Cross universal joint and universal coupling

Abstract

The invention discloses a cross universal joint and a universal coupling, and relates to the technical field of couplings. The universal joint comprises a fork head assembly, a cross shaft assembly and a bearing sleeve assembly. The cross shaft assembly comprises a cross shaft and a bearing inner ring arranged on a shaft head in an interference sleeving mode. The bearing sleeve assembly is arranged on the bearing inner ring in a sleeved mode and installed in the fork head bearing hole. Oil grooves are formed in the surfaces of the fork head bearing hole and the cross shaft head, and oil is injected through the oil injection hole to form an oil film so as to assist in lossless disassembly of the bearing sleeve assembly and the bearing inner ring. A rolling type plane bearing is integrated in the bearing sleeve assembly, and a double-sealing structure is adopted to be matched with the cylindrical surface of a bearing inner ring for sealing. According to the universal joint, the manufacturing difficulty of the universal joint is reduced, the problems of serious axial abrasion and sealing failure of a traditional structure are solved, disassembly, assembly and maintenance are convenient, and the service life is remarkably prolonged.

Description

Technical Field

[0001] This invention relates to the field of coupling technology, and in particular to a universal joint and universal coupling. Background Technology

[0002] With the development of mechanical transmission technology, the universal joint, a commonly used coupling technology, has emerged. This technology boasts significant advantages such as high load-bearing capacity, long service life, high transmission efficiency, and smooth transmission, and is widely used in various heavy machinery transmission applications in metallurgy, hoisting, engineering transportation, mining, petroleum, and shipbuilding. Among these applications, the universal joint, as the core component for achieving variable-angle power transmission, connects two shafts that are not on the same axis or have a large angle between their axes, enabling them to rotate continuously at a constant angular velocity. It is the most critical and commonly worn part in the entire transmission system.

[0003] In traditional technology, existing universal joint bearings generally employ a close-packed roller structure without an inner ring. In this structure, the rollers directly contact the surface of the universal joint head for rolling; axial positioning is typically achieved through copper alloy washers, relying on sliding friction to bear axial forces. For sealing, a double-lip seal is generally used, with the seal positioned on the arcuate surface of the universal joint head. Furthermore, the fork head and bearing outer ring are usually fixed with an interference fit, requiring hydraulic equipment for forceful pulling during maintenance.

[0004] However, the current traditional universal joint device has many problems. First, because the rollers directly contact the cross shaft, the cross shaft body must be made of expensive low-carbon alloy steel and undergo carburizing and quenching. This not only results in high manufacturing costs and long production cycles, but also means that once surface indentations or peeling occur, the number of repairs is extremely limited, leading to high maintenance costs. Second, the sliding friction method using copper alloy gaskets in the axial direction is prone to wear, causing the axial clearance to increase, which in turn leads to abnormal noise and vibration during operation. Third, the sealing lip is located on the arc surface of the shaft end, and manufacturing errors make it difficult to control the sealing pressure, resulting in unstable sealing performance, easy lubrication failure, and shortened lifespan. Finally, the interference fit structure makes assembly and disassembly extremely inconvenient, and the mating surfaces are prone to wear during assembly and disassembly, seriously affecting assembly accuracy. Summary of the Invention

[0005] Therefore, it is necessary to provide a universal joint and universal coupling to address the above problems.

[0006] This application provides a universal joint, including a fork head assembly, a cross shaft assembly, and a bearing sleeve assembly. The fork head assemblies are arranged in pairs, and a pair of fork head assemblies are rotatably connected to the cross shaft assembly through the bearing sleeve assembly. The cross shaft assembly includes a cross shaft and a bearing inner ring sleeved on the shaft head of the cross shaft. The bearing sleeve assembly is sleeved on the bearing inner ring and nested in the bearing hole of the fork assembly. The bearing hole is provided with a first oil groove, and the fork head is provided with a first oil injection hole. The first oil injection hole is connected to the first oil groove and is used to inject oil into the first oil groove and form an oil film on the inner wall of the bearing hole to facilitate the disassembly of the bearing sleeve assembly.

[0007] Optionally, the cross shaft has a second oil groove on its outer edge and a second oil injection hole on its outer edge. The second oil injection hole is connected to the second oil groove and is used to inject oil into the second oil groove and form an oil film on the outer edge sidewall of the cross shaft to facilitate the disassembly of the bearing inner ring.

[0008] Optionally, each shaft head of the cross shaft is provided with a central hole for improving the strength of the shaft core, and each shaft head of the cross shaft is provided with a plurality of second oil injection holes, which are arranged around the central hole and respectively connected to the second oil groove on the shaft head.

[0009] Optionally, a plurality of the second oil injection holes are arranged at equal intervals around the central hole.

[0010] Optionally, the bearing sleeve assembly is provided with an anti-rotation key, and the bearing hole of the fork head is provided with an anti-rotation keyway on the outside, which is used to cooperate with the bearing sleeve assembly to limit the rotation of the bearing end cap in the bearing sleeve assembly.

[0011] Optionally, the bearing sleeve assembly includes a bearing outer ring, a bearing end cap, and rollers. The bearing outer ring and the bearing end cap together enclose a space suitable for accommodating the rollers, and are rotatably connected to the bearing inner ring through the rollers.

[0012] Optionally, the bearing sleeve assembly further includes a planar bearing disposed inside the bearing end cover. The planar bearing includes a cage and rolling elements. The rolling elements are disposed in the holes of the cage and are rotatably connected to the cage to reduce friction between the bearing sleeve assembly and the cross shaft assembly.

[0013] Optionally, the bearing sleeve assembly further includes a seal, which includes a main sealing ring, a sealing gland, and a secondary sealing ring. The main sealing ring is installed in a sealing groove at the end of the outer ring of the bearing. The sealing gland is fixed to the end face of the outer ring of the bearing. The secondary sealing ring is installed in the inner ring groove of the sealing gland. The mounting surfaces of the lips of the main sealing ring and the secondary sealing ring are both cylindrical surfaces.

[0014] Optionally, the bearing end cover, the bearing inner ring, and the shaft end of the cross shaft together form a cavity for containing oil, and the bearing end cover is provided with an oil filling hole for injecting oil into the cavity.

[0015] Optionally, the first and second oil injection holes are provided with screw plugs.

[0016] Optionally, the cross shaft is an alloy steel cross shaft that has undergone quenching and tempering treatment; the inner ring of the bearing is a low-carbon alloy steel bearing inner ring that has undergone carburizing and quenching treatment; and the outer ring of the bearing is a low-carbon alloy steel bearing outer ring that has undergone carburizing and quenching treatment.

[0017] This application also provides a universal coupling, including the aforementioned universal joint.

[0018] Compared with the prior art, the technical solution provided in this application has the following advantages: The aforementioned universal joint mainly comprises a pair of fork head assemblies, a cross shaft assembly, and a bearing sleeve assembly connecting the two. In specific assembly, the core of the cross shaft assembly lies in the fact that each end of the cross shaft is fitted with an independent bearing inner ring, and the bearing sleeve assembly is further fitted outside the bearing inner ring, integrally embedded in the bearing hole of the fork head assembly. To solve the disassembly difficulties caused by the interference fit, this embodiment has a first oil groove machined on the inner wall of the bearing hole of the fork head assembly, and a first oil injection hole communicating with the oil groove is provided inside the fork head. When it is necessary to disassemble the bearing sleeve assembly, maintenance personnel can inject high-pressure oil into the first oil groove through the first oil injection hole. The oil quickly forms an oil film between the inner wall of the bearing hole and the outer surface of the bearing sleeve assembly. This oil film plays a crucial lubricating role during assembly or disassembly, significantly reducing the coefficient of friction between the mating surfaces and effectively preventing scratches or seizing between the metal surfaces. Simultaneously, the presence of the oil film also prevents the mating surfaces from rusting and sticking under long-term static conditions or harsh working conditions, thus making the disassembly and maintenance of the bearing sleeve assembly easier and smoother. Attached Figure Description

[0019] Figure 1 An exploded three-dimensional structural diagram of a universal joint provided in an embodiment of this application; Figure 2 A three-dimensional structural schematic diagram of a fork assembly provided in an embodiment of this application; Figure 3 A cross-sectional structural schematic diagram of a fork assembly provided in an embodiment of this application; Figure 4 A three-dimensional structural schematic diagram of a cross shaft assembly provided in an embodiment of this application; Figure 5 A perspective structural schematic diagram of a cross shaft assembly provided in an embodiment of this application; Figure 6 A cross-sectional structural diagram of a cross shaft provided in an embodiment of this application; Figure 7A three-dimensional structural schematic diagram (first view) of a bearing sleeve assembly provided in an embodiment of this application; Figure 8 A three-dimensional structural schematic diagram of a bearing sleeve assembly provided in an embodiment of this application (second view, showing the rollers and internal structure). Figure 9 This is a schematic diagram of the structure of a planar bearing provided in an embodiment of this application; Figure 10 This is a cross-sectional structural diagram of a bearing sleeve assembly provided in an embodiment of this application.

[0020] Explanation of reference numerals in the attached figures: 1. Fork head assembly; 2. Cross shaft assembly; 3. Bearing sleeve assembly; 11. First oil groove; 12. First oil filling hole; 13. Anti-rotation keyway; 21. Cross shaft; 22. Bearing inner ring; 31. Anti-rotation key; 32. Bearing outer ring; 33. Bearing end cap; 34. Roller; 35. Surface bearing; 36. Seal; 211. Second oil groove; 212. Second oil filling hole; 213. Center hole; 331. Oil filling hole; 351. Cage; 352. Rolling element; 361. Main seal ring; 362. Sealing gland; 363. Secondary seal ring. Detailed Implementation

[0021] To make the above-mentioned objects, features, and advantages of the present invention more apparent and understandable, specific embodiments of the present invention will be described in detail below with reference to the accompanying drawings. Many specific details are set forth in the following description to provide a thorough understanding of the present invention. However, the present invention can be practiced in many other ways different from those described herein, and those skilled in the art can make similar modifications without departing from the spirit of the present invention. Therefore, the present invention is not limited to the specific embodiments disclosed below.

[0022] See Figures 1 to 4 An embodiment of the present invention provides a universal joint, including a fork head assembly 1, a cross shaft assembly 2, and a bearing sleeve assembly 3. The fork head assemblies 1 are arranged in pairs, and the pair of fork head assemblies 1 are rotatably connected to the cross shaft assembly 2 through the bearing sleeve assembly 3. The cross shaft assembly 2 includes a cross shaft 21 and a bearing inner ring 22 sleeved on the shaft head of the cross shaft 21. The bearing sleeve assembly 3 is sleeved on the bearing inner ring 22 and nested in the bearing hole of the fork head assembly 1. A first oil groove 11 is provided in the bearing hole, and a first oil injection hole 12 is provided on the fork head. The first oil injection hole 12 is connected to the first oil groove 11 and is used to inject oil into the first oil groove 11 to form an oil film on the inner wall of the bearing hole.

[0023] See Figure 2 and Figure 3The universal joint provided in this embodiment mainly includes a pair of fork head assemblies 1, a cross shaft assembly 2, and a bearing sleeve assembly 3 connecting the two. In specific assembly, the core of the cross shaft assembly 2 is that each end of the cross shaft 21 is fitted with an independent bearing inner ring 22, and the bearing sleeve assembly 3 is further fitted outside the bearing inner ring 22, and is integrally embedded in the bearing hole of the fork head assembly 1. To solve the disassembly difficulties caused by the interference fit, this embodiment has a first oil groove 11 machined on the inner wall of the bearing hole of the fork head assembly 1, and a first oil injection hole 12 communicating with the oil groove is provided inside the fork head. When it is necessary to disassemble the bearing sleeve assembly 3, maintenance personnel can inject high-pressure oil into the first oil groove 11 through the first oil injection hole 12. The oil quickly forms an oil film between the inner wall of the bearing hole and the outer surface of the bearing sleeve assembly 3. This oil film plays a key lubricating role during assembly or disassembly, significantly reducing the coefficient of friction between the mating surfaces and effectively preventing scratches or seizing between the metal surfaces. At the same time, the presence of the oil film can also prevent the mating surfaces from rusting and sticking under long-term static conditions or harsh working conditions, thus making the disassembly and maintenance of the bearing sleeve assembly 3 easier and smoother.

[0024] See Figure 5 and Figure 6 In one embodiment, a second oil groove 211 is provided on the outer edge of the shaft head of the cross shaft 21, and a second oil injection hole 212 is provided on the cross shaft 21. The second oil injection hole 212 is connected to the second oil groove 211 and is used to inject oil into the second oil groove 211 to form an oil film on the outer edge sidewall of the shaft head of the cross shaft 21. This embodiment is a further improvement based on the aforementioned embodiments. In the structure of the cross shaft assembly 2, a second oil groove 211 is formed on the outer edge surface of the shaft head of the cross shaft 21, and a second oil injection hole 212 is provided inside the cross shaft 21. The oil injection hole penetrates the body of the cross shaft 21 and communicates with the second oil groove 211. For the tight fit interface between the shaft head of the cross shaft 21 and the inner ring 22 of the bearing, oil is injected through the second oil injection hole 212 to form a lubricating oil film on the second oil groove 211 and the outer edge sidewall of the shaft head. This oil film isolates the cross shaft 21 from direct rigid contact with the bearing inner ring 22. It not only reduces the pressing resistance during initial assembly, but more importantly, when the worn inner ring needs to be replaced after long-term operation of the equipment, this oil film can effectively eliminate the "cold welding" or deadlock effect caused by fretting wear or corrosion, ensuring that the inner ring can be smoothly removed mechanically, avoiding damage to the expensive surface of the cross shaft 21 caused by forced disassembly.

[0025] See Figure 5 and Figure 6In one embodiment, each end of the cross shaft 21 is provided with a central hole 213 for connecting the bearing sleeve assembly 3, and each end of the cross shaft 21 is provided with a plurality of second oil injection holes 212. The plurality of second oil injection holes 212 are arranged around the central hole 213 and are respectively connected to the second oil groove 211 on the shaft end. This embodiment further refines the oil passage structure of the cross shaft 21. At the center of the end face of each end of the cross shaft 21, there is a central hole 213 for connecting the bearing sleeve assembly 3 or serving as an oil passage inlet. Around the central hole 213, a plurality of second oil injection holes 212 are opened inside the shaft end. One end of these second oil injection holes 212 communicates with the central hole 213 or an external oil source interface, and the other end extends to the second oil groove 211 on the surface of the shaft end. Through the cooperation of the central hole 213 and the plurality of second oil injection holes 212, a highly efficient flow-diverting oil passage system is constructed. The multi-hole flow-diverting design optimizes the delivery efficiency and coverage of the lubricating oil. Compared to single-hole oil injection, several second oil injection holes 212 arranged around the central hole 213 ensure that the oil is filled into the second oil groove 211 on the shaft end surface more quickly and comprehensively. This ensures that a continuous lubricating oil film can be quickly established throughout the entire mating circumference, avoiding local dry friction or lubrication blind spots, thereby maximizing the rust prevention and friction reduction effects of the oil film.

[0026] See Figure 5 In one embodiment, a plurality of second oil injection holes 212 are arranged at equal intervals around the central hole 213. This embodiment is an optimization of the oil injection hole layout in the aforementioned embodiments. The plurality of second oil injection holes 212 are arranged radially or annularly at equal intervals around the cross-section of the shaft head, with the central hole 213 of the cross shaft 21 as a reference. This geometrically symmetrical distribution ensures the uniformity of lubricating oil distribution in the circumferential direction of the shaft head. When oil is injected, the equally spaced oil injection holes allow the oil to reach each sector of the shaft head surface simultaneously, promoting a uniform lubricating oil film thickness. A uniform oil film not only provides stable rust protection but also provides a uniform lubrication interface during disassembly, preventing tilting or jamming of the inner ring during disassembly due to excessive local friction, further improving the convenience and reliability of maintenance operations.

[0027] See Figure 2 and Figure 8In one embodiment, the bearing sleeve assembly 3 is provided with an anti-rotation key 31, and the outer side of the bearing hole of the fork head is provided with an anti-rotation keyway 13, which is used to cooperate with the bearing sleeve assembly 3 to limit the rotation of the bearing sleeve assembly 3. This embodiment relates to an anti-rotation positioning structure for the bearing sleeve assembly 3. The bearing sleeve assembly 3 is provided with an anti-rotation key 31, and correspondingly, an anti-rotation keyway 13 is formed on the outer end face of the bearing hole of the fork head. When the bearing sleeve assembly 3 is installed in place, the anti-rotation key 31 is simultaneously embedded in the keyway of both the bearing sleeve assembly 3 and the fork head. The anti-rotation key 31 provides a rigid mechanical locking function, which can reliably withstand the tangential force generated by the universal joint under heavy load and high-speed operation conditions, completely eliminating the risk of circumferential rotation of the bearing sleeve assembly 3 relative to the fork head, preventing wear caused by relative sliding of the mating surfaces, and ensuring the stability of power transmission.

[0028] See Figure 8 and Figure 10 In one embodiment, the bearing sleeve assembly 3 includes a bearing outer ring 32, a bearing end cap 33, and rollers 34. The bearing outer ring 32 and the bearing end cap 33 together enclose a space suitable for accommodating the rollers 34, and the rollers 34 are rotatably connected to the bearing inner ring 22. This embodiment describes the modular configuration of the bearing sleeve assembly 3. The bearing sleeve assembly 3 includes a bearing outer ring 32, a bearing end cap 33, and rollers 34. The bearing outer ring 32 and the bearing end cap 33 together enclose a closed internal space, in which the rollers 34 are accommodated and rotatably connected to the bearing inner ring 22. By encapsulating the rollers 34 in a separate assembly and isolating the inner surface of the rolling friction pair (bearing inner ring 22), the cross shaft 21 body no longer directly bears the wear of the rollers 34. This design not only simplifies the on-site assembly process but also reduces the material requirements for the cross shaft 21 body, eliminating the need for extremely high surface hardness and significantly reducing manufacturing costs.

[0029] See Figure 9 and Figure 10In one embodiment, the bearing sleeve assembly 3 further includes a planar bearing 35 disposed inside the bearing end cover 33. The planar bearing 35 includes a cage 351 and rolling elements 352. The rolling elements 352 are disposed in the hole of the cage 351 and are rotatably connected to the cage 351 to reduce the friction between the bearing sleeve assembly 3 and the cross shaft assembly 2. This embodiment adds a planar bearing 35 structure to the aforementioned embodiment. A planar bearing 35 is disposed inside the bearing end cover 33. The planar bearing 35 includes a cage 351 and rolling elements 352 installed in the hole of the cage 351. These rolling elements 352 are rotatably connected to the cage 351 and roll inside the end cover, upgrading the friction mode of the universal joint's axial force point from traditional sliding friction to rolling friction. This change significantly reduces the frictional resistance of the universal joint when bearing axial loads and oscillations, solves the problem of increased axial clearance caused by easy wear of traditional shims, thereby eliminating abnormal noise and vibration during universal joint operation and extending the overall service life.

[0030] See Figure 10 In the aforementioned bearing sleeve assembly 3, to further optimize the transmission of axial load and reduce friction, the planar bearing 35 located inside the bearing end cover 33 employs a multi-layer composite structure. Specifically, the planar bearing 35 includes not only a cage 351 and rolling elements 352, but also a first wear-resistant pad, a second wear-resistant pad, and a buffer pad. The first wear-resistant pad is located on the side of the cage 351 near the cross shaft assembly 2, directly bearing the axial thrust from the shaft head of the cross shaft 21; the second wear-resistant pad is located on the side of the cage 351 near the bearing end cover 33. The rolling elements 352 (preferably needle rollers or rollers 34) on the cage 351 are held between the first and second wear-resistant pads and roll. This structural design completely transforms the relative motion between the bearing sleeve assembly 3 and the cross shaft assembly 2 from traditional sliding friction to rolling friction, significantly reducing operating resistance and heat generation. In addition, a buffer pad (which can be made of polymer material or elastic metal material) is also provided between the second wear-resistant pad and the inner bottom surface of the bearing end cover 33. This buffer pad provides axial flexibility to the rigid bearing system, effectively absorbing high-frequency vibrations and axial impact loads generated during the variable-angle transmission of the universal joint, preventing crushing or peeling of the precision raceway surface, thereby significantly extending the service life of the bearing sleeve assembly 3. To ensure installation accuracy, a special mounting groove for the flat bearing 35 is provided on the inner end face of the bearing end cover 33, ensuring that the flat bearing 35 assembly is perpendicular to the axis of the cross shaft 21 and avoiding off-center loading.

[0031] See Figure 8 and Figure 10In one embodiment, the bearing sleeve assembly 3 further includes a seal 36, which includes a main sealing ring 361, a sealing gland 362, and a secondary sealing ring 363. The main sealing ring 361 is installed in a sealing groove at the end of the bearing outer ring 32, the sealing gland 362 is fixed to the end face of the bearing outer ring 32, and the secondary sealing ring 363 is installed in the inner annular groove of the sealing gland 362. The mounting surfaces of the lips of both the main sealing ring 361 and the secondary sealing ring 363 are cylindrical. This embodiment details the sealing structure. The bearing sleeve assembly 3 is equipped with a seal 36, which includes a main sealing ring 361 installed in a sealing groove at the end of the bearing outer ring 32, a sealing gland 362 fixed to the end face of the outer ring, and a secondary sealing ring 363 installed in the inner annular groove of the gland. The lips of both the main seal ring 361 and the auxiliary seal ring 363 are mounted on a cylindrical surface (i.e., the outer cylindrical surface of the bearing inner ring 22). Utilizing the standard cylindrical surface provided by the bearing inner ring 22 as the sealing mating surface overcomes the defect of inadequate sealing on the arc surface at the root of the cross shaft 21 in traditional technologies. Combined with the main and auxiliary dual-seal design, this greatly improves the reliability of the sealing system, effectively preventing internal lubricant leakage and external impurity intrusion, thus ensuring the long-term operation of the bearing.

[0032] See Figure 10 The aforementioned bearing sleeve assembly 3 employs a dual sealing system combining a main sealing ring 361 and a secondary sealing ring 363 to adapt to harsh working conditions. The main sealing ring 361 (preferably a skeleton oil seal) is installed in a sealing groove on the inner wall of the end of the bearing outer ring 32. Its main function is to seal the internal cavity of the bearing sleeve assembly 3 and prevent grease leakage under centrifugal force. The sealing cap 362 is fixed to the end face of the bearing outer ring 32, and a secondary sealing ring 363 (preferably a dustproof ring) is installed in its inner ring groove to prevent external dust, mud, water, and impurities from entering. It is particularly noteworthy that, unlike the prior art where the sealing lip is pressed against the arc surface at the root of the cross shaft 21, in this embodiment, the sealing lips of both the main sealing ring 361 and the secondary sealing ring 363 directly abut against the outer cylindrical surface of the bearing inner ring 22. Because the bearing inner ring 22 is precision machined, its outer cylindrical surface has extremely high roundness and surface finish, and there is no curvature change caused by arc surface machining errors. Therefore, the contact pressure of the sealing lip in the circumferential direction is uniform and constant. Combined with the dual mechanism of internal oil sealing and external dust prevention, the reliability of the sealing system is greatly improved, ensuring that the rollers 34 and the flat bearing 35 inside the bearing sleeve assembly 3 are always in a clean and well-lubricated working environment.

[0033] See Figure 10In one embodiment, the bearing end cap 33, the bearing inner ring 22, and the shaft end of the cross shaft 21 together form a cavity for containing oil. The bearing end cap 33 is provided with an oil filling hole 331 for injecting oil into the cavity. In this embodiment, the bearing end cap 33, the bearing inner ring 22, and the shaft end of the cross shaft 21 together form an internal cavity capable of containing oil, which is spatially connected to the second oil filling hole 212. The bearing end cap 33 is provided with a dedicated oil filling hole 331 for injecting lubricating oil or grease into the cavity. The oil filling hole 331 is the inlet of the lubricating medium. The injected lubricating oil fills the entire cavity and the internal space of the second oil filling hole 212, etc. Its function is to wet and lubricate the rolling elements 352, rollers 34, and cage 351 of the planar bearing 35, so as to reduce the coefficient of friction, reduce wear, and assist in heat dissipation. The lubricating grease flows through the rollers 34 and is discharged from the spherical bearing through the seal 36.

[0034] See Figure 3 and Figure 6 In one embodiment, the first oil injection hole 12 and the second oil injection hole 212 are provided with screw plugs. During normal operation of the universal joint, the screw plugs serve to seal and prevent dust, preventing internal lubricating oil leakage and preventing external dust from entering the high-pressure oil circuit. At the same time, the presence of the screw plugs clearly distinguishes between the working state and the maintenance state—the screw plugs are only removed to connect the high-pressure oil pipes when disassembly is required, while in daily operation, the screw plugs ensure the sealing of the oil circuit, preventing the lubricating oil from leaking from the high-pressure oil injection holes.

[0035] See Figure 1 In one embodiment, the cross shaft 21 is made of tempered alloy steel; the bearing inner ring 22 is made of carburized and quenched low-carbon alloy steel; and the bearing outer ring 32 is made of carburized and quenched low-carbon alloy steel. This embodiment optimizes the materials and heat treatment processes of key components. The cross shaft 21 body is made of tempered alloy steel, while the bearing inner ring 22 and bearing outer ring 32 are made of carburized and quenched low-carbon alloy steel. Due to the introduction of the bearing inner ring 22, the cross shaft 21 body no longer directly bears high-intensity contact fatigue stress; therefore, only tempering is needed to meet the strength requirements, avoiding the complex carburizing and quenching process and significantly reducing costs and manufacturing risks. Conversely, the bearing inner ring 22 and outer ring, which directly bear rolling friction, achieve extremely high surface hardness through carburizing and quenching, ensuring the universal joint's load-bearing capacity and wear resistance.

[0036] An embodiment of the present invention also provides a universal coupling, including the aforementioned universal joint. The universal coupling provided in this embodiment combines the advantages of easy disassembly, long service life, and low maintenance costs. In particular, the design separating the lubrication system from the disassembly system ensures both good lubrication (low-pressure lubrication) during equipment operation and convenient disassembly during maintenance, significantly reducing downtime for heavy machinery maintenance and improving production efficiency.

[0037] The technical features of the above embodiments can be combined in any way. For the sake of brevity, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0038] The embodiments described above are merely illustrative of several implementations of the present invention, and while the descriptions are relatively specific and detailed, they should not be construed as limiting the scope of the invention patent. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of the present invention, and these all fall within the protection scope of the present invention. Therefore, the protection scope of this invention patent should be determined by the appended claims.

Claims

1. A universal joint, comprising a fork assembly (1), a cross shaft (21) assembly (2), and a bearing sleeve assembly (3), wherein the fork assemblies (1) are arranged in pairs, and a pair of fork assemblies (1) are rotatably connected to the cross shaft (21) assembly (2) via the bearing sleeve assembly (3), characterized in that, The cross shaft (21) assembly (2) includes a cross shaft (21) and a bearing inner ring (22) sleeved on the shaft head of the cross shaft (21). The bearing sleeve assembly (3) is sleeved on the bearing inner ring (22) and nested in the bearing hole of the fork assembly (1). The bearing hole is provided with a first oil groove (11). The fork head is provided with a first oil injection hole (12). The first oil injection hole (12) is connected to the first oil groove (11) and is used to inject oil into the first oil groove (11) and form an oil film on the inner wall of the bearing hole to facilitate the disassembly of the bearing sleeve assembly (3).

2. The universal joint according to claim 1, characterized in that, The cross shaft (21) has a second oil groove (211) on the outer edge of the shaft head and a second oil injection hole (212) on the cross shaft (21). The second oil injection hole (212) is connected to the second oil groove (211) and is used to inject oil into the second oil groove (211) and form an oil film on the side wall of the outer edge of the shaft head of the cross shaft (21) to facilitate the disassembly of the bearing inner ring (22).

3. The universal joint according to claim 1, characterized in that, Each shaft head of the cross shaft (21) is provided with a central hole (213) for improving the strength of the shaft core. Each shaft head of the cross shaft (21) is provided with a plurality of second oil injection holes (212). The plurality of second oil injection holes (212) are arranged around the central hole (213) and are respectively connected to the second oil groove (211) on the shaft head.

4. The universal joint according to claim 3, characterized in that, A plurality of second oil injection holes (212) are arranged at equal intervals around the central hole (213).

5. The universal joint according to claim 1, characterized in that, The bearing sleeve assembly (3) is provided with an anti-rotation key (31), and the bearing hole of the fork head is provided with an anti-rotation key (31) groove (13) for cooperating with the bearing sleeve assembly (3) to limit the rotation of the bearing end cap (33) in the bearing sleeve assembly (3).

6. The universal joint according to claim 1, characterized in that, The bearing sleeve assembly (3) includes a bearing outer ring (32), a bearing end cap (33) and rollers (34). The bearing outer ring (32) and the bearing end cap (33) together enclose a space suitable for accommodating the rollers (34), and are rotatably connected to the bearing inner ring (22) through the rollers (34).

7. The universal joint according to claim 6, characterized in that, The bearing sleeve assembly (3) further includes a planar bearing (35) disposed inside the bearing end cover (33). The planar bearing (35) includes a cage (351) and rolling elements (352). The rolling elements (352) are disposed in the hole of the cage (351) and are rotatably connected to the cage (351) to reduce the friction between the bearing sleeve assembly (3) and the cross shaft (21) assembly (2).

8. The universal joint according to claim 1, characterized in that, The bearing sleeve assembly (3) further includes a seal (36), which includes a main seal ring (361), a sealing gland (362), and a secondary seal ring (363). The main seal ring (361) is installed in the sealing groove at the end of the outer ring (32) of the bearing. The sealing gland (362) is fixed on the end face of the outer ring (32) of the bearing. The secondary seal ring (363) is installed in the inner ring groove of the sealing gland (362). The mounting surfaces of the lips of the main seal ring (361) and the secondary seal ring (363) are both cylindrical surfaces.

9. The universal joint according to claim 6, characterized in that, The bearing end cap (33), the bearing inner ring (22), and the shaft head of the cross shaft (21) together form a cavity for containing oil. The bearing end cap (33) is provided with an oil filling hole (331) for injecting oil into the cavity.

10. The universal joint according to claim 1, characterized in that, The first oil injection hole (12) and the second oil injection hole (212) are provided with screw plugs.

11. The universal joint according to claim 1, characterized in that, The cross shaft (21) is an alloy steel cross shaft (21) that has undergone quenching and tempering treatment; the bearing inner ring (22) is a low-carbon alloy steel bearing inner ring (22) that has undergone carburizing and quenching treatment; the bearing outer ring (32) is a low-carbon alloy steel bearing outer ring (32) that has undergone carburizing and quenching treatment.

12. A universal coupling, characterized in that, Includes the universal joint according to any one of claims 1-11.

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