ELECTROMECHANICAL PARKING LOCK

Description

Technical field

[0001] The invention relates to an electromechanically operated parking lock which is characterized by a particularly compact design. State of the art

[0002] DE 10 2011 080 972 A1 relates to a locking device. The locking device serves to lock an electric drive, which is an electric vehicle drive. The locking device comprises a rotatably arranged wheel, which has first positive locking elements, and a detent element, which has a second positive locking element. In a locked state, this second element engages positively with at least one of the first positive locking elements, so that the wheel is blocked, and in an unlocked state, it is disengaged from the wheel. The locking device is designed here as a separate unit, which is housed in its own casing.

[0003] DE 10 2011 086 547 A1 relates to a parking lock. The parking lock has a pawl that pivots about a rotary axis and has a toothed prong for engaging a locking tooth. Furthermore, an actuating unit mechanically coupled to the pawl is provided, by which the pawl tooth can be reversibly engaged with the locking tooth and is actuated by an actuator. The gearbox has a gearbox housing with an opening into which the parking lock, manufactured separately from the gearbox housing, is inserted as a unit in such a way that it at least partially closes the opening as part of the gearbox housing.

[0004] DE 10 2012 210 571 A1 relates to a device for actuating a locking mechanism. The device comprises a piston unit arranged to be axially displaceable, and a detent device that automatically activates in an axial position of the piston unit equivalent to an open state of the locking mechanism. This detent device serves to hold the piston unit in the axial position equivalent to the open state of the locking mechanism. Furthermore, an actuating device is provided for actuating a release element, which serves to deactivate the detent device. The detent device is designed to automatically activate the piston unit in an axial position equivalent to a closed state of the locking mechanism.To release a movement of the piston unit from the axial position equivalent to the closed state of the locking mechanism in the direction of the open state of the locking mechanism, it can be deactivated in an equivalent axial position.

[0005] DE 10 2012 004 395 A1 relates to a parking lock assembly, a transmission, and a motor vehicle. A parking lock gear is provided, which is non-rotatably coupled to a transmission shaft. Furthermore, a pawl is provided, pivotally mounted on a transmission housing parallel to the plane of the parking lock gear and carrying a locking hook. This pawl can pivot between a first position, in which the locking hook is positioned radially outside the teeth of the parking lock gear, and a second position, in which the locking hook engages between two teeth of the parking lock gear. A lever assembly, articulated parallel to the plane of the parking lock gear, can be moved from the first to the second pivot position by means of its pawl.The pawl is articulated to the free end of the coupling leg of a toggle lever, the main leg of which is articulated at a radial distance from the parking lock gear on the gearbox housing such that a transition of the toggle lever from an angled toggle lever position to an extended toggle lever position causes the pawl to move from the first to the second pivot position.

[0006] US 2011 / 290615 A1 discloses a transmission with a parking lock integrated into a transmission housing part of the transmission, comprising a transmission device, a pawl and a parking lock wheel, wherein an electromechanical actuator is arranged outside the transmission housing part, centered at an interface on the transmission housing to the transmission device.

[0007] From EP 3 333 463 A1, an electric parking lock actuator for actuating a parking lock in a motor vehicle is known, wherein the parking lock comprises a transmission device, a pawl and a parking lock wheel, and wherein the electric parking lock actuator is arranged outside a gearbox housing of the transmission device.

[0008] Parking brakes are generally mechanical devices that prevent a parked vehicle from rolling away by mechanically blocking a transmission shaft. This blocking is achieved through a positive engagement between a parking brake gear and a pawl. The parking brake gear is rotationally fixed to a transmission shaft, which is directly connected to at least one of the vehicle's drive axles via several gears. The mechanical mechanism of a parking brake ensures that the pawl is pressed into a gap in the parking brake gear and held there, for example, against the force generated by parking the vehicle, such as on a slope. Description of the invention

[0009] According to the invention, a transmission is proposed with a parking lock integrated into a transmission housing. The parking lock comprises a transmission device, a pawl, and a parking lock wheel. An electromechanical actuator is arranged outside the transmission housing. This actuator is centered at an interface on the transmission housing with respect to the transmission device and sealed against the transmission housing at that interface. The pawl of the parking lock and a deflection mechanism, which transmits the force of the actuator to a locking element associated with the pawl, are mounted at the same bearing point, even though the force of the actuator and the actuating force of the locking element are directed in opposite directions. The bearing point for the deflection mechanism and the pawl can, in particular, be a stud bolt formed in the transmission housing.The actuator's force is transmitted to the deflection mechanism via a linear movement of a rack. This deflection mechanism then transmits an actuating force to the locking element in a direction different from the direction of the actuator's force. The transmission device, which transmits the force of the electromechanical actuator located outside the gearbox housing, comprises a gear and a rack. The rack actuates the deflection mechanism via a coupling element, such as a coupling plate.

[0010] The advantage of the solution proposed according to the invention is that an interface on the gearbox housing to the transmission device is designed as an intermediate piece which has sealing elements on one side and a shaft piece on the other, such that after the device has been mounted in the gearbox housing, the intermediate piece which receives a shaft piece and the electromechanical actuator can be ideally centered relative to each other relative to the first mounted mechanical device.

[0011] In a further development of the solution proposed according to the invention, the intermediate piece is sealed against the gearbox housing and accommodates a drive shaft of the electromechanical actuator.

[0012] Advantageously, the intermediate piece comprises a shaft seal and an axial sealing ring, both of which are embedded in the intermediate piece and bear against a shaft section or the gearbox housing. Advantageously, the sealing function is implemented in the intermediate piece assembly with respect to both the gearbox housing and the rotating shaft section.

[0013] The intermediate piece advantageously incorporates the shaft piece, the shaft seal ring and the axial seal, thus providing a simple mounting option that compensates for tolerances, particularly when fixed to the gearbox housing in a floating bearing arrangement.

[0014] Advantageously, the deflection transfers the force of the actuator, rotated by 90°, to a push rod on which the locking element that actuates the latch is mounted.

[0015] In particular, the electromechanical actuator mounted outside the gearbox housing is a simple and cost-effective electric motor.

[0016] Finally, the invention relates to the use of such a transmission with a parking lock integrated in a transmission housing of the transmission in an electric vehicle having at least one electric drive. Advantages of the invention

[0017] The solution proposed according to the invention advantageously allows the use of a reduced number of parts for implementing the parking lock within a gearbox. For example, if a pivot bearing is formed by a stud bolt in the gearbox housing, this bearing can simultaneously accommodate the pawl associated with the parking lock wheel and, on the other hand, a deflection lever of the deflection mechanism. This results in significantly less effort during assembly. Furthermore, simpler tolerances prevail, since only one stud bolt needs to be inserted into both parts when mounting the gearbox cover onto the gearbox housing, rather than several, as is necessary with separate bearings for the pawl and the deflection mechanism. Moreover, the use of a compact deflection mechanism allows for the use of limited installation space within a gearbox housing.Furthermore, the solution proposed according to the invention makes it possible to achieve a particularly compact design for a parking lock function.

[0018] A further advantage is that the electromechanical actuator, which is located outside the oil chamber of the gearbox housing, can be a simple, cost-effective electric motor, optionally including integrated electronics. Because it is located outside the oil chamber, the electric motor does not need to be oil-tight; furthermore, no special temperature resistance requirements apply, as it is not installed inside the gearbox housing. Instead, the externally mounted electromechanical actuator can be designed as a leaking actuator and, for example, housed within a recess sealed with a cover.The compensation of positional tolerances between the parking lock components inside the oil chamber and the electromechanical actuator mounted outside the gearbox housing can be compensated, for example, by the drive shaft of the electromechanical actuator being connected to the transmission device located inside the gearbox housing, i.e., in the oil chamber, in order to transmit the torque of the actuator.

[0019] To achieve a robust seal between the components of the parking lock proposed according to the invention, the sealing components are inserted into an intermediate piece. This intermediate piece comprises a shaft section and is oriented and aligned during assembly on the transmission device mounted in the gearbox housing. This advantageously ensures that the seals are ideally centered. The intermediate piece can then be fixed to the gearbox housing via an axial seal, for example, by means of a floating bearing. This allows for a robust seal with optimal sealing function, as well as simpler assembly, since tolerances are compensated for.

[0020] Positioning the actuator outside the oil chamber allows for easy and safe replacement in case of repair. Opening the gearbox, draining the oil, and refilling it is no longer necessary.

[0021] By positioning the actuator within a recess in the gearbox housing, in conjunction with a tightly sealing, robust cover, the actuator and its electronic components are housed in a protected compartment. This provides optimal protection against environmental influences such as splashing water, driving through puddles, driving through flooded roads (customer requirement: immersion-proof), cleaning with a high-pressure cleaner, and mechanical stresses such as those caused by a vehicle bottoming out on uneven surfaces or by stone chips. A waterproof electromechanical actuator bolted externally to the gearbox housing could be damaged, torn off, or severely damaged by such mechanical stresses, especially in the case of an SUV.Positioning the transmission device in the oil chamber via the system of studs and bores (fit) on the gearbox housing results in a cost-effective and highly precise position. A bore with a fit and a stud as a standard part can be manufactured with minimal effort in the micrometer range. Brief description of the drawing

[0022] The invention is described in more detail below with reference to the drawing.

[0023] It shows: Figure 1 shows a parking brake known from the prior art, Figure 2 shows a representation of the parking lock proposed according to the invention with components arranged outside the gearbox housing as well as with components integrated into the gearbox housing, Figure 3 shows an enlarged representation of the intermediate piece and Figure 4 shows a partially cutaway top view of a gearbox.

[0024] Figure 1Figure 1 shows a locking magnet 10 associated with a hydraulic cylinder 12. The hydraulic cylinder 12 actuates a lever and is actuated via a hydraulic valve 14. The lever 18 is mounted approximately centrally on a lever bearing 20 and is rotatable about it. The hydraulic cylinder 12 deflects the lever 18 and the lever bearing 20, actuating a push rod 22 against a spring preload 24. The push rod 22 is equipped with a locking element 26, which in turn actuates a pawl 28 that interacts with a parking lock wheel 30. Design variants

[0025] According to the representation Figure 2A transmission 40 proposed according to the invention can be seen. This includes a parking lock 42, which is actuated by an actuator 44, preferably electromechanical, arranged outside a transmission housing 60. This actuator is a simple and cost-effective electric motor, which is not oil-tight and not sealed against environmental influences of the engine compartment, and which in particular does not have to meet any increased requirements regarding temperature resistance.

[0026] As can be seen from the representation according to Figure 2 As can be seen, the gearbox housing 60 defines an oil chamber 46. Inside the oil chamber is a parking lock wheel 52, to which a pawl 50 is assigned. This is actuated via a transmission device 48 actuated by the electromechanical actuator 44.

[0027] The electromechanical actuator 44 is, for example, as shown in Figure 2The transmission device 48 is arranged outside the gearbox housing 60 and is protected in a recess that is tightly sealed with a cover. It acts on a drive shaft 54. The drive shaft 54 ​​is connected to a gear shaft 64 via a shaft section 56. The transmission device 48 is fixed in the oil chamber 46 of the gearbox housing 60 by fastening elements 62.

[0028] The transmission device 48 comprises a gear 72 mounted on the gear shaft 64, which acts on a rack 74. The rack 74 is connected to a coupling element 76, for example designed as a coupling plate.

[0029] As shown in the illustration Figure 2As can be further seen, the coupling element 76 actuates a deflection 78, which is mounted on a pivot bearing 82. The pivot bearing 82 is, in particular, a stud bolt that is mounted in the gearbox housing 60. In addition to the deflection 78, the pawl 50 is also mounted on the pivot bearing 82, which is able to move around the pivot bearing 82 in the direction of the double arrow.

[0030] Furthermore, the deflection 78 is connected to a push rod 86, on which a spring 88 is located. At the end of the push rod 86 is a locking element 90, which, for example, has two opposing rollers, one of which rests against a guide in the gearbox housing 60 and the other of which contacts the pawl 50. The pawl 50 is forced out of the parking lock wheel 52 by its tooth geometry when the locking element 90 is moved away. This movement is assisted by a return spring 92 (not shown), which also fixes the pawl 50 in its position in the extended state so that it is not moved towards the parking lock wheel 52 by vibrations of the vehicle.

[0031] When the electromechanical actuator 44 is actuated, its drive shaft 54 ​​drives the shaft section 56, which is received in the intermediate piece 58. The rotation of the shaft section 56 causes a rotary movement of the gear shaft 64, on which the gear 72 is received. The rotation of the gear 72 results in a vertical movement of the rack 74, which is transmitted via the coupling element 76 to the deflection 78. The deflection 78 transmits the essentially vertical movement of the coupling element 76 in a direction preferably offset by 90° to a push rod 86. The locking element 90, which is preloaded by a spring 88, is received on the push rod 86. The locking element 90 has, for example, two opposing rollers, one of which contacts the pawl 50 and the other of which rolls on a guide provided in the gearbox housing 60.

[0032] Both the deflection 78 and the pawl 50 are mounted on the same pivot bearing 82, which is designed, for example, as a stud bolt embedded in the gearbox housing 60. The pawl 50 comprises a projection which, when the locking element 90 is actuated, engages in gaps of a parking lock wheel 52 and blocks it, thus preventing rotation of the parking lock wheel 52.

[0033] Figure 3 Figure 60 shows an enlarged view of the arrangement of the intermediate piece on the gearbox housing. As shown in Figure 60. Figure 3 As can be seen, the electromechanical actuator 44 has the drive shaft 54. One end of the shaft section 56 is inserted into this shaft in a rotationally fixed manner, while its other end is inserted into a correspondingly configured opening of a gear shaft 64 in a rotationally fixed manner. The shaft section 56 is guided in a guide plate 68. On the gear shaft 64, in turn, is a gear 72, which is connected to a Figure 3The rack 74, not shown, interacts with the illustration according to the Figure 2 or 4 .

[0034] From the enlarged representation according to Figure 3 It follows further that the transmission device 48 is fastened to the bottom of the oil chamber 46 of the gearbox housing 60 by means of fastening elements 62, which here are designed, for example, as screws.

[0035] The intermediate piece 58, which accommodates the shaft piece 56, also includes an axial sealing ring 70 recessed in a groove and a shaft seal 66. The shaft seal 66 is positioned against the top of the shaft piece 56, while during assembly, the intermediate piece 58, after being aligned with the position of the gear shaft 64, is fastened to the gearbox housing 60 by tightening the fastening elements 62. Since the axial sealing ring 70 is compressed, the intermediate piece 58 is sealed against the gearbox housing 60, and in particular against the internal oil chamber 46, after assembly.

[0036] In assembling the transmission device proposed according to the invention, the transmission device 48 is first attached to the bottom of the oil chamber 46 using the fastening elements 62. Then, the intermediate piece 58, or the shaft section 56 received therein, is aligned and centered from the outside in the gear shaft 64 of the transmission device 48. The intermediate piece 58 is then sealed against the transmission housing 60 in this aligned position by tightening the fastening elements 62 – in this case, designed as screws. Finally, the electromechanical actuator 44 is inserted onto the shaft section 56 in a rotationally fixed manner, for example, by means of a Torx connection, and secured to the transmission housing 60 with fastening elements 62.Thus, both the intermediate piece 58 and the electromechanical actuator 44 are oriented towards the transmission device 48, which is first mounted inside the oil chamber 46 in the gearbox housing 60 of the gearbox 40, and are ideally centered relative to each other.

[0037] As from Figure 3 As further shown, the intermediate piece 58 contains both the shaft seal 66 and the axial seal 70. The bearing point and the sealing function are therefore aligned concentrically with the shaft piece 56, thus ensuring optimal sealing. Positional tolerances between the intermediate piece 58 and the fastening elements 62 are compensated for by play between them. Simultaneously, the axial seal 70 is pressed tightly against the gearbox housing 60 by the fastening elements 62.

[0038] As can be seen from the representation according to Figure 4As can be seen, the gear shaft 64 is rotationally fixed to the gear 72. The gear 72 is actuated by the electromechanical actuator 44, see illustration according to Figure 3The drive shaft 54 ​​and the shaft section 56 are driven. The rack 74 converts the rotary motion of the gear 72 into a linear motion 80 and transmits this motion via the coupling element 76 to the deflection 78. According to the invention, this deflection 78 is mounted on the pivot bearing 82, which is designed as a stud bolt and is located in the gearbox housing 60. The pivot bearing 82 also serves as the bearing for the pawl 50. This allows for a very compact design and enables adaptation to extremely confined spaces. The deflection 78 transmits its motion to the push rod 86, which in turn transmits it to the spring 88 located on the push rod 86, and from there to the locking element 90. The locking element 90 comprises, for example, two opposing rollers, one of which rolls along a guide inside the gearbox housing 60, while the other actuates the pawl 50.

[0039] By moving the locking element 90 to the right, the pawl 50 is pushed upwards and engages in a gap on the circumference of the parking lock wheel 52. When the locking element 90 is moved back to the left, the pawl 50 is released and is pushed downwards again by a return spring 92 (not shown), i.e., it disengages from the parking lock wheel 52, so that the latter is free to rotate.

[0040] The invention is not limited to the embodiments described here and the aspects highlighted therein. Rather, within the scope specified by the claims, a multitude of modifications are possible that fall within the bounds of what is considered skilled in the art.

Claims

1. Gearbox (40) having a parking lock (42) which is integrated in a gearbox housing (60) of the gearbox (40) and comprises a transfer device (48), a detent (50) and a parking lock gear (52), wherein an electromechanical actuator (44) is arranged outside the gearbox housing (60), which actuator is centred with respect to the transfer device (48) on an interface on the gearbox housing (60) and is sealed off from the gearbox housing (60) there, characterized in that the detent (50) of the parking lock (42) and a deflection means (78), which transfers the force of the electromechanical actuator (44) to a locking element (90) associated with the detent (50), are mounted on one and the same pivot bearing (82) with mutually deviating force directions of the force of the actuator (44) and the actuating force of the locking element (90).

2. Gearbox (40) according to Claim 1, characterized in that the interface is formed as an intermediate piece (58) which is sealed off from the gearbox housing (60) and accommodates a drive shaft (54) of the electromechanical actuator (44).

3. Gearbox (40) according to Claim 2, characterized in that the intermediate piece (58) has a shaft sealing ring (66) and an axial sealing ring (70), which are both incorporated in the intermediate piece (58) and are positioned against a shaft piece (56) and the gearbox housing (60) respectively, wherein one end of the shaft piece (56) is inserted in a torsion-resistant manner into the drive shaft (54) and the other end of the shaft piece (56) is inserted into a correspondingly configured opening in a gear wheel shaft (64), wherein the shaft piece (56) is guided in a guide plate (68) of the intermediate piece (58).

4. Gearbox (40) according to Claim 3, characterized in that the intermediate piece (58) with the shaft piece (56), axial sealing ring (70) and shaft sealing ring (66) is centred in relation to the gear wheel shaft (64) of the transfer device (48) on the gearbox housing (60).

5. Gearbox (40) according to Claim 1, characterized in that the force of the electromechanical actuator (44) is transferred to the deflection means (78) via a linear movement (80) of a rack (74) and this deflection means transfers an actuating force to the locking element (90) in a direction which differs from the force direction of the force of the actuator (44).

6. Gearbox (40) according to Claim 5, characterized in that the force direction of the force of the electromechanical actuator (44) is perpendicular to the actuating force of the clamping element (90).

7. Gearbox (40) according to Claim 1, characterized in that the transfer device (48) comprises a gear wheel (72) and a rack (74) which actuate the deflection means (78) via a coupling member (76).

8. Gearbox (40) according to Claim 1, characterized in that the deflection means (78) transfers the force of the electromechanical actuator (44) to a push rod (86), on which the locking element (90) actuating the detent (50) is accommodated, such that the said force is offset through 90°.

9. Gearbox (40) according to Claim 1, characterized in that the electromechanical actuator (44) is an electric motor.

10. Use of the gearbox (40) with a parking lock (42) integrated in a gearbox housing (60) of the gearbox (40) according to one of Claims 1 to 9 in a vehicle having at least one electric drive.