精密鼓形ウォームギヤの製作 ウォーム研削装置の試作

Abstract

High accurate worm gears can be effectively used as an angle dividing standard. Wildhaber worm gearing is a kind of hourglass worm gearing. Due to the geometrical simplicity, its worm and worm wheel can be easily finished and accurately measured. This study describes a precision grinding method of the Wildhaber worm. Hobbing machine can cut the hourglass worms, but cannot give them higher accuracy than its master worm gears. To overcome this limitation, a special grinding device is made. The features of this grinding device are as follows : the linear motion of ball screw gives a grinding spindle very accurate circular feed, and this device has no mechanical connection between that circular feed and the rotation of the workpiece. In the first place, the working accuracy of the device was measured. The rotational accuracy of the rotary table relative to the worm was 1 second of arc. The accuracy of the ground worm using this device was 1.5 second of arc.