Analysis of the ironing of a BJ-type constant velocity joint outer race with the upper bound element method

Abstract A constant velocity joint outer race is an important load-supporting part in cars, which transmits torque between the transmission gear box and the driving wheel. The outer race is difficult to be forged because its shape is very complicated and its required precision is high. There is no mature technology, especially no cold and warm forging process, to produce this component in China. In order to meet the demands of Chinese automobile industry, the Science Committee of China approved a project named “Development of Constant Velocity Joint Outer Race with Cold and Warm Forging Technology” in 1995. It is one of the key projects in the ninth five-period of China, and is in the charge of Beijing Mechanical and Electrical Research Institute. The key of forging the outer race is how to implement its ironing. This paper analyzes the cold and warm forming of the ironing process of the outer race, in order to offer a theoretical basis for die designing and the choice of press, with the upper bound method. The paper deduces the general equations for computing the forming force and punch pressure for the problem of the ironing of the outer race. In order to testify these equations, this paper computes the numerical solution of the ironing force of the outer race of a Santana car.