中文摘要：

板弹簧技术是航空航天用斯特林制冷机长寿命、高可靠运行的关键技术之一。大的板弹簧径向刚度为活塞提供支撑,以保证活塞在极小的间隙内实现与汽缸之间的无接触运动;板弹簧轴向刚度为活塞直线运动提供轴向的自由度,其轴向的最大行程受到板弹簧材料疲劳极限的限制;由于没有活塞环等密封元件,高低压之间的密封通过活塞与气缸之间的间隙密封来实现,这大大提高了活塞和气缸间的装配难度。本文针对3种常见的板弹簧：同心涡旋臂板弹簧、偏心涡旋臂板弹簧和直线臂板弹簧进行有限元分析。通过改变板弹簧载荷、厚度和弹簧臂宽度等参数,对3种型式的板弹簧分别进行加载求解,得到弹簧的应力和位移分布云图。通过模态分析得到板弹簧的自然频率,为有效避免板弹簧的谐振提供依据。分析表明：在基本结构参数相同的情况下,直线臂板弹簧可以提供较大的径向刚度与轴向刚度之比和较高的自然频率,有利于整机系统的轻量化。

英文摘要：

The flexure bearings are one of the key components with long life,high reliable stirling cryocoolers for the aerospace use.The large radial stiffness of the spring provides a support for piston to ensure it works in a non-contact way with cylinder.The small axial stiffness of the flexure bearing ensures the piston working freely in the cylinder.The largest axial displacement is limited by the material fatigue limit restrictions.Because of the absence of the piston ring,the seal between the cylinder and the back volume is pressurized by the clearance gap,thus improving the piston and cylinder assembly technology.In this paper,three common flexure bearings including concentric flexure bearings,eccentric flexure bearings and linear arm flexure bearings are analyzed by FEM software.By changing the load,the thickness and the width of flexure bearing,the three types of plate spring are solved,and results of stress and displacement contours are shown.By using the modal analysis,the natural frequency is obtained to avoid the resonance nature frequency of spring.Analysis results show that on the same basic structure,the linear arm flexure bearings provide the largest axial and radial stiffness,and the highest natural frequency,thus it is conductive to the lightweight of the whole cryocooler system in aerospace use.