FR3068420B1 - ROTARY DEVICE EQUIPPED WITH A TARGET - Google Patents

Abstract

The invention relates to a device (1) for a motor vehicle transmission chain comprising: - a rotary element (3) intended to be mounted in rotation around an axis of rotation X, the rotary element (3) comprising a cylindrical skirt (8) of axial orientation; a target (2) intended to be arranged facing a sensor capable of delivering a signal representative of the angular position and / or the speed of the target (2), the target (2) being fixed on the element rotary device (3) and having an annular ring (17) which extends axially and is arranged circumferentially around the cylindrical skirt (8) of the rotary member (3), the annular ring (17) having fingers (18) which extend parallel to the X axis and separate from each other windows (19, 21) distributed about the X axis, each finger (18) having a distal end (20); and - a protection ring (22) which is fixed to the rotary element (3), said protective ring (22) comprising an internal bearing portion (23) positioned radially between the distal end (20) of the fingers (18) and the cylindrical skirt (8) so that the distal end (20) of each finger (20) is able to bear radially inwards on said internal support portion in order to limit the deformation of the annular ring (17).

Description

Rotary device equipped with a target

TECHNICAL FIELD The invention relates to the field of motor vehicle transmission chains and more particularly relates to a device of a motor vehicle transmission chain which is equipped with a target intended to be arranged facing a sensor.

Technological background

Document DE102008023869 discloses a primary flywheel of a double damping flywheel equipped with a target. The target comprises a radially oriented flange which is fixed against the cover of the primary flywheel and a plurality of fingers which extend axially from the outer periphery of the flange, all around a cylindrical skirt of the primary flywheel. Thus, when the double damping flywheel is rotated, the fingers generate magnetic field variations that can be detected by a sensor disposed opposite the target. Such a sensor is thus able to deliver a signal representative of the angular position and / or the speed of the target. The distal end of each of the fingers bears against an annular boss which projects radially outwardly of the cylindrical skirt of the primary flywheel. This makes it possible to prevent the fingers from deforming radially inwards, for example during transport of the primary flywheel. However, such an arrangement is not completely satisfactory. In particular, the formation of the annular boss on the cylindrical skirt of the primary flywheel requires a machining operation of the primary flywheel which is expensive, and all the more so if it is desired to obtain a radially external rib of the boss which is precise so to guarantee a suitable arrangement of the boss with respect to the end of the fingers. summary

An idea underlying the invention is to propose a device for a motor vehicle transmission chain, equipped with a target intended to be arranged opposite a sensor which is of simple manufacture and in which the risks of deformation of the target are limited.

According to one embodiment, the invention provides a device for a motor vehicle transmission chain comprising: a rotary element intended to be rotatably mounted about an axis of rotation X, the rotary element comprising a cylindrical skirt axial orientation; a target intended to be arranged opposite a sensor capable of delivering a signal representative of the angular position and / or the speed of the target, the target being fixed on the rotary element and comprising an annular ring which is extends axially and is disposed circumferentially around the cylindrical skirt of the rotary member, the annular ring having fingers which extend parallel to the X axis and separate from each other the windows distributed around the X axis, each finger having a distal end; and a protective ring which is fixed to the rotary element, said protection ring comprising an internal bearing portion positioned radially between the distal end of the fingers and the cylindrical skirt so that the distal end of each finger is adapted to bear radially inwards on said inner bearing portion to limit deformation of the annular ring.

Thus, the protection of the fingers of the target is provided by a protective ring which is separate from the rotating element, which facilitates the manufacture of the device.

According to other advantageous embodiments, such a device may have one or more of the following characteristics.

According to one embodiment, the distal ends of the fingers are in contact against the inner bearing portion of the protection ring.

According to another alternative embodiment, the distal ends of the fingers are separated radially from the internal bearing portion by a functional clearance less than a radial distance which may cause plastic deformation of the fingers. This facilitates the mounting of the target and / or the protective ring on the rotating element while limiting the irreversible deformations of the annular ring. By way of example, the functional clearance is less than 1 mm, for example of the order of 0.5 mm.

According to one embodiment, the protection ring further comprises an outer bearing portion the inner and outer bearing portions being respectively disposed radially on either side of the distal end of the fingers. This makes it possible to limit the radial deformations of the fingers in both directions.

According to one embodiment, the protection ring comprises a plurality of openings each receiving the distal end of one of the fingers, the outer bearing portion and the inner bearing portion being constituted respectively by the outer edges. and the inner edges of the openings.

According to one embodiment, the openings are formed in a radially oriented portion of the protection ring.

According to one embodiment, the protection ring comprises an axially oriented portion which extends in a direction opposite to the annular ring from a radially outer edge of the openings. This makes it possible to limit the radial size of the protection ring.

According to one embodiment, the protection ring further comprises an axial protection portion, which projects radially outwards with respect to the internal bearing portion and is arranged axially opposite the distal end of the fingers. . Advantageously, the axial protection portion protrudes radially beyond the fingers.

According to one embodiment, the outer bearing portion and the inner bearing portion are connected to each other by the axial protection portion.

According to one embodiment, the axial protection portion has a toothing for driving in rotation of the rotary element. In other words, the protection ring also provides a ring gear function for rotating the rotary element, which limits the number of components of the device.

According to one embodiment, the protective ring is force-fitted into a shoulder formed in an edge of the cylindrical skirt.

According to another embodiment, the protective ring is fixed by welding or riveting on the rotary element.

According to one embodiment, the protection ring is obtained by bending a steel bar, welding end-to-end its ends and optionally machining said bar.

According to another embodiment, the protective ring is a stamped sheet metal part.

According to one embodiment, the rotary element is a flywheel, such as a primary flywheel of a torsion damper.

According to one embodiment, the distal end of the fingers is welded to the protection ring. This makes it possible to limit the radial and circumferential deformations of the fingers.

According to one embodiment, the rotary element comprises a radial portion having an outer periphery and the cylindrical skirt extends axially from the outer periphery of the radial portion.

According to one embodiment, the target or the protective ring has a lid portion which extends radially and is disposed against one end of the cylindrical skirt which is opposite to the radial portion of the rotary member, the portion forming lid defining, with the cylindrical skirt and the radial portion of the rotary member, an annular chamber.

Such an annular chamber may in particular be intended for housing elastic members when the device is a torsion damper. The elastic members may in particular be helical springs or elastic blades. Such resilient blades are attached to one of the primary and secondary members of the torsion damper and have a camming surface that cooperates with a cam follower associated with the other member. Such torsion dampers are described in particular in documents FR3027986, FR3026801 and FR3032248.

According to a particular embodiment, the device further comprises: a web which is rotatable relative to the rotary element and which is interposed axially between the lid portion and the radial portion of the rotary element; and - resilient members, such as helical springs, which are housed in the annular chamber and which are each interposed circumferentially between a bearing lug integral with the veil and a bearing seat integral in rotation with the rotary member .

According to one embodiment, each bearing seat integral in rotation with the rotary element has two opposite lugs respectively formed in the radial portion of the rotary element and in the lid portion of the target or the ring. protection.

According to one embodiment, the target is made in a metal sheet. Thus, the annular ring generates magnetic field variations that can be detected. The metal sheet is for example steel.

According to one embodiment, the target comprises a flange which has a radial orientation, the annular ring extending axially from an outer periphery of the flange, the distal end of the fingers being opposite to the flange.

According to one embodiment, the flange is fixed, for example by welding, against one end of the cylindrical skirt of the rotary element which is opposite to the radial portion of the rotary element. The flange thus forms a lid defining with the radial portion and the cylindrical skirt of the rotary member, an annular chamber.

According to one embodiment, the protective ring is made in one piece.

According to one embodiment, the protection ring is made of several segments. The realization of the protection ring in several segments reduces the amount of sheet metal required for the manufacture of the protective ring.

According to another embodiment, the flange is fixed against the radial portion of the rotary member.

BRIEF DESCRIPTION OF THE DRAWINGS The invention will be better understood, and other objects, details, features and advantages thereof will become more clearly apparent from the following description of several particular embodiments of the invention, given solely for the purposes of the invention. illustrative and not limiting, with reference to the accompanying drawings. - Figure 1 is a rear perspective view of a torsion damper equipped with a target and a protective ring according to a first embodiment. FIG. 2 is a half-sectional view of the torsion damper of FIG. 1. FIG. 3 is a perspective view of the target of the torsion damper of FIG. 1. FIG. a perspective view of the protection ring of the torsion damper of FIG. 1. - FIG. 5 is a partial sectional view of a torsion damper equipped with a target and a protective ring according to a second embodiment. - Figure 6 is a partial sectional view of a torsion damper equipped with a target and a protective ring according to a third embodiment. - Figure 7 is a partial rear view in perspective of a torsion damper equipped with a target and a protective ring according to a fourth embodiment. FIG. 8 is a sectional view of the torsion damper of FIG. 7. FIG. 9 is a partial rear view of a torsion damper equipped with a target and a protective ring according to a fifth embodiment. FIG 10 is a partial sectional view of the torsion damper of Figure 9. - Figure 11 is a partial rear view of the protective ring of the torsion damper of Figures 9 and 10. - The figure 12 is a partial sectional view of a torsion damper equipped with a target and a protective ring according to a sixth embodiment. - Figure 13 is a partial sectional view of a torsion damper equipped with a target and a protective ring according to a seventh embodiment. - Figure 14 is a partial sectional view of a torsion damper equipped with a target and a protective ring according to an eighth embodiment. - Figure 15 is a partial sectional view of a torsion damper equipped with a target and a protective ring according to a ninth embodiment. - Figure 16 is a partial sectional view of a torsion damper equipped with a target and a protective ring according to a tenth embodiment. - Figure 17 is a partial sectional view of a torsion damper equipped with a target and a protective ring according to an eleventh embodiment. - Figure 18 is a rear perspective view of a torsion damper equipped with a target and a protective ring according to a twelfth embodiment. FIG. 19 is a perspective front view of the target of the torsion damper of FIG. 18; FIG. 20 is a half-sectional view of a torsion damper equipped with a target and a protection ring according to a twelfth embodiment. Fig. 21 is a rear view of the torsion damper protection ring of Fig. 20. Fig. 22 is a partial sectional view of a torsion damper according to a fourteenth embodiment.

Detailed description of embodiments

In the description and the claims, the terms "external" and "internal" as well as the "axial" and "radial" orientations will be used to denote, according to the definitions given in the description, elements of the device. By convention, the "radial" orientation is directed orthogonally to the axis X of rotation of the device determining the "axial" orientation and, from the inside towards the outside while moving away from said axis, the "circumferential" orientation "is directed orthogonally to the axis of the device and orthogonal to the radial direction. The terms "external" and "internal" are used to define the relative position of one element relative to another, with reference to the axis X of rotation of the device, an element close to the axis is thus qualified as internal as opposed to an outer member located radially periphery. Furthermore, the terms "rear" AR and "front" AV are used to define the relative position of one element relative to another in the axial direction, an element intended to be placed close to the engine being designated by the rear and an element intended to be placed close to the gearbox being designated by before.

With reference to FIGS. 1 and 2, there is a device 1 of a transmission chain which is equipped with a target 2 intended to be arranged facing a sensor, not shown. The sensor makes it possible to deliver a signal representative of the angular position and / or the speed of the target 2. Such a sensor is in particular able to inform the vehicle computer of the position of the crankshaft, which enables the vehicle computer to control properly fuel injection and, for gasoline engines, spark plugs.

In Figures 1 and 2, the device 1 is a torsion damper. The latter comprises a primary element 3 and a secondary element 4 which are mounted so as to be rotatable relative to each other about the axis X. The torsion damper also comprises elastic members 5, illustrated in FIG. 2, which are arranged to transmit a torque and dampen the rotation acyclisms between the primary element 2 and the secondary element 3. The primary element 3 is here a primary flywheel intended to be fixed at the end of a crankshaft d 'a motor. As illustrated in FIG. 2, it comprises a hub 6, a radial portion 7 which extends radially outwardly from the hub 6 and a cylindrical skirt 8 of axial orientation which extends forward from the periphery external part of the radial portion. The primary element 3 is provided with orifices, illustrated in FIG. 1, allowing the passage of fastening screws, not shown, intended for fastening the primary element 3 to the crankshaft of the engine. The primary element 3 also comprises a cover 9, in particular illustrated in FIG. 2, fixed on the front end of the cylindrical skirt 8. The cover 9 defines with the radial portion 7 and the cylindrical skirt 3, an annular chamber 10 in which are housed the elastic members 5. The resilient members 5 are, for example, curved coil springs which are circumferentially distributed about the axis X. Each of the elastic members 5 extends circumferentially between two support legs of a sail 11 integral in rotation with the secondary element 4 and two support seats carried by the primary element 3.

Each support seat carried by the primary element 3 is, for example, constituted by two bosses 12, 13 which are respectively formed in the radial portion 7 of the primary element 3 and in the cover 9. The bosses 12 formed in the radial portion 7 of the primary element 3 are shown in Figure 1 while the bosses 13 formed in the cover 9 are shown in Figure 3.

Thus, in operation, each of the elastic members 5 is supported, at a first end, against a support seat carried by the primary element 3 and, at a second end, against a support lug, not shown, carried by the web 11, so as to ensure the transmission of torque between the primary element 3 and the secondary element 4.

According to an alternative embodiment not illustrated, the web 11 is not directly attached to the secondary element 4 but is rotatable about the X axis relative to said secondary element 4. In this case, the torque is transmitted between the web 11 and the secondary element 4 by one or more additional stages of elastic members. The secondary element 4 is here a secondary flywheel intended to form the reaction plate of a clutch, not shown, connected to the input shaft of a gearbox. The secondary element 4 is centered and guided on the primary element 3 by means of a bearing 14, such as a rolling bearing with ball bearings, as represented in FIG. 2.

Furthermore, the primary element 3 is equipped with a ring gear 15 for driving in rotation of the primary element 3, using a starter. The ring gear 15 is here attached by welding against the front face of the cover 9. The torsion damper is further equipped with a target 2 as shown in detail in FIG. 3. The target 2 comprises a flange 16 which has a radial orientation. In the embodiment shown in Figure 2, the flange 16 is fixed against the front end of the cylindrical skirt 8 and forms the cover 9 of the primary element 3. The flange 16 thus comprises the bosses 13 which are each suitable to form, with a lug 12 facing in the radial portion 7 of the primary element 3, a bearing seat for the elastic members 5.

Furthermore, the target 2 comprises an annular ring 17 which extends axially rearwards from the outer periphery of the flange 16. The annular ring 17 comprises a plurality of fingers 18 which extend in the axial direction, parallel to the X-axis and which are separated from each other by windows 19. In the embodiment shown, the distal ends 20 of the fingers 18 are free, that is to say are not connected to each other. However, in other embodiments, not shown, the annular ring 17 has a distal edge opposite the flange 16, which has an annular shape and provides a connection between the distal ends 20 of the fingers 18.

Such a structure formed of an alternation of fingers 18 and windows 19 allows a sensor, which is fixed on the vehicle frame and is positioned radially opposite the annular ring 17, to detect the position and / or the speed of the vehicle. the target 17.

In an advantageous embodiment, the target 2 is made of a magnetic material. The target 2 is for example made in a metal sheet, preferably steel. In addition, the sensor is able to detect magnetic field variations. Such a sensor is for example an active sensor with hall effect or a passive sensor. Thus, the alternation of fingers 18 and windows 19 of the annular ring 17 is adapted to generate, when the target is rotated, a magnetic field variation that is detected by the sensor.

In another embodiment, the sensor is an optical sensor that detects the passage of a window 19 or a finger 18 in its optical field.

Advantageously, at least one of the windows, referenced 21 in FIGS. 1 and 3, has a circumferential dimension different from that of the other windows 19. Such a window 21 constitutes a reference point for determining the angular position of the target 2 Alternatively, such a mark may also be formed by a finger 18 having a dimension in the circumferential direction greater than that of the others.

Furthermore, the torsion damper comprises a protective ring 22 which is fitted on the cylindrical skirt 8 of the primary element 3 and which aims to protect the annular ring 17, and more particularly its fingers 18 against deformations that might degrade the accuracy of the signal delivered by the sensor.

As shown in FIG. 2, the cylindrical skirt 8 has a shoulder, formed in the rear edge of said cylindrical skirt 8, and in which the protective ring 22 is mounted. The protective ring 22 has a bearing portion internal 23 which is located radially inside the fingers 18, and more particularly between the distal end 20 of said fingers 18 and the cylindrical skirt 8.

According to one embodiment, the distal end 20 of each of the fingers 18 is in contact against the internal bearing portion 23 of the protection ring 22. This makes it possible to limit the deformation of the annular ring 17, and more particularly fingers 18, radially inwards in case of shocks. However, such a structure requires a force assembly of the target 2 with respect to the protection ring 22.

According to another variant embodiment, each of the distal ends 20 of the fingers 18 is separated from the internal bearing portion 23 by a functional clearance less than a radial distance which can cause plastic deformation of the fingers 18. The functional clearance is typically less than 1 mm, for example of the order of 0.5 mm.

Furthermore, the protection ring 22 also comprises an axial protection portion 24. The axial protection portion 24 is constituted by an annular bead which protrudes radially outwards with respect to the internal bearing portion 23 and which is located axially facing the distal end 20 of the fingers 18. Thus, this axial protection portion 24 protects the fingers 18 against impacts in the axial direction. Advantageously, the outer end of the axial protective portion 24 is located at a radial distance from the X axis equal to or greater than that of the outer surface of the fingers 18.

According to one embodiment, the protective ring 22 is obtained by bending a steel bar so that its two ends can be welded end-to-end and then machining the steel bar and bent.

According to one embodiment, the protective ring 22 is secured to the primary element 3 by tight fitting, for example by hot fitting, in the shoulder formed in the rear edge of the cylindrical skirt 8.

In another embodiment shown in FIG. 13, the protection ring 22 is welded to the primary element 3, for example, between the inner periphery of the protection ring 22 and the axially oriented surface of the protective ring 22. shoulder formed in the cylindrical skirt 8 of the primary element 3.

Moreover, according to another embodiment shown in FIG. 14, the distal end 20 of the fingers 18 is welded against the protection ring 22. Such a weld 26 thus makes it possible to limit the radial or circumferential deformations of the fingers 18. The weld 26 can be made between the distal end 20 of the fingers 18 and the axial protection portion 24, as shown in FIG. 14, or between the distal end 20 of the fingers 18 and the internal support portion 23.

The embodiment of FIG. 15, which does not represent the invention, is a degraded version of the embodiment of FIGS. 1 to 4. In this embodiment, the protection ring 22 does not comprise a portion of internal support 23 capable of protecting the fingers 18 against radial inward deformations and comprises only an axially oriented portion 24 which lies axially opposite the distal end 20 of the fingers 18 and which thus makes it possible to protect the fingers 18 against the impacts in the axial direction.

The embodiment of FIG. 16 differs from the embodiment of FIGS. 1 to 4 in that the protection ring 22 has only an internal support portion 23 and no axial protection portion 24. If such an embodiment protection ring 22 is easier to manufacture, it does not provide protection of the fingers 18 against the impacts in the axial direction.

The embodiment of FIG. 22 differs from the embodiment of FIGS. 1 to 4 in that the protection ring 22 also performs the function of a ring gear intended to drive the primary element 3 to rotate in rotation. using a starter. In this case, the toothing 36 is formed in the axial protection portion 24 which protrudes radially outwards with respect to the internal bearing portion 12 and is thus axially opposite the distal end 20 of the fingers 18. .

The embodiment of FIG. 5 differs from that described above in relation to FIGS. 1 to 4 in that the protection ring 22 furthermore comprises an outer support portion 25. The external support portion 25 is disposed radially outside the distal ends 20 of the fingers 18 such that said distal ends 20 of the fingers 18 are disposed radially between the outer bearing portion 25 and the inner bearing portion 23. Thus, such a ring of protection 22 limits the radial deformations of the fingers 18 in both directions, that is to say radially outwardly and radially inwards. In the embodiment shown, the outer bearing portion 25 projects radially forwardly from the axial protection portion 24. Such an outer bearing portion 25 may, for example, be obtained by folding the radially outer edge of the axial protection portion 24 or by machining the protection ring 22 so as to provide an annular housing for receiving the distal end 20 of the fingers 18, the housing being defined by the internal bearing portion 23, the axial protective portion 24 and the outer bearing portion 25. The outer bearing portion 25 allows in particular to limit the deformation of the fingers 18 to the outside under the effect of centrifugal forces during the rotation of the damper .

The embodiment of FIG. 6 differs in particular from that described above in relation to FIGS. 1 to 4 in that the protection ring 122 is here produced by stamping a metal sheet. The protective ring 122 comprises a first cylindrical portion 126 of axial orientation intended to be mounted on the axially oriented portion of the shoulder formed in the rear edge of the cylindrical skirt 8. The protective ring 122 also comprises a first radially oriented portion 127 which extends radially outwardly from the front end of the first cylindrical portion 126 and abuts against the radially oriented surface of the shoulder formed in the rim rear of the cylindrical skirt 8. The protective ring 122 further comprises a second cylindrical portion of axial orientation. This second axially oriented portion 123 extends axially rearwardly from the outer edge of the first radially oriented portion 127. The second axial orientation portion 123 forms an internal bearing portion which is located radially at the inside of the fingers 18 and which limits the deformation of the fingers 18 radially inwardly. Finally, the protection ring 122 comprises a second radially oriented portion 124 which projects radially outwardly from the rear end of the second axially oriented portion 123. This second radially oriented portion 124 forms the axial protective portion for protecting the fingers 18 against impacts in the axial direction. The protective ring 122 may be made in one piece or in several segments. The production of the protection ring 122 in several segments makes it possible to reduce the quantity of sheet metal required for the manufacture of the protective ring 122. The segments of the protection ring 122 may be fixed on the portion of axial orientation the shoulder formed in the rear edge of the cylindrical skirt 8 through a weld.

Figures 7 and 8 show a torsion damper according to another embodiment. In this embodiment, the elements of the protection ring 222 which are identical or fulfill the same function as those of FIG. 6 are referenced with the same number increased by 100. As in the embodiment of FIG. protection ring 222 is made of a metal sheet. In this embodiment, the protection ring 222 comprises a cylindrical portion of axial orientation 226 and a portion of radial orientation 227. The cylindrical portion of axial orientation 226 is intended to be mounted against the axial orientation portion of the shoulder formed in the edge of the cylindrical skirt 8. The radially oriented portion 227 protrudes radially outwardly from the front end of the cylindrical portion of axial orientation 226 and abuts against the surface of the radial orientation of the shoulder formed in the cylindrical skirt 8. The radially oriented portion 227 comprises a plurality of openings 229 each receiving the distal end 20 of a respective finger 18. Thus, as in the embodiment of FIG. 5, the distal ends 20 of the fingers 18 are disposed between an internal support portion 223 and an external support portion 225 which are constituted respectively by the internal edges of the openings 229 and by their external edges, which makes it possible to limit the radial deformations of the fingers in both directions. In addition, the circumferentially opposite edges of the openings make it possible to maintain an orientation of the fingers 18 parallel to the X axis.

In such an embodiment, the protective ring 222 may in particular be attached to the primary element 3 by press fitting or by welding.

Figures 9, 10 and 11 show a torsion damper according to yet another embodiment. In this embodiment, the elements of the protection ring 322 which are identical or fulfill the same function as those of FIGS. 7 and 8 are referenced with the same number increased by 100. In the embodiment of FIGS. The protective ring 322 has a radially oriented portion 327 having apertures 329 in which the distal ends 20 of the fingers 18 are accommodated. However, in this embodiment, the radially oriented portion 327 is axially extended toward the rearwardly by an axially oriented portion 332 from the radially outer edge of the openings 329. Thus, such an arrangement allows this embodiment to have a smaller radial size than the previous embodiment of Figures 7 and 8.

Furthermore, in this embodiment, the protection ring 322 comprises a radial orientation fixing portion 330 which is pressed against the radial orientation portion 7 of the primary element 3 and which is fixed thereto. , for example by a weld 31. The radial orientation portion 327 and the radial orientation fixing portion 330 are here connected to each other by a substantially frustoconical portion 333. The torsion damper of FIG. 12 differs from that described above in relation with FIGS. 9, 10 and 11 only in that the fixing portion 430 of the protection ring 422 is not secured to the primary element 3 by welding but by riveting. In this embodiment, the elements of the protection ring 422 which are identical or fulfill the same function as those of FIGS. 7 and 8 are references with the same number increased by 100. The protection ring 422 is fixed on the element primary by means of rivets 34 which are formed in the mass of the primary element 3 and which pass through orifices formed in the fixing portion 430 of the protection ring 422. In another embodiment not shown, the rivets 34 are not formed in the mass of the primary element 3 and pass through both openings in the radial portion 7 of the primary element 3 and in the attachment portion 430 of the ring protection 422.

As in the embodiment of FIG. 6, the protection rings 222, 322 and 422 of the embodiments of FIGS. 7 and 8, 9 to 11, and 12 can be made in several segments.

Figures 17 to 19 illustrate a torsion damper according to another embodiment. In this embodiment, the axial positions of the target 2 and the protection ring 522 are reversed with respect to their positioning of the embodiments described above. Thus, the protection ring 522 has a radial orientation portion 537 which forms the cover 9 of the primary element 3. The radially oriented portion 537 is fixed against the front edge of the cylindrical skirt 8. In addition, in such an embodiment, the inner portion of radial orientation 537 has bosses, not shown, which are each adapted to form, with a boss 12 facing in the radial portion 7 of the primary element 3, a seat support for elastic members 5.

The flange 16 of the target 2 is fixed against the radially oriented portion 7 of the primary element 3 and the annular ring 17 extends axially forwards from the outer periphery of the flange 16. The flange 16 is fixed by riveting against the radial orientation portion 7 of the primary element 3. As shown in Figures 17 to 19, the flange 16 has holes 40 allowing the passage of rivets 39 through said flange However, the flange 16 may also be attached to the primary element 3 by any other means. As in the previous embodiments, the annular ring 17 comprises a plurality of fingers 18 separated from each other by windows 19. The protection ring 522 comprises a portion of axial orientation 538 which extends rearwardly from the outer periphery of the radial orientation portion 537. The axially oriented portion 538 is disposed around the cylindrical skirt 8 of the primary member 3. The rear end of the axially oriented portion 538 extends radially between the distal end 20 of each of the fingers 18 and the cylindrical skirt 8 of the primary element 3. The portion of axial orientation 538 thus forms an internal bearing portion 523 intended to limit the deformation of the fingers 18, radially inwards in case of shocks.

Figures 20 and 21 illustrate a torsion damper according to another embodiment. In this embodiment, the elements of the protection ring 622 which are identical or fulfill the same function as those of FIGS. 17 to 19 are referenced with the same increased number of 100. This embodiment differs from the embodiment of FIGS. at 19 that the protective ring 622 has at the rear end of the axially oriented portion 538 a radially oriented portion 641 which is provided with openings 629 housing the distal ends 20 of the fingers 18 in a similar manner FIG. 21 illustrates, in particular, bosses 613 which are formed in the radially oriented portion 637 of the protective ring 622 forming the cover 9 and which are each able to form, with a boss 12 facing in the radial portion 7 of the primary element 3, a bearing seat for the elastic members 5.

As for the embodiment shown in FIG. 14, the protection ring 222, 322, 422 and 622 of the embodiments of FIGS. 7 and 8, 9 and 11, 12 and that of FIGS. 20 and 21 make it possible to limit circumferential deformations of the fingers 18.

Although the invention has been described in connection with several particular embodiments, it is obvious that it is not limited thereto and that it comprises all the technical equivalents of the means described and their combinations if they are within the scope of the invention.

In particular, if the invention has been described above in connection with a torsion damping device, a target as described above can also be associated with other types of device, such as a flywheel rigid or flexible, a torque converter or the like. The use of the verb "to include", "to understand" or "to include" and its conjugated forms does not exclude the presence of other elements or steps other than those set out in a claim.

In the claims, any reference sign in parentheses can not be interpreted as a limitation of the claim.

Claims (13)

Device (1) for a motor vehicle transmission chain comprising: - a rotary element (3) intended to be rotatably mounted around an axis of rotation X, the rotary element (3) comprising a cylindrical skirt ( 8) axial orientation; a target (2) intended to be arranged facing a sensor capable of delivering a signal representative of the angular position and / or the speed of the target (2), the target (2) being fixed on the element rotary device (3) and having an annular ring (17) which extends axially and is arranged circumferentially around the cylindrical skirt (8) of the rotary member (3), the annular ring (17) having fingers (18) which extend parallel to the X axis and separate from each other windows (19, 21) distributed about the X axis, each finger (18) having a distal end (20); and - a protection ring (22, 122, 222, 322, 422, 522, 622) which is attached to the rotary member (3), said protective ring (22, 122, 222, 322, 422, 522, 622) having an inner bearing portion (23, 123, 223, 323, 423, 523, 623) positioned radially between the distal end (20) of the fingers (18) and the cylindrical skirt (8) so that that the distal end (20) of each finger (20) is adapted to bear radially inwards on said internal bearing portion in order to limit the deformation of the annular ring (17). 2. Device according to claim 1, wherein the distal ends (20) of the fingers (18) are in contact against the inner bearing portion (23, 123, 223, 323, 423, 523, 623) of the ring. protection device (22, 122, 222, 322, 422, 522, 622) or radially separated from the internal bearing portion by a functional clearance less than a radial distance that can cause plastic deformation of the fingers (18). 3. Device according to claim 1 or 2, wherein the protective ring (22, 222, 322, 422, 622) further comprises an outer bearing portion (25, 225, 325, 425, 625) portions internal and external support being respectively arranged radially on either side of the distal end (20) of the fingers (18). 4. Device according to claim 3, wherein the protective ring (22, 222, 322, 422, 622) comprises a plurality of openings (229, 329, 429, 629) each receiving the distal end (20). of one of the fingers (18), the outer bearing portion (225, 325, 425, 625) and the inner bearing portion (223, 323, 423, 623) being respectively constituted by the outer edges and the internal edges of the openings (229, 329, 429, 629). 5. Device according to any one of claims 1 to 3, wherein the protective ring (22) further comprises an axial protective portion (24), which projects radially outwardly relative to the portion of internal support (23) and is arranged axially facing the distal end (20) of the fingers (18). 6. Device according to claim 5 taken in combination with claim 3, wherein the outer bearing portion (25) and the inner bearing portion (23) are connected to each other by the protective portion. axial (24). 7. Device according to claim 5 or 6, wherein the axial protective portion (24) has a toothing (36) for driving in rotation of the rotary member (3). 8. Device according to any one of claims 1 to 7, wherein the protective ring (22, 122, 222, 322, 422) is force-fitted into a shoulder formed in an edge of the cylindrical skirt (8). . 9. Device according to any one of claims 1 to 8, wherein the protective ring (22, 322, 422) is fixed by welding or riveting on the rotary member (3). 10. Device according to any one of claims 1 to 9, wherein the distal end (20) of the fingers (18) is welded to the protective ring (22). 11. Device according to any one of claims 1 to 10, wherein the rotary member (3) comprises a radial portion (7) having an outer periphery and wherein the cylindrical skirt (8) extends axially from the periphery. outer portion of the radial portion (7). The device according to claim 11, wherein the target (2) or the protective ring (522, 622) has a cover portion (16, 537, 637) which extends radially and is disposed against an end of the cylindrical skirt (8) which is opposed to the radial portion (7) of the rotary member (3), the cover portion (16, 537, 637) defining with the cylindrical skirt (8) and the radial portion (7). ) of the rotary member (3) an annular chamber (10). 13. Device according to claim 11, further comprising: - a web (11) which is rotatable relative to the rotary member (3) and which is interposed axially between the cover portion (16, 537, 637). and the radial portion (7) of the rotary member (3); and - resilient members (15) which are housed in the annular chamber (5) and which are each interposed circumferentially between a bearing lug integral in rotation with the web (11) and a bearing seat integral in rotation with the rotary element (3).