Housing for an electric drive

Abstract

Housing (21, 23) for receiving an electric drive (E) with an electric motor (30) having a drive shaft (31) with an axis of rotation (a), wherein the housing (21, 23) comprises at least one housing shell (26) with a receiving space (29) and a cover (27), wherein a motor housing (37) of the electric motor (36) with respect toaxial directions (y1, y2) of the axis of rotation is held spring-loaded between at least one end stop (47) and at least one elastically deformable spring tongue (38) of the housing (21, 23), wherein the end stop (47) provides an end face (46) and the spring tongue (38) a support surface (48) against which the motor housing (37) rests, characterized in that the spring tongue (38) has a contact surface (40) which is detachably in contact with a retaining surface (41) of a cover tongue (42) of the cover (27) having a free end region, wherein the retaining surface (41) can absorb forces of the spring tongue (38) which are directed in at least one axial direction (y1).

Description

[0001] The invention relates to a housing for an electric drive.

[0002] Such a housing is known, for example, from the apparent prior use of a headrest. The headrest includes an electric motor, housed in a casing, for horizontal or vertical adjustment of a head support element. The casing is attached to a head support element of the headrest. The motor shaft drives a multi-stage gearbox, the output spindle of which interacts with a guide system of the headrest. During an adjustment process, forces introduced by the spindle act on the motor shaft and thus on the motor housing.

[0003] To ensure the motor is mounted without play in the drive housing, it must be held between at least one stop and at least one spring tongue of the housing. The spring tongue provides spring tension in the motor's seat with respect to the axial direction of the motor shaft. To absorb the axial forces transmitted by the motor, the spring tongue had to be designed to be very robust, especially with high motor forces, which negatively impacted the spring travel.

[0004] DE 10 2006 052 958 A1 relates to an electric motor with a rotor shaft that is rotatably mounted about the axis of rotation 21 by means of two bearings 15a and 15b. The rotor shaft 20 is guided axially by the fact that its two ends 20a and 20b are in contact with sliding surfaces 31a and 31b, which are part of the housing and are therefore stationary (see paragraph 23 of DE 10 2006 052 958 A1). One end of the rotor shaft 20 contacts a wall of the housing base, and the opposite end is in contact with a tongue that is integrally formed with the housing base. According to paragraph 25, the tongue is spaced apart from the wall of the housing base, and a gap is formed between the housing base and the tongue, into which a spring element is inserted.

[0005] According to paragraph 27, the housing includes a projection 35 formed integrally with the housing cover, which serves as a stop for the tongue 32 and thus limits any possible axial displacement of the rotor axis to the left. In the Fig. In the embodiment shown in 1 to 5, the force F is generated by the spring element 40, which causes the axle ends 20a and 20b to be pressed against the sliding surfaces 31a and 31b.

[0006] WO 2013 / 091954 A2 concerns an electric machine with an axial preload between a rolling bearing and a housing part. The machine comprises a rotor shaft extending axially and rotatably mounted in a housing part by means of a rolling bearing. At least two axially arranged spring elements are supported axially against the housing part and exert an axial preload between the housing part and the rolling bearing.

[0007] In DE 10 2006 036 523 A1 it is described that spring tongues are used to connect housing parts.

[0008] WO 2015 / 197 573 A1 describes a drive unit. Here, the loading of a drive shaft 2 by means of a spring element, which is supported by the housing 10, is disclosed.

[0009] DE 43 24 912 A1 describes an actuator in which an electric motor 2 is mounted in a gearbox housing 1 between a thrust bearing 18 and a spring element 16. Fig. Figure 3, which shows the conventional mounting of the electric motor, is according to the invention of the in Fig. Figure 4 shows an elastomer buffer 9 with a pressure pin 9, wherein the spring element 16 acts only on the rotor 7 via the pressure pin 9. Accordingly, column 3, line 45 states that only the rotor 7 is brought into a defined axial position, while the stator 6 can assume different positions due to motor tolerances.

[0010] According to US 6,208,046 B1, a stator 100 with its housing 110 is firmly held to a support plate. A cover 500 of the housing has U-shaped cutouts (see Fig. 2), which connects the shaft 200 via a holder and a ball according to Fig. 2. Apply downward pressure.

[0011] The object of the invention was to create a mounting for an electric motor in the housing of the drive, wherein the motor housing of an electric motor is spring-loaded in the seat by a spring tongue in the axial direction of the motor shaft, wherein the spring tongue can absorb a large axial force and yet provide a large spring travel.

[0012] The problem was solved by a housing having the features of claim 1.

[0013] The housing serves to accommodate an electric drive comprising an electric motor with a drive shaft having an axis of rotation. The housing includes at least one housing shell with a receiving space for receiving a motor housing of the electric motor and at least one cover for closing the housing. The motor housing of the electric motor is held between at least one end stop and at least one elastically deformable spring tongue of the housing and / or the cover with respect to the axial directions of the axis of rotation. The motor housing rests against an end face of the end stop and against a support surface of the spring tongue, whereby the spring tongue and the support surface may also be located in the cover or alternately in the cover and the housing.

[0014] To secure the motor housing, two or more spring tongues and / or two or more end stops can be formed on the housing. The end stops can, for example, be formed by at least one projection extending into the receiving space of the housing. The spring tongue can, for example, be formed integrally with the housing shell.

[0015] The spring tongue has a contact surface that can be detachably attached to a holding surface of the cover and / or the housing, the holding surface being able to absorb forces of the spring tongue directed in an axial direction of the axis of rotation.

[0016] In this way, the spring tongue can absorb large axial forces without requiring a larger dimension. Furthermore, the additional support of the spring tongue, combined with a weak spring tongue design necessary for a large spring travel, allows for high axial contact forces.

[0017] The contact surface and the retaining surface are inclined, for example, to the direction of the fastening force with which the cover is held to the housing shell, such that the fastening force is redirected in an axial direction to clamp the motor housing between the end face of the housing and the support surface of the spring tongue. In other words, the contact surface and the retaining surface are inclined such that a force is redirected from the direction of the fastening force into the axial direction. The fastening force can be applied, for example, by a screw connection. With a screw connection, the fastening force can be easily and continuously adjusted.

[0018] Basically, the lid can be connected to the housing shell using any suitable connection, such as a screw connection, adhesive connection or rivet connection.

[0019] The retaining surface can, for example, be formed on a cover tongue that is held against the cover. Forces can then be transferred from the cover tongue to the cover. In this way, the spring tongue on the housing can be designed for a greater spring travel during assembly. The necessary contact force on the motor housing is achieved, for example, by supporting the spring tongues via the cover tongues. The cover tongue can, for example, be formed integrally with the cover. The number of cover tongues corresponds, for example, to the number of spring tongues.

[0020] The spring tongue and / or cover tongue is, for example, held at one end of the housing and also has a free end. The free end is designed to be elastically deformable.

[0021] For example, the housing can be fitted with two spring tongues and two cover tongues. The forces that occur are then distributed between the two pairs of spring tongues and cover tongues. Each interacting pair of spring tongue and cover tongue is subject to a lower load.

[0022] The spring tongue and / or the cover tongue is separated from the housing wall, for example, by at least one recess, such that it is only connected to the housing at a first end region, while another region, e.g., a free end region, is elastically deformable. In this way, a large spring travel of the cover tongue can be achieved, even in housings molded from plastic.

[0023] According to one embodiment, the housing shell and / or the lid shell are molded plastic parts. This ensures simple manufacturing. Furthermore, plastic has good elastic deformation properties.

[0024] Further advantages of the invention will become apparent from an embodiment shown in the figures. They show: Fig. 1 A perspective front view of a headrest with vertical and horizontal adjustment of the head support part, where a head cushion of the headrest is not shown, Fig. 2 a perspective rear view of the headrest according to Fig. 1, Fig. 3 a perspective view of a housing for an electric drive, Fig. 4. A top view of the housing, with the lid not shown for clarity. Fig. 5 a section view according to section line V - V in Fig. 4, where the lid is shown Fig. 6 a perspective view of the lid and the spindle nut, Fig. 7 a perspective view of the housing shell and the electric motor.

[0025] A headrest as a whole is designated by reference numeral 10 in the drawings. The same reference numerals in the different figures denote corresponding parts, even if lowercase letters are added or omitted.

[0026] The headrest includes, according to Fig. 1. A base part 11, which is adjustable in directions z1 and z2, is mounted on support rods 13a and 13b of a support rod bracket 12. The support rods 13a and 13b are connected to each other by a crossbeam 14. When moving in directions z1 and z2, the base part 11 is displaced relative to the support rod bracket 12. The headrest 10 has a vertical drive 15 for this displacement in directions z1 and z2.

[0027] Furthermore, the headrest 10 includes a head support 17, which is adjustable in directions x1 and x2 and mounted on the base part 11. The head support 17 is located in the Fig. 1 and Fig. Only guides 18a and 18b are shown. A head mounting plate, for example, is not shown. The head mounting 17 can be moved in the directions x1 and x2 relative to the base part 11 by means of a horizontal drive 16.

[0028] Both support rods 13a and 13b are designed as tubes. For control and power supply of the vertical drive 15 and the horizontal drive 16, a multi-core cable 19 is routed through a receiving space of the support rod 13a and connected to the vertical drive 15 and the horizontal drive 16.

[0029] In Fig. Figure 1 shows a spindle 20, which is part of the vertical drive 15. A thread 22 of the spindle 20 is connected to a thread of a Fig. 1. A spindle nut (not shown) engages with the spindle nut, which is rotatably mounted in a housing 21 and is part of a gearbox that can be driven by an electric drive with an electric motor located in the housing 21. Depending on the direction of rotation of the spindle nut, the base part 11, which is fixedly connected to the housing 21, is moved in the direction z1 or in the direction z2.

[0030] In Fig. A housing 23 corresponding to housing 21 is visible and is attached to the base part 11. Like housing 21, housing 23 also contains an electric drive with an electric motor. A thread of the spindle nut contained in housing 23 engages with a thread 24 of a spindle 25. The spindle 25 is fixedly connected to the head assembly 17. Depending on the direction of rotation of the spindle nut, the head assembly 17 is moved in direction x1 or in direction x2 relative to the base part 11 and the support bracket 12.

[0031] In Fig. Figure 3 shows the housing 21 and the spindle 20 of the vertical drive 15. The following description of the vertical drive 15 also applies in the same way to the housing 23 and the spindle 25 of the horizontal drive 16, because the vertical drive 15 and the horizontal drive 16 have the same construction.

[0032] The housing 21 comprises a housing shell 26 and a cover 27, which is held to the housing shell 26 by several fastenings 28 in the form of a screw connection 49. The screw connections 49 are indicated by dashed lines in Fig. 3 indicated. The spindle 20 passes through openings in the housing 21. In Fig. Figure 4 shows a top view of a receiving chamber 29 of the housing 21. An electric motor 30 is fixedly arranged in the receiving chamber 29 of the housing 21. The electric motor 30 comprises a drive shaft 31, which can be driven in two opposite directions of rotation. A worm gear 32 is mounted on the drive shaft 31 and is rotatably connected to the drive shaft 31.

[0033] The worm gear 32 engages with the external teeth 33 of a spindle nut 34 and drives the spindle nut 34 in the directions u1 or u2, depending on the direction of rotation of the electric motor 30. An internal thread 35 of the spindle nut 34 engages with the thread 22 of the spindle 20. The engagement of the internal thread 35 with the thread 22, as well as the engagement of the worm gear 32 with the external teeth 33 of the spindle nut 34, forms a gearbox 36 between the spindle nut 34 and the spindle 20. Forces are transmitted from the worm gear in the axial direction y1 or y2 of the drive shaft 31. These forces are then transmitted to a motor housing 37 of the electric motor 30.

[0034] The motor housing 37 is according to Fig. 4 with respect to the axial directions y1 and y2 of the drive shaft 31 between end faces 46, which are formed on end stops 47, and support surfaces 48 of the spring tongues 38. In the present embodiment, the end stops 47 are formed by three projections extending into the receiving space 21. Only two of the end stops 47 are in Fig. 4. The spring tongues 38 are deflected in the direction of y1 when the motor housing 37 is in its seat in the receiving chamber 29 of the housing 21. In this way, the electric motor 30 is held rattle-free in the housing 21.

[0035] In the present embodiment, two spring tongues 38 are formed on the housing shell 26. As e.g. in Fig. 3 and Fig. As can be seen in Figure 4, the spring tongues 38 are cut free from a housing wall 45 on both sides by recesses 43 and a recess 44. In this way, the spring tongues 38 can be elastically deformed in the direction y1 and, after deformation in direction y1, return to their initial position in direction y2 due to their restoring force.

[0036] Since considerable axial forces can act on the drive shaft 31 depending on the engine load, the spring tongues 38 must be able to absorb these forces. A free end region 39 of the spring tongue 38 is provided with a contact surface 40. With the housing 21 closed (see Fig.5) The contact surface 40 rests against a retaining surface 41 of the cover 27. In the present embodiment, the retaining surface 41 is assigned to a free end region 50 of a cover tongue 42 of the cover 27, which can also be elastically deformed in the direction y1 and moves back in the direction y2 due to its restoring force when the force in the direction y1 decreases.

[0037] The cover 27 absorbs the forces transmitted to the cover tongue 42 and transfers them via the fastenings 28 to the housing shell 26. In this way, even with large axial forces acting on the drive shaft 31, no increased dimensioning of the spring tongues 38 is necessary.

[0038] The force with which the housing of the electric motor 30 is clamped in its seat can be adjusted in the following way: The contact surface 40 and the retaining surface 41 are inclined to the axial direction such that the fastening forces acting in directions z1 and z2 are redirected into the axial direction y2 by means of the fasteners 28 in the form of screws 49. This results in a preload force acting on the motor housing in the y2 direction. By adjusting the retaining surface 41, this force can be adapted to the system so that increasing the tension of the screws 49 increases the force acting on the spring tongue 38 in the y2 direction. This clamps the motor housing 37 more tightly between the support surface 48 of the spring tongues 38 and the end faces 46 of the end stops 47. When the screws 49 are loosened, the force transmitted by the spring tongues 38 to the motor housing decreases. The spring travel of the spring tongues 38 can also be adjusted in this way by means of the screws 49.

Claims

[1] Housing (21, 23) for receiving an electric drive (E) with an electric motor (30) having a drive shaft (31) with an axis of rotation (a), wherein the housing (21, 23) comprises at least one housing shell (26) with a receiving space (29) and a cover (27), wherein a motor housing (37) of the electric motor (36) is spring-loaded with respect to axial directions (y1, y2) of the axis of rotation between at least one end stop (47) and at least one elastically deformable spring tongue (38) of the housing (21, 23), wherein the end stop (47) provides an end face (46) and the spring tongue (38) a support surface (48) against which the motor housing (37) rests, characterized by, that the spring tongue (38) has a contact surface (40) which is detachably attached to a retaining surface (41) of a lid tongue (42) of the lid (27) which has a free end region, wherein the retaining surface (41) can absorb forces of the spring tongue (38) which are directed in at least one axial direction (y1). [2] Housing (21, 23) according to claim 1, characterized by , that the contact surface (40) and the holding surface (41) are inclined to the direction (z1, z2) of a fastening force with which the cover (27) is held on the housing shell (26) such that the fastening force is redirected in an axial direction (y2) in order to clamp the motor housing (37) with an adjustable force between the end face (46) and the support surface (48). [3] Housing (21, 23) according to any one of the preceding claims, characterized by, that the cover (27) is connected to the housing shell (26) by a fastening (28), such as a screw connection (49), adhesive connection or rivet connection. [4] Housing (21, 23) according to any one of the preceding claims, characterized by , that the spring tongue (38) is formed in one piece with the housing shell (26). [5] Housing (21, 23) according to any one of the preceding claims, characterized by , that the holding surface (41) is formed on a lid tongue (42) which is held on the lid (27), wherein forces can be transferred from the lid tongue (42) to the lid (27). [6] Housing (21, 23) according to claim 5, characterized by , that the lid tongue (42) is formed in one piece with the lid (27). [7] Housing (21, 23) according to one of claims 5 or 6, characterized by , that at least two spring tongues (38) and at least two cover tongues (42) are provided. [8] Housing (21, 23) according to any one of claims 5 to 7, characterized by, that at least one spring tongue (38) and / or at least one cover tongue (42) is separated from the housing wall (45) by at least one recess (43, 44) such that it is connected to the housing (21, 23) only at a first end region, while a free end region (39) is elastically deformable. [9] Housing (21, 23) according to any one of the preceding claims, characterized by , that the housing shell (26) and the lid (27) are plastic molded parts. [10] Housing (21, 23) according to any one of the preceding claims, characterized by , that the electric drive (E) additionally includes a gearbox (36).

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