| 摘要 |
A machine tool having movable axes driven by linear motors has a brake unit disposed in parallel with each linear motor. When the linear motors are not excited, the brake units are turned on to lock the movable axes. When the linear motors are excited, if a machining signal is off, indicating that machining is not in progress, and no manual command is issued, the brake units are likewise turned on to lock the movable axes. The brake units have a certain amount of play so that even when locked, a movable axis can move by a certain amount to enable the linear motor, if excited, to halt in a stable position, avoiding overcurrent flow.
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