抽油机曲柄销失效分析及联接设计

分析了游梁式抽油机曲柄销所受载荷及失效形式。指出曲柄销失效的主要原因是曲柄销和锥套的过盈配合面之间出现了松压现象，这种松压现象是由曲柄销受灾变载荷作用所引起，且失效主要发生在曲柄销锥面中部台阶、螺纹根部及锥面小端三处，破坏形式则以弯曲疲劳破坏为主，螺纹根部的破坏具有扭转破坏的特征。提出了曲柄销与曲柄联接的设计准则及螺纹预紧力矩的计算公式。

Failure analysis and connection design of pumping unit crank pin

The load applied on the crank pin of a beam pumping unit and the failure patterns of the pin are analyzed.It is pointedout that the failure of the pin is mainly caused by the looseness of the interference fit between the pin and the taper sleeve dueto the alternating load applied on the pin, and the failure occurs mainly at the shoulder of the pin's tapered surface, the rootof the threads and the small end of the tapered surface.It is principally the bending fatigue failure and at the thread root thetorsion failure.The design criterion of the connection between the crank pin and the crank and the equation for calculating the pretightening torque on the threads are presented.