Linear Motion Ball Guides Kinetic Analysis Of The Contact Problem

With the characteristics of low coefficient of friction, high precision, low noise, highload capacity, linear motion ball guide has been widely used in the high-end CNC machinetools, so its dynamic characteristics has been more concerned by companies, and itsquality requirements has been higher by people. Vibration and noise is the key factor tomeasure the quality of linear motion ball, and vibration will directly lower the precision oflinear motion ball. This paper will focus on the study from the vibration characteristics oflinear motion ball.Firstly, the kinematics characteristics of the ball in the race is analyzed, and thecomposite movement of ball is decomposed, and the characteristics of each movementgesture is analyzed, and the expression is deduced. With the analyze of the movementgesture, the influence factors of the accuracy of ball movement has get.Secondly, the contact state between the ball and race in bearing region is analyzed. Inthe analysis, the surface waviness of race has been considered, and the race waviness ofresearch guide has been tested. On this basis, the model of waviness is established, and theanalytical model of contact changes between the ball and the raceway due to surfacewaviness is established. Based on the Hertz contact theory, the relationship between thecontact amount and contact force between the ball and the race was studied. The sliderwas simplified as a rigid body, and the dynamic equations of slider were established. Thedynamic equation is solved by using Runge-Kutta numerical method in matlab, and thevibration of the slider on five degrees is get, and the influence on the dynamiccharacteristics of linear motion ball guide caused by the surface waviness is analyzed.At last, in the vibration test, the slider is at a particular speed on the rail by thepulling of the workbench, and the displacement signal of the slider in the non-movementdirection is collected by displacement sensor, After the comparison with the simulationresults, both results agree well, and the validity of the dynamic model is verified.