19 are based on metal fibers or powders. Alternatively, the linings 18, 19 are coatings, for example thermal coatings.

[0064] The torque limiter 4 also comprises at least one elastic element configured to ensure the axial positioning of the components of the torque limiter relative to each other. The elastic element can notably be constituted by a Belleville spring washer 20 interposed between the inner face of the mounting plate 82 associated with the hub 81 and the pressure plate 16. In the example shown, the elastic element comprises two Belleville spring washers, although this does not limit the invention.

[0065] The cover 14 of the torque limiter comprises a radial housing portion 22 arranged perpendicularly to the rotation axis X and axially facing the disc 10, a fixing portion 24 pressed against the inner face of the mounting plate 82 of the output element 8, and a return portion 26 axially connecting the housing portion 22 to the fixing portion 24 so that the radial housing portion extends a certain distance from the mounting plate 82 of the output element 8 so as to define a housing for the disc 10, the pressure plate 16, the liners 18, 19 and the Belleville spring washer 20.

[0066] The fixing portion 24 is fixed to a mounting plate 82 associated with the hub 81 by a plurality of rivets 26 .

[0067] The torque limiter is axially limited at one axial end by a cover 14 and at the other axial end by a mounting plate 82, and the cover 14 is located between this mounting plate 82, which forms part of the output element 8, on the one hand, and the input element 6 on the other hand. In this way, the torque limiter 4 according to the invention is inside the device, that is to say integrated into the axial space defined by the input element and the output element. The torque limiter is located in the drive train as close as possible to the gearbox, which makes it possible to limit the inertia downstream of the torque limiter and thus to limit the excessive torque reaching those parts of the drive train located between the torque limiter and the vehicle wheels. This architecture also makes it possible to obtain a compact device particularly suitable for the drive train of a hybrid engine.

[0068] like Figure 2 As can be seen more clearly in the figure, the components of the torque limiter 4 except the cover 14 are arranged between the cover 14 and the mounting plate 82, so that the radial receiving portion 22 of the cover 14, the first liner 18, the disk 10, the second liner 19, the pressure plate 16 and the Belleville spring washer 20 are arranged axially continuously.

[0069] The pressure plate 16 , which is rotatable about the axis X, is able to move axially, in particular under the stress exerted by the Belleville washers 20 , so as to move closer to the radial housing 22 of the cover 14 and clamp the disk 10 and the liners 18 , 19 .

[0070] The pressure plate 16 comprises at least one guide tongue 17 projecting radially on its inner periphery and having dimensions adapted to be housed in a notch 27 formed in a return 26 of the cover 14. The cooperation between the guide tongue 17 and the notch 27 allows, on the one hand, a correct angular positioning of the two solid parts of the torque limiter relative to each other and a good transmission of the applicable rotational torque, and, on the other hand, an axial guidance of the pressure plate 16 under the effect of the stress exerted by the Belleville spring washer 20.

[0071] With this arrangement, the first liner 18 is disposed between the inner face 221 of the radial receiving portion 22 of the cover 14 and the first face 101 of the disk 10, and the second liner 19 is disposed between the second face 102 of the disk 10 and the inner face 161 of the pressure plate 16. Arbitrarily, those faces of the cover 14 and the pressure plate 16 that face the disk are referred to as the inner faces.

[0072] The liners 18, 19 are interposed between two rigid parts of the torque limiter, the pressure plate 16 and the disk 10 on the one hand and the cover 14 and the disk 10 on the other hand, so that they are always pressed against one face of the cover 14 or the pressure plate 16 and one face of the disk.

[0073] Each liner is held in place by fixing. The fixing may include bonding, for example using an adhesive, to one of the two rigid parts sandwiching it and firmly pressing against the other of the two rigid parts. Alternatively, the fixing may include riveting, for example using rivets.

[0074] In the event of excessive torque being applied to the torque limiter 4, at least one liner undergoes rotational sliding relative to the rigid part to which it is laterally and to which it is not attached. This sliding occurs because the torque to be transmitted is higher than the internal clamping force of the torque limiter 4.

[0075] As previously mentioned, one or more Belleville washers 20 are axially inserted between the mounting plate 82 associated with the hub 81 of the output element 8 and the pressure plate 16. More specifically, the Belleville washers 20 abut against the face of the pressure plate 16 opposite to the internal face 161 of this pressure plate 16 against which the second liner 19 abuts. This Belleville washers 20 allow the pressure plate 16 to remain pressed against the disk and, despite the possible wear of one of these liners 18, 19, the radial housing 22 of the cover remains pressed against this same disk by pressing on the liners 18, 19 and regulating this pressure. More specifically, each Belleville washers 20 is preloaded so that it constantly applies a predetermined axial pressure to the pressure plate 16, making it possible, on the one hand, to clamp the second liner 19 between this pressure plate 16 and the disk 10, and, since the cover 14 is attached to the mounting plate 82 associated with the hub 81, to clamp the first liner 18 between the disk 10 and the cover 14.

[0076] When the torsional damping device according to the invention is subjected to an axial force greater than the preload force applied to the Belleville spring washer 20, the theoretical separation between the pressure plate 16 and the disk 10 (capable of clamping each liner as described above) is no longer guaranteed, which means that the disk 10 becomes able to rotate frictionlessly relative to the pressure plate 16 and / or the cover 14. The liners 18, 19 and the elements to which they are attached are then free to slide in rotation relative to the elements facing them.

[0077] In particular in the case of internal torque limiters, the thickness of the liners 18, 19 is limited in order to reduce the axial footprint of the torque limiter 4 and therefore of the torsional damping device 1. As a non-limiting example, these liners have a thickness, i.e. an axial dimension parallel to the axis of rotation X, between 0.4 and 1 mm.

[0078] The means according to the invention for fixing the lining 18 , 19 to one of the solid parts of the torque limiter 4 and for limiting the risk of the disc 10 rubbing against the cover 14 or the pressure plate 16 in the event that the lining 18 , 19 does not perform its protective function will now be described in more detail.

[0079] As previously mentioned, each liner 18, 19 is attached to one of the two components interposed therebetween, for example using an adhesive. The liner has an annular overall shape and rests against the components, the liner being interposed between the components in an annular contact zone 50 whose radial dimensions are equal to the radial dimensions of the annular shape of the liners 18, 19. The annular contact zone 50 is Figure 2 and 3 More clearly visible.

[0080] In a first exemplary embodiment of a liner according to the present invention (in Figures 1 to 9 As can be clearly seen in the figure, at least one liner has the form of an annular disk extending continuously around the axis of rotation X. The liner is thus in contact with the component sandwiching it uniformly over the entire periphery of said component. Fig.10 and 11 As shown, in a second exemplary embodiment of a liner, at least one liner 18 , 19 is formed by a plurality of ring segments arranged around the axis of rotation X.

[0081] In each of these two examples, the annular contact zone 50 defined by the contact between the lining and the rigid component of the torque limiter can be considered to be continuous over the entire circumference of the torque limiter 4 .

[0082] According to the invention, one of the solid parts against which the liner 18, 19 abuts is configured so that the face facing the liner 18, 19 is horizontal, so that the annular contact zone 50 for contact between the liner and the solid part is raised and forms a boss relative to the rest of the face comprised by the annular contact zone 50. In other words, when considering the radial direction, one of the solid parts against which the liner abuts has an axial gap 51 on each side of the annular contact zone 50, so that the distance between the two parts located on each side of the relative liner increases.

[0083] In the first embodiment of the invention, the gap and the boss of the annular contact area are achieved by changing the profile of the pressure plate 16 and / or the cover 14. In this first embodiment, the face of the disc 10 in contact with the liner 18, 19 can remain flat.

[0084] Figures 1 to 5 This first embodiment is shown, in which case each of the two annular contact zones 50 associated with the liners 18 , 19 is consistent with what has just been described, i.e. with material having an axial gap 51 on both radial sides, which is intended to increase the distance between the two solid parts of the torque limiter 4 situated on the sides of the associated liner.

[0085] exist Figure 4 The pressure plate 16 is shown in more detail in FIG. 1 , which is formed by a ring on the inner periphery of which the tongue 17 forms a radial protrusion. The annular contact area 50 corresponds to the area against which the second lining 19 abuts and extends over the entire radial dimension of the pressure plate. Figure 3 As shown, an annular contact zone 50 is radially delimited by an axially offset edge, both towards the inside and towards the outside of the pressure plate 16. In this way, an axial gap 51 is created at the edge of the annular contact zone 50, which increases the distance between the pressure plate 16 and the disk 10 that will be located in the torque limiter 4 facing the disk 10. Taking into account the small thickness of the second lining 19 located between this pressure plate 16 and the disk 10, this makes it possible to avoid that the two solid parts come into contact outside the contact zone provided with the lining, for example in the case of flatness defects affecting one or the other. The axial gap 51 can be significantly equal to at least 1.5 times the thickness of the second lining 19. In other words, the axial dimension between the pressure plate and the disk at the axial gap 51 is equal to at least 1.5 times the axial dimension between the pressure plate and the disk at the second lining 19.

[0086] In the example shown, the pressure plate 16 is extruded so that the inner face 161 and the opposite outer face 162, intended to face the disk 10 and to be in contact with the second liner 19, have such an axial offset between the central portion 164 of the pressure plate, in line with the second liner 19, and the edge 166 at the radial periphery. According to what has just been said, the annular contact zone 50 forms a boss and is raised (i.e. axially protruding) relative to the periphery of the pressure plate 16 at the inner face 161, so that the edge 166 at the radial periphery is at a greater distance from the disk 10 than the annular contact zone 50. The outer face 162 of the pressure plate 16, since the plate is made by pressing, has an identical but opposite profile, the edge protruding axially relative to the central portion. In other words, when considering a plane forming the mid-plane of the edge at the periphery of the pressure plate 16, the central portion 164 is offset relative to this plane towards the disk to form this raised annular contact zone 50.

[0087] Therefore, in Figure 4The outer face 162 of the pressure plate 16 visible in FIG. 1 has a hollow in its center, and this recess can form a region for accommodating the Belleville spring washer 20 .

[0088] Alternatively, if Figure 5 As shown, it is possible to envisage only the face of the pressure plate 16 intended to face the disk 10 and to be in contact with the second lining 19 , so that in this case the inner face 161 has the above-mentioned axial offset, while the outer face 162 remains plane.

[0089] More specifically Figure 6 As shown, the cover 14 is configured so that the radial housing 22 has an annular overall shape identical to the annular shape of the pressure plate. The radial housing 22 extends as a vertical continuation of the return 26, so that the free radial end edge 21 of the radial housing 22 can be identified at the end opposite to the return, and the connecting edge 23 of the radial housing 22 can be identified at the junction where the radial housing 22 meets the return 26.

[0090] The annular contact zone 50 corresponding to the zone against which the first lining 18 abuts extends over the entire radial dimension of the radial receiving portion 22 of the cover 14. Figure 3 As shown, an annular contact zone 50 is radially defined by axially offset edges, both towards the inside and towards the outside of the radial housing 22. More specifically, the connecting edge 23 and the free end edge 21 are axially offset relative to the annular contact zone 50. In this way, an axial gap 51 is created, which makes it possible to increase the distance between the radial housing 22 of the cover and the disk 10, facing which the radial housing will be located in the torque limiter. Taking into account the small thickness of the first lining 18 located between the cover 14 and the disk 10, this makes it possible to avoid contact between the two solid parts outside the contact zone provided with the lining, for example in the case of flatness defects affecting one or the other. The axial gap 51 can be significantly equal to at least 1.5 times the thickness of the first lining 18. In other words, the axial dimension between the radial housing of the cover and the disk at the axial gap 51 is equal to at least 1.5 times the axial dimension between the radial housing of the cover and the disk at the second lining 19.

[0091] In the example shown, the cover 14, in particular the radial housing 22, is extruded so that the inner face intended to face the disk 10 and in contact with the first liner 18 and the opposite outer face are provided with this axial offset between the central portion 144 of the radial housing 22 aligned with the first liner 18 and the edge 146 at the radial periphery. According to what has just been said, the annular contact zone 50 forms a boss and is raised (i.e. axially protruding) relative to the periphery of the radial housing 22 of the cover 14 at the inner face 221, so that the edge 146 at the radial periphery is at a greater distance from the disk 10 than the boss forming the annular contact zone 50. The outer face of the radial housing 22 of the cover 14 has an identical but opposite profile, the edge protruding axially relative to the central portion, since the cover is made by pressing. In other words, when considering the plane forming the mid-plane of the edge at the periphery of the radial housing 22 of the cover 14, the central zone is offset towards the disk relative to this plane to form this raised annular contact zone 50.

[0092] According to what has been said about the pressure plate, it is conceivable that, as an alternative, only the face intended to face the disk 10 and to be in contact with the first lining 18 is provided, so that in this case the inner face 221 is provided with the above-mentioned axial offset, while the outer face remains plane. Figure 5 is visible in.

[0093] In the second embodiment of the present invention, Figure 7 As shown, the gap and raised portion in the annular contact area are achieved by changing the profile of the disk 10. In this second embodiment, the surface of the pressure plate 16 and / or cover 14 that contacts the liner can remain flat.

[0094] exist Figure 8 , the disk consists of a ring on the outer circumference of which the retaining arms 28 for retaining the spring 9 form radial projections. The annular contact zone 50 corresponds to the zone against which the lining abuts and extends over a portion of the radial dimension of the disk 10, in this case over approximately half of this radial dimension of the disk. Seen in cross section, for example, Figure 7In the embodiment of the invention, an annular contact zone 50 is delimited radially towards the inside and outside of the disk by axially offset edges, forming an axial gap within the meaning of the invention, more specifically, grooves 31, 32 are formed in the material of the disk 10. Each groove makes it possible to create an axial gap 51 which makes it possible to increase the distance between the disks it will face in the torque limiter. Taking into account the small thickness of the linings 18, 19 positioned against this disk 10, this makes it possible to avoid contact between the disk and the solid part outside the contact zone provided with the lining, for example in the case of flatness defects affecting one or the other. The depth of the grooves can be equal to the thickness of the respective lining 18, 19, so that the axial dimension of the axial gap is at least equal to 1.5 times the axial dimension between the disk and the solid part which helps to clamp the respective lining at this lining.

[0095] In the example shown, the disk 10 is machined or pressed so that at least one face (in this case both faces) includes two grooves defining an annular contact zone. A first groove 31 contributes to forming the peripheral inner edge of the disk, and a second groove 32 separates the annular contact zone 50 from an annular peripheral zone 52 carrying the retaining arm 28. The radial dimensions of this annular peripheral zone 52 are equal to the radial dimensions of the annular contact zone 50, and the second groove 32 is made in the center of the disk.

[0096] According to what has been stated, for at least one face of the disk, the annular contact zone 50 forms a boss and is raised (ie projects axially) relative to the groove 30 defining it. The annular contact zone 50 has a surface extending in the same plane as the surface of the annular peripheral zone 52 .

[0097] Especially in Figure 7 As can be clearly seen in FIG, the disk 10 advantageously has a raised annular contact area 50 on each of these faces 101, 102 (ie for each liner). As an alternative not shown here, it is conceivable that only one face of the disk is provided with the above-mentioned axial offset, while the other face remains flat without machined grooves.

[0098] In each of the embodiments of the invention just described, at least one solid component of the torque limiter is configured to create an axial gap between two mutually facing solid components around an annular contact zone provided with a liner. Fig. 9 The axial gap is shown in more detail, in this case with the pressure plate facing the disc, and with reference to the Fig. 9 Everything described can be applied to each axial gap formed in one of the above-mentioned solid parts.

[0099] In the arrangement of two solid parts of the torque limiter, between which a liner is placed, the annular contact area 50 on the first solid part is thus delimited radially on the pressure plate 16 by two axial gap areas 51 which are axially set back relative to the annular contact area which is thus raised. This results in an axial gap 51 on each side of the annular contact area 50 and which is represented by an axial distance d1 measured between the gap areas formed on the first solid part and the second solid part (in this example the disc 10), which is greater than the shortest axial distance d2 between the two solid parts, i.e. the thickness of the liner, in this example the second liner 19.

[0100] In this way, the risk of contact between the solid parts outside the annular contact zone is limited, therefore without any intervening lining.

[0101] Now refer to Figures 10 to 11 A second exemplary embodiment of the above-described liner is described in more detail. It is noted that the liners in this second exemplary embodiment differ from the liners described previously in that these have a plurality of sectors 34 formed by disk portions arranged around the axis of rotation X. According to the invention, the annular contact zone defined by the contact between each disk portion of the liner and the solid part against which the liner abuts forms a boss which is radially formed with an axial gap on each side of the annular contact zone.

[0102] Fig.10 The understanding of this arrangement is provided in particular in the case of various lining sectors being incorporated into the disk 10. According to what has been described above, the annular contact zone 50 is flanked by two grooves 31, 32, so that a greater axial clearance can be created between the disk 10 and the solid part facing it at the edge of the annular contact zone. The annular contact zone here takes the form of a plurality of bosses, the number of which is equal to the number of lining sectors 34. Each boss is separated from the adjacent boss by a radial groove 36.

[0103] Fig.11 The solid part of the torque limiter 4 is shown again, provided with lining sectors 34 instead of a continuous lining, in which case, in an embodiment, the liners 18, 19 are supported by the pressure plate 16 and the cover 14 instead of by the disk 10. The figure shows in particular the cover and the pressure plate in the assembled position, the guide tongue 17 belonging to the pressure plate 16 engaging in the recess 27 formed in the cover 14.

[0104] The number of inclined lining sectors 34 of the first lining 18 and the second lining 19 is the same, so the number of bosses of the pressure plate 16 formed according to the utility model is the same as that of the cover 14, but it is worth noting that each radial groove 36 formed between two bosses of the cover 14 is axially covered by a boss belonging to the pressure plate 16, and vice versa. As a result of this, at least one lining sector 34 is in contact with the disk 10 over the entire circumference of the torque limiter 4.

[0105] As described above, the present invention achieves its stated purpose, that is, by forming an axial gap on the side of the contact area where the liner is located on at least one of these solid parts, the two solid parts of the torque limiter can be limited from rubbing together in the area without the liner.

[0106] Of course, the present invention is not limited to the examples just described, and various modifications may be made to these examples without departing from the scope of the present invention. Variants not described here may be implemented without departing from the present invention, as long as they include a torque limiter according to the present invention, a part of which supports the liner and is configured to create an axial clearance zone in the immediate vicinity of the liner, thereby locally creating a boss capable of receiving the liner.

Claims

1. A torsional damping device, comprising: an input element (6) configured to be constrained to rotate with the drive shaft about the axis of rotation (X); An output element (8) configured to be constrained to rotate with the driven shaft; and at least one mechanical energy accumulator member (9) arranged between the input element (6) and the output element (8), the torsional damping device also including a torque limiter (4) including a cover (14), a pressure plate (16) and a disk (10), the disk (10) being axially inserted between the cover (14) and the pressure plate (16), the torque limiter (4) also including an elastic element (20) and at least one liner (18, 19), the elastic element (20) being configured to press the pressure plate (16) against the disk (10), at least one liner (18, 19) being arranged between the disk (10) and one of the solid parts being the pressure plate (16) and the cover (14), at least one liner (18, 19) being fixed to the disk (10) or to one of the solid parts, while defining an annular contact area (50), characterized in that the annular contact area (50) is radially bounded by at least one axial gap area (51).

2. The torsional damping device according to claim 1, characterized in that: The torque limiter (4) is fixed to the output element (8).

3. The torsional damping device according to claim 1, characterized in that: The at least one liner (18, 19) has an axial dimension parallel to the axis of rotation (X) between 0.2 mm and 2 mm.

4. The torsional damping device according to claim 1, characterized in that: The annular contact zone (50) is radially delimited on each side by two grooves (31, 32), which respectively form an axial clearance zone (51).

5. The torsional damping device according to claim 1, characterized in that: The component to which the at least one liner (18, 19) is fixed comprises a boss which forms the annular contact zone (50).

6. The torsional damping device according to claim 1, characterized in that: Two axial clearance zones (51) are formed radially on each side of the annular contact zone (50).

7. The torsional damping device according to claim 1, characterized in that: At least one axial gap zone (51) radially delimiting the annular contact zone (50) is formed on the face of the cover (14) and / or on the face of the pressure plate (16).

8. The torsional damping device according to claim 1, characterized in that: At least one axial clearance zone (51) radially delimiting the annular contact zone (50) is formed on the face of the disk (10).

9. The torsional damping device according to claim 1, characterized in that: The at least one liner (18, 19) is formed of a plurality of annular segments (34), a series of annular segments defining the annular contact zone (50), radial grooves (36) formed on the component to which the liner (18, 19) is fixed being interposed between two consecutive annular segments (34).

10. The torsional damping device according to claim 1, characterized in that: The radial grooves (31, 32) are in communication with the at least one axial clearance zone (51).

11. A vehicle transmission system, characterized in that: The vehicle driveline comprises a torsional damping device as claimed in any one of the preceding claims.

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