Linear motor device for machine tool

Abstract

A linear motor device includes a primary linear motor member and a secondary linear motor member shaped of teeth of a comb with a plurality of projecting portions arranged at predetermined intervals. Recesses defined between the projecting portions are filled up with filler members for flattening a surface of the secondary linear motor member facing the primary linear motor member. Therefore, it is possible to remove chips from the surface easily. Since the filler members are made of low magnetical permeability material, the magnetic shielding between the neighboring projecting portion can be maintained. A linear motor device for a machine tool includes a bar type secondary linear motor member having both ends supported by an immovable member of the machine tool and a cylindrical primary linear motor member attached to a movable member of the machine tool. The secondary linear motor member is inserted into the primary linear motor member through a clearance so that the primary linear motor member can move in the axial direction of the secondary linear motor member. The primary linear motor member has cylindrical primary electrical wirings surrounding the whole periphery of the secondary linear motor member. An attractive force between the primary and secondary linear motor members acts over a whole periphery of the secondary linear motor member uniformly. Therefore, the resulting radial forces onto the secondary linear motor members are canceled each other.