Modeling and Experiment on Contact Stiffness and Accuracy Analysis of Ball Linear Guide Feed Unit

The contact stiffness and the error analysis have an important effect on the manufacture and the optimization of Ball Linear Guide Feed Unit( BLGFU). In order to analyze the contact stiffness and linear errors or angle errors of BLGFU,in this paper,the contact stress and deformation mechanics between the ball and rail is analyzed. Based on Hertz theory of contact and theory of the multi-body system,a model of the contact stiffness considering the changes in contact angle is established. With the increasing of the external load,the varying trend of the contact deformation can be obtained. Therefore, the motion accuracy degradation of the BLGFU can be analyzed. By using a special experimental device and test system of the rolling linear guide worktable,the horizontal contact stiffness and the vertical linear stiffness are obtained,respectively. By comparing the contact stiffness of the experiment dates and the simulation results,the variation tendency of two curves is consisted and the difference between the measured values and the theoretical values is less than 18%. It is obvious that the model of the contact stiffness considering changes of contact angle has accuracy and feasibility. Thus,while external force point locating at different positions; the contact stiffness and the accuracy analysis of the BLGFU are proved validity by simulations.