Finite Element Analysis and Optimization of High Speed E-mobility Seal

Abstract

Background: The use of electric vehicles is expected to increase day by day. The operating conditions of the rotary shaft seals used in the powertrain of electric vehicles are more challenging than those of internal combustion engines. The maximum operating temperature of seal used in electric vehicles is 150℃ and the maximum operating speed is 16,000RPM. It is impossible for a standard seal with a garter spring not to leak under these operating conditions, which has led us to turn to alternative designs. Objective: The objective of starting this study is to develop a new generation rotary shaft seal to be used in electric vehicles with finite element analysis (FEA) and optimization. Methods: During this study, finite elements, optimization and geometry development methods were used. First of all, alternative spiral knurled seal that can operate at high speeds was designed in this study. Secondly, our alternatively designed seal was tested to determine lifetime. Results: When we checked the results coming from test machines, the first design seal had approximately 5g of leakage at the end of 7 days. In the examinations made after the experiment, it was observed that the spirals were deleted at the end of 7 days. A finite element model of the first designed seal was created and radial load control was performed. When the radial load value obtained from the finite element model and the experimental radial load value are compared, it is seen that there is a deviation of around 4.3%. In the light of these data, the accuracy of the FEA model created in the Abaqus has been proven. The created finite element model was optimized within the boundary conditions with the help of Isight. A prototype of the optimized design seal was produced and a life-time test was carried out. The prototype seal of the optimized design had approximately 4g of leakage after 13 days under the same test conditions. Since the lifetime requested by the customer is 10 days, the optimization made on the seal is considered appropriate. The lifetime of the seal was approximately 95% improved. Conclusion: As a result, a new generation rotary shaft seal that can be used in electric vehicles, which is the aim of our study, has been developed. The prototype rotary shaft seal has been validated according to DIN 3761 specification.