ELECTROMECHANICAL PARK LOCK

Abstract

The invention relates to a gearbox (40) having a park lock (42) which is integrated in a gearbox housing (60) of the gearbox (40). Said park lock comprises a transfer device (48), a detent (50), and a park lock gear (52). Outside the gearbox housing (60) there is an electromechanical actuator (44), which is centred on an interface to the transfer device (48) on the gearbox housing (48) and is sealed off from the gearbox housing (60) there.

Claims

1. A gearbox (40) comprising a parking lock (42) which is integrated in a gearbox housing (60) of the gearbox (40), a transfer device (48), a detent (50) and a parking lock gear (52), characterized in that an electromechanical actuator (44) is arranged outside the gearbox housing (60), which actuator is centered with respect to the transfer device (48) on an interface on the gearbox housing (60) and is sealed off from the gearbox housing (60) at the interface.

2. The gearbox (40) as claimed in 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. The gearbox (40) as claimed in 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.

4. The gearbox (40) as claimed in claim 2, characterized in that the intermediate piece (58) with the shaft piece (56), axial sealing ring (70) and shaft sealing ring (66) is centered in relation to a gear wheel shaft (64) of the transfer device (48) on the gearbox housing (60).

5. The gearbox (40) as claimed in claim 1, 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).

6. The gearbox (40) as claimed in claim 5, 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).

7. The gearbox (40) as claimed in claim 6, 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).

8. The gearbox (40) as claimed in claim 5, 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).

9. The gearbox (40) as claimed in claim 5, 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°.

10. A gearbox (40) comprising a parking lock (42) which is integrated in a gearbox housing (60) of the gearbox (40), a transfer device (48), a detent (50) and a parking lock gear (52), characterized in that the transfer device (48) has a deflection means (78) which is pivotally arranged on a pivot bearing (82) which simultaneously represents a bearing of the detent (50).

11. The gearbox (40) as claimed in claim 1, characterized in that the electromechanical actuator (44) is an electric motor.

12. A method for assembling the gearbox (40) as claimed in claim 1, having the following method steps: a) assembling the transfer device (48) in the oil chamber (46) of the gearbox (40), b) inserting a shaft piece (56) of the intermediate piece (58) into a gear wheel shaft (64) of the transfer device (48), c) aligning the shaft piece (56) of the intermediate piece (58) with respect to the drive shaft (54) of the transfer device (48), d) fixing the intermediate piece (58) in a sealing manner on the gearbox housing (60) in the alignment position of the intermediate piece (58) which is established according to method step c), and e) assembling the electromechanical actuator (44) outside the gearbox housing (60) in a torsion-resistant manner on the shaft piece (56), such that the intermediate piece (58) and the electromechanical actuator (44) are centered with respect to one another on the transfer device (48) assembled according to method step a).

13. The method as claimed in claim 12, characterized in that the intermediate piece (58) is fixed on the gearbox housing (60) by means of a floating bearing.

14. (canceled)

15. A vehicle comprising at least one electric drive and the gearbox (40) as claimed in claim 1.

16. A vehicle comprising at least one electric drive and the gearbox (40) as claimed in claim 10.

17. A method for assembling the gearbox (40) as claimed in claim 10, having the following method steps: a) assembling the transfer device (48) in the oil chamber (46) of the gearbox (40), b) inserting a shaft piece (56) of the intermediate piece (58) into a gear wheel shaft (64) of the transfer device (48), c) aligning the shaft piece (56) of the intermediate piece (58) with respect to the drive shaft (54) of the transfer device (48), d) fixing the intermediate piece (58) in a sealing manner on the gearbox housing (60) in the alignment position of the intermediate piece (58) which is established according to method step c), and e) assembling the electromechanical actuator (44) outside the gearbox housing (60) in a torsion-resistant manner on the shaft piece (56), such that the intermediate piece (58) and the electromechanical actuator (44) are centered with respect to one another on the transfer device (48) assembled according to method step a).

18. The method as claimed in claim 17, characterized in that the intermediate piece (58) is fixed on the gearbox housing (60) by means of a floating bearing.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0028] The invention is described in more detail below with reference to the drawing, which shows:

[0029] FIG. 1 a parking brake known from the prior art,

[0030] FIG. 2 an illustration of the parking lock proposed according to the invention, with components arranged outside the gearbox housing and with components integrated in the gearbox housing,

[0031] FIG. 3 an enlarged illustration of the intermediate piece and

[0032] FIG. 4 a plan view of a gearbox illustrated in partial section.

DETAILED DESCRIPTION

[0033] FIG. 1 shows a locking magnet 10, which is associated with a hydraulic cylinder 12. The hydraulic cylinder 12 actuates a lever and is acted upon via a hydraulic valve 14. The lever 18 is accommodated approximately centrally on a lever bearing 20 and can be pivoted about this. The lever 18 and the lever bearing 20 are deflected via the hydraulic cylinder 12 and actuate a push rod 22 in opposition to a pre-tensioning force of a spring 24. The push rod 22 is provided with a locking part 26, which in turn actuates a detent 28 which cooperates with a parking lock gear 30.

[0034] The illustration according to FIG. 2 reveals a gearbox 40 proposed according to the invention. This gearbox comprises a parking lock 42 which is actuated via a preferably electromechanical actuator 44 arranged outside the gearbox housing 60. This actuator is a simple and cost-effective electric motor, which is not oil-tight and does not have to be designed to be sealed against environmental influences of the motor chamber and which, in particular, does not have to satisfy high requirements relating to temperature resistance.

[0035] As revealed in the illustration according to FIG. 2, the gearbox housing 60 delimits an oil chamber 46. A parking lock gear 52, with which a detent 50 is associated, is located within the oil chamber. This detent is actuated via a transfer device 48 which is acted upon by the electromechanical actuator 44.

[0036] According to the illustration in FIG. 2, for example, the electromechanical actuator 44 is arranged outside the gearbox housing 60 and lies protected in a depression, which is tightly closed by a cover, and acts on a drive shaft 54. The drive shaft 54 is connected to a gear wheel shaft 64 with the interconnection of the shaft piece 56. The transfer device 48 is fixed in the oil chamber 46 of the gearbox housing 60 by fastening elements 62.

[0037] The transfer device 48 comprises a gear wheel 72, which is accommodated on the gear wheel shaft 64 and acts on a rack 74. The rack 74 is connected to a coupling member 76 designed, for example, as a coupling plate.

[0038] As is furthermore revealed in the illustration according to FIG. 2, the coupling member 76 actuates a deflection means 78, which is accommodated on a pivot bearing 82. The pivot bearing 82 is, in particular, a stay bolt which is accommodated in the gearbox housing 60. In addition to the deflection means 78, the detent 50 is also simultaneously accommodated on the pivot bearing 82, which detent is capable of moving about the pivot bearing 82 according to the double-headed arrow.

[0039] The deflection means 78 is furthermore connected to a push rod 86 on which a spring 88 is located. Located at the end of the push rod 86 is a locking element 90, which has, for example, two opposing rollers of which one abuts against a guide in the gearbox housing 60 and the other contacts the detent 50. As a result of its tooth geometry, the detent 50 is pushed out of the parking lock gear 52 when the locking element 90 is moved away, wherein this movement is promoted by a restoring spring 92 (not illustrated) which, in the disengaged state, also fixes the detent 50 in position such that it is not moved in the direction of the parking lock gear 52 as a result of the vehicle vibrating.

[0040] Upon the actuation of the electromechanical actuator 44, the drive shaft 54 thereof drives the shaft piece 56, which is accommodated in the intermediate piece 58. The rotation of the shaft piece 56 results in a rotational movement of the gear wheel shaft 64 on which the gear wheel 72 is in turn accommodated. The rotation of the gear wheel 72 results in a vertical movement of the rack 74, which movement is transferred to the deflection means 78 via the coupling member 76. The deflection means 78 transfers the substantially vertical movement of the coupling member 76 to a push rod 86 in a force direction which is offset through preferably 90° from the said vertical movement. The locking element 90, which is pre-tensioned by a spring 88, is accommodated on the push rod 86. The locking element 90 has, for example, two mutually opposing rollers, of which one contacts the detent 50 and the one opposite rolls along a guide which is constructed in the gearbox housing 60.

[0041] Both the deflection means 78 and the detent 50 are mounted on one and the same pivot bearing 82, which is designed, for example, as a stay bolt incorporated in the gearbox housing 60. The detent 50 comprises an extension which, upon actuation of the locking element 90, engages in gaps in a parking lock gear 52 and blocks this latter so that a rotation of the parking lock gear 52 is prevented.

[0042] FIG. 3 shows, in an enlarged illustration, the arrangement of the intermediate piece on the gearbox housing 60. As revealed in FIG. 3, the electromechanical actuator 44 has the drive shaft 54. One end of the shaft piece 56 is inserted in a torsion-resistant manner into this drive shaft 54, whilst its other end is inserted in a torsion-resistant manner into a correspondingly configured opening in a gear wheel shaft 64. The shaft piece 56 is guided in a guide plate 68. In turn located on the gear wheel shaft 64 is a gear wheel 72, which cooperates with a rack 74 (not illustrated in FIG. 3; c.f. the illustration according to FIG. 2 or 4).

[0043] From the enlarged illustration according to FIG. 3, it is furthermore revealed that the transfer device 48 is fastened to the base of the oil chamber 46 of the gearbox housing 60 by fastening elements 62 designed here as screws, for example.

[0044] The intermediate piece 58, which accommodates the shaft piece 56, moreover comprises an axial sealing ring 70 incorporated in a recess and a shaft sealing ring 66. The shaft sealing ring 66 is positioned against the upper surface of the shaft piece 56, whilst, during the assembly of the intermediate piece 58, this latter is fastened to the gearbox housing 60 by tightening the fastening elements 62 after it has been aligned in relation to the position of the gear wheel shaft 64. Since the axial sealing ring 70 is compressed, the intermediate piece 58, after assembly, is sealed off from the gearbox housing 60, in particular the internal oil chamber 46.

[0045] During the assembly of the gearbox proposed according to the invention, the transfer device 48 is firstly fastened to the base of the oil chamber 46 by the fastening elements 62. The intermediate piece 58, or the shaft piece 56 accommodated therein, is then aligned and centered in the gear wheel shaft 64 of the transfer device 48 from the outside. In this aligned position, the intermediate piece 58 is fixed on the gearbox housing 60 in a sealing manner, which takes place by tightening the fastening elements 62 designed here as screws. The electromechanical actuator 44 is then pushed onto the shaft piece 56 in a torsion-resistant manner, for example by means of a Torx connection, and fixed in relation to the gearbox housing 60 by fastening elements 62. Therefore, both the intermediate piece 58 and the electromechanical actuator 44 are orientated with respect to the transfer device 48, which is firstly assembled within the oil chamber 46 in the gearbox housing 60 of the gearbox 40, and are ideally centered with respect to one another.

[0046] As is further revealed in FIG. 3, both the shaft sealing ring 66 and the axial sealing ring 70 are located within the intermediate piece 58. The bearing point and the sealing function are accordingly aligned centrically with respect to the shaft piece 56 and therefore ensure an optimum sealing function. The positional tolerances between the intermediate piece 58 on the one hand and the fastening elements 62 is compensated by play between them. At the same time, the axial sealing ring 70 is pressed against the gearbox housing 60 in a sealing manner by the fastening elements 62.

[0047] As revealed in the illustration according to FIG. 4, the gear wheel shaft 64 is connected in a torsion-resistant manner to the gear wheel 72. The gear wheel 72 is driven by the electromechanical actuator 44 (c.f. the illustration according to FIG. 3) via the drive shaft 54 and the shaft piece 56. The rack 74 converts the rotational movement of the gear wheel 72 into a linear movement 80 and transfers this to the deflection means 78 via the coupling member 76. As per the solution proposed according to the invention, this deflection means is mounted on the pivot bearing 82, which is designed as a stay bolt and arranged in the gearbox housing 60. The pivot bearing 82 is simultaneously also the bearing of the detent 50. A very compact construction is thus enabled; furthermore, adaptation to extremely confined surroundings is possible. The deflection means 78 transfers its movement to the push rod 86 and this, in turn, to the spring 88 which is arranged on the push rod 86 and, from there, to the locking element 90. The locking element 90 is of a type which comprises two mutually opposing rollers, for example, of which one rolls along a guide within the gearbox housing 60 and the other actuates the detent 50.

[0048] As a result of a movement of the locking element 90 to the right, the detent 50 is pressed upwards and engages in a gap at the periphery of the parking lock gear 52. Upon the retraction of the locking element 90 to the left, the detent 50 is freed and is pressed back downwards by a restoring spring 92 (not illustrated), i.e. it moves out of engagement with the parking lock gear 52 so that this is freed again in the direction of rotation.

[0049] The invention is not restricted to the exemplary embodiments described here and the aspects highlighted therein. Instead, a plurality of modifications which lie within the capabilities of the person skilled in the art are possible within the scope specified by the claims.