Actuator for parking lock system of vehicle gearbox

Abstract

The present invention relates to an actuator (1) for a parking lock system of a vehicle gearbox, the actuator (1) comprising an intermediate support member (10) to which are attached an electric motor (20) and a gear drivetrain (60) kinematically connected to the electric motor (20), the actuator (1) further comprising a torque output element (70), and a housing (30) engaged with the gear power transmission system (60) and rotationally movable between a locked position and an unlocked position, the intermediate support member (10) and the torque output element (70) being disposed in the housing (30), the torque output element (70) being guided in rotation by the housing (30).

Description

Technical Field

[0001] The invention relates to an actuator for a parking lock system of a vehicle gearbox, in particular a motor vehicle equipped with an automatic gearbox, such as a hybrid vehicle. The invention is also applicable to a parking lock system of a reducer associated with an electric vehicle motor. A gearbox or reducer is generally referred to as a transmission gearbox. The locking system is better known as a parking lock or parking lock. Background Art

[0002] This actuator allows the transmission gearbox to be immobilized when the vehicle is parked by means of a lever engaging the gearbox teeth set.

[0003] Actuators of this type are known and are typically designed with a worm and worm gear system for transmitting the rotational motion of the electric motor to a torque output element of the actuator.

[0004] The disadvantage of document US 2019136974 A1 is that the same reference frame is not used for the electric motor 20 and the gear 31, since the motor is supported by the housing 10 of the actuator and the gear is guided in rotation by the intermediate plate 50. This change in the reference frame may lead to premature wear of the worm and worm gear transmission system.

[0005] A disadvantage of document DE 10 2019 100 300 A1 is that the housing is not taken into account when calculating the tolerances, which can lead to incorrect positioning of the gearbox relative to the torque output element 2 when mounted on the transmission gearbox.

[0006] In order to minimize wear in worm and worm gear transmissions, the center distance between the worm and the worm wheel must be of high precision. To achieve this, the electric motor and its worm need to be positioned very accurately relative to the gear. It also requires that the electric motor be positioned and held in place very accurately in the axial direction, i.e. along the axis through its output shaft.

[0007] Another related constraint requires good precision between the torque output element and the transmission gearbox on which the actuator is mounted in order to meet the tolerances required by the transmission gearbox manufacturer. To achieve this, the torque output element must be very accurately positioned relative to the housing of the actuator, which is itself mounted on the gearbox.

[0008] In short, the worm and the worm wheel must have the same reference system, and the torque output element and the housing must also have the same reference system. Summary of the invention

[0009] Therefore, the present invention proposes an actuator for a parking lock system of a vehicle transmission gearbox, the actuator comprising an intermediate support member, an electric motor and a gear power transmission system kinematically connected to the electric motor being attached to the intermediate support member, the actuator also comprising a torque output element which is meshed with the gear power transmission system and can be rotatably moved between a locked position and an unlocked position, the intermediate support member and the torque output element being accommodated in a housing, and the torque output element being guided in rotation by the housing.

[0010] Thus, this arrangement allows the electric motor and the geared driveline to have the same reference frame, ie the intermediate support member, just as the torque output element and the housing have the same reference frame, ie the housing.

[0011] Therefore, the electric motor is self-supported by the intermediate support member. In other words, the electric motor is supported only by the intermediate support member.

[0012] An intermediate support member refers to an element of the actuator that is distinct from the housing and the cover, the support member being called intermediate because it is interposed between the housing and the cover.

[0013] The torque output element can be guided for rotation directly by the housing or indirectly by a bearing.

[0014] Another advantage of this architecture is the simplified assembly. Specifically, the intermediate support member, the electric motor and the gear drivetrain form a subassembly that can be easily integrated into the housing, thereby avoiding the handling of components on the assembly line.

[0015] According to the present invention, the gear power transmission system is a worm and worm wheel system. The worm is on the output shaft of the electric motor. The gear system can be a single-stage or double-stage system.

[0016] According to one feature of the invention, the end of the output shaft of the electric motor is guided in rotation by the intermediate support member. In other words, the intermediate support member forms a guide bearing to guide the end of the output shaft of the electric motor. Thus, the intermediate support member prevents the motor output shaft from bending due to the forces associated with the gear driveline.

[0017] Advantageously, the electric motor comprises a front face mounted in an opening of the intermediate support member and a rear face held on the intermediate support member by a compression plate attached to the intermediate support member. Advantageously, the compression plate is made of metal. The compression plate is preferably U-shaped. The compression plate allows the electric motor to be held axially against the intermediate support member. The compression plate can also absorb significant shocks and loads from the locking system, in particular by a ratcheting effect.

[0018] According to the invention, the electric motor is fixed relative to the intermediate support member to prevent rotation by means of lugs extending from the intermediate support member and cooperating with the cutouts of the electric motor.

[0019] According to an additional characteristic of the invention, the gear system is mounted so as to be rotatable on a shaft mounted on the one hand in the intermediate support member and on the other hand in the housing.

[0020] According to the invention, the torque output element comprises a sector gear meshing with the gear driveline.

[0021] According to the invention, the gear system is a two-stage system, the first stage of the gear meshing with the worm of the output shaft of the electric motor and the second stage of the gear meshing with the sector gear of the torque output element.

[0022] According to the invention, the intermediate support member has a first face facing the housing, on which the gear powertrain is mounted, and a second face facing the electronic board.

[0023] According to another feature of the invention, the torque output element passes through the intermediate support member and has a magnetic target facing the sensor mounted on the electronic board at its end opposite to the torque output. More specifically, the intermediate support member has an opening through which the torque output element can pass from its first face to its second face. The intermediate support member does not contribute to guiding the rotation of the torque output element; there is a radial gap between the intermediate support member and the torque output element. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] Further features and advantages of the present invention will become apparent from the following study of the detailed exemplary embodiments with reference to the accompanying drawings:

[0025] Figure 1 depicts an exploded perspective view of an actuator according to the present invention;

[0026] Figure 2 Depicted Figure 1 A top perspective view of the actuator, without showing the cover;

[0027] Figure 3 Depicted Figure 1 A bottom perspective view of the actuator, without showing the housing;

[0028] Figure 4 Depicted Figure 2 AA cross-sectional view of the actuator. DETAILED DESCRIPTION

[0029] It should be noted that the accompanying drawings disclose the invention in sufficient detail for its implementation, which drawings help to better define the invention as required. However, the invention should not be limited to the embodiments disclosed in the specification.

[0030] Reference Figures 1 to 4, the actuator 1 mainly comprises a housing 30, an electric drive motor 20, a gear power transmission system 60, an intermediate support member 10, a torque output element 70, an electronic board 50 and a cover 40. The gear power transmission system 60 reduces the speed of the electric motor 20 and increases its torque. There may be a kinematic gear set between the electric motor 20 and the torque output element 70. Once the housing 30 and the cover 40 are assembled to each other, an internal volume is formed, in which the electric motor 20, the gear power transmission system 60, the intermediate support member 10, the torque output element 70 and the electronic board 50 are accommodated. The housing 30 and the cover 40 can be assembled to each other using any type of fluid-tight fixing (such as screw fastening, adhesive bonding or laser or ultrasonic welding). The housing 30 and the cover 40 are made of plastic, in particular glass fiber reinforced PBT. In order to automatically adjust the pressure inside the actuator 1, a semipermeable membrane, i.e. a membrane that is permeable to gas but impermeable to liquid, is accommodated in the housing 30 or the element 40.

[0031] The housing can be attached to the transmission gearbox by means of attachment means passing through the housing opening 36. Thus, the housing 30 is precisely positioned relative to the transmission gearbox.

[0032] The torque output element 70 is manufactured in the form of a shaft, one end of which is in the form of a star-shaped female connector 73, into which an actuating rod (not shown) of a locking system can engage in order to lock or unlock the tooth set of a transmission gearbox (not shown) by means of an actuating rod or a latch (not shown). Alternatively, the torque output element 70 can be produced in the form of a male connector. The torque output element 70 comprises a sector gear 71 meshing with the gear driveline 60.

[0033] The housing 30 comprises an opening 32 in the form of a guide cylinder into which the torque output element 70 is mounted. Due to the precise tolerances between the opening 32 and the torque output element 70, a precise rotational guidance allows the torque output element 70 to move between a locked position and an unlocked position. A sealing device 33, such as a lip seal in this case, is located concentrically with the opening 32 to ensure that external contaminants cannot enter the actuator 1. Similarly, a sealing device 34, such as an O-ring in this case, is provided between the housing 30 and the transmission gearbox.

[0034] The intermediate support member 10 supports the electric motor 20 and the gear powertrain 60 to ensure precise tolerances of the mutual assembly of these two elements. Thus, the intermediate support member 10 guides the rotation of the gear powertrain 60. The gear powertrain 60 is kinematically connected to the electric motor 20 and the torque output element 70. The intermediate support member 10, the electric motor 20 and the gear powertrain 60 form a subassembly that can be easily integrated into the housing 30.

[0035] The gear power transmission system 60 is a system of worm 21 and worm wheel 61. The worm 21 is on the output shaft of the electric motor 20. The end of the output shaft of the electric motor 20 is guided in rotation by a bearing 13 formed as an integral part of the intermediate support member 10.

[0036] The electric motor 20 comprises a front face 20a and a rear face 20b. The front face 20a and the rear face each comprise a protrusion corresponding to a shape complementary to the shape of a rolling bearing inside the electric motor. The front face 20a is mounted in the opening 11 of the intermediate support member 10, and the rear face 20b is held on the intermediate support member 10 by a compression plate 23 attached to the intermediate support member 10. The compression plate 23 is a metal strip having elasticity. The rear face 20b of the electric motor is accommodated in the opening 24 of the compression plate 23 by having a complementary shape. The compression plate 23 is attached to the intermediate support member 10 by an attachment device, in particular two screws, which are respectively located on each side of the front face 20a of the electric motor 20. The compression plate 23 can optionally be fixed to the housing 30 by a tab and an attachment device, in particular a screw, located near the rear face 20b of the electric motor. The compression plate also comprises two wings 25 pressed against the rear face 20b of the electric motor 20. The two wings 25 are located on the periphery of the opening 24 and are diametrically opposed.

[0037] The electric motor 20 is secured against rotation relative to the intermediate support member 10 by means of lugs 12 which project from the intermediate support member 10 and cooperate with cutouts 22 of the electric motor 20. The intermediate support member 10 has, at its front face 20a, a shape complementary to the outer shell of the electric motor 20, for example in this case in the form of two half shells formed as an integral part of the intermediate support member 10.

[0038] The gear 61 of the gear power transmission system 60 is mounted to be rotatable on the shaft 31, which is mainly mounted in the intermediate support member 10, but also in the housing 30. For this purpose, the intermediate support member 10 includes an attachment device for the shaft 31 in the form of a barrel 14, and the housing 30 also includes a device for guiding the shaft 31 in the form of a barrel 35. The shaft 31 is mounted in the barrel 14 of the intermediate support member with a tight fit or an interference fit, and the shaft 31 is mounted in the barrel 35 of the housing with a sliding fit. The gear 61 is a two-stage wheel, the first stage 62 of the gear 61 meshes with the worm 21 of the output shaft of the electric motor 20, and the second stage 63 of the gear 61 meshes with the sector gear 71 of the torque output element 70.

[0039] The intermediate support member 10 has a first face 10 a facing the housing 30 , on which the gear power transmission system 60 is mounted, and a second face 10 b facing the electronic board 50 .

[0040] Figure 2The assembly of the elements in the housing 30 is shown more precisely. It can thus be seen that the intermediate support member 10 is attached to the housing by means of attachment means, in particular screws. A region of the intermediate support member 10 partially covers the output shaft of the electric motor, the same region of the intermediate support member 10 comprising a guide bearing 13 guiding the rotation of the output shaft of the electric motor 20.

[0041] The ribs protruding from the guide cylinder 14 extend on the second face 10 b of the intermediate support member and reinforce the intermediate support member 10 .

[0042] The cover 40 comprises an electrical connector for connecting the actuator to the vehicle power supply. An electronic board 50 is located between the intermediate support member 10 and the cover 40. The electronic board 50 is attached to the cover by attachment means, in particular clips. The electronic board is connected to the electrical connector and the electric motor 20 by conductive pins.

[0043] Figure 3 The arrangement of the gear drive train 60 cooperating with the sector gear 71 of the torque output element 70 is shown more precisely. During operation, the worm 21 of the shaft of the electric motor 20 meshes with the gear 61 via the first stage 62 of the gear 61, and the torque is then transmitted to the sector gear 71 of the torque output element 70 via the second stage 63 of the gear 61.

[0044] Figure 4 5 shows how the angular position of the torque output element 70 is restored. The torque output element 70 has a magnetic target 72 at its end opposite to the connector 73, which faces the sensor 51 mounted on the electronic board 50. The magnetic target 72 is glued, clamped or screwed to the torque output element. The torque output element 72 passes through the intermediate support member 10 from the first face 10a of the intermediate support member to the second face 10b via the opening 15. The intermediate support member 10 does not help to guide the rotation of the torque output element 72; there is a radial gap between the intermediate support member 10 and the torque output element 72.

[0045] Even though the invention has been described in connection with specific embodiments, it is quite clear that the invention is by no means restricted thereto and that the invention comprises all technical equivalents of the described means.

[0046] In the claims, any reference signs placed between parentheses shall not be construed as limiting the claim.

Claims

1. An actuator (1) for a parking lock system of a vehicle transmission gearbox, the actuator (1) comprising an intermediate support member (10), an electric motor (20) and a gear power transmission system (60) kinematically connected to the electric motor (20) being attached to the intermediate support member (10), the actuator (1) further comprising a torque output element (70) meshing with the gear power transmission system (60) and being rotationally movable between a locked position and an unlocked position, characterized in that The intermediate support member (10) and the torque output element (70) are accommodated in a housing (30), and the torque output element (70) is guided to rotate by the housing (30).

2. The actuator (1) according to claim 1, characterized in that The gear power transmission system (60) is a worm (21) and worm wheel (61) system, the worm (21) being on the output shaft of the electric motor (20).

3. The actuator (1) according to claim 2, characterized in that The end of the output shaft of the electric motor (20) is guided to rotate by the intermediate support member (10).

4. An actuator (1) according to any one of the preceding claims, characterized in that The electric motor (20) includes a front face (20a) mounted in an opening (11) of the intermediate support member (10) and a rear face (20b) held on the intermediate support member (10) by a compression plate (23) attached to the intermediate support member (10).

5. An actuator (1) according to any one of the preceding claims, characterized in that The electric motor (20) is fixed relative to the intermediate support member (10) to prevent rotation by means of lugs (12) extending from the intermediate support member (10) and cooperating with cutouts (22) of the electric motor (20).

6. An actuator (1) according to any one of claims 2 to 5, characterized in that The gear (61) is mounted so as to be rotatable on a shaft (31) which is mounted on the one hand in the intermediate support member (10) and on the other hand in the housing (30).

7. An actuator (1) according to any one of the preceding claims, characterized in that The torque output element (70) includes a sector gear (71) meshing with the gear power transmission system (60).

8. The actuator (1) according to claim 7 in combination with claim 2, characterized in that The gear system (61) is a two-stage system, the first stage (62) of the gear (61) meshes with the worm (21) of the output shaft of the electric motor (20), and the second stage (63) of the gear (61) meshes with the sector gear (71) of the torque output element (70).

9. An actuator (1) according to any one of the preceding claims, characterized in that The intermediate support member (10) has a first surface (10a) facing the housing (30) and a second surface (10b) facing the electronic board (50), and the gear power transmission system (60) is mounted on the first surface (10a).

10. The actuator (1) according to claim 9, characterized in that The torque output element (70) passes through the intermediate support member (10) and has a magnetic target (72) at its end opposite to the torque output, facing the sensor (51) mounted on the electronic board (50).

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