螺杆钻具挠性轴强度校核及干涉量计算

Strength check and interference calculation of flexible shaft on screw drill

螺杆钻具挠性轴设计中的两个主要问题是强度校核和干涉量计算。应用纵横弯曲梁柱理论求解挠性轴的弯矩及变形量，应用数值计算法研究挠性轴自身惯性力对挠性轴的最大弯矩及变形量的影响，计算结果表明，在挠性轴较长时，影响较大，不能忽略不计。挠性轴强度校核主要是校核疲劳强度，为此提出了合理设计挠性轴的原则，即挠性轴的疲劳强度应取决于扭转疲劳强度。若疲劳强度取决于弯曲疲劳强度，则可增加挠性轴的长度，且挠性轴最佳直径为满足强度要求的最小值。为确保挠性轴的使用安全性，给出了干涉量计算式。

The main Problems with designing the flexible shaft on a screw drill are strength check and interference calculation.The bending moment and deformation of the flexible shaft are calculated by using the crossbar bending beam theory, and the influence of the self inertial force of the shaft on the shaft's maximum bending moment and deformation is investigated by the numerical method. The calculating result shows that the influence is fairly great and cannot be ignored when the shaft is long. Therefore the design criterion for the shaft is proposed, i. e. the fatigue strength of the shaf should depend on the torsional fatigue strength. If the fatigue strength depends on the bending fatigue strength, the length of the shaft can be increased, and the optimum diameter of the shaft is the mimimum value satisfying the strength requirement. To ensure safe service, the equation for calculating the interference of the shaft is presented.