螺栓的冲击载荷分析

预紧螺栓所受拉力可根据力平衡和螺拴与被联接零件间的变形协调条件确定，其大小变化量为外加载荷变化量的几分之一。但当外加载荷是通过几个联接处有较大间隙的零件传递至螺栓时，这种分析方法就不再适用。由于间隙的存在，零件间的运动速度不协凋，间隙消除时必然产生冲击，使螺栓承受冲击载荷。准确计算冲击载荷的大小对于螺栓的使用安全具有重要意义。某离合器式螺旋压力机的预紧联接螺栓，承受着螺杆和滑块重量、平衡回程缸下推力以及滑块回程制动期间较强的冲击力。文中通过分析制动期间螺旋副的冲击过程，建立螺栓变形的数学模型，导出冲击载荷解析式，提出降低冲击载荷的措施，为离合器式螺旋压力机回程制动机构的设计提供重要的参考，同时也为承受大惯性负载的螺旋机构的受力分析提供参考。

ANALYSIS OF IMPACT LOAD ON BOLTS

The tensile load of preloaded bolt, often a fraction of external load, could be determined according to the static equilibrium and deflection coordination between the bolt and the clamped parts. But this method is not suitable for the case where the external load is transmitted via a chain of parts with clearances existing at their joints. Due to the clearance, the speed of each part is not identical or coordinated, and impact will be occurred while the clearance is diminished, resulting in the application of impact load to the bolt. Exact calculation of the impacting load on bolt is of vital importance to the safety of the bolt. Bolts of a clutch screw press (CSP) bear weight of screw rod and slide of the CSP, balance the down-pushing force of return cylinder and balance strong impact load during the braking of the slide. In this article, an analysis is made of the impact of the screw pair and the braking process of the slide, a mathematical model of the impact load onto the bolts is established, a digital simulation is carried out, and measures is suggested to reduce the impact load. Therefore, the work done in this article can be an import reference to the design of return and brake mechanism of CSP, and also to the load analysis of screw drive bearing large inertial load.