FR2803640A1 - Synchronizing assembly for an automotive vehicle transmission includes an arrangement between two synchronizing rings, which has a central part cooperating with a reciprocally shaped part of the synchronizing unit - Google Patents

Abstract

The assembly includes an arrangement (16) between two synchronizing rings (10), which especially has a central part (23) cooperating with a reciprocally shaped part (26) of the synchronizing unit (2) for exerting a radial force ensuring that the synchronizing rings are at their inactive position. The central part of the arrangement (16) includes two elastic bands (23) connecting respectively to the two lateral branches and is elastically supported, in the inactive position, respectively on the two opposed flanks of the reciprocally shaped form for exerting on it a radial supporting force.

Description

The present invention relates to a synchronizer assembly for a transmission of an automobi vehicle. It is known that the operation of a synchronizer consists of several phases starting from the neutral phase of the transmission and comprising the arming phase, the phase of synchronization and interconnection phase. To this end, the known synchronizer assembly comprises a synchronization hub secured to a driven shaft; a clutch sleeve mounted on the synchronization hub in mesh with the latter and which can be moved axially relative to the synchronous hub by a control fork two synchronization rings located on each side of the synchronization hub two transmission pinions with toothed crowns of interconnection mounted swiveling on the driven shaft and each axially spaced from the corresponding synchronization ring which can be engaged friction with the corresponding transmission pinion during an axial displacement of the clutch sleeve; an arming means which can be moved axially the clutch sleeve when the latter moves towards its engagement position with the carburetted ring.

Thus, during the synchronization phase, synchronization rings generate, under a low axial force, a high friction torque. However, this friction torque becomes harmful in particular during the neutral phase, for example during vibrations applied to the gearbox, the synchronization rings can be moved axially in a direction of production of the friction torque.

The present invention aims to eliminate the above drawback by proposing a synchronizer assembly for a transmission of an automobi vehicle of the type comprising a synchronization hub secured to a driven shaft; a clutch sleeve mounted on the synchronization hub meshing with the latter and being able to be moved axially relative to the synchronization hub by a control fork two synchronization rings located on each side of the synchronization hub; two transmission pinions with toothed crown sprockets mounted to rotate on the driven shaft and each axially spaced from the corresponding synchronization ring which can be engaged by friction with the corresponding transmission pinion during an axial movement of the clutch sleeve; and an arming means which can be moved axially by the clutch sleeve when the latter moves towards its engagement position with the clutch crown, and which is characterized in that the arming means is housed between two synchronization rings and comprises two positively opposite lateral branches respectively connected to the two synchronization rings and a central part cooperating with a conjugate form of the synchronization hub to exert radial force for axially maintaining the synchronization rings in the neutral position.

According to a first embodiment, the central part of the arming means comprises two elastic strips connected respectively to the two lateral branches by being elastically supported, in neutral position, respectively on the two opposite flanks of the conjugate form to exercise this- ci the radial holding force.

The conjugate shape can be a projecting part in the form of an inverted V or, alternatively, a re-entrant part in the form of a V.

Each lateral branch of the arming means comprises a flange substantially at right angles engaged in the conjugate groove of the corresponding synchronization ring.

The two elastic strips of the arming means are connected respectively to the two flanges of the arming means. The arming means comprises an upper connecting part of the two lateral branches, engaging in a conjugate recess of the clutch sleeve so as to drive axially. the arming means when moving the clutch sleeve to its engagement position with the corresponding clutch ring.

The arming means is produced by folding thin sheet metal plate.

According to a second embodiment, the arming means comprises a housing having two outer edges substantially at right angles defining the two lateral branches and which are respectively engaged in two grooves of the two synchronization rings in which is housed a helical compression spring s 'extending transversely to the driven shaft and pressing the central part of the arming means, on the conjugate form of the synchronization hub.

According to an alternative embodiment, the central part is a ball pressed by the spring at the bottom of a cavity constituting the approximately hemispherical conjugate shape of the synchronization hub.

The ball is housed at the bottom of the housing by partially projecting therefrom.

According to another alternative embodiment, the conjugate form is a projecting part in the form of an inverted V and the central part is a part provided with a recess of a form conjugate with the projecting part.

The housing has its open upper part in which protrudes a second ball elastically supported by the helical spring in the approximately hemispherical cavity of the clutch sleeve so as to drive the arming means when the sleeve is moved to its position. meshing with the corresponding clutch gear.

According to a third embodiment, the arming means comprises an elongated housing parallel to the driven shaft and the two lateral walls of which are spaced apart longitudinally and have their lower ends projecting from the housing bottom wall so as to define the two lateral branches. which are engaged respectively in two grooves two synchronization rings, and two elastic blades housed in the housing being inclined relative to each other to define, in cross section the shape of a V and connected together by a part making protruding from below the bottom wall of the housing and defining the central part of the arming means so that the two blades exert on the central part the radial force allowing the rings to be kept synchronized in their neutral position.

The two blades extend longitudinally in the housing and are braced at the upper wall of the housing to exert on the central part the radial force directed towards the driven shaft.

The arming means has its upper wall engaging in a recess of conjugate shape of the clutch sleeve so as to axially drive the arming means during the movement of this sleeve in its engagement position with the corresponding clutch crown .

The invention will be better understood, and other objects, characteristics, details and advantages thereof will appear more clearly in the explanatory description which follows, made with reference to the appended schematic drawings given solely by way of example illustrating three modes of embodiment of the invention and in which - FIG. 1 shows in upper longitudinal half-section the synchronizer assembly comprising the arming means according to a first embodiment of the invention making it possible to maintain the two synchronization rings axially during transmission neutral phase; - Figure 2 is a perspective view of the arming means used in the synchronizer assembly of figure; - Figure 3 is an alternative embodiment of arming of Figures 1 and 2; - Figure 4 is a view similar to that of the figure of the synchronizer assembly comprising the arming means according to a second embodiment of the invention and making it possible to maintain two synchronization rings axially; - Figure 5 is an alternative embodiment of arming means of Figure 4; - Figure 6 is a view similar to that of the figure of the synchronizer assembly comprising an arming means according to a third embodiment for axially holding the two synchronization rings and - Figure 7 is a perspective view of the means d arming of figure 6.

referring to FIGS. 1 and 2, the synchronizer assembly 1 for a transmission of a motor vehicle comprises a synchronization hub 2 integral in rotation with a driven shaft 3 by means of splines 4. The synchronization hub 2 is immobilized in translation on the shaft 3 on the one hand by a stop ring 5 mounted in an external peripheral groove of the shaft 3 and on the other hand by a radial face of one, the one on the left relative to FIG. 1, of two transmission pinions 6 mounted idly on the shaft 3 on either side of the synchronization hub 2. The synchronizer assembly 1 also includes a clutch sleeve 7 which can be moved axially, that is to say ie parallel to the shaft 3, by a control fork (not shown) engaged in a radially outer groove 8 of the sleeve 7 which has internal grooves (not shown) ensuring the engagement of the sleeve 7 on the periphery of the hub of synchronization 2 while allowing axial displacement of the sleeve 7 relative to the hub 2.

The synchronizer assembly 1 further comprises two identical internally conical synchronization rings 10 located on either side of the synchronization hub 2 adjacent to it and which can each be moved axially towards the corresponding transmission pinion 6, to engage by friction the synchronization ring 10 with the transmission pinion 6. Each synchronization ring 10 has an externally toothed part as indicated in 11.

The synchronizer assembly 1 also comprises on each side of the synchronization hub 2 two other concentric frustoconical synchronization rings which can be engaged one in the other by friction during the displacement in the corresponding direction of the clutch sleeve 7 and comprising respectively the synchronization ring 12 for coming into friction contact in the synchronization ring 9 and the synchronization ring 13 being able to engage by friction in the ring 12.

Each transmission pinion 6 comprises an externally toothed clutch gear 14 on which the clutch sleeve 7 can mesh. The two transmission pinions 6 are immobilized in translation relative to the shaft 3 by two extreme stop rings 15 mounted respectively in two external grooves of the shaft 3. The synchronizer assembly comprises at least one arming means 16 which can be moved axially by the clutch sleeve 7 in a determined direction, causing the axial displacement of the corresponding synchronization rings 10, 12, 13 in order to engage them by friction with a conjugate frustoconical bearing Gal of a central part forming a hub 6a of the corresponding transmission pinion 6. Advantageously, it will be noted that the synchronizer assembly is provided with three arming means 16 distributed angularly at regular intervals.

The synchronizer assembly described above generally corresponds to the synchronizer assembly described in French patent application No. 99 09 667 filed July 26, 1999 in the name of the applicant.

According to the invention, the arming means 16, as can be seen more clearly from FIG. 2, is produced by folding a sheet of thin sheet metal so as to comprise two parts forming lateral branches connected to each other by an upper connecting part 18 comprising a planar wall 19 connected to two planar walls 20 of the two branches 17 respectively by means of two planar walls 21 inclined in opposite directions to one another. The two walls 20 of the lateral branches 17 are located in the same plane below the plane containing the upper wall 19 while being parallel to the latter.

Each lateral branch 17 fitting means 16 also includes a flange 22 extending at right angles to the corresponding wall 20 below the latter, the flange 22 being folded back so as to define in cross section a U shape with a flat bottom. .

The arming means 16 further comprises two elastic strips 23 located in the central part of the arming means and connected respectively to the two lateral branches 17. More precisely, the two strips 23 are inclined towards one another to define V-shaped, the branches of which are connected to their upper parts to the corresponding branches respectively of the two U-shaped parts of the lateral branches 17 by means of two flat walls situated below the two flat walls parallel to the latter.

two elastic strips 23 are not connected to their lower parts and have two lower edges facing each other, each defined by a folded part situated in a plane perpendicular to the upper wall 19.

The upper part 18 of the arming means 16, which has in cross section, with its walls 19, 21 the shape of a trapezoid, preferably isosceles, is engaged in a recess of conjugate shape 25 machined in the clutch sleeve 7 and the two elastic strips 23 defining the central part of the arming means are resiliently in support, in neutral position respectively on two inclined faces of a V-shaped groove obtained directly from the sintered stock in the synchronization hub 2 and extending transversely to the shaft 3. In addition, the two U-shaped flanges 22 of the two lateral branches 17 of the arming means 16 are respectively engaged in two grooves of conjugate shapes 27 machined in the two synchronization rings 10 and extending transversely to the shaft 3.

Thus, in the neutral position, the two elastic strips 23 exert a radial elastic force directed towards the driven shaft 3 allowing the arming means 16 to hold the two synchronization rings 10 axially via the flanges 22 engaged in the respective grooves 27 of the two synchronization rings 10, which makes it possible to reduce the halftone at the level of the synchronization rings. When the clutch sleeve 7 is moved axially in one direction or the other by the control fork, it moves axially in the same direction axially 16, whose corresponding flange 22 moves the ring in the same direction. associated synchroni ion 10, as well as the two other adjacent synchronizing rings 12, 13 to bring them into friction contact with each other and bring friction ring 13 to the frustoconical bearing 6a1 of the corresponding transmission pinion 6. The interconnection sleeve 7 then meshes successively with the teeth 11 of the synchronization ring 10 and the toothed ring 14 of the transmission pinion 6, then resulting in a rotation of the hub 2, of the sleeve 7, of the synchronization rings 10,, 13 or pinion 6.

Of course, the movement of the clutch sleeve 7 takes place against the elastic restoring force exerted by the strips 23 of the arming means 16 which are then each elastically pushed radially away from the driven shaft 3 by the inclined wall of the V-shaped groove 26 of the hub 2.

According to an alternative embodiment, the synchronization hub 2 comprises a projecting part 'in the shape of an inverted "V" as visible in FIG. 3, obtained directly from the crude sintered material. In the neutral position, the arming means 16 cooperates via the two elastic blades 23 with the sides of the "V" of the projecting part, thus ensuring indexing in such a position and maintaining the synchronization rings 10.

According to the second embodiment shown in Figure 4, where the parts of the synchronizer assembly shown therein and identical to those already described with reference to the synchronizer assembly of Figures 1 and 2, have the same references, the means armament 16 comprises a housing 28 housed between the synchronization rings 10, 12 and 13 and extending perpendicular to the driven shaft 3. This housing comprises two opposite parallel outer flanges 29, folded at right angles to the shaft 3 so as to define two lateral branches which respectively engage in two grooves 30 of the two synchronization rings 10. The two grooves 30, like the grooves 27 in the previous embodiment, are parallel and extend in a direction perpendicular to the driven shaft, that is to say perpendicular to the plane of FIG. 4.

A helical compression spring is housed in the housing 28 transversely to the shaft 3 and has its lower turn resting on a ball 32 partly protrudes from the bottom of the housing 28 so as to be pressed by the spring 31 in a cavity conjugate shape 33 approximately hemispherical of hub 2.

The spring 31 has its upper turn in contact with a second ball of larger diameter which projects from the housing 28 at the upper part thereof and is pressed by the spring 31 into a cavity of conjugate shape 35 approximately hemispherical of the clutch sleeve 7.

In the neutral position of the synchronizer assembly, the spring 31 exerts on the lower ball 32 a radial force directed towards hub 2 so that the arming means maintains by its lateral branches 29, the two synchronization rings in the axially fixed position. . When the dog clutch sleeve 7 is moved axially in one direction or another to carry out the dog clutch phase, it moves the housing 8 of the arming means 16 in the corresponding direction, via the 34, so that the ball lower 32 is returned elastically, against the return force of the spring 31 in a radial direction opposite to the shaft 3 and the corresponding synchronization ring 10 is moved in the same direction by the associated lateral branch 29 arming means 16.

According to an alternative embodiment, the synchronization hub 2 has a projecting portion in the form of an inverted V as visible in FIG. 5 obtained in the rough state. In the neutral position, the arming means 16 cooperates by means of a sintered part 32a provided with a recess 32b of shape conjugated to the projecting part 33 'with the latter.

According to the third embodiment shown in Figures 6 and 7 and wherein the parts identical to those of the previous embodiments have the same references, the arming means 40 comprises elongated housing 41 located between the two synchronization rings 10 and extending parallel to the driven shaft 3. The housing comprises two longitudinally spaced side walls 42 arranged perpendicular to the driven shaft 3 and connected to each other by an upper connecting wall 43 engaging in a recess of conjugate shape 25 of the clutch sleeve 7 so as to allow the arming means 40 to be moved by the clutch sleeve 7 in a direction parallel to the driven shaft 3. As shown in FIG. 6, the connecting wall 43 of the side walls 42 has a central part having, in cross section, the shape of an isosceles trapezium whose sides are respectively connected to two pa flat rties 44 connected to the respective side walls 42. The two side walls 42 have their lower ends projecting below the bottom wall of the housing 41 so as to engage respectively in two grooves 46 of the synchronization rings 10.

arming means 40 further comprises two elastic blades 47 housed in the housing 41 being inclined in opposite directions to each other and connected together by a central part 48 projecting from below the bottom wall 45 of the latter so as to be resiliently supported in the conjugate recess 26 of the synchronization means 2 by the radial force directed towards the driven shaft 4 exerted by the two elastic blades 47 on the central part 48. The blades 47 extend longitudinally in the housing and are braced, by their two upper free ends, under the upper wall of the housing 41 and central part 48 at its projecting end having in cross section the shape of a V conjugate has 1 recess 26 of the hub 2.

During a movement of the clutch sleeve 7 towards one of the transmission pinions 6, the sleeve 7 drives in the same direction the arming means 40 so as to move the corresponding synchronization ring 10 concomitantly. During this movement , the central part 48 is moved radially in the opposite direction to the driven shaft 3 by the corresponding inclined wall of the conjugate recess 26 hub 2 against the restoring force of the two elastic blades 47.

The two blades 47 and the central part 48 thus make it possible to maintain two synchronization rings 10 in the neutral position.

The arming means which are the subject of each of the three embodiments described above makes it possible to prevent the synchronization rings from moving axially, for example during vibrations, and thus to prevent generating a slight friction torque. synchronization rings on top of each other. The synchronizer assembly makes it possible to combine the advantage of an arming system serving first speed side and second speed side or third side and fourth speed side without having the disadvantages of systems known at the time. return to neutral since the arming means is designed to prevent arming on the opposite side when returning to neutral.

Claims (4)

<U> CLAIMS </U> 1. Synchronizer assembly for a transmission of a motor vehicle, comprising a synchronization hub (2) integral with a driven shaft (3); a clutch sleeve (7) mounted on the synchronization hub (2) meshing with the latter and which can be moved axially relative to the synchronization hub (2) by a control fork; at least two synchronization rings (10) located on each side of the synchronization hub (2) two transmission pinions (6) with dog clutch crowns (14) mounted journalled on the driven shaft (3) and each axially spaced from the corresponding synchronization ring which can be engaged by friction with the corresponding transmission pinion (6) during axial movement of the clutch sleeve (7); and an arming means (16; 40) which can be moved axially by the clutch sleeve (7) when moving the latter towards its engagement position with the clutch ring (14); characterized in that the arming means (16; 40) is housed between the two synchronization rings (10) and comprises two opposite lateral branches (17; 29; 42) positively connected respectively to the two synchronization rings (10) and a central part (23 32 48) cooperating with a conjugate shape (26; 33) of the synchronization hub (2) to exert a radial force allowing the synchronization rings (10) to be held in the neutral position. 2. synchronizer assembly according to claim, characterized in that the central part of the arming means (16) comprises two elastic strips (23) connected respectively to the two lateral branches (17) being resiliently in support, in neutral position , respectively on the two opposite sides of the conjugate form to exert on it the radial holding force. 3. Synchronizer assembly according to claim 2, characterized in that the conjugate shape is a re-entrant part (26) in a V shape. 4. Synchronizer assembly according to claim 2, characterized in that the conjugate form is a protruding part (26 ') in the form of an inverted V. Synchronizer assembly according to one of the preceding claims, characterized in that each lateral branch (17) of the cocking hub () comprises a flange substantially at right angles (22) engaged in a conjugate groove (27) of the corresponding synchronization ring (10). . Synchronizer assembly according to claim 5, characterized in that the two elastic strips (23) are connected respectively to the two flanges (22) of the arming means (16). Synchronizer assembly according to one of the preceding claims, characterized in that the fitting means (16) comprises an upper part (18) connecting the two lateral branches (17) engaging in a conjugate recess (25) of the clutch sleeve (7) so as to axially drive the arming means (16) during movement of the clutch sleeve (7) to its engagement position with the corresponding clutch ring. Synchronizer assembly according to one of the preceding claims, characterized in that the arming means (16) is produced by folding a thin sheet metal plate. . Synchronizer assembly according to claim 1, characterized in that the arming means (16) comprises a housing (28) having two outer edges substantially at right angles (29) defining the two aforementioned lateral branches and which are engaged respectively in two grooves (30) of the two synchronization rings (10) and in which is housed a helical compression spring (31) extending transversely to the driven shaft (3) and pressing the central part (32) of the arming means on the conjugate form (33, 33 ') of the synchronization hub (2). 10. Synchronizer assembly according to claim 9, characterized in that the central part is a ball (32) plate by the spring (31) at the bottom of an approximately hemispherical cavity (33) constituting the conjugate form synchronization hub. 11. Synchronizer assembly according to claim 10, characterized in that the ball (32) is housed at the bottom of the housing (28) by projecting partially outside thereof. 12. Synchronizer assembly according to claim 9, characterized in that the conjugate form is a projecting part (33 ') in the form of an inverted V and the central part is a part (32a) provided with a recess) of form conjugate to the projection (33 '). 13. Synchronizer assembly according to one of claims 9 or 12, characterized in that the housing (28) has its open upper part in which protrudes a second ball (34) resiliently supported in support of the helical spring (31) in a cavity approximately hemispherical (35) of the clutch sleeve) so as to drive the arming means when the sleeve moves to its engagement position with the corresponding clutch crown. 14. Synchronizer assembly according to claim 1, characterized in that the arming means 0) comprises an elongated housing (41) parallel to the driven shaft (3) and the two side walls of which are longitudinally spaced (42) have their ends projecting from the bottom wall (45) of the housing) so as to define the two lateral branches which are respectively engaged in two grooves (46) of the two synchronization rings (10), and two elastic blades (47) housed in the housing (41) being inclined 1 relative to one another to define, in cross section, the shape of a V and connected together by a part '(48) projecting from below the bottom wall (45) of the housing (41) and defining the central part of the arming means (40) so that the two blades (47) exert on the central part (48) the radial force allowing the maintenance of the synchronization rings (10 ) at their position we are in neutral. 15. The assembly of claim 14, characterized in that the two blades (47) extend longitudinally in the housing (41) and are braced the upper wall of the housing (41) to exert on the central part the radial force directed towards the driven shaft (3). 16. The assembly of claim 14 or 15, characterized in that the arming means (40) has its upper wall (43) engaging in a conjugate-shaped recess (25) of the clutch sleeve (7) so axially driving the arming means (40) during movement of the clutch sleeve (7) to its engagement position with the corresponding clutch ring (14).