Study on Damping Characteristics of Linear Motion Ball Guide

—Proposal and Verification of Damping Model for Contact between Ball and R Groove—

Abstract

In the previous report, we explained the formulation of dynamic simulation by applying the translational system / rotating system model in vibration theory to the load distribution theory, which is a static analysis method for linear motion ball guides (LMBG). We also conducted an impulse response test to intentionally excite the three-degree-of-freedom mode of LMBG, and reported the contents of verifying the natural frequency of each mode. In this simulation, the spring constant and torsional spring constant with five degrees of freedom, which affect the dynamic rigidity, are calculated by the load distribution theory, so the natural frequency of each mode can be predicted with any model number. However, there is no effective calculation method for the damping ratio that affects the vibration intensity, and after all, it is necessary to perform a test in advance to identify the damping ratio or to assume a value from past measurement results, which is complete. Therefore, this time, we made a two-row experimental LMBG and conducted an impulse response test. By analyzing the correlation between the damping ratio obtained and various cont act parameters derived from Hertz's contact theory, a mathematical expression of the damping ratio, that is, I tried to build a damping model. In addition, we report the contents of applying this model to the dynamic simulation of LMBG and verifying it with an actual product.