Actuator for a vehicle gearbox parking lock system

Abstract

The present invention relates to an actuator for a parking lock system of a vehicle gearbox, said actuator (1) comprises an electric motor (20) provided with stator coils, a rotor and an output shaft (23) connected to the rotor and extending along an axis X, a reduction mechanism (70) having a torque output element (31) rotating so as to be able to rotate between a locking position and a release position, said reduction 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 and in that the actuator (1) comprises a first electronic board (50) and a second electronic board (40), said second electronic board (40) comprising a device for determining the position of the rotor of the electric motor (20),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. Figure for the abbreviation: Figure 2,

Description

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

[0001] The invention relates to an actuator for a parking locking system of a vehicle gearbox, in particular a motor vehicle equipped with an automatic gearbox. This locking system is better known by its English term "park-lock" or "parking lock".

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

[0003] An actuator of the same type is known from document US 2019136960 AA. In this document, the actuator comprises a traditional brushed electric motor. A disadvantage of this type of brushed electric motor is that the brushes tend to stick to the commutator when the motor is not used for a long period, which can cause degraded operation of the actuator.

[0004] A parking lock system of a vehicle gearbox is only used for a very short time, it is therefore preferable not to use a brushed electric motor to avoid the inconvenience mentioned above.

[0005] Furthermore, the compactness of this type of actuator is a particularly important criterion for automobile manufacturers; it is therefore desirable that the actuators of the parking lock system of a vehicle gearbox be compact and lightweight.

[0006] The present invention relates to an actuator for a parking locking system of a gearbox improving current solutions while meeting the criteria of compactness and weight.

[0007] More particularly, the invention relates to an actuator for a parking lock system of a vehicle gearbox, said actuator comprising an electric motor provided with stator coils, a rotor and an output shaft linked to the rotor and extending along an X axis, a reduction mechanism having a rotary torque output element so as to be able to rotate between a locking position and a release position, said reduction mechanism being kinetically linked to the output shaft of the electric motor. The electric motor is of the brushless direct current type and the actuator comprises a first electronic card and a second electronic card, said second electronic card comprises a device for determining the position of the rotor of the electric motor.According to the invention, the first electronic card extends in a plane PI substantially parallel to the X axis and the second electronic card extends in a plane P2 sen- . possibly perpendicular to the X axis

[0008] The term gearbox also designates a reducer associated with an electric motor in the case of an electric vehicle.

[0009] Thus, the use of a brushless direct current electric motor makes it possible to overcome the problems of the brushes sticking to the collector during periods of non-use. In addition, the arrangement of an actuator with two electronic cards allows for compactness of the actuator while combining efficient control of the electric motor. The two electronic cards are separate.

[0010] Advantageously, the reduction mechanism comprises a worm screw positioned on the output shaft of the electric motor and meshes with a toothed wheel on which the torque output element is located.

[0011] According to a characteristic of the invention, the first electronic card and the second electronic card are electrically connected via an “L” shaped connection element.

[0012] According to another characteristic of the invention, at least one multi-pole magnet, preferably four poles, is fixed on the output shaft of the electric motor. The device for determining the position of the rotor of the electric motor of the second electronic card comprises at least one phase sensor, preferably three sensors, located opposite the multi-pole magnet in order to ensure the electronic switching of the power supply to the stator coils of the electric motor.

[0013] According to the invention, the first electronic card comprises a position sensor with respect to the torque output element in order to determine its angular position.

[0014] According to a characteristic of the invention, the second electronic card comprises power supply pins, preferably three pins, in order to electrically supply the stator coils of the electric motor in order to electrically supply the stator coils of the electric motor.

[0015] Preferably, the second electronic card comprises an opening through which the output shaft of the electric motor passes. This opening may have an open or closed contour.

[0016] According to the invention, the electric motor, the output shaft of the electric motor, the reduction mechanism, the first electronic card and the second electronic card are housed in a single-piece housing. The housing is advantageously made of a plastic material in order to make the actuator as light as possible. Alternatively, the housing can be made of metal, for example aluminum.

[0017] Preferably, the housing defines a first volume in which the electric motor is housed and a second volume in which the reduction mechanism is housed in kinematic connection with the electric motor and the two electronic cards. Preferably, the first volume is closed by means of a first cover and the second volume is closed by means of a second cover. This makes the assembly of the actuator easier because the electric motor is inserted into its own housing, then the remaining elements, i.e. the reduction mechanism and the two electronic cards are inserted into their own housing and the two housings are finally closed by their respective covers.

[0018] According to an additional characteristic of the invention, the first electronic card is fixed to the housing by means of fixing screws and the second electronic card is fixed to the housing by means of at least one slide coming from the housing.

[0019] According to the invention, the housing comprises an electrical connector for electrically connecting the first electronic card and the second electronic card to an external electrical power source.

[0020] Other characteristics and advantages of the invention will emerge from the following reading of a detailed example embodiment, with reference to the appended figures:

[0021] [Fig.l] represents a perspective view of the actuator according to the invention;

[0022] [Fig. 2] represents a partial sectional view of the actuator housing according to the [Fig.l];

[0023] [Fig.3] represents a perspective view of the arrangement of the electric motor and the two electronic cards;

[0024] [Fig.4] represents a perspective view of the arrangement of the electric motor and the two electronic cards from another point of view;

[0025] [Fig. 5] represents a perspective view of the actuator according to the invention without the cover or the first electronic card.

[0026] [Fig. 1] represents an actuator 1 of a parking locking system of a gearbox according to the invention. More precisely, this actuator 1 comprises a single-piece housing 10 composed of a first volume VI and a second volume V2.

[0027] In the first volume VI of tubular shape there is an electric motor 20 of the brushless direct current type, this electric motor comprises an output shaft 23. In the second volume V2 of parallelepiped shape there is mainly a reduction mechanism 70 in kinematic connection with the electric motor 20 and two electronic cards 40, 50. The first volume VI is closed by means of a first cover 12 and the second volume V2 is closed by means of a second cover 14. The first cover 12 is fixed to the housing 10 by means of metal clips 13. The second cover 14 is fixed to the housing 10 by any conventional fixing means, for example screws.

[0028] As will be explained with reference to the following figures, the reduction mechanism 70 comprises a worm screw 22 positioned on the output shaft 23 of the electric motor 20 and meshes with a toothed wheel 30 on which is located the torque output element 31. This torque output element 31 is made in the form of a shaft concentric with the toothed wheel 30, the end of which has the form of a star-shaped female socket into which an actuating rod (not shown) of a locking system is capable of coming so as to lock or unlock a toothing of the gearbox (not shown) via an actuating lever (not shown). Alternatively, the torque output element 31 can be made in the form of a male socket. This torque output element 31 is guided in rotation by a barrel 80 of the housing 10. A sealing means is positioned in this barrel 80 in order to ensure that external pollutants do not enter the interior of the actuator 1. Similarly, a sealing means is provided between the cover 14 and the housing 10 and between the cover 12 and the housing 10.

[0029] The housing 10 also comprises an electrical connector 15 for electrically connecting the internal components to the actuator 1.

[0030] Fastening means 11 in the form of metal inserts are arranged at several locations on the housing 10 in order to be able to fix it to the gearbox of the vehicle. In the present case, three inserts 11 are provided.

[0031] In [Fig.2], an X, Y, Z reference frame is illustrated. The X direction or axis corresponds to a longitudinal direction. The Y direction or axis, transverse, is defined as being perpendicular to the longitudinal direction X. More specifically, the longitudinal and transverse directions X and Y may, for example, substantially belong to a plane PI (visible in [Fig.3]) which is substantially horizontal. The Z direction or axis corresponds to a vertical direction. More specifically, the transverse and vertical directions Y and Z may, for example, substantially belong to a plane P2 (visible in [Fig.3]) which is substantially vertical.

[0032] This figure shows more precisely the integration of the electric motor 20 and the reduction mechanism 70 in the housing 10.

[0033] The brushless direct current type electric motor 20 is provided with stator coils, a rotor and an output shaft 23 connected to the rotor and extending along an axis X. The stator coils forming the stator of the electric motor are three in number.

[0034] A multi-pole magnet 21 is fixed on 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 can have a different number of poles.

[0035] The reduction mechanism 70 comprises a worm screw 22 positioned on the output shaft 23 of the electric motor 20 and meshes with a toothed wheel 30 on which the torque output element 31 is located. The torque output element 31 extends along an axis Z. The end of the output shaft 23 opposite the electric motor 20 is guided in rotation in a housing 16 of the housing and thus serves as a bearing.

[0036] The housing also receives the first electronic card 50 and the second electronic card 40.

[0037] The first electronic card 50, which is the main electronic card of the actuator, allows the electronic management of the actuator and integrates electronic components necessary 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), a sensor 52 of the angular position of the torque output element 31. The first electronic card 50 has a shape substantially 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 card 50 is fixed to the housing 10 via the openings 51 located at its periphery.

[0038] The second electronic card 40 comprises at least one device for determining the position of the rotor of the electric motor located opposite the multi-pole magnet 21 in order to provide a signal necessary for the electronic switching of the power supply to the stator coils of the electric motor 20.

[0039] [Fig. 3] shows more precisely the arrangement of the electric motor 20 and the two electronic cards 50, 40. The first electronic card 50 extends in a plane P1 substantially parallel to the X axis and the second electronic card 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 card 40 has a substantially “U” shape with one leg of the “U” larger than the other. Said larger leg is the one facing the first electronic card 50. The second electronic card 40 comprises an opening 47 through which the output shaft 23 of the electric motor 20 passes. The multi-pole magnet 21 is also located in the opening 47.

[0040] The device for determining the position of the rotor of the electric motor 20 of the second electronic card 40 comprises at least one phase sensor 41, 42, 43, located opposite the multi-pole magnet 21 in order to ensure the electronic switching of the power supply to the stator coils of the electric motor 20. More precisely, three sensors 41, 42, 43 are distributed on the second electronic card 40 concentrically to the X axis. These three sensors 41, 42, 43 thus surround the multi-pole magnet 21. These three sensors are of the Hall effect type.

[0041] The second electronic card 40 also comprises power supply pins 44, 45, 46, in order to electrically supply the stator coils of the electric motor 20. These pins 44, 45, 46 are three in number and thus make it possible to supply three stator coils of the electric motor 20. These three pins 44, 45, 46 are distributed on the second electronic card 40 concentrically to the X axis in an alternating manner with the three sensors 41, 42, 43.

[0042] [Fig.4] shows the connection between the two electronic cards 50, 40. The first electronic card 50 and the second electronic card 40 are electrically connected via an “L” shaped connection element 60.

[0043] [Fig.5] shows the actuator 1 without the cover 14 or the first electronic card 50. However, the fixing screws 18 for fixing the first electronic card 50 are visible. These fixing screws 18 pass through the openings 51 of the first electronic card 50. The first electronic card 50 rests on pins 19 of the housing 10 and the fixing screws 18 are screwed into these pins 19.

[0044] [Fig.5] also shows in detail the fixing of the second electronic card 40. This second electronic card 40 is fixed to the housing 10 by means of slides 17 coming from the housing 10. In the present case, two slides are necessary and distributed at the transverse ends of the second electronic card 40.

[0045] The housing 10 also has a cavity in which the toothed wheel 30 is housed and this cavity substantially matches the shape of the toothed wheel 30.

[0046] In this [Fig.5] is also visible the opposite end of the shaft of the torque output element 31, this end of the shaft is located opposite the angular position sensor 52 of the first electronic card 50.

[0047] Although the invention has been described in connection with a particular embodiment, it is obvious that it is in no way limited thereto and that it includes all the technical equivalents of the means described.

[0048] In the claims, any reference sign in parentheses cannot be interpreted as a limitation of the claim.

Claims

Claims

1. Actuator (1) for a parking lock system of a vehicle gearbox, said actuator (1) comprises an electric motor (20) provided with stator coils, a rotor and an output shaft (23) connected to the rotor and extending along an X axis, a reduction mechanism (70) having a torque output element (31) rotatable so as to be able to rotate between a locking position and a release position, said reduction mechanism (70) being kinetically connected to the output shaft (23) of the electric motor (20), the electric motor (20) is of the brushless direct current type and in that the actuator (1) comprises a first electronic card (50) and a second electronic card (40), said second electronic card (40) comprises a device for determining the position of the rotor of the electric motor (20),characterized in that the first electronic card (50) extends in a plane PI substantially parallel to the X axis and the second electronic card (40) extends in a plane P2 substantially perpendicular to the X axis.,

2. Actuator (1) according to claim 1, characterized in that the first electronic card (50) and the second electronic card (40) are electrically connected via an L-shaped connection element (60).

3. Actuator (1) according to one of the preceding claims, characterized in that at least one multi-pole magnet (21) is fixed on the output shaft (23) of the electric motor (20) and in that the device for determining the position of the rotor of the electric motor (20) of the second electronic card (40) comprises at least one phase sensor (41, 42, 43) located opposite the multi-pole magnet (21) in order to ensure the electronic switching of the power supply to the stator coils of the electric motor (20).

4. Actuator (1) according to one of the preceding claims, characterized in that the first electronic card (50) comprises a position sensor (52) opposite the torque output element (31) in order to determine its angular position.

5. Actuator (1) according to one of the preceding claims, characterized in that the second electronic card (40) comprises power supply pins (44, 45, 46), in order to electrically supply the stator coils of the electric motor (20).

6. Actuator (1) according to one of the preceding claims, characterized in that the second electronic card (40) comprises an opening (47) through which the output shaft (23) of the electric motor (20) passes.

7. Actuator (1) according to one of the preceding claims, characterized in that the electric motor (20), the output shaft (23) of the electric motor (20), the reduction mechanism (70), the first electronic card (50) and the second electronic card (40) are housed in a single-piece housing (10).

8. Actuator (1) according to the preceding claim, characterized in that the first electronic card (50) is fixed to the housing (10) by means of fixing screws and in that the second electronic card (40) is fixed to the housing (10) by means of at least one slide (17) coming from the housing (10).

9. Actuator (1) according to claim 7 or 8, characterized in that the housing (10) comprises an electrical connector (15) allowing the first electronic card (50) and the second electronic card (40) to be electrically connected to an external electrical power source.

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