交叉簧片式柔性铰链由两根不在同一几何平面内的细长簧片交错布置而成,且两簧片关于铰链长度方向的中心线对称布置,具有转动范围大、精度高等优点.交叉铰链中两簧片均可以看作是末端受力和弯矩组合作用的细长梁,变形情况较为复杂,因此难以对其进行精确建模.通过对簧片分别应用所推导的大挠度梁完备椭圆积分解,给出交叉铰链的精确分析模型和应力校核计算方法.结合两种交叉铰链的设计实例,揭示这类铰链在转角大于30°的情况下刚度非线性显著增强的特性,分析簧片存在拐点的变形情况,并对大转角变形下的交叉铰链进行强度校核.利用有限元软件对交叉铰链进行非线性分析,其分析结果与完备椭圆积分解建模结果吻合较好.
The cross-spring pivot consists of two leaf springs which are located in two different planes and arranged crosswise.The cross-spring pivot offers many advantages including large rotation range and high precision.Each of the leaf spring in a cross-spring pivot can be considered as a thin beam subject to combined end force and end moment,so its deflected configuration is quite complex and is difficult to be modeled.The cross-spring pivot is precisely modeled by using the comprehensive elliptic integral solution for the large deflection problem derived in our previous work and the stress check method is given.The model is used to analyze two different cross-spring pivots.The simulation results show that the nonlinearity of the stiffness of this kind of pivot becomes remarkable when the deflected angle is larger than 30°.The cases that the deflected configurations of the leaf springs carry inflection points are presented.The strength of each cross-spring pivot at large deflected angle is checked.The finite element software is also used to analyze the nonlinear deflections of cross-spring pivot,which results are well agreed with the model of the comprehensive solution.