Spiral profile design and parameter analysis of flexure spring Original Research Article

Universal design method of spiral flexure spring has been generalized firstly. Through adjusting the space location of spiral arms together with parameters of individual spiral profile including base radius, involute pitch, involute angle, start angle of involute, width of slot, various spiral flexure springs with different performances can be obtained respectively. Then the finite element program, whose validity has been verified by experimental data, is used to analyze the performance of the flexure spring. Furthermore experimental study of the spring assembly reveals the superimposed effect of stiffness and the antitorque characteristic of spring stack, which had been ignored previously. Finally, in order to get the general relation between the axial stiffness, natural frequency of flexure spring and its geometry parameters, the theoretical model, which is based on the mechanics of material and vibration, has been set up and subsequently solved. The validity of derived expressions has been proved by finite element program and published experiment data respectively. Those induced expressions are more convenient and direct than finite element method and can be served as the guide to designation of flexure spring.