钻具螺纹接头螺纹牙载荷计算方法的探讨

钻具螺纹接头各圈螺纹牙承受的载荷分布是不均匀的，这对螺纹接头的疲劳强度影响很大。用有限元分析方法虽能精确地计算许多条件下螺纹牙的受力状况，但要系统分析各种因素对螺纹牙承受载荷的影响就不太方便。鉴于此，用数学分析方法得到了在预紧扭矩和外加轴向载行作用时钻具螺纹接头的变形协调方程，并求出其近似解，即螺纹各圈间载荷分布函数，据此讨论了影响各圈螺纹牙载荷分布的因素。分析认为，减小内、外螺纹接头截面积倒数之和，或增大螺纹牙啮合时的变形柔度，可使各圈螺纹牙载荷分布趋于均匀。

Method for calculating load on threads of drill tool connection

Loads on tile thread of drill tool connection are not evenly distributed, and this has great influence on the fatiguestrength of the threaded joints. The force condition of the thread under many conditions can be calculated accurately bythe finite element method, but it is inconvenient to make a systematic analysis of the influence of various kinds of factorson loads on the thread. The equation of coordinated deformation of drill tool threaded joints with pretightening torque andadditional axial load is derived by the mathematical analysis method, and the approximate solution, which is the thread load distribution function, is obtained, thereby the factors influencing the thread load distribution are discussed. Analysisshows that, when the sum of the reciprocal values of the cross section areas of the pin and box connections is decreased,or the flexibility of the thread deformation in engagement is enlarged, the distribution of the thread loads is more uniform.