ELECTRICAL DISCHARGE MACHINE AND METHOD FOR MANUFACTURING MACHINED OBJECT USING THE SAME

摘要

In an electrical discharge machine that applies a voltage between an electrode and a workpiece to generate electrical discharge, an electrode holder holds the electrode. An ultrasonic motor has a fingertip that comes into contact with electrode holder, and moves electrode holder in a driving direction by moving the fingertip in an annular manner at an ultrasonic-range frequency. A roller bearing guides the movement of the electrode holder in the driving direction. A control circuit controls a position of the electrode in the driving direction by driving the ultrasonic motor, and moves the electrode holder based on an abnormality occurring in resistance against the movement of the electrode holder in the driving direction such that the electrode holder is moved by a movement distance equivalent to when the largest roller element among a plurality of roller elements of the roller bearing rolls and rotates once without sliding or longer.

主权项

1. An electrical discharge machine for applying a voltage between an electrode and a workpiece to generate electrical discharge such that the workpiece is melted by the electrical discharge and machined, the electrical discharge machine comprising:
an electrode holder that holds the electrode; an ultrasonic motor that has a fingertip that comes into contact with the electrode holder, and moves the electrode holder in a predetermined driving direction by moving the fingertip in an annular manner at an ultrasonic-range frequency; a roller bearing that guides the movement of the electrode holder in the driving direction, the roller bearing comprising:
movement blocks that are fixed to the electrode holder;a rail that supports the movement blocks and guides movement of the movement blocks; anda plurality of roller elements that are interposed between the movement blocks and the rail; and a control circuit that controls a position of the electrode in the driving direction by driving the ultrasonic motor, the control circuit being configured to move the electrode holder based on an abnormality occurring in resistance against the movement of the electrode holder in the driving direction, the electrode holder being moved by a movement distance equivalent to when the largest roller element among the plurality of roller elements rolls and rotates once without sliding or longer.