Actuator for vehicle gearbox parking lock system

Abstract

The invention relates to an actuator (1) for a vehicle gearbox parking lock system, the actuator (1) comprising a housing (10) having a first volume (V1) in which an electric motor (20) having a front face (20a) and a rear face (20b) is housed, and a second volume (V2) in which a speed reduction mechanism (70) and a torque output element (80) movably connected to the electric motor (20) are housed, according to the invention, the first volume (V1) is separated from the second volume (V2) by a wall (19) in which is formed a circular opening (100) for the passage of the output shaft (23) of the electric motor (20), the opening (100) comprising at least one flat portion (100a, 100b, 100c) arranged at the periphery thereof, and the front face (20a) of the electric motor (20) is accommodated in the opening (100) so as to be in contact with said at least one flat portion (100a, 100b, 100c).

Description

Technical Field

[0001] The invention relates to an actuator for a parking lock system for a vehicle gearbox, in particular a motor vehicle equipped with an automatic gearbox, such as a hybrid vehicle. The invention also applies to parking lock systems for a retarder associated with an electric vehicle motor. Such locking systems are more commonly known as parking locks or parking locks. Background Art

[0002] This actuator allows the gearbox to be locked when the car is parked by means of a rod engaging the teeth of the gearbox.

[0003] An actuator of the same type is known from document US2019136960 AA, in which a gear and worm system is used to transmit the rotational movement of an electric motor to a torque output element of the actuator.

[0004] To minimize wear on the gear and worm system, the center-to-center distance between the worm and the gear must be of high precision. This precision is not compatible with the molding process of the plastic that partially constitutes the gear system. The required precision is on the order of one micron, and the plastic only allows a deviation of + / -50 microns.

[0005] To this end, it is necessary to position the electric motor very accurately relative to the housing accommodating the reduction mechanism, rather than forcibly inserting the electric motor into the housing. There is a risk of reducing the service life of the rolling bearing or internal bearing of the electric motor due to excessive radial compression. Summary of the invention

[0006] One of the purposes of the present invention is to propose a solution to the problem. To this end, the present invention proposes an actuator for a parking lock system of a vehicle transmission, the actuator comprising a housing having a first volume and a second volume, the first volume accommodating an electric motor having a front face and a rear face, the second volume accommodating a speed reduction mechanism and a torque output element movably connected to the electric motor, the first volume being separated from the second volume by a wall, the wall being formed with a circular opening for the output shaft of the electric motor to pass through, the opening comprising at least one flat portion arranged at its periphery, and the front face of the electric motor being accommodated in the opening so as to contact the at least one flat portion.

[0007] This arrangement has the advantage of minimizing the contacts or contact points of the front face of the electric motor in the housing, while ensuring a reliable and functional mounting of the electric motor in the housing, allowing minimum wear of the gear and worm system. This arrangement also has the advantage of completely fixing the front face of the electric motor in the housing without creating play at the rolling bearings or internal bearings of the front face, which play could cause defects in the electric motor due to poor fixing in the event of vibrations.

[0008] According to the invention, the front face of the motor is cylindrical.The part of the motor which receives the rolling bearing or the bearing for rotationally guiding the motor shaft is referred to as the front face of the motor.

[0009] According to the invention, three flat portions are arranged at the periphery of the circular opening, and two of these flat portions are arranged on opposite sides of the reduction mechanism relative to the output shaft of the electric motor. This arrangement with three flat portions ensures a more reliable and functional installation of the electric motor in the housing.

[0010] According to one feature of the invention, the two flat portions are arranged on opposite sides of the reduction mechanism relative to the output shaft of the electric motor. This arrangement allows the forces generated by the reduction mechanism to be opposite.

[0011] Advantageously, the groove is formed in the wall facing the flat portion to allow bending of the material of the wall between the flat portion and the groove. Preferably, the material distance between the flat portion of the wall and the groove is 1 mm to 3 mm. This arrangement makes it possible to accept variations in tolerances while ensuring zero play when the front face of the electric motor engages in the circular opening.

[0012] According to the invention, each flat portion is angularly spaced apart by substantially 120°, which allows for an optimal arrangement around the perimeter of the circular opening. A tolerance of plus or minus 10% may be applied.

[0013] According to an additional feature of the invention, the wall comprises at least one channel for at least one power pin of the electric motor. Preferably, there are three channels for three power pins of the electric motor. This arrangement allows the electric motor to be connected to an external power source that is not located in the first volume.

[0014] According to the invention, the first volume extends partially into the second volume. Preferably, the housing is in one piece and is plastic. These features make it possible to obtain an actuator that is compact, light and easy to manufacture.

[0015] According to the invention, the first volume is closed by a first cover which centers the rear face of the electric motor and allows the front face of the electric motor to remain in position in the circular opening. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Other features and advantages of the present invention will become apparent from reading the following detailed exemplary embodiments with reference to the accompanying drawings:

[0017] Figure 1 shows a perspective view of an actuator according to the present invention;

[0018] Figure 2 shows a cross-sectional view of an actuator according to the present invention;

[0019] Figure 3 Shows Figure 1Cross-sectional view of BB. DETAILED DESCRIPTION

[0020] 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 present invention should not be limited to the embodiments disclosed in the specification.

[0021] Figure 1 An actuator 1 for a parking lock system of a gearbox according to the invention is shown. In the case of electric vehicles, the term gearbox also refers to a reduction gear associated with the electric motor. More precisely, the actuator 1 comprises a one-piece housing 10 constituted by a first volume V1 and a second volume V2.

[0022] In the first tubular volume V1 there is an electric motor 20 of the brushless DC type, comprising an output shaft 23. Any other type of electric motor is within the scope of the invention, such as a brushed DC electric motor. The second volume V2 of parallelepiped shape mainly houses a reduction gear mechanism 70, which is kinematically connected to the electric motor 20 and to two electronic boards. The first volume V1 is closed by a first cover 12 and the second volume V2 by a second cover. The first cover 12 is attached to the housing 10 by a metal clip 13. The second cover is attached to the housing 10 by any conventional fixing means, such as screws.

[0023] The reduction mechanism 70 includes a worm 22, which is positioned on the output shaft 23 of the electric motor 20 and meshes with the gear 30 on which the torque output element 80 is located. The torque output element 80 is manufactured in the form of a shaft concentric with the gear 30, and its end is in the form of a star-shaped female connector, into which the actuating rod (not shown) of the locking system can be engaged, so as to lock or unlock the teeth of the gearbox (not shown) via the actuating rod or latch (not shown). Optionally, the torque output element 80 can be made in the form of a male connector. The torque output element 80 is guided in rotation by the barrel of the housing 10. A sealing device is located in the barrel to ensure that external contaminants do not enter the interior of the actuator 1. Similarly, a sealing device is provided between the cover 14 and the housing 10 and between the cover 12 and the housing 10.

[0024] Figure 1 It is also shown that the first volume V1 is separated from the second volume V2 by a wall 19 in which a circular opening 100 is formed to allow the output shaft 23 of the electric motor 20 to pass through. Figure 1 In the embodiment of FIG. 1 , the opening includes three flat portions 100a, 100b, 100c arranged at its periphery, and the front face 20a of the electric motor 20 is received in the opening 100 so as to be in contact with the flat portions 100a, 100b, 100c. Figure 3This circular opening 100 is described in detail. The wall 19 also comprises three channels 120 , 130 , 140 for the three power supply pins of the electric motor 20 .

[0025] The housing 10 is in one piece and is made of plastic. The first volume V1 partially extends into the second volume V2. The housing 10 also comprises an electrical connector 15 for electrically connecting the components inside the actuator 1.

[0026] Fixing means 11 in the form of metal inserts are arranged in a number of locations of the housing 10 so that the housing 10 can be attached to a gearbox of a vehicle. In this example, three inserts 11 are provided.

[0027] Figure 2 A coordinate system X, Y, Z is shown. The direction or axis X corresponds to the longitudinal direction. The transverse direction or axis Y is defined to be perpendicular to the longitudinal direction X. The direction or axis Z for its part corresponds to the vertical direction.

[0028] Should Figure 2 The integration of the electric motor 20 in the housing 10 is more precisely shown. The electric motor 20 of the brushless DC type is provided with a stator coil, a rotor and an output shaft 23 connected to the rotor and extending along the axis X. There are three stator coils forming the stator of the electric motor. The electric motor has a front face 20 a and a rear face 20 b, the front face 20 a of the electric motor 20 being housed in the opening 100.

[0029] The multi-pole magnet 21 is attached to the output shaft 23 of the electric motor 20. The magnet 21 is annular in shape and is coaxial with the output shaft 23. The magnet 21 has four poles. Of course, the magnet 21 may have a different number of poles.

[0030] The reduction gear mechanism 70 comprises a worm 22 positioned on the output shaft 23 of the electric motor 20 and meshing with a gear 30 on which a torque output element 80 is located. The torque output element 80 extends along the axis Z.

[0031] The output shaft 23 of the electric motor 20 is guided in rotation by three rolling bearings and / or bearings. Figure 2 In the embodiment of FIG. 1 , the first bearing 18 and the rolling bearing 17 are accommodated at both ends of the frame of the electric motor, and the bearing 16 is accommodated in the housing 10 to guide the end of the output shaft 23 opposite to the rotor. More specifically, the rolling bearing 17 is accommodated in the front face 20a of the electric motor 20, and the bearing 18 is accommodated in the rear face 20b of the electric motor 20.

[0032] The first volume V1 is closed by a first cover 12 which centers the rear face 20b of the electric motor 20 and allows the front face 20a of the electric motor 20 to remain in place in the circular opening 100. To this end, the first cover 12 has an annular shape for engagement with the rear face 20b of the electric motor. A spring system is arranged between the first cover and the electric motor 20 so as to press the electric motor 20 axially against the housing 10 and / or the wall 19.

[0033] The opening 100 separates the first volume from the second volume and Figure 3 Discussed in more detail in .

[0034] The housing 10 also receives two electronic boards, namely a main electronic board and a secondary electronic board. Figure 2 Only the secondary electronic board 40 is visible. The main electronic board of the actuator allows the electronic management of the actuator and integrates the electronic components required for the operation of the electric motor, such as, but not limited to, at least one capacitor, at least one resistor, at least one central processing unit (CPU) and a sensor for sensing the angular position of the torque output element 80. The main electronic board has a shape that is substantially complementary to the peripheral shape of the second volume V2 of the housing 10. The angular position sensor is a Hall effect sensor. The secondary electronic board 40 includes at least one device for determining the position of the rotor of the electric motor positioned facing the multipolar magnet 21, so as to provide the signals required for the electronic switching of the power supply of the stator coils of the electric motor 20.

[0035] Figure 3 More precisely, the circular opening 100 and the three flat portions 100a, 100b, 100c arranged at the periphery are shown. Two of these flat portions 100a, 100b are arranged on the opposite side of the reduction mechanism 70 relative to the output shaft 23 of the electric motor 20; this feature is shown as Figure 1 shown.

[0036] A groove 110 is formed in the wall 19 facing the third flat portion 100c to allow bending of the material of the wall 19 between the third flat portion 100c and the groove 110. The material distance d between the flat portion 100a and the groove 110 of the wall 19 is 1 mm to 3 mm to allow optimal bending without weakening the wall. Each flat portion 100a, 100b, 100c is angularly spaced 120° apart. The wall 19 comprises three channels 120, 130, 140 for the three power pins of the electric motor 20.

[0037] 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 encompasses all technical equivalents of the described means.

[0038] 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, the actuator (1) comprising a housing (10), the housing (10) having a first volume (V1) and a second volume (V2), the first volume (V1) accommodating an electric motor (20) having a front face (20a) and a rear face (20b), the second volume (V2) accommodating a speed reduction mechanism (70) and a torque output element (80) movably connected to the electric motor (20), the first volume (V1) being separated from the second volume (V2) by a wall (19), the wall (19) being formed with a circular opening (100) for the output shaft (23) of the electric motor (20) to pass through, characterized in that: The opening (100) includes at least one flat portion (100a, 100b, 100c) arranged at a periphery thereof, and a front face (20a) of the electric motor (20) is received in the opening (100) so as to contact the at least one flat portion (100a, 100b, 100c).

2. The actuator (1) according to claim 1, characterized in that Three flat portions (100a, 100b, 100c) are arranged at the periphery of the circular opening (100).

3. The actuator (1) according to claim 1 or 2, characterized in that Two flat portions (100a, 100b) are arranged on opposite sides of the speed reduction mechanism (70) relative to the output shaft (23) of the electric motor (20).

4. An actuator (1) according to any one of the preceding claims, characterized in that A groove (110) is formed in the wall (19) facing the flat portion (100c) to allow bending of the material of the wall (19) between the flat portion (100c) and the groove (110).

5. The actuator (1) according to claim 4, characterized in that The distance (d) of the material between the flat portion (100c) and the groove (110) of the wall (19) is 1 mm to 3 mm.

6. An actuator (1) according to any one of claims 2 to 5, characterized in that Each flat portion (100a, 100b, 100c) is angularly spaced apart by approximately 120°.

7. An actuator (1) according to any one of the preceding claims, characterized in that The wall (19) comprises at least one channel (120, 130, 140) for at least one power supply pin of the electric motor (20).

8. Actuator (1) according to one of the preceding claims, characterized in that The first volume (V1) partially extends into the second volume (V2).

9. An actuator (1) according to any one of the preceding claims, characterized in that The housing (10) is in one piece and is made of plastic.

10. An actuator (1) according to any one of the preceding claims, characterized in that The first volume (V1) is closed by a first cover (12) which centers the rear face (20b) of the electric motor (20) and allows the front face (20a) of the electric motor (20) to remain in place in the opening (100).

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