Electric motor-gearbox assembly

Abstract

An electric motor-gearbox assembly comprises an electric motor, a gearbox, and a housing for the electric motor and gearbox. The stator of the electric motor is mounted in a motor carrier, which is constructed in two parts: a first and a second motor carrier section. These sections are axially sequential along the motor's longitudinal axis and each has a bearing point for supporting the motor shaft.

Description

[0001] The invention relates to an electric motor-gearbox assembly comprising an electric motor, a gearbox and a housing for receiving the electric motor and the gearbox. State of the art

[0002] Parking brakes are a well-known device for securing vehicles when stationary. A parking brake comprises an electric motor and a self-locking gearbox, whereby the rotational movement of the motor shaft is converted via the gearbox into a braking force-generating movement with increased torque. Due to the self-locking mechanism, the position of the gearbox components does not change even after the driving electric motor is switched off.

[0003] An electric parking brake for a motor vehicle with a drive motor and a gearbox is described, for example, in DE 103 40 250 B4. The gearbox is mounted on a mounting plate, which also has a bearing mount for the motor shaft of the electric motor. Disclosure of the invention

[0004] The electric motor-gearbox assembly according to the invention can be used as a drive unit, particularly in vehicles, preferably to drive a component that is not part of the vehicle's drivetrain, for example, a parking brake or, optionally, other components such as those used for opening and closing vehicle windows. The electric motor-gearbox assembly comprises a housing in which one or more, optionally all, components of the gearbox are accommodated. The housing can also be used to accommodate the electric motor, which is either inserted into the housing or attached to it. The electric motor is preferably a brushless, electronically commutated, permanent magnet DC motor.

[0005] The stator of the electric motor is mounted in a motor carrier, which is separate from the housing and fixed within the housing of the electric motor-gearbox assembly. The motor carrier is a two-part structure, comprising a first and a second motor carrier section. These sections, arranged axially along the motor's longitudinal axis, enclose the stator and each incorporates a bearing point for supporting the motor shaft.

[0006] This design has the advantage that the electric motor can be held and secured in the housing solely by the motor mount, with the motor shaft also requiring no additional bearing within the housing, as it is supported exclusively by the motor mount. The electric motor, along with the motor mount, can be inserted into the housing as a pre-assembled unit and secured within the housing. Inside the housing, the motor mount can also be used to secure gearbox components, such as an output gear. The motor mount thus serves two functions: firstly, to accommodate the stator, support the motor shaft, and firmly anchor all components of the electric motor within the housing; and secondly, by mounting the electric motor and motor mount within the housing, additional components, particularly gearbox components, can be secured to the motor mount.

[0007] The first and second motor support parts, which together form the motor mount, can be slid onto the stator of the electric motor from opposite axial sides during assembly. Advantageously, the two motor support parts are fastened to each other in the assembled state, which can be achieved by positive locking, material locking, and / or friction locking, for example, by a slotted connection or by welding, such as friction welding. Due to the connection of the two motor support parts, the stator, including the rotor and motor shaft, is fixed in all directions after installation and fastening in the housing.

[0008] The two motor support parts are advantageously made of a plastic material. Other materials are also suitable, particularly non-magnetizable metals or ceramics. When made of plastic, friction welding can be used to join the two motor support parts.

[0009] In an advantageous embodiment, each motor support component is fastened within the housing. Accordingly, each motor support component has one or more fastening points or attachment locations through which it is secured to the housing. Fastening to the housing preferably occurs directly through contact with the housing, for example by screwing, or indirectly by using another component located within the housing to fasten a motor support component.

[0010] In a further advantageous embodiment, a motor carrier part has contact pins for connecting stator windings in the stator. In particular, three contact pins are provided, which are connected to stator windings and which, on the side facing away from the stator, are in contact with a circuit board through which the windings are energized. The contact pins are, in particular, firmly embedded in the motor carrier part. For example, it may be advantageous for the contact pins to be firmly enclosed by a plastic material of the motor carrier part, for instance by embedding the contact pins in the injection-molded material during the injection molding of the motor carrier part.

[0011] The bearing points located in the motor support components are designed, for example, as individual bearing bushings embedded in the material of each support component. The bearing bushing can be overmolded with the material of the support component during the injection molding process, similar to how contact pins are molded. The bearing bushings are firmly integrated into each support component and allow the rotational movement of the motor shaft. In particular, the motor shaft is rotatably mounted exclusively in the bearing points within the support components, thus eliminating the need for an additional bearing point in the housing of the electric motor-gearbox assembly.

[0012] According to a further advantageous embodiment, a motor support part has a laterally projecting mounting eye which, in the assembled state, lies coaxially with a mounting recess in the housing, which serves to receive a transmission component. The mounting eye can be placed on a pin, which is in particular part of a transmission component, for example, an axle journal of a transmission component. In this way, the transmission component is fixed in the housing by the motor support part. Alternatively, it is also possible for the mounting eye to engage a housing-side boss.

[0013] According to yet another advantageous embodiment, the motor shaft of the electric motor is arranged parallel to a transmission shaft of the gearbox and meshes with the transmission shaft, which is rotatably mounted in the housing. The transmission shaft is located, in particular, in the bottom region of the trough-shaped housing, whereas the electric motor is situated at a greater distance from the bottom of the housing and thus above the transmission shaft within the housing.

[0014] Further advantages and practical designs can be found in the additional requirements, the figure description, and the drawings. These show: Fig. 1 A perspective view of a housing of an electric motor-gearbox assembly, which is exemplified by an electric parking brake actuator for use in a vehicle, Fig. 2 the electric motor-gearbox assembly in exploded view, Fig. 3 a perspective view of the electric motor-gearbox assembly in the assembled state, Fig. 4 the electric motor, mounted in a motor bracket, Fig. 5 The electric motor and the two-part motor mount in exploded view, Fig. 6 A schematic representation in side view of the electric motor-gearbox assembly.

[0015] In the figures, identical components are labelled with the same reference symbols.

[0016] The electric motor-gearbox assembly 1 shown in the figures is, in particular, an electric parking brake actuator for use in a vehicle. The electric motor-gearbox assembly 1 comprises an electric motor 2, which is preferably designed as an electronically commutated, permanent magnet DC motor, a gearbox 3 driven by the electric motor 2, and a housing with a housing part 4a and a cover 4b for receiving the electric motor 2 and gearbox 3. A printed circuit board 5 is also a component of the electric motor-gearbox assembly 1. Fig. 2) for controlling the electric motor 2.

[0017] The gearbox 3 is designed as a worm gear, driven by a gear 7 on the motor shaft 6. The gearbox 3 comprises a gearbox shaft 8, which carries a gear 8a on one end face. This gear engages with the gear 7 on the motor shaft 6. The gearbox shaft 8 has an additional threaded section 8b, which is axially spaced from the gear 8a and engages with a worm gear 9, which is rotatably mounted in the housing part 4a. The worm gear 9 constitutes the output-side gearbox component. The worm gear 9 has a pivot 10, which engages in a mounting recess 11 ( Fig. 2) is inserted and rotatably received in the mounting recess 11, which is located in the base of the receiving housing part 4a.

[0018] The transmission shaft 8 is rotatably mounted in the housing part 4a and is located adjacent to the base of the housing part 4a. In the assembled state, the electric motor 2 is positioned above the transmission shaft 8 such that the longitudinal axis of the motor shaft 6 is parallel to and offset from the longitudinal axis of the transmission shaft 8. This is shown, for example, in the illustration according to the Fig. 2, Fig. 3 and Fig. 6 can be seen, in which it can be seen that the gear 8a of the transmission shaft 8 is laterally offset and is located below the gear 7 on the motor shaft 6.

[0019] The electric motor 2 is mounted in a motor carrier 14, which, as Fig. As can be seen from Figure 5, the motor support 14 is constructed in two parts and consists of a first motor support part 15 and a second motor support part 16. The two motor support parts 15 and 16 accommodate the stator 12 of the electric motor 2 and are arranged axially one behind the other with respect to the motor's longitudinal axis, and optionally overlap axially. The two motor support parts 15 and 16 are connected to each other, either by a positive-locking connection using snap-fit ​​elements or by welding, particularly friction welding in the case of a plastic version. The motor support 14 with the two motor support parts 15 and 16 serves to accommodate the electric motor 2 and to securely fix it in the receiving housing part 4a. The motor shaft 6 is also supported by the motor support parts 15 and 16.For this purpose, bearing bushings 17 and 18 are each inserted into one of the motor support parts 15, 16, which are preferably made of metal and embedded in the motor support parts made of plastic. The bearing bushings 17, 18 are, for example, overmolded with the plastic material during the manufacture of the motor support parts 15, 16.

[0020] The first motor carrier part 15 incorporates three contact pins 19, 20, and 21, which, like the bearing bushings 17 and 18, are embedded during the manufacturing process of the motor carrier part and overmolded with the plastic material. The contact pins 19, 20, and 21 connect stator windings to associated power electronics on the circuit board 5.

[0021] Each motor support part 15, 16 is fixed in the receiving housing part 4a via one or more fastening points. The first motor support part 15 is provided with a laterally projecting fastening eye 22, which, in the assembled state, lies coaxially with the fastening recess 11 in the housing part 4a that receives the worm gear 9. The fastening eye 22 rests on the upwardly projecting section of the axle journal 10 of the worm gear 9 and thus also fixes the worm gear 9 in the housing.

[0022] The second motor support part 16 has two fastening sections 23 and 24, via which the motor support part 16 can be screwed into the housing part 4a. The first fastening section 23 extends axially on the side facing away from the other motor support part 15, the second fastening section 24 extends radially on the motor support part 16.

[0023] During the assembly of the electric motor-gearbox unit 1, the gearbox 3, including the gearbox shaft 8 and the worm gear 9, is first inserted into the housing part 4a. The motor mount 14 and the electric motor 2 are assembled outside the housing. In the manufacturing process, the plastic motor mount parts 15 and 16 are first produced by injection molding or other casting methods. During this process, the bearing bushings 17 and 18, as well as the contact pins 19, 20, and 21, are embedded in the plastic material of the motor mount parts 15 and 16. The motor mount parts 15 and 16 are then assembled with the components of the electric motor 2. The stator 12 is pressed axially into the first motor mount part 15, thereby bringing the contact pins 19, 20, and 21 into electrical contact with the stator windings.The rotor 13, with its motor shaft 6, is then axially inserted into the bearing bushing 17 in the first motor support part 15. The second motor support part 16 is axially slid onto the stator 12 from the opposite side and connected to the first motor support part 15 by suitable means, for example, by positive locking or by a friction or weld connection. A sensor magnet 25 is attached to the end face of the motor shaft 6 that faces the first motor support part 15.

[0024] After assembly of motor mount 14 and electric motor 2, this assembly is inserted into housing part 4a and secured there. This securing is achieved by screwing and / or by hot gas fusing between the plastic material of the motor mount parts 15, 16 and the plastic material of the receiving housing part 4a.

[0025] After inserting the electric motor 2 into the housing part 4a, the circuit board 5 ( Fig. 2) placed on top and the free ends of contact pins 19, 20, 21 are connected to the circuit board 5. Finally, the cover 4b ( Fig. 6) is attached and connected to the housing part 4a by suitable means, for example by laser welding, screwing or by a snap connection. QUOTES INCLUDED IN THE DESCRIPTION

[0000] This list of documents cited by the applicant was automatically generated and is included solely for the reader's convenience. The list is not part of the German patent or utility model application. The DPMA accepts no liability for any errors or omissions. Cited patent literature

[0000] DE 103 40 250 B4

[0003]

Claims

[1] Electric motor-gearbox assembly, comprising an electric motor (2), a gearbox (3) and a housing (4a) for receiving the electric motor (2) and the gearbox (3), characterized by , that the stator (12) of the electric motor (2) is received in a motor carrier (14) which is fixed (1) in the housing (4a) of the electric motor-gearbox assembly, wherein the motor carrier (14) is constructed in two parts and comprises a first motor carrier part (15) and a second motor carrier part (16), which axially successively receive the stator (12) with respect to the longitudinal axis of the motor and are each provided with a bearing point (17, 18) for supporting the motor shaft (6). [2] Electric motor-gearbox assembly according to claim 1, characterized by , that the motor carrier (14) fixes a gearbox component (9) in the housing (4a). [3] Electric motor-gearbox assembly according to claim 1 or 2, characterized by, that the two motor support parts (15, 16) are positively, materially or force-fitted to each other in the assembled state. [4] Electric motor-gearbox assembly according to one of claims 1 to 3, characterized by , that each motor support part (15, 16) is attached in the housing (4a). [5] Electric motor-gearbox assembly according to any one of claims 1 to 4, characterized by , that a motor carrier part (15) accommodates contact pins (19, 20, 21) for contacting stator windings. [6] Electric motor-gearbox assembly according to any one of claims 1 to 5, characterized by , that a motor support part (15) has a laterally projecting mounting eye (22) which, in the assembled state, lies coaxially to a mounting recess (11) in the housing (4a) for receiving a gearbox component (9). [7] Electric motor-gearbox assembly according to claim 6, characterized by, that the fastening eye (22) engages an axle pin (10) of a transmission component (9). [8] Electric motor-gearbox assembly according to any one of claims 1 to 7, characterized by , that a bearing bushing (17, 18) is received in each of the bearing points in the motor support parts (15, 16). [9] Electric motor-gearbox assembly according to any one of claims 1 to 8, characterized by , that the motor shaft (6) is arranged parallel to a transmission shaft (8) of the transmission (3) and meshes with the transmission shaft (8) which is rotatably mounted in the housing (4a). [10] Electric motor-gearbox assembly according to any one of claims 1 to 9, characterized by , that the transmission (3) is designed as a worm gear. [11] Electric motor-gearbox assembly according to any one of claims 1 to 10, characterized by a version as an electric parking brake actuator for use in a vehicle.

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