Oil seal with double-sealing structure and hub motor thereof

Abstract

The utility model relates to an oil seal with a double sealing structure and a hub motor thereof, an oil seal body comprises a metal framework and an elastic body, the metal framework is embedded in the elastic body, the elastic body is provided with a first sealing lip part, a second sealing lip part and a shaft hole matching part, the first sealing lip part and the second sealing lip part are both of a circumferential structure and are located at different radial heights, the radial height of the shaft hole matching part is smaller than that of the first sealing lip part and that of the second sealing lip part, and a grease storage groove is formed between the first sealing lip part and the second sealing lip part. The oil seal has the beneficial effects that the labyrinth type double sealing effect of the oil seal is good, the oil seal is provided with an independent oil storage space, the oil lubrication is sufficient, the loss current is small, the wear-resistant service life is long, the air tightness of the hub motor is good, the efficiency of the motor is high, the foreign matter prevention function of the outer framework structure is strong, and the service life of the built-in lip oil seal is long.

Description

Technical Field

[0001] The utility model relates to the technical field of wheel hub motors, and specifically discloses an oil seal with a double sealing structure and a wheel hub motor thereof. Background Art

[0002] As a convenient and economical means of transportation, electric vehicles are widely used in people's daily transportation. The application conditions of electric vehicles are complex and harsh, such as immersion in water, soaking in water, muddy water, sunshine, high temperature and high humidity, low temperature, etc. During the use of electric vehicles, the water ingress and burning of the motor has always been the top fault problem in the after-sales service of electric vehicles. Many manufacturers have begun to improve the waterproof effect of the motor by improving the oil seal structure of the hub motor, or adding external protective structural parts to the oil seal, such as adding dust covers, increasing the sealing length of the oil seal, etc. Even if various measures have achieved the purpose of improving the waterproof effect to a certain extent, they still cannot fully take into account the comprehensive factors such as simplifying the assembly structure of the motor, improving the working environment of the oil seal, improving the lubrication effect of the oil seal, and extending the service life of the oil seal. Therefore, the sealing performance and use effect of the existing hub motor oil seal are not satisfactory, the service life is not optimistic, and the damage rate is high.

[0003] For example, application publication number CN117267379A discloses an oil seal structure with good sealing performance, including an oil seal body, a first oil seal lip is installed inside the oil seal body, a second oil seal lip is arranged below the first oil seal lip, a third oil seal lip is arranged below the second oil seal lip, a rotating groove is provided inside the oil seal body, a slip ring is installed inside the rotating groove, an inner ring is fixedly connected to the side of the slip ring close to the center of the oil seal body, an extension plate is fixedly arranged on the surface of the inner ring, an inner groove is provided on the upper surface of the oil seal body, a groove is provided on the lower surface of the oil seal body, a first telescopic spring is installed in the inner groove, and a second telescopic spring is installed in the groove. Although the first, second, and third oil seal lips are mentioned in the article, the oil seal is still a conventional inner hole sealing oil seal structure, that is, the outer ring is statically fixedly connected, the inner hole is dynamically rotated, and all lips are arranged at the same radial height. The final beneficial effect is that the elastic force of the spring inside the oil seal can be adjusted, and impurities outside the lip can be easily cleaned. The oil seal disclosed in the document still has a single seal at a single radial height, the lip is exposed and easily damaged, it is easily aged by light, the grease cannot be replenished, resulting in dry grinding and causing the oil seal lip to wear and fail, and other problems still have not been effectively solved.

[0004] For another example, application publication number CN117628186A discloses a bidirectionally sealed rotary oil seal, comprising: an external ring shell, and an outer sealing ring and an inner sealing ring for bidirectional sealing, the external ring shell is annular, and an outer retaining ring is provided at one end of the external ring shell, the outer wall of the outer retaining ring is connected to the inner wall of the external ring shell, the inner wall of the outer retaining ring is connected to the outer sealing ring, the outer retaining ring and the outer sealing ring are located on the same side, and the inner sealing ring is connected to the outer retaining ring. The outer sealing ring greatly reduces the contact area between the outer sealing ring and the motor shaft to reduce the friction between the outer sealing ring and the motor shaft. The inner sealing ring can play a leak-proof role in the motor, the outer sealing ring can prevent impurities outside the motor from entering the motor, and the space left between the inner sealing ring and the outer sealing ring can store and prevent leakage when the lubricating medium leaks outward. The oil seal of this structure consists of a multi-part sealing lip, but it is still sealed at the same radial height. The oil storage structure is a cavity separately set in the oil seal body to prevent leakage. The sealing effect of the oil seal cannot be improved. The lip is also directly facing the external environment. Although it is protected by the outer shell, the exposed lip part cannot be effectively protected.

[0005] For example, the dual-material sealing structure oil seal disclosed in the authorization announcement number CN221033957U has a core technology of dual materials, that is, the sealing lip at the same radial height is composed of two different materials to form the seal. The oil storage function and the lip protection function are not designed, and the problems of oil seal aging, lack of oil, easy dry grinding, short life and poor single-layer sealing protection cannot be solved.

[0006] In the industry, technicians have continuously optimized the sealing length of the oil seal and added multiple means to ensure lubrication. However, from a structural analysis, it is not suitable for the application scenarios of hub motors: because the inside of the hub motor is the permanent magnet and armature, the outside is the natural environment, and the installation space of the oil seal is limited. The existing oil seal structure is basically suitable for inner rotor motors, that is, the application scenario with grease lubrication on one side. Therefore, for hub motor manufacturers, how to improve the sealing performance and service life of hub motors is a goal that the industry has been pursuing and improving. Utility Model Content

[0007] In view of the deficiencies in the prior art, the utility model discloses an oil seal with a double sealing structure and good sealing effect and sufficient lubrication, and a hub motor thereof.

[0008] In order to achieve the above object, the utility model discloses an oil seal with a double sealing structure, and its technical solution is as follows:

[0009] An oil seal with a double sealing structure, the oil seal body includes a metal frame and an elastomer, the metal frame is embedded in the elastomer, the elastomer is provided with a first sealing lip, a second sealing lip and a shaft hole matching portion, the first sealing lip and the second sealing lip are both circumferential structures and are respectively at different radial heights, the radial height of the shaft hole matching portion is smaller than the radial height of the first sealing lip and the second sealing lip, and a grease storage groove is provided between the first sealing lip and the second sealing lip. This design scheme aims to set multiple sealing lips of the oil seal at different radial heights, and at the same time, use the connecting part between the two lips to form a groove-shaped structure with lubricating grease storage, which can provide sufficient space for storing grease, provide lubricating grease continuously for the rotary seal of the motor, reduce the risks of dry grinding and burning of the oil seal lip caused by grease reduction, and at the same time, the lubrication is sufficient and the oil seal resistance loss is small.

[0010] As a further optimization of the above technical solution: the oil seal body is located outside the rotating structure, the first sealing lip and the second sealing lip cooperate with the rotating structure to form a rotating sealing structure, and the rotating structure and the grease storage tank form a closed cavity. This solution uses the assembly structural characteristics of the oil seal to construct a dynamic sealing cavity. The two sealing lips and the rotating structure extending into the grease storage tank of the oil seal form a labyrinth-like rotating sealing structure. The sealing path has multiple bends, and the sealing effect is better. At the same time, the groove cavity is just suitable for storing spare lubricating grease, killing two birds with one stone.

[0011] As a further optimization of the above technical solution: a reserve lubricating grease is provided in the closed cavity. In this design solution, the reserve grease can timely replenish the motor rotation loss or long-term volatilization loss, ensure that the two sealing lips of the oil seal and the matching part of the rotating structure are fully lubricated, reduce the occurrence of dry wear and damage of the oil seal and burning of the sealing lips, and at the same time, effective lubrication can effectively reduce the rotation resistance of the motor, reduce the wear of the oil seal, extend the life of the oil seal sealing lips, and improve the efficiency of the motor.

[0012] As a further optimization of the above technical solution: a shaft is inserted into the shaft hole matching part, and the shaft hole matching part is fixed with the shaft by interference fit. This assembly structure has a fixed inner hole and an outer rotating seal, which better meets the sealing requirements of the hub motor.

[0013] As a further optimization of the above technical solution: the radial height difference between the first sealing lip and the second sealing lip ranges from 3 mm to 50 mm. This solution is suitable for various power requirements of the hub motor.

[0014] As a further optimization of the above technical solution: the axial thickness of the oil seal body in the installation direction is 5mm to 50mm. This solution can effectively ensure the length of the double waterproof path of the motor without affecting the motor efficiency.

[0015] The utility model also discloses a hub motor, including the oil seal with double sealing structure in the above technical solution, and also including a support cover, the support cover is the rotating structure, the supporting cover and the first sealing lip and the second sealing lip are matched with two circumferential surfaces at different radial heights, and the front section of the matching part of the rotating structure is provided with a guide slope. In the motor of this design, the structure of the double sealing lips at different radial heights and the grease storage groove constitute a labyrinth seal and lubrication system, which not only ensures excellent sealing and waterproofing functions, but also provides long-term continuous lubrication and oil supply characteristics, and the assembly guide structure effectively prevents the occurrence of scratches, lip eversion and other phenomena during the assembly process of the oil seal.

[0016] Compared with the prior art, the advantages and positive effects of the utility model are:

[0017] The oil seal of the utility model is reasonably designed with multiple sealing lips at different radial heights according to the structural characteristics of the operation of the outer rotor motor, so as to construct a multiple, maze-like, tortuous sealing path. At the same time, the oil storage tank structure for preparing grease is also reasonably designed, which can store enough spare grease to supply the grease consumed by the motor due to long-term operation. The oil seal has small resistance, sufficient lubrication and long service life.

[0018] The electric vehicle hub motor provided by the utility model is used to drive the electric vehicle. Compared with the existing electric vehicle motors, it has excellent airtight and waterproof functions. Its sufficient lubricating grease reserve greatly reduces the rotational resistance between the oil seal and the rotating part of the motor, and the lubrication is sufficient, and the oil seal lip wear is small, which is particularly suitable for the use scenarios of high-speed motors (≥30km / h speed); the labyrinth-type sealing path of the oil seal of the utility model significantly improves the waterproof effect of the motor; the oil seal of the utility model is provided with double sealing lips at different radial heights, and the waterproof effect is doubled without increasing the axial size of the motor assembly. When the electric vehicle hub motor provided by the utility model is assembled, the opening direction of the oil seal sealing lip faces the motor rotating structure, and there is a small gap between the oil seal sealing lip and the rotating structure. In conventional oil seal installation, the opening direction of the sealing lip directly faces the external environment. Different from the installation form of conventional oil seals, the opening direction of the oil seal lip of the utility model faces away from the external environment. This implicit distribution form effectively avoids the problem of aging of the oil seal sealing lip due to long-term exposure to sunlight, and greatly prolongs its service life. In the back-facing installation structure of the utility model, the metal skeleton of the oil seal faces outward, and the soft sealing lip is well hidden, which greatly reduces the probability of damage to the oil seal lip due to impact of large foreign objects in the external environment, and effectively prolongs the service life of the oil seal. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1 It is a schematic diagram of the cross-sectional structure of the oil seal body in the utility model.

[0020] Figure 2 It is a schematic diagram of the assembly structure of the oil seal body in the utility model.

[0021] Figure 3 for Figure 2 Schematic diagram of the enlarged structure at point A in the middle.

[0022] Figure 4 This is a schematic diagram of the assembly structure of the hub motor in the utility model

[0023] In the figure, 1, oil seal body; 2, shaft; 3, rotating structure; 4, bearing; 5, rotor; 6, stator; 11, metal frame; 12, elastomer; 51, rim; 52, magnetic ring; 53, permanent magnet; 61, stator core; 62, bracket; 63, bushing; 64, enameled wire; 121, first sealing lip; 122, second sealing lip; 123, shaft hole matching part; 124, grease storage tank. DETAILED DESCRIPTION

[0024] The following are specific embodiments of the present invention and the technical solution of the present invention are further described in detail in conjunction with the accompanying drawings. It should be noted that the described embodiments are only intended to facilitate the understanding of the present invention by those skilled in the art and do not have any limiting effect on the protection scope of the present invention.

[0025] Embodiment 1:

[0026] See also Figure 1 , 2 As shown in Figures 3 and 4, the present embodiment provides an oil seal with a double sealing structure, wherein the oil seal body 1 includes a metal frame 11 and an elastomer 12, wherein the metal frame 11 is embedded in the elastomer 12 to play a supporting role. The oil seal body 1 is a rotating body structure, wherein the first sealing lip 121, the second sealing lip 122 and the shaft hole matching portion 123 are designed on the elastomer 12, wherein the first sealing lip 121 and the second sealing lip 122 are both circumferential structures. The first sealing lip 121 and the second sealing lip 122 are relatively distributed, i.e., the first sealing lip 121 and the second sealing lip 122 are at different radial heights respectively. The radial height of the shaft hole matching portion 123 is smaller than the radial height of the first sealing lip 121 and the second sealing lip 122, and a grease storage groove 124 is provided between the first sealing lip 121 and the second sealing lip 122.

[0027] The oil seal body 1 is located on the outside of the rotating structure 3, and the shaft 2 is inserted into the shaft hole matching part 123, and the shaft hole matching part 123 and the shaft 2 form an elastic interference fixed connection. A gap is left between the end face of the oil seal body 1 and the side of the rotating structure 3, and the matching part of the rotating structure 3 and the oil seal body 1 extends into the grease storage groove 124 of the oil seal body 1. The first sealing lip 121 and the second sealing lip 122 are respectively in contact and sealed with the inner and outer circumferential surfaces of the matching part of the rotating structure 3, and the first sealing lip 121 and the second sealing lip 122 of the rotating structure 3 and the oil seal body 1 constitute an elastic interference rotating sealing structure. A guide slope is provided at the front section of the matching part of the rotating structure 3. The first sealing lip 121 and the second sealing lip 122 are made of nitrile rubber and are elastic. Grease lubrication is provided in the grooves of the first sealing lip 121 and the second sealing lip 122. The bottom of the grease storage groove 124 still has a certain closed cavity after being matched with the rotating structure 3, and the excess reserve lubricating grease is stored in the closed cavity. In this embodiment, the axial thickness of the oil seal body 1 in the installation direction is 5mm to 50mm, and further, the axial thickness of the oil seal body 1 is 10mm to 11mm; the radial height difference between the first sealing lip 121 and the second sealing lip 122 ranges from 3mm to 50mm, the inner diameter of the first sealing lip 121 is 46mm to 48mm, and the inner diameter of the second sealing lip 122 is 56mm to 58mm. The elastic body 12 of the oil seal body 1 is made of nitrile rubber and lubricated with grease.

[0028] like Figure 4 As shown, a hub motor includes a rotor 5, a stator 6, a support cover, a shaft 2, and also includes the oil seal body 1 in the above technical solution. The rotating structure 3 in the above technical solution is the support cover of the hub motor. The support cover is used to refer to the rotating structure 3 for description. The supporting cover cooperates with the first sealing lip 121 and the second sealing lip 122 at two circumferential surfaces at different radial heights. The rotor 5 is sleeved on the outside of the stator 6, and the rotor 5 is connected to the shaft 2 through the support cover and the bearing 4. The rotor 5 includes a rim 51, a magnetic ring 52 and a permanent magnet 53. The rim 51 and the magnetic ring 52 are welded and fixed, and the permanent magnet 53 is arranged on the inner circumference of the magnetic ring 52. The stator 6 includes a stator core 61, an enameled wire 64 and a bracket 62. The stator core 61 is made of stacked silicon steel sheets. A sleeve 63 is welded at the center of the bracket 62. The sleeve 63 and the shaft 2 are connected and fixed by interference. The outer circumference of the bracket 62 cooperates with the inner hole of the stator core 61. The support cover is located on the side of the stator 6 , the support cover is fixedly connected to the rotor 5 by screws, the outer ring of the bearing 4 is fixedly connected to the center of the support cover by interference fit, and the inner hole of the bearing 4 is matched with the shaft 2 .

[0029] The reserve lubricating grease is used to continuously replenish the grease lost by the motor, ensure sufficient lubrication effect, reduce the rotation resistance of the oil seal body 1, and delay the wear of the first sealing lip 121 and the second sealing lip 122 of the oil seal body 1. The closed cavity ensures that the reserved grease will not directly contact the outside world to prevent deterioration or infiltration of foreign matter, and the bottom of the grease storage groove 124 and the first sealing lip 121 and the second sealing lip 122 form a sealing structure similar to a maze, and the sealing effect is significant. The first sealing lip 121 and the second sealing lip 122 are arranged at different radial heights, which effectively reduces the axial structural size of the motor, which is precisely the important size limited by the compact installation space of the hub motor. The structure of the utility model opens the multiple sealing structures in the radial direction without increasing the axial opening size, which greatly enhances the problem of the waterproof ability of the motor. Compared with the oil seal of the traditional structure used in the existing motor, the oil seal of the utility model has an additional waterproof structure on the basis of not changing the motor assembly structure and assembly size, and has better airtight waterproof ability. In addition, the design of the grease storage groove 124 ensures long-term effective lubrication of the oil seal, thereby reducing the wear of the first sealing lip 121, the second sealing lip 122 and the matching part of the rotating structure 3, greatly extending the service life of the oil seal. In addition, different from the installation method of conventional motors, the axial openings of the first sealing lip 121 and the second sealing lip 122 of the oil seal body 1 face the rotating structure 3 and are away from the external environment. The contained first sealing lip 121 and the second sealing lip 122 effectively avoid the infiltration and collision of external foreign matter caused by direct exposure to the harsh external environment, reduce the probability of the sealing lip being damaged by foreign matter, and also avoid direct sunlight, delay the aging of the first sealing lip 121 and the second sealing lip 122, greatly improve the use environment of the oil seal, and increase its service life.

[0030] The embodiments described above are only preferred embodiments of the present invention, which are only used to illustrate the technical solution of the present invention, and are not intended to limit the patent scope of the present invention. Any modification or equivalent replacement of the technical solution of the present invention using the contents of the present invention specification and drawings, or any direct or indirect application in other related technical fields, are also included in the patent protection scope of the present invention.

[0031] Although the oil seal body 1, shaft 2, rotating structure 3, bearing 4, rotor 5, stator 6, metal frame 11, elastic body 12, rim 51, magnetic ring 52, permanent magnet 53, stator core 61, bracket 62, sleeve 63, enameled wire 64, first sealing lip 121, second sealing lip 122, shaft hole matching part 123, grease storage tank 124 and other terms are used more frequently in this article, the possibility of using other terms is not excluded. The use of these terms is only for more convenient description and explanation of the essence of the utility model; interpreting them as any additional restrictions is contrary to the spirit of the utility model.

Claims

1. An oil seal with a double sealing structure, wherein the oil seal body (1) comprises a metal frame (11) and an elastic body (12), characterized in that: The metal skeleton (11) is embedded in the elastomer (12); the elastomer (12) is provided with a first sealing lip (121), a second sealing lip (122) and an axial hole matching portion (123); the first sealing lip (121) and the second sealing lip (122) are both circular structures and are respectively located at different radial heights; the radial height of the axial hole matching portion (123) is smaller than the radial heights of the first sealing lip (121) and the second sealing lip (122); and a grease storage groove (124) is provided between the first sealing lip (121) and the second sealing lip (122).

2. The oil seal with a double sealing structure according to claim 1, characterized in that: The oil seal body (1) is located outside the rotating structure (3); the first sealing lip (121) and the second sealing lip (122) respectively cooperate with the rotating structure (3) to form a rotating sealing structure; the rotating structure (3) and the grease storage groove (124) form a closed cavity.

3. The oil seal with a double sealing structure according to claim 2, characterized in that: The closed cavity is provided with reserve lubricating grease.

4. The oil seal with a double sealing structure according to claim 1, characterized in that: A shaft (2) is inserted into the shaft hole matching portion (123), and the shaft hole matching portion (123) is fixed to the shaft (2) by interference fit.

5. The oil seal with a double sealing structure according to claim 1, characterized in that: The radial height difference between the first sealing lip (121) and the second sealing lip (122) ranges from 3 mm to 50 mm.

6. The oil seal with a double sealing structure according to claim 1, characterized in that: The axial thickness of the oil seal body (1) in the installation direction is 5 mm to 50 mm.

7. A hub motor, characterized in that: It comprises an oil seal with a double sealing structure as claimed in any one of claims 2 to 6, and also comprises a support cover, wherein the support cover is the rotating structure (3), and the matching parts of the support cover and the first sealing lip (121) and the second sealing lip (122) are two circumferential surfaces located at different radial heights, and the front section of the matching part of the rotating structure (3) is provided with a guide slope.

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