Bearing device for electric motor and electric motor

Abstract

The utility model relates to a bearing device used for a motor, the motor comprises a motor housing and a motor shaft, the bearing device supports the motor shaft in the motor housing, and the bearing device is characterized in that the bearing device is in an integrated structure; the central hole is formed by a cylindrical inner surface, the outer surface is constructed to be a convex curved surface, and the motor shaft penetrates through the central hole in an interference fit mode, so that sliding friction is formed between the motor shaft and the inner surface in the rotating operation process of the motor shaft.

Description

Technical Field

[0001] The utility model relates to a bearing device for an electric motor and an electric motor comprising the bearing device. Background Art

[0002] In the designs of all electric motors currently on the market, the motor shaft is usually rotatably supported in the motor housing by means of metal bearings arranged at both ends of the motor housing to achieve normal forward and reverse operation.

[0003] The manufacturing process of traditional bearings is complicated, the precision of the manufacturing process is difficult to control, and the motor is prone to noise and abnormal sound during the operation under force. This design is not satisfactory for fields with high requirements for quietness, such as smart furniture, functional sofas, medical equipment, electric office desks, etc.

[0004] In addition, especially in the field of electric furniture, electric furniture can have a variety of postures, such as the sitting posture, TV posture, and lying posture of an electric sofa, and the lowering and lifting postures of an electric bed. The change process of these postures is completed by the motor drive connected to the mechanical structure. However, during the posture change process, the load force of the motor is too large, resulting in the motor often not being able to brake immediately when it stops moving. This untimely stop will bring potential safety hazards, such as users being pinched or hit, and uncontrolled accidental collisions between the movable furniture itself and obstacles, such as walls.

[0005] In order to achieve safe operation, external resistance is usually used to achieve braking, such as installing an independent brake pad on the outside of the motor shaft extending out of the motor housing end cover as a braking device. However, this design and assembly process is cumbersome and will bring additional work hours and manufacturing costs. Utility Model Content

[0006] The technical problem to be solved by the utility model is to provide an electric motor with a simple structure and safer operation.

[0007] In order to solve the above technical problems, the utility model provides a bearing device for an electric motor, wherein the electric motor comprises a motor housing and a motor shaft, wherein the motor shaft is supported in the motor housing by the bearing device, and is characterized in that the bearing device is integrally constructed and has a center hole formed by a cylindrical inner surface and an outer surface constructed as an outer convex curved surface, wherein the motor shaft passes through the center hole with an interference fit, thereby forming sliding friction between the motor shaft and the inner surface during the rotation of the motor shaft.

[0008] Compared with the motor brake pads separately provided in the prior art, the bearing device according to the utility model is always connected with the motor shaft by interference fit. During the operation of the motor shaft, the bearing device not only supports the motor shaft, but also applies an appropriate degree of braking force to the motor shaft by friction fit between the inner surface and the motor shaft, so that when the motor stops running, the motor shaft is fully and thoroughly braked in a timely and effective manner. As a result, the bearing device plays a dual role of supporting and braking the motor shaft.

[0009] It should be noted here that the braking effect of the bearing device on the motor shaft does not excessively affect the normal rotation of the motor shaft, that is, the bearing device does not lock the rotating motor shaft, but forms a certain degree of sliding friction between the two.

[0010] According to a preferred embodiment of the present invention, a plurality of grooves are constructed on the outer surface.

[0011] The outer surface of the bearing device is constructed as an outward convex arc surface, thereby forming an outward convex outer contour of the bearing device as a whole. The multiple grooves arranged on the outer surface not only reduce the weight of the bearing device and save material costs, but also improve the heat dissipation effect through a larger contact area with the external environment. This is very important for the high temperature conditions in which the motor is operated.

[0012] According to a preferred embodiment of the present invention, the plurality of grooves are evenly arranged at the same angular distance along the circumference of the outer surface of the bearing device.

[0013] Preferably, a plurality of rows of grooves are sequentially arranged on the outer surface along the axial direction of the bearing device, wherein each row of grooves comprises a plurality of grooves adjacently arranged in the circumferential direction.

[0014] Preferably, each row of grooves comprises the same number of grooves.

[0015] Preferably, two rows of grooves are arranged sequentially on the outer surface along the axial direction of the bearing device.

[0016] Preferably, the groove is recessed inward from the outer surface and forms a groove bottom, wherein a non-zero spacing exists between the groove bottom and the inner surface. That is, the plurality of grooves arranged on the outer surface are not recessed into the inner surface of the bearing device. In other words, the groove does not penetrate the outer surface and the inner surface of the bearing device in the radial direction of the bearing device, but forms a "semi-hollow" structure. This design increases the heat dissipation effect and reduces the weight of the bearing device while ensuring the necessary strength of the bearing device.

[0017] According to a preferred embodiment of the present invention, the groove has a polygonal bottom surface shape. Preferably, the groove has a rectangular bottom surface shape. Thus, the manufacturing process of the bearing device can be simplified.

[0018] According to a preferred embodiment of the present invention, the inner surface comprises at least one oil passage extending along the axial direction of the bearing device. Preferably, the inner surface comprises a plurality of oil passages uniformly arranged at the same angular distance along the circumference of the inner surface.

[0019] In order to solve the technical problem, the utility model also provides a motor, which includes a motor housing, a motor shaft and the above-mentioned bearing device. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] The embodiments of the present invention are described in detail below with reference to the accompanying drawings.

[0021] Figure 1 A cross-sectional view schematically shows a motor according to the utility model;

[0022] Figure 2 A perspective view schematically showing a bearing device for an electric motor according to a first embodiment of the present utility model;

[0023] Figure 3 Schematically shown Figure 2 a side view of the bearing arrangement shown;

[0024] Figure 4 Schematically shown Figure 2 A cross-sectional view of the bearing arrangement shown;

[0025] Figure 5 A perspective view schematically showing a bearing device for a motor according to a second embodiment of the present utility model;

[0026] Figure 6 Schematically shown Figure 5 A top view of the bearing arrangement shown;

[0027] Figure 7 A perspective view schematically showing a bearing device for an electric motor according to a third embodiment of the present utility model;

[0028] Figure 8 Schematically shown Figure 7 a side view of the bearing arrangement shown; and

[0029] Fig. 9 Schematically shown Figure 7 A top view of the bearing arrangement shown. DETAILED DESCRIPTION

[0030] The following will be combined with the drawings in the embodiments of the utility model to clearly and completely describe the technical solutions in the embodiments of the utility model. Obviously, the described embodiments are only part of the embodiments of the utility model, not all of the embodiments. Based on the embodiments in the utility model, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the utility model.

[0031] The term "one embodiment" or "embodiment" as used herein refers to a specific feature, structure or characteristic that may be included in at least one implementation of the present invention. In the description of the present invention, it should be understood that the orientation or positional relationship indicated by the terms "upper", "lower", "left", "right", "top", "bottom", etc. is based on the orientation or positional relationship shown in the accompanying drawings, which is only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation on the present invention. In addition, the terms "first" and "second" are used only for descriptive purposes, and cannot be understood as indicating or implying relative importance or implicitly indicating the number of technical features indicated. Thus, the features defined as "first" and "second" may include one or more of the features explicitly or implicitly. Moreover, the terms "first", "second", etc. are used to distinguish similar objects, and are not necessarily used to describe a specific order or sequence. It should be understood that the data used in this way can be interchanged where appropriate, so that the embodiments of the present invention described here can be implemented in an order other than those illustrated or described here.

[0032] Figure 1 The electric motor 1 according to the utility model is shown, which includes a motor housing 10, a motor shaft 20 protruding outward from a front end cover 12 of the motor housing 10, and a bearing device 40 for rotatably supporting the motor shaft 20 in the motor housing 10. The electric motor 1 can be configured as a brushed DC motor, which also includes unspecifically labeled magnetic tiles, iron cores, commutators, brush holders, etc., and its basic working principle is known and will not be described here.

[0033] The following is with the help of Figures 2 to 9 The bearing device 40 is explained.

[0034] According to a preferred embodiment, the bearing device 40 has a central hole and a convex outer surface 44, such as Figure 2 The center hole is as shown. Figure 4 The bearing device 40 is shown as being composed of a cylindrical inner surface 42 arranged around the axial direction a, and an outer surface 44 is configured as a convex curved surface similar to a sphere.

[0035] A plurality of grooves 440 are arranged on the outer surface 44, wherein the grooves 440 can be arranged in different ways. Figures 2 to 9 As shown, a plurality of grooves 440 are sequentially arranged in two rows on the outer surface 44 along the axial direction a of the bearing device 40, and each row of grooves 440 includes a plurality of grooves 440 adjacently arranged along the circumferential direction of the outer surface 44. However, in an embodiment not shown, only one row or three or more rows of grooves may also be arranged.

[0036] The grooves 440 arranged adjacent to each other along the circumference of the outer surface 44 are kept at the same distance, that is, the grooves 440 in the same row are arranged substantially evenly and dispersedly. In addition, each row of grooves 440 has the same number of grooves 440, and the grooves 440 in two adjacent rows are aligned at the same angular position. In an embodiment not shown, the grooves 440 in two adjacent rows may also be arranged with an angle offset from each other.

[0037] like Figure 4 As shown, the grooves 440 are respectively recessed inward from the outer surface 44 of the bearing device 40 until a groove bottom 442 is formed. The grooves 440 do not extend to the extent of penetrating the inner surface 42 of the bearing device 40, but the groove bottom 442 is kept at a non-zero distance d from the inner surface 42. Thus, a half-hollow structure of the bearing device 40 is formed.

[0038] The groove 440 may have various bottom shapes.

[0039] For example Figures 2 to 5 As shown, in the side view of the bearing device 40, a single groove 440 is constructed in a narrow and elongated manner and has a pentagonal bottom surface shape, wherein the groove 440 has a sharp groove edge 444 in the direction toward the end of the bearing device 40, and is constructed in a straight manner at the end of the middle section of the bearing device 40 having the largest radius.

[0040] In addition, if Figures 7 to 9 In the illustrated embodiment, in the side view of the bearing device 40, the single groove 440 is also configured to be elongated, but it has a rectangular bottom surface shape. This simpler design facilitates the manufacture of the bearing device.

[0041] Of course, in an embodiment not shown, the bottom shape of the groove 440 may also be changed as needed. For example, the groove 440 may have an elliptical bottom shape or a bottom shape of another polygon such as a triangle or a hexagon.

[0042] In another preferred embodiment, in order to reduce the wear caused by sliding friction between the bearing device 40 and the motor shaft 20 and to increase the reliability of cooling, necessary lubrication should be provided between the bearing device 40 and the motor shaft 20. To this end, the bearing device 40 may further include a plurality of oil passages 420 arranged on its inner surface 42. Figure 5 and Figure 6 As shown, three oil passages 420 are provided. However, in embodiments not shown, two, four or more oil passages may also be provided.

[0043] Multiple oil passages 420 are dispersedly arranged at uniform angular distances in the circumferential direction and extend longitudinally along the axial direction a of the bearing device 40 , wherein the oil passages 420 preferably have an arc-shaped cross-section and are recessed from the inner surface 42 of the bearing device 40 toward the outer surface 44 .

[0044] The bearing device 40 can be made of a thermoplastic material, such as polyetheretherketone (PEEK), in one piece, for example, by a casting process. As a non-rigid material, the thermoplastic material provides the bearing device with a certain elastic deformation capacity, thereby allowing the bearing device to maintain the necessary strength of the device while also being able to form sliding friction between the bearing device and the motor shaft without locking the motor shaft. Particularly preferably, the thermoplastic material is polyetheretherketone. Of course, other suitable materials can also be considered.

[0045] Different from the conventional metal powder sintering process, the bearing device 40 manufactured in one piece using thermoplastic material, especially polyetheretherketone material, has necessary elasticity. The bearing device 40 is connected to the motor shaft 20 by interference fit, that is, the outer diameter of the motor shaft 20 is designed to be slightly larger than the inner diameter of the center hole of the bearing device 40, so that when the motor shaft 20 passes through the center hole of the bearing device 40, a close contact is formed between the motor shaft 20 and the bearing device 40, wherein the bearing device 40 applies pressure to the motor shaft 20 in the radial direction.

[0046] In such Figure 1 In the motor 1 shown, the bearing device 40 is fixedly connected to the rear end cover 14 of the motor housing 10 with its outer surface 44, and is interference fit with the motor shaft 20 with its inner surface 42. When the motor shaft 20 rotates, sliding friction occurs between the motor shaft 20 and the inner surface 42 of the bearing device 40, so that the bearing device 40 exerts a dual effect of supporting and braking the motor shaft 20.

[0047] In addition, the motor 1 further comprises another bearing device 30, namely a front bearing device 30. In this embodiment, the first bearing device 30 is configured as a rolling bearing, for example, and is arranged at the front cover 12, so as to rotatably support the motor shaft 20 from the outside of the motor housing 10.

[0048] The above description has fully disclosed the specific implementation of the utility model. It should be pointed out that any changes made by technicians familiar with the field to the specific implementation of the utility model do not deviate from the scope of the claims of the utility model. Accordingly, the scope of the claims of the utility model is not limited to the above specific implementation.

Claims

1. A bearing device for an electric motor, the electric motor comprising a motor housing and a motor shaft, wherein: The motor shaft is supported in the motor housing by means of the bearing device, wherein the bearing device is integrally constructed and has a center hole formed by a cylindrical inner surface and an outer surface constructed as an outer convex curved surface, wherein the motor shaft passes through the center hole with an interference fit, thereby forming sliding friction between the motor shaft and the inner surface during the rotation of the motor shaft.

2. The bearing device according to claim 1, characterized in that: A plurality of grooves are formed on the outer surface.

3. The bearing device according to claim 2, characterized in that: The plurality of grooves are evenly arranged at the same angular distance along the circumference of the outer surface of the bearing device.

4. The bearing device according to claim 2, characterized in that: A plurality of rows of grooves are sequentially arranged on the outer surface along the axial direction of the bearing device, wherein each row of grooves comprises a plurality of grooves adjacently arranged in the circumferential direction.

5. The bearing device according to claim 4, characterized in that: Each row of grooves includes the same number of grooves.

6. The bearing device according to claim 4, characterized in that: Two rows of grooves are arranged in sequence on the outer surface along the axial direction of the bearing device.

7. The bearing device according to claim 2, characterized in that: The groove is recessed inward from the outer surface and forms a groove bottom, wherein a non-zero spacing exists between the groove bottom and the inner surface.

8. The bearing device according to claim 2, characterized in that: The groove has a polygonal bottom shape.

9. The bearing device according to claim 8, characterized in that: The groove has a rectangular bottom shape.

10. The bearing device according to claim 1, characterized in that The inner surface includes at least one oil passage extending in an axial direction of the bearing device.

11. The bearing device according to claim 10, characterized in that: The inner surface includes a plurality of oil passages uniformly arranged at the same angular distance along the circumference of the inner surface.

12. An electric motor, characterized in that: The electric motor comprises a motor housing, a motor shaft and a bearing device according to any one of claims 1 to 11.

Images