摘要:Torsion bar design is very important on Electrical power steering(EPS) development. The mathematical model and structure for torsion bar are developed, and the torsion bar outer spline is cancelled based on the automotive parameters. This kind of structure leads to cost down and time saving on torsion bar manufacturing process. The 3D model and finite element on sub-EPS(torsion bar, input shaft, output shaft) are developed, and then do the contact nonlinear analysis based on interference between torsion bar and output shaft. The EPS structure and test reliability according to function test and durability test are verified and the test results are passed.