Parking lock for a motor vehicle transmission

Abstract

The invention relates to a parking lock for a motor vehicle transmission. The parking lock is equipped with a claw assembly which is mounted coaxially with respect to a parking lock wheel and has at least one locking tooth on an end face, which is designed for positive engagement with the parking lock wheel; an actuator for moving the claw assembly so that it can be reversibly brought into engagement with the parking lock wheel via the at least one locking tooth; and a movable transmission means which transmits the movement of the actuator to the claw assembly, wherein the movable transmission means and the claw assembly are mounted axially displaceably by means of a guide device.

Description

[0001] The present invention relates to a parking lock for a motor vehicle transmission. State of the art

[0002] A parking lock on a motor vehicle transmission is a device that can prevent a vehicle from rolling away. When a vehicle is parked on a slope, for example, the vehicle's weight, depending on the wheel diameter, the gear ratio, and the radius of the parking lock gear (locking teeth), exerts a force on the closed pawl and thus, in turn, on the parking lock mechanism. The parking lock must therefore be able to withstand this applied force.

[0003] Corresponding parking lock mechanisms are widely known in the art. They typically comprise a pawl pivotally mounted on a pawl pin, which can engage or disengage a parking lock gear connected to the transmission output, and a locking element arranged on a connecting rod to a shift lever mounted on a pin. In the locked state, the locking element is clamped between the pawl and a guide plate to prevent the pawl from being forced out of a tooth gap in the parking lock gear. The locking element is spring-loaded on the connecting rod via a spring element, with the end of the connecting rod facing away from the locking element being hinged to the shift lever.

[0004] For example, the documents DE 10 2014 218 093 A1 and DE 10 2020 123 613 A1 describe a parking lock with claws for engaging in the parking lock gear. Disclosure of the invention

[0005] The invention provides a parking lock for a motor vehicle transmission having the features of claim 1.

[0006] According to a first aspect of the invention, a parking lock for a motor vehicle transmission is provided. The parking lock comprises a claw device, which is mounted coaxially with respect to a parking lock gear and has at least one locking tooth on one end face, which is designed for positive engagement with the parking lock gear, as well as an actuator for displacing the claw device so that it can be reversibly brought into engagement with the parking lock gear by means of the at least one locking tooth. Furthermore, the parking lock comprises a movable transmission means, which transmits the movement of the actuator to the claw device, wherein the movable transmission means and the claw device are mounted for axial displacement by means of a guide means.

[0007] One idea underlying the present invention is to provide a compact design for the parking lock within a so-called dead space of a motor vehicle transmission in order to optimally utilize the available installation space. The parking lock gear is known in this case. The parking lock gear can be dimensioned in diameter and / or tooth width depending on the load and requirements. The claw device with the at least one locking tooth has the function of blocking the parking lock gear and can thus fulfill the same function as the previously conventional pawl. The movable transmission means or the shift fork can, in particular, provide the same function as the cone of a known parking lock with a pawl.

[0008] Advantageously, the parking lock according to the invention can transmit higher loads and achieve shorter shift times while maintaining the same compact size, particularly compared to a known parking lock with a pawl. A large part of the parking lock mechanism can be arranged in the dead space of the motor vehicle transmission between the parking lock gear and a pinion, thus providing a compact design.

[0009] A further advantage is that by reducing the gear width, the axial stroke of the claw device is reduced. This allows for a rapid engagement time of the parking lock. Furthermore, the parking lock according to the invention can provide low load for the bearings of a pinion shaft of the motor vehicle transmission, since only a torsional moment acts on the parking lock gear during the positive engagement of the claw device with the parking lock gear.

[0010] Advantageous embodiments and further developments emerge from the further subclaims and from the description with reference to the figures of the drawing.

[0011] According to a further development of the parking lock, the movable transmission means comprises a spindle and a spindle nut, wherein the spindle is drivable by the actuator and extends parallel to a drive shaft of the motor vehicle transmission. Due to the self-locking nature of the spindle drive, the movable transmission means cannot be displaced inadvertently or due to component failure. The spindle nut and the spindle can thus move or actuate the locking tooth and bring it into position, i.e., into engagement with the parking lock gear. The spindle nut and the spindle can, in particular, provide the same function as the rod in a known parking lock with a pawl. Preferably, the spindle nut is integrated into the movable transmission means or into the shift fork.

[0012] For example, the spindle can be supported by two ball bearings. Furthermore, the spindle can have a groove on the front side facing the actuator. The groove can be designed to transfer torque from the actuator to the spindle.

[0013] According to a further development of the parking lock, the claw device has at least two locking teeth, preferably four to eight locking teeth, on the front side. In this way, several locking teeth can engage with the parking lock gear in the axial direction. Thus, the load for locking the motor vehicle transmission can be distributed across several locking teeth. Consequently, the parking lock can transmit higher loads, meaning it offers the potential for high torques. While simultaneously reducing the gear width on the parking lock gear, it also reduces shifting times because the path for engaging and disengaging the locking teeth is shorter than with a conventional parking lock with a pawl.

[0014] According to a further development of the parking lock, the movable transmission means is coupled to a locking element pivotably mounted on the transmission housing, wherein the locking element axially fixes the claw device in a parked state. The locking element or the locking lever can thus lock the claw device in the parked state. The locking element can be mounted on a pin. The pin can be mounted at both ends in a transmission housing of the motor vehicle transmission. The pin can be designed to mount the locking element in a rotationally fixed, i.e., pivotable, manner and to absorb an axial force from the claw device.

[0015] According to a further development of the parking lock, the movable transmission means is coupled to the engaging element by means of a hook-shaped connecting element for pivoting the engaging element. This means that the engaging element or the locking lever is connected to the movable transmission means or the shift fork by the hook-shaped connecting element or the hook. One end of the hook is mounted on the locking lever in a rotationally fixed, i.e. pivotable, manner, and the other end is also mounted on the shift fork in a rotationally fixed, i.e. pivotable, manner and axially displaceable manner. The hook enables the locking lever to be opened by actuating the shift fork and releases the claw device, thus enabling displacement of the claw device in the axial direction.

[0016] According to a further development of the parking lock, the locking element is pivotally mounted under spring load and has a projection as a stop for the locking element in the parked state. The projection or stop can prevent the locking element from falling out of the movable transmission means. A spring provides the spring load for the locking element and is designed to ensure that the locking element remains preloaded and engages when the claw device is engaged, securing the axial position of the claw device.

[0017] According to a further development of the parking lock, an axial movement of the movable transmission means is limited by a retaining ring which is mounted on the guide device.

[0018] According to a further development of the parking lock, the movable transmission means comprises a compression spring device that transmits a transmission force to the claw device. The compression spring device can preload the claw device and / or the locking tooth. The compression spring device can, for example, comprise a spiral spring or a comparable compression spring. The compression spring device can, in particular, provide the same function as the conical spring of a known parking lock with a locking pawl.

[0019] According to a further development of the parking lock, the claw device contains a locking ring as a stop for the movable transmission means, so that when changing from a parking state to a driving state, the claw device is released from the parking lock gear by an axial displacement of the movable transmission means.

[0020] According to a further development of the parking lock, the guide device comprises a plurality of guide pins or guide bolts. The guide bolts can, for example, be attached to one side of a transmission housing of the motor vehicle transmission. Preferably, the guide device comprises three guide bolts. Optionally, the plurality of guide pins can be arranged distributed around the circumference, i.e., in the circumferential direction. The guide pins can, in particular, be designed to guide the claw device and absorb the torque from the parking lock gear.

[0021] Furthermore, the movable transmission means and the claw device can be mounted in a rotationally fixed manner relative to a transmission housing of the motor vehicle transmission by means of a guide device. Alternatively or additionally, the movable transmission means can at least partially encompass the claw device in the circumferential direction. Short description of the drawings

[0022] The invention is explained below with reference to the figures of the drawings. The figures show: Fig. 1 is a perspective view of a parking lock for a motor vehicle transmission according to an embodiment of the invention; Fig. 2 a schematic side view of the Fig. 1 shown parking lock; Fig. 3 a schematic side view in partial section of the Fig. 1 shown parking lock in a driving state; Fig. 4 a schematic side view in partial section of the Fig. 1 shown parking lock in an intermediate state; Fig. 5 a schematic side view in partial section of the Fig. 1 shown parking lock in a parking state; Fig. 6 a schematic plan view of a section of a motor vehicle transmission with a parking lock according to an embodiment of the invention.

[0023] In the figures, the same reference numerals designate identical or functionally equivalent components, unless otherwise stated. The numbering of process steps is for clarity and generally does not imply a specific chronological order. In particular, several process steps can be performed simultaneously. Description of the embodiments

[0024] Further advantages, features and details of the invention will become apparent from the following description, in which various embodiments are described in detail with reference to the drawing.

[0025] Fig. 1 and Fig. 2 show a parking lock 1 for a motor vehicle transmission, wherein Fig. 1 the parking lock 1 in a perspective view and Fig. 2 shows the parking lock 1 in a schematic side view.

[0026] The parking lock 1 comprises a claw device 2, which is mounted coaxially with respect to a parking lock gear P and has four to eight locking teeth 4 on an end face 3, which are designed for positive engagement with the parking lock gear P. The claw device 2 is designed as a claw and is capable of blocking the parking lock gear.

[0027] The parking lock 1 further comprises an actuator 5 for displacing the claw device 2 so that it can be reversibly brought into engagement with the parking lock gear P by means of the four to eight locking teeth 4.

[0028] Furthermore, the parking lock 1 comprises a movable transmission means 6, which transmits the movement of the actuator 5 to the claw device 2. The movable transmission means 6 and the claw device 2 are mounted for axial displacement by means of a guide device 10. The guide device 10 here has, for example, three guide pins or guide bolts 10a, 10b, 10c. The three guide bolts are arranged distributed around the circumference and fastened on one side in a transmission housing. The three guide bolts 10a, 10b, 10c guide the claw 2 axially and absorb the torque from the parking lock gear P.

[0029] By way of example, the movable transmission means 6 here comprises a spindle 7 and a spindle nut 8. The spindle 7 is driven by the actuator 5 and extends parallel to a drive shaft A of the motor vehicle transmission. The spindle 7 is supported by two ball bearings 16. The spindle 7 contains a groove 17 on the end face of the actuator 5. This groove 17 transmits the torque from the actuator 5 to the spindle 7.

[0030] The movable transmission means 6 is designed, for example, as a shift fork to confirm the claw 2. The spindle 7 and the spindle nut 8 are integrated in the shift fork 6, as shown in particular in Fig. 1 can be seen. The shift fork 6 actuates the claw 2 and thus brings the claw 2 into position for a respective state of the parking lock 1, for example a parking state.

[0031] The shift fork 6 is optionally coupled to a locking element 9 pivotably mounted on the transmission housing, wherein the locking element 9 axially fixes the claw 2 in the parked state. The shift fork 6 is coupled to the locking element 9 by means of a hook-shaped connecting element 11 for pivoting the locking element 9. The locking element 9 is designed, in particular, as a locking lever.

[0032] As in Fig. 2, the locking lever 9 is spring-loaded and pivotally mounted and has a projection 12 as a stop for the locking lever 9 in the park state. The locking lever 9 locks the claw 2 in the engaged state "P", i.e. the park state. This locking lever 9 is mounted on a pin 18. The pin 18 is mounted in the gearbox housing at both ends. This pin 18 mounts the locking lever 9 in a rotation-free manner and absorbs the axial forces from the claw 2. The locking lever 9 is connected to the shift fork 6 by the hook-shaped connecting element 11. The hook-shaped connecting element 11 is designed here as a hook. One end of this hook 11 is mounted on the locking lever 9 in a rotation-free manner and the other end is mounted on the shift fork 6 in a likewise rotation-free and axially displaceable manner. The stop or projection 12 on this hook 11 prevents the hook 11 from falling out of the shift fork 6.By actuating the shift fork 6, the locking lever 9 opens via the hook 11 and the claw 2 is released, allowing axial movement. A spring 19 ensures that the hook 11 remains preloaded and that the locking lever 9 engages upon engagement, securing the axial position of the claw 2.

[0033] The axial movement of the shift fork 6 is limited by a retaining ring 13, which is mounted on each of the three guide pins 10a, 10b, 10c. Furthermore, the shift fork 6 has a compression spring 14, which transmits a transmission force to the claw 2. The compression spring 14 surrounds, for example, a guide pin.

[0034] In addition, the claw 2 contains a locking ring 15 as a stop for the shift fork 6, so that when changing from the parking state to a driving state, the claw 2 is released from the parking lock gear P by an axial displacement of the shift fork 6.

[0035] Fig. 3 shows a schematic side view in partial section of the Fig. 1 shown parking lock 1 in a driving state.

[0036] In the drive position (or No Park Position; position “NP”), the parking lock gear is not blocked by the locking teeth 4, so that a motor vehicle can be driven via the vehicle transmission. To get into or stay in the drive position, the actuator 5 rotates in one direction, for example to the left. The rotational movement is transmitted to the spindle 7 via the groove 17. With the help of the spindle nut 8 in the shift fork 6, the rotational movement is translated into a translational movement and the shift fork 6 is moved in the axial direction, i.e. to the right in this case. As a result, initially only the hook 11 moves to the right and actuates the locking lever or locking hook 9. The locking lever 9 tilts upwards and clears the way for the claw 2. The shift fork 6 moves further to the right and from the moment the shift fork 6 reaches the locking ring 15 on the claw 2, the claw 2 is taken along.The shift fork 6 and the claw 2 are moved to the right until the end position, i.e., the driving state, is reached and the parking lock gear P is released. The retaining ring 15 ensures that the shift fork 6 does not exceed the end position and fall out of the guide pins 10a, 10b, 10c. The "NP" position, i.e., the driving state, is reached.

[0037] Fig. 4 shows a schematic side view in partial section of the Fig. 1 shown parking lock 1 in an intermediate state.

[0038] In the intermediate state (or Tooth Tooth Position; position “TT”), the actuator 5 rotates in the other direction, i.e. to the right in the illustrated case. This causes the shift fork 6 to move axially to the left. The shift fork 6 preloads the compression spring 14 and the claw 2 can move to the left until it hits the parking lock gear P. The claw 2 is thus preloaded by the compression spring 14 and can penetrate the parking lock gear P as soon as the tooth / gap position is achieved. While the shift fork 6 has moved to the left, the hook 11 has also moved to the left and the preloaded spring 19 actuates the locking lever 9. The locking lever 9 tilts downwards until it hits the claw 2. The claw 2 can still move axially because the locking lever 9 is preloaded in this position, i.e. in the intermediate state, but is not yet engaged. The position “TT”, i.e. the intermediate state, is engaged.

[0039] Fig. 5 shows a schematic side view in partial section of the Fig. 1 shown parking lock 1 in a parking state.

[0040] In the parked state (or park position; position “P”), the parking lock gear P is blocked by the locking teeth 4, so that a motor vehicle cannot be driven via the motor vehicle transmission. In order to get into the parked state or to remain in it, the intermediate state is assumed as the starting state in this explanation. Alternatively, the same steps as above for the intermediate state can be carried out and continued as follows. The spiral spring or compression spring 14 is pre-tensioned and ready for engagement. As soon as the parking lock gear P rotates and a tooth gap between two teeth of the parking lock gear P is free, the claw 2 can move to the left and penetrate into the parking lock gear P. The locking lever 9 is also pre-tensioned and ready to engage. As soon as the claw 2 penetrates the parking lock gear P, the locking lever 9 slides over an edge of the claw 2 and engages.The claw 2 is thus axially secured and the position “P”, i.e. the parking state, is completed or reached.

[0041] Fig. 6 shows a schematic plan view of a section of a motor vehicle transmission with a parking lock 1.

[0042] In Fig. 6 clearly illustrates that the parking lock 1 according to the embodiment according to Fig. 1 and Fig. 2 can be arranged in a dead space TR of the motor vehicle transmission.

[0043] Parking lock 1 can be installed in various types of transmissions. For example, it is suitable for motor vehicles with manual transmissions, automated or automatic transmissions, or for transmissions in electric vehicles.

[0044] The parking lock 1 can have its own housing as a parking lock housing. The parking lock housing then either forms a common housing with the transmission housing, or the parking lock housing is arranged within the transmission housing. Alternatively, the parking lock 1 can be without its own housing, so that the housing for the parking lock is the transmission housing itself.

[0045] Although the present invention has been explained above using exemplary embodiments, it is not limited thereto but can be modified in a variety of ways. In particular, combinations of the above embodiments are also conceivable. QUOTES CONTAINED IN THE DESCRIPTION

[0000] This list of documents submitted by the applicant was generated automatically and is included solely for the convenience of the reader. This list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions. Cited patent literature

[0000] DE 10 2014 218 093 A1

[0004] DE 10 2020 123 613 A1

[0004]

Claims

[1] Parking lock (1) for a motor vehicle transmission with: a claw device (2) which is mounted coaxially with respect to a parking lock gear (P) and has at least one locking tooth (4) on an end face (3) which is designed for positive engagement with the parking lock gear (P); an actuator (5) for displacing the claw device (2) so that it can be reversibly brought into engagement with the parking lock gear (P) by means of the at least one locking tooth (4); and a movable transmission means (6) which transmits the movement of the actuator (5) to the claw device (2), wherein the movable transmission means (6) and the claw device (2) are mounted axially displaceably by means of a guide device (10). [2] Parking lock (1) according to claim 1, wherein the movable transmission means (6) comprises a spindle (7) and a spindle nut (8), wherein the spindle (7) is drivable by the actuator (5) and extends parallel to a drive shaft (A) of the motor vehicle transmission. [3] Parking lock (1) according to claim 1 or 2, wherein the claw device (2) has at least two locking teeth (4), preferably four to eight locking teeth (4), on the end face (3). [4] Parking lock (1) according to one of the preceding claims, wherein the movable transmission means (6) is coupled to a latching element (9) pivotally mounted on the transmission housing, wherein the latching element (9) axially fixes the claw device (2) in a parking state. [5] Parking lock (1) according to claim 4, wherein the movable transmission means (6) is coupled to the locking element (9) by means of a hook-shaped connecting element (11) for pivoting the locking element (9). [6] Parking lock (1) according to claim 4 or 5, wherein the latching element (9) is pivotally mounted in a spring-loaded manner and has a projection (12) as a stop for the latching element (9) in the parking state. [7] Parking lock (1) according to one of the preceding claims, wherein an axial movement of the movable transmission means (6) is limited by a locking ring (13) which is mounted on the guide device (10). [8] Parking lock (1) according to one of the preceding claims, wherein the movable transmission means (6) comprises a compression spring device (14) which transmits a transmission force to the claw device (2). [9] Parking lock (1) according to one of the preceding claims, wherein the claw device (2) contains a locking ring (15) as a stop for the movable transmission means (6), so that when changing from a parking state to a driving state, the claw device (2) is released from the parking lock wheel by an axial displacement of the movable transmission means (6). [10] Parking lock (1) according to one of the preceding claims, wherein the guide device (10) has a plurality of guide pins (10a, 10b, 10c).

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