Patent ID: 9729039
Date: 2017-08-08
CPC Classifications: B23Q,H02K

Claim:
1. A machine tool comprising a linear drive unit having a linear motor provided with a magnet and a coil having a coil core, wherein a movable part is configured to linearly move relative to a fixed part via a bearing, wherein the linear drive unit comprises a magnetic gap changing mechanism which is configured to change a magnitude of a magnetic gap between the coil and the magnet, by displacing the coil so that the coil and the magnet approach or are separated from each other, wherein the coil is positioned within a coil bearing, and the coil bearing guides a movement direction of the coil in a direction of the magnetic gap, and wherein the machine tool has a plurality of processing modes in which the magnitudes of the magnetic gaps are different from each other, and the processing modes includes a crude processing mode and a finish processing mode, in which the magnetic gap in the finish processing mode is larger than the magnetic gap in the crude processing mode.