Duplex universal joint transmission shaft with oil injection structure

Abstract

The invention relates to a duplex universal joint transmission shaft with an oil injection structure, and belongs to the technical field of steering driving. The universal joint comprises a short shaft fork, a duplex fork and a long shaft fork, the two ends of the duplex fork are connected with the short shaft fork and the long shaft fork through universal joint assemblies respectively, each universal joint assembly comprises a cross shaft, a bearing and a clamping spring, the bearings are installed on the cross shafts, the closed ends of the bearings are connected to the short shaft fork, the duplex fork and the long shaft fork in a clamped mode through the clamping springs, and the short shaft fork and the long shaft fork are connected through the universal joint assemblies. The structure is characterized in that an oil injection nozzle is further included, the oil injection nozzle is installed on the duplex fork, the duplex fork is provided with an oil injection channel and an oil injection ring groove, the oil injection nozzle is communicated with the oil injection channel, the oil injection channel is communicated with the oil injection ring groove, the oil injection ring groove is communicated with the interior of the bearing, and the cross shaft is sleeved with an oil seal. And the oil seal is arranged at the open end of the bearing.

Description

Technical Field

[0001] The invention relates to a double universal joint transmission shaft with an oil injection structure, belonging to the technical field of steering drive. Background Art

[0002] A double-jointed universal joint drive shaft usually includes a short-shaft fork 1, a double-jointed fork 2, a long-shaft fork 3, a universal joint assembly and other structures. The short-shaft fork 1 and the long-shaft fork 3 are respectively installed at the two ends of the double-jointed fork 2 through the universal joint assembly, so that the short-shaft fork 1 and the long-shaft fork 3 are not on the same axis, and transmission is performed when there is an angle between the short-shaft fork 1 and the long-shaft fork 3; in view of this, a large-angle steering drive axle half-shaft assembly is disclosed in the patent document with application number 202223293355.3, and a cross universal joint drive shaft and its retaining spring locking mechanism are disclosed in the patent document with application number 202122377438.X. The drive shafts in the above-mentioned prior art do not have an oil injection structure; at the same time, the outer sides of most of the double-jointed forks 2 are curved surfaces, and no flat surface can be found, which makes it easy for the bearing to be reversed during the installation process; and no middle boss 61 is provided on the retaining spring 6, and it is impossible to quickly identify whether the retaining spring 6 is stuck in the slot during assembly. Summary of the Invention

[0003] The purpose of the present invention is to overcome the above-mentioned deficiencies in the prior art and to provide a double universal joint transmission shaft with an oil injection structure that has a rational structural design.

[0004] The technical solution adopted by the present invention to solve the above-mentioned problem is: the double universal joint transmission shaft with an oil injection structure includes a short shaft fork, a double fork and a long shaft fork, and the two ends of the double fork are respectively connected to the short shaft fork and the long shaft fork through a universal joint assembly. The universal joint assembly includes a cross shaft, a bearing and a retaining spring. The bearing is installed on the cross shaft, and the closed end of the bearing is clamped on the short shaft fork, the double fork and the long shaft fork through a retaining spring. Its structural feature is that it also includes an oil injection nozzle, which is installed on the double fork, and the double fork is provided with an oil injection channel and an oil injection ring groove. The oil injection nozzle is connected to the oil injection channel, the oil injection channel is connected to the oil injection ring groove, and the oil injection ring groove is connected to the interior of the bearing.

[0005] Furthermore, an oil seal is mounted on the cross shaft, and the oil seal is arranged at the open end of the bearing.

[0006] Furthermore, a stub fork slot is provided on the stub fork, and the retaining spring is located in the stub fork slot.

[0007] Furthermore, a double fork slot is provided on the double fork, and the retaining spring is located in the double fork slot.

[0008] Furthermore, a long axis fork slot is provided on the long axis fork, and the retaining spring is located in the long axis fork slot.

[0009] Furthermore, the cross shaft includes a shaft seat, a shaft head and an oil injection channel. Four shaft heads are provided on the shaft seat, and the four shaft heads are arranged in a cross-shaped structure. An oil injection channel is provided inside each of the four shaft heads, and the oil injection channels are interconnected. The bearing sleeve is mounted on the shaft head.

[0010] Furthermore, the bearing includes an outer ring, a needle roller and an oil injection hole. The outer ring is mounted on the shaft head. The needle roller is arranged between the inner wall of the outer ring and the outer wall of the shaft head. The oil injection hole is arranged on the side wall of the outer ring. The oil injection ring groove is connected to the oil injection hole.

[0011] Furthermore, a central boss and two side bosses are provided on the inner side of the retaining spring, and the two side bosses are symmetrically arranged with respect to the central boss.

[0012] Furthermore, the double fork is provided with an assembly countersunk hole.

[0013] Furthermore, a mounting groove for mounting an oiling nozzle is provided on the double fork, and the oiling nozzle is located in the mounting groove.

[0014] Compared with the existing technology, the present invention has the following advantages: the double universal joint drive shaft with oil injection structure can avoid the occurrence of bearing back-stitching during the assembly process by arranging assembly countersunk holes on the double fork, thereby reducing the assembly scrap and rework rate. The structural design of the countersunk hole surface allows the assembly tooling to accurately position the countersunk hole surface, achieving smooth assembly and effectively controlling product quality.

[0015] The double universal joint transmission shaft with oil injection structure has a middle boss set in the middle of the retaining spring and an outer ring countersunk hole on the top surface of the outer ring. When the retaining spring is used to fix and assemble the bearing, the diameter of the circle formed by the middle boss and the two side bosses can be compared with the diameter of the outer ring countersunk hole to identify whether the retaining spring is completely ejected after assembly.

[0016] The design principle is set so that the diameter of the circle formed by the center boss and the two side bosses of the retaining spring after assembly is greater than or equal to the diameter of the outer ring countersunk circle, but at the same time, matching design calculations are performed. When the retaining spring is not fully ejected, the diameter of the circle formed by the center boss and the two side bosses of the retaining spring is smaller than the diameter of the outer ring countersunk circle. The above two boundaries are used to identify whether the retaining spring is fully ejected after assembly; or when the state of the center boss or any position of the two side bosses of the retaining spring after assembly is compared with the outer ring countersunk circle, if it is smaller than the position of the outer ring countersunk circle, it also means that the retaining spring is not fully ejected. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1 It is a schematic three-dimensional structural diagram of a double universal joint transmission shaft with an oil injection structure according to an embodiment of the present invention.

[0018] Figure 2 2 is a schematic cross-sectional structural diagram of a double fork according to an embodiment of the present invention.

[0019] Figure 3 It is a schematic cross-sectional structural diagram of a universal joint assembly according to an embodiment of the present invention.

[0020] Figure 4 It is a schematic diagram of the main structure of a double universal joint transmission shaft with an oil injection structure according to an embodiment of the present invention.

[0021] Figure 5 yes Figure 4 Schematic diagram of the local enlarged structure of AA.

[0022] Figure 6 2 is a schematic cross-sectional structural diagram of a short-axle fork according to an embodiment of the present invention.

[0023] Figure 7 It is a schematic cross-sectional structure diagram of the long-axis fork according to an embodiment of the present invention.

[0024] Figure 8 It is a schematic diagram of a partial cross-sectional structure of a universal joint assembly according to an embodiment of the present invention.

[0025] Figure 9 It is a schematic diagram of the installation structure of the retaining spring according to an embodiment of the present invention.

[0026] In the figure: short shaft fork 1, double fork 2, long shaft fork 3, cross shaft 4, bearing 5, retaining ring 6, oil injection nozzle 7, oil seal 8, Short shaft fork slot 11, Double fork slot 21, oil injection channel 22, oil injection ring groove 23, assembly countersunk hole 24, Long axis fork slot 31, Shaft seat 41, shaft head 42, oil injection channel 43, Outer ring 51, needle roller 52, oil injection hole 53, outer ring countersunk hole 54, Middle boss 61 and side boss 62 . DETAILED DESCRIPTION

[0027] The present invention will be further described in detail below with reference to the accompanying drawings and through examples. The following examples are intended to explain the present invention but the present invention is not limited to the following examples.

[0028] Example

[0029] See also Figures 1 to 9As shown, it should be noted that the structures, proportions, sizes, etc. illustrated in the drawings of this specification are only used to match the contents disclosed in the specification for people familiar with this technology to understand and read, and are not used to limit the limiting conditions for the implementation of the present invention. Therefore, they have no substantial technical significance. Any modification of the structure, change in the proportional relationship or adjustment of the size should still fall within the scope of the technical content disclosed by the present invention without affecting the efficacy and purpose that can be achieved by the present invention. At the same time, if there are references to terms such as "upper", "lower", "left", "right", "middle" and "one" in this specification, they are only for the convenience of description and are not used to limit the scope of the implementation of the present invention. Changes or adjustments in their relative relationships should also be regarded as the scope of the implementation of the present invention without substantially changing the technical content.

[0030] The double universal joint drive shaft with an oil injection structure in this embodiment includes a short shaft fork 1, a double fork 2, a long shaft fork 3 and an oil injection nozzle 7. The two ends of the double fork 2 are respectively connected to the short shaft fork 1 and the long shaft fork 3 through a universal joint assembly. The oil injection nozzle 7 is installed on the double fork 2, that is, the double fork 2 is provided with a mounting groove for installing the oil injection nozzle 7, and the oil injection nozzle 7 is located in the mounting groove.

[0031] The universal joint assembly in this embodiment includes a cross shaft 4, a bearing 5 and a retaining spring 6. The bearing 5 is mounted on the cross shaft 4. The closed end of the bearing 5 is clamped to the short shaft fork 1, the double fork 2 and the long shaft fork 3 through the retaining spring 6. The cross shaft 4 is provided with an oil seal 8, which is arranged at the open end of the bearing 5.

[0032] In this embodiment, that is to say, a short-axle fork slot 11 is provided on the short-axle fork 1, and the retaining spring 6 is located in the short-axle fork slot 11; a double-axle fork slot 21 is provided on the double-axle fork 2, and the retaining spring 6 is located in the double-axle fork slot 21; a long-axle fork slot 31 is provided on the long-axle fork 3, and the retaining spring 6 is located in the long-axle fork slot 31.

[0033] The double fork 2 in this embodiment is provided with an oil injection channel 22, an oil injection ring groove 23 and an assembly countersunk hole 24, the oil injection nozzle 7 is connected to the oil injection channel 22, the oil injection channel 22 is connected to the oil injection ring groove 23, and the oil injection ring groove 23 is connected to the interior of the bearing 5.

[0034] The cross shaft 4 in this embodiment includes a shaft seat 41, a shaft head 42 and an oil injection channel 43. Four shaft heads 42 are provided on the shaft seat 41. The four shaft heads 42 are arranged in a cross-shaped structure. An oil injection channel 43 is provided inside each of the four shaft heads 42. The oil injection channels 43 are interconnected, and the bearing 5 is mounted on the shaft head 42.

[0035] The bearing 5 in this embodiment includes an outer ring 51, a needle roller 52 and an oil injection hole 53. The outer ring 51 is mounted on the shaft head 42. The needle roller 52 is arranged between the inner wall of the outer ring 51 and the outer wall of the shaft head 42. The oil injection hole 53 is arranged on the side wall of the outer ring 51. The oil injection ring groove 23 is connected to the oil injection hole 53. An outer ring countersunk hole 54 is provided on the top surface of the outer ring 51.

[0036] In this embodiment, a central boss 61 and two side bosses 62 are provided on the inner side of the clamping spring 6 , and the two side bosses 62 are symmetrically arranged with respect to the central boss 61 .

[0037] During oiling, the lubricating oil is injected into the oil filling channel 22 through the oil filling nozzle 7 and enters the oil filling ring groove 23. The lubricating oil flows through the oil filling hole 53 and enters the interior of the outer ring 51, lubricating the needle rollers 52. At the same time, the lubricating oil flows into the oil filling channel 43, so that the needle rollers 52 outside each shaft head 42 can be lubricated.

[0038] Specifically, the double universal joint drive shaft with oil injection structure is mainly used in paddy field agricultural tractors. There is one on each side of the main reducer of the drive axle, which is used to connect the differential in the middle of the drive axle and the wheel-side reduction device at the outer end, and plays the function of transmitting power and steering; the universal joint drive shaft adopts a double universal joint structure, and each assembly consists of a long shaft fork 3, a short shaft fork 1, a double fork 2, and two sets of universal joint assemblies. This structural design enables the drive shaft angle to reach 61°.

[0039] The short-axle fork 1 is a device that integrates a sun gear and can achieve higher torque transmission requirements in the same space. That is, the rod is designed with a gear structure, the gear accuracy can reach national standards (or ISO standards) 5-7 levels, and the gear has tooth profile modification (such as drum shape or K type) and tooth direction modification (such as drum shape or taper); the high-precision gear short-axle fork 1 can directly engage with the planetary gear in the drive axle wheel side reducer for transmission, with high matching accuracy and long service life.

[0040] In the industry, the general short-axle fork 1 rod design is an external spline, which needs to be assembled with the sun gear with internal splines through splines before it can be used. There is an error in the spline matching of the two, which will reduce the gear meshing transmission accuracy between the sun gear on the short-axle fork and the planetary gear in the wheel-side reducer, and is prone to vibration, noise and heat, resulting in a reduced service life.

[0041] For the long-axis fork 3, in addition to the induction hardening treatment of the spline, bearing block, oil seal block and other parts, the transition fillet between the rod and the fork is also specially induction hardened. Not only is the entire transition fillet fully hardened (uniformly hardened in one circle), the depth of the hardened layer can reach 2-3mm, and the metallographic structure meets the national standard requirements (grades 3-7). In particular, there is no overheating or overburning in the thin wall near the transition fillet.

[0042] The common practice in the industry is not to perform induction hardening on the transition fillet. This is because the transition fillet itself is not easy to harden due to the external structure of the transition fillet. If hardening is required, the sensor needs to stay there for a relatively longer time, which can easily cause overheating and overburning of the thin-walled metal near the fillet. When the double-joint drive shaft is subjected to force, there is stress concentration at the transition fillet, which is a weak link of the double-joint drive shaft. Failure often occurs at this fillet during torsional fatigue testing. Therefore, hardening treatment at the transition fillet is of great help in improving the torsional fatigue life of the double-joint drive shaft.

[0043] The double fork 2 adopts a main body structure connected by an annular surface and a universal joint hole to form an integrated structure, realizing the assembly connection and torque transmission function between the short-axis fork 1 and the long-axis fork 3. The outside of the mounting hole of the universal joint assembly is designed with an assembly countersunk hole 24 for achieving assembly stability.

[0044] A double universal joint drive shaft with an oil injection structure, that is, an oil injection channel 22 and an oil injection ring groove 23 are designed on the double fork 2, which can be used to inject oil for the maintenance of the universal joint assembly. The oil injection nozzle 7 can have a single oil nozzle or a double oil nozzle structure. The single oil nozzle is designed with a mounting groove at the center position of one side of the double fork 2, and an oil injection ring groove 23 is provided in the ear hole, and then the oil injection channel 22 and the mounting groove are connected. The double oil nozzle structure is that mounting grooves are provided at the center position of both sides of the double fork 2, and oil injection ring grooves 23 are provided on both sides of the ear holes.

[0045] High strength is mainly reflected in the following aspects: 1) The cross shaft of the universal joint assembly is made of high-quality alloy steel, and the structure of the cross shaft 4 adopts a low-stress design; 2) The bearing of the universal joint assembly adopts a cold-stamped bearing, that is, the outer ring of the bearing is manufactured by a cold-stamping process, and the wall thickness of the outer ring is close to 1mm, while the wall thickness of the outer ring of the bearing manufactured by the traditional hot forging process is about 2-3mm, and the difference between the two is 1-2mm. This difference gives the universal joint assembly using cold-stamped bearings obvious dimensional advantages in terms of the shaft head diameter and cross shaft length of the cross shaft.

[0046] For example, when the outer diameters of the bearings are the same, the inner diameter of the outer ring of the cold-stamped bearing is 2-4mm larger than that of the hot-forged bearing because the wall thickness of the outer ring of the cold-stamped bearing is thinner, about 1-2mm thinner. The extra 2-4mm can be allocated to the shaft head diameter of the cross shaft, making the shaft head diameter of the cross shaft significantly larger; the advantage of the length size of the cross shaft is similar; therefore, the strength of the universal joint cross shaft assembly is 30-50% higher than that of ordinary universal joints of the same specifications.

[0047] The long life is also mainly reflected in the use of cold-stamped bearings. According to the above analysis, when the outer diameters of the bearings are equal, the inner diameter of the outer ring of the cold-stamped bearing will be 2-4mm larger than that of the hot-forged bearing. In addition to being allocated to the shaft head diameter of the cross shaft, the extra 2-4mm can also be allocated to the needle roller diameter, which can significantly increase the diameter of the needle roller. At the same time, due to the increase in the length of the cross shaft, the stress state of the needle roller and the cross shaft is improved. The combination of these two factors makes the wear life of the universal joint cross shaft assembly 1-2 times higher than that of ordinary universal joints of the same specifications.

[0048] In addition, it should be noted that the shapes and names of the parts and components of the specific embodiments described in this specification may be different, and the above content described in this specification is only an example of the structure of the present invention. Any equivalent changes or simple changes made based on the structure, features and principles described in the patent concept of the present invention are included in the protection scope of the patent of the present invention. Those skilled in the art of the technology to which the present invention belongs can make various modifications or additions to the specific embodiments described or replace them in a similar manner. As long as they do not deviate from the structure of the present invention or exceed the scope defined by the claims, they should all fall within the protection scope of the present invention.

Claims

1. A double universal joint transmission shaft with an oil injection structure, comprising a short shaft fork (1), a double fork (2) and a long shaft fork (3), wherein both ends of the double fork (2) are respectively connected to the short shaft fork (1) and the long shaft fork (3) via a universal joint assembly, wherein the universal joint assembly comprises a cross shaft (4), a bearing (5) and a retaining spring (6), wherein the bearing (5) is mounted on the cross shaft (4), and the closed end of the bearing (5) is clamped to the short shaft fork (1), the double fork (2) and the long shaft fork (3) via the retaining spring (6), characterized in that: It also comprises an oil injection nozzle (7), the oil injection nozzle (7) being mounted on the double fork (2), the double fork (2) being provided with an oil injection channel (22) and an oil injection annular groove (23), the oil injection nozzle (7) being in communication with the oil injection channel (22), the oil injection channel (22) being in communication with the oil injection annular groove (23), and the oil injection annular groove (23) being in communication with the interior of the bearing (5); The cross shaft (4) comprises a shaft seat (41), a shaft head (42) and an oil injection channel (43); four shaft heads (42) are arranged on the shaft seat (41); the four shaft heads (42) are arranged in a cross-shaped structure; an oil injection channel (43) is arranged inside each of the four shaft heads (42); the oil injection channels (43) are interconnected; and the bearing (5) is sleeved on the shaft head (42); The bearing (5) comprises an outer ring (51), a needle roller (52) and an oil injection through hole (53); the outer ring (51) is sleeved on the shaft head (42); the needle roller (52) is arranged between the inner wall of the outer ring (51) and the outer wall of the shaft head (42); the oil injection through hole (53) is arranged on the side wall of the outer ring (51); and the oil injection ring groove (23) is connected to the oil injection through hole (53).

2. The double universal joint transmission shaft with oil injection structure according to claim 1, characterized in that: An oil seal (8) is sleeved on the cross shaft (4), and the oil seal (8) is arranged at the open end of the bearing (5).

3. The double universal joint transmission shaft with oil injection structure according to claim 1, characterized in that: The stub fork (1) is provided with a stub fork retaining groove (11), and the retaining spring (6) is located in the stub fork retaining groove (11).

4. The double universal joint transmission shaft with oil injection structure according to claim 1, characterized in that: The double fork (2) is provided with a double fork clamping slot (21), and the clamping spring (6) is located in the double fork clamping slot (21).

5. The double universal joint transmission shaft with oil injection structure according to claim 1, characterized in that: The long-axis fork (3) is provided with a long-axis fork clamping groove (31), and the clamping spring (6) is located in the long-axis fork clamping groove (31).

6. The double universal joint transmission shaft with oil injection structure according to claim 1, characterized in that: A central boss (61) and two side bosses (62) are arranged on the inner side of the clamping spring (6), and the two side bosses (62) are symmetrically arranged with respect to the central boss (61).

7. The double universal joint transmission shaft with oil injection structure according to claim 1, characterized in that: The double fork (2) is provided with an assembly countersunk hole (24).

8. The double universal joint transmission shaft with oil injection structure according to claim 1, characterized in that: The double fork (2) is provided with a mounting groove for mounting an oiling nozzle (7), and the oiling nozzle (7) is located in the mounting groove.

Images