Hub motor sealing structure

Abstract

The utility model provides a wheel hub motor sealing structure which comprises a motor shell and a main shaft, the head and the tail of the main shaft extend out of the motor shell, a first shaft hole allowing the head of the main shaft to penetrate through is formed in the motor shell, a first bearing is arranged in the first shaft hole, and a second bearing is arranged in the first shaft hole. A first oil seal is arranged between the first shaft hole and the main shaft, the first oil seal comprises a first sealing part arranged between the step surface of the first shaft hole and the end surface of the outer ring of the first bearing, the inner side of the first sealing part extends inwards to form a connecting part, and a second sealing part is arranged on the inner side of the connecting part; and the inner wall of the second sealing part is provided with a sealing lip which is in contact with the outer wall of the main shaft and realizes radial sealing. The hub motor sealing structure is compact in structure, small in axial installation space, good in sealing performance, high in reliability and long in service life.

Description

Technical Field

[0001] The utility model relates to a motor, in particular to a sealing structure of a hub motor. Background Art

[0002] An electric assist bicycle is composed of adding a set of drive motors to an ordinary bicycle. The drive motors are powered by a storage battery, and the rotation of the drive motors drives the electric assist bicycle to move forward. The drive motors are generally arranged in the front hub or the rear hub, so it is also called a hub motor. The hub motor technology is also called in-wheel motor technology. Its biggest feature is that it integrates the power, transmission and braking devices into the hub, thus greatly simplifying the mechanical part of the electric vehicle. The hub motor drive system is mainly divided into two structural forms according to the rotor type of the motor: the inner rotor type and the outer rotor type. Among them, the outer rotor type adopts a low-speed outer rotor motor, and the maximum speed of the motor is 1000 - 1500 r / min, without a reduction device, and the rotation speed of the wheel is the same as that of the motor; while the inner rotor type adopts a high-speed inner rotor motor, equipped with a reducer with a fixed transmission ratio. To obtain a higher power density, the rotation speed of the motor can be as high as 10000 r / min. With the emergence of a more compact planetary gear reducer, the inner rotor type hub motor is more competitive than the low-speed outer rotor type in terms of power density.

[0003] Affected by the sealing structure, the existing hub motor will increase the axial installation dimension of the motor, that is, increase the axial thickness of the motor. Content of the Utility Model

[0004] Technical Problem to be Solved

[0005] The technical problem to be solved by the utility model is to provide a sealing structure of a hub motor with a compact structure, a small axial installation distance and a good sealing effect.

[0006] Technical Solution for Solving the Problem

[0007] The utility model provides a sealing structure of a hub motor, which includes a motor housing 1 and a main shaft 3 rotatably installed in the motor housing 1. The head and the tail of the main shaft 3 both extend outside the motor housing 1. A first shaft hole 10 for the head of the main shaft 3 to pass through is opened on the motor housing 1. A first bearing 12 is arranged in the first shaft hole 10. A first oil seal 4 is arranged between the first shaft hole 10 and the main shaft 3. The first oil seal 4 includes a first sealing part 41 arranged between the stepped surface of the first shaft hole 10 and the end face of the outer ring of the first bearing 12. The inner side of the first sealing part 41 extends inward to form a connecting part 42. A second sealing part 43 is arranged on the inner side of the connecting part 42. A sealing lip for contacting the outer wall of the main shaft 3 to achieve radial sealing is arranged on the inner wall of the second sealing part 43.

[0008] Further, an elastic member 44 that causes the sealing lip to have a radially inward movement tendency is sleeved outside the second sealing portion 43.

[0009] Further, the elastic member 44 is a spring.

[0010] Further, the first sealing portion 41 has a first sealing surface that fits against the stepped surface of the first shaft hole 10 and a second sealing surface that fits against the outer ring end surface of the first bearing 12.

[0011] Further, the inner side of the first sealing portion 41 extends radially inward to form the connecting portion 42, and there is a gap between the connecting portion 42 and the end surface of the inner ring of the first bearing 12.

[0012] Further, the second sealing portion 43 is cylindrical, and an annular groove for installing the elastic member 44 is provided on its outer wall.

[0013] Further, the sealing lip is one or more.

[0014] Further, the first shaft hole 10 includes a first hole body 101, a second hole body 102, a third hole body 103, and a fourth hole body 104 that are arranged in sequence and have diameters that decrease in sequence. The first bearing 12 and the first sealing portion 41 are arranged in the first hole body 101. The connecting portion 42 is located in the second hole body 102 or between the first hole body 101 and the second hole body 102. The second sealing portion 43 is located in the third hole body 103 or between the third hole body and the first hole body.

[0015] Further, there is a gap between the outer side end surface of the connecting portion 42 and the end surface of the second hole body 102.

[0016] Further, an installation cavity is formed in the motor housing 1. An end cover 2 is provided at the open end of the installation cavity. A cylindrical base 21 is provided on the end cover 2. A second shaft hole through which the tail of the main shaft 3 passes is provided on the base 21. A second oil seal 5 is provided between the inner wall of the second shaft hole 210 and the outer wall of the main shaft 3.

[0017] Further, the second oil seal 5 has a third sealing surface that fits against the inner wall of the second shaft hole 210, a fourth sealing surface that fits against the outer wall of the main shaft 3, and a limiting surface that contacts the stepped surface in the second shaft hole 210.

[0018] Beneficial effects

[0019] The sealing structure of the in-wheel motor of the present utility model can improve the sealing performance of the motor by adding an oil seal, prevent water or other impurities from entering the interior, and extend the service life. The oil seal structure is optimized to reduce the installation space, thereby reducing the axial installation dimension of the motor, making the motor structure more compact, reducing the axial width, and realizing the miniaturization of the motor. The multi-sealing surface structure is adopted, with good sealing performance and high reliability, thus extending the service life of the motor. The sealing structure of the in-wheel motor of the present utility model is compact, has a small axial installation space, good sealing performance, high reliability, and a long service life. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1 is a schematic structural diagram of the sealing structure of the in-wheel motor of the present utility model;

[0021] Figure 2 is Figure 1 an enlarged view of part A in

[0022] Figure 3 is a schematic structural diagram of the first shaft hole of the sealing structure of the in-wheel motor of the present utility model;

[0023] Figure 4 is Figure 1 an enlarged view of part B in DETAILED DESCRIPTION OF THE EMBODIMENTS

[0024] The embodiments of the present utility model will be described in detail below with reference to the drawings.

[0025] Refer to Figures 1-4, the present utility model provides a hub motor sealing structure for electric assist of vehicles, such as bicycles, tricycles, etc. It includes a motor housing 1 and a main shaft 3. The main shaft 3 is rotatably installed in the motor housing 1. The head and tail of the main shaft 3 extend outside the motor housing 1 and form a first shaft extension end and a second shaft extension end. The first shaft extension end and the second shaft extension end are used to be fixed to the vehicle frame as fixed ends. The motor housing 1 is used to be connected to the wheel hub as a rotating end, that is, a power output end. A first shaft hole 10 is opened in the motor housing 1. The first shaft hole 10 can accommodate the head of the main shaft 3 to pass through. The first shaft hole 10 is a stepped hole. A first bearing 12 is provided in the first shaft hole 10. The head of the main shaft 3 extends outside the motor housing 1 after passing through the first bearing, realizing a rotating connection with the motor housing 1. A first oil seal 4 is provided between the first shaft hole 10 and the main shaft 3. The first oil seal 4 includes a first sealing portion 41. The first sealing portion 41 is arranged between the stepped surface of the first shaft hole 10 and the end surface of the outer ring of the first bearing 12. The cross-section of the first sealing portion 41 is rectangular. The two end surfaces of the first sealing portion 41 respectively form a first sealing surface and a second sealing surface. Among them, the first sealing surface can fit on the stepped surface of the first shaft hole 10 and realize the first layer of end face sealing. The second sealing surface can fit on the end face of the outer ring of the first bearing 12 and realize the second layer of end face sealing, having double-end face sealing, with good sealing effect and high reliability. The inner side (or inner wall) of the first sealing portion 41 extends inwards (towards the main shaft direction) to form a connecting portion 42. There is a gap between the connecting portion 42 and the end surface of the inner ring of the first bearing 12. A second sealing portion 43 is provided inside the connecting portion 42. The second sealing portion 43 is cylindrical. One or more sealing lips are provided on the inner wall of the second sealing portion 43. The end of the sealing lip contacts the outer wall of the main shaft 3, thereby realizing radial sealing. In this embodiment, there are at least two sealing lips, which are arranged in sequence along the axis direction of the second sealing portion 43, forming two or more radial sealing structures. An annular groove is provided on the outer wall of the second sealing portion 43. An elastic member 44 is provided in the annular groove. The elastic member makes the sealing lip have a tendency to move radially inwards, that is, makes the sealing lip have a tendency to fit on the main shaft, ensuring the sealing effect and reliability. In this application, the elastic member 44 is a spring ring, with good elasticity and long service life.

[0026] In this application, the first shaft hole 10 includes a first hole body 101, a second hole body 102, a third hole body 103, and a fourth hole body 104 which are arranged in sequence from inside to outside and have diameters decreasing in sequence. Among them, the first bearing 12 and the first sealing portion 41 are arranged in the first hole body 101. The connecting portion 42 is located in the second hole body 102 or between the first hole body 101 and the second hole body 102. The second sealing portion 43 is located in the third hole body 103 or between the third hole body and the first hole body.

[0027] In this embodiment, the first oil seal includes a first sealing portion 41, a connecting portion 42, and a second sealing portion 43 integrally formed. It is made of rubber, silica gel, or other elastic materials. The end faces of both ends of the first sealing portion are not flush with the end faces of both ends of the connecting portion. Specifically, the second sealing surface (inner end face) of the first sealing portion fits against the outer ring end face of the first bearing, while there is a gap between the inner end face of the connecting portion and the end face of the first bearing; the first sealing surface (outer end face) of the first sealing portion fits against the stepped surface of the first hole body, while the outer end face of the connecting portion is located inside the second hole body and has a gap with the stepped surface of the second hole body; the inner end face of the second sealing portion is flush with the inner end face of the connecting portion, its outer end face is located inside the third hole body and does not contact the stepped surface of the third hole body. Two sealing lips are provided on the inner wall of the second sealing portion, and the two sealing lips are respectively arranged at both end positions of the second sealing portion. Its cross-section is a triangular structure, and an elastic component is located between the two sealing lips to ensure the degree of fit between the sealing lips and the outer wall of the main shaft, improving the radial sealing effect.

[0028] An installation cavity is formed in the motor housing 1 for installing functional components such as a stator, a rotor, a speed reducer, etc. An end cover 2 is provided at the open end of the installation cavity. A cylindrical base 21 is provided on the end cover 2. A second shaft hole 210 is opened on the base 21. The second shaft hole is coaxial with the first shaft hole and is used for the tail of the main shaft 3 to pass through. A second oil seal 5 is provided between the inner wall of the second shaft hole 210 and the outer wall of the main shaft 3 to achieve radial sealing between the second shaft hole 210 and the tail of the main shaft. The second shaft hole is also a stepped hole. The cross-section of the oil seal is rectangular and it is installed in the large hole of the stepped hole. The second oil seal 5 has a third sealing surface, a fourth sealing surface, and a limiting surface. Among them, the outer wall of the second oil seal forms the third sealing surface, which fits against the inner wall of the second shaft hole 210 to achieve external radial sealing. The inner wall of the second oil seal forms the fourth sealing surface, which fits against the outer wall of the main shaft 3 to achieve internal radial sealing. The end of the second oil seal forms the limiting surface, which contacts the stepped surface of the second shaft hole to achieve axial limiting. It is convenient for quick installation. At the same time, it provides installation limiting for the second seal, improving the installation accuracy and service reliability.

[0029] The hub motor sealing structure of the present utility model can improve the motor sealing performance by adding oil seals, avoid water or other impurities from entering the interior, and extend the service life; optimize the design of the oil seal structure, reduce the installation space, and further reduce the axial installation size of the motor, making the motor structure more compact and reducing the axial width to achieve the miniaturization of the motor; adopt a multi-sealing surface structure, with good sealing performance and high reliability, thereby extending the service life of the motor; the hub motor sealing structure of the present utility model has a compact structure, a small axial installation space, good sealing performance, high reliability, and a long service life.

[0030] The above are only the preferred embodiments of the present utility model. It should be noted that for those of ordinary skill in the art, without departing from the technical principle of the present utility model, several improvements and refinements can be made, and these improvements and refinements should also be regarded as the protection scope of the present utility model.

Claims

1. A hub motor sealing structure, characterized in that: It includes a motor housing and a main shaft rotatably installed in the motor housing, the head and tail of the main shaft both extend to the outside of the motor housing, the motor housing is provided with a first shaft hole for accommodating the head of the main shaft to pass through, a first bearing is provided in the first shaft hole, a first oil seal is provided between the first shaft hole and the main shaft, the first oil seal includes a first sealing portion arranged between a step surface of the first shaft hole and an end surface of an outer ring of the first bearing, the inner side of the first sealing portion extends inwardly and forms a connecting portion, the inner side of the connecting portion is provided with a second sealing portion, and the inner wall of the second sealing portion is provided with a sealing lip that contacts the outer wall of the main shaft and realizes radial sealing.

2. The hub motor sealing structure according to claim 1, characterized in that: The second sealing portion is covered with an elastic component which causes the sealing lip to move radially inwards.

3. The hub motor sealing structure according to claim 2, characterized in that: The elastic component is a spring.

4. The hub motor sealing structure according to claim 1, characterized in that: The first sealing portion includes a first sealing surface that is in contact with the stepped surface of the first shaft hole and a second sealing surface that is in contact with the outer ring end surface of the first bearing.

5. The hub motor sealing structure according to claim 1, characterized in that: The inner side of the first sealing portion extends radially inwardly and forms the connecting portion, and a gap is provided between the connecting portion and an end surface of the inner ring of the first bearing.

6. The hub motor sealing structure according to claim 2, characterized in that: The second sealing portion is cylindrical, and an annular groove for mounting the elastic component is provided on the outer wall of the second sealing portion.

7. The hub motor sealing structure according to claim 1, characterized in that: The first axial hole includes a first hole body, a second hole body, a third hole body and a fourth hole body which are arranged in sequence and have decreasing diameters in sequence. The first bearing and the first sealing portion are arranged in the first hole body. The connecting portion is located in the second hole body or between the first hole body and the second hole body. The second sealing portion is located in the third hole body or between the third hole body and the first hole body.

8. The hub motor sealing structure according to claim 7, characterized in that: There is a gap between the outer end surface of the connecting portion and the end surface of the second hole body.

9. The hub motor sealing structure according to claim 1, characterized in that: An installation cavity is formed in the motor housing, an open end of the installation cavity is provided with an end cover, the end cover is provided with a cylindrical base, the base is provided with a second shaft hole for accommodating the tail of the main shaft to pass through, and a second oil seal is provided between the inner wall of the second shaft hole and the outer wall of the main shaft.

10. The hub motor sealing structure according to claim 9, characterized in that: The second oil seal has a third sealing surface abutting against the inner wall of the second shaft hole, a fourth sealing surface abutting against the outer wall of the main shaft, and a limiting surface contacting against the step surface in the second shaft hole.

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