Actuator for a parking lock system of a 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 an electric motor (20) and a gear power transmission system (60) kinematically connected to the electric motor (20) are attached, wherein the actuator (1) further comprises a torque output element (70) that meshes with the gear power transmission system (60) and is rotatably movable between a locking position and an unlocking position, and the intermediate support member (10) and the torque output element (70) are provided in a housing (30), the torque output element (70) being rotatably guided by the housing (30).

Description

Description Title of the invention: Actuator for a parking lock system of a vehicle transmission [1] 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". [2] 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. [3] Actuators of this type are known and are conventionally designed with a gear system of toothed wheel and worm gear to transmit rotational motion from an electric motor to a torque output element of the actuator. [4] Document US 2019136974 A1 has the disadvantage of not using the same reference frame between the electric motor 20 and the toothed wheel 31 because the motor is carried by the housing 10 of the actuator and the toothed wheel is guided in rotation by the intermediate plate 50. This change of reference frame can lead to premature wear of the toothed wheel and worm gear system. [5] Document DE 102019100300 A1 has the disadvantage of not taking the housing into account in the calculation of tolerances, which can lead to positioning defects of the housing with the torque output element 2 when it is mounted on the transmission box. [6] In order to minimize the wear of a worm and wheel gear system, it is necessary to have good precision in the center distance between the worm and the toothed wheel. For this, it is necessary to position the motor very precisely electric motor and its worm screw relative to the gear wheel. It is also necessary to position and maintain the electric motor very precisely axially, that is to say along an axis passing through its output shaft. [7] Another associated constraint imposes good precision between the torque output element and the transmission box on which the actuator is mounted in order to respect the tolerances required by the transmission box manufacturer. To do this, it is necessary to position the torque output element very precisely in relation to the actuator housing which is itself mounted on the transmission box. [8] To summarize, it is necessary that the worm screw and the toothed wheel have the same reference frame and that the torque output element and the housing also have the same reference frame. [9] Thus, the invention provides an actuator for a parking lock system of a vehicle transmission, said actuator comprises an intermediate support on which are fixed an electric motor and a gear power transmission system in kinematic connection with the electric motor, said actuator further comprises a torque output element meshing with the gear power transmission system and rotatable between a locking position and an unlocking position, the intermediate support and the torque output element are housed in a housing and the torque output element is guided in rotation by the housing.

[0010] This arrangement thus allows the electric motor and the geared power transmission system to have the same reference frame, i.e. the intermediate support, in the same way that the torque output element and the housing have the same reference frame, i.e. the housing.

[0011] The electric motor is thus self-supported by the intermediate support. In other words, the electric motor is carried exclusively by the intermediate support.

[0012] An intermediate support is understood to mean an element of the actuator which is separate from the housing and the cover. This support is called intermediate because it is inserted between the housing and the cover.

[0013] The torque output element can be guided in rotation directly by the housing, or indirectly by means of bearings.

[0014] Another advantage of this architecture is simplified assembly. The intermediate support, electric motor, and geared power transmission system form a subassembly that is easily integrated into the housing, eliminating the need to handle components on an assembly line.

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

[0016] According to a feature of the invention, the end of the output shaft of the electric motor is guided in rotation by the intermediate support. In other words, the intermediate support forms a guide bearing for the end of the output shaft of the electric motor. The intermediate support thus prevents the output shaft of the motor from bending due to the forces associated with the gear power transmission system.

[0017] Advantageously, 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 a compression plate fixed to the intermediate support. Advantageously, the compression plate is metallic. The compression plate is preferably U-shaped. This compression plate makes it possible to hold the electric motor axially against the intermediate support. This compression plate also makes it possible to absorb the significant forces and shocks coming from the locking system, in particular by ratchet effect or "ratcheting" in English.

[0018] According to the invention, the electric motor is locked in rotation relative to the intermediate support by means of a lug originating from the intermediate support and cooperating with a notch in the electric motor.

[0019] According to an additional characteristic of the invention, the toothed wheel system is mounted to move in rotation on a shaft, said shaft being mounted on the one hand in the intermediate support and on the other hand in the housing.

[0020] According to the invention, the torque output element comprises a toothed sector meshing with the gear power transmission system.

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

[0022] According to the invention, the intermediate support has a first face on which the gear power transmission system is mounted, located opposite the housing, and a second face located opposite an electronic card.

[0023] According to another characteristic of the invention, the torque output element passes through the intermediate support and has at its end opposite the torque output a magnetic target facing a sensor mounted on the electronic card. More precisely, the intermediate support has an opening allowing the torque output element to pass from its first face to its second face. The intermediate support does not participate in the rotational guidance of the torque output element; there is radial clearance between the intermediate support and the torque output element.

[0024] Other characteristics and advantages of the invention will emerge from the following reading of a detailed example of embodiment, with reference to the appended figures:

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

[0026] [Figure 2] shows a top perspective view of the actuator of [Figure 3] without the cover;

[0027] [Figure 3] shows a bottom perspective view of the actuator of [Figure 4] without the housing;

[0028] [Figure 4] represents a sectional view AA of the actuator of [Figure 2].

[0029] It should be noted that the figures disclose the invention in sufficient detail 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.

[0030] Referring to [Figure 1] to [Figure 4], 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 waterproof fastening, for example screwing, gluing or by laser welding, ultrasonic welding. 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.

[0031] 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.

[0032] The torque output element 70 is made 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 may be made 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.

[0033] 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 gearbox, for example here an O-ring.

[0034] The intermediate support 10 supports the electric motor 20 and the gear power transmission system 60 in order to ensure precise assembly tolerances between these two elements. The intermediate support 10 thus guides the gear power transmission system 60 in rotation. 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 subassembly that can be easily integrated into the housing 30.

[0035] The gear power transmission system 60 is a system of a toothed wheel 61 and a worm screw 21. The worm screw 21 is located on an 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 made of the same material as the intermediate support 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 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 support intermediate 10. The compression plate 23 is a metal strip with elastic properties. The rear face 20b of the electric motor is housed in an opening 24 of the compression plate 23 by form complementarity. The compression plate 23 is fixed to the intermediate support 10 by fixing means, in particular two screws, located on either 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 a fixing means, in particular a screw, located near the rear face 20b of the electric motor. The compression plate also comprises two ears 25 bearing on the rear face 20b of the electric motor 20. These two ears 25 are located on the periphery of the opening 24 and are diametrically opposed.

[0037] The electric motor 20 is locked in rotation relative to the intermediate support 10 by means of a lug 12 originating from the intermediate support 10 and cooperating with a notch 22 of 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 originating from the same material as the intermediate support 10.

[0038] The toothed wheel 61 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 slidably mounted in the barrel 35 of the housing. The gear wheel 61 is double-stage, the first stage 62 of the gear wheel 61 meshes with the worm 21 of the output shaft of the electric motor 20 and the second stage 63 of the gear wheel 61 meshes with the toothed sector 71 of the torque output element 70.

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

[0040] [Figure 5] shows more precisely the assembly of the elements in the housing 30. It is thus visible that the intermediate support 10 is fixed to the housing by fixing means, in particular screws. An area of ​​the intermediate support 10 partially covers the output shaft of the electric motor, this same area of ​​the intermediate support 10 includes the guide bearing 13 for rotation of the output shaft of the electric motor 20.

[0041] Ribs originating from the guide barrel 14 are located on the second face 10b of the intermediate support and make it possible to stiffen the intermediate support 10.

[0042] The cover 40 comprises an electrical connector for connecting the actuator to an electrical source of the vehicle. The electronic card 50 is located between the intermediate support 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.

[0043] [Figure 3] shows more precisely the arrangement of the gear power transmission system 60 cooperating with the toothed sector 71 of the torque output element 70. In operation the worm 21 of the shaft of the electric motor 20 meshes with the toothed wheel 61 via its first stage 62, then the torque is transmitted to the toothed sector 71 of the torque output element 70 via the second stage 63 of the toothed wheel 61.

[0044] [Figure 4] makes it possible to highlight the recovery of the angular position of the torque output element 70. The torque output element 70 has at the opposite end of the socket 73 a magnetic target 72 facing a sensor 51 mounted on the electronic card 50. The magnetic target 72 is glued, snapped or screwed to the torque output element. The torque output element 72 passes through the intermediate support 10 on either side from the first face 10b to the second face 10b of the intermediate support via an opening 15. The intermediate support 10 does not participate in the rotational guidance of the torque output element 72, there is a radial clearance between the intermediate support 10 and the torque output element 72.

[0045] 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 technical equivalents of the means described.

[0046] In the claims, reference symbols in parentheses are not to be construed as a limitation of the claim.

Claims

Claims

1. Actuator (1) for a parking lock system of a vehicle transmission, said actuator (1) comprises an intermediate support (10) on which are fixed an electric motor (20) and a gear power transmission system (60) in kinematic connection with 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 characterized in that the intermediate support (10) and the torque output element (70) are housed in a housing (30) and the torque output element (70) is guided in rotation by the housing (30).

2. Actuator (1) according to claim 1, characterized in that the gear power transmission system (60) is a system of toothed wheel (61) and worm screw (21), said worm screw (21) is located on an output shaft of the electric motor (20).

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

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 a compression plate (23) fixed to the intermediate support (10).

5. Actuator (1) according to one of the preceding claims, characterized in that the electric motor (20) is locked in rotation relative to the intermediate support (10) by means of a lug (12) originating from the intermediate support (10) and cooperating with a notch (22) of the electric motor (20).

6. Actuator (1) according to one of claims 2 to 5, characterized in that the toothed wheel (61) is mounted to be movable in rotation on a shaft (31), said shaft (31) being mounted on the one hand in the intermediate support (10) and on the other hand in the housing (30).

7. Actuator (1) according to one of the preceding claims, characterized in that the torque output element (70) comprises a toothed sector (71) meshing with the gear power transmission system (60).

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

9. Actuator (1) according to one of the preceding claims, characterized in that the intermediate support (10) has a first face (10a) on which the gear power transmission system (60) is mounted, located opposite the housing (30) and a second face (10b) located opposite an electronic card (50).

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

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