Actuator for a vehicle transmission parking lock system

Abstract

The present invention relates to an actuator (1) for a parking lock system for a vehicle transmission. Said actuator (1) comprises a housing (30), an intermediate support (10) which supports an electric motor (20) extending axially along an axis X. The electric motor (20) is axially fixed to the intermediate support (10) by a compression plate (23). At least one mounting tab (37) extending from the housing (30) engages with the compression plate (23) to radially fix the electric motor (20). (See Figure 2 for abbreviations.)

Description

Title of the invention: Actuator for a parking lock system of a vehicle transmission

[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, for example a hybrid vehicle. The invention also applies to a parking lock system of a reducer associated with an electric vehicle motor. The gearbox or reducer will more generally be called a transmission box. This locking system is better known by its English term "park-lock" or "parking lock".

[0002] Such an actuator allows the transmission box to be locked in parking by means of a lever engaging with a toothing of the transmission box.

[0003] Actuators of this type are known and are conventionally designed with a toothed wheel and worm gear system to transmit the rotational movement of an electric motor to a torque output element of the actuator. For example, documents US 2019136974 AA and DE 102019100300 A1 describe such actuators.

[0004] A problem associated with these architectures is the reliable fixing of the electric motor. Space constraints do not allow for correct fixing of the electric motor by screwing alone. It is therefore necessary for the motor to be held axially and radially in order to withstand vibrations while having a simple design to limit the associated costs. In addition, a simple assembly process is required.

[0005] Thus, the invention proposes an actuator for a parking locking system of a vehicle transmission box, said actuator comprises a housing, an intermediate support which supports an electric motor extending axially along an axis X, the electric motor is held fixed to the intermediate support by a compression plate, at least one fixing lug coming from the housing engages with the compression plate in order to radially hold the electric motor.

[0006] The compression plate allows the electric motor to be held axially against the intermediate support. This compression plate also allows it to absorb significant forces and shocks from the locking system, in particular by the ratcheting effect. The fixing lug(s) allow the electric motor to be held radially.

[0007] According to the invention, the fixing lug comes from the housing and engages with the Snap-in compression plate. In other words, the mounting bracket is a single piece with the housing. To achieve this snap-in, the mounting bracket has a hook-shaped end. This simple design results in a compact actuator, reduces the number of components and also reduces assembly time.

[0008] According to a characteristic of the invention, two fixing lugs are positioned radially on either side of the electric motor.

[0009] According to a characteristic of the invention, the electric motor comprises a front face and a rear face, said front face is mounted in an opening of the intermediate support and the rear face is held to the intermediate support by the compression plate.

[0010] According to the invention, the compression plate is metallic.

[0011] According to an additional characteristic of the invention, the compression plate is preferably “U” shaped.

[0012] According to the invention, the housing is closed by a cover and the cover comprises at least one surface which, when the cover is assembled on the housing, prevents radial movement of the fixing lug. There is thus no axial force between the housing and the cover, which could harm their assembly.

[0013] According to the invention, the housing and the cover are made of plastic.

[0014] According to the invention, a gear power transmission system is in kinematic connection with the electric motor. The actuator further comprises a torque output element meshing with the geared power transmission system and rotatable between a locking position and an unlocking position.

[0015] According to another characteristic of the invention, the gear power transmission system is a toothed wheel and worm screw system, said worm screw being located on an output shaft of the electric motor. According to the invention, the torque output element comprises a toothed sector meshing with the gear power transmission system.

[0016] Other characteristics and advantages of the invention will emerge from the following reading of a detailed example embodiment, with reference to the appended figures:

[0017] [Fig.l] represents an exploded perspective view of the actuator according to the invention;

[0018] [Fig.2] represents a perspective top view of the actuator of [Fig.l] without the cover;

[0019] [Fig.3] represents a sectional view AA of the actuator of [Fig.2].

[0020] It should be noted that the figures disclose the invention in a manner sufficiently detailed for its implementation, said figures helping to better define the invention if necessary. The invention should not, however, be limited to the embodiment disclosed in the description.

[0021] Referring from [Fig.l] to [Fig.3], the actuator 1 mainly comprises a housing 30, a drive electric motor 20, a geared power transmission system 60, an intermediate support 10, a torque output element 70, an electronic card 50 and a cover 40. The geared power transmission system 60 reduces the speed and increases the torque of the electric motor 20. A gear train may optionally be kinematically located between the electric motor 20 and the torque output element 70. The housing 30 and the cover 40 form, once assembled together, an internal volume in which the electric motor 20, the geared power transmission system 60, the intermediate support 10, the torque output element 70 and the electronic card 50 are housed.The housing 30 and the cover 40 can be assembled together by any type of sealed fastening, for example screwing, gluing or by laser welding, ultrasound. The housing 30 and the cover 40 are made of plastic, in particular of PBT reinforced with fiberglass. A semi-permeable membrane, i.e. permeable to gases and impermeable to liquids, is housed in the housing 30 or in the 40 in order to automatically regulate the pressure inside the actuator 1.

[0022] The housing is capable of being fixed to a transmission box by means of fixing means passing through openings 36 of the housing. The housing 30 is thus positioned precisely with the transmission box.

[0023] The torque output element 70 is produced in the form of a shaft, one end of which has the form of a star-shaped female socket 73 in which an actuating rod (not shown) of a locking system is capable of engaging so as to lock or unlock a toothing of the transmission box (not shown) via an actuating lever or latch (not shown). Alternatively, the torque output element 70 can be produced in the form of a male socket. The torque output element 70 comprises a toothed sector 71 meshing with the gear power transmission system 60.

[0024] The housing 30 comprises an opening 32 in the form of a guide barrel in which the torque output element 70 is mounted. Thanks to precise tolerancing between the opening 32 and the torque output element 70, precise rotational guidance allows the torque output element 70 to move between a locking position and an unlocking position. A sealing means 33 is positioned concentrically with the opening 32 in order to ensure that external pollutants do not enter the interior of the actuator 1, for example here a lip seal. Similarly, a sealing means 34 is provided between the housing 30 and the transmission box, for example here an O-ring.

[0025] The intermediate support 10 supports the electric motor 20 and the system of gear power transmission system 60 in order to guarantee precise assembly tolerances between these two elements. The intermediate support 10 thus guides the rotation of the gear power transmission system 60. The gear power transmission system 60 is kinematically connected to the electric motor 20 and to the torque output element 70. The intermediate support 10, the electric motor 20 and the gear power transmission system 60 form a sub-assembly that can be easily integrated into the housing 30.

[0026] The gear power transmission system 60 is a gear wheel and worm screw system 21. The worm screw 21 is located on an output shaft of the electric motor 20. The end of the output shaft 21 of the electric motor 20 is guided in rotation by a bearing made of the same material as the intermediate support 10.

[0027] 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 complementarity with a bearing internal to the electric motor. The front face 20a is mounted in an opening 11 of the intermediate support 10 and the rear face 20b is held to the intermediate support 10 by a compression plate 23 fixed to the intermediate support 10.

[0028] The electric motor 20 is locked in rotation relative to the intermediate support 10 by means of a lug originating from the intermediate support 10 and cooperating with a notch in the electric motor 20. The intermediate support 10 has a complementary shape with the external casing of the electric motor 20 at its front face 20a, for example here two half-shells made from the same material as the intermediate support 10.

[0029] The toothed wheel of the gear power transmission system 60 is mounted so as to be rotatable on a shaft 31 which is mounted mainly in the intermediate support 10 but also in the housing 30. For this purpose, the intermediate support 10 comprises a means for fixing the shaft 31 in the form of a barrel 14 and the housing 30 also comprises a means for guiding the shaft 31 in the form of a barrel 35. The shaft 31 is mounted clamped or fitted in the barrel 14 of the intermediate support and the shaft 31 is mounted sliding in the barrel 35 of the housing. The toothed wheel is a double-stage design, the first stage of the toothed wheel meshing with the worm 21 of the output shaft of the electric motor 20 and the second stage of the toothed wheel meshing with the toothed sector 71 of the torque output element 70.

[0030] The intermediate support 10 has a first face on which the gear power transmission system 60 is mounted, located opposite the housing 10, and a second face located opposite the electronic card 50.

[0031] The cover 40 includes an electrical connector for connecting the actuator to an electrical source of the vehicle. The electronic card 50 is located between the inter support intermediate 10 and the cover 40. The electronic card 50 is fixed to the cover by fixing means, in particular clips. The electronic card is connected both to the electrical connector and to the electric motor 20 via conductive pins.

[0032] [Fig. 2] shows more precisely the attachment of the electric motor 20 to the intermediate support 10. The compression plate 23 is a metal strip with elastic properties. The compression plate 23 is U-shaped. The rear face 20b of the electric motor is housed in an opening 24 of the compression plate 23 by complementary shape. The compression plate 23 is fixed to the intermediate support 10 by fixing means, in particular two screws, located axially on either side of the front face 20a of the electric motor 20. The compression plate also comprises two lugs 25 bearing on the rear face 20b of the electric motor 20. These two lugs 25 are located on the periphery of the opening 24 and are diametrically opposed.

[0033] The compression plate 23 makes it possible to hold the electric motor 20 axially along the X axis against the intermediate support 10. In the embodiment illustrated in this [Fig.2] two fixing lugs 37 are positioned radially on either side of the electric motor 20. Optionally, the fixing lugs 37 are axially offset, that is to say they are not opposite each other. The fixing lugs 37 make it possible to hold the electric motor 20 radially along the Y and Z axes.

[0034] The fixing lugs 37 come from the housing 30 and engage with the compression plate 23 by snap-fastening. The fixing lugs are integral with the housing 30. To achieve this snap-fastening, the fixing lugs have a hook-shaped end 38. The hooks cooperate with the upper surface of the compression plate 23.

[0035] [Fig. 3] shows more precisely the cooperation between the cover 40 and the fixing lugs 37. The cover 40 comprises at least one surface 41 which when the cover 40 is assembled on the housing 30 prevents a radial movement of the fixing lugs 37 away from the compensation plate 23, that is to say in the open position of the fixing lugs 37.

[0036] Although the invention has been described in connection with a particular embodiment, it is quite obvious that it is in no way limited thereto and that it includes all the technical equivalents of the means described.

[0037] In the claims, the reference symbols in parentheses should not be interpreted as a limitation of the claim.

Claims

Claims

1. Actuator (1) for a parking lock system of a vehicle transmission, said actuator (1) comprises a housing (30), an intermediate support (10) which supports an electric motor (20) extending axially along an axis X, the electric motor (20) is axially fixed to the intermediate support (10) by a compression plate (23), at least one fixing lug (37) coming from the housing (30) engages with the compression plate (23) in order to radially fix the electric motor (20) characterized in that the housing (30) is closed by a cover (40) and the cover (40) comprises at least one surface (41) which when the cover (40) is assembled on the housing (30) prevents radial movement of the fixing lug (37).

2. Actuator (1) according to claim 1, characterized in that the fixing lug (37) coming from the housing (30) engages with the compression plate (23) by snap-fastening, said fixing lug (37) having a hook-shaped end (38).

3. Actuator (1) according to claim 2, characterized in that two fixing lugs (37) are positioned radially on either side of the electric motor (20).

4. Actuator (1) according to one of the preceding claims, characterized in that the electric motor (20) comprises a front face (20a) and a rear face (20b), said front face (20a) is mounted in an opening (11) of the intermediate support (10) and the rear face (20b) is held to the intermediate support (10) by the compression plate (23).

5. Actuator (1) according to one of the preceding claims, characterized in that the compression plate (23) is metallic.

6. Actuator (1) according to one of the preceding claims, characterized in that the compression plate (23) is preferably in the shape of a “TT”

7. \\ VJ / / . Actuator (1) according to one of the preceding claims, characterized in that the housing (30) and the cover are made of plastic.

8. Actuator (1) according to one of the preceding claims, characterized in that a gear power transmission system (60) is kinematically connected to the electric motor (20), said actuator (1) further comprises a torque output element (70) meshing with the gear power transmission system (60) and rotatable between a locking position and an unlocking position.

9. Actuator (1) according to claim 8, characterized in that the gear power transmission system (60) is a toothed wheel (61) and worm screw (21) system, said worm screw (21) is located on an output shaft of the electric motor (20) and the torque output element (70) comprises a toothed sector (71) meshing with the gear power transmission system (60).

Images