球面对锥面特殊螺纹气密封性能影响因素分析

针对油套管特殊螺纹球面对锥面密封结构，基于Hertz接触力学理论和密封接触能机理，建立了考虑密封面作用扭矩的特殊螺纹气密封压力计算理论模型，研究了球面半径、锥面锥度和密封面作用扭矩对螺纹气密封性能的影响规律，结果表明：随着球面半径增大，螺纹气密封压力呈幂指数规律降低；随锥面锥度增大，螺纹气密封压力逐渐降低，但降幅较小；随密封面附加上扣扭矩增加，螺纹气密封压力呈抛物线型增大。总体来看，球面半径和密封面附加上扣扭矩对特殊螺纹气密封性能影响显著。建议一方面优化球面半径，另一方面合理控制密封面作用扭矩，使得密封接触应力分布既能满足足够的气密封能力，又能保证密封面不发生屈服。

Analysis of Factors Influencing Hermetic Seal Performance with a Spherical-conical Surface and Special Screw Threads

A theoretical model for calculating the hermetic seal pressure of special screw threads subjected to an applied torque from a spherical-conical sealing surface is established. The influence of the spherical radius, cone and taper, and applied torque of the sealing face are studied. According to the results, the hermetic seal pressure of the screw threads declines according to a power law with increasing spherical radius; the hermetic seal pressure declines gradually with an increase in the cone and taper; and the hermetic seal pressure increases parabolically with increase in the make-up torque added to the sealing surface. Generally, the spherical radius and make-up torque added to the sealing surface have a significant impact on the hermetic seal performance of the special screw threads. It is suggested to optimize the spherical radius while properly controlling the applied torque such that the stress distribution of the sealed contacts can simultaneously satisfy the hermetic seal performance and stop the yielding of the sealing surface.