CN110725868A - Synchronization unit for a transmission - Google Patents

Abstract

The invention relates to a synchronization unit (10) for a transmission, comprising a gear wheel (12), a synchronizer ring (16) and a friction ring (14), the friction ring (14) being frictionally engageable with the synchronizer ring (16) and being directly engageable with the gear wheel (12) by means of an engagement geometry (34) comprising at least one recess (38) and at least one protuberance (36) in such a way that the protuberance (36) engages into the recess (38) and mechanically couples the friction ring (14) and the gear wheel (12) in the direction of rotation, the at least one protuberance (36) being provided on the friction ring (14) or the gear wheel (12) and the at least one recess (38) being provided on the respective other of the friction ring (14) and the gear wheel (12), and the friction ring (14) having a radially inner surface (20) and a radially outer surface (18), the faces each diverge at a cone angle, the cone angle of the inner surface (20) being different from the cone angle of the outer surface (18).

Description

Synchronization unit for a transmission

Technical Field

The invention relates to a synchronization unit for a transmission.

Background

During a gear change in the transmission, a synchronizing body, which is mounted in a rotationally fixed manner on a shaft, is connected via a sliding sleeve to a gear wheel, which is arranged as a loose wheel on the shaft. In order to synchronize the shifting process, the synchronization unit is configured according to the prevailing burger warner principle: a synchronizer ring with a locking toothing is provided, which is fixed to the synchronizer body in a manner that it can move in a limited manner in the circumferential direction. When an axial shifting force is applied to the synchronizer ring via the sliding sleeve, this synchronizer ring is pressed against a friction surface coupled with the gear wheel in order to equalize the rotational speeds of the synchronizer body and the gear wheel. The synchronizing ring is rotated relative to the synchronizing body during synchronization by means of friction forces acting in the circumferential direction, so that the toothing of the synchronizing ring initially prevents further axial movement of the sliding sleeve. With synchronous operation, the synchronizer ring can be reset in the circumferential direction and the sliding sleeve can be brought into engagement with the toothing of the gear wheel.

A compromise is often reached in the design of the synchronization unit in terms of efficiency and shift comfort.

Disclosure of Invention

The object of the invention is therefore: a synchronization unit is provided which is optimized with regard to efficiency and shift comfort.

According to the invention, the object is achieved by a synchronization unit for a gear, comprising a gear wheel, a synchronization ring and a friction ring, wherein the friction ring can be brought into frictional engagement with the synchronization ring and can be brought into direct engagement with the gear wheel by means of an engagement geometry comprising at least one recess and at least one protuberance, in that the protuberance engages into the recess and mechanically couples the friction ring and the gear wheel in the direction of rotation. The at least one elevation is provided here on the friction ring or on the catch wheel, and the at least one recess is provided on the respective other element of the friction ring and the catch wheel. The friction ring has a radially inner and a radially outer inner surface, which each diverge at a cone angle, wherein the cone angle of the inner surface differs from the cone angle of the outer surface.

Instead of a one-piece friction ring, a plurality of ring segments or only one ring segment can also be provided. This can have advantages when assembling the friction ring.

The friction ring is always reliably coupled to the gear wheel by the engagement geometry during synchronization in a simple manner.

However, the engagement geometry may allow a certain relative movement between the friction ring and the gear wheel in the rotational direction and/or in the axial direction. By this relative movement, the disengagement of the synchronizer ring from the frictional engagement after the shifting process is simplified. This will be explained in more detail below.

It is also possible to: there are a plurality of gaps and elevations on the friction ring or the catch wheel. Both the elevations and the recesses can be provided on the friction ring and on the catch wheel, respectively. The friction ring is supported in a rotationally fixed manner on the catch wheel by the presence of a plurality of elevations or recesses on the catch wheel.

The taper angle on the friction ring can advantageously affect the quality of the driver's shift feel during a shift. The taper angle at the same time has an influence on the release behavior of the friction element at the end of the synchronization, in particular on the release of the friction ring from the synchronizer ring. The synchronization unit can be optimized with regard to the achievable friction torque and the disengagement behavior by means of different cone angles.

The friction ring can be made of powder metal by, for example, mechanically compacting a metal powder and sintering it at high temperature to form a compact. Here, complex geometries can also be realized in the friction ring. Alternatively, the friction ring may be a shaped piece, for example a sheet piece. Such components can generally be manufactured economically. Furthermore, the friction ring can be produced by a machining method or can be a cast or forged part.

According to a preferred embodiment, the taper angle of the outer surface of the friction ring is smaller than the taper angle of the inner surface of the friction ring. Since the taper angle of the outer surface of the friction ring is smaller than the taper angle of the inner surface, a particularly high friction torque can be generated between the synchronizer ring and the friction ring. In particular, the friction between the synchronizer ring and the friction ring is in the self-locking range. A particularly short synchronization time and thus an improvement in the shift quality can be achieved on account of the high friction torque by means of a small cone angle on the outer surface of the friction ring. At the same time, improved shift quality can be achieved in that the cone angle of the inner surface is greater than the cone angle of the outer surface. The large taper angle of the inner surface of the friction ring facilitates disengagement from the frictional engagement. In particular, the friction between the friction ring and the gear wheel is outside the self-locking. In this way, the coupling between the gear wheel and the synchronizer ring, which is determined by the frictional engagement, can be disengaged in a simple manner after a shifting operation. In particular, the shift quality is not adversely affected by clamping and/or tensioning after the synchronization process, so that the shift comfort is thereby increased.

For example, the taper angle of the outer surface of the friction ring is between 1 ° and 6 °. In this angular range, a self-locking between the synchronizing ring and the friction ring can be performed during synchronization. In this way, good shifting performance is achieved.

Preferably, the taper angle of the outer surface of the friction ring differs, in particular by more than 1 °, from the taper angle of the inner surface of the synchronizing ring. And therefore there is an angular difference. This enables good separation properties (Losbrechverhalten) to be achieved.

According to an alternative embodiment, the taper angle of the outer surface of the friction ring can substantially coincide with the taper angle of the inner angle of the synchronizing ring, wherein no deviations occur due to manufacturing tolerances.

The taper angle of the inner surface of the friction ring is, for example, between 5 ° and 15 °, particularly preferably between 7 ° and 12 °. In this angular range no self-locking occurs on the inner surface of the friction ring.

In order to limit the mobility of the friction ring in the axial direction relative to the gear wheel or to fix the friction ring firmly in the axial direction on the gear wheel, an axial stop can be provided. This axial stop can be realized, for example, by the taper angle of the inner surface of the friction ring, in particular if a corresponding taper surface is provided on the catch wheel, on which taper surface the friction ring can bear. Alternatively or additionally, the axial stop can be realized in other ways, for example by the at least one projection being able to stop or be fixable on the catch wheel.

According to a preferred embodiment, the friction ring is located radially inside the synchronizing ring. The synchronizer ring can thus be pressed against the friction ring during a gear shift in order to establish a frictional engagement between the synchronizer ring and the friction ring. Since the friction ring is in turn mechanically coupled with the gear wheel, an indirect frictional engagement is also established between the synchronizer ring and the gear wheel via the friction ring.

However, it is also conceivable: in an alternative embodiment, the friction ring is arranged around the synchronizing ring, in particular radially outside the synchronizing ring. In this case, the synchronizer ring can have an elevated functional surface on the conical surface, which, in operation, contracts the friction ring and thereby establishes frictional contact between the friction ring and the synchronizer ring.

The friction ring may have an interruption in the circumferential direction, which is formed by an axially and radially continuous groove in the friction ring. The friction ring is elastic by the interruption. In particular, the friction ring has a low radial stiffness due to the interruptions. This is advantageous in terms of the coupling properties of the friction ring (Kopplungsverhalten). In particular, the interruptions in the friction ring contribute to the release properties of the friction surface.

After the synchronization process or during the unlocking process when the synchronizer ring is moved away from the gear wheel, the friction ring can be elastically relaxed due to the axial force acting on the synchronizer ring being stopped. This eliminates the pressure on the conical surface and releases the clamping between the friction ring and the synchronizer ring. Small elastic rebounds or contractions can be considered theoretically for simplicity.

This feature is due to the fact that the friction ring can be moved in the axial direction over a distance relative to the gear wheel.

The notches may simultaneously constitute a void of the engagement geometry. The friction ring can thus be produced particularly simply and economically.

The surfaces of the friction rings facing one another that adjoin the interruption can run parallel to one another or obliquely in the radial view. In the case of a parallel orientation of the faces, the friction ring can be produced particularly simply. If the surfaces run together at an angle to one another, in particular run conically, they can be used as functional surfaces, wherein the forces required for expanding and/or sliding the friction ring can be introduced at least partially into these functional surfaces. In addition, the conically inclined surface can further improve the release behavior after the synchronization process

Given that the friction surfaces are not completely separated by the friction ratio and that a residual clamping is maintained, the friction torque on the friction surfaces, which is supported on the inclined surfaces, causes a restoring movement due to the axial forces generated and the conical surfaces are disengaged from one another.

The surfaces of the friction ring adjoining the interruption extend at an acute angle to one another in a radial view, wherein the two surfaces are inclined in the longitudinal direction of the synchronization unit. The two surfaces are thus available for the introduction of forces. In particular, the notches are V-shaped.

Particularly preferably, the two surfaces adjoining the interruption are inclined to a different extent, viewed in the longitudinal direction of the synchronization unit. This results in an angular difference, by means of which the orientation, disengagement and shifting comfort are improved.

According to one embodiment, the recess is formed by a recess in the catch wheel, which recess opens in the axial direction of the synchronization unit towards the friction ring. The friction ring can therefore be simply slipped onto the gear wheel together with the projections provided thereon when the synchronization unit is assembled, in order to couple the gear wheel and the friction ring in the direction of rotation. At the same time, an axial stop for the friction ring can be formed by the recess. In particular, the recess and the projection are shaped in such a way that the projection can impinge on an end flank of the recess, in particular during a synchronization process.

The at least one protuberance may be disposed on an inner surface of the friction ring. Such a protuberance may be integral with the friction ring. The elevation enables a simple and reliable coupling of the friction ring with the catch wheel.

For example, the at least one elevation is provided on the inner surface of the friction ring and is provided directly adjacent to the interruption. This simplifies the demolding (Entformung) of the friction ring.

According to one embodiment, at least two elevations are provided on the inner surface of the friction ring, which elevations each directly adjoin the interruption, in particular one elevation on each side of the interruption. This has the following advantages: the spreading apart of the friction ring can be limited when the elevations engage in a corresponding recess in the catch wheel.

Alternatively or additionally, at least one elevation can be provided on that end side of the friction ring which is directed toward the catch wheel, and the recess can be formed by a corresponding notch, in other words a recess or a window, in the catch wheel. In this way, a secure coupling of the friction ring to the gear wheel in the direction of rotation can likewise be achieved. The gear wheel can in this case provide an axial stop against which the projection impinges.

For example, a latching geometry is formed on the free longitudinal end of the elevation, which latching geometry latches onto the catch wheel. In this way, the friction ring can be prevented from disengaging from the gear wheel too far in the axial direction. Furthermore, the friction ring can be detached from the synchronizer ring. Furthermore, a defined movability of the friction ring relative to the gear wheel in the axial direction can be determined by the detent geometry, i.e. the friction ring can be moved within a defined range in the axial direction relative to the gear wheel. Alternatively, the friction ring can be fixed in a defined axial position relative to the gear wheel by means of a bulge, in particular by means of a detent geometry. According to a further embodiment, an at least partially circumferential bead can be formed on the inner surface of the friction ring, which bead engages in a circumferential groove on the gear wheel. The friction ring can thus also be fixed to the gear wheel in the axial direction. The groove and the ledge can be designed as follows: the friction ring is movable in axial direction relative to the gear wheels by a defined amount.

In particular if the friction ring is a sheet metal part, the at least one elevation is formed, for example, by a tongue plate in the friction ring which is bent radially inward. In this way, the friction ring can be produced particularly economically.

According to one embodiment, the catch wheel can be formed with a bead which has at least one interruption running through in the circumferential direction in the axial and radial direction, which forms a recess into which a projection provided on the friction ring engages, wherein the bead provides an axial stop for the friction ring. The mobility of the friction ring in the axial direction is therefore limited by the raised edge. At the same time, the mechanical coupling of the friction ring and the gear wheel in the direction of rotation can be realized by the interruption in the raised edge.

The gear wheel is preferably multi-part, wherein it has a gear wheel and a clutch disk fastened thereto with a shifting toothing, wherein the at least one elevation or the at least one recess is present in the clutch disk. Complex geometries can also be realized in the gear wheels by means of a multi-part embodiment. For example, undercuts can be formed in the gear wheels in a simple manner, into which undercuts the latching geometry of the friction ring can latch. Furthermore, the shifting toothing can be produced from a different material than the gearwheel by means of a multi-part construction. This is advantageous in terms of the service life of the components and the material costs.

In order to achieve the greatest possible frictional force between the synchronizer ring and the friction ring during synchronization, a friction lining is provided, for example, on the contact surface between the synchronizer ring and the friction ring. The friction lining can be an additional friction layer, for example a carbon lining, or a groove on the friction ring and/or on the synchronizing ring.

A friction-reducing layer can be present at the contact surface between the gear wheel and the friction ring, whereby the disengagement of the frictional engagement can be simplified.

Drawings

Further advantages and features of the invention are obtained from the following description and from the following reference to the drawings. In the drawings:

fig. 1a to 7a and 9a to 10a each show an exploded view of an embodiment of a synchronization unit according to the invention;

fig. 1b to 7b and 9b to 10b show sectional views of the synchronization unit according to the invention shown in fig. 1a to 7a and 9a to 10a, respectively;

fig. 8a to 8e schematically show different latching geometries, which can be provided alternatively instead of the latching geometry shown in fig. 7.

Detailed Description

Fig. 1a shows an exploded view of a synchronization unit 10 according to the invention of a gear mechanism. The synchronizing unit 10 comprises a gear wheel 12, a friction ring 14 and a synchronizing ring 16.

As can be seen in the associated sectional view in fig. 1b, the gear wheel 12 is designed in multiple parts and comprises a gearwheel 22 and a clutch disk 24 with shifting teeth 26. The clutch disk 24 is firmly connected to the gear wheel 22, for example by means of a press fit or by welding.

The gear wheel 12 is mounted loosely on a shaft, not shown, and is driven by a gear wheel, also not shown for the sake of simplicity, during operation of the synchronization unit 10.

The synchronizer ring 16 is driven during operation of the synchronization unit 10 by a guide sleeve 27 which is connected in a rotationally fixed manner to a shaft, not shown, wherein the synchronizer ring 16 is mounted in a rotationally fixed manner relative to the guide sleeve 27 in the circumferential direction. The guide sleeve 27 is often also referred to as synchronization body.

In order to carry out the shifting operation, the synchronizing ring 16 must be rotated at the same speed as the gear wheel 12. This is achieved in that a sliding sleeve 28, which is shown in fig. 1b and can be brought into engagement with an outer toothing 30 of the synchronizer ring 16, moves the synchronizer ring 16 in the direction of the gear wheel 12. Only when the rotational speed of the synchronizer ring 16 is equal to the rotational speed of the gear wheel 12 can the sliding sleeve 28 additionally mesh with the shifting toothing 26 of the gear wheel 12 in order to mechanically couple the synchronizer ring 16 and the gear wheel 12.

The basic principle of operation of such a shifting process is known from the prior art as bogehner synchronization. The principle of action is therefore not described in detail below.

In the embodiment shown, in order to equalize the rotation speed of the synchronizer ring 16 with that of the gear wheel 12, the synchronizer ring 16 is not directly in frictional engagement with the gear wheel 12, but the synchronizer ring 16 is in frictional engagement with a friction ring 14, which is in turn mechanically coupled with the gear wheel 12.

The friction ring 14 is arranged radially inside the synchronizing ring 16. Furthermore, the friction ring 14 is arranged radially outside the gear wheel 12, in particular radially outside the conical surface 29 of the gear wheel 12.

The friction ring 14 is conical and tapers in the direction of the synchronizer ring 16, wherein the cone angle of the outer surface 18 of the friction ring 14 is smaller than the cone angle of the inner surface 20 of the friction ring 14. This can be seen in the sectional view of fig. 1 b. The taper angle of the outer surface 18 is, for example, between 1 ° and 6 °, while the taper angle of the inner surface 20 is between 5 ° and 15 °, particularly preferably between 7 ° and 12 °.

Due to the small taper angle on the outer surface 18 of the friction ring 14, the synchronizing ring 16 can be self-locking with the friction ring 14, so that a high friction torque can be transmitted, thereby accelerating the synchronization process.

In order to additionally increase the friction between the friction ring 14 and the synchronizing ring 16, a friction lining 32 is provided, which can be arranged on the inner surface of the synchronizing ring 16 and/or on the outer surface 18 of the friction ring 14. Alternatively, a slot may be provided instead of the friction lining 32.

The friction ring 14 is mechanically coupled, in particular in the direction of rotation, with the gear wheel 12 via the engagement geometry 34. In this case, however, a certain relative movement between the friction ring 14 and the gear wheel 12 can be achieved at least in the axial direction if the synchronizer ring 16 is not pressed against the gear wheel 12 or the friction ring 14 by the sliding sleeve 28.

The engagement geometry 34 comprises a bead 36 and a recess 38, wherein, in the embodiment shown in fig. 1a and 1b, the bead 36 is arranged on the catch wheel 12 and the recess is arranged on the friction ring 14.

The elevations 36 are in particular projections formed on the clutch disk 24 of the gear wheel 12.

The recess 38 is formed by an interruption 40 in the friction ring 14, that is to say by a through-opening 42 running axially and radially.

The mutually opposite surfaces 43 of the friction ring 14 adjacent to the interruption 40 extend parallel to one another in the radial view.

The principle of operation of the synchronization unit 10 according to the invention is briefly explained below.

During synchronization, the synchronizer ring 16 is moved in the axial direction towards the gear wheel 12, as already explained above. The frictional engagement between the synchronizer ring 16 and the friction ring 14 is achieved in that the friction ring 14 is pushed by the synchronizer ring 16 in the direction of the gear wheel 12 up to the axial stop 44 onto the conical surface 29 of the gear wheel 12. The friction ring 14, which is somewhat elastic due to the interruptions 40, is thereby spread open and pressed from the inside against the synchronizing ring 16. While pressing the synchronizer ring 16 in the axial direction toward the friction ring 14. In particular, the inner surface of the synchronizing ring 16 is pressed against the conical outer surface 18 of the friction ring 14. In this way, a high friction torque is achieved, as a result of which the rotational speed of the synchronizer ring 16 is equal to the rotational speed of the gear wheel 12. A certain frictional engagement between the friction ring 14 and the gear wheel 12 can of course also take place here. However, the friction ring 14 is coupled with the gear wheel 12 primarily by means of the engagement geometry 34.

The axial stop 44 can be formed by the conical surface 29 of the gear wheel 12 and/or by an axial limitation (Begrenzung) on the gear wheel 12. In the embodiment shown, in particular, the clutch disk 24 provides a stop surface 46 for the friction ring 14.

When the synchronizer ring is to be disengaged from the gear wheel 12 again, the friction ring 14 can initially move a distance with the synchronizer ring 16 due to the high friction between the friction ring 14 and the synchronizer ring 16. At the same time, the frictional engagement between the gear wheel 12 and the friction ring 14 is released to the greatest possible extent. In this state, the previously expanded friction ring 14 can be retracted somewhat due to its elasticity, so that the frictional engagement between the synchronizer ring 16 and the friction ring 14 can be released without a large expenditure of force. The greater taper angle on the inner surface 20 of the friction ring 14 also enables the frictional engagement between the friction ring 14 and the gear wheel 12 to be released with a lower force consumption. In this way, the shifting comfort can be increased.

The same reference numerals are used below for identical structures having the same function as known from the above-described embodiments and reference is made in this regard to the previous description, wherein the differences of the respective embodiments are discussed below to avoid redundancy.

Fig. 2 shows a further embodiment of the synchronization unit 10 according to the invention, wherein fig. 2a shows an exploded view of the synchronization unit 10 and fig. 2b shows a sectional view thereof. The synchronizer ring 16 is omitted from this view for simplicity, but may be constructed similarly to the synchronizer ring 16 shown in FIG. 1.

The embodiment of fig. 2 differs from the embodiment of fig. 1 in the form of the engagement geometry 34, in particular in the form of the interruption 40.

In the embodiment of fig. 1, the mutually facing surfaces 43 of the friction ring 14 adjoining the interruption extend parallel to one another in the radial view, whereas in the embodiment of fig. 2 the surfaces 43 are inclined to one another. In particular, the faces 43 extend at an acute angle to one another in a radial view, wherein both faces are inclined in the longitudinal direction of the synchronization unit 10. In other words, the passage notches 42 (by which the interruptions 40 are formed) are V-shaped.

The protuberance 36 formed on the gear wheel 12 is shaped in correspondence with the interruption 40, that is to say it becomes smaller in the radial direction towards the friction ring 14.

The surface 43 can be used as a functional surface by the engagement geometry 34 formed in this way, wherein the forces required for expanding and/or sliding the friction ring 14 can be introduced into these functional surfaces via the elevations 36. In this way, the frictional engagement between the friction ring 14 and the synchronizing ring 16 can be additionally improved. In addition, the conical inclined surface can further improve the release characteristics after the synchronization process.

Fig. 3 shows a further embodiment of the synchronization unit 10 according to the invention, wherein fig. 3a shows an exploded view of the synchronization unit 10 and fig. 3b shows a sectional view thereof.

The embodiment of fig. 3 differs from the previous embodiments essentially in the form of the engagement geometry 34.

In the synchronization unit 10 shown in fig. 3, the engagement geometry 34 comprises: two recesses 38, which are provided on the gear wheel 12, in particular on the gear wheel 22; and a plurality of protuberances 36 which are provided on the radially inner surface 20 of the friction ring 14 and which can engage into the recesses 38 in order to mechanically couple the friction ring 14 in the direction of rotation with the gear wheel 12.

Here, two elevations of the plurality of elevations 36 are each arranged directly adjacent to the interruption 40. In particular, one elevation 36 is provided on each side of the interruption 40.

Both the elevations 36 arranged on both sides of the interruption 40 engage in the same interspace 38. This limits, in particular prevents, the friction ring 14 from spreading apart by centrifugal force in that the bead 36 bears laterally against the recess 38 and thus supports the slotted friction ring 14.

The recess 38 opens in the direction of the friction ring 14. In this way, the friction ring 14 can be inserted onto the gear wheel 12 in a simple manner when the synchronization unit is assembled. In addition, a certain axial mobility of the friction ring 14 relative to the gear wheel 12 can be achieved in this way.

In addition, the recess 38 also provides an axial stop surface 46 for the friction ring 14, which is formed by the end side of the recess 38.

The recess 38 is designed as a recess 39, in particular a cavity, in the gear wheel 12.

Fig. 4 shows a further embodiment of the synchronization unit 10 according to the invention, wherein fig. 4a shows an exploded view of the synchronization unit 10 and fig. 4b shows a sectional view thereof.

The synchronization unit 10 of fig. 4 is constructed similarly to the synchronization unit 10 of fig. 3.

In contrast to the embodiment shown in fig. 3, an additional groove 48 is provided in the gear wheel 12 and an at least partially circumferential bead 50 is provided on the inner surface 20 of the friction ring 14, which bead 50 engages in the groove 48. In this way, the friction ring 14 is fixed to the gear wheel 12 in the axial direction.

As can be seen in fig. 4b, the groove 48 is slightly longer in the axial direction than the ledge 50, so that the friction ring 14 can move a defined distance in the axial direction.

In the embodiment shown, the circumferential bead 50 is interrupted only by the bead 36 and the interruption 40. The circumferential groove 48 on the gear wheel 12 is interrupted only by the recess 38.

Fig. 5 shows a further embodiment of the synchronization unit 10 according to the invention, wherein fig. 5a shows an exploded view of the synchronization unit 10 and fig. 5b shows a sectional view thereof.

In the synchronization unit of fig. 5, the engagement geometry 34 comprises a plurality of elevations 36 which are arranged on the gear wheel 12 and are distributed uniformly in the circumferential direction.

A plurality of recesses 38 are correspondingly provided on the friction ring 14, wherein one of the recesses 38 is formed by a discontinuity 40, while the remaining recesses 38 are formed by radial recesses on the inner surface 20 of the friction ring 14.

Fig. 6 shows a further embodiment of the synchronization unit 10 according to the invention, wherein fig. 6a shows an exploded view of the synchronization unit 10 and fig. 6b shows a sectional view thereof.

In this embodiment of the synchronization unit 10, a plurality of elevations 36 are provided, which are arranged on the end side of the friction ring 14 facing the catch wheel 12.

The recesses 38 are each formed by a corresponding slot 52, in other words a recess or window, in the catch wheel 12. The recess 38 can have a defined depth in the axial direction, so that the bottom surface of the recess 38 can each serve as an axial stop surface 46 for the friction ring 14.

In the embodiment shown in fig. 6, the recess 38, in particular the slot 52, is provided in the clutch disk 24, wherein the slot 52 is formed completely through the clutch disk 24 in the axial direction. The bottom of the recess 38 is thus formed by the toothed wheel 22, so that the toothed wheel 22 provides an axial stop surface 46 for the friction ring 14.

Fig. 7 shows a further embodiment of the synchronization unit 10 according to the invention, wherein fig. 7a shows an exploded view of the synchronization unit 10 and fig. 7b shows a sectional view thereof.

The synchronization unit 10 shown in fig. 7 constitutes a modification of the synchronization unit 10 shown in fig. 6.

In this case, a latching geometry 54 is formed on each free longitudinal end of the elevations 36, which latches onto the catch wheel 12, in particular onto the clutch disk 24. In this way, the friction ring 14 is fixed to the gear wheel 12 in the axial direction, wherein the friction ring 14 can move axially to a limited extent relative to the gear wheel 12. For example, the latching geometries 54 are each formed by latching lugs.

Correspondingly, a plurality of undercuts 56 are provided on the gear wheel 12, into which undercuts the elevations 36, in particular the latching geometries 54, can latch.

In the embodiment shown, the undercut 56 is formed by recesses 58 in the gear wheel 12, in particular in the gear wheel 22, which recesses are open toward the friction ring 14 and are partially covered by the clutch disk 24. In this case, the recess 38 or the groove 52 is provided so as to be covered by the indentation 58, so that the elevation 36 can engage in the indentation 58.

The bottom of the recess 58 can form an axial stop surface 46 for the friction ring 14.

The friction ring 14 shown in fig. 1 to 7 is, for example, a powder metal part (pulvermetalltoil).

Fig. 8a to 8e each schematically show a sectional view of a friction ring 14 with different latching geometries 54, which can be considered as alternatives to the latching geometries 54 shown in fig. 7.

In particular, fig. 8a shows a latching geometry 54 in the form of a projection. Fig. 8b shows a latching geometry 54 similar to the latching lug in fig. 7. Fig. 8c shows a latching geometry 54 in the form of a pawl. Fig. 8d and 8e show a detent geometry 54 in the form of a lug (Flansch), which in fig. 8d is arranged on the inner surface 20 of the friction ring 14 and in fig. 8e on the outer surface 18 of the friction ring.

Fig. 9 shows a further embodiment of the synchronization unit 10 according to the invention, wherein fig. 9a shows an exploded view of the synchronization unit 10 and fig. 9b shows a sectional view thereof.

The engagement geometry 34 of the synchronization unit 10 shown in fig. 9 comprises a plurality of elevations 36, each of which is formed by a radially inwardly bent tongue 60 in the friction ring 14. The elevation 36 or the tongue 60 is arranged here on the end face of the friction ring 14 that is distal from the gear wheel 12. In addition, the elevations 36 are preferably distributed uniformly over the friction ring 14 in the circumferential direction.

In each case, a plurality of recesses 38 are formed in the gear wheel 12, in particular in the gearwheel 22, into which recesses the elevations 36 engage. The recess 38 is formed here by a rectangular cutout in the catch wheel 12, viewed in the radial direction. The bottom surface of the recess, which faces axially toward the friction ring 14, provides an axial stop surface 46 for the friction ring 14.

Fig. 10 shows a further embodiment of the synchronization unit 10 according to the invention, wherein fig. 10a shows an exploded view of the synchronization unit 10 and fig. 10b shows a sectional view thereof.

The friction ring 14 of the synchronization unit 10 shown in fig. 10 is similar to the friction ring 14 shown in fig. 9, except for the length of the tongue plate 60.

Furthermore, a flange 62 is formed on the gear wheel 12, which flange has a plurality of axially and radially continuous interruptions 64 in the circumferential direction, which form the recesses 38 of the engagement geometry 34.

As can be seen in fig. 10b, the bead 62 here provides an axial stop for the friction ring 14. In particular, the ledge 62 cooperates with the stop surface 46 on the gear wheel 12 to limit the freedom of movement of the friction ring 14 in the axial direction.

The friction ring 14 shown in fig. 9 and 10 is, for example, a sheet metal part.

The invention is not limited to the embodiments shown. In particular, individual features of one embodiment can be included in a further embodiment according to the invention independently of other features of the respective embodiment, that is to say the features described can be combined arbitrarily.

Claims (19)

1. A synchronization unit (10) for a transmission, comprising a gear wheel (12), a synchronization ring (16) and a friction ring (14),

wherein the friction ring (14) is frictionally engageable with the synchronizer ring (16) and directly engageable with the gear wheel (12) by means of an engagement geometry (34) comprising at least one recess (38) and at least one elevation (36) in such a way that the elevation (36) engages into the recess (38) and the friction ring (14) is mechanically coupled with the gear wheel (12) in the direction of rotation,

wherein the at least one elevation (36) is arranged on the friction ring (14) or on the gear wheel (12) and the at least one recess (38) is arranged on the respective other element of the friction ring (14) and the gear wheel (12),

and the friction ring (14) has a radially inner surface (20) and a radially outer surface (18) which each diverge at a cone angle,

wherein the taper angle of the inner surface (20) is different from the taper angle of the outer surface (18).

2. The synchronization unit (10) according to claim 1, characterized in that: the taper angle of the outer surface (18) of the friction ring (14) is less than the taper angle of the inner surface (20) of the friction ring (14).

3. Synchronization unit (10) according to any of the preceding claims, characterized in that: the outer surface (18) of the friction ring (14) has a cone angle which differs from the cone angle of the inner side of the synchronizing ring (16), in particular by more than 1 °.

4. Synchronization unit (10) according to any of the preceding claims, characterized in that: an axial stop (46) is provided in order to limit the mobility of the friction ring (14) in the axial direction relative to the gear wheel (12) or to fix the friction ring (14) firmly in the axial direction on the gear wheel (12).

5. Synchronization unit (10) according to any of the preceding claims, characterized in that: the friction ring (14) is located radially inside the synchronizing ring (16).

6. Synchronization unit (10) according to any of the preceding claims, characterized in that: the friction ring (14) has a circumferential interruption (40) which is formed by an axially and radially continuous groove (42) in the friction ring (14).

7. Synchronization unit (10) according to claim 6, characterized in that: the surfaces (43) of the friction ring (14) that are opposite to each other and adjacent to the interruption (40) extend parallel to each other or obliquely in a radial view.

8. Synchronization unit (10) according to claim 7, characterized in that: the surfaces (43) of the friction ring (14) adjoining the interruption (40) extend at an acute angle to one another in a radial view, wherein both surfaces are inclined in the longitudinal direction of the synchronization unit (10).

9. Synchronization unit (10) according to any of the preceding claims, characterized in that: the recess (38) is formed by a recessed section (39) in the catch wheel (12), which is open in the axial direction of the synchronization unit (10) towards the friction ring (14).

10. Synchronization unit (10) according to any of the preceding claims, characterized in that: the at least one protuberance (36) is disposed on the inner surface (20) of the friction ring (14).

11. Synchronization unit (10) according to any one of claims 6 to 9, characterized in that: the at least one elevation (36) is arranged on the inner surface (20) of the friction ring (14) and is arranged directly adjacent to the interruption (40).

12. Synchronization unit (10) according to any one of claims 6 to 11, characterized in that: at least two elevations (36) are arranged on the inner surface (20) of the friction ring (14), which elevations are in each case directly adjacent to the interruption (40), in particular one elevation (36) being arranged on each side of the interruption (40).

13. Synchronization unit (10) according to any of the preceding claims, characterized in that: the at least one elevation (36) is arranged on the end face of the friction ring (14) facing the catch wheel (12), and the recess (38) is formed by a corresponding recess (52) in the catch wheel (12).

14. The synchronization unit (10) according to claim 13, characterized in that: a latching geometry (54) is formed on the free longitudinal end of the projection (36) and latches onto the catch wheel (12).

15. Synchronization unit (10) according to any of the preceding claims, characterized in that: an at least partially circumferential bead (50) is formed on the inner surface (20) of the friction ring (14) and engages in a circumferential groove (48) on the gear wheel (12).

16. Synchronization unit (10) according to any one of claims 1 to 12, characterized in that: the friction ring (14) is a sheet metal part, wherein the at least one elevation (36) is formed by a tongue (60) in the friction ring (14) which is bent radially inward.

17. Synchronization unit (10) according to any of the preceding claims, characterized in that: a flange (62) is formed on the gear wheel (12), said flange having at least one axially and radially continuous interruption (64) in the circumferential direction, said interruption forming the recess (38) into which a projection (36) provided on the friction ring (14) engages, wherein the flange (62) provides an axial stop for the friction ring (14).

18. Synchronization unit (10) according to any of the preceding claims, characterized in that: the selector wheel (12) is multi-part and has a toothed wheel (22) and a clutch disk (24) fastened to the toothed wheel (22) and having a shifting toothing (26), wherein the at least one elevation (36) or the at least one recess (38) is present in the clutch disk (24).

19. Synchronization unit (10) according to any of the preceding claims, characterized in that: a friction lining (32) is present at the contact surface between the synchronizer ring (16) and the friction ring (14).

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