Voice coil-type linear motor with cooling function

Abstract

A voice coil type linear motor with a cooling function. A closed magnetic circuit formed into the θ-shape, by an inner yoke provided between a pair of outer yokes made up of magnetic materials arranged in parallel with a longitudinal center axis in such a manner as to be in parallel with the pair of outer yokes. The outer yokes and side yokes are provided at both end portions of the inner yoke. Permanent magnets are provided on inner sides of the outer yokes and on outer sides of the inner yoke with polarities thereof which face opposite surfaces of the outer yoke. The inner yoke is made opposite to each other or with polarities thereof which face only the outer yokes being made opposite each other to thereby a field. An armature made up of a bobbin of non-magnetic and insulating materials is provided. A coil is provided around the bobbin between the permanent magnets via air gaps in such a manner as to move in an axial direction or in such a manner that. The coil is wound around the bobbin. A case is constructed on an exterior of the bobbin. A coil portion is made watertight. A fluid supply port and a fluid discharge port are provided on the bobbin or the case. A cooling fluid is caused to flow between the coil and the case so that the coil is cooled directly.