An assembly structure of a skeleton oil seal of a driving shaft of a main pump of an oil leakage-proof hydraulic system

Abstract

The utility model provides a kind of leakage-proof oil hydraulic system main pump drive shaft skeleton oil seal assembly structure, including main pump drive shaft, with the supporting seat of pump body shell assembly, with the fixed sealing end cover of support seat outer end surface, skeleton oil seal is set on the drive shaft, bearing is set on drive shaft and located between skeleton oil seal and supporting seat, its rubber body is provided with protruding first sealing lip and second sealing lip on the assembly surface with drive shaft.The drive shaft skeleton oil seal assembly structure of this embodiment, by controlling the surface roughness of driving main shaft to improve shaft surface oil storage capacity and significantly reduce the wear of rubber body of skeleton oil seal on the surface of drive shaft, prolongs skeleton oil seal life;Skeleton oil seal is set using multiple sealing lip structure, forms multiple sealing defense lines in axial and radial, significantly improves overall sealing redundancy, effectively blocks axial and radial leakage path, to greatly improve sealing effect, especially suitable for large and medium-sized engineering machinery application.

Description

Technical Field

[0001] This utility model relates to the field of mechanical assembly technology, and in particular to an oil seal assembly structure for the main pump drive shaft skeleton of a high-pressure hydraulic system for engineering machinery to prevent oil leakage. Background Technology

[0002] Large and medium-sized construction machinery, such as cranes and excavators, generally use hydraulic systems to provide a large power output source to meet application requirements. The main pump is the core component and power unit of the hydraulic system. It is used to convert the mechanical energy output from the prime mover into the pressure energy and kinetic energy of the working fluid, providing a certain flow and pressure to the hydraulic system and driving actuators such as cylinders and motors to perform work. The working pressure of the main pump used in this type of construction machinery may be as high as about 40MPa. After long-term operation, oil leakage often occurs at the skeleton oil seal on the drive shaft of the main pump. This is mainly due to interface leakage of hydraulic oil at the sealing surface. If left untreated for a long time, the service life of internal components and seals will be significantly reduced, affecting the normal operation of the construction machinery.

[0003] Oil leakage at the hydraulic system main pump drive shaft skeleton oil seal is related to several factors. Since the drive shaft and the skeleton oil seal achieve sealing through an interference fit, the skeleton oil seal has strict requirements on the drive shaft's dimensional tolerances and surface roughness. Excessive drive shaft surface roughness causes the shaft's protrusions to penetrate the oil film and contact the lip. Shaft rotation then cuts the sealing lip, accelerating lip wear. Simultaneously, excessive drive shaft surface roughness increases the coefficient of friction between the drive shaft and the skeleton oil seal, generating more heat and exacerbating wear, ultimately leading to premature seal failure and leakage. Furthermore, the hardness of the skeleton oil seal and the design of the sealing lip also affect the sealing performance of the assembly structure. Utility Model Content

[0004] The purpose of this invention is to address the shortcomings of existing technologies by proposing a hydraulic system main pump drive shaft skeleton oil seal assembly structure to prevent oil leakage, thereby improving the sealing and protection effect of the assembly structure and extending the service life of internal components and skeleton oil seals.

[0005] To achieve the above objectives, the present invention adopts the following technical solution: A hydraulic system main pump drive shaft skeleton oil seal assembly structure for preventing oil leakage. The assembly structure includes a main pump drive shaft, a support base fixedly assembled with the pump body housing, a sealing end cover fixedly connected to the outer end face of the support base, and a skeleton oil seal sleeved on the drive shaft. The skeleton oil seal is disposed between the sealing end cover and the support base, and a bearing is disposed on the drive shaft and located between the skeleton oil seal and the support base. The skeleton oil seal includes a skeleton and a rubber body surrounding the skeleton. The rubber body has a first sealing lip and a second sealing lip protruding on its assembly surface with the drive shaft, and a third sealing lip on its assembly surface with the support base. The first sealing lip and the second sealing lip are arranged at an angle to the drive shaft in the direction facing the pump body.

[0006] Preferably, the angle between the first sealing lip and the second sealing lip and the drive shaft is 55-65 degrees.

[0007] In a further preferred embodiment, the rubber body of the skeleton oil seal is provided with a fourth sealing lip on the mating surface with the bearing, and the fourth sealing lip abuts against the outer ring end face of the bearing.

[0008] Preferably, the surface roughness Ra of the drive shaft at the assembly points with the skeleton oil seal and the bearing assembly points does not exceed 1.0.

[0009] Preferably, the surface roughness Ra of the drive shaft at the assembly points with the skeleton oil seal and the bearing assembly points does not exceed 0.8.

[0010] Preferably, the height of the first sealing lip and the second sealing lip protruding from the surface of the rubber body is between 0.7 and 1.2 mm.

[0011] More preferably, the rubber body of the skeleton oil seal is a ternary copolymer fluorinated rubber of tetrafluoroethylene, fluorinated vinyl ether and vinylidene fluoride, wherein the mass fraction of fluorine is controlled between 60% and 67%.

[0012] More preferably, the Shore hardness of the rubber body of the skeleton oil seal is 85-90.

[0013] The beneficial effects of this embodiment are that, in the hydraulic system main pump drive shaft skeleton oil seal assembly structure, the surface roughness of the drive shaft is controlled to improve the oil storage capacity of the shaft surface and significantly reduce the wear of the drive shaft surface on the rubber body of the skeleton oil seal, thus extending the life of the skeleton oil seal; the skeleton oil seal adopts a multi-seal lip structure to form multiple sealing defenses in the axial and radial directions, significantly improving the overall sealing redundancy, effectively blocking axial and radial leakage paths, thereby greatly improving the sealing effect, and is particularly suitable for application in large and medium-sized engineering machinery. Attached Figure Description

[0014] Figure 1This is a schematic diagram of the structure of a hydraulic system main pump drive shaft skeleton oil seal assembly structure for preventing oil leakage, according to an embodiment of the present invention.

[0015] Figure 2 for Figure 1 A schematic diagram of the cross-sectional structure of the skeleton oil seal used in the assembly structure.

[0016] In the figure, 10-drive shaft, 20-support seat, 30-sealing end cap, 40-skeleton oil seal, 41-skeleton, 42-rubber body, 421-first sealing lip, 422-second sealing lip, 423-third sealing lip. Detailed Implementation

[0017] To make the objectives, technical solutions, and advantages of this utility model clearer, the technical solutions of the embodiments of this utility model will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some, not all, of the embodiments of this utility model. Based on the described embodiments of this utility model, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this utility model. It is understood that, without conflict, some technical means of the various embodiments described herein can be substituted for or combined with each other.

[0018] In the description of this utility model, the terms "first," "second," etc., are used only to distinguish the described objects and have no sequential or technical meaning. Therefore, objects specified with "first," "second," etc., may explicitly or implicitly include one or more of those objects. Furthermore, the words "one" or "a" do not indicate a quantity limitation, but rather indicate the presence of at least one, while "multiple" indicates at least two.

[0019] Reference Figure 1 The diagram illustrates a hydraulic system main pump drive shaft skeleton oil seal assembly structure to prevent oil leakage. The assembly structure includes a main pump drive shaft 10 and a support 20 fixedly assembled with the pump housing (in this application, the pump housing is...). Figure 1 The right side of the assembly structure shown (not shown in the figure) is a sealing end cap 30 fixedly connected to the outer end face of the support 20. A skeleton oil seal 40 is sleeved on the drive shaft 10. The skeleton oil seal 40 is located between the sealing end cap 30 and the support 20. A bearing 50 is located on the drive shaft 10 and between the skeleton oil seal 40 and the support 20. (See also...) Figure 2The skeleton oil seal 40 includes a skeleton 41 and a rubber body 42 surrounding the skeleton 41. The rubber body 42 has a protruding first sealing lip 421 and a second sealing lip 422 on its mounting surface with the drive shaft 10, and a third sealing lip 423 on its mounting surface with the support seat 20. The first sealing lip 421 and the second sealing lip 422 are angled towards the drive shaft 10 in the direction facing the pump body. Since the main purpose of this application is to prevent internal oil leakage to the outside, the first and second sealing lips are angled towards the pump body. In a preferred embodiment, the angle is 55-65 degrees.

[0020] In a preferred embodiment, see Figure 1 and Figure 2 In the assembly structure of this embodiment, the rubber body 42 of the skeleton oil seal 40 is further provided with a fourth sealing lip 424 on the mating surface with the bearing 50, and the fourth sealing lip 424 abuts against the outer ring end face of the bearing 50. Thus, two layers of sealing structure are also provided in the radial direction of the assembly, improving the radial sealing performance of the assembly structure.

[0021] In the assembly structure of the main pump drive shaft skeleton oil seal in a hydraulic system, the surface roughness of the drive shaft affects its wear resistance, fit stability, fatigue strength, corrosion resistance, sealing performance, and contact stiffness. The flatter the microscopic profile surface, the fewer the sharp points, or the narrower the gaps, the better the surface can store oil, which is beneficial for extending the life of the skeleton oil seal. Therefore, in the assembly structure, especially at the skeleton oil seal assembly area and the bearing assembly area, it is necessary to strictly control the surface roughness of the drive shaft. In a preferred embodiment, the surface roughness Ra of the drive shaft 10 at the assembly area with the skeleton oil seal 40 and the bearing 50 does not exceed 1.0; more preferably, the surface roughness Ra does not exceed 0.8.

[0022] Oil seals typically prevent clearance changes caused by load variations, shape tolerances, and roughness through interference friction contact between a flexible sealing lip and the spindle. The material, oil resistance, and compatibility with hydraulic oil of the rubber body of the oil seal affect material aging and lip swelling. Furthermore, at high speeds, frictional heat from the sealing surface can disrupt the sealing ring's tracking ability, accelerating ring wear. Therefore, the rubber body of the oil seal needs to be made of materials with low friction coefficient, good thermal conductivity, and suitability for high-temperature applications to prevent aging and deformation. In a preferred embodiment of this application, the rubber body of the oil seal is a ternary copolymer fluororubber composed of tetrafluoroethylene, fluorinated vinyl ether, and vinylidene fluoride, with the fluorine content controlled between 60% and 67% by mass. Experiments have shown that this fluororubber exhibits high temperature resistance, oil resistance, oxidation resistance, chemical corrosion resistance, and excellent tear strength, ensuring the sealing performance of the oil seal under long-term use.

[0023] Since the skeleton oil seal generally achieves its sealing performance by using a flexible sealing lip to press against the spindle, if the pressing amount of the sealing lip is too large or too small, it will affect the sealing performance and service life. According to the test results, in this embodiment, the height of the first sealing lip 421 and the second sealing lip 422 protruding from the surface of the rubber body is between 0.7-1.2 mm.

[0024] In addition, a higher hardness of the rubber body of the skeleton oil seal can significantly improve its ability to resist extrusion under high pressure, that is, it has strong resistance to deformation and tearing. Therefore, the Shore hardness of the rubber body of the skeleton oil seal in this embodiment is 85 to 90.

[0025] In the hydraulic system main pump drive shaft skeleton oil seal assembly structure of this embodiment, the surface roughness of the drive shaft is controlled to improve the oil storage capacity of the shaft surface and significantly reduce the wear of the drive shaft surface on the rubber body of the skeleton oil seal, thus extending the life of the skeleton oil seal. A double sealing lip is provided on the assembly surface of the skeleton oil seal and the drive shaft, which not only enhances the sealing effect of the sealing ring but also compensates for the wear of the sealing lip. This not only prevents internal oil leakage but also effectively prevents dust, moisture, and other contaminants from intruding and damaging the sealing lip. Sealing lips are also provided on the mating surfaces of the skeleton oil seal with the support seat and bearings. By controlling the material and hardness of the rubber body of the skeleton oil seal, the sealing and leak-proof function of the skeleton oil seal in the assembly structure is further improved.

[0026] This utility model discloses a hydraulic system main pump drive shaft skeleton oil seal assembly structure. The skeleton oil seal adopts a multiple sealing lip structure, forming multiple sealing defenses in the axial and radial directions, significantly improving the overall sealing redundancy, effectively blocking axial and radial leakage paths, thereby greatly improving the sealing effect. It is particularly suitable for application in large and medium-sized engineering machinery.

[0027] This utility model has been described by the above-described embodiments; however, these embodiments are merely examples for implementing this utility model. It must be noted that the disclosed embodiments do not limit the scope of this utility model. Conversely, any modifications and refinements made without departing from the spirit and scope of this utility model are within the scope of patent protection of this utility model.

Claims

1. A leak-proof hydraulic system main pump drive shaft skeleton oil seal assembly structure, characterized in that, The assembly structure includes a main pump drive shaft, a support base fixedly assembled with the pump body housing, a sealing end cover fixedly connected to the outer end face of the support base, and a skeleton oil seal sleeved on the drive shaft. The skeleton oil seal is located between the sealing end cover and the support base, and a bearing is located on the drive shaft and between the skeleton oil seal and the support base. The skeleton oil seal includes a skeleton and a rubber body surrounding the skeleton. The rubber body has a first sealing lip and a second sealing lip protruding on its assembly surface with the drive shaft, and a third sealing lip on its assembly surface with the support base. The first sealing lip and the second sealing lip are set at an angle to the drive shaft in the direction facing the pump body.

2. The oil seal assembly structure for the main pump drive shaft skeleton of an oil-leakage-proof hydraulic system as described in claim 1, characterized in that, The angle between the first and second sealing lips and the drive shaft is 55-65 degrees.

3. The oil seal assembly structure for the main pump drive shaft skeleton of an oil-leakage-proof hydraulic system as described in claim 1 or 2, characterized in that, The rubber body of the skeleton oil seal is provided with a fourth sealing lip on the mating surface with the bearing, and the fourth sealing lip abuts against the outer ring end face of the bearing.

4. The oil seal assembly structure for the main pump drive shaft skeleton of an oil-leakage-proof hydraulic system as described in claim 3, characterized in that, The surface roughness Ra of the drive shaft assembly part with the skeleton oil seal and the bearing assembly part does not exceed 1.

0.

5. The oil seal assembly structure for the main pump drive shaft skeleton of an oil-leakage-proof hydraulic system as described in claim 4, characterized in that, The surface roughness Ra of the drive shaft assembly part with the skeleton oil seal and the bearing assembly part does not exceed 0.

8.

6. The oil seal assembly structure for the main pump drive shaft skeleton of an oil-leakage-proof hydraulic system as described in claim 4, characterized in that, The height of the first and second sealing lips protruding from the surface of the rubber body is between 0.7 and 1.2 mm.

7. The oil seal assembly structure for the main pump drive shaft skeleton of an oil-leakage-proof hydraulic system as described in claim 3, characterized in that, The Shore hardness of the rubber body of the aforementioned skeleton oil seal is 85-90.

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