Actuator for a parking lock system of a vehicle transmission

Abstract

The present invention relates to an actuator for a parking lock system of a vehicle transmission, the actuator (1) comprising an electric motor (20) provided with a stator coil, a rotor and an output shaft (23) connected to the rotor and extending along an X-axis, and a speed reducer mechanism (70) having a rotatable torque output element (31) such that it can rotate between a locked position and an unlocked position, the speed reducer mechanism (70) being kinematically connected to the output shaft (23) of the electric motor (20), the electric motor (20) being of the brushless DC type, the actuator (1) comprising a first electronic board (50) and a second electronic board (40), the second electronic board (40) comprising a device for determining the position of the rotor of the electric motor (20).

Description

[Technical Field]

[0001] The present invention relates to an actuator for a parking lock system of a vehicle, in particular a transmission of a motor vehicle equipped with an automatic transmission, this locking system being commonly known as a park lock or parking lock. [Background technology]

[0002] Such actuators lock the transmission when parked by means of a lever that engages the gear teeth of the transmission.

[0003] A similar type of actuator is known from Patent Document 1. In this document, the actuator is equipped with a conventional brushed motor. A drawback of this type of brushed motor is that if the motor is not used for a long period of time, the brushes tend to adhere to the collector, which can cause the actuator to operate poorly. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] US Patent Application Publication No. 2019 / 136960 Summary of the Invention [Problem to be solved by the invention]

[0005] Since the parking lock system for a vehicle transmission is used only for short periods of time, it is preferable not to use a brushed motor to avoid the above-mentioned disadvantages.

[0006] Additionally, it is desirable for actuators for vehicle transmission parking lock systems to be small and lightweight, as miniaturization of such actuators is a particularly important criterion for automobile manufacturers. [Means for solving the problem]

[0007] The subject of the present invention is an actuator for a parking lock system of a transmission that improves on current solutions while meeting compactness and weight criteria.

[0008] More particularly, the present invention relates to an actuator for a parking lock system of a vehicle transmission, the actuator comprising: an electric motor provided with a stator coil, a rotor, and an output shaft connected to the rotor and extending along an X-axis; and a speed reducer mechanism having a rotatable torque output element kinematically connected to the output shaft of the electric motor so as to be able to rotate between a locked position and an unlocked position, the electric motor being of a brushless DC type, the actuator comprising a first electronic board and a second electronic board, the second electronic board comprising a device for determining the position of the rotor of the electric motor.

[0009] The term transmission also refers to the reduction gear associated with the electric motor in the case of an electric vehicle.

[0010] In this way, by using a brushless DC motor, the problem of the brushes sticking to the collector when not in use can be avoided. In addition, by arranging an actuator with two electronic boards, it is possible to miniaturize the actuator while maintaining high-performance control of the motor. The two electronic boards are spaced apart.

[0011] Advantageously, the speed reducer mechanism comprises a worm screw located on the output shaft of the electric motor and meshing with a gear on which the torque output element is mounted.

[0012] According to the present invention, the first electronic substrate extends in a plane P1 substantially parallel to the X axis, and the second electronic substrate extends in a plane P2 substantially perpendicular to the X axis.

[0013] According to one feature of the present invention, the first electronic board and the second electronic board are electrically connected by an L-shaped connecting element.

[0014] According to another feature of the invention, at least one multi-pole magnet, preferably a four-pole magnet, is attached to the output shaft of the electric motor, and the device for determining the position of the rotor of the electric motor on the second electronic board comprises at least one phase sensor, preferably three sensors, installed facing the multi-pole magnet to ensure electronic switching of the power supply to the stator coils of the electric motor.

[0015] According to the invention, the first electronic board comprises a position sensor facing the torque output element for determining its angular position.

[0016] According to one feature of the invention, the second electronic board comprises power supply pins, preferably three pins, for electrically supplying the stator coils of the electric motor.

[0017] Preferably, the second electronic board has an opening through which the output shaft of the electric motor passes, the opening having an open or closed contour.

[0018] According to the present invention, the electric motor, the output shaft of the electric motor, the speed reducer mechanism, the first electronic board, and the second electronic board are accommodated in an integrated housing. The housing is advantageously made of a plastic material to make the actuator as light as possible. Alternatively, the housing may be made of metal, for example aluminum.

[0019] Preferably, the housing defines a first volume in which the electric motor is accommodated and a second volume in which a reducer mechanism kinematically connected to the electric motor and two electronic boards are accommodated. Preferably, the first volume is closed by a first cover, and the second volume is closed by a second cover. As a result, the electric motor is assembled in its own container, then the remaining elements, i.e., the reducer mechanism and the two electronic boards, are assembled in their own containers, and finally the two containers are closed by their respective covers, making assembly of the actuator easy.

[0020] According to a further feature of the invention, the first electronic board is attached to the housing by means of a fastening screw, and the second electronic board is attached to the housing by means of at least one guide surface emanating from the housing.

[0021] According to the present invention, the housing includes electrical connectors for electrically connecting the first electronic board and the second electronic board to an external power supply.

[0022] Other features and advantages of the present invention will become apparent from the following detailed description of the embodiments, taken in conjunction with the accompanying drawings. [Brief explanation of the drawings]

[0023] [Figure 1] 1 shows a perspective view of an actuator according to the present invention; [Figure 2] 2 shows a partial cross-sectional view of the housing of the actuator according to FIG. 1; [Figure 3] A perspective view of the arrangement of the motor and two electronic boards is shown. [Figure 4] 1 shows a perspective view of the arrangement of the motor and two electronic boards from another point of view. [Figure 5] 1 shows a perspective view of an actuator according to the invention without the cover or first electronic board. DETAILED DESCRIPTION OF THE INVENTION

[0024] 1 shows an actuator 1 for a parking lock system for a transmission according to the invention. More precisely, this actuator 1 comprises a one-piece housing 10 made up of a first volume V1 and a second volume V2.

[0025] The first tubular volume V1 contains a brushless DC motor 20 with an output shaft 23. The second parallelepiped volume V2 mainly contains a reducer mechanism 70 kinematically connected to the motor 20 and two electronic boards 40, 50. The first volume V1 is closed by a first cover 12, and the second volume V2 is closed by a second cover 14. The first cover 12 is attached to the housing 10 by metal clips 13. The second cover 14 is attached to the housing 10 by any conventional fastening means, for example screws.

[0026] As will be explained with reference to the following figures, the speed reducer mechanism 70 is positioned on the output shaft 23 of the electric motor 20 and includes a worm screw 22 that meshes with a gear 30 on which a torque output element 31 is mounted. The torque output element 31 is manufactured in the form of a shaft concentric with the gear 30, and its end has the form of a star-shaped female connector into which an actuating rod (not shown) of a locking system for locking or unlocking the teeth of a transmission (not shown) can be inserted via an actuating lever (not shown). Alternatively, the torque output element 31 can be manufactured in the form of a male connector. The torque output element 31 is guided in rotation by a cylinder 80 of the housing 10. A sealing means is located within the cylinder 80 to prevent external contaminants from entering the interior of the actuator 1. Similarly, sealing means are provided between the cover 14 and the housing 10, and between the cover 12 and the housing 10.

[0027] The housing 10 also includes an electrical connector 15 for electrically connecting the internal components of the actuator 1 .

[0028] Fixing means 11 in the form of metallic inserts are arranged at several points on the housing 10 so that the housing 10 can be attached to the vehicle transmission. In the present case, three inserts 11 are provided.

[0029] FIG. 2 shows a coordinate system X, Y, Z. The direction or axis X corresponds to the longitudinal direction. The transverse direction or axis Y is defined as being perpendicular to the longitudinal direction X. More specifically, the longitudinal direction X and the transverse direction Y may, for example, belong to a substantially horizontal plane P1 (see FIG. 3). The direction or axis Z of the part corresponds to the vertical direction. More specifically, the transverse direction Y and the vertical direction Z may, for example, belong to a substantially vertical plane P2 (see FIG. 3).

[0030] This view more accurately shows the integration of the motor 20 and the speed reducer mechanism 70 within the housing 10.

[0031] The brushless DC motor 20 is provided with a stator coil, a rotor, and an output shaft 23 connected to the rotor and extending along the X-axis. There are three stator coils that form the stator of the motor.

[0032] A multi-pole magnet 21 is attached to the output shaft 23 of the electric motor 20. The magnet 21 is annular and coaxial with the output shaft 23. The magnet 21 has four poles. Of course, the magnet 21 can have a different number of poles.

[0033] The speed reducer mechanism 70 is located on the output shaft 23 of the electric motor 20 and includes a worm screw 22 that meshes with a gear 30 on which a torque output element 31 is mounted. The torque output element 31 extends along the Z axis. The end of the output shaft 23 opposite the electric motor 20 is guided for rotation within the housing receptacle 16, thereby functioning as a bearing.

[0034] The housing also contains a first electronic board 50 and a second electronic board 40 .

[0035] The first electronic board 50, which is the main electronic board of the actuator, enables electronic management of the actuator and integrates electronic components necessary for the operation of the 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 52 for sensing the angular position of the torque output element 31. The first electronic board 50 has a shape that is generally complementary to the shape of the periphery of the second volume V2 of the housing 10. The angular position sensor 52 is a Hall effect sensor. The first electronic board 50 is attached to the housing 10 by an opening 51 located on its periphery.

[0036] The second electronic board 40 comprises at least one device for determining the position of the rotor of the electric motor placed facing the multi-pole magnet 21 in order to provide the signals necessary for electronic switching of the power supply of the stator coils of the electric motor 20.

[0037] 3 shows more precisely the arrangement of the electric motor 20 and the two electronic boards 50, 40. The first electronic board 50 extends in a plane P1 substantially parallel to the X-axis, and the second electronic board 40 extends in a plane P2 substantially perpendicular to the X-axis. The multi-pole magnet 21 extends in the same plane P2. The second electronic board 40 has a substantially "U" shape with one leg of the "U" larger than the other leg. The larger leg is the leg facing the first electronic board 50. The second electronic board 40 has an opening 47 through which the output shaft 23 of the electric motor 20 passes. The multi-pole magnet 21 is also installed in the opening 47.

[0038] The device for determining the rotor position of the electric motor 20 on the second electronic board 40 comprises at least one phase sensor 41, 42, 43, which is placed facing the multi-pole magnet 21 in order to ensure electronic switching of the power supply to the stator coils of the electric motor 20. More precisely, the three sensors 41, 42, 43 are distributed on the second electronic board 40 concentrically with respect to the X-axis, so that the three sensors 41, 42, 43 surround the multi-pole magnet 21. The three sensors are Hall effect sensors.

[0039] The second electronic board 40 also has power supply pins 44, 45, 46 for electrically supplying the stator coils of the electric motor 20. There are three of these pins 44, 45, 46, and therefore it is possible to supply power to three stator coils of the electric motor 20. These three pins 44, 45, 46 are distributed on the second electronic board 40 concentrically about the X axis, alternating with the three sensors 41, 42, 43.

[0040] 4 shows the connection between two electronic boards 50, 40. The first electronic board 50 and the second electronic board 40 are electrically connected by an L-shaped connecting element 60.

[0041] 5 shows the actuator 1 without the cover 14 or the first electronic board 50, but shows the fixing screws 18 for fixing the first electronic board 50. These fixing screws 18 pass through openings 51 in the first electronic board 50. The first electronic board 50 rests on pegs 19 in the housing 10, and the fixing screws 18 are threaded into these pegs 19.

[0042] 5 also shows in detail the mounting of the second electronic board 40. This second electronic board 40 is mounted to the housing 10 by means of guide surfaces 17 emanating from the housing 10. In the present case, two guide surfaces are required, distributed on both lateral ends of the second electronic board 40.

[0043] The housing 10 also has a cavity in which the gear 30 is housed, the cavity substantially conforming to the shape of the gear 30 .

[0044] This FIG. 5 also shows the opposite end of the shaft of the torque output element 31, this end of the shaft being located facing the angular position sensor 52 on the first electronic board 50.

[0045] Although the present invention has been described with reference to particular embodiments, it is to be understood that the invention is in no way limited thereto, but includes all technical equivalents of the means described.

[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, comprising: The actuator (1) comprises: an electric motor (20) provided with a stator coil, a rotor, and an output shaft (23) connected to the rotor and extending along an X-axis; and a speed reducer mechanism (70) having a torque output element (31) rotatable between a locked position and an unlocked position, the speed reducer mechanism (70) being kinematically connected to the output shaft (23) of the electric motor (20); the electric motor (20) is of the brushless DC type, the actuator (1) comprises a first electronic board (50) and a second electronic board (40), the second electronic board (40) comprising a device for determining the position of the rotor of the electric motor (20), The first electronic substrate (50) extends in a plane P1 substantially parallel to the X-axis, and the second electronic substrate (40) extends in a plane P2 substantially perpendicular to the X-axis, The actuator (1), wherein the second electronic board (40) has an opening (47) through which the output shaft (23) of the electric motor (20) passes.

2. 2. The actuator (1) according to claim 1, characterized in that the first electronic board (50) and the second electronic board (40) are electrically connected by an L-shaped connecting element (60).

3. 2. The actuator (1) according to claim 1, characterized in that at least one multi-pole magnet (21) is attached to the output shaft (23) of the electric motor (20), and the device for determining the position of the rotor of the electric motor (20) on the second electronic board (40) comprises at least one phase sensor (41, 42, 43) installed facing the multi-pole magnet (21) to ensure electronic switching of the power supply to the stator coils of the electric motor (20).

4. 2. An actuator (1) according to claim 1, characterized in that the first electronic board (50) comprises a position sensor (52) facing the torque output element (31) for determining its angular position.

5. 2. The actuator (1) according to claim 1, characterized in that the second electronic board (40) comprises power supply pins (44, 45, 46) for electrically supplying the stator coils of the electric motor (20).

6. 6. The actuator (1) according to claim 1, wherein the electric motor (20), the output shaft (23) of the electric motor (20), the speed reducer mechanism (70), the first electronic board (50), and the second electronic board (40) are accommodated in an integrated housing (10).

7. 7. The actuator (1) according to claim 6, characterized in that the first electronic board (50) is attached to the housing (10) by means of fixing screws, and the second electronic board (40) is attached to the housing (10) by means of at least one guide surface (17) emanating from the housing (10).

8. 7. The actuator (1) according to claim 6, characterized in that the housing (10) comprises an electrical connector (15) for electrically connecting the first electronic board (50) and the second electronic board (40) to an external power supply source.

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