A wheel hub unit provided with a reinforcing layer

Abstract

This utility model provides a hub unit with a reinforced surface layer, including a spindle. A connecting flange is integrally formed on the outer side of the spindle, and a cavity is vertically formed in the center of the spindle. An inner lower raceway is formed on the outer surface of the spindle above the connecting flange, and a shoulder is provided on the spindle above the inner lower raceway. Compared with the prior art, this utility model has the following advantages: It adopts a dual-ball bearing load-sharing structure, with the large-diameter second ball bearing priority to bear radial loads, while the small-diameter first ball bearing focuses on axial loads. Compared with the traditional single ball bearing assembly, this improves the overall load-bearing capacity. The carbonitriding hardening layer on the ball surface increases the surface hardness of the balls. Combined with a nanocrystalline titanium nitride coating, it significantly reduces the coefficient of friction and extends the fatigue life of the balls. The outer ring, inner ring, and spindle surface are reinforced with a copper-tin-zinc ternary alloy layer, with a local thickening of 0.1-0.3 mm in the raceway area, resulting in a more uniform distribution of contact stress and effectively suppressing fatigue crack formation.

Description

Technical Field

[0001] This utility model is a wheel hub unit with a reinforcing layer on its surface, belonging to the field of wheel hub units. Background Technology

[0002] In the modern automotive industry, the wheel hub unit is a key component connecting the wheel and the axle. Its performance directly affects the safety, reliability and durability of the vehicle. With the popularization of new energy vehicles and the development of intelligent driving technology, the automotive industry has put forward more stringent requirements for wheel hub units: they need to increase the load-bearing capacity by more than 20% while reducing the weight by 10%-15%, and at the same time ensure that the fatigue life of the components exceeds 1 million cycles.

[0003] Traditional wheel hub unit surface treatment processes are relatively simple. If only ordinary quenching or simple coating is used, it is difficult to meet the requirements of high strength, high wear resistance and long service life. As a key area that bears high contact stress, the raceway cannot be specifically strengthened by traditional treatment methods, which easily leads to fatigue cracks and pitting corrosion, which seriously restricts the overall performance of the wheel hub unit. As the automotive industry continues to increase its requirements for lightweight, high reliability and long service life, the design and manufacturing technology of traditional wheel hub units can no longer meet market demands. Therefore, it is necessary to design a wheel hub unit with a surface reinforcement layer. Utility Model Content

[0004] In view of the shortcomings of the existing technology, the purpose of this utility model is to provide a hub unit with a reinforcing layer on the surface to solve the problems mentioned in the background art.

[0005] To achieve the above objectives, this utility model is implemented through the following technical solution: a hub unit with a reinforcing layer on its surface includes a spindle, an integrally formed connecting flange on the outer side, a vertically formed cavity in the center, an inner lower raceway on the outer surface of the spindle above the connecting flange, and a shoulder on the spindle above the inner lower raceway.

[0006] The second ball bearing assembly is arranged around the inner lower raceway;

[0007] The first ball bearing assembly has a smaller diameter than the second ball bearing assembly and is located above the shoulder.

[0008] The outer ring is fitted outside the first ball group and the second ball group, and its inner surface is provided with an outer upper raceway and an outer lower raceway that are adapted to the first ball group and the second ball group.

[0009] The inner ring is located between the first ball set and the spindle, and its outer surface has an inner upper raceway that is adapted to the first ball set.

[0010] A dust cover is installed on top of the spindle and inner ring.

[0011] Furthermore, the bottom of the outer ring extends downward to form a connecting portion, and a sealing assembly is provided inside the connecting portion. The sealing assembly includes a fixing frame that is interference-fitted with the inner wall of the connecting portion, and a sealing element installed inside the fixing frame. The bottom of the sealing element is provided with at least two sealing lips arranged radially, and each sealing lip forms a sealing contact with the outer surface of the spindle.

[0012] Furthermore, the bottom of the dust cover is integrally provided with a threaded connection part, and the top of the inner surface of the outer ring is provided with an internal thread that is compatible with the threaded connection part.

[0013] Furthermore, the inner ring is interference-fitted onto the outer wall of the mandrel, and the bottom of the inner ring abuts against the upper surface of the shoulder.

[0014] Furthermore, the first ball assembly consists of a first cage and a plurality of first balls arranged in a circular array on the first cage, with the two sides of the first balls respectively making rolling contact with the outer upper raceway and the inner upper raceway.

[0015] Furthermore, the second ball assembly consists of a second cage and a plurality of second balls arranged in a circular array on the second cage, with the two sides of the second balls making rolling contact with the outer lower raceway and the inner lower raceway, respectively. The outer diameter of the first cage is smaller than the diameter of the second cage, and the diameter of the first ball is smaller than the diameter of the second ball.

[0016] Furthermore, the outer ring, inner ring, and mandrel are all provided with a copper, tin, and zinc ternary alloy reinforcing layer, and the thickness of the reinforcing layer at the outer upper raceway, outer lower raceway, inner upper raceway, and inner lower raceway is 0.1-0.3 mm thicker than that at the non-raceway locations.

[0017] Furthermore, both the outer surfaces of the first ball and the second ball are provided with a carbonitriding hardening layer, and the outer side of the carbonitriding hardening layer is provided with a nanocrystalline titanium nitride coating.

[0018] The beneficial effects of this utility model are:

[0019] 1. The dual ball bearing load distribution structure is adopted. The large-diameter second ball bearing set prioritizes radial load, while the small-diameter first ball bearing set focuses on axial load. Compared with the traditional single ball bearing set, the overall load-bearing capacity can be improved. The carbonitriding hardening layer on the ball surface can improve the surface hardness of the ball. Combined with the nanocrystalline titanium nitride coating, the friction coefficient can be significantly reduced and the fatigue life of the ball can be extended. The outer ring, inner ring and mandrel surfaces are reinforced with a copper, tin and zinc ternary alloy layer. The raceway is locally thickened by 0.1-0.3mm, which makes the contact stress distribution more uniform and effectively inhibits the generation of fatigue cracks.

[0020] 2. The dust cover is fixed to the inner thread of the outer ring through the threaded connection part, covering the top of the spindle and the inner ring to prevent dust, mud and other impurities from entering the internal raceway. The connecting part at the bottom of the outer ring is equipped with a fixing bracket and a seal. The sealing lip at the bottom of the seal contacts the outer surface of the spindle to form multiple radial seals, preventing grease leakage and external contaminants from entering, and ensuring the lubrication environment of the ball assembly. Attached Figure Description

[0021] Other features, objects, and advantages of this invention will become more apparent from the following detailed description of non-limiting embodiments with reference to the accompanying drawings:

[0022] Figure 1 This is a schematic diagram of the combined structure of a hub unit with a reinforcing layer on its surface according to the present invention;

[0023] Figure 2 This is a schematic diagram of the combined cross-sectional structure of a hub unit with a reinforcing layer on its surface according to the present invention;

[0024] Figure 3 This is a schematic diagram showing the disassembled structure of a hub unit with a reinforcing layer on its surface according to the present invention;

[0025] Figure 4 This is a schematic diagram of the split cross-section structure of a hub unit with a reinforcing layer on its surface according to the present invention;

[0026] Figure 5 This is a schematic diagram of the first ball bearing structure of a hub unit with a reinforcing layer on its surface according to the present invention.

[0027] In the diagram: 1. Connecting flange; 101. Groove; 2. Outer ring; 201. Connecting part; 202. Lower outer raceway; 203. Upper outer raceway; 204. Internal thread; 3. Dust cover; 301. Threaded connection part; 4. Inner ring; 401. Upper inner raceway; 5. Sealing assembly; 501. Fixing bracket; 502. Seal; 6. First ball assembly; 601. First retainer; 602. First ball; 7. Second ball assembly; 701. Second retainer; 702. Second ball; 8. Mandrel; 801. Cavity; 802. Lower inner raceway; 803. Shoulder; 804. Riveting part; 9. Fixing flange; 10. Carbonitriding hardened layer; 11. Nanocrystalline titanium nitride coating. Detailed Implementation

[0028] To make the technical means, creative features, objectives and effects of this utility model easier to understand, the present utility model will be further described below in conjunction with specific embodiments.

[0029] Please see Figures 1 to 5This utility model provides a technical solution: a hub unit with a reinforced surface, including a spindle 8, a connecting flange 1 integrally formed on the outer side of the spindle 8, and a cavity 801 vertically formed in the center of the spindle 8, an inner lower raceway 802 formed on the outer surface of the spindle 8 above the connecting flange 1, and a shoulder 803 formed on the spindle 8 above the inner lower raceway 802, a second ball set 7 surrounding the inner lower raceway 802, a first ball set 6 with a smaller diameter than the second ball set 7 and located above the shoulder 803, an outer ring 2 sleeved on the outer side of the first ball set 6 and the second ball set 7, and an outer upper raceway 20 formed on its inner surface that is adapted to the first ball set 6 and the second ball set 7. 3 and the outer lower raceway 202, the inner ring 4 is located between the first ball set 6 and the spindle 8, and its outer surface is provided with an inner upper raceway 401 adapted to the first ball set 6. The dust cover 3 is placed on the top of the spindle 8 and the inner ring 4. The coordinated design of the spindle 8, the first ball set 6, the second ball set 7 and the outer ring 2 and the inner ring 4 realizes the precise distribution of load. The inner lower raceway 802 on the spindle 8 cooperates with the second ball set 7 to mainly bear the radial load (such as the weight of the vehicle body) during the vehicle's operation. The first ball set 6, located above the shoulder 803, focuses on dealing with axial loads, such as the lateral force during steering, due to the difference in diameter between the first ball set 6 and the second ball set 7 and its special layout.

[0030] Please see Figure 4 The bottom of the outer ring 2 extends downward to form a connecting part 201, and a sealing component 5 is provided inside the connecting part 201. The sealing component 5 includes a fixing frame 501 that is interference-fitted with the inner wall of the connecting part 201, and a sealing element 502 installed inside the fixing frame 501. The bottom of the sealing element 502 is provided with at least two sealing lips arranged radially. Each sealing lip forms a sealing contact with the outer surface of the spindle 8. The multi-ring sealing lip design can effectively resist the intrusion of external pollutants such as mud, water, and sand, and has a higher waterproof and dustproof level. Compared with the traditional single-layer sealing structure, the protective performance is improved.

[0031] Please see Figure 2 and Figure 4 The bottom of the dust cover 3 is integrally provided with a threaded connection part 301, and the top of the inner surface of the outer ring 2 is provided with an internal thread 204 that matches the threaded connection part 301. The threaded connection method is simple to operate and can quickly complete the installation and removal of the dust cover 3 without special tools, which greatly shortens the maintenance time.

[0032] Please see Figure 4 The inner ring 4 is interference-fitted onto the outer wall of the mandrel 8, and the bottom of the inner ring 4 abuts against the upper surface of the shoulder 803. The inner ring 4 is tightly fitted onto the outer wall of the mandrel 8 through interference fit. By utilizing the friction force generated by the elastic deformation of the material, a gapless and high-strength connection is formed, which effectively prevents the inner ring 4 from axially moving or circumferentially sliding on the mandrel 8. Combined with the abutting design between the bottom of the inner ring 4 and the upper surface of the shoulder 803, the axial displacement of the inner ring 4 is further restricted.

[0033] Please see Figure 4 The first ball assembly 6 consists of a first cage 601 and a plurality of first balls 602 arranged in a ring array on the first cage 601. The two sides of the first balls 602 are in rolling contact with the outer upper raceway 203 and the inner upper raceway 401, respectively. The first ball assembly 6 consists of a first cage 601 and a ring array of first balls 602. This design ensures that the multiple first balls 602 are in uniform contact with the outer upper raceway 203 and the inner upper raceway 401, which can evenly distribute the axial load and avoid local stress concentration. The first cage 601 isolates the first balls 602 to prevent direct collision and wear between the first balls 602.

[0034] Please see Figure 4 The second ball set 7 consists of a second cage 701 and several second balls 702 arranged in a ring array on the second cage 701. The two sides of the second balls 702 are in rolling contact with the outer lower raceway 202 and the inner lower raceway 802, respectively. The outer diameter of the first cage 601 is smaller than the diameter of the second cage 701, and the diameter of the first ball 602 is smaller than the diameter of the second ball 702. The diameter of the second cage 701 is larger than the diameter of the first cage 601, and the diameter of the second ball 702 is larger than the diameter of the first ball 602. This differentiated design achieves a precise division of labor between the two ball sets. The second ball set 7 focuses on radial loads, while the first ball set 6 focuses on axial loads. The two work together to make the load distribution of the hub unit more reasonable under complex working conditions. Compared with the single ball set design, the overall load-bearing efficiency is improved.

[0035] Please see Figure 4 The outer ring 2, inner ring 4, and mandrel 8 are all reinforced with a copper-tin-zinc ternary alloy layer. The thickness of the reinforced layer at the outer upper raceway 203, outer lower raceway 202, inner upper raceway 401, and inner lower raceway 802 is 0.1-0.3 mm thicker than the non-raceway areas. Through synergistic effects of the elements, the copper-tin-zinc ternary alloy reinforced layer on the surfaces of the outer ring 2, inner ring 4, and mandrel 8 forms a dense and uniform protective structure. Copper provides good thermal conductivity, reducing frictional heat accumulation during operation; tin enhances… The lubrication performance reduces direct wear between components; zinc enhances corrosion resistance. The outer upper raceway 203, outer lower raceway 202, inner upper raceway 401, and inner lower raceway 802 are high-stress areas that directly contact the ball bearing assembly. The thickness of the reinforcement layer is locally increased by 0.1-0.3mm to specifically enhance the load-bearing capacity. At the same time, the precise local reinforcement avoids material redundancy in non-critical parts. While ensuring strength, compared with the full surface uniform thickness reinforcement design, the overall weight of the wheel hub unit can be reduced.

[0036] Please see Figure 5The outer surfaces of the first ball 602 and the second ball 702 are both provided with a carbonitriding hardening layer 10, and a nanocrystalline titanium nitride coating 11 is provided on the outer side of the carbonitriding hardening layer 10. The carbonitriding hardening layer 10 increases the surface hardness by infiltrating carbon and nitrogen elements into the ball matrix. The nanocrystalline titanium nitride coating 11 has an extremely low coefficient of friction, which greatly reduces the frictional resistance and heat generation between the ball and the raceway, thereby reducing energy loss during operation.

[0037] Detailed implementation: In use, the spindle 8 is rigidly connected to the wheel via the connecting flange 1, transmitting power to the wheel hub unit. The inner lower raceway 802 of the spindle 8 cooperates with the second ball set 7, utilizing the larger diameter second ball 702 to primarily bear the radial load during vehicle movement; the first ball set 6 above the shoulder 803, with its smaller diameter first ball 602, focuses on handling axial loads. The dual ball sets achieve precise load distribution. The outer ring 2 rolls with the first and second ball sets via the outer upper raceway 203 and outer lower raceway 202, distributing and transmitting the load; the inner upper raceway 4 of the inner ring 4... 01 works in conjunction with the first ball set 6 to ensure rotational accuracy. The threaded connection 301 of the dust cover 3 engages with the internal thread 204 of the outer ring 2. Combined with the multi-ring sealing lip of the sealing component 5 inside the bottom connection 201 of the outer ring 2, it forms double protection, isolating external contaminants and preventing grease leakage. The copper, tin, and zinc ternary alloy reinforcement layer on the surface of each component, especially the local thickening design of the raceway, enhances wear resistance and load-bearing capacity. The carbonitriding hardening layer 10 and the nanocrystalline titanium nitride coating 11 on the surface of the first ball 602 and the second ball 702 reduce the coefficient of friction and increase hardness, thus reducing wear.

[0038] Although this specification describes embodiments, not every embodiment contains only one independent technical solution. This narrative style is merely for clarity. Those skilled in the art should consider the specification as a whole. The technical solutions in each embodiment can also be appropriately combined to form other embodiments that can be understood by those skilled in the art.

Claims

1. A wheel hub unit with a reinforcing layer on its surface, characterized in that, include: The mandrel has an integral connecting flange on the outside and a vertical cavity in the center. An inner lower raceway is formed on the outer surface of the mandrel above the connecting flange, and a shoulder is provided on the mandrel above the inner lower raceway. The second ball bearing assembly is arranged around the inner lower raceway; The first ball bearing assembly has a smaller diameter than the second ball bearing assembly and is located above the shoulder. The outer ring is fitted outside the first ball group and the second ball group, and its inner surface is provided with an outer upper raceway and an outer lower raceway that are adapted to the first ball group and the second ball group. The inner ring is located between the first ball set and the spindle, and its outer surface has an inner upper raceway that is adapted to the first ball set. A dust cover is installed on top of the spindle and inner ring.

2. A wheel hub unit with a surface reinforcement layer according to claim 1, characterized in that: The bottom of the outer ring extends downward to form a connecting part, and a sealing assembly is provided inside the connecting part. The sealing assembly includes a fixing frame that is interference-fitted with the inner wall of the connecting part, and a sealing element installed inside the fixing frame. The bottom of the sealing element is provided with at least two sealing lips arranged radially, and each sealing lip forms a sealing contact with the outer surface of the spindle.

3. A wheel hub unit with a surface reinforcement layer according to claim 1, characterized in that: The bottom of the dust cover is integrally provided with a threaded connection part, and the top of the inner surface of the outer ring is provided with an internal thread that matches the threaded connection part.

4. A wheel hub unit with a surface reinforcement layer according to claim 1, characterized in that: The inner ring is interference-fitted onto the outer wall of the mandrel, and the bottom of the inner ring abuts against the upper surface of the shoulder.

5. A wheel hub unit with a surface reinforcement layer according to claim 1, characterized in that: The first ball assembly consists of a first cage and a plurality of first balls arranged in a circular array on the first cage, with the two sides of the first balls respectively making rolling contact with the outer upper raceway and the inner upper raceway.

6. A wheel hub unit with a surface reinforcement layer according to claim 5, characterized in that: The second ball assembly consists of a second cage and a plurality of second balls arranged in a circular array on the second cage. The two sides of the second balls are in rolling contact with the outer lower raceway and the inner lower raceway, respectively. The outer diameter of the first cage is smaller than the diameter of the second cage, and the diameter of the first ball is smaller than the diameter of the second ball.

7. A wheel hub unit with a surface reinforcement layer according to claim 1, characterized in that: The outer ring, inner ring, and mandrel are all provided with a copper, tin, and zinc ternary alloy reinforcement layer, and the thickness of the reinforcement layer at the outer upper raceway, outer lower raceway, inner upper raceway, and inner lower raceway is 0.1-0.3 mm thicker than that at the non-raceway parts.

8. A wheel hub unit with a surface reinforcement layer according to claim 6, characterized in that: Both the first and second balls have a carbonitriding hardening layer on their outer surfaces, and a nanocrystalline titanium nitride coating is provided on the outer side of the carbonitriding hardening layer.

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