Seals and wheel hub drives

Abstract

The present invention relates to a sealing device (11) and a wheel hub drive device, wherein the sealing device (11) has an annular sealing body (3) made of elastic material, wherein the sealing body (3) has a sealing lip (7) pressed against a sealing surface, and the sealing lip (7) forms a dynamic seal with the sealing surface, wherein the sealing device (11) also has a reinforcement ring (6) integrally arranged with the sealing lip (7), wherein the stiffness of the reinforcement ring (6) is greater than the stiffness of the sealing lip (7), and the wheel hub drive device has the above-mentioned sealing device.

Description

Technical Field

[0001] The present invention relates to a sealing device, which is used for dynamically sealing a sealing surface. The present invention also relates to a wheel hub drive device for a vehicle, which has the above-mentioned sealing device. Background Art

[0002] The traditional sealing device mainly consists of a dust cover and a sealing body made of rubber. A skeleton is often provided in the sealing body, and the sealing body has a sealing lip that forms a dynamic seal with the sealing surface to seal the lubricating oil. In addition, the sealing body also has a dust lip that forms a dynamic seal with the dust cover to prevent contaminants from entering the oil area.

[0003] However, when the sealing device is used in a wheel hub drive device, for example, the flange shaft has a large radial runout relative to the sealing device because the sealing device is arranged between the housing and the flange shaft. In view of this situation, the waist connecting the main body of the sealing body and the sealing lip is usually designed to be slender, and the deformation of the sealing body caused by the radial runout can be absorbed by the slender waist to ensure the good shape of the sealing lip. However, the sealing lip, the dust lip, the dust cover and the sealing surface form an inner cavity. When the temperature of the lubricating oil rises, high pressure will be generated in the inner cavity, and the slender waist cannot withstand a large pressure. If you want to withstand high pressure, you need to widen or thicken the waist. In addition, in order to ensure that the sealing lip fits tightly with the sealing surface of the shaft, for example, a spring for applying pressure to the sealing lip is often provided on the sealing lip. The elastic force of the spring cannot be too large, otherwise the sealing lip will be excessively deformed, affecting the dynamic sealing effect. However, in the case of large shaft runout, the instantaneous impact of the shaft on the sealing lip is very large, which is likely to overcome the elastic force of the spring, causing the sealing lip to separate from the shaft, thereby failing to seal. Therefore, it is necessary to provide a suitable sealing device for harsh working conditions, especially for working conditions where the sealing surface has large vibration relative to the sealing device and the temperature is high. Summary of the invention

[0004] Therefore, the technical problem to be solved by the present invention is to overcome the above technical difficulties and provide a sealing device which can be applied to working conditions where the radial runout of the sealing surface relative to the sealing device is large and the temperature is high, especially for wheel hub drive devices.

[0005] The above technical problem is solved by a sealing device, which has an annular sealing body made of elastic material, wherein the sealing body has a sealing lip pressed against a sealing surface, and the sealing lip forms a dynamic seal with the sealing surface. According to the present invention, the sealing device also has a reinforcement ring integrated with the sealing lip, wherein the stiffness of the reinforcement ring is greater than the stiffness of the sealing lip.

[0006] In the present invention, the sealing surface can be a rotating surface to be sealed. The rotating surface is, for example, the outer peripheral surface of a rotating body. If the rotating body is a hollow rotating body, the sealing surface can also be the inner peripheral surface of the rotating body. The rotating body is, for example, a cylinder, a truncated cone or a hollow cylinder. The rotating body can be rotating or stationary, as long as the sealing surface or the rotating surface has circumferential movement relative to the sealing device. For example, in the application of a wheel hub drive device, what is to be sealed is the shaft section of the flange shaft, so the sealing surface is the outer surface of the shaft section. In the present invention, the elastic material constituting the sealing body is, for example, rubber.

[0007] According to the design of the present invention, by designing the waist to be wider or thicker, it is possible to ensure that the sealing lip and the sealing surface of, for example, a shaft, fit closely under high temperature and high pressure conditions. In particular, in the case where the radial runout of the sealing surface relative to the sealing device is large, by integrating a reinforcement ring with greater rigidity in and / or on the sealing lip (the reinforcement ring is made of, for example, metal or plastic), the radial movement of the sealing lip can be reduced when, for example, the sealing surface of the shaft has a large instantaneous impact on the sealing lip, thereby ensuring that the sealing lip is always pressed against the sealing surface to achieve a reliable sealing effect. At the same time, arranging the above-mentioned reinforcement ring in / on the sealing lip is equivalent to increasing the local rigidity of the sealing lip, thereby reducing the degree of deformation of the sealing lip, and thus can advantageously ensure the sealing effect of the sealing lip. It should be noted that the reinforcement ring is preferably not in direct contact with the sealing surface, that is, the reinforcement ring is not arranged at a position of the sealing lip that is in direct contact with the sealing surface, such as the cutting edge.

[0008] According to a preferred embodiment of the present invention, the reinforcement ring is integrated with the sealing lip by a vulcanization process. The sealing lip and the reinforcement ring can be reliably and tightly connected by the vulcanization process. In addition, even in the case of relatively flexible setting of the geometric shape of the reinforcement ring and / or the arrangement position in the sealing lip, the vulcanization process can meet the requirements of reliable connection without adding excessive costs.

[0009] According to another preferred embodiment of the present invention, the sealing device further comprises a frame for supporting the sealing body, wherein the frame is also fixed in the sealing body by vulcanization. Thus, the sealing device is strengthened so that the sealing device can better maintain its shape. It is further preferred that the reinforcing ring and the frame are fixed simultaneously in the same vulcanization process step. Thus, the sealing device according to the present invention can be formed in one step, reducing the manufacturing cost.

[0010] According to another preferred embodiment of the present invention, the ring cross section of the reinforcement ring is circular or quadrilateral. The ring cross section has such a profile that the reinforcement ring is generated by rotating the profile around an axis coplanar with the ring cross section. The ring cross section being circular or quadrilateral is conducive to convenient manufacturing and cost saving.

[0011] According to another preferred embodiment of the present invention, the reinforcement ring is arranged on the axial end of the sealing lip, so that the reinforcement ring can be conveniently positioned when the reinforcement ring is integrated with the sealing lip, especially in a vulcanization process.

[0012] According to another preferred embodiment of the present invention, a spring, i.e., a self-tightening coil spring, is provided on the sealing lip to apply a force to the sealing lip. The contraction force of the spring generates a certain radial compression force on the sealing surface of, for example, a shaft. After the sealing device has been running for a period of time, the pressure of the sealing lip on the sealing surface will decrease or even disappear. Therefore, the addition of the spring can compensate for the self-tightening force at any time to ensure the reliability of the sealing device. Preferably, a groove for accommodating the spring is provided on the side of the sealing lip away from the sealing surface. Thereby, the spring is reliably positioned.

[0013] According to another preferred embodiment of the present invention, the sealing device further comprises a dust cover, and the sealing body further comprises a dust lip, which extends axially toward the dust cover and forms a seal with a radial section of the dust cover. The dust cover and the dust lip are advantageously arranged on the side opposite to the oil area relative to the sealing lip mainly used to prevent oil leakage. Thus, the sealing device can be used in working conditions such as a wheel hub drive device with a large amount of external pollutants.

[0014] In addition, the above technical problem is also solved by a wheel hub drive for a vehicle, which has a sealing device according to the above. For example, the sealing device can be arranged between a flange shaft for driving a wheel hub and a housing for supporting the wheel hub drive. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] The preferred embodiments of the present invention are schematically described below in conjunction with the accompanying drawings.

[0016] Figure 1 is a half-section view of a wheel hub drive device according to the present invention,

[0017] Figure 2 is a schematic half-section view of a sealing device according to a first preferred embodiment, and

[0018] Figure 3 is a schematic half-sectional view of a sealing device according to a second preferred embodiment.

[0019] Identical parts or parts with the same function are provided with the same reference numerals. DETAILED DESCRIPTION

[0020] Figure 1A half-section view of a wheel hub drive device according to the present invention is shown. The wheel hub drive device comprises a wheel hub (not shown) for supporting a vehicle tire, a flange shaft 13, a hub bearing 18 for supporting the flange shaft 13, a reducer 15, a motor, a motor housing 12 for holding, and a sealing device 11. A motor having a rotor 16 is installed in the motor housing 12, and the rotor 16 drives the flange shaft 13 via the reducer 15. The hub bearing 18 is arranged between the flange shaft and the wheel hub drive device housing. The flange shaft 13 has a flange plate 14 at the end, and a plurality of screws 17 are arranged on the flange plate 14. These screws 17 are evenly distributed on the circumference of the flange plate 14, and the screws 17 are fixedly connected to the wheel hub, so that the flange shaft 13 is fixedly connected to the wheel hub. When the rotor 16 of the motor rotates the flange shaft 13 through the reducer 15 composed of planetary gears, the flange shaft 13 drives the wheel hub, thereby driving the wheel.

[0021] A sealing device 11 according to the present invention is further provided between the flange shaft 13 and the motor housing 12 in the radial direction and between the outer housing and the reducer 15 in the axial direction.

[0022] The figure shows the wheel hub drive device in the assembled state. During the assembly process, for the consideration of overall axisymmetry, the rotation axis of the wheel hub is aligned with the central axis of the motor housing 12, the rotation axis of the reducer 15, the rotation axis of the wheel hub bearing 18, the rotation axis of the sealing device 11 and the central axis of the flange shaft (in Figure 1 In the working state, since the flange shaft 13 is connected to the wheel, the wheel will cause the flange shaft 13 to deflect after being loaded with the weight of the whole vehicle. In the case of the deflected operation of the flange shaft 13, the sealing device 11 placed on the flange shaft will cause a large eccentricity. Therefore, it can be considered to set the central axis of the flange shaft 13 and the central axis of the motor housing 12 not to coincide with each other during assembly, so that the above two central axes can coincide with each other during operation without eccentricity. In this case, there will be higher requirements for the sealing device placed between the flange shaft 13 and the motor housing 12, which is required to maintain a good sealing effect under large radial vibration.

[0023] Figure 2 1 is a sealing device according to a first preferred embodiment of the present invention, wherein a cross-sectional view cut along the center line of the sealing device is schematically shown. In this embodiment, the sealing device is used as follows Figure 1 The wheel hub drive shown.

[0024] like Figure 2As shown, the sealing device has a sealing body 3, a skeleton 4 and a dust cover 1, wherein the sealing body 3 is made of rubber. The main body of the sealing body 3 and the dust cover 1 are both against the motor housing (not shown) in the wheel hub drive device. A metal skeleton 4 is provided in the sealing body 3 by a vulcanization process, and the sealing body 3 has a sealing lip 7 and a dust lip 2. The sealing lip 7 forms a dynamic seal with the flange shaft (not shown) in the wheel hub drive device to prevent lubricating oil from entering the motor area. The waist 5 connecting the sealing lip 7 and the skeleton 4 is thicker. The reinforcement ring 6 is a circular plate, and the stiffness of the reinforcement ring 6 is greater than the stiffness of the sealing body 3. The reinforcement ring 6 is installed on the axial end side of the sealing lip 7 away from the main body of the sealing body 3 by a vulcanization process, thereby reducing the radial movement of the sealing lip 7, and thereby increasing the local stiffness of the sealing lip 7, so that while the waist 5 absorbs the deformation caused by the eccentric arrangement of the flange shaft, the sealing lip 7 will not produce a large deformation, thereby not affecting the sealing effect. In addition, the dust lip 2 extends from the skeleton 4 axially toward the dust cover 1 and forms a seal with a radial section of the dust cover 1 to prevent contaminants from entering the oil region.

[0025] Figure 3 A schematic cross-sectional view of a sealing device according to a second preferred embodiment of the present invention is shown. In this embodiment, the sealing device is also used as Figure 1 The hub drive device shown in the figure. Different from the first embodiment, the sealing device is provided with a spring 8 for applying force to the sealing lip 7. As shown in the figure, an annular groove is provided on the side of the sealing lip 7 facing away from the flange shaft (not shown), that is, on the radial outer side of the sealing lip 7. The spring 8 is accommodated in the groove, and the sealing lip 7 is pressed against the flange shaft by the tension of the spring 8, thereby enhancing the sealing effect.

[0026] Although possible embodiments are described by way of example in the above description, it should be understood that there are still a large number of variations of embodiments through the combination of all known and other technical features and embodiments that are easily conceivable to the skilled person. It should also be understood that the exemplary embodiment is only an example and that such an embodiment in no way limits the scope of protection, application and configuration of the present invention. The above description is more to provide the skilled person with a technical guide for converting at least one exemplary embodiment, wherein various changes can be made, especially changes in the functions and structures of the components, as long as they do not depart from the scope of protection of the claims.

[0027] Reference numerals list

[0028] 1 Dust cover

[0029] 2 Dust lip

[0030] 3 Sealing body

[0031] 4 Skeleton

[0032] 5. Waist

[0033] 6 Reinforcement ring

[0034] 7 Sealing lip

[0035] 8 Spring

[0036] 11 Sealing device

[0037] 12 Motor housing

[0038] 13 Flange shaft

[0039] 14 Flange plate

[0040] 15 Reducer

[0041] 16 Motor rotor

[0042] 17 Screw

[0043] 18 Wheel bearing

Claims

1. A sealing device (11), comprising an annular sealing body (3) made of elastic material rubber, wherein: The sealing body (3) has a sealing lip (7) pressed against a sealing surface, and the sealing lip (7) forms a dynamic seal with the sealing surface, and is characterized in that the sealing device (11) also has a reinforcement ring (6) integrally arranged with the sealing lip (7), wherein the reinforcement ring (6) is made of metal or plastic, the rigidity of the reinforcement ring (6) is greater than the rigidity of the sealing lip (7), the reinforcement ring (6) is arranged on the axial end of the sealing lip (7), and the reinforcement ring (6) does not directly contact the sealing surface.

2. The sealing device (11) according to claim 1, characterized in that The reinforcement ring (6) and the sealing lip (7) are integrated through a vulcanization process.

3. The sealing device (11) according to claim 2, characterized in that The sealing device (11) comprises a frame (4) for supporting the sealing body (3), wherein the frame (4) is fixed in the sealing body (3) by vulcanization.

4. The sealing device (11) according to claim 3, characterized in that The reinforcement ring (6) and the frame (4) are fixed in the same vulcanization process step.

5. The sealing device (11) according to claim 1, characterized in that: The cross section of the reinforcing ring (6) is circular or quadrilateral.

6. The sealing device (11) according to claim 1, characterized in that A spring (8) is arranged on the sealing lip (7) and can apply a force to the sealing lip (7).

7. The sealing device (11) according to claim 6, characterized in that A groove for accommodating the spring (8) is provided on the side of the sealing lip (7) facing away from the sealing surface.

8. The sealing device (11) according to claim 1, characterized in that The sealing device (11) also has a dust cover (1), and the sealing body (3) also has a dust lip (2). The dust lip (2) extends axially toward the dust cover (1) and forms a seal with a radial section of the dust cover (1).

9. A wheel hub drive device for a vehicle, characterized in that: The wheel hub drive has a sealing device (11) according to any of the preceding claims.

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