すべり送りねじの流体潤滑摩擦に関する研究 : 第1報, すきま形状モデルの定式化と無限小幅潤滑理論による解析

Because sliding leadscrews used in precision positioning systems are driven by motors directly with higher speed, it becomes necessary to evaluate more accurately their friction losses to estimate the required motor power or heat generation. It has been proved experimentally that the interface between the screw shaft and the nut achieves hydrodynamic condition under higher rotational speed. But the method of calculating the friction has not been established. This study aims at proposing a theoretical formula describing the frictional characteristics of sliding leadscrews under hydrodynamic condition and verify it experimentally. In this report, lead errors of a screw shaft and a nut are measured accurately and discussed to formulate a clearance shape model with respect to the drunkenness error of nut. The infinitely short bearing theory is applied to the shape model so as to derive some dimensionless numbers.