A reciprocating skeleton oil seal and a low-friction shock absorber using the same

Abstract

The application relates to the technical field of shock absorbers, and discloses a reciprocating skeleton oil seal and a low-friction shock absorber adopting the oil seal, which comprises a super-elastic sealing body, a main metal skeleton and a secondary metal skeleton; the main metal skeleton is fixed outside the super-elastic sealing body and located at a fixed position of a guide; and the secondary metal skeleton is fixed outside the super-elastic sealing body and located at a position of sealing hydraulic oil. Compared with the prior art, the shock absorber is designed and optimized to be the reciprocating skeleton oil seal, so that the friction between the oil seal of the shock absorber and the piston rod of the shock absorber can be further reduced while the sealing property is ensured, the service life of the shock absorber is prolonged, and the comfort performance of the shock absorber is improved.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of shock absorber, in particular to a reciprocating skeleton oil seal and a low-friction shock absorber using the same. BACKGROUND

[0002] The shock absorber is used to suppress the oscillation of the spring when absorbing the vibration and rebounding, and to suppress the impact from the road. It is widely used in automobiles to accelerate the damping of the frame and the body vibration, so as to improve the riding comfort of the automobile. The reciprocating skeleton oil seal plays an important sealing role when moving up and down on the shock absorber. On the one hand, it prevents the leakage of the shock absorber oil, and on the other hand, it prevents the entry of external foreign matters into the shock absorber.

[0003] The sealing performance and the friction performance of the shock absorber oil seal play a crucial role in the service life and the comfort performance of the shock absorber. The size of the friction between the oil seal lip and the piston rod and the contact pressure play an important role. The greater the friction, the faster the wear of the oil seal, and the worse the sealing performance. At the same time, if the contact pressure is too small, the sealing ability will be poor. Therefore, how to ensure a larger contact pressure and a smaller friction to improve the sealing effect has become a key technology for the research and development of the shock absorber oil seal. SUMMARY

[0004] In view of the deficiencies of the prior art, the present application provides a reciprocating skeleton oil seal and a low-friction shock absorber using the same, which can be fully and durably lubricated, has good sealing performance, and also enables the shock absorber to maintain a low friction.

[0005] For the reciprocating skeleton oil seal, the present application provides the following technical solutions:

[0006] The reciprocating skeleton oil seal of the shock absorber comprises a super-elastic sealing body and a metal skeleton, the metal skeleton comprises a main metal skeleton and a secondary metal skeleton, the main metal skeleton is fixed outside the super-elastic sealing body at a fixed position of a guide, the secondary metal skeleton is fixed outside the super-elastic sealing body at a position of sealing hydraulic oil, the inner surface of the super-elastic sealing body has a gas sealing lip at the upper end and a main lip and a secondary lip at the lower end, when the super-elastic sealing body is sleeved on the piston rod, the gas sealing lip is in interference fit with the piston rod, the main lip is in interference fit with the piston rod, and the secondary lip is in interference fit with the piston rod. The inner surface of the super-elastic sealing body, the main lip, and the secondary lip form a first micro groove, and the inner surface of the super-elastic sealing body, the gas sealing lip, and the secondary lip form a second micro groove, and the micro grooves can store lubricating grease. When designing the oil seal, the interference amount of the oil seal and the piston rod, the oil surface angle and the gas surface angle of the main lip, the gas surface angle of the secondary lip, and the gas sealing lip angle are mainly considered, and the following steps are used to determine them:

[0007] S1, first, the Shore hardness H of the super-elastic sealing body is detected A, further using Mooney-Rivlin model, according to formula C 01 = 0.25C 10 , The corresponding material parameters are calculated: E is the elastic modulus, v is the Poisson's ratio, C 10 and C 01 are model parameters, and D1 is the incompressible parameter. The metal skeleton adopts steel material. The cooperation between the piston rod and the oil seal is simulated by displacement loading. Considering the symmetry and calculation efficiency of the model, a 1 / 4 finite element model is established for calculation, and at the same time, in order to ensure the accuracy of the model, the piston rod, oil seal and other parts are all adopted three-dimensional 8-node hexahedral elements, and the full integration method is used for calculation. The super-elastic sealing body and the metal skeleton are adopted binding contact, and the piston rod and the super-elastic sealing body are adopted friction contact. For the convergence debugging process of the super-elastic material, the contact state needs to be adjusted, the large deformation switch is opened, and the multi-load step is used for displacement loading, so as to ensure that the contact quantity gradually increases and tends to be stable.

[0008] S2, the simulation outputs the node contact pressure distribution of the contact surface between the oil seal and the piston rod, and after arrangement, the formula is used to calculate the total radial force F r in the circumferential direction, including the recovery stroke and the compression stroke, and the unit is N. In the formula, d is the diameter of the piston rod, the unit is mm; p(x) is the distribution of the contact pressure along the piston rod, the unit is MPa; x is the distance from the oil side contact position, the unit is mm; b is the contact width, the unit is mm. Then the average friction force F of the oil seal when the piston rod reciprocates can be calculated.

[0009] S3, the initial oil seal parameters are interference δ=0.9mm, main lip oil surface angle α=50°, main lip gas surface angle β=25°, secondary lip angle γ=18°, and seal gas lip angle θ=20°. The oil seal structure parameter optimization is carried out through 5-factor 4-level orthogonal test design. The interference value is between 0.7-1.0mm, with an interval of 0.1mm; the main lip oil surface angle value is between 48-54°, with an interval of 2°; the main lip gas surface angle value is between 23-29°, with an interval of 2°; the secondary lip angle value is between 16-22°, with an interval of 2°; and the seal gas lip angle value is between 18-24°, with an interval of 2°. Through 16 groups of simulation calculation, the oil seal contact pressure and friction force of different parameters are obtained.

[0010] As preferred, in order to exclude the random factors of orthogonal test, explore the optimal level combination of each influencing factor, and analyze the primary and secondary order of the influence of each factor on the maximum contact pressure of the lip port position under different strokes and the minimum friction force between the piston rod and the oil seal, the range analysis method is used to analyze the results of 16 groups of orthogonal test. According to the results of the orthogonal test, first, the average value K of the test index of each factor at the same level needs to be calculated ij , and then the range R corresponding to the test index of each factor at the same level is calculated i = max{K ij} - min{K ij}, i is the factor in the orthogonal test table, and j is the level number corresponding to each factor. The larger the range is, the greater the influence of the factor on the target value is. Thus, the influence degree of each factor on the target and the optimal level value are determined. The improved oil seal parameters are determined as the interference amount δ = 0.7 mm, the main lip oil surface angle α = 48°, the main lip gas surface angle β = 23°, the secondary lip angle γ = 16°, and the seal gas lip angle θ = 24°. The optimization results are obtained and tested. Due to the machining error, the interference amount will have a deviation of 0.01 mm, and each angle will have a deviation of 0.2°.

[0011] As preferred, the reciprocating skeleton oil seal adds the lubricating grease after the oil seal is installed in the piston rod.

[0012] As preferred, the super-elastic sealing body is made of fluororubber, butadiene-acrylonitrile rubber or hydrogenated butadiene-acrylonitrile rubber.

[0013] As preferred, a plurality of first micro-grooves and second micro-grooves can be arranged on the annular sealing surface.

[0014] As preferred, the main metal skeleton and the auxiliary metal skeleton are fixed on the super-elastic sealing body through vulcanization.

[0015] As preferred, the calculable finite element model is established according to the recovery stroke and the compression stroke respectively. The piston rod is set as a solid entity with gradually increasing diameter to constant diameter, and the oil seal and the piston rod are in a default closed gap in the initial state.

[0016] As preferred, the parameter analysis considers the orthogonal design test scheme.

[0017] Compared with the prior art, the shock absorber of the present application can further reduce the friction force between the reciprocating skeleton oil seal and the piston rod of the shock absorber, improve the service life of the shock absorber, and improve the comfort performance of the shock absorber by optimizing the design of the reciprocating skeleton oil seal. BRIEF DESCRIPTION OF DRAWINGS

[0018] Figure 1 The structure of the shock absorber in the embodiment of the present application is shown in the structure of the shock absorber in the embodiment of the present application;

[0019] Figure 2 is Figure 1 a sectional view of a shock absorber in the application;

[0020] Figure 3 is a structure schematic diagram of a reciprocating skeleton oil seal in the application;

[0021] Figure 4 is a finite element model under different strokes;

[0022] In the figure: 1-upper lifting ring; 2-dust cover; 3-telescopic dust cover; 4-liquid storage cylinder; 5-lower lifting ring; 6-guide; 7-reciprocating skeleton oil seal, 71-super-elastic body, 72-main metal skeleton, 73-secondary metal skeleton, 74-air sealing lip, 75-second lip, 76-main lip, 77-first micro-groove, 78-second micro-groove; 8-inner buffer block; 9-guide bushing; 10-piston ring; 11-piston; 12-bottom valve; 13-working cylinder; 14-recovery nut; 15-piston rod; 16-compression bolt; 17-compression nut; 18-liquid storage cylinder cover. DETAILED DESCRIPTION

[0023] In order to better understand the purpose, structure and function of the application, the technical solutions of the application will be described clearly and completely in combination with the drawings. Obviously, the described embodiments are only part of the embodiments of the application, not all the embodiments. Based on the embodiments in the application, all other embodiments obtained by those skilled in the art without creative labor fall within the scope of protection of the application.

[0024] In the description of the application, it should be noted that the terms "upper", "lower", "inner", "outer" and the like indicate the orientation or positional relationship shown in the drawings, and are only for the convenience of describing the application and simplifying the description, and do not indicate or imply that the devices or elements referred to must have a particular orientation, be constructed and operated in a particular orientation, therefore it cannot be understood as a limitation of the application.

[0025] EMBODIMENT

[0026] Please refer to Figures 1-4In the embodiment, the low-friction shock absorber using the reciprocating skeleton oil seal comprises a liquid storage cylinder 4, the inner wall of the liquid storage cylinder 4 is fixedly connected with a working cylinder 13, the top end inner wall of the working cylinder 13 is fixedly connected with a guide 6, the guide 6 is in contact with a piston rod 15 through a guide bushing 9, and the guide 6 is fixedly installed with a reciprocating skeleton oil seal 7 above; a bottom valve 12 is fixed below the working cylinder 13, the bottom valve 12 forms an integral whole through a compression bolt 16 and a compression nut 17, a liquid storage cylinder cover 18 is fixed on the liquid storage cylinder 4 below the bottom valve 12; a lower lifting ring 5 is fixed below the liquid storage cylinder cover 18; the working cylinder 13 is internally provided with the piston rod 15, the bottom end outer surface of the piston rod 15 is fixedly connected with a piston 11 through a reset nut 14; the piston 11 is fixedly connected with a piston ring 10 in outer surface, and the piston 11 is fixedly provided with an inner buffer block 8 above; the liquid storage cylinder 4 is externally provided with a telescopic dust cover 3, and the telescopic dust cover 3 is connected with a dust cover cover 2 above; the dust cover cover 2 is fixedly provided with an upper lifting ring 1 above.

[0027] The reciprocating skeleton oil seal 7 comprises a super-elastic sealing body 71, a main metal skeleton 72 and a secondary metal skeleton 73, the main metal skeleton 72 is fixed outside the super-elastic sealing body 71 at a fixed position of the guide 6, the secondary metal skeleton is fixed outside the super-elastic sealing body 71 at a position of sealing hydraulic oil, the inner surface of the super-elastic sealing body 71 is provided with a main lip 76 and a secondary lip 75 at the lower end, and is provided with a gas sealing lip 74 at the upper end, when the super-elastic sealing body 71 is sleeved on the piston rod 15, the gas sealing lip 74 is in interference fit with the piston rod 79, the main lip 76 is in interference fit with the piston rod 15, and the secondary lip 75 is in interference fit with the piston rod 15. The inner surface of the super-elastic sealing body 71, the main lip 76 and the secondary lip 75 form a first micro groove 77, the inner surface of the super-elastic sealing body 71, the gas sealing lip 74 and the secondary lip 75 form a second micro groove 78, and the micro grooves can store lubricating grease.

[0028] In the embodiment, if the contact pressure is small when the reciprocating skeleton oil seal 7 is designed, the sealing property cannot be guaranteed, and if the friction is large, the use of the shock absorber is affected. In the embodiment, the interference amount of the oil seal and the piston rod, the oil surface angle and the gas surface angle of the main lip, the gas surface angle of the secondary lip and the gas sealing lip angle are determined through the following steps.

[0029] S1, first, the Shore hardness H of the corresponding rubber is detected A , further, the two-parameter Mooney-Rivlin model widely used in engineering is adopted, and the corresponding material parameters are calculated according to the formula C 01 =0.25C 10 , E is the elastic modulus, v is the Poisson's ratio, C 10 and C 01D1 is the incompressible parameter. The metal skeleton is made of steel material. The cooperation between the piston rod and the oil seal is simulated by displacement loading. Considering the symmetry and calculation efficiency of the model, a 1 / 4 finite element model is established for calculation. At the same time, in order to ensure the accuracy of the model, the piston rod, oil seal and other parts are all made of three-dimensional 8-node hexahedral elements, and the calculation is carried out by using full integration. The binding contact is used between the rubber and the metal skeleton, and the friction contact is used between the piston rod and the rubber. For the convergence adjustment process of the super-elastic material, the contact state needs to be adjusted, the large deformation switch is opened, and the multi-load step is used for displacement loading to ensure that the number of contacts gradually increases and tends to be stable.

[0030] S2, the node contact pressure distribution of the contact surface between the simulated output oil seal and the piston rod is arranged, and then the formula is used accordingly to calculate the total radial force F in the circumferential direction r , unit: N. In the formula, d is the diameter of the piston rod, unit: mm; p(x) is the distribution of contact pressure along the piston rod, unit: MPa; x is the distance from the oil side contact position, unit: mm; b is the contact width, unit: mm. Then the average friction force of the oil seal during the reciprocating motion of the piston rod can be calculated

[0031] S3, the initial oil seal parameters are interference δ = 0.9 mm, main lip oil surface angle α = 50°, main lip gas surface angle β = 25°, secondary lip angle γ = 18°, and gas sealing lip angle θ = 20°. The oil seal structure parameters are optimized by 5-factor 4-level orthogonal test design. The interference value is between 0.7 and 1.0 mm, with an interval of 0.1 mm; the main lip oil surface angle value is between 48 and 54°, with an interval of 2°; the main lip gas surface angle value is between 23 and 29°, with an interval of 2°; the secondary lip angle value is between 16 and 22°, with an interval of 2°; the gas sealing lip angle value is between 18 and 24°, with an interval of 2°. Through 16 groups of simulation calculation, the oil seal contact pressure and friction force of different parameters are obtained. In order to exclude the random factors of orthogonal test, explore the optimal level combination of each influencing factor, and analyze the primary and secondary order of the influence of each factor on the maximum contact pressure of the lip position and the minimum friction force between the piston rod and the oil seal under different strokes, the range analysis method is used to analyze the results of 16 groups of orthogonal test. According to the results of orthogonal test, first, the average value K ij of the test index of each factor at the same level needs to be calculated i ij , and then the range R ij ​} is a factor in the orthogonal test table, j is the level number corresponding to each factor. The greater the range, the greater the influence of the factor on the target value. The influence of each factor on the target and the optimal level value are determined. The improved oil seal parameters are interference amount delta = 0.7mm, main lip oil surface angle alpha = 48 degrees, main lip gas surface angle beta = 23 degrees, secondary lip angle gamma = 16 degrees, and seal gas lip angle theta = 24 degrees. The optimization result is obtained and tested. Due to the machining error, the interference amount will have a deviation of 0.01mm, and each angle will have a deviation of 0.2 degrees.

[0032] In the embodiment, the super-elastic body of the reciprocating skeleton oil seal 7 is made of fluororubber, CR rubber or hydrogenated CR rubber.

[0033] In the embodiment, the telescopic dust cover 3 is made of rubber material and can prevent external dust from entering the inside of the working cylinder barrel 13.

[0034] In the embodiment, the first micro groove 77 and the second micro groove 78 can be arranged on the annular sealing surface.

[0035] In the embodiment, the main metal skeleton 72 and the auxiliary metal skeleton 73 are fixed on the super-elastic sealing body 71 through vulcanization.

[0036] In the embodiment, the guider 6 is pressed into the guide bushing 9, so as to reduce the friction between the guider 6 and the piston rod 15 and play a guiding role. The guide bushing 9 is made of filled bronze polytetrafluoroethylene composite material injection molding.

[0037] In the embodiment, the piston 11 is provided with the piston ring 10, so as to reduce the friction between the piston 11 and the inner wall of the working cylinder 13 and play a guiding and sealing role. The piston ring 10 is made of filled bronze polytetrafluoroethylene composite material injection molding.

[0038] In the description of the present application, the terms "comprising", "containing" or any other variant thereof are intended to cover non-exclusive inclusion, so that the process, method, article or equipment including a series of elements not only includes those elements, but also includes other elements not explicitly listed or inherent to such process, method, article or equipment. Without more limitation, the element defined by the statement "comprising a reference structure" does not exclude the presence of another same element in the process, method, article or equipment including the element. It should be noted that in this paper, the relationship terms such as "first", "second" and the like are only used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any such actual relationship or order between the entities or operations.

[0039] Finally, it should be noted that the above only describes the preferred embodiments of the present application and is not intended to limit the present application. Although the present application has been described in detail with reference to the foregoing embodiments, those skilled in the art will appreciate that the technical solutions described in the foregoing embodiments can be modified or some technical features thereof can be replaced by equivalent ones. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present application shall be included in the protection scope of the present application.

Claims

1. A reciprocating skeleton oil seal characterized by: The super-elastic sealing body (71), the main metal skeleton (72), and the secondary metal skeleton (73); the main metal skeleton (72) is fixed outside the super-elastic sealing body (71) and is located at the fixed position of the guide (6), and the secondary metal skeleton (73) is fixed outside the super-elastic sealing body (71) and is located at the position of the sealing hydraulic oil. The inner surface of the super-elastic sealing body (71) has a main lip (76) and a secondary lip (75) at the lower end, and has a gas sealing lip (74) at the upper end; when the super-elastic sealing body (71) is sleeved on the piston rod (15), the gas sealing lip (74) is in interference fit with the piston rod (79), the main lip (76) is in interference fit with the piston rod (15), and the secondary lip (75) is in interference fit with the piston rod (15). The inner surface of the super-elastic sealing body (71), the main lip (76), and the secondary lip (75) form a first micro groove (77), and the inner surface of the super-elastic sealing body (71), the gas sealing lip (74), and the secondary lip (75) form a second micro groove (78). The interference amount between the main lip, the secondary lip, and the piston rod, the oil surface angle and the gas surface angle of the main lip, the gas surface angle of the secondary lip, and the gas sealing lip angle are determined by the following steps: S1, first detect the Shore hardness H of the super-elastic sealing body A , using the Mooney-Rivlin model, according to the formula , the corresponding material parameters are calculated: E is the elastic modulus, v is the Poisson's ratio, C 10 and C 01 are model parameters, D1 is the incompressible parameter, and the metal skeleton is made of steel material; The interference fit between the piston rod and the oil seal is simulated by displacement loading, a 1 / 4 finite element model is established for calculation, three-dimensional 8-node hexahedral elements are used for the parts, and full integration is used for calculation; the binding contact is used between the super-elastic sealing body and the metal skeleton, and the friction contact is used between the piston rod and the super-elastic sealing body; S2, the node contact pressure distribution of the simulated output oil seal and piston rod contact surface is used to calculate the average friction force of the oil seal when the piston rod reciprocates F = 2 * p(x) * b * d r , where d is the diameter of the piston rod; p(x) is the distribution of the contact pressure along the piston rod; x is the distance from the contact position on the oil side; b is the contact width; and then the average friction force of the oil seal when the piston rod reciprocates is calculated S3, determine the initial oil seal parameters, including interference δ, main lip oil surface angle α, main lip gas surface angle β, secondary lip angle γ, and gas sealing lip angle θ; the oil seal structure parameters are optimized by 5-factor 4-level orthogonal test design, wherein the interference value is between 0.7-1.0mm, the interval is 0.1mm; the main lip oil surface angle value is between 48-54°, the interval is 2°; the main lip gas surface angle value is between 23-29°, the interval is 2°; the secondary lip angle value is between 16-22°, the interval is 2°; the gas sealing lip angle value is between 18-24°, the interval is 2°, and the oil seal contact pressure and friction force of different parameters are obtained by 16 groups of simulation calculation; S4, the results of the 16 groups of orthogonal test are analyzed by range analysis method; for the results of the orthogonal test, first, the average value K of the test index of each factor at the same level is calculated ij , then the range R corresponding to the test index of each factor at the same level is calculated i = max{K ij} - min{K ij}, i is the factor in the orthogonal test table, j is the level number corresponding to each factor; the greater the range is, the greater the influence degree of the corresponding factor on the target value is, thereby the influence degree of each factor on the target and the optimal level value are determined.

2. The reciprocating skeleton oil seal according to claim 1, wherein The first micro groove (77) and the second micro groove (78) are provided on the annular sealing surface.

3. The reciprocating skeleton oil seal according to claim 1, wherein The super-elastic sealing body (71) is made of fluororubber, nitrile rubber, or hydrogenated nitrile rubber.

4. The reciprocating skeleton oil seal according to claim 1, wherein The main metal skeleton (72) and the secondary metal skeleton (73) are fixed on the super-elastic sealing body (71) by vulcanization.

5. The reciprocating skeleton oil seal according to claim 1, wherein The calculable finite element model is established according to the recovery stroke and the compression stroke respectively; the piston rod is set to be a solid with gradually increasing diameter to constant diameter, and the oil seal and the piston rod are in default closed gap in the initial state.

6. The reciprocating skeleton oil seal of claim 1, wherein The initial oil seal parameters are interference δ=0.9mm, main lip oil surface angle α=50°, main lip air surface angle β=25°, secondary lip angle γ=18°, and seal air lip angle θ=20°; and the finally determined oil seal parameters are interference δ=0.7mm, main lip oil surface angle α=48°, main lip air surface angle β=23°, secondary lip angle γ=16°, and seal air lip angle θ=24°.

7. A low-friction shock absorber employing the reciprocating skeleton oil seal according to any one of claims 1 to 6, characterized by The device comprises a liquid storage cylinder (4), an inner wall of the liquid storage cylinder (4) is fixedly connected with a working cylinder (13), a top end inner wall of the working cylinder (13) is fixedly connected with a guide (6), the guide (6) is in contact with a piston rod (15) through a guide bushing (9), and a reciprocating skeleton oil seal (7) is fixedly installed above the guide (6); a bottom valve (12) is fixed below the working cylinder (13), the bottom valve (12) forms an integral whole through a compression bolt (16) and a compression nut (17), a liquid storage cylinder cover (18) is fixed on the liquid storage cylinder (4) below the bottom valve (12); a lower lifting ring (5) is fixed below the liquid storage cylinder cover (18); the working cylinder (13) is internally provided with the piston rod (15), an outer surface of a bottom end of the piston rod (15) is fixedly connected with a piston (11) through a recovery nut (14); an outer surface of the piston (11) is fixedly connected with a piston ring (10), and an upper portion of the piston (11) is fixedly connected with an inner buffer block (8); a telescopic dust cover (3) is arranged outside the liquid storage cylinder (4), and the telescopic dust cover (3) is connected with a dust cover cover (2) above; an upper lifting ring (1) is fixed above the dust cover cover (2).

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