FR2575532A2 - Torsion damper device with elastic centring member, especially for motor vehicle clutch - Google Patents

Abstract

In this device, two coaxial portions A are mounted rotatably with respect to one another counter to the action of an elastic member 27, which is capable of ensuring the return thereof into a mean rest position, and which, according to the main patent, is a block made from elastic material capable of bearing directly against the corresponding shoulders 32, 33 of the said coaxial portions A. According to an improvement which is a subject of the invention, the elastic member 27 has, in a hollow, in the median zone of each of its circumferential ends, a cutaway. Application, especially, to clutch frictions for motor vehicles.

Description

 There has been described in the main patent a torsional damping device, in particular for the clutching of motor vehicles, of the type comprising at least two coaxial parts mounted to rotate relative to one another, against elastic means interposed circumferentially between they, said for convenience, elastic means with circumferential action, and within the limits of an angular movement determined by means of engagement with clearance provided for this purpose between said coaxial parts, in cooperation with centering means capable of biasing said circumferentially coaxial parts in the direction of an intermediate rest position between the limits of their said angular displacement, said centering means comprising at least one elastic member which, belonging to said elastic circumferential means, is established in the area of the engagement means with play of said coaxial parts and is capable, for the rest position of these, to come into abutment, by each of its circumferential ends, against shoulders of said oblique coaxial parts with respect to each other, this torsion damping device being generally characterized in that said member elastic is a simple block of elastic material, which is circumferentially elongated, substantially tangentially with respect to a circumference of the assembly, and whose circumferential ends, devoid of any coating, are capable of coming to bear directly against said shoulders of said coaxial parts between which it is circumferentially interposed.

 It turns out in fact that, surprisingly., And contrary to the usual provisions in the matter, it is possible to effectively implement, for the constitution of the necessary elastic member, a simple block of elastic material, without this systematically results in a major risk of shearing or tearing for such a block, although it must thus directly cooperate with shoulders formed in practice each by the edge, of necessarily reduced axial extension, of a metal flange.

 This result is all the more surprising since, on the one hand, for at least one of the coaxial parts, the two shoulders with which the two circumferential ends of a block of elastic material must cooperate respectively are oblique relative to each other, like the sides of a dovetail groove, and the result is the presence, in this coaxial part, of relatively sharp beaks each oriented respectively in the direction of the median zone of said circumferential ends, and that, on the other hand, such a block is called in service to work essentially in the dislocation, and is therefore particularly stressed by the shoulders between which it is then engaged.

 The present invention generally relates to various improvements to such a block of elastic material so as to further promote its longevity and or to improve the conditions for intervention in service.

 According to a first of these improvements to the elastic member constituted by such a block of elastic material has, in the hollow, in the median zone of each of its circumferential ends, a clearance.

It follows that, in service, such a block bypasses by its clearance the corresponding spout of the coaxial part having such spouts, without risking being inadvertently injured by it
Its longevity is thus favored.

 According to the other improvements which are the subject of the present invention, arrangements are made to reduce the stiffness of the elastic member constituted by the block of elastic material used.

For example, there is provided for this purpose on at least one of the lateral edges of this block, between the circumferential ends thereof, a recess, so that, in its median zone, such a block has a transverse section reduced section
As a variant, the elastic member constituted by this block of elastic material having indentations as from those of its lateral edges which each extend substantially tangentially relative to a circumference of the assembly, said indentations are circumferentially alternated with one another. relative to the others from one of said edges to the other.

 As a variant, again, the block of elastic material in question comprising, from one to the other of its lateral edges which extend substantially transversely relative to the axis of the assembly, at least one recess which passes through it right through substantially parallel to said axel said recess extends substantially equally on either side of its median plane.

 For example, such a recess may have, over at least a portion of its length, a circular contour, in which case it preferably widens outward at at least one of its ends.

 However, according to a particular embodiment, it has a generally polygonal outline in cross section, the sides close to the edges of the elastic member that constitutes the block of elastic material concerned are substantially parallel to these.

 Such an arrangement is advantageously favorable to a deformation in parallelogram of such a block in service, and this combines in a particularly happy manner with the shear working mode of the latter.

 However, in all cases, recess or recess, it is advantageously possible to reconcile favorably two apparently contradictory subjects, one relating to the very hardness of the block of elastic material used, which it is naturally desirable to be relatively high polish resist as well as possible the stresses of which this block is the object on the part of the shoulders with which it cooperates, the other relating to the stiffness of such a block, of which it can on the contrary be advantageous for it to be relatively minimized, for good filtration of neutral or idle noise.

The characteristics and advantages of the invention will become apparent from the description) which will follow, by way of example, with reference to the appended schematic drawings on which
Figure 1 is a partial elevational view of a torsion damping device according to the invention, according to arrow I in Figure 2, and with a local cutaway;
Figure 2 is an axial sectional view along the broken line II-II of the figure;
Figure 3 is a larger scale, a partial view in cross section along the line III-III of Figure 2, for the rest position of the two coaxial parts concerned;
Figure 4, which partly repeats Figure 3, is a longitudinal sectional view of the elastic centering member used according to the invention in this torsion damping device, shown in isolation
Figure 5 is a cross-sectional view of this elastic centering member, along the line VV of Figure 4
Figure 6 shows, on a larger scale, the detail of Figure 4 identified by a VI insert thereon;
Figure 7 is a view similar to that of Figure 3, for another position of the coaxial parts concerned; ;
Figures 8, 9, 10, 11, 12 are longitudinal sectional views which, all similar to that of Figure 4, each relate respectively to an alternative embodiment of the elastic centering member used in the damping device of torsion according to the invention
Figure 13 is a partial cross-sectional view of the elastic centering member shown in Figure 12, along the line XIII-XIII of Figure 12;
Figure 14 is a cross-sectional view, which, similar to that of Figure 13, relates to an alternative embodiment.

 In Figures 1 to 3, we recognize a torsional damping device of the type described in the main patent: the same elements are designated by the same references.

 In short, this torsion damping device, which is intended to constitute a clutch friction for a motor vehicle clutch, comprises successively rotated two by two with respect to each other, three coaxial parts, namely, part A , constituted by a hub 10, a part B, constituted by a hub web 11 surrounding the hub 10 in the middle part thereof, and a part C, constituted by two guide washers 12, which, each arranged respectively on either side of the hub cover 11, and surrounding it as the hub 10, are linked to each other, from place to place, by axial columns 14 crossing with clearance recesses 15 provided for this purpose in this hub cover 11, and one of which carries a friction disc 16 with a cover 17 and friction linings 20.

 The two coaxial parts A, B are mounted to rotate relative to each other, against elastic means interposed circumferentially between them, called for convenience elastic means with circumferential action, and within the limits of an angular movement determined by backlash means 22.

 For the constitution of these, the hub plate 11 has, on its internal periphery, notches 25 by which it is engaged, with play, on teeth 24 which has the hub 10 radially on its external surface, projecting from a peripheral section 23.

 These play-engaging means 22 are associated with centering means, which are capable of biasing the coaxial parts A, B circumferentially in the direction of an intermediate rest position between the limits of their angular movement, and which comprise at least an elastic member 27 belonging to the elastic means with circumferential action intervening between said coaxial parts A, B.

 In practice, this elastic member 27 forms by itself these elastic means with circumferential action, and it is established in the zone of the interlocking means with clearance 22, in a housing formed by two notches 30, 31 formed, the first, between two teeth 24 of hub 10, and the second, between two notches 25 of hub hub 11.

 These two notches 30, 31 are each delimited, circumferentially, and at each of their ends, by a shoulder, respectively 32, 33.

 For the notch 30, that formed between two teeth 24 of the hub 10, the shoulders 32 are each generally oblique with respect to a radial direction of the assembly passing through their median zone, and they are thus generally oblique one with respect to to the other, approaching each other in the direction opposite to the axis of the assembly, in the manner of the sides of a dovetail groove.

 As will be noted, these shoulders 32 further define each, with the peripheral edge 23 of the hub 10 on which the teeth 24 thereof are projecting, nozzles 34, generally directed circumferentially towards one another, and relatively sharp.

 For the notch 31, that formed between two notches 25 of the hub cover 11, the shoulders 33 generally extend each in a radial direction of the assembly.

 However, taking into account the obliquity of the shoulders 32 of the associated notch 30, the shoulders 32, 33 thus generally forming the circumferential ends of the housing 29 of the elastic member 27 are generally oblique to one another. at each of the circumferential ends of this housing 29, and they therefore form a dihedral.

 As described in the main patent, the elastic member 27 is a simple block made of elastic material, which is generally circumferentially elongated, in the form of a cylinder, substantially tangentially relative to a circumference of the assembly, and whose circumferential ends, devoid of any coating, are capable of coming directly to bear against the shoulders 32, 33 of the coaxial parts A, B between which it is circumferentially interposed, said circumferential ends each forming for this purpose, in hollow, to conform to such shoulders 32, 33, a dihedral, the edge of which extends substantially in the median zone of such a circumferential end.

 Due to the dihedral configuration thus presented by these circumferential ends, the radial maintenance of this block of elastic material is always suitably ensured.

 This is particularly so for the rest configuration of the assembly, .figures 1 and 3, for which, by its circumferential ends, it is engaged with one and the other of the shoulders, or sides of the dovetail notch 30 of hub 10.

 Conjointly, the coaxial parts B, C are themselves rotatably mounted relative to one another, against elastic means interposed circumferentially between them and constituted, in the embodiment shown, by springs 35A, 35B, 35C of the coil spring type, which, according to arrangements described in detail in the main patent, are elongated substantially tangentially to the same circumference of the assembly, being arranged, partly in windows 36A, 36B, 36C of the web of hub 11, and, in part, in windows 37A, 37B, 37C, guide washers 12.

 According to an improvement which is the subject of the present invention, the elastic member 27 has, in the hollow, in the median zone of each of its circumferential ends, a clearance 38.

 In practice, this clearance 38 clears the edge a of the corresponding dihedral.

 In the embodiment shown, this clearance 38 is a generally semi-cylindrical clearance, of generatrices parallel to the axis of the assembly, and it has in cross section a circular contour with an angle at the center O greater than 1800, FIG. 6.

 Furthermore, in the embodiment shown, the cross section of the cylinder formed by the block of elastic material constituting the elastic member 27 is generally quadrangular.

 Longitudinally, this elastic member 27 thus has, parallel to one another, two lateral edges 39, which are generally planar, and which each extend substantially tangentially relative to a circumference of the assembly, and, perpendicular to the above, two lateral edges 40, which are also planar, and which each extend substantially transversely relative to said axis of the assembly, FIGS. 4 and 5.

 In the embodiment shown, at each of the circumferential ends of the elastic member 27, the edges formed by the lateral edges 39 of the latter with the dihedral constituting such a circumferential end are each cut by a chamfer more or less accentuated 41.

 The chamfers 41 thus implemented are intended to promote in operation the obtaining of a suitable support of the elastic member 27 on that then concerned of the circumferential ends of the notch 31 of its housing 29, which are rounded, and they therefore advantageously allow it to avoid being driven radially outwards.

 Preferably, and as shown, such chamfers are provided both at the ends of that of the lateral edges of the elastic member 27 which, tangent to a circumference of the assembly, is radially closest to the axis of the assembly, only at the ends of the one which, also tangent to a circumference of the assembly, is radially farthest from said axis.

 The elastic member 27 can thus advantageously be indifferently placed in one direction or the other.

 In service, when a torque is applied to the coaxial part C, for example in the direction indicated by the arrow F in FIGS. 1, 3 and 7, only the elastic member 27 first elastically yields, until it comes in abutment of the teeth 24 of the hub 10 against the corresponding flank of the notch 25 of the hub cover 11, FIG. 7.

 As will be noted, during such an intervention, the elastic member 27, which works essentially in shearing, is the object of a slight tilting movement, according to arrow F ′ in FIG. 7, around the spout 34 of the hub 10 against which it then bears.

 But, thanks to the clearance 38 which has its corresponding circumferential end, it is spared any punching effect due to this spout 34, for the benefit of its longevity.

 Everything happens as if, by the clearance 38, it bypasses the end of such a spout 34 while remaining in abutment against it, while the said end of this spout 34 penetrates into the said clearance 38.

 when, the increasing torque to be transmitted, the springs 35A, 35B, 35C intervene in their turn, the elastic member 27 remains compressed, and, during an evolution in the opposite direction of this couple, it exerts, between the coaxial parts A , B, a recall request, until these coaxial parts A, B return to their initial average rest position for which their respective shoulders 32, 33 are facing each other.

 In the foregoing, the block of elastic material constituting the elastic member 27 is solid and massive, and its lateral edges 39, 40 flat and smooth.

 Such a block, the hardness of which must be relatively high in order to be able to cooperate directly, without risk of damage, with the shoulders 32, 33 of the coaxial parts A, B, presents, without other, a stiffness like this hardness.

 As a variant, and according to improvements which are the subject of the present invention, arrangements are made to reduce this stiffness.

 For example, in FIG. 8, between its circumferential ends, the elastic member 27 has, on at least one of its lateral edges 39, 40, a recess 42, so that, in its median zone, it has transversely a section reduced section 43.

 In practice, the elastic member 27 thus has a recess 42 on one and the other of those, 39, of its lateral edges which each extend substantially tangentially with respect to a circumference of the assembly.

 In the embodiment shown, such a recess 42, which is of reduced depth P, much less than half the thickness E of the elastic member 27 in its current part, extends over a significant fraction, for example of the order of half, the length of this elastic member 27.

 As a variant, in FIG. 9, the elastic member 27 has, from those 39, its lateral edges which each extend substantially tangentially with respect to a circumference of the assembly, the notches 45, and these notches 45 are circumferentially. alternate with each other from one of said side edges 39 to the other.

 In practice, there are an even number of notches 45 on one of the side edges 39, for example two, and an odd number, for example one, on the other of these.

 In other words, there is a number of notches 45 on one of these lateral edges 39 greater by one unit than the number of notches 45 on the other.

 Despite the alternation of these notches 45, symmetry can thus be preserved for the elastic member 27, with a notch 45 in its median transverse plane for one of its lateral edges 39, which, as before, advantageously makes it possible to put it in place in one direction or the other.

 Preferably, however, that of its lateral edges 39 which has a greater number of notches 45 is the edge radially furthest from the axis of the assembly.

 In the embodiment shown, the notches 45, which are each of reduced width, each have a depth P 'at least equal to half the thickness E of the elastic member 27 in its current part, being for example slightly greater than said half.

 As a variant, FIGS. 10 to 14, the elastic member 27 comprises, from one to the other of those, 40, its lateral edges which extend substantially transversely relative to the axis of the assembly, at at least one recess, which crosses it right through, substantially parallel to said axis, and said recess extends substantially equally on either side of its median plane M.

 In practice, several of such recesses being provided, they each extend substantially equally on either side of the median plane M of the elastic member 27, being substantially aligned along said plane M.

 This median plane M is shown diagrammatically in broken lines by its trace in FIGS. 10, 11.

 In the embodiment more particularly shown in FIG. 10, two recesses 47 are thus provided in the elastic member 27, and these are recesses which have a generally polygonal outline in cross section, being separated one on the other by a right middle partition 48.

 In practice, the sides of such a recess 47 close to the lateral edges 39 of the elastic member 27 are substantially parallel to these, and their sides close to the corresponding circumferential end of this elastic member 27 form a dihedral. like that formed by such a circumferential end.

 In addition, in correspondence with the recess 38 present in hollow at each of the circumferential ends of the elastic member 27, there is projecting inwardly in the recess 47 near such a circumferential end, a boss 49 of contour substantially complementary to that of said clearance 38.

 In other words, apart from that of their sides which is defined by the right middle partition 48, the sides or edges of each of the recesses 47 of the elastic member 27 are each respectively deduced by a simple translation of the corresponding sides or edges of this elastic member 27.

 It follows that, for each of the circumferential ends, the elastic member 27 has at all points the same thickness, and that, similarly, apart from its right median partition 48, it has, along its lateral edges 39, at any point of these, the same thickener.

 In other words, the elastic member 27 is even, both at its circumferential ends and along its lateral edges 39.

 Its molding conditions are thereby favored.

 Anyway, and as shown schematically in broken lines in Figure 10, the recesses 47 which it comprises are also favorable to a deformation in parallelogram of the assembly, which advantageously combines with its shearing work in service .

 Indeed, because the recesses 47 are aligned along the median plane M, only the stiffness is reduced along this median plane M, while, along the side edges 39, it retains its full value.

 In the embodiments shown in FIGS. 11 to 14, two recesses 47 ′ are also provided, but these are recesses which, over at least a portion of their length, have a circular contour, with their axis in the median plane M of the assembly.

 In the embodiment shown in FIG. 11, the recesses 47 ′ thus have the same section throughout their length.

 As a variant, FIGS. 12 to 14, they will widen outwards at least at one of their ends, and in practice at each of these, ie, FIGS. 12, 13, only before contour holes. circular of greater diameter 50 are provided at each of said ends, or, in FIG. 14, that these are before tapered holes 501.

 Thanks to recesses thus staged, a certain progressiveness of the stiffness can be obtained.

 -Of course, the present invention is not limited to the embodiments described and shown, but encompasses any variant and / or combination of their various elements.

 In addition, and as shown in solid lines in Figures 9, 11, the chamfers 41 may be relatively accentuated, or, as shown in solid lines in Figures 4, 8, 10 and 12, and as shown schematically in broken lines in Figure 11, they can be relatively erased.

 Furthermore, it goes without saying that by "elastic material", we refer here to a visco-elastic material, in practice.

rubber or an elastomer.

Claims (18)

 1. A torsion damping device, in particular for a motor vehicle clutch, of the type comprising, according to claim 1 of the main patent, at least two coaxial parts (A, B) mounted so as to rotate relative to one another, at l 'against elastic means interposed circumferentially between them, called for convenience elastic means with circumferential action, and within the limits of an angular displacement determined by means of engagement with clearance (22) provided for this purpose between said coaxial parts (A , B), in cooperation with centering means suitable for circumferentially biasing said coaxial parts (A, B) in the direction of an intermediate rest position between the limits of their said angular movement, said centering means comprising at least one member elastic (27) which, belonging to said elastic circumferential means, is established in the area of the interlocking means with clearance (22) of said coaxial parts (A , B) and is capable, for the rest position thereof, of coming to bear, by each of its circumferential ends, against shoulders (32, 33) of said coaxial parts (A, B) oblique one by relative to the other, and which is a simple block of elastic material circumferentially elongated, substantially tangentially with respect to a circumference of the assembly, the circumferential ends of which, devoid of any coating, are capable of coming to bear directly against said shoulders (32, 33) of the coaxial parts (A, B) between which it is circumferentially interposed, characterized in that, in the median zone of each of its circumferential ends, said elastic member (27) has, in hollow, -a clearance (38).  2. A torsion damping device according to claim 1, characterized in that, each of the circumferential ends of the elastic member (27) forming, in hollow, a dihedron, the corresponding clearance (38) recesses the edge of said dihedron.  3. Torsion damping device according to any one of claims 1, 2, characterized in the shell the clearance (38) is a generally semi-cylindrical clearance of generatrices parallel to the axis of the assembly.  4. Torsion damping device according to claim 3, characterized in that the clearance (38) has in cross section a circular contour with an angle at the center (O) greater than 1800.  5. Torsion damping device, in particular for a motor vehicle clutch, of the type comprising, according to claim 1 of the main patent, at least two coaxial parts (A, B) mounted so as to rotate relative to each other, to the against elastic means interposed circumferentially between them, called for convenience elastic means with circumferential action, and within the limits of an angular movement determined by means of engagement with clearance (22) provided for this purpose between said coaxial parts (A, B), in cooperation with centering means capable of circumferentially biasing said coaxial parts (A, B) in the direction of an intermediate rest position between the limits of their said angular movement, said centering means comprising at least one elastic member (27) which, belonging to said elastic circumferential action means, is established in the area of the play-engagement means (22) of said coaxial parts (A, B) and is capable, for the rest position thereof, of coming to bear, by each of its circumferential ends, against shoulders (32, 33) of said coaxial parts (A, B) oblique to one another to the other, and which is a simple block of elastic material circumferentially elongated, substantially tangentially with respect to a circumference of the assembly, the circumferential ends of which, devoid of any coating, are capable of coming to bear directly against said shoulders (32 , 33) of the coaxial parts (A, B) between which it is circumferentially interposed, characterized in that, between its circumferential ends, the elastic member (27) has, on at least one of its lateral edges, a recess (42), so that, in its median zone, it has transversely a section of reduced section (43).  6. Torsion damping device according to claim 5, characterized in that said recess (42), of reduced depth (P), much less than half the thickness (E) of the elastic member (27) extends over a substantial fraction of the length of said elastic member (27).  7. Torsion damping device according to any one of claims 5, 6, characterized in that the elastic member (27) has a recess (42) on one and the other of those (39) of its edges lateral which each extend substantially tangentially with respect to a circumference of the assembly.  8. Torsion damping device, in particular for a motor vehicle clutch, of the type comprising, according to claim 1 of the main patent, at least two coaxial parts (A, B) mounted so as to rotate with respect to each other, at l 'against elastic means interposed circumferentially between them, called for convenience elastic means with circumferential action, and within the limits of an angular movement determined by play engagement means (22) provided for this purpose between said coaxial parts ( A, B), in cooperation with centering means suitable for circumferentially biasing said coaxial parts (A, B) in the direction of an intermediate rest position between the limits of their said angular movement, said centering means comprising at least one elastic member (27) which, belonging to said elastic circumferential action means, is established in the area of the play-engagement means (22) of said coaxial parts ( A, B) and is capable, for the rest position thereof, of coming to bear, by each of its circumferential ends, against shoulders (32, 33) of said oblique coaxial parts (A, B) one relative to the other, and which is a simple block of elastic material circumferentially elongated, substantially tangentially relative to a circumference of the assembly, the circumferential ends of which, devoid of any coating, are capable of coming to bear directly against said shoulders (32, 33) of the coaxial parts (A, B) between which it is circumferentially interposed, characterized in that, the elastic member (27) having notches (45) counting from those (39) of its lateral edges which each extend substantially tangentially relative to a circumference of the assembly, said notches (45) are circumferentially alternating with respect to one another from one of said lateral edges (39) to the other.  9. A torsion damping device according to claim 8, characterized in that said notches (45) which are each of reduced width, each have a depth (P ') at least equal to half the thickness (E) of l elastic member (27) *  10. Torsion damping device according to any one of claims 8, 9, characterized in that, there is an even number of notches (45) on one of the lateral edges (39) concerned of the elastic member (27) and an odd number on the other of these.  11. Torsional damping device, in particular for the clutch of a motor vehicle, of the type comprising, according to claim 1 of the main patent, at least two coaxial parts (A, B) rotatably mounted relative to one another, at l 'against elastic means interposed circumferentially between them, called for convenience elastic means with circumferential action, and within the limits of an angular displacement determined by means of engagement with clearance (22) provided for this purpose between said coaxial parts (A , B), in cooperation with centering means suitable for circumferentially biasing said coaxial parts (A, B) in the direction of an intermediate rest position between the limits of their said angular movement, said centering means comprising at least one member elastic (27) which, belonging to said elastic means with circumferential action, is established in the region of the play-engaging means (22) of said coaxial parts ( A, B) and is capable, for the rest position thereof, of coming to bear, by each of its circumferential ends, against shoulders (32, 33) of said oblique coaxial parts (A, B) one relative to the other, and which is a simple block of elastic material circumferentially elongated, substantially tangentially relative to a circumference of the assembly, the circumferential ends of which, devoid of any coating, are capable of coming to bear directly against said shoulders (32, 33) of the coaxial parts (A, B) between which it is circumferentially interposed, characterized in that, the elastic member (27) comprising, from one to the other of those (40) of its lateral edges which extend substantially transversely to the axis of the assembly, at least one recess (47, 47 ') which passes right through it substantially parallel to said axis, said recess (47, 471) s' extends substantially equally on both sides re of the median plane (M) of said elastic member (27).  12. Torsion damping device according to claim 11, characterized in that, several recesses (47, 47 ') being provided, they each extend substantially equally on either side of the median plane (M) of the elastic member 127), being substantially aligned along said plane (M)  13. Torsion damping device according to any one of claims 11, 12, characterized in that a recess (47) has in cross section a generally polygonal contour whose sides close to the edges of the elastic member (27) are substantially parallel to these  14.Torsion damping device according to any one of claims 12, 13, characterized in that, each of the circumferential ends of the elastic member (27) forming, in hollow, a dihedral, the sides of a recess (47 ) close to such a circumferential end also form between them a dihedral like the previous one.  15. A torsion damping device according to claims 1 and 11, taken together, characterized in that, in correspondence with the clearance (38) that each of the circumferential ends of the elastic member (27) has in hollow, there are, projecting inwardly into the recess (47) near such an end, a boss (49) whose contour is substantially complementary to that of said clearance (38).  16. A torsion damping device according to any one of claims 11 to 15, characterized in that, two recesses (47), only, being provided, they are separated from each other by a straight middle partition (48 )  17. Torsion damping device according to any one of claims 11, 12, characterized in that, a recess (47 ') having, over at least a portion of its length, a circular contour, it widens towards the outside at at least one of its ends.  18. Torsion damping device according to any one of claims 1 to 17, characterized in that, at the ends of at least one of the lateral edges of said elastic member (27) which extend substantially tangentially to a circumference of the 'together, the edges of said elastic member (27) are each knocked down by a chamfer (41).