Medical handpiece

摘要

A handpiece for medical treatment having a brushless micromotor mounted in a handpiece casing for driving a cutting tool and having a coolant passageway formed on the outer periphery of a cylindrical yoke fixed to the frame of the handpiece body. In this handpiece, the coolant passageway is formed helically around the axis of the yoke from one end to the other end of the yoke. The sectional area of the yoke in any given longitudinal sectional position along the axis of the yoke is rendered approximately equal to prevent a reduction in motor torque and also enlargement of the handpiece in diameter.