在对承受扭转与表面残余应力的圆柱螺旋压缩弹簧任意截面所作的应力分析的基础上得出,与弹簧线材轴线成α=135°斜截面上的为最大正应力。因此这类弹簧的疲劳开裂大多起裂于内圆表面,沿α=135°斜截面扩展并导致疲劳断裂。但表面形变强化引入表面α=45°方向的残余压应力σr,α,能有效地降低外施扭转切应力在斜截面上(α=135°)的最大正应力水平,从而使弹簧的疲劳断裂抗力得以提高。

On the basis stress analysis for both applied torsional and residual compressive stress on the arbitrary section of cylindrical helical compression spring,it is found out that the maximum direct stress is appeared in the inclined section under an angle of α=135° with the wire axis of spring. Therefore the fatigue cracks initiate almost at the inner surface of spring and propagate along the inclined section with α=135° inducing finally the fatigue fracture,However,the maximum direct stress can be effectively decreased by surface residual compressive stress σr,α in the direction of α=45° with the wire axis of spring introduced by shot peening,which may increase the fatigue resistance of spring.