| Rotary seal is the key component of the vehicle transmission system,which is used to prevent the hydraulic oil from leaking in the gap between the rotating parts and the static parts,and consequently,maintain the stability of the oil pressure.The expanding ring is assembled in the ring groove of the shaft.And two pairs of sealing faces are formed by pressing against the inner cylindrical surface of the bushing and the end face of the ring groove.At present,the driving device of the vehicle is developing towards high speed and miniaturization,and the technical performance requirements of the rotating sealing component in the driving system also need to be improved.In such a development trend,the lubrication condition of sealing surface is easy to deteriorate,and the sealing couples are difficult to achieve the expected design requirements and service life.To improve the contact state between the expanding ring and the end face of the ring groove and to reduce the friction coefficient between the friction pairs is one of the important means to solve the premature failure of the rotating oil seal ring in the mechanical transmission device.The results show that the surface texture has been widely used to improve the tribological properties of friction pairs.By machining the array texture on the narrow groove end face,the friction and wear resistance of the expanding ring can be reduced,and the service life of the expanding ring can be increased.In addition,the replacement times of the expanding ring can be reduced.Therefore,it is necessary to carry out the theoretical and experimental research on the texture design and processing technology of the end face of the shaft groove,which is of great significance to extend the service life of the seal ring,reduce the maintenance cost,and improve the operation safety and service stability of the transmission device.In this paper,the research on the design and machining requirements of the anti-wear texture of the end face of the shaft groove for the high-performance rotary seal was carried out.The simulation model of rotating dynamic seal considering the fluid structure interaction between friction pairs was established.The anti-friction property of the texture between PEEK and the textured 38 CrSi alloy steel was studied.In addition,the influence of geometric characteristics and machining accuracy on the anti-friction performance was clarified.In order to solve the problem of high precision machining of texture in narrow space,anelectrochemical machining fixture and device were developed,which can realize the controllable and efficient machining of the texture characteristics of the end face array of the shaft groove.Based on the features of machined surface morphology,the anti-friction effect of axial groove end face array texture was proved.The main research contents and conclusions of this paper are as follows:(1)A simulation model of rotating dynamic seal considering the fluid structure coupling between PEEK seal ring and 38 CrSi alloy steel was established.Through the simulation model,it is clear that the optimal combination of the texture parameters of the end face of the shaft groove under the actual working condition is a cylindrical micro pit with a diameter of 400 μm,a depth of 10 μm and an area ratio of 20%.In addition,the processing accuracy indexes of the texture size were clarified.The relative deviation of the diameter and the depth are 40 μm and 5 μm respectively.The diameter of the bottom of the texture has no obvious effect on the results.(2)The effect of the surface texture of the friction pair composed of textured 38 CrSi alloy steel and PEEK polymer on the tribological properties was studied.An electrochemical machining fixture and device for the efficient machining of the array texture on the surface of the test disk were developed.The uniform texture with an average diameter of 330 μm and a depth of 13 μm was obtained and the friction coefficient was reduced by 5% compared with that without texture.(3)An electrochemical machining fixture and device were developed,which can realize the controllable texture and high efficiency machining of the narrow end face array.The processing of uniform texture with an average diameter of 300 μm and a depth of 10 μm was realized.Compared with the friction coefficient without texture,the actual texture was reduced by 17%,which proves that the end texture of the shaft groove has a better friction reduction effect. |
