楔式动力卡盘的径向夹持刚度特性研究

在阐明夹持刚度对工件加工精度影响规律的基础上,通过理论、仿真和试验相结合的方法,从卡爪/工件接触状态角度,研究楔式动力卡盘的径向夹持刚度特性。研究卡盘的使用参数,特别是夹紧力、卡爪数量、夹持长度、切削力等对径向夹持刚度的影响规律。针对较大的切削力会使卡盘的径向夹持刚度降低的现象,提出保证高加工精度的极限切削力的判定方法。研究发现:当卡爪和工件在整个夹持长度上完全接触时,卡盘径向夹持刚度的周期性变化不明显;当弯力大于极限值的时候,径向夹持刚度会降低,并重新表现出周期性现象。通过合理配车使夹紧力均匀分布、增大夹紧力和夹持长度是改善卡盘夹持刚度特性、提高极限弯力的有效方法。使用四爪卡盘可以削弱夹持刚度的周期性现象。

Radial Chucking Stiffness Characteristics Analysis of Wedge Type Power Chuck

Based on the clarification of chucking rigidity’s influence on the chucking accuracy, the characteristic of chucking rigidity is researched systematically. Putting the contact state of chucking arc and workpiece, the influence of clamping force, chucking length, and bending force on the radial chucking rigidity is analyzed. The investigation shows that, when the jaw contacts the workpiece along its full clamping length, the variation in apparent radial chucking stiffness with respect to the direction of the bending force can be eliminated. However when the bending force is larger than some critical value, the radial chucking rigidity is reduced, and the variation of that can be observed again. Then the method for improving the characteristic of chucking rigidity and critical bending force is introduced, which combine the enlargement of clamping force and chucking length, turning the top jaw reasonably. Furthermore, a four jaw chuck is effective to be used to eliminate the variation in radial chucking stiffness.