Lubrication And Sealing Performance Of Dynamic Pressure Seal With Combination Of Deep And Shallow Grooves

The working conditions in the high-speed bearing cavity are complicated,and a seal that can operate for a long time in both contact and non-contact conditions is urgently needed.Based on the traditional shallow groove dynamic pressure seal,this paper proposes a dynamic pressure seal with combination of deep and shallow grooves(DPS-DASG)that has good lubrication characteristics and sealing performance in all operating conditions.From the aspects of lowspeed lubrication characteristics and high-speed sealing performance,a systematic study on the performance and changing laws of the seal under full operating conditions has been carried out.Considering the mutual influence between multiple physical fields,the Archard equation and the Reynolds equation are solved,and the multi-field coupling analysis model of the combined dynamic pressure seal of deep and shallow grooves is established in full operating conditions.Obtain the lowspeed contact state end surface wear distribution and high-speed non-contact end surface film pressure distribution,which provides a theoretical basis for the calculation of the contact end surface lubrication characteristics and non-contact sealing performance.The experiment compares the lubrication characteristics of the end face of the DPS-DASG,and found that the combined structure of the deep and shallow groove can reduce the friction coefficient of the end face.The numerical analysis method is used to analyze the influence of the end face structure parameters on the friction and wear performance.Based on the orthogonal method,the value of the end face structure parameters when the wear rate and the peak temperature are comprehensively optimized is obtained,which provides an analysis basis for the seal friction and wear prediction and design.The influence of pressure,speed and structural parameters on the sealing performance is analyzed,and the response surface method is used to optimize the sealing performance with multiple parameters,and the value of the structural parameters of the end face when the sealing performance is comprehensively optimal is obtained.The sensitive factors of the sealing performance are the deep groove chord distance,the number of deep grooves and the ratio of groove to weir.Analyzing the influence of machining error on sealing performance,revealing the law of it weakening the dynamic pressure sealing performance,the research results provide an analysis basis for the calculation and design of sealing high-speed sealing performance.Set up a bearing cavity dynamic pressure seal test bench,and compare the leakage,temperature rise and vibration characteristics of the combined deep and shallow groove dynamic pressure seal and the shallow groove dynamic pressure seal by using the test method.The test results show that as the speed increases,the leakage rate of the DPS-DASG gradually decreases,and the DPS-DASG has a smaller temperature rise than the shallow groove dynamic pressure seal and the sealing operation is stable.When the number of deep grooves is small,the change of the number of deep grooves has little effect on seal vibration.Compared with the traditional shallow groove dynamic pressure seal,the DPS-DASG improves the end face wear under low speed conditions and reduces the seal temperature rise under high speed conditions on the basis of ensuring low leakage and small vibration.In this paper,numerical and experimental analysis methods are used to study the lubrication characteristics and performance of the end face of the DPS-DASG under all working conditions,which can provide theoretical and technical support for solving the sealing problems of high-speed bearing chambers under complicated working conditions.