A cross shaft assembly refueling structure and refueling method

Abstract

The present invention discloses a cross shaft assembly oiling structure and oiling method, belonging to the technical field of coupling equipment. It comprises: a cross shaft body, which has a shaft head; the shaft head comprises an oil filling shaft head, the end face of the oil filling shaft head is provided with a first oil filling nozzle, a second oil filling nozzle, a third oil filling nozzle and a fourth oil filling nozzle which are independently connected to an external oil supply device, the first oil filling nozzle, the second oil filling nozzle, the third oil filling nozzle and the fourth oil filling nozzle are respectively connected to and connected to the first bearing, the second bearing, the third bearing and the fourth bearing, and the first oil filling nozzle, the second oil filling nozzle, the third oil filling nozzle and the fourth oil filling nozzle are respectively and independently supplied with oil to the first bearing, the second bearing, the third bearing and the fourth bearing. The first oil filling nozzle, the second oil filling nozzle, the third oil filling nozzle and the fourth oil filling nozzle are provided on the end face of the oil filling shaft head, which are independently connected to the external oil supply device, so that the oil filling position is concentrated, ensuring that the four bearings can be oiled, thereby fully lubricating the bearings and reducing bearing failure.

Description

Technical Field

[0001] The present invention belongs to the technical field of coupling equipment, and more specifically, relates to a cross shaft assembly oiling structure and oiling method. Background Art

[0002] Cross-shaft universal joints are essential transmission equipment widely used in the steel rolling industry. Their joint bearings are subject to immense load-bearing and impact loads, while the roll end joints are also subject to severe corrosion from water vapor and gases. Therefore, they place extremely high demands on the lubrication of these bearings. Existing products have numerous and scattered refueling points, requiring regular, on-site manual refueling. However, limited refueling time prevents full and complete lubrication, resulting in some bearings not being fully lubricated. This, coupled with severe on-site water vapor corrosion, directly impacts the joint's service life.

[0003] The existing cross-shaft universal joint oiling method usually sets an oil cup hole in the middle of the cross shaft or in the 45° side direction of the angle between the two journals or at the bottom of the sleeve. A "cross" through-hole oil channel is set in the cross shaft to connect the four bearings. The oil cup adopts an ordinary straight-through pressure-injected oil cup or a joint-type pressure-injected oil cup. The oil gun fills grease into the universal joint from the oil cup. The grease first enters the "cross" through-hole oil channel and then squeezes into the four bearings to achieve lubrication. For example, Chinese patent application CN201220096811.2 discloses a cross shaft with an oil filling nozzle that can instantly supply oil to the four shaft heads; Chinese patent application CN201920885916.8 discloses a cross shaft universal joint assembly that can automatically add lubricating oil, an annular groove is opened at the connection between the shaft head and the cross shaft body, and the annular groove is provided in four groups. An oil storage tank is provided inside the cross shaft body, and an oil storage tank is provided inside the cross shaft body; Chinese patent application CN202120970679.2 discloses a A cross-axis universal joint assembly for adding lubricating oil includes a universal joint body, a plurality of shaft heads are provided on the side wall of the universal joint body, shaft sleeves are movably provided on the outer wall of the shaft head, and oil nozzles are provided on the top and bottom of the universal joint body; Chinese patent application CN201410709493.6 discloses an independently oiled universal shaft cross unit package structure, including a cross shaft, bearings, a cross shaft center hole and a cross-intersecting grease channel communicating with the cross shaft and the bearings are provided with a seal, the bearings are provided with independent oil filling holes, and independent grease nozzles are provided at the oil filling holes; Chinese patent application CN201610425593.5 discloses a cross-axis universal joint, including: a cross shaft, an oil inlet pipe connected to the interior of the cross shaft, and an oil nozzle connected to the oil inlet pipe; the cross shaft body is provided with a first oil nozzle hole and four second oil nozzle holes evenly distributed around the first oil nozzle hole; the end face of the shaft head is provided with a third oil nozzle hole; each oil nozzle hole is connected to a flexible oil inlet pipe and an oil nozzle.

[0004] However, in reality, due to factors such as manufacturing tolerances and foreign matter blockage, the four bearings require different pressures to release oil. The bearing requiring the lowest pressure can be filled and squeezed out of grease first, and the pressure in the oil channel will not increase significantly thereafter. The bearing requiring the highest pressure often cannot squeeze out grease. The failure to update the grease is equivalent to the failure to effectively maintain the bearing, which will eventually cause the bearing to fail prematurely. Summary of the Invention

[0005] 1. Problem to be solved

[0006] In view of the problem in the prior art that different oil pressures required for the four bearings cause poor bearing lubrication and thus failure, the present invention provides a cross-shaft assembly oiling structure with a centralized oiling position to fully lubricate the bearings and reduce bearing failure.

[0007] Another object of the present invention is to provide a method for refueling a cross shaft assembly to ensure that there is no oil leakage problem.

[0008] 2. Technical Solution

[0009] In order to solve the above problems, the technical solutions adopted by the present invention are as follows:

[0010] The cross shaft assembly refueling structure of the present invention comprises: a cross shaft body having a shaft head;

[0011] and a first bearing, a second bearing, a third bearing and a fourth bearing sleeved on the shaft head of the cross shaft body;

[0012] The shaft head includes an oil-filled shaft head, the end surface of which is provided with a first oil-filled nozzle, a second oil-filled nozzle, a third oil-filled nozzle and a fourth oil-filled nozzle which are independently connected to an external oil supply device. The first oil-filled nozzle, the second oil-filled nozzle, the third oil-filled nozzle and the fourth oil-filled nozzle are respectively connected to the oil supply chambers connected to the first bearing, the second bearing, the third bearing and the fourth bearing, and the first oil-filled nozzle, the second oil-filled nozzle, the third oil-filled nozzle and the fourth oil-filled nozzle are respectively and independently connected to the first bearing, the second bearing, the third bearing and the fourth bearing.

[0013] In a possible implementation manner of the present invention, the first oiling nozzle, the second oiling nozzle, the third oiling nozzle and the fourth oiling nozzle are evenly distributed around the center of the end surface of the oiling shaft head.

[0014] In a possible embodiment of the present invention, the first oiling nozzle, the second oiling nozzle, the third oiling nozzle and the fourth oiling nozzle are respectively connected to the oil supply chambers of the first bearing, the second bearing, the third bearing and the fourth bearing through oil supply pipelines.

[0015] In one possible embodiment of the present invention, a through hole is opened along the axis of the shaft head; a pipeline setting cavity is opened on the oil filling shaft head, each oil supply pipeline supplies oil to the bearing through an oil supply distributor, and the oil supply distributor is sealed with the through hole through a sealing ring.

[0016] In a possible implementation manner of the present invention, the oil supply pipeline includes but is not limited to a stainless steel pipe, a rubber hose and a metal copper pipe.

[0017] The oil supply distance between the first oil nozzle and the first bearing is L1, the oil supply distance between the second oil nozzle and the second bearing is L2, the oil supply distance between the third oil nozzle and the third bearing is L3, and the oil supply distance between the fourth oil nozzle and the fourth bearing is L4. The minimum oil supply pressures provided by the external oil supply device for the first oil nozzle, the second oil nozzle, the third oil nozzle, and the fourth oil nozzle are P1, P2, P3, and P4, respectively. The minimum diameters of the oil supply pipelines are D1 (corresponding to the first oil nozzle), D2 (corresponding to the second oil nozzle), D3 (corresponding to the third oil nozzle), and D4 (corresponding to the fourth oil nozzle), respectively, satisfying the following relationship expression:

[0018] 1) P1=0.9P2=0.9P4=0.95P3; L1=0.1L2=0.1L4=0.12L3;

[0019] 2) D1=D2=D3=D4.

[0020] In one possible implementation of the present invention, when the first, second, third and fourth oiling nozzles are evenly distributed, resonance may occur during the oil supply process, causing the four oiling nozzles to fall off from the external oil supply equipment. Therefore, in order to solve this problem, the first, second, third and fourth oiling nozzles adopt a cross distribution pattern (the major axis and minor axis structure of an ellipse), that is, the first and third oiling nozzles are distributed on the major axis, and the second and fourth oiling nozzles are distributed on the minor axis. Through a large number of field uses, it has been found that the problem of falling off caused by resonance can be effectively reduced.

[0021] Furthermore, the length of the major axis is H, the length of the minor axis is h, and the length of the major axis H=(3-5)h.

[0022] In one possible implementation of the present invention, the external oil supply equipment includes but is not limited to a hydraulic pump, an electric pump, and a pneumatic pump.

[0023] In one possible embodiment of the present invention, the first oiling nozzle, the second oiling nozzle, the third oiling nozzle and the fourth oiling nozzle all adopt the oiling nozzles of the existing technology, such as the oiling nozzle disclosed in Chinese patent application CN215807806U, which includes a central shaft and an oiling nozzle arranged on the surface of the central shaft, the oiling nozzle is a hollow cylindrical structure, the oiling nozzle includes an oil inlet and an oil outlet arranged on the central shaft, an oil sealing body for blocking the oil inlet and a spring provided on the lower surface of the oil sealing body and connected to the upper surface of the central shaft is provided inside the oiling nozzle, a plurality of sliding grooves are provided in the axial direction of the inner wall of the oiling nozzle, a slider adapted to the sliding groove is provided on the lower surface of the oil sealing body along the radial direction of the oiling nozzle, and an oil scraper ring with an annular structure is provided on the upper surface of the slider for scraping contaminants off the inner wall of the oiling nozzle.

[0024] The present invention also provides a cross shaft assembly refueling method, comprising the following steps: when the minimum oil supply pressures P1, P2, P3 and P4 satisfy the following relationship, turning on the external oil supply device to supply oil to the first oil nozzle, the second oil nozzle, the third oil nozzle and the fourth oil nozzle respectively, and the relationship is: P1=0.9P2=0.9P4=0.95P3.

[0025] 3. Beneficial effects

[0026] Compared with the prior art, the present invention has the following beneficial effects:

[0027] The cross-shaft assembly oiling structure of the present invention is provided with a first oiling nozzle, a second oiling nozzle, a third oiling nozzle and a fourth oiling nozzle which are independently connected to an external oil supply device on the end face of the oiling shaft head, so that the oiling positions are centralized, which is more convenient especially for factories with limited space, and ensures that all four bearings can be oiled, thereby fully lubricating the bearings and reducing bearing failure. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] The technical solutions of the present invention will be further described in detail below with reference to the accompanying drawings and embodiments. However, it should be understood that these drawings are designed for illustrative purposes only and are not intended to limit the scope of the present invention. Furthermore, unless otherwise specified, these drawings are intended only to conceptually illustrate the structures described herein and are not necessarily drawn to scale.

[0029] Figure 1 This is a schematic structural diagram of the cross shaft assembly refueling structure of the present invention;

[0030] Figure 2 for Figure 1 Side view of

[0031] Figure 3 for Figure 2 Sectional view along line AA;

[0032] Figure 4This is a vibration detection numerical diagram of a cross shaft assembly refueling structure of the present invention;

[0033] Figure 5 Another side view of the cross shaft assembly refueling structure of the present invention;

[0034] Figure 6 for Figure 4 A partial enlarged view of

[0035] Figure 7 This is a numerical diagram of vibration detection of another cross shaft assembly refueling structure of the present invention.

[0036] Description of reference numerals:

[0037] 10. Cross shaft body; 11. Oiling shaft head; 111. Pipeline setting cavity; 112. Through-hole; 113. Sealing ring; 114. Oil supply pipeline; 12. First bearing; 13. Second bearing; 14. Third bearing; 15. Fourth bearing; 21. First oiling nozzle; 22. Second oiling nozzle; 23. Third oiling nozzle; 24. Fourth oiling nozzle; 25. Oil supply distributor. DETAILED DESCRIPTION

[0038] The following detailed description of exemplary embodiments of the present invention refers to the accompanying drawings, which form a part of the description, and in which exemplary embodiments of the present invention that can be implemented are shown as examples. Although these exemplary embodiments are described in sufficient detail to enable those skilled in the art to implement the present invention, it should be understood that other embodiments can be implemented and various changes can be made to the present invention without departing from the spirit and scope of the present invention. The following more detailed description of the embodiments of the present invention is not intended to limit the scope of the claimed invention, but is merely for illustration and does not limit the description of the features and characteristics of the present invention, so as to propose the best way to perform the present invention and be sufficient to enable those skilled in the art to implement the present invention. Therefore, the scope of the present invention is limited only by the appended claims.

[0039] The following detailed description of the present invention and example embodiments may be better understood with reference to the accompanying drawings, in which elements and features of the present invention are identified by reference numerals.

[0040] Example 1

[0041] like Figures 1 to 3 As shown, the cross shaft assembly refueling structure of this embodiment includes: a cross shaft body 10, which has a shaft head; the material of the cross shaft body 10 is alloy structural steel, and its mechanical properties are: a) δ m ≥1150MPa; b)δ cL ≥900MPa; c)A KU≥60J; the journal surface of the cross shaft body 10 should be carburized, the effective carburized layer depth is 1.3mm~1.8mm, and the surface hardness is 58HRC~62HRC; the journal size tolerance zone should comply with the h6 level requirements in GB / T1800.4.

[0042] And the first bearing 12, the second bearing 13, the third bearing 14 and the fourth bearing 15 are sleeved on the shaft head of the above-mentioned cross shaft body 10, wherein the structures of the first bearing 12, the second bearing 13, the third bearing 14 and the fourth bearing 15 are consistent: the matching structure of the first bearing 12, the second bearing 13, the third bearing 14 and the fourth bearing 15 and the shaft head is as disclosed in Chinese patent application CN202211375678.9:

[0043] 1. Bearing outer ring

[0044] 1) The material of the bearing outer ring is alloy structural steel, and its mechanical properties are: a) δ m ≥1150MPa; b)δ cL ≥900MPa; c)A KU ≥60J.

[0045] 2) Carburizing treatment of internal and external working surfaces, effective carburizing layer depth is 1.3mm~1.8mm, surface hardness is 58HRC~62HRC;

[0046] 3) The dimensional tolerance zone of the outer working surface of the bearing outer ring shall comply with the h6 grade requirements in GB / T1800.4;

[0047] 4) The inner working surface dimension tolerance of the bearing outer ring shall comply with the requirements of level 6 in GB / T1800.4;

[0048] 5) The cylindricity tolerance of the inner and outer working surfaces of the bearing outer ring should not be greater than Grade 6 in GB / T1184, and the coaxiality should not be greater than Grade 6 in GB / T1184;

[0049] 6) The inner and outer surface roughness R of the bearing outer ring shall not exceed 0.4μm and 0.8μm respectively;

[0050] 7) After the outer ring of the bearing is processed, it should be subjected to ultrasonic testing, and the quality grade should comply with the requirements of Class I in JB / T5000.15.

[0051] 2. Bearing rollers

[0052] 1) The manufacturing of bearing rollers shall comply with Grade II of GB / T4661.

[0053] 2) Bearing assembly

[0054] A. After assembly, the total circumferential clearance of the bearing rollers should generally be between 0.45mm and 0.70mm;

[0055] B. After assembly, the total axial clearance of the bearing rollers should generally be between 0.25mm and 0.40mm.

[0056] Combine Figure 1 and Figure 2 The above-mentioned shaft head includes an oil-filled shaft head 11, and the end face of the oil-filled shaft head 11 is provided with a first oil-filling nozzle 21, a second oil-filling nozzle 22, a third oil-filling nozzle 23 and a fourth oil-filling nozzle 24 which are independently connected to an external oil supply device. The above-mentioned external oil supply device includes but is not limited to a hydraulic pump, an electric pump and a pneumatic pump, preferably an electric pump.

[0057] In this embodiment, the above-mentioned first oiling nozzle 21, second oiling nozzle 22, third oiling nozzle 23 and fourth oiling nozzle 24 all adopt oiling nozzles of existing technology, such as the oiling nozzle disclosed in Chinese patent application CN215807806U, which includes a central shaft and an oiling nozzle arranged on the surface of the central shaft. The oiling nozzle is a hollow cylindrical structure. The oiling nozzle includes an oil inlet and an oil outlet arranged on the central shaft. An oil sealing body for blocking the oil inlet and a spring provided on the lower surface of the oil sealing body and connected to the upper surface of the central shaft are provided inside the oiling nozzle. A plurality of sliding grooves are provided in the axial direction of the inner wall of the oiling nozzle. A sliding block adapted to the sliding groove is provided on the lower surface of the oil sealing body along the radial direction of the oiling nozzle. The upper surface of the sliding block is provided with an oil scraper ring with an annular structure for scraping contaminants off the inner wall of the oiling nozzle.

[0058] Under the action of the external oil supply equipment, the first oil nozzle 21, the second oil nozzle 22, the third oil nozzle 23 and the fourth oil nozzle 24 are respectively connected to the oil supply chambers (not marked in the figure) of the first bearing 12, the second bearing 13, the third bearing 14 and the fourth bearing 15, and the first oil nozzle 21, the second oil nozzle 22, the third oil nozzle 23 and the fourth oil nozzle 24 independently supply oil to the first bearing 12, the second bearing 13, the third bearing 14 and the fourth bearing 15.

[0059] As a possible structure in this embodiment, combined with Figure 2 As shown, the first oiling nozzle 21, the second oiling nozzle 22, the third oiling nozzle 23, and the fourth oiling nozzle 24 are evenly distributed around the center of the end surface of the oiling shaft head 11. The first oiling nozzle 21, the second oiling nozzle 22, the third oiling nozzle 23, and the fourth oiling nozzle 24 are respectively connected to the oil supply chambers of the first bearing 12, the second bearing 13, the third bearing 14, and the fourth bearing 15 through the oil supply pipeline 114. The oil supply pipeline 114 includes but is not limited to a stainless steel pipe, a rubber hose, and a metal copper pipe.

[0060] In this embodiment, a through hole 112 is opened along the axis of the shaft head. This design structure is completed when the cross shaft body 10 is processed. The diameter of the through hole 112 is larger than the diameter of the oil supply line 114; a pipeline setting cavity 111 is opened on the above-mentioned oil filling shaft head 11, and each oil supply line 114 passes through the pipeline setting cavity 111 and the through hole 112, and then supplies oil to the bearing through the oil supply distributor 25. The oil supply distributor 25 is sealed with the through hole 112 by an O-ring 113, wherein the oil supply distributor 25 and the O-ring 113 are both commercially available products.

[0061] Taking into account that each part of the first bearing 12, the second bearing 13, the third bearing 14 and the fourth bearing 15 requires oil supply, an oil supply distributor 25 is set at the end of each oil supply pipeline, and the lubricating grease is directly transported to the oil supply distributor 25 by the oil supply pipeline 114. On the one hand, it can reduce oil leakage, and on the other hand, it can reduce the corrosion of the grease to the inside of the cross shaft body 10 corresponding to the through hole 114, which can effectively avoid the problem of failure.

[0062] The oil supply distance between the first oil nozzle 21 and the first bearing 12 is L1, the oil supply distance between the second oil nozzle 22 and the second bearing 13 is L2, the oil supply distance between the third oil nozzle 23 and the third bearing 14 is L3, and the oil supply distance between the fourth oil nozzle 24 and the fourth bearing 15 is L4. The minimum oil supply pressures provided by the external oil supply device to the first oil nozzle 21, the second oil nozzle 22, the third oil nozzle 23, and the fourth oil nozzle 24 are P1, P2, P3, and P4, respectively. The minimum diameters of the oil supply pipeline 114 are D1 (corresponding to the first oil nozzle 21), D2 (corresponding to the second oil nozzle 22), D3 (corresponding to the third oil nozzle 23), and D4 (corresponding to the fourth oil nozzle 24), respectively, satisfying the following relationship expression:

[0063] 1) P1=0.9P2=0.9P4=0.95P3; L1=0.1L2=0.1L4=0.12L3;

[0064] 2) D1=D2=D3=D4.

[0065] Combine Figure 1 As shown, the oil supply distances of the second bearing 13, the third bearing 14 and the fourth bearing 15 are different, and there are turns in the oil supply pipelines of the second bearing 13 and the fourth bearing 15, so the oil supply pressure is relatively high.

[0066] When the first oil injection nozzle 21, the second oil injection nozzle 22, the third oil injection nozzle 23 and the fourth oil injection nozzle 24 are evenly distributed, during the simultaneous oil supply process of the four oil nozzles, due to the uninterrupted oil delivery of the oil pump, the cross-section suddenly moves and narrows at the oil nozzle, resulting in intermittent vibration of the oil supply in the pipeline. The four oil nozzles on the same plane will produce intermittent resonance problems, causing some of the four oil nozzles to fall off from the external oil supply equipment, causing the oil to be exposed from the gap and pollute the environment. To address this phenomenon, when the four oil nozzles are supplying oil at the same time, a vibration instrument (such as the Hongda Tianju vibration detection instrument LD-TL) is used to detect the vibration value. The normal vibration displacement value is 6μm, and the maximum resonant vibration displacement value reaches 16μm. Figure 4 As shown, this vibration mutation is the main cause of shedding.

[0067] Therefore, to understand this problem, Figure 4 As shown, the first, second, third, and fourth oiling nozzles 21, 22, 23, and 24 are arranged in a cross-shaped pattern (the major and minor axes of an ellipse), with the first and third oiling nozzles 21, 23 positioned on the major axis, and the second and fourth oiling nozzles 22, 24 positioned on the minor axis. This pattern has been shown to effectively reduce the risk of detachment caused by resonance through extensive field use. When the four nozzles are simultaneously supplying oil, vibration measurements are taken using a vibration instrument (e.g., the Hongda Tianju Vibration Detector LD-TL). The resulting average vibration displacement is 4 μm. Figure 7 As shown, it can be determined at this moment that the vibration waves generated by the two oiling nozzles on the short shaft come into contact first, and the vibration waves generated by the two oiling nozzles on the long shaft are transmitted to the contact point. This design can effectively offset part of the resonance effect.

[0068] Further, in Figure 5 and Figure 6 The length of the major axis is H, the length of the minor axis is h, and the length of the major axis H = (3-5) h. The preferred oil supply line 114 is a stainless steel tube. Through extensive use, the inventors surprisingly discovered that stainless steel tubes have a better anti-resonance effect than rubber tubes.

[0069] This embodiment also provides a cross shaft assembly refueling method, comprising the following steps: when the minimum oil supply pressures P1, P2, P3 and P4 satisfy the following relationship, turn on the external oil supply device to supply oil to the first oil nozzle 21, the second oil nozzle 22, the third oil nozzle 23 and the fourth oil nozzle 24 respectively, and the relationship is: P1=0.9P2=0.9P4=0.95P3.

[0070] The structural design of this embodiment not only solves the problems involved in the background technology, but also eliminates the resonance shedding problem caused by oil supply, and has a strong application prospect.

Claims

1. A cross shaft assembly refueling structure, comprising: The cross shaft body (10) has a shaft head and is characterized in that and a first bearing (12), a second bearing (13), a third bearing (14), and a fourth bearing (15) sleeved on the shaft head; The shaft head comprises an oil-filled shaft head (11), the end surface of which is provided with a first oil-filled nozzle (21), a second oil-filled nozzle (22), a third oil-filled nozzle (23) and a fourth oil-filled nozzle (24) which are independently connected to an external oil supply device, the first oil-filled nozzle (21), the second oil-filled nozzle (22), the third oil-filled nozzle (23) and the fourth oil-filled nozzle (24) being respectively connected to the oil supply chambers of the first bearing (12), the second bearing (13), the third bearing (14) and the fourth bearing (15), and the first oil-filled nozzle (21), the second oil-filled nozzle (22), the third oil-filled nozzle (23) and the fourth oil-filled nozzle (24) respectively and independently supplying oil to the first bearing (12), the second bearing (13), the third bearing (14) and the fourth bearing (15); The first oiling nozzle (21), the second oiling nozzle (22), the third oiling nozzle (23) and the fourth oiling nozzle (24) are evenly distributed around the center of the end surface of the oiling shaft head (11); The first oiling nozzle (21), the second oiling nozzle (22), the third oiling nozzle (23) and the fourth oiling nozzle (24) are respectively connected to the first bearing (12), the second bearing (13), the third bearing (14) and the fourth bearing (15) via the oil supply pipeline (114); The oil supply distance between the first oiling nozzle (21) and the first bearing (12) is L1, the oil supply distance between the second oiling nozzle (22) and the second bearing (13) is L2, the oil supply distance between the third oiling nozzle (23) and the third bearing (14) is L3, and the oil supply distance between the fourth oiling nozzle (24) and the fourth bearing (15) is L4. The minimum oil supply pressures provided by the external oil supply device to the first oiling nozzle (21), the second oiling nozzle (22), the third oiling nozzle (23) and the fourth oiling nozzle (24) are P1, P2, P3 and P4 respectively. The minimum diameters of the oil supply pipeline (114) are D1, D2, D3 and D4 respectively, satisfying the following relationship expression: 1) P1=0.9P2=0.9P4=0.95P3; L1=0.1L2=0.1L4=0.12L3; 2) D1=D2=D3=D4.

2. The cross shaft assembly refueling structure according to claim 1, characterized in that: A through hole (112) is provided along the axis of the shaft head; a pipeline setting cavity (111) is provided on the oil injection shaft head (11); each oil supply pipeline (114) supplies oil to the bearing through an oil supply distributor (25); and the oil supply distributor (25) is sealed with the through hole (112) through a sealing ring (113).

3. The cross shaft assembly refueling structure according to claim 2, characterized in that: The oil supply pipeline (114) comprises a stainless steel pipe, a rubber hose and a metal copper pipe.

4. The cross shaft assembly refueling structure according to claim 3, characterized in that: The first oiling nozzle (21), the second oiling nozzle (22), the third oiling nozzle (23) and the fourth oiling nozzle (24) adopt a distribution pattern of an elliptical major axis and minor axis structure.

5. The cross shaft assembly refueling structure according to claim 4, characterized in that: The length of the major axis is H, the length of the minor axis is h, and the length of the major axis H = (3-5)h.

6. The cross shaft assembly refueling structure according to claim 5, characterized in that: The external oil supply equipment includes a hydraulic pump and a pneumatic pump.

7. A refueling method for a cross shaft assembly refueling structure according to any one of claims 1 to 6, characterized in that: The following steps are involved: When the minimum oil supply pressures P1, P2, P3 and P4 satisfy the following relationship, the external oil supply device is turned on to supply oil to the first oil injection nozzle (21), the second oil injection nozzle (22), the third oil injection nozzle (23) and the fourth oil injection nozzle (24), respectively. The relationship is: P1=0.9P2=0.9P4=0.95P3.

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