FR2975455A1 - SYNCHRONIZATION UNIT OF A GEARBOX - Google Patents

Abstract

The invention relates to a synchronization unit (12) of a gearbox (10), comprising a synchronizing body (14) rotatably mounted on a gearbox shaft, an arranged sliding sleeve (18). secured in rotation with respect to the synchronizing body (14) but axially displaceable, a synchronization ring (22) for coupling the synchronization body (14) to a gear wheel of the gearbox (10) by means of a link friction, and a locking wedge synchronization assembly (26) which engages the sliding sleeve (18) and biases the synchronizing ring (22) with an axial gear shift force (F) against the pinion coupling speed during axial displacement of the sliding sleeve (18), the locking wedge synchronization assembly (26) having a synchronizing slider (28) and a locking slider (30). Supporting surfaces (56a, 56b, 58a, 58b) which are adapted to engage on corresponding opposing surfaces (60a, 60b, 62a, 62b) of the synchronization body (14) are formed on the locking slide ( 30), the bearing and / or opposing surfaces (56a, 56b, 58a, 58b, 60a, 60b, 62a, 62b) being inclined at least in portions such that a force (F) acting in the peripheral direction (16) between the locking slider (30) and the synchronizing body (14) causes an axial force component (F) which urges the synchronization ring (22) against the speed gear to be coupled.

Description

Transmission synchronization unit The invention relates to a synchronization unit of a gearbox, comprising a synchronization body mounted to rotate with a gearbox shaft, a sliding sleeve arranged rotatably arranged. relative to the synchronizing body but axially displaceable, a synchronization ring for coupling the synchronization body to a transmission speed gear by a friction connection, and a locking wedge synchronization assembly which engages on the sliding sleeve which biases the synchronizing ring with an axial shift force against the speed gear to be coupled during axial displacement of the sliding sleeve, the locking wedge timing assembly having a synchronizing slide and a blocking slide. Such synchronization units are for example known from the generic document DE 2007 010 307 B3 and are in particular used in gearboxes for motor vehicles. In the state of the art, there are also already gearboxes with synchronization, called servo synchronization to facilitate the synchronization operation. The rotational torque energy of the rotating gears relative to each other is then used to enhance the gear shift force applied to the synchronizing unit by means of the shift lever of the gearshift linkage. Document DE 10 2010 004 382 A1 thus discloses a generic synchronization unit, in which bearing surfaces are made on axial extensions of the synchronization ring, which are capable of cooperating with corresponding opposing surfaces on the body of the synchronization ring. synchronization and / or on the synchronizing slider of the locking wedge synchronization assembly, the bearing surfaces being inclined at least -2 in sections so that a force acting on the bearing surfaces in the direction device urges the synchronization ring with an axial force component against the speed gear to be coupled. In the embodiment having inclined bearing surfaces on the synchronization ring and corresponding counter surfaces on the synchronization body, the strengthening of the shift force is however limited, since only a differential torque between the synchronizing torque and the unlocking torque causes an increase in the pressure force on the synchronization ring. In this context, we also speak of a "partial" servo synchronization. In the embodiment having inclined bearing surfaces on the synchronization ring and corresponding counter surfaces on the synchronizing slide of the locking wedge synchronization unit, the synchronous torque is fully supported on the surfaces of the synchronization ring. oblique support of the synchronization ring, which is also called "complete" servo synchronization. Due to the inclined antagonistic surfaces on the timing slider, unwanted feedback, however, occurs on the sliding sleeve, so that the axial force component for the reinforcement of the shifting force in a manual gearbox must be applied by the driver for example in the form of a higher gear shift force. The object of the invention is to provide a synchronization unit for gearboxes, in which a component of reinforcing axial force is generated from the total synchronization torque during a gearshift, without feedback on the force. gearshift that must be applied. According to the invention, this object is achieved by a synchronization unit of the type mentioned in the introduction, in which bearing surfaces which are able to engage on corresponding counter surfaces of the synchronization body are formed on the blocking slide the bearing surfaces and / or antagonists being inclined at least in portions so that a force acting in the circumferential direction between the locking slide and the synchronizing body causes an axial force component which forces the synchronization ring against the speed gear to be coupled or against a clutch disk integrally connected to the gear wheel. The synchronization torque can thus be fully used for the reinforcement of the applied gear shift force. The counterforce to the reinforcing effect axial force component 5 is then introduced into the gearbox shaft via the synchronizing body, so that the shifting force to be applied is not influenced. . In one embodiment of the synchronization unit, the blocking slide has opposed peripheral ends which are each provided with at least one bearing surface, two opposing bearing surfaces in the peripheral direction extending in oblique towards each other in the axial direction. This slight adjustment of the peripheral ends of the locking slide provides a particularly simple possibility at the constructive level for achieving the desired reinforcement of the gear change force.

Two bearing surfaces are preferably provided on each peripheral end, two opposed bearing surfaces in the circumferential direction extending obliquely towards each other in the axial direction, so that the peripheral ends are seen in the radial direction, have a wedge shape. The bearing surfaces may then either terminate at a point towards the peripheral end and be directly contiguous, or terminate in a truncated manner and be contiguous only indirectly by a connecting surface, the connecting surface extending substantially parallel to a radial plane. Since two bearing surfaces inclined relative to each other and to a radial plane are respectively provided on both peripheral ends, an assistance of the shifting force in both axial directions to from a central neutral position is ensured. The bearing surfaces preferably each extend parallel to a plane which from a radial plane is tilted at an angle to an axis of rotation arranged in the radial plane and extending substantially radially. These planar shaped bearing surfaces are of simpler construction relative to curved bearing surfaces, and further contribute to an axially simple-to-determined axial force component which has a reinforcing effect, and which is dependent on the force acting in the peripheral direction between the locking slide and the synchronizing body. The opposing surfaces are preferably made on corner-like extensions of the sync body protruding in the peripheral direction. In this case, for example, the synchronization body has a recess which, seen in the peripheral direction, has opposite end faces, the extensions extending from the end faces towards the recess. The opposing surfaces extend particularly preferably substantially parallel to the respectively associated bearing surfaces. The bearing surfaces and the opposing surfaces thus form large areas of contact during a transmission of force. This contributes to reduced surface pressure and thus reduced wear at the locking slide and the synchronizing body, whereby the service life of the synchronizing unit is prolonged. In one embodiment of the synchronization unit, the synchronization ring is made without locking toothing, and only the locking slide can allow or block axial movement of the sliding sleeve with respect to the synchronizing slide. Such a locking mechanism offers considerable manufacturing advantages, since the manufacturing costs for the synchronization ring are considerably reduced. It is of course preferably provided several lock corner synchronization assemblies distributed over the periphery of the synchronization body. The locking wedge timing unit preferably also has a spring member which biases the locking slider radially outwardly relative to the transmission shaft and against the slidable sleeve. A groove section which extends in the circumferential direction and which can engage the blocking slide is particularly preferably made in the sliding sleeve. This groove portion allows in the peripheral direction a guided relative movement of the locking slide relative to the sliding sleeve. The friction or synchronization torque active on the synchronization ring is therefore transmitted only by the bearing surfaces on the locking slide or the opposing surfaces on the synchronization body. Unlike the so-called partial servo synchronization, the active unlocking torque between the blocking slide and the synchronizing slide does not cause a reduction in the axial force component 5 with a reinforcing effect. A rotation of the synchronization rings in their blocking position (referred to as indexing) is in this case carried out only by means of the blocking slide. This means that the synchronizing slider as well as the timing rings, as compared to the locking wedge synchronization according to DE 10 2007 010 307 B3, do not have a predetermined torsion angle or fixed stop in the body. synchronization. In one embodiment of the synchronization unit, the synchronizing body has a recess in which the locking wedge synchronization assembly is received, the synchronization slider being received in the recess so as to be movable in the recess. peripheral sense, especially in a limited way. Such a recess is already provided with one or more locking wedge synchronization assemblies in the conventional synchronization units, and should only be slightly adapted to the constructive level with respect to its cross-section to allow a desired cooperation between the slider. blocking and the synchronizing body via the bearing or antagonistic surfaces. In this embodiment, the synchronizing ring preferably has axial extensions which extend into the recess, the synchronizing slider preferably being arranged substantially without play in the circumferential direction between two axial extensions of the synchronization ring. . On this point, it is thus possible to keep the construction of conventional synchronization units having a lock corner synchronization assembly. Other features and advantages of the invention result from the following description of a preferred embodiment with the aid of the drawings. These show: FIG. 1 a detail in longitudinal section of a gearbox having a synchronization unit according to the invention, in the zone of a locking wedge synchronization assembly; FIG. 2 is a cross-sectional detail of the gearbox according to FIG. 1 in the region of the locking wedge timing assembly; - Figure 3 a top view in perspective on the gearbox according to Figures 1 and 2 (without sliding sleeve) in the region of the locking wedge synchronization assembly; FIG. 4 is a perspective detail view of the locking wedge timing assembly of FIG. 3; - Figure 5 a cross-sectional X-X sectional detail of the synchronization unit according to the invention of Figure 2 in a central neutral position; FIG. 6 is a cross-sectional detail X-X of the synchronization unit according to the invention of FIG. 2 in a synchronization position; - Figure 7 an exploded perspective view of a gearbox having an alternative embodiment of the synchronization unit according to the invention, in the area of a locking wedge synchronization assembly; Figure 8 is an exploded perspective view of the locking wedge timing assembly of Figure 7; - Figure 9 a cross section through the gearbox according to claim 7; FIG. 10 is a longitudinal section through the gearbox according to FIG. 7 in the region of the locking wedge synchronization assembly; Fig. 11 is a cross-sectional detail of the gearbox according to Fig. 7 in the region of the locking wedge timing assembly; FIG. 12 is a perspective view from above of the synchronization unit according to FIG. 7 (without sliding sleeve) in the region of the locking wedge synchronization assembly; and FIG. 13 is a cross sectional detail XIII-XIII of the gearbox according to FIG. 9 in a central neutral position. Figures 1 and 2 show a longitudinal sectional detail and a cross-sectional detail, respectively, of a gearbox 10, more precisely a synchronization unit 12 of the gearbox 10. The synchronization unit 12 comprises a synchronizing body 14 which is arranged to rotate with a gearbox shaft and which rotates about an axis of rotation A in the peripheral direction 16, a sliding sleeve 18 which is integrally connected in rotation with the synchronization body 14 and which is arranged in an axially displaceable manner with respect to the synchronization body 14, on each axial side of the synchronization body 14 a synchronization ring 22 for the coupling of the synchronization body 14 to a corresponding speed gear of the gearbox 10 by a friction connection, as well as a synchronization assembly 26 with locking wedge which engages the sliding sleeve 18 and which solicits the synchronizing ring 22 with an axial shift force F (FIG. 6) against the gear gear to be coupled during an axial displacement of the sliding sleeve 18. FIG. 1 does not show the gear wheel of the gearbox 10, but only a clutch disk 24 which is adjacent to the gear pinion and which is fixedly connected, in particular rotationally fixed to the gear pinion. In alternative embodiments, the clutch disk 24 and the gear wheel can also be made in one piece. The locking wedge timing assembly 26 has a timing slider 28, a locking slider 30 which is received in an orifice in the timing slider 28 in a substantially non-displaceable manner in the axial direction 20, but displaceable in the radial direction 32 and in the peripheral direction 16, and a spring element 34 which urges the locking slide 30 radially outwardly relative to the axis A of the gearbox and against the sliding sleeve 18. Several sets The synchronizing unit 12 has a locking mechanism 26 with locking wedges on the periphery of the synchronization body 14. Because of these locking wedge synchronization assemblies 26, the synchronizing unit 12 has a particular locking mechanism in which the blocking slide 30 is able to allow or block an axial movement of the sliding sleeve 18 with respect to the synchronization slide 28. In FIG. In this case, the synchronizing ring 22 can therefore be made in the form of a simple conical ring and without locking toothing. In comparison with synchronizing rings having a locking toothing, the mounting costs for synchronizing rings 22 made without locking toothing are considerably reduced.

The general operating principle of gearboxes 10 having such a locking wedge synchronization assembly 26 is already described in detail in DE 10 2007 010 307 B3, which is expressly referred to in this respect, and will be explained. in what follows only in outline with the help of a passage of speed.

From an unengaged neutral position of the gearbox 10 according to FIGS. 1 and 2 (see also FIG. 5), an axial shift force F (FIG. 6) is applied to the sliding sleeve 18 by This is done by means of a gearbox fork (not shown), so that the sliding sleeve 18 is biased towards gear clutch gear teeth. The spring 34 is placed under the locking slide 30 in a recess of the synchronizing slide 28 and pushes the locking slide 30 radially outwardly. For this purpose, the spring element 34 bears either on the synchronization body 14 (see FIGS. 1 and 2) or alternatively on the synchronization slide 28. The locking slide 30 engages in the axial direction 20 in a groove portion 36 of the sliding sleeve 18 in substantially shaped engagement (see FIG. 1), and is biased axially against the synchronizing slide 28 upon the application of the shifting force F, the slide the synchronizing ring being axially biased against the synchronizing ring 22, and the synchronizing ring 22 being in turn biased against a friction surface of the gear wheel by means of a friction surface made conically. During a difference in rotational speeds between the synchronization body 14 and the speed gear, a relative movement between the synchronization ring 22 and the synchronization body 14 is achieved because of the frictional connection. between the synchronization ring 22 and the gear wheel.

Since the synchronizing slider 28 is usually retained without clearance in the circumferential direction 16 between two axially spaced axial extensions 16 (see Fig. 2) of the synchronizing ring 22, and the locking slide 30 is coupled to the synchronizing body 14 with little clearance in the peripheral direction 16 (see FIGS. 5 and 6), resulting in a relative movement between the synchronizing slide 28 and the locking slide 30. This relative movement is limited by co-operating corner surfaces 38 (see FIG. 2) on the synchronizing slide 28 and the locking slide 30, these corner surfaces 38 urged against each other to prevent movement of the slide first. blocking device 30 radially inwardly, and thus axial movement of the sliding sleeve 18 in the direction of the gearing gearing 35. The radially inward force component is generated by an oblique axial surface 40 on the locking slide 30 and a corresponding oblique antagonistic surface 42 on the slide sleeve 18.

The shift force F is sufficient to move the locking slider radially inwardly and to slide the slidable sleeve 18 axially onto the gearshift teeth 35 of the clutch disc 24 by extending it past the slider. 30 only when the application pressure between the corner surfaces 38 decreases due to a synchronization of the rotational speeds between the synchronization body 14 and the gear wheel. The synchronization body 14 and the speed gear are then connected by shape cooperation and substantially without play in the peripheral direction 16 via the sliding sleeve 18 and the clutch disc 24.

In the zone of its outer periphery, the synchronizing body 14 has a recess 44 in which the synchronization assembly 26 with locking wedge is received. Several, in particular, three locking wedge synchronization assemblies 26 are usually provided, which are regularly distributed over the periphery of the synchronization body 14. Correspondingly, there are also several arrangements, in particular three recesses 44 for receiving a synchronization assembly 26 with respective locking wedges in the synchronization body 14.

According to Figure 2, the depression 44 is substantially composed of a peripheral slot 48 and a radial slot 50, which intersects the peripheral slot 48 approximately in the center. In the radial slot 50 are the radially displaceable locking slider 30 and the spring element 34 which is here formed as a helical compression spring and which urges the locking slider 30 radially outwards against the sliding sleeve 18 The synchronizing slider 28 of the locking wedge synchronization assembly 26 is received in the peripheral slot 48 of the recess 44 so as to be limitedly displaceable in the peripheral direction 16. The synchronization assembly 26 with a wedge blocking is held integral in rotation with respect to a radial axis of the synchronization assembly 26 with locking wedge. This rotationally fixed assembly is produced according to the embodiment, for example by the coupling secured in rotation between the sliding sleeve 18 and the locking slide 30, as well as by the housing of the latter in the synchronization slide 28 to be movable 20 only in the peripheral direction 16, and / or by the fixed fastening in rotation of the synchronizing slide 28 between two axial extensions 37 of the synchronization ring 22. The axial extensions 37 of the synchronization ring 22 s extend in the recess 44, concretely in the peripheral slot 48 of the recess 44, the synchronizing slider 28 being arranged substantially without play in the circumferential direction 16 between two axial extensions 37 of the synchronization ring 22. synchronizing slide 28, together with the synchronizing ring 22, is rotated in a limited way in the peripheral direction 16 by rap. port to the synchronization body 14.

Opposing peripheral ends 52, 53 of the locking slide 30 are directly adjacent to opposite peripheral ends 54, 55 of the synchronization body 14 due to the shape of the cross-section of the depression 44. In the view of FIG. perspective view according to Figure 3, it becomes clear that bearing surfaces 56a, 56b, 58a, 58b are formed on the locking slide 30, which are adapted to engage on opposing surfaces 60a, 60b, 62a, Corresponding 62b of the synchronization body 14.

The abutment and abutment surfaces 56a, 56b, 58a, 58b, 60a, 60b, 62a, 62b are then inclined such that a friction (FR) force acting in the peripheral direction 16 between the locking slide 30 and the synchronizing body 14 biases the synchronizing ring 22 with an axial force component Fservo against the gear gear to be coupled or against the clutch disc 24 integrally connected to the gear wheel (see FIG. 6) . Figure 4 shows the lock corner timing assembly 26 in a perspective detail view. It is clearly visible here that two bearing surfaces 56a, 56b and 58a, 58b are formed on each peripheral end 52, 53 of the locking slide 30, two bearing surfaces 56a, 58a or 56b, 58b opposite one another in the opposite direction. device 16 extending respectively obliquely to each other in the axial direction 20, so that the peripheral ends 52, 53, seen in the radial direction 32, have a wedge shape. In this case, a reinforcement of the shifting force is generated independently of the displacement of the sliding sleeve 18 from its central neutral position in a first axial direction or in a second opposite axial direction. Embodiments are of course also conceivable, in which the locking slide 30 has opposed peripheral ends 52, 53, which are each provided with a single bearing surface 56a, 58a or 56b, 58b, the two surfaces the circumferentially opposed bearing 56a, 58a or 56b, 58b extending obliquely towards each other in the axial direction 20. The strengthening of the shifting force is then carried out only in one two axial directions of gear change. FIG. 5 shows a tangential sectional detail X-X of the synchronization unit 12 according to FIG. 3 in a central neutral position. It becomes clear that the bearing surfaces 56a, 56b, 58a, 58b each extend parallel to a plane E which is tilted from a radial plane ERadial at an angle α relative to an axis of rotation Arot which lies in the ERadial radial plane and extends substantially radially. The blocking slide 30 has concretely opposed peripheral ends 52, 53 which are each provided with two bearing surfaces 56a, 56b or 58a, 58b inclined with respect to each other and with respect to the plane. radial ERadial.

According to Figure 5, the two bearing surfaces 56a, 56b or 58a, 58b of a peripheral end 52, 53 inclined relative to the radial plane ERadial are directly adjacent so that the peripheral ends 52, 53 wedge-shaped each ends in a point. Alternatively, a connecting surface 64 which extends substantially parallel to the radial plane ERadial can be made between the inclined bearing surfaces 56a, 56b or 58a, 58b, respectively, of a peripheral end 52, 53. Such a Embodiment is shown in dashed lines in FIG. 5. According to FIG. 5, two opposing surfaces 60a, 60b or 62a, 62b are also provided on each peripheral end 54, 55 of the synchronization body 14 so as to be adjacent to the hollow 44, two opposing surfaces 60a, 60b or 62a, 62b opposite in the peripheral direction 16 extending respectively obliquely towards each other in the axial direction 20, so that the peripheral ends 54, 55, seen in the radial direction 32, have a wedge shape.

The opposing surfaces 60a, 60b, 62a, 62b are here formed on corner-like extensions 66, 67 of the synchronization body 14 which protrude into the recess 44 in the peripheral direction 16. The synchronization body 14 thus has the adjacent the hollow 44 of the opposing peripheral ends 54, 55 which are each provided with two opposing surfaces 60a, 60b or 62a, 62b, respectively, which are inclined with respect to each other and with respect to the radial plane ERadial. By analogy with the bearing surfaces 56a, 56b or 58a, 58b, the two opposing surfaces 60a, 60b or 62a, 62b of a peripheral end 54, 55 which are inclined relative to the radial plane ERadial can be directly adjacent to each other. so that the wedge-shaped peripheral end 54, 55 terminates in a point. Alternatively, a bonding surface 68 which extends substantially parallel to the radial plane ERadial can be made between the opposing surfaces 60a, 60b or 62a, 62b. On this point, it is again referred to FIG. 5. The advantage of an alternative embodiment with connecting surfaces 64, 68 is that in the appearance of drive couples in the central neutral position of FIG. the synchronization unit 12, no axial force component Fservo reinforcement is generated. Indeed, in this case, the force component Fservo would not enhance the shift force F but unwanted drive torques. FIG. 6 shows the tangential sectional detail of the synchronization unit 12 according to FIG. 5, the synchronization unit 12 being no longer in its central neutral position, but in an axially-out synchronization position. In this synchronizing position, the shifting force F applied to the blocking slide 30 via the sliding sleeve 18 causes axial movement of the locking slide 30, the synchronizing slide 28 and the locking ring 30. synchronization 22 until the synchronizing ring 22 is in frictional engagement with the gear wheel. Due to the difference in the rotational speeds between the synchronization ring 22 and the synchronization body 14, the blocking slide 20 is urged by the synchronizing slide 28 connected in rotation with the synchronization ring 22 in a peripheral direction 16 against the synchronization body 14 with the friction force or synchronization FR. In the present case, the bearing surface 58a and the associated opposing surface 62b come into correspondingly contact, the locking slide 30 and thus the synchronizing ring 22 being biased by an axial force component Fservo which acts in the same direction as the force of change of speed F. The force opposing the force component Fservo is introduced into the synchronization body 14 and is evacuated by its thrust bearing. Therefore, there is no feedback on the sliding sleeve 18 or the shift force F to be applied. The blocking slide 30 engages in the groove section 36 which extends in the circumferential direction 16 (see FIGS. 1 and 2). The groove portion 36 thus forms a guide in the peripheral direction 16 for the locking slide 30 and allows corresponding relative movement between the locking slide 30 and the sliding sleeve 18. A friction or synchronization torque MR active at the synchronizing ring 22 is therefore transmitted only by bearing surfaces 56a, 56b, 58a, 58b of the blocking slide 30 or the opposing surfaces 60a, 60b, 62a, 62b on the synchronization body 14. Unlike a so-called partial servo synchronization, an active release torque between the blocking slide 30 and the synchronizing slide 28 does not cause a reduction in the axial force component Fsen, o with reinforcing effect. A rotation of the synchronizing rings 22 in their locking position (called indexing) is in this case only carried out by means of the locking slide 30. To minimize the surface pressures of the bearing surfaces 56a, 56b, 58a, 58b and counter-surfaces 60a, 60b, 62a, 62b cooperating in the timing position, the opposing surfaces 60a, 60b, 62a, 62b extend substantially parallel to their associated bearing surfaces 56a, 56b, 58a, 58b. Figures 7 to 13 show the gearbox 10 with the synchronization unit 12 according to an alternative embodiment. Since this embodiment of the synchronization unit 12 corresponds substantially to the embodiment according to FIGS. 1 to 6 as regards their fundamental construction and the general operation, we refer explicitly to this point to the above description. above the figures. Only differences between the two embodiments will be explained in the following.

FIG. 7 shows an exploded perspective view of the gearbox 10. The synchronization body 14, by analogy with the first embodiment of the synchronization unit 12 according to FIGS. 1 to 6, is arranged axially between two synchronization rings 22. To couple the synchronizing slides 28 to the synchronous ring 22 substantially without play in the peripheral direction 16, the synchronizing rings 22 have instead of the axial extensions 37 according to FIG. which extend the engagement sections 72 of the synchronizing sliders 28 which extend so as to be bent radially inwardly. The engagement by cooperation of shapes of the synchronizing sliders 28 in the recesses 70 is then carried out with such precision of adjustment that the synchronizing sliders 28 are connected substantially rotationally fixed to the synchronization ring 22 (FIG. see also Figure 12).

As is clearly visible in the cross-section of the gearbox according to FIG. 9, this constructive modification of the synchronization unit 12 has an advantageous effect in particular on the manufacture of the synchronization body 14, since it It is possible to manufacture the depressions 44 inexpensively in the synchronization body 14. Compared with the recess 44 of FIG. 2, it is possible to do without complicated undercuts for the extensions 37 of the locking ring. synchronization and thin-walled bars for producing the opposing surfaces 60a, 60b, 62a, 62b. In the longitudinal section of the gearbox of FIG. 10, it clearly appears that the synchronization slider 28 according to the second embodiment of the synchronization unit 12 bears on the synchronization ring 22 in the radial direction 32. On the other hand, the synchronizing slider 28 in the first embodiment is radially supported on the synchronization body 14, so that in particular during a disengagement of a past speed (unlocking operation), a force Unwanted friction between the synchronizing body 14 and the synchronizing slider 28 is produced which could slightly impair the comfort of shifting. The synchronizing body 14 of FIG. 10 is furthermore arranged axially between the two synchronizing rings 22, the synchronizing slider 28 coupling the two synchronizing rings 22 substantially without play in the axial direction 20. Due to the axial coupling of In synchronization rings 22, the friction losses due to unwanted drive torques are minimized in the neutral position of the gearbox 10. This is also referred to as "forced ventilation" of the timing rings 22. In comparison with the first embodiment, the axial dimensions of the synchronizing sliders 28 in the second embodiment of the synchronization unit 12 are considerably higher. Due to the radial support of each synchronizing slide 28 on the synchronization ring 22 through the entire axial dimension of the ring in the area of the recesses 70, and because of the With support for the sliding sleeve 18 (see FIG. 10), the overturning torques and the clamping forces acting on the individual timing slides 28 during a shift are considerably reduced. This again has an advantageous effect on the comfort of shifting. FIG. 8 shows a detailed view of the locking wedge synchronization assembly 26 for the second embodiment of the synchronization unit 12. As in the first embodiment according to FIGS. 1 to 6, FIG. synchronization assembly 26 with locking wedge comprises the synchronizing slide 28, the locking slide 30 which is substantially non-displaceable in the axial direction 20 with respect to the synchronizing slide 28, but which is arranged radially movable 32 and in the peripheral direction 16, as well as the spring element 34 which urges the locking slide 30 radially outwards with respect to the axis A of the gearbox and against the sliding sleeve 18. With regard to the general function principle of the gearbox 10 and the locking mechanism of the synchronization unit 12, there is no change, so that it is referred to the corresponding explanations of the first 1st embodiment. From a constructive point of view, the synchronization assembly 26 with locking wedge is however considerably modified. The synchronizing slide 28 has, for example, in the longitudinal section a central bar 74 in which the spring element 34 is received. To the bar 74 is joined on both axial sides a respective support section 76 for bearing against the synchronizing rings 22, the support sections 76 respectively melting in an engagement section 72 at the axial ends of the slider. synchronization 28, the engagement section engaging one of the recesses 70 of the synchronization ring. According to FIG. 10, the synchronizing slider 28 engages around the two synchronization rings 22 by being directly adjacent to a radial outer face and to the two axial end faces of each synchronization ring 22. 2975455 -17- Several locking cams 78 which protrude radially outwards and which have corner surfaces 38 are formed on the side of the bearing section 76 which is diverted from the synchronization ring 22. Complementary locking cams 80 which also have corner 38 are made on the blocking slide 30 (see FIGS. 11 and 13). During a shift, the corner surfaces 38 of the locking cams 78, 80 cooperate in the same manner as described above for the first embodiment of the timing unit 12. Instead of a pairing In the first embodiment of FIG. 2, in the second embodiment, in the second embodiment, in a synchronization slider 28 with four locking cams 78 according to FIG. corner surfaces by synchronization direction. The blocking slide 30 can thus be better oriented at the corner surfaces 38 when the synchronizing unit 12 is in the blocking position, whereby undesired tilting of the blocking slide 30 is prevented. Due to the greater number of corner surfaces 38, the effective total bearing area is further increased and thus the maximum generated surface pressure reduced.

Figure 11 shows a detail of the timing unit 12 according to the second embodiment. Opposing peripheral ends 52, 53 of the locking slide 30 are here directly adjacent to the opposite peripheral ends 54, 55 of the synchronization body 14. In the perspective top view according to FIG. 56a, 56b, 58a, 58b adapted to engage on corresponding opposing surfaces 60a, 60b, 62a, 62b of the synchronization body 14 are formed on the blocking slide 30. By analogy with Figure 5 for the first embodiment of the synchronization unit 12, FIG. 13 for the second embodiment of the synchronization unit 12 shows a tangential sectional detail of the gearbox 10 according to FIG. 9. In the second embodiment In this embodiment, the abutment and abutment surfaces 56a, 56b, 58a, 58b, 60a, 60b, 62a, 62b are generally also inclined such that the friction force FR acts in the peripheral direction. 16 between the blocking slide 30 and the synchronizing body 14 biases the synchronizing ring 22 with the axial force component Fsen, or against the speed gear to be coupled or against the clutch disc 24 connected in solidarity with one another. speed gear (see Figure 6). The principle, how the axial force component Fservo is generated from the force FR acting in the peripheral direction 16 between the blocking slide 30 and the synchronizing body 14 is entirely identical for the first and the second embodiment of FIG. synchronization unit 12. On this point, it is therefore explicitly referred to Figures 5 and 6 and the corresponding description.

Claims (14)

REVENDICATIONS1. A synchronization unit of a gearbox (10), comprising a synchronization body (14) rotatably mounted on a transmission shaft, a sliding sleeve (18) arranged to rotate with respect to the synchronization body ( 14), but axially displaceable, a synchronization ring (22) for coupling the synchronization body (14) to a gear wheel gearbox (10) by a friction connection, and a synchronization assembly (26). ) with locking wedge which engages on the sliding sleeve (18) and which biases the synchronizing ring (22) with an axial shift force (F) against the gear gear to be coupled during a displacement axial direction of the sliding sleeve (18), the locking wedge synchronization assembly (26) having a synchronizing slide (28) and a locking slide (30), characterized in that bearing surfaces (56a, 56b 58a, 58b) which are able to engage corresponding counter-surfaces (60a, 60b, 62a, 62b) of the synchronization body (14) are formed on the locking slide (30), the bearing surfaces and / or the opposing surfaces (56a, 56b, 58a, 58b, 60a, 60b, 62a, 62b) being inclined at least in portions such that a force (FR) acting in the circumferential direction (16) between the locking slide (30) and the synchronization body (14) causes a axial force component (Fservo) which urges the synchronization ring (22) against the speed gear to be coupled. Synchronization unit according to Claim 1, characterized in that the locking slide (30) has opposite peripheral ends (54, 55) which are each provided with at least one bearing surface (56a, 56b, 58a). 58b), two opposing peripheral bearing surfaces (56a, 58a; 56b, 58b) extending obliquely towards each other in the axial direction (20). 2975455 - 20 - 3. synchronization unit according to claim 2, characterized in that two bearing surfaces (56a, 56b; 58a, 58b) are formed on each peripheral end (54, 55), two bearing surfaces (56a, 58a; 56b, 58b) in the peripheral direction (16) extending obliquely towards each other in the axial direction (20), so that the peripheral ends (54, 55), seen in the radial (32), have a wedge shape. 4. synchronization unit according to one of the preceding claims, characterized in that the bearing surfaces (56a, 56b; 58a, 58b) extend respectively parallel to a plane (E) which, from a plane radial (ERadial), 10 is tilted at an angle (a) relative to an axis of rotation (Arot) arranged in the radial plane (ERadial) and extending substantially radially. Synchronization unit according to one of the preceding claims, characterized in that the opposing surfaces (60a, 60b, 62a, 62b) are formed on wedge-shaped extensions (66, 67) of the synchronizing body (14). ) which protrude in the peripheral direction (16). 6. Synchronization unit according to one of the preceding claims, characterized in that the opposing surfaces (60a, 60b, 62a, 62b) extend substantially parallel to the bearing surfaces (56a, 56b; 58a, 58b) respectively associated . 20 Synchronization unit according to one of the preceding claims, characterized in that the synchronizing ring (22) is formed without locking toothing, and in that the locking slide (30) can allow or block an axial movement. sliding sleeve (18) with respect to the synchronizing slide (28). 25 8. Synchronization unit according to one of the preceding claims, characterized in that the locking wedge synchronization unit (26) has a spring element (34) which urges the locking slide (30) radially outwards. relative to the gearbox shaft and against the sliding sleeve (18). 30 9. Synchronization unit according to one of the preceding claims, characterized in that a groove section (36) extending in the peripheral direction (16) and in which the locking slide (30) can engage is realized in the sliding sleeve (18). Synchronization unit according to one of the preceding claims, characterized in that the synchronizing body (14) has a recess (44) in which the locking wedge synchronization assembly (26) is received. the blocking slider (28) being received in the recess (44) so as to be displaceable in the peripheral direction (16), in particular in a limited manner. 11. Synchronization unit according to claim 10, characterized in that the synchronization ring (22) has axial extensions (37) which extend in the recess (44), the synchronizing slide (28) being arranged substantially without clearance in the peripheral direction (16) between two axial extensions (37) of the synchronization ring (22). 12. Synchronization unit according to one of the preceding claims, characterized in that the synchronizing slide (28) bears against the synchronization ring (22) in the radial direction (32). Synchronization unit according to one of the preceding claims, characterized in that the synchronizing slide (28) extends in a recess (70) of the synchronization ring (22) in such a way that the synchronizing slide (28) is coupled to the synchronizing ring (22) substantially without play in the circumferential direction (16). Synchronization unit according to one of the preceding claims, characterized in that the synchronization body (14) is arranged axially between two synchronization rings (22), the synchronization slide (28) coupling the two synchronization rings ( 22) substantially free of play in the axial direction (20).