Abstract
This paper deals with the load distribution and the guiding accuracy of x-table assembled with two cross roller guide units applied for electric spark machine, semi-conductor manufacturing machine, etc. The load distribution formula is derived under the application of vertical and horizontal external load, pitching, rolling and yawing moments. Both theoretical and experimental results are discussed under various load eccentricities. The followings are the reached conclusions. (1) Even if only a vertical load is applied on the midpoint of x-table, the distribution loads on each roller are considerably become one side contact situation at both stroke end positions of the x-table, due to the mechanical motions in accordance with the movements of x-table and cross roller cages. (2) To give a moderate preloading under the large load eccentricity condition for the cross roller guides is effective against the load distribution, rigidity and guiding accuracy. (3) It is made clear that the theoretical results are agreed with the experimental ones, those are the calculated values from the measuring ones by means of six electric micrometer sensors setting up for the two straight edges aligned with the x-table, that is the vertical and horizontal displacement, pitching, rolling and yawing angle, respectively.
