EP2044350A2

EP2044350A2 - Parking lock for a transmission

Info

Publication number: EP2044350A2
Application number: EP07765722A
Authority: EP
Inventors: Heinz Reichert
Original assignee: ZF Friedrichshafen AG
Current assignee: ZF Friedrichshafen AG
Priority date: 2006-07-22
Filing date: 2007-06-29
Publication date: 2009-04-08
Also published as: KR20090034991A; JP5069747B2; WO2008012168A2; JP2009544515A; DE102006033985A1; WO2008012168A3; US20090314604A1; CN101490448A; DE102006033985B4; US8225921B2

Abstract

The present invention relates to a parking lock of a transmission having a ramp (10) for pressing against an actuating element, wherein the ramp (10) has an actuating direction (11), in which the actuating element can be moved, and a ramp gradient in the actuating direction (11). According to the invention, the ramp (10) has a ramp gradient which varies transversely with respect to the actuating direction (11). By means of the invention, the loading of a pawl (1) and of the actuating element can be reduced.

Description

Parking lock for a transmission

The present invention relates to a parking lock of a transmission with a ramp for pressing an actuating element, wherein the ramp has an actuating direction, in which the actuating element is movable, and a ramp gradient in the actuating direction.

Different parking locks for automatic transmissions are known from the prior art. Thus, DE 197 44 238 A1 describes a parking brake with a pawl which can be pivoted from a neutral position into a blocking position in which engages a locking tooth on the pawl in a detent recess on a locking ring on the drive shaft of a transmission. For pivoting the pawl, a displaceable cam part is provided, which presses in response to its position against the locking tooth facing away from the pawl. On the pawl, a ramp is further provided, which has a constant ramp slope in the Betäfigungsrichtung and over the entire width of the ramp Here, the direction of actuation is that direction in which the cam member is moved to pivot the pawl in the locked position. In the direction of actuation, the ramp then merges into a supporting surface. The ramp serves to effect a smooth and easy movement of the cam member and the pawl. A similar parking brake is also known from DE 199 33618 A1.

From US 2001/0042669 A1 a similar parking lock is known, wherein the ramp against which presses the cam member is formed by a slope at the free end of the pivotable pawl. Furthermore, the actuation of the pawl takes place relative to the pivot axis of the same ben in the radial direction, which is why one speaks of a radial pawl operation

The parking lock known from the prior art have the disadvantage that at the points of contact between the actuator in the form of a cam part o. Ä. And the ramp surface particularly high loads occur, thereby making difficult for a movement of the pawl and the actuating element and the other Functioning of said components is at risk.

The present invention is therefore an object of the invention to provide a parking brake of a transmission with a ramp for pressing an actuator, occur in the lower loads on the pawl and the actuator, so that the movement of said parts can be easily performed and a long-lasting Functionality is guaranteed

The solution of this problem is based on the features specified in the claims. Advantageous embodiments of the invention are the subject of the dependent claims.

The parking brake according to the invention of a transmission has a ramp to which an actuating element for pivoting the pawl can be pressed. The ramp may for example be formed integrally with the pawl by a corresponding slope is provided on the pawl. Alternatively or additionally, this ramp can also be depicted in a guide plate of a parking lock or a housing. The ramp has an actuating direction. The direction of actuation of the ramp is that predetermined direction in which the actuating element is moved in order to pivot the pawl from a neutral position to a blocking position. Furthermore, the ramp in this operating tion direction on a ramp slope. According to the invention, the ramp has a ramp gradient which changes transversely to the actuating direction. This means, for example, that the magnitude of the ramp gradient in the direction of actuation depends on the point at which the ramp slope is measured in the width direction of the ramp.

While the actuating elements for the parking locks according to the prior art always abut punctiform on the ramp, which leads to greater loads at this point, is achieved by changing transversely to the direction of actuation ramp slope that the actuator, for example, an adjacent to the ramp role comprises, at least at the same time at two or more points or even linearly applied to the ramp This reduces the burden on both the pawl / guide plate or the housing as well as for the adjacent actuator. As a result, a simpler relative movement and a lower wear on the components is achieved.

In a preferred embodiment of the parking lock according to the invention, the ramp has a transversely to the operating direction continuously changing ramp slope, whereby the aforementioned advantages are enhanced.

In order to achieve a linear support of the actuating element on the ramp independently of the pivoting position of the parking lock, the ramp forms a ramp surface in a particularly preferred embodiment of the parking lock according to the invention, to which the actuating element can be pressed, wherein the ramp surface is formed as a helical surface. According to an advantageous embodiment of the parking lock according to the invention, the pawl of the parking brake on a storage end, by means of which the pawl can be mounted pivotably about a pivot axis. The bearing end may comprise, for example, a cylindrical bore, via which the pawl can be mounted on a pivot pin or the like, which forms the pivot axis.

In a particularly advantageous embodiment of the parking lock according to the invention, the ramp slope increases to the bearing end remote from the side of the ramp. In this way, it is ensured that the actuating element can continue to rest linearly on the ramp or ramp surface, even if the pawl of the parking brake is pivoted into different pivot positions.

In a further preferred embodiment of the parking lock according to the invention, the actuating direction of the ramp runs parallel to the pivot axis of the pawl which can be generated with the aid of the bearing end. The pawl with its ramp is therefore designed for a parking brake with axial pawl operation.

In order to prevent further pivoting of the pawl by the actuating element after reaching the blocking position, a planar support surface is provided in a further advantageous embodiment of the parking lock according to the invention on the pawl / guide plate or on the housing, which adjoins the ramp at an angle in the direction of actuation. The support surface formed in just to achieve in this area a linienförmi- ge support of the actuating element when the actuator comprises the aforementioned cylindrical rollers or similar adjacent to the Absfützfläche parts. According to a further advantageous embodiment of the parking lock according to the invention, the pawl has a latching tooth, which is arranged on the side facing away from the ramp and / or support surface of the pawl. Such a locking tooth can, for example, engage in a detent recess in a parking lock gear on the output shaft of a transmission when the detent pawl is in the blocking position

In a further preferred embodiment of the parking lock according to the invention, the planar support surface is arranged parallel to the longitudinal direction of the latching tooth

The parking brake according to the invention for a transmission has a pawl, a guide plate or a housing with a ramp of the type described above, wherein the pawl is pivotally mounted about a pivot axis. Furthermore, the parking brake comprises an actuating element, which in the direction of actuation of the ramp from a first position, in which the pawl is in a neutral position, via a second position, in which the actuating element presses against the ramp in such a way that the pawl is pivoted into an intermediate position, can be moved to a third position in which the pawl is pivoted to a locking position in which the transmission is locked. In the neutral position there is no locking of the gearbox,

In a preferred embodiment of the parking lock according to the invention the actuating element is supported in the third position on the support surface.

In a particularly preferred embodiment of the parking lock according to the invention the actuating element and the ramp are designed and matched to one another that the actuating element in the second Position is always pressed line-shaped against the ramp regardless of the pivotal position of the pawl, Preferably, the linear support should be made over the entire width of the supported part of the actuating element.

In a further particularly preferred embodiment of the parking lock according to the invention, the actuating element has at least one roll which can be unrolled on the ramp. As a result, the relative movement of the pawl and actuating element to each other is substantially simplified. The role may be formed for example as a cylindrical roller.

In a further advantageous embodiment of the parking lock according to the invention a non-rotatably connected to the output shaft of a transmission parking lock gear is provided, wherein the pawl in the locked position with the parking lock gear is engaged. As a result, further rotation of the output shaft is reliably prevented in the blocking position of the pawl.

The invention will be explained in more detail below with reference to an exemplary embodiment with reference to the accompanying drawings. Show it:

1 is a perspective view of an embodiment of the pawl of the invention a parking brake,

2 is an enlarged view of the ramp of the pawl of Fig. 1,

Fig. 3 is a partial side view of a parking brake with the

Pawl of FIGS. 1 and 2, wherein the actuating is shifted to a first position while the pawl is pivoted to the neutral position,

Fig. 4, the parking brake of Fig. 3, wherein the actuating element is moved to a second position, while the pawl is pivoted to an intermediate position and

Fig. 5, the parking brake of Fig. 4, wherein the actuating element is displaced to a third position, while the pawl is pivoted into the locked position.

Hereinafter, the embodiment of the pawl 1 according to the invention for the parking brake of a transmission will first be described with reference to FIGS. 1 and 2. The pawl 1 is designed as an elongated lever which comprises a bearing end 2 and a free end 3 in the installed state. In the bearing end 2, a cylindrical, continuous bore 4 is provided, by means of which the pawl 1 on a pivot (not shown) o can be stored, so that the pawl 1 can be pivoted about a pivot axis, which is indicated in the figures by the reference numeral 5

In the region of the free end 3, an elongate detent tooth 7 is provided on the one side 6 of the locking line 1, wherein the longitudinal direction 8 of the detent tooth 7 extends parallel to the pivot axis 5. On the other side 8 of the pawl 1, which faces away from the side 7, a ramp 10 is arranged. The ramp 10 is used for pressing an actuating element for pivoting the pawl 1 about the pivot axis 5, as will be explained later with reference to FIGS. 3 to 5. The ramp 10 in this case has a vorbesfimmte Betäfigungsrichtung 11, in which the actuator is to be moved. Under the direction of actuation 11 of the ramp 10 is denje- nige predetermined direction to understand, in which the actuating element is moved to pivot the pawl 1 from a neutral position to a locking position. The ramp 9 forms a ramp surface 12 which, based on the actuation direction, is surrounded by two lateral edges 13, 14, a front edge 15 and a rear edge 16. The ramp surface 12 is inclined relative to the actuation direction 11, so that the ramp 9 has a Ramp slope in the direction of actuation 11 has.

The ramp 9 in this case has a ramp gradient in the direction of actuation 10, which changes transversely to the actuation direction 11, that is from the one lateral edge 13 to the other lateral edge 14 in the width direction, as will be explained in more detail below with reference to FIG. The ramp slope changes continuously. This is achieved in the present embodiment, characterized in that the ramp surface 12, to which the actuating element can be pressed, as a screw surface between the two lateral edges 13, 14 is formed. Thus, one lateral edge 13 has a pitch angle αi with respect to the actuating direction 11, while the other lateral edge 14 has a pitch angle Ct ₄ with respect to the actuating direction 11, wherein α _{4 is} greater than O ₁ . The ramp slope is therefore increased to the storage end 2 side facing away from the ramp 10. The ramp slope in the region between the lateral edges 13, 14 assumes, due to the ramp surface 12 formed as a screw surface, values which lie between the pitch angles αi and α ₄ , as shown by way of example by the pitch angles O ₂ and Ö ₃ in FIG. 2 , For these, O ₄ > α ₃ > Ö ₂ > αi

The actuation direction 10 of the ramp 9 runs parallel to the pivot axis 5 of the pawl which can be generated with the aid of the bearing end 2, as can be seen from FIG. It is therefore a pawl 2, which is designed for a parking brake with axial pawl operation. To the Rear edge 16 of the ramp surface 12 is followed by a flat support surface 17, which is aligned at an angle to the ramp surface 12 and extends parallel to the longitudinal direction 8 of the ratchet tooth 8.

Hereinafter, an embodiment of the parking lock 18 according to the invention with the pawl of FIGS. 1 and 2 with reference to Figs. 3 to 5 will be described. The parking brake 18 has, in addition to the pawl 1, an actuating element 19. The actuating element 19 comprises a push / pull rod 20, by means of which a roller packet 21 arranged at the end of the push / pull rod 20 can be displaced in the direction of actuation 11. The roller package 21 comprises a first cylindrical roller 22 and a second cylindrical roller 23, which are arranged transversely to the actuating direction 11, parallel to each other and rotatable on the roller package 21. The first roller 22 is supported on a housing 24 of a transmission or the parking lock 18, while the second roller 23 of the ramp 10 faces the pawl. The side 6 of the pawl 1 faces the circumference of a parking lock gear rotatably connected to the output shaft of a transmission, was waived their representation.

In Fig. 1, the actuating element 19 is in a first position. The second roller 23 exerts no pressure on the ramp 10 or the ramp surface 12 in this position.

Now, the actuating element 19 is displaced in the actuating direction 11 in a second position, which is shown in Fig. 4. In the second position, the second roller 23 presses against the ramp surface 12 of the pawl 1, so that the pawl 1 is pivoted about the pivot axis 5 in an intermediate position. The second roller 23 rolls off on the ramp surface 12. Thanks to the ramp surface formed as a screw surface 12, the second roller 23 is in the second position of the actuating element 19 regardless of the respective pivoting position of the pawl 1 always linear to the ramp surface 12, as indicated by the straight line 25, which extends along the normal of the plane of the drawing.

If the actuating element 19 is displaced further in the direction of actuation 11, the second roller 23 rolls over the rear edge 18 of the ramp surface 12 and is finally supported in the third position, which is shown in FIG. 5, on the support surface 17. The pawl 1 is in the third position of the actuating element 19 is already pivoted to a locking position, in which engages the locking tooth 7 in the parking lock gear, not shown, so that the transmission is locked

reference numeral

1 pawl

2 storage end

3 free end

4 hole

5 pivot axis

6 side of the pawl

7 locking tooth

8 longitudinal direction of the ratchet tooth

9 side of the pawl

10 ramp

11 operating direction of the ramp

12 ramp area

13 lateral edge

14 lateral edge

15 front edge

16 rear edge

17 support surface

18 parking lock

19 actuator

20 push / pull rod

21 roll package

22 first role

23 second role

24 housing

25 line

Claims

claims

A parking brake of a transmission having a ramp (10) for pressing an actuating element which may be arranged on a pawl (1), a housing (24), a guide plate or a combination thereof, wherein the ramp (10) has an actuation direction (11 ), in which the actuating element is movable, and a ramp gradient in the direction of actuation (11), characterized g eken n zei ch n et that the ramp (10) has a transversely to the BetätigungsriGhtung (11) changing ramp slope.

2. Parking lock according to claim 1, characterized Porsche Style nzeich that the ramp (10) has a transversely to the actuating direction (11) continuously changing ramp slope.

3. Parking brake according to one of claims 1 or 2, characterized geke n nzei ch n et that the ramp (10) forms a ramp surface (12) to which the actuating element is pressed, wherein the ramp surface (12) is designed as a helical surface,

4. Parking brake according to one of the preceding claims, characterized geke n nzeich n et that a pawl (1) of the parking brake has a storage end (2) by means of which the pawl (1) about a pivot axis (5) is pivotally mounted.

5. parking brake according to claim 4, characterized Porsche Style nzeich net that increases the ramp slope to the storage end (5) of the pawl (1) facing away from the ramp (10).

6. parking brake according to one of claims 4 or 5, characterized geke n nzei ch n et, that the actuating direction (11) of the ramp (10) parallel to the pivotable with the aid of the bearing end (2) pivot axis (5) of the pawl (1} runs.

7. A parking brake according to one of the preceding claims, characterized geke n nzei ch n et, that on the pawl (1) a flat support surface (17) is provided, which adjoins the ramp (10) in Betäfigungsrichtung (11).

8. Parking brake according to one of the preceding claims, characterized geke n nzei ch et n, that the pawl {1) has a latching tooth (7) on the ramp (10) and / or support surface (17) facing away from (9) the pawl (1) is arranged,

9. parking brake according to claim 8, characterized Porsche Style nzeich net that the flat support surface (17) is arranged parallel to the longitudinal direction (8) of the latching tooth (7).

10. Parking lock for a transmission with a pawl (1) which is pivotable about a pivot axis (5), and a Betägigungselement (19), wherein the actuating element (19) in the actuating direction (11) of the ramp (10) from a first position in which the pawl (1) is in a neutral position, via a second position, in which the actuating element (19) presses against the ramp (10) in such a way that the pawl (1) is pivoted to an intermediate position, into a third position is movable, in which the pawl (1) is pivoted to a locking position in which the transmission is locked.

11. Parking brake according to claim 10, characterized in that the actuating element (19) in the third position on the Abstützflä- (17)

12. Parking brake according to one of claims 10 or 11, characterized in that the actuating element (19) in the second position is always pressed linearly against the ramp (10) independently of the pivoting position of the pawl (1) ,

13. Parking brake according to one of claims 10 to 12, characterized geke n nzei ch n et that the actuating element (19) at least one on the ramp (10) unrolled bare role (23)

14. Parking brake according to one of claims 10 to 13, characterized g e - ke n nzei ch n et that a rotatably connected to the output shaft of a transmission parking lock gear is provided, wherein the pawl (1) in the locked position with the parking lock gear is engaged