考虑弹性变形的行星滚柱丝杠接触特性

Contact Characteristics of Planetary Roller Screw Mechanism Considering Elastic Deformation

为揭示行星滚柱丝杠螺纹承载产生弹性变形对螺旋曲面接触特性的作用机理,根据行星滚柱丝杠结构特点与承载原理,提出了一种可同时考虑丝杠、滚柱和螺母受力变形和不同螺纹接触侧载荷分布规律的螺旋曲面接触位置计算方法。基于行星滚柱丝杠传动原理和螺旋曲面相切接触条件,系统构建考虑弹性变形时丝杠、滚柱和螺母的螺旋曲面方程和螺纹接触方程。通过与现有模型接触位置参数计算结果对比,验证了所建模型的正确性。同时考虑受力变形和螺纹牙载荷分布规律,研究了载荷分布对内外啮合螺旋曲面接触半径和接触偏角的影响规律。结果表明,在弹性变形的作用下,内外啮合螺纹牙的接触点位置是变化的,丝杠-滚注侧接触点在偏离丝杠和滚柱中心连线的同时,逐渐向滚柱中径和丝杠大径方向移动;螺母-滚柱侧螺纹的接触点位置逐渐远离两者中径节圆的切点处,并且接触位置总是沿着滚柱中径节圆移动。

In order to reveal the mechanism between the elastic deformation of the thread teeth and the contact characteristics of helical surface,a calculation method for the contact position is proposed.The method is mooted based on the structural characteristics and load bearing principle of the planetary roller screw mechanism,which can simultaneously consider the deformation of the screw,roller and nut and the load distribution law of different thread contact sides.Based on the transmission principle of planetary roller screw mechanism and the tangent contact condition of helical surface,the helical surface equation and thread contact equation of screw,roller and nut considering elastic deformation are systematically constructed.The correctness of the established model is verified by comparing the calculation results of contact position parameters with existing models.The influence of load distribution on the contact radius and contact deflection angle of internal and external meshing helical surface is studied by considering the elastic deformation and the load distribution law of thread teeth.The results show that under the influence of elastic deformation,the contact positions of each pair of meshing thread teeth are constantly changing.The contact points between the screw and roller gradually move towards the direction of the middle diameter of roller and the major diameter of screw in addition to deviating from the center line of the screw and the roller.The contact points of nut-roller gradually move away from the tangent point of the pitch circle of the nut and roller,and the contact position always moves along the pitch circle of the roller.