Parking lock and method for assembling same

Abstract

The invention relates to a parking lock (1), comprising: a pawl (2), which in a locking position can be latched together with a parking lock wheel (3) and in an unlocking position is disengaged from the parking lock wheel (3); a carriage (5), which has a stop surface (7) and which is movable by the pawl (2) into the locking position; a spring (4) that preloads the carriage (5); a parking lock housing (25) relative to which the carriage (5) is movable; and a counterpart stop surface (8) which is arranged in a fixed position relative to the parking lock housing (25) and which, together with the stop surface (7), forms a stop (10) for the carriage (5). The stop surface (7) or the counterpart stop surface (8) is of domed design.

Description

[0001] Parking lock and method for its installation

[0002] The invention relates to a parking lock according to the preamble of claim 1.

[0003] The parking lock of an automatic transmission of a motor vehicle known from DE 101 44 063 A1 has a locking ring with locking recesses arranged on a transmission shaft. By means of a pivoting selector lever and a linkage articulated thereto, a pawl is engaged with the locking recesses when the device is in the locked state. The linkage has rollers at its end, a second roller of which guides the linkage in an L-shaped guide plate. The guide plate is fastened in the housing of the automatic transmission. The second roller rolls on the guide plate during a longitudinal movement of the linkage. The guide plate comprises a side wall and a horizontal wall. The horizontal wall of the guide plate has elongated holes. The side wall of the guide plate is a separate component and has crenellated projections on one edge.These projections are adapted in terms of their dimensions to the elongated holes of the horizontal wall and can engage in the openings of the horizontal wall by means of a press fit.

[0004] Parking locks according to DE 10 2018 221 913 A1 or DE 101 44 058 A1 are mounted on the transmission housing with a pawl and an actuating unit. The parking lock gear, located on the drivetrain, can be supported on a transmission housing via the pawl. The different mounting reference points result in tolerances that must be compensated. In particular, dimensional fluctuations occur due to manufacturing processes between the centering holes in the housing and the contact surface of the actuating unit that moves the pawl. Therefore, adjustments must always be made when installing the parking lock to ensure the exact positioning of the pawl in relation to the parking lock gear.Although it is conceivable to shift the adjustment work from the parking lock gear-pawl interface to the pawl-actuating mechanism interface of the pawl, for example an electric motor, this has the disadvantage that the parking lock with its actuators cannot be provided as a prefabricated module, which in turn increases the assembly effort.

[0005] DE 10 2018 131 263 B4 proposes a movable plate that can tilt and thus compensate for manufacturing tolerances. Due to the load introduction in the pawl contact and the load discharge at the gearbox housing-plate contact at two non-opposite contact points of the locking element, the locking element can tilt until the two contact force vectors meet again on the center axis of the locking element. It has been found that this type of tolerance compensation is not sufficient in every case. Due to the usual guidance of the locking element on a guide rod and the insufficient degree of freedom between them, the angle compensation cannot be fully implemented. Consequently, the locking element is supported on the guide rod, load is introduced, and the guide rod bends. This leads to significant limitations in the function of the parking lock.

[0006] To reduce the load on the guide or actuating rod, DE 10 2018221 913 A1 or DE 102021 116 952 A1 propose connecting the guide rod with a hinge. This reduces, but does not completely eliminate, the tension in the guide rod. However, large forces can still act on the carriage and its connected parts within the system, caused by ratcheting of the parking lock or by high accelerations that can occur when unlocking under heavy loads. These forces cause deformation in the force-transmitting parts and can damage the carriage assembly because the deformation, even if initially only elastic, can cause warping or wedging.

[0007] Finally, DE 102017 127 211 shows a parking lock with a slide. Due to the high preload, the slide can still retain a high level of kinetic energy after the locking pawl has been engaged. Upon contact with the housing, the slide can impact the housing, resulting in high levels of noise. To dampen this, it is proposed to partially convert the kinetic energy into deformation energy using a double sheet metal or to spread the momentum over time.

[0008] However, the parking locks presented here do not solve the problem that occurs when the vehicle is deflected. Parking locks are designed to lock securely below a speed limit of a few km / h, but above this speed they must perform a deflection movement to avoid overloading and thereby destroying the system. This deflection is achieved because the time available for the pawl to engage the locking teeth of the parking lock gear is no longer sufficient above the speed limit. The width of the tooth gaps on the parking lock gear takes this effect into account. To move the pawl into the locked position, a pre-tensioned compression spring moves the carriage against a ramp integrated into the pawl. If the speed of the locking gear is too high, however, so that the pawl tooth does not engage far enough into the locking gear, the entire carriage is suddenly deflected towards the non-parking position.The compression spring is unable to slow down the carriage sufficiently, so that it hits the end stop at a relatively high speed.

[0009] Object of the invention

[0010] The object of the present invention is to improve a parking lock and to avoid the disadvantages mentioned above.

[0011] The problem is solved by a parking lock with the features of claim 1.

[0012] The parking lock according to claim 1 comprises a deflection stop with a stop surface and a counter-stop surface, at least one of which is spherical. The spherical design ensures that a carriage, which rotates slightly as a result of the deflection of the pawl and thus impinges undefined upon the counter-stop surface, can be supported vertically against it, so that no torque is generated or at least the torque is reduced. Consequently, the other components of the parking lock have to absorb and transmit fewer torques.

[0013] A spherical design means that the stop surface or the counter stop surface is convex. They can, in particular, be rounded and, for example, describe a partial segment of a cylinder or a sphere.

[0014] A deflection stop is understood to be a stop provided in the event that the carriage is deflected by the parking lock gear and consequently moves backward. "Backward" is opposite to the initial actuation direction of the carriage, which is usually determined by releasing the preload of a spring. As a rule, a stop at the deflection stop only occurs after the locking pawl has deflected.

[0015] In one embodiment of the invention, both the stop surface and the counter stop surface are spherical. Both can have different curvatures. Preferably, they both have the same, constant curvature.

[0016] In an alternative design, the stop surface is crowned and the counter stop surface is flat, or vice versa. The flat surface is easier to manufacture and also provides satisfactory torque absorption.

[0017] The introduced moments can be further minimized if the center of mass of the slide, hereinafter referred to as the center of gravity, can be moved along a straight line with the deflection stop, and if the stop has a radius whose center is located on the aforementioned straight line. In this case, even when the slide is rotated, support is provided along the slide axis, so that hardly any additional deformation forces occur during the deflection. In one embodiment of the further development, the center of gravity of the slide and the center of the radius describing the stop coincide. This represents the optimum for the slide loading.

[0018] In a further embodiment, the counter-stop surface is arranged on a reinforcement plate. The reinforcement plate can form part of the parking lock housing. In one variant, the counter-stop surface can also be formed by several, for example, two, reinforcement plates. This eliminates the need for a separate component as a counter-stop surface.

[0019] In a further development, the reinforcement plate has a passage for a bolt supporting the locking pawl. The reinforcement plate thus performs multiple functions and can be supported by the bolt on a gearbox housing in the event of an impact.

[0020] This principle can be applied to an additional stop that acts in the opposite direction during locking in case of overshoots. For this purpose, the slide can have an additional stop surface, which is arranged opposite the stop surface and forms an additional stop with a further counter stop surface. In this embodiment, the additional stop surface or the additional counter stop surface are similarly crowned.

[0021] The parking lock carriage can be supported by exactly three support points within the parking lock. This provides the carriage with a statically determined guide. There is neither an overdetermination nor does the carriage guide have to be completely eliminated, which complicates the design of the parking lock.

[0022] The parking lock housing does not need to enclose the parking lock on multiple sides. This can accommodate a support element for rollers. Additionally or alternatively, it can guide the actuating rod, mount the pawl, and / or accommodate a return spring for the pawl. The pawl is a pawl that can be moved around a pivot point and has a locking tooth at the end facing away from the pivot point, by means of which the pawl can be positively locked into a tooth profile arranged on the parking lock gear. On the side radially facing away from the locking tooth on the parking lock gear, the pawl has a pawl back with a pawl profile that is acted upon by an actuating unit when the parking lock is engaged. The pawl profile can form a profile in the narrower sense, that is designed as a mountain of profiles. In one variant, the pawl profile is a flat surface with a raised portion, so that there is also a positive connection at the pawl back in the locked position.

[0023] The actuating rod transmits the externally applied force for actuating and / or releasing the parking lock to the pawl. The actuating rod preferably moves linearly; this direction of movement is generally approximately parallel to the pawl in its engaged state. This results in a particularly compact parking lock.

[0024] The parking lock has a spring-loaded carriage so that the parking lock can be automatically released in the event of an actuator malfunction. The carriage can hold one or more rollers, which roll with low friction on the pawl profile when the parking lock is engaged or disengaged. If there are multiple rollers, these rollers can be arranged so that they roll against each other during movement. For this purpose, they can be arranged radially one above the other.

[0025] The rollers are supported on the one hand on the pawl profile and on the other hand on a gearbox housing, wherein a raceway plate can be arranged between the gearbox housing and the roller as part of the gearbox housing or as part of the parking lock housing. It is preferably supported on this at all times, in the engaged state (P) and in the disengaged state (nP). In a further embodiment, it is provided that the actuating unit is supported on the support element at different positions in the engaged state (P) and in the disengaged state (nP). For this purpose, it can roll or slide on the support element during actuation, depending on the bearing. The arrangement of the support element with play ensures that the actuating unit contacts the support element in every state. In a further embodiment, the support element is spring-loaded, so that although it continues to have play with the parking lock housing oris connected to the gearbox housing, but always occupies a defined position.

[0026] The vehicle may be a motor vehicle. The vehicle may be a hybrid vehicle or an electric vehicle. The vehicle may have a drivetrain with a transmission. The transmission may be installed in an electric axle.

[0027] Further advantages and advantageous embodiments of the invention emerge from the description of the figures and the illustrations.

[0028] Description of the drawings

[0029] The invention is described below with reference to the drawings, which show in detail:

[0030] Figure 1 shows a cross-section of a first parking lock according to the invention with a spherical stop surface in the carriage,

[0031] Figure 2 shows a cross-section of a second parking lock according to the invention with a spherical counter-stop surface in the parking lock housing,

[0032] Figure 3 shows a cross-section of a third parking lock according to the state of the art, with a twisted carriage and

[0033] Figure 4 shows a cross-section of the third parking lock according to Figure 3, in which the carriage is rotated in a different direction.

[0034] Figures 1 to 4 show a parking lock unit 21, which is formed from a parking lock 1 and a parking lock gear 3. The parking lock 1 has a pawl 2, which is rotatable about a rotational axis 30 formed by a bolt 15. The bolt 15 is received in a reinforcement plate 26, which forms part of a parking lock housing 25.

[0035] When the pawl 2 is rotated, a ratchet tooth 23 formed integrally with it acts as a locking tooth, essentially moving radially relative to the main transmission shaft (not shown). The parking lock 1 is intended for installation in a vehicle transmission of a motor vehicle and locks a parking lock gear 3, which is connected in a rotationally fixed manner to the main transmission shaft. For this purpose, the parking lock gear 3 has a locking toothing 29 arranged on its outer circumference, into which the pawl tooth 23 positively locks when the parking lock 1 is in the locked position. In the unlocked position, the pawl tooth 23 and the locking toothing 29 are disengaged.

[0036] The pawl 2 is held by a return spring 28, which prevents the pawl from inadvertently locking against the parking lock gear 3 due to gravity when unloaded.

[0037] The parking lock 1 further comprises two housing walls 31, only one of which is shown. Both housing walls 31 are formed as sheet metal parts and arranged parallel to each other. They are spaced apart from each other by several, in this case two, spacer sleeves 33 and, together with a raceway element 13, form a parking lock housing 25. The spacer sleeves 33, as hollow cylinders, also allow the parking lock 1 to be attached to the transmission (not shown) by forming sleeves for screws (not shown). The parking lock 1 is thus compact and securely supported.

[0038] The parking lock has a carriage 5 preloaded by a spring 4 so that the parking lock 1 can be locked even in the event of a malfunction of an actuator (not shown), by displacing the carriage 5 so that it brings the pawl 2 into the locked position or, in the case of a tooth-on-tooth position of the pawl tooth 23 with the locking toothing 29, at least preloads it so that locking occurs with a slight movement of the parking lock gear 3. An actuating rod 6 serves as a pull rod and is linearly movable along its main direction of extension, which runs essentially tangentially to the parking lock gear 3. For this purpose, it has a flange 20 at its end, via which it is connected to the carriage 5. The spring 4 radially surrounds the actuating rod 6, which can therefore also guide it.

[0039] The carriage 5 is box-shaped with two parallel side elements 9. The side elements 9, 10 are firmly connected via end walls to form a box-shaped carriage housing. They each have a pocket 14 in the form of an elongated hole. Two rollers 11, 12 are arranged in the pockets 14 and roll against each other. The first roller 11 also rolls on the pawl 2, and the second roller 12 rolls on the track element 13, thus supporting itself on the parking lock housing 25.

[0040] In the park position, the pawl tooth 23 of the locking pawl 2 engages a gap in the parking lock gear 3. If the vehicle were to move, the parking lock gear 3 would have to rotate, which it cannot do due to its locked state. The torque generated by the parking lock gear 3 is supported by the pawl tooth 23. The force introduced into the locking pawl 2, in turn, is supported via the rollers 11, 12 in the carriage 5 on the track element 13, which is ultimately supported in the transmission housing (not shown). A torque introduced by the parking lock gear 3 is therefore supported in the transmission housing without any axial offset.

[0041] In order for the pawl 2 to move into the P position, the pre-tensioned spring 4, which is designed as a helical compression spring, moves the carriage 5 with the two rollers 11, 12 mounted therein against a ramp 27 integrated in the pawl 2. However, if the speed of the parking lock gear 3 is too high, so that the pawl tooth 23 does not engage far enough into the parking lock gear 3 and the rollers 11, 12 in the carriage have not yet reached the plateau 32 of the ramp 27, the entire carriage 5 is suddenly rejected in the non-parking direction. The spring 4 is unable to slow down the carriage 5, so that it hits the rejection stop 10 formed by the stop surface 7 and the counter-stop surface 8 at a relatively high speed. As can be seen from Figures 3 and 4, the carriage 5 can rotate slightly due to the guide length. This leads to an undefined impact at the target.In the case of Figure 3, the slide 5 strikes the counter-stop surface 8 on the side facing away from the pawl 2. In the case of Figure 4, the slide 5 is tilted in the opposite direction, so that it strikes the counter-stop surface 8 on the side facing the pawl 2. Due to the rotation, torques are introduced into the slide 5 that other components would have to absorb, but cannot withstand due to their strength.

[0042] As can be seen from Figures 1 and 2, the moment in the deflection stop 10 can be significantly reduced or even avoided. For this purpose, at least the stop surface 7 or the counter-stop surface 8 is spherical. Furthermore, the stop surface 7 and the counter-stop surface 8 are arranged exactly at the level of the slide's center of gravity 16, i.e., on the straight line that forms the presently linear direction of movement as the actuation direction 22 of the slide 5 through the center of gravity 16. The slide 5 also has a further stop surface 17 on the side opposite the stop surface 7. This can reduce the introduction of moments into the parking lock housing 25 in the event of overshoots in the opposite direction, according to the same principle.

[0043] List of reference symbols

[0044] 1 parking lock

[0045] 2 pawls

[0046] 3 parking lock gear

[0047] 4 springs

[0048] 5 sleds

[0049] 6 Operating rod

[0050] 7 Stop surface

[0051] 8 Counter stop surface

[0052] 9 Page element

[0053] 10 Deflector stop

[0054] 11 first role

[0055] 12 second roll

[0056] 13 track element

[0057] 14 bag

[0058] 15 bolts

[0059] 16 Focus

[0060] 17 additional stop surfaces

[0061] 18

[0062] 19

[0063] 20 flange

[0064] 21 Parking lock unit

[0065] 22 Actuation direction

[0066] 23 ratchet tooth

[0067] 24 Center

[0068] 25 parking lock housing

[0069] 26 Reinforcing sheet

[0070] 27 Ramp

[0071] 28 Return spring

[0072] 29 locking teeth

[0073] 30 axis of rotation

[0074] 31 Housing wall

[0075] 32 Plateau

[0076] 33 spacer sleeve

Claims

Patent claims 1 . Parking lock (1 ), comprising - a pawl (2) which can be locked in a locking position with a locking toothing (29) of a parking lock gear (3) and is disengaged from the locking toothing (29) in an unlocking position, - a carriage (5) movable from the unlocked position into an actuating direction (22), by means of which the locking pawl (2) can be moved into the locked position below a limit speed of the parking lock wheel (3) and by means of which the locking pawl (2) forces the carriage (5) to move backwards in the opposite direction to the actuating direction (22) above the limit speed, - a parking lock housing (25) relative to which the carriage (5) is movable, - a deflection stop (10) which limits the return movement of the carriage (5) and which is formed by a stop surface (7) arranged on the carriage (5) and a counter-stop surface (8) arranged in a fixed position relative to the parking lock housing (25), characterized in that the stop surface (7) or the counter-stop surface (8) is spherical.

2. Parking lock according to claim 1, characterized in that the stop surface (7) and the counter-stop surface (8) are spherical.

3. Parking lock according to claim 1 or 2, characterized in that the stop surface (7) is formed by a lateral surface segment of a cylinder with a central axis (M).

4. Parking lock according to claim 1 or 2, characterized in that the stop surface (7) is formed by a surface segment of a sphere with a center point (24).

5. Parking lock according to claim 5, characterized in that the center of gravity (16) of the carriage (5) coincides with the center point (24).

6. Parking lock (1) according to one of the preceding claims, characterized in that the center of gravity (16) of the carriage (5) and the deflection stop (10) lie on a straight line which is parallel to the actuating direction (22).

7. Parking lock (1) according to one of the preceding claims, characterized in that the counter stop surface (8) is arranged on a reinforcing plate (26).

8. Parking lock (1) according to claim 7, characterized in that the reinforcing plate has a passage for a bolt (15) supporting the locking pawl (2).

9. Parking lock (1) according to one of the preceding claims, characterized in that a spring (4) preloads the slide (5) in the unlocked position and its preload can be released by an actuator.

10. Parking lock (1) according to one of the preceding claims, characterized in that the carriage has a further stop surface (17) which is arranged opposite the stop surface (7) and forms a further stop with a further counter-stop surface (18), and that the further stop surface (17) or the further counter-stop surface (18) are spherical.

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