Research And Improvement On Sealing Performance Of Transmission Connector Under High Temperature Rise Conditions

With the rapid development of Chinese automotive industry,the application of connectors in automotive electrical circuits has become more and more extensive,and the demand for connector reliability has become increasingly prominent.There are many application scenarios for connector sealing,such as inside the engine,underwater,etc.Targeted analysis and design are required to ensure the operating life and reliability of sealing materials,as the sealing performance of them under high temperature rise conditions is challenged due to the thermal expansion and contraction,In this paper,the cylinder-through connector of automobile gearbox is taken as the object,and its sealing performance is researched by a combination of theoretical calculation and simulation analysis.At the same time,the design and preliminary verification of the improved scheme for the weak link in the realization of sealing have been carried out.The main contents of the research are as follows:First,the transmission connector model is established and the model is specifically simplified according to the sealing structure.It is pointed out that the interference connection between the pin and the lower part of the housing is the main structure to realize the oil seal of the tank.The sealing mechanism and influencing factors of connector are analyzed.The specific pressure is selected as the key indicator of the connector sealing,and the sufficient sealing specific pressure and small plastic deformation of the sealing surface should be ensured in the automobile operation environment.Secondly,the connector model is analyzed by using the thick-walled cylinder theory for stress analysis of thick-walled containers in material mechanics.The relational formula of the equivalent effect force of the interference is obtained.The elastic-plastic deformation of materials is considered and the equivalent stress of the sealing surface is solved by the bilinear method.The thermal expansion theory is also used to calculate the stress changes caused by the thermal deformation under high temperature rise conditions.The maximum stress of the sealing surface corresponding to different shell wall thicknesses under high temperature environments is obtained by the simultaneous thick-walled cylindrical model.Then,the finite element software is used to simulate the sealing performance of the connector.The equivalent stress,plastic deformation,and radial stress distribution at the mating position of the male housing and pins are obtained.The limit temperature is introduced to analyze the change law of sealing performance under temperature rise conditions,and the sealing state is compared with the initial sealed state.The simulation results show that the sealing pressure distribution of the connector is uneven under the influence of the shell shape and external constraints.The sealing faces near the lower end surface are more prone to insufficient radial stress and excessive plastic deformation.Large temperature rise will weaken the sealing effect on the oil,and the contact interface leakage channel may expand.Therefore,there is a need to improve the sealing performance.Finally,for the weak positions of the seal,applying a surface texture to the pin body is considered to improve the seal.Taking the pit texture as an example,the effect of the surface texture on improving the reliability of the connector is analyzed.According to the connector size,geometric parameters such as the depth and radius of the single pit texture are designed and preliminarily verified by simulation.The simulation results confirm that the introduction of pit texture significantly improves the sealing performance of the connector.