Universal joint assembly and method of servicing

Abstract

The present application relates to the technical field of universal joint assembly, and relates to a universal joint assembly and a maintenance method. The universal joint assembly comprises: a shaft sleeve assembly sleeved with a cross shaft assembly; a sealing unit forming a containing cavity with the cross shaft assembly and the shaft sleeve assembly; the diameter of part of the cross shaft assembly decreases in the direction close to the shaft sleeve assembly; the sealing unit comprises a sealing main body part, a first sealing part, a second sealing part and a third sealing part; the first sealing part, the second sealing part and the third sealing part respectively extend along the inner peripheral wall of the sealing main body part and incline to the outer peripheral wall of the cross shaft assembly; the interference amount of the second sealing part with the cross shaft assembly is greater than that of the first sealing part and the third sealing part; a rolling assembly is located in the containing cavity; a transmission shaft fork body comprises a fork body part and two ear holes; the shaft sleeve assembly is installed in the ear holes; a first clasp ring is arranged in the ear holes; and the shaft sleeve assembly abuts against the first clasp ring in the axial direction. The problem of how to control the contact between the sealing unit and the cross shaft assembly and prolong the service life of the sealing unit under the condition of ensuring the sealing performance is solved.

Description

Technical Field

[0001] This invention relates to the field of universal joint assembly technology, and more specifically, to a universal joint assembly and its maintenance method. Background Technology

[0002] In the field of universal joint assemblies, the universal joint shaft typically plays a role in transmitting torque and angular changes. After a period of use, wear can weaken the sealing performance of the universal joint shaft. For example, water may enter the shaft head, causing the rollers to rust and wear, or lubricating oil may leak out, generating high temperatures that damage the seal and cause problems such as bearing and journal seizing. Therefore, the sealing performance of the universal joint shaft is a key factor in ensuring transmission efficiency and service life.

[0003] Traditional universal joint assemblies typically employ a simple sealing structure for the cross shaft. This sealing structure usually has a large contact area with the cylindrical surface of the cross shaft journal, and the sealing structure and the cross shaft generally share relatively uniform forces to ensure a tight seal. However, under high-speed operation or harsh conditions, these structures are prone to problems such as incomplete sealing and short seal life due to wear of the entire sealing surface. This can lead to lubricant leakage or the entry of external contaminants (such as dust and moisture) into the cross shaft, causing corrosion and accelerated wear of the universal joint components, and reducing transmission accuracy and reliability. Therefore, how to precisely control the contact between the sealing unit and the cross shaft to extend the life of the sealing unit while ensuring a tight seal has become an urgent problem to be solved. Summary of the Invention

[0004] To address the problem of how to precisely control the contact between the sealing unit and the cross shaft assembly, and to extend the life of the sealing unit while ensuring sealing performance, this invention provides a universal joint assembly and a maintenance method.

[0005] In a first aspect, the present invention provides a universal joint assembly, comprising:

[0006] cross shaft assembly;

[0007] A bushing assembly is fitted onto the outer peripheral wall of the cross shaft assembly;

[0008] A sealing unit, together with a cross shaft assembly and a bushing assembly, forms a receiving cavity; the diameter of a portion of the cross shaft assembly decreases towards the bushing assembly; the sealing unit is sleeved on a portion of the cross shaft assembly; the sealing unit includes an integrally formed sealing body, a first sealing part, a second sealing part, and a third sealing part; the outer peripheral wall of the sealing body abuts against the inner peripheral wall of the bushing assembly; the first sealing part, the second sealing part, and the third sealing part extend obliquely along the inner peripheral wall of the sealing body towards the outer peripheral wall of the cross shaft assembly to form an interference fit with the outer peripheral wall of the cross shaft assembly; wherein, the interference fit between the second sealing part and the cross shaft assembly is greater than the interference fit between the first sealing part and the third sealing part and the cross shaft assembly, respectively;

[0009] A rolling assembly is located within the receiving cavity and between the cross shaft assembly and the bushing assembly;

[0010] The drive shaft fork includes a fork body portion and two coaxial lugs disposed on the fork body portion; a bushing assembly is installed in the lugs.

[0011] The first retaining ring is located inside the ear hole; the bushing assembly abuts against the first retaining ring along the axial direction.

[0012] In some embodiments, the cross shaft assembly includes an integrally formed cross shaft unit and a journal unit; the journal unit includes an integrally formed first journal and a second journal; the diameter of the first journal decreases toward the second journal; wherein the small-diameter end of the first journal is connected to the second journal; the large-diameter end of the first journal is connected to the cross shaft unit; the first journal and the second journal have concentric shafts; a sealing unit is sleeved on the outer peripheral wall of the first journal; a rolling assembly is located within a receiving cavity and between the second journal and the bushing assembly.

[0013] In some embodiments, the first sealing portion, the second sealing portion, and the third sealing portion are sequentially interference-fitted with the first journal towards the rolling assembly; the first sealing portion and the second sealing portion are inclined from the sealing body portion toward the side away from the rolling assembly; and the third sealing portion is inclined from the sealing body portion toward the side closer to the rolling assembly.

[0014] In some embodiments, the interference fit between the third sealing portion and the first journal is less than the interference fit between the second sealing portion and the first journal but greater than the interference fit between the first sealing portion and the first journal.

[0015] In some embodiments, the thickness of the first sealing portion along the axial direction of the journal unit is greater than the thickness of the second sealing portion and the third sealing portion; the thickness of the second sealing portion along the axial direction of the journal unit is less than the thickness of the first sealing portion but greater than the thickness of the third sealing portion.

[0016] In some embodiments, the universal joint assembly includes a sealing assembly; the sealing assembly includes a sealing unit and a skeleton unit; the skeleton unit is located between the bushing assembly and the sealing body; the outer peripheral wall of the skeleton unit abuts against the inner peripheral wall of the bushing assembly; the inner peripheral wall of the skeleton unit abuts against the outer peripheral wall of the sealing body.

[0017] In some embodiments, the skeleton unit includes an integrally formed first skeleton portion and a second skeleton portion; the first skeleton portion is disposed between the sealing body portion and the bushing assembly along the axial direction of the cross shaft assembly; one end of the first skeleton portion is connected to the second skeleton portion; the second skeleton portion extends radially along the cross shaft assembly; the projection of the rolling assembly along the axial direction of the cross shaft assembly covers the second skeleton portion.

[0018] In some embodiments, the drive shaft fork body is provided with a mounting groove; the mounting groove is located inside the ear hole; the first retaining ring engages with the mounting groove.

[0019] In some embodiments, it also includes:

[0020] The dustproof component is fitted onto the first journal and abuts against the bushing assembly.

[0021] Secondly, the present invention provides a method for maintaining a universal joint assembly, the method being applied to any of the universal joint assemblies described in the first aspect, the method comprising:

[0022] Based on the universal joint assembly during use, the gap between the end face of the cross shaft assembly and the inner wall of the bushing assembly is obtained.

[0023] When the gap between the end face of the cross shaft assembly and the inner wall of the bushing assembly is greater than the preset gap, the first retaining ring is replaced with the second retaining ring; wherein the thickness of the second retaining ring is greater than the thickness of the first retaining ring.

[0024] To address the problem of how to precisely control the contact between the sealing unit and the cross shaft assembly, and extend the lifespan of the sealing unit while ensuring sealing performance, this invention offers the following advantages:

[0025] This invention designs the sealing unit as an integrally formed sealing body, a first sealing part, a second sealing part, and a third sealing part, and differentiates the interference fits between the first, second, and third sealing parts and the cross shaft assembly, thus pre-setting precise and differentiated contact states and constructing a synergistic sealing system. The second sealing part, as the main seal, uses the maximum interference fit to ensure the core sealing pressure; the first and third sealing parts, as secondary seals, have smaller interference fits than the second sealing part, forming a gradient sealing barrier. This design results in a more scientific and rational distribution of contact force. The main sealing part bears the main sealing pressure, while the secondary sealing parts play a supporting sealing and dust removal role, effectively avoiding abnormal wear caused by excessive local interference fits. While ensuring excellent sealing performance, it significantly reduces the overall frictional resistance and frictional temperature rise of the sealing unit, thereby greatly extending its service life. Attached Figure Description

[0026] Figure 1 A cross-sectional view of a universal joint assembly according to one embodiment is shown;

[0027] Figure 2 An embodiment is shown. Figure 1 A partial schematic diagram of area A;

[0028] Figure 3 A schematic diagram of the structure of a universal joint assembly according to one embodiment is shown;

[0029] Figure 4 A flowchart illustrating a maintenance method for a universal joint assembly according to another embodiment is shown.

[0030] Figure label:

[0031] 10. Cross shaft assembly; 11. Cross shaft unit; 12. Journal unit; 121. First journal; 122. Second journal; 20. Bushing assembly; 30. Rolling assembly; 40. Sealing assembly; 41. Sealing unit; 411. Sealing body; 412. First sealing part; 413. Second sealing part; 414. Third sealing part; 42. Skeleton unit; 421. First skeleton part; 422. Second skeleton part; 50. Dustproof assembly; 61. First retaining ring; 70. Drive shaft fork body; 71. Fork body part; 72. Ear hole; 73. Mounting groove. Detailed Implementation

[0032] The invention will now be discussed with reference to several exemplary embodiments. It should be understood that these embodiments are described merely to enable those skilled in the art to better understand and thus implement the invention, and are not intended to imply any limitation on the scope of the invention.

[0033] As used herein, the term "comprising" and its variations are to be interpreted as open-ended terms meaning "including but not limited to". The term "based on" is to be interpreted as "at least partially based on". The terms "one embodiment" and "an embodiment" are to be interpreted as "at least one embodiment". The term "another embodiment" is to be interpreted as "at least one other embodiment". The terms "upper", "lower", "left", "right", "front", "rear", "top", "bottom", "inner", "outer", "vertical", "horizontal", "lateral", "longitudinal", etc., indicate orientations or positional relationships based on the orientations or positional relationships shown in the accompanying drawings. These terms are primarily for the purpose of better describing the invention and its embodiments and are not intended to limit the indicated devices, elements, or components to having a specific orientation or to be constructed and operated in a specific orientation. Furthermore, some of the above terms may be used to indicate other meanings besides orientations or positional relationships; for example, the term "upper" may in some cases indicate a dependency or connection relationship. Those skilled in the art can understand the specific meaning of these terms in this invention according to the specific circumstances. In addition, the terms "installed", "set", "equipped with", "connected", and "linked" should be interpreted broadly. For example, it can be a fixed connection, a detachable connection, or an integral structure; it can be a mechanical connection or an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium, or an internal connection between two devices, elements, or components. Those skilled in the art can understand the specific meaning of the above terms in this invention according to the specific circumstances. Furthermore, the terms "first," "second," etc., are mainly used to distinguish different devices, elements, or components (the specific types and structures may be the same or different), and are not used to indicate or imply the relative importance or quantity of the indicated devices, elements, or components. Unless otherwise stated, "a plurality of" means two or more.

[0034] The sealing structure of the universal joint assembly's cross shaft typically relies on a large-area contact between the sealing component and the cylindrical surface of the journal to achieve a sealing effect through an initial interference fit. However, this design has inherent limitations: during dynamic operation, the large-area tight contact leads to frictional heat accumulation and uniform surface wear, causing the sealing contact stress to decay rapidly, resulting in lubricant leakage and premature failure due to external contaminant intrusion. More importantly, once such overall wear occurs, the sealing structure often cannot be locally repaired or compensated, requiring complete replacement. This not only directly increases maintenance costs and downtime but also significantly shortens the reliable service life of the universal joint assembly due to its insufficient durability. Therefore, how to precisely control the contact between the sealing unit and the cross shaft to extend the life of the sealing unit while ensuring sealing performance has become an urgent problem to be solved.

[0035] Example 1

[0036] Please refer to Figure 1 This embodiment provides a universal joint assembly, including: a cross shaft assembly 10, a bushing assembly 20, a rolling assembly 30, a drive shaft fork 70, and a first retaining ring 61. The bushing assembly 20 is sleeved on the outer peripheral wall of the cross shaft assembly 10, so that after external parts engage with the bushing assembly 20, the bushing assembly 20 can rotate on the cross shaft assembly 10. The sealing unit 41, together with the cross shaft assembly 10 and the bushing assembly 20, forms a sealed receiving cavity to initially seal the rolling assembly 30; the rolling assembly 30 is located within the sealed receiving cavity and between the cross shaft assembly 10 and the bushing assembly 20. The receiving cavity is filled with lubricating oil or grease to fully lubricate the rolling assembly 30, reduce the friction between the rolling assembly 30 and the cross shaft assembly 10 and the bushing assembly 20, and allow the rolling assembly 30 to roll smoothly within the receiving cavity.

[0037] Furthermore, the diameter of part of the cross shaft assembly 10 decreases towards the bushing assembly 20; the sealing unit 41 is fitted onto part of the cross shaft assembly 10.

[0038] Please refer to Figure 1 and Figure 2 In this embodiment, the cross shaft assembly 10 includes an integrally formed cross shaft unit 11 and a journal unit 12; the journal unit 12 includes an integrally formed first journal 121 and a second journal 122; the diameter of the first journal 121 decreases towards the second journal 122, i.e., the first journal 121 is a tapered shaft. The small-diameter end of the first journal 121 is connected to the second journal 122; the large-diameter end of the first journal 121 is connected to the cross shaft unit 11; it is understood that one end of the second journal 122 is connected to the small-diameter end of the first journal 121, and the other end abuts against the bushing assembly 20. A sealing unit 41 is sleeved on the outer peripheral wall of the first journal 121 to form a sealed receiving cavity. When assembling the sealing unit 41, the tapered surface of the first journal 121 allows the sealing unit 41 to be installed from the small diameter end to the large diameter end along the inclined surface, which plays a guiding and positioning role, reducing the installation difficulty of the sealing unit 41. At the same time, it avoids the problem of the sealing unit 41 being rolled up, cut, or damaged due to right-angle steps or alignment difficulties in related technologies during the initial assembly stage, thus ensuring the integrity of the seal from the source.

[0039] Furthermore, the first journal 121 and the second journal 122 are concentric; the diameter of the second journal 122 is the same as the diameter of the small-diameter end of the first journal 121, so that the outer peripheral wall connecting the first journal 121 and the second journal 122 achieves a smooth transition, reducing the difficulty of production and the assembly difficulty of the various components of the cross shaft with the journal unit 12. The rolling assembly 30 is located in the receiving cavity and between the second journal 122 and the bushing assembly 20, so that the rolling assembly 30 rolls between the second journal 122 and the bushing assembly 20.

[0040] Please refer to Figure 2 Furthermore, the sealing unit 41 includes an integrally formed sealing body 411, a first sealing part 412, a second sealing part 413, and a third sealing part 414; the outer peripheral wall of the sealing body 411 abuts against the inner peripheral wall of the bushing assembly 20; the first sealing part 412, the second sealing part 413, and the third sealing part 414 extend obliquely along the inner peripheral wall of the sealing body 411 toward the outer peripheral wall of the cross shaft assembly 10 to form an interference fit with the outer peripheral wall of the cross shaft assembly 10. This structural design distributes the sealing function to the first sealing part 412, the second sealing part 413, and the third sealing part 414, avoiding a single sealing unit 41 bearing all the pressure and frictional heat. The interference fit between the second sealing part 413 and the cross shaft assembly 10 is greater than the interference fits between the first sealing part 412 and the third sealing part 414 and the cross shaft assembly 10, respectively.

[0041] In this embodiment, the interference fit between the third sealing part 414 and the first journal 121 is less than the interference fit between the second sealing part 413 and the first journal 121 but greater than the interference fit between the first sealing part 412 and the first journal 121.

[0042] Understandably, by setting a gradient distribution with the second sealing part 413 having the largest interference fit, the third sealing part 414 having the second largest, and the first sealing part 412 having the smallest, a reasonable distribution of sealing pressure is achieved, reducing the working load of any of the first sealing part 412, the second sealing part 413, and the third sealing part 414, so that frictional heat can be dispersed and more easily dissipated through the bushing assembly 20 and the journal unit 12, thereby slowing down the aging and hardening of the sealing material caused by high temperature and extending its service life.

[0043] Specifically, based on the interference fit design of the first sealing part 412, the second sealing part 413, and the third sealing part 414, the first sealing part 412 and the third sealing part 414 are secondary seals. The first sealing part 412 is used to prevent external impurities from entering the receiving cavity; the third sealing part 414 is used to prevent lubricating oil or grease from leaking out of the receiving cavity; the second sealing part 413 is the main seal, using the maximum interference fit. The second sealing part 413 also serves as the second line of defense for the first sealing part 412 and the third sealing part 414, preventing external impurities from entering the receiving cavity while also preventing lubricating oil or grease from leaking out of the receiving cavity. That is, the first sealing part 412, the second sealing part 413, and the third sealing part 414 form a gradient sealing barrier, which optimizes the sealing performance.

[0044] In this embodiment, the first sealing part 412, the second sealing part 413 and the third sealing part 414 are sequentially interference-fitted with the first journal 121 in the direction of approaching the rolling assembly 30; the first sealing part 412 and the second sealing part 413 are inclined from the sealing body part 411 to the side away from the rolling assembly 30; the third sealing part 414 is inclined from the sealing body part 411 to the side of approaching the rolling assembly 30.

[0045] Specifically, the first sealing part 412, with its structure inclined away from the sealing body 411 towards the side away from the rolling assembly 30, combined with the rotational movement of the sealing unit 41, can effectively throw intruding particles outwards instead of guiding them into the receiving cavity, effectively ensuring a seal while also serving as a dust scraper. The second sealing part 413 has a maximum interference fit, and its inclination direction is the same as that of the first sealing part 412, so that when the shaft rotates, the second sealing part 413 can throw intruding particles outwards and effectively prevent the leakage of lubricating oil or grease. The third sealing part 414 is inclined towards the receiving cavity and the rolling assembly 30, that is, it is inwardly positioned. For example, it serves as the last line of defense against dust and the first line of defense against the leakage of lubricating oil or grease. Its inward inclination makes its inner surface an inclined arc surface, that is, the lubricating oil or grease can collide with the arc surface during movement and then bounce back into the receiving cavity, further preventing the leakage of lubricating oil or grease. Therefore, the first sealing part 412, the second sealing part 413 and the third sealing part 414 form a sealing structure with synergistic effect, which optimizes the sealing performance.

[0046] In this embodiment, the thickness of the first sealing part 412 along the axial direction of the journal unit 12 is greater than the thickness of the second sealing part 413 and the third sealing part 414; the thickness of the second sealing part 413 along the axial direction of the journal unit 12 is less than the thickness of the first sealing part 412 and greater than the thickness of the third sealing part 414.

[0047] Understandably, by differentiating the thicknesses of the first sealing part 412, the second sealing part 413, and the third sealing part 414, the first sealing part 412, which bears the main assembly stress and external impact, is the thickest; the second sealing part 413, which needs to balance support and adaptability, is the next thickest; and the third sealing part 414 is the thinnest. This structural design ensures that each sealing part has mechanical properties that match its function, guaranteeing both the overall stability of the sealing unit 41 and the effective operation of each sealing part.

[0048] Understandably, during long-term operation, the sealing unit 41 in related technologies will inevitably wear down. In the cylindrical surface fit of related technologies, wear directly leads to a reduction in interference fit and a decrease in contact stress, resulting in a rapid decline in sealing performance and necessitating replacement of the sealing unit 41. However, in the conical fit of this embodiment, the first sealing part 412, the second sealing part 413, and the third sealing part 414 have different interference fits, functions, and thicknesses. The three sealing parts work together to optimize sealing performance. That is, slight wear allows the sealing unit 41 to slightly shift towards the larger diameter end under its own elasticity, thereby automatically compensating for the interference fit lost due to wear, achieving partial self-recovery of contact stress, greatly improving the stability of the seal throughout its lifespan, delaying seal failure, and resolving the contradiction between sealing performance, wear, and lifespan in related technologies.

[0049] In this embodiment, the universal joint assembly includes a sealing component 40; the sealing component 40 includes a sealing unit 41 and a skeleton unit 42; the skeleton unit 42 is located between the bushing assembly 20 and the sealing body 411, providing support for the sealing unit 41, stabilizing the sealing body 411, and further enhancing the sealing effect; the outer peripheral wall of the skeleton unit 42 abuts against the inner peripheral wall of the bushing assembly 20; the inner peripheral wall of the skeleton unit 42 abuts against the outer peripheral wall of the sealing body 411.

[0050] Please refer to Figure 1 and Figure 2 In this embodiment, the skeleton unit 42 includes an integrally formed first skeleton part 421 and a second skeleton part 422; the first skeleton part 421 is disposed between the sealing body part 411 and the bushing assembly 20 along the axial direction of the cross shaft assembly 10; one end of the first skeleton part 421 is connected to the second skeleton part 422; the second skeleton part 422 extends radially along the cross shaft assembly 10; the projection of the rolling assembly 30 along the axial direction of the cross shaft assembly 10 covers the second skeleton part 422.

[0051] Understandably, by having the projection of the rolling assembly 30 cover the second skeleton portion 422, the skeleton unit 42 is axially supported and positioned by the rolling assembly 30. This structure enhances the axial stiffness and stability of the entire universal joint assembly, prevents damage to the sealing interface due to component movement during transmission, and further improves the reliability of the seal.

[0052] Please refer to Figure 1 and Figure 3 In this embodiment, the drive shaft fork body 70 includes a fork body portion 71 and two coaxial ear holes 72 disposed in the fork body portion 71; the bushing assembly 20 is installed in the ear holes 72; the first retaining ring 61 is disposed in the ear holes 72; the bushing assembly 20 abuts against the first retaining ring 61 along the axial direction.

[0053] In this embodiment, the drive shaft fork body 70 is provided with a mounting groove 73; the mounting groove 73 is located inside the ear hole 72; the first retaining ring 61 is engaged with the mounting groove 73.

[0054] Specifically, the universal joint assembly includes a retaining ring assembly, which includes a first retaining ring 61 and a second retaining ring, wherein the thickness of the second retaining ring is greater than the thickness of the first retaining ring 61.

[0055] Understandably, by engaging the first retaining ring 61 within the mounting groove 73 of the fork body 71, a reliable and removable axial positioning structure is provided for the bushing assembly 20. In later use, the end face of the journal unit 12 is prone to wear. This design facilitates adjustment of the axial clearance during maintenance by replacing retaining rings of different thicknesses, providing convenience for long-term maintenance and extended lifespan of the universal joint assembly, while ensuring the stability of force transmission in the universal joint assembly.

[0056] In this embodiment, it also includes:

[0057] The dustproof component 50 is sleeved on the first journal 121 and abuts against the bushing assembly 20.

[0058] Understandably, the dustproof component 50, together with the bushing assembly 20 and the first journal 121, forms another sealed chamber. The dustproof component 50 is used to prevent large pollutants such as dust and mud from entering the sealed chamber, reducing the burden on the sealing unit 41, effectively avoiding abrasive wear, and providing pre-protection for the core sealing system, thereby indirectly extending the service life of the sealing unit 41.

[0059] Example 2

[0060] This embodiment provides a maintenance method for a universal joint assembly. By monitoring the change in clearance between the end face of the cross shaft assembly 10 and the inner wall of the bushing assembly 20, and replacing retaining rings of different thicknesses, precise compensation and restoration of the axial clearance of the universal joint assembly can be achieved. This maintenance method for the universal joint assembly is applied to a universal joint assembly according to Embodiment 1. Please refer to [reference needed]. Figure 4 The maintenance method for the universal joint assembly includes steps S10-S20:

[0061] S10, based on the universal joint assembly during use, obtain the gap between the end face of the cross shaft assembly 10 and the inner wall of the bushing assembly 20.

[0062] S20, when the gap between the end face of the cross shaft assembly 10 and the inner wall of the bushing assembly 20 is greater than the preset gap, the first retaining ring 61 is replaced with the second retaining ring; wherein the thickness of the second retaining ring is greater than the thickness of the first retaining ring 61.

[0063] It is understandable that the end face of the universal joint assembly 10 is the end face of the second journal 122 away from the first journal 121. With the movement of the universal joint assembly, the end face of the second journal 122 away from the first journal 121 or the sealing unit 41 is prone to wear. Wear in either case may affect the stability of force transmission or the sealing effect of the universal joint assembly. In this embodiment, by using a clearance greater than a preset clearance as the maintenance trigger condition, compared to the method in related technologies where wear of the cylindrical universal joint requires replacement of the sealing structure, this embodiment effectively reduces maintenance difficulty and cost, and avoids derivative failures such as lubricant leakage or contaminant intrusion caused by seal failure. The specific value of the preset clearance is subject to actual application and is not limited in this invention.

[0064] Furthermore, by replacing the second retaining ring, this method achieves precise compensation for the increased axial clearance caused by wear. After compensation, the initial axial preload of each component inside the universal joint assembly is restored, reconstructing the stable working environment required for the sealing unit 41, enabling it to continue to perform effective sealing. Moreover, this maintenance method benefits from the conical surface of the first journal 121 and the structure and different interference fits of the sealing unit 41. It eliminates the need to replace the core transmission components or the sealing unit 41 itself; the performance of the universal joint assembly can be restored simply by replacing the second retaining ring, significantly reducing maintenance costs.

[0065] Those skilled in the art will understand that the above embodiments are specific examples of implementing the present invention, and in practical applications, various changes can be made in form and detail without departing from the scope of the present invention.

Claims

1. A universal joint assembly, characterized in that, include: cross shaft assembly; A bushing assembly is fitted onto the outer peripheral wall of the cross shaft assembly; A sealing unit, together with the cross shaft assembly and the bushing assembly, forms a receiving cavity; the diameter of a portion of the cross shaft assembly decreases towards the bushing assembly; the sealing unit is sleeved on a portion of the cross shaft assembly; the sealing unit includes an integrally formed sealing body, a first sealing part, a second sealing part, and a third sealing part; the outer peripheral wall of the sealing body abuts against the inner peripheral wall of the bushing assembly; the first sealing part, the second sealing part, and the third sealing part extend obliquely along the inner peripheral wall of the sealing body towards the outer peripheral wall of the cross shaft assembly to form an interference fit with the outer peripheral wall of the cross shaft assembly; wherein, the interference fit between the second sealing part and the cross shaft assembly is greater than the interference fit between the first sealing part and the third sealing part and the cross shaft assembly, respectively; A rolling assembly is located within the receiving cavity and between the cross shaft assembly and the bushing assembly; A drive shaft fork body includes a fork body portion and two coaxial lugs disposed on the fork body portion; the bushing assembly is installed in the lugs. A first retaining ring is disposed within the ear hole; the bushing assembly abuts against the first retaining ring axially; wherein, the cross shaft assembly includes a journal unit; the journal unit includes an integrally formed first journal and a second journal; the first sealing portion, the second sealing portion, and the third sealing portion are sequentially interference-fitted with the first journal in the direction closer to the rolling assembly; the first sealing portion and the second sealing portion are inclined from the sealing body portion toward the side away from the rolling assembly; the third sealing portion is inclined from the sealing body portion toward the side closer to the rolling assembly; the interference fit between the third sealing portion and the first journal is less than the interference fit between the second sealing portion and the first journal but greater than the interference fit between the first sealing portion and the first journal.

2. The universal joint assembly according to claim 1, characterized in that, The cross shaft assembly includes an integrally formed cross shaft unit and the journal unit; the diameter of the first journal decreases towards the second journal; wherein the small-diameter end of the first journal is connected to the second journal; the large-diameter end of the first journal is connected to the cross shaft unit; the first journal and the second journal have concentric shafts; the sealing unit is sleeved on the outer peripheral wall of the first journal; the rolling assembly is located within the receiving cavity and between the second journal and the bushing assembly.

3. A universal joint assembly according to claim 1, characterized in that, The thickness of the first sealing portion along the axial direction of the journal unit is greater than the thickness of the second sealing portion and the third sealing portion; the thickness of the second sealing portion along the axial direction of the journal unit is less than the thickness of the first sealing portion but greater than the thickness of the third sealing portion.

4. A universal joint assembly according to claim 1, characterized in that, The universal joint assembly includes a sealing component; the sealing component includes a sealing unit and a skeleton unit; the skeleton unit is located between the bushing assembly and the sealing body; the outer peripheral wall of the skeleton unit abuts against the inner peripheral wall of the bushing assembly; the inner peripheral wall of the skeleton unit abuts against the outer peripheral wall of the sealing body.

5. A universal joint assembly according to claim 4, characterized in that, The skeleton unit includes an integrally formed first skeleton part and a second skeleton part; the first skeleton part is disposed between the sealing body part and the bushing assembly along the axial direction of the cross shaft assembly; one end of the first skeleton part is connected to the second skeleton part; the second skeleton part extends radially along the cross shaft assembly; the projection of the rolling assembly along the axial direction of the cross shaft assembly covers the second skeleton part.

6. A universal joint assembly according to claim 1, characterized in that, The drive shaft fork body is provided with a mounting groove; the mounting groove is located inside the ear hole; the first retaining ring is engaged with the mounting groove.

7. A universal joint assembly according to claim 2, characterized in that, Also includes: A dustproof component is fitted onto the first journal and abuts against the bushing assembly.

8. A method for maintaining a universal joint assembly, characterized in that, The maintenance method for the universal joint assembly is applied to a universal joint assembly as described in any one of claims 1-7, and the maintenance method for the universal joint assembly includes: Based on the universal joint assembly during use, the gap between the end face of the cross shaft assembly and the inner wall of the bushing assembly is obtained. When the gap between the end face of the cross shaft assembly and the inner wall of the bushing assembly is greater than a preset gap, the first retaining ring is replaced with a second retaining ring; wherein the thickness of the second retaining ring is greater than the thickness of the first retaining ring.

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