CLAMPING AND UNCLAMPING DEVICE FOR TOOLING SYSTEM OF MACHINE TOOLS USING SHAPE-MEMORY ALLOY ACTUATOR

摘要

The present invention relates to a main shaft device of a machine tool capable of reciprocating a draw bar by a shape-memory alloy actuator, without employing the configuration of a resilient member and a pneumatic or hydraulic cylinder to return the draw bar. The device for clamping and unclamping the main shaft tool of a machine tool according to the present invention includes a spindle rotatably supported by a bearing and a rotor within a spindle housing; a draw bar extending back and forth in the spindle, and installed to reciprocate in a front and back direction within a given distance, the outer diameter of a rear end of the draw bar being widened to form a flared portion having a stepped portion toward the front; a collet chuck connected to the draw bar in the spindle and opened to attach/detach or replace a machine tool when the draw bar moves forward, or retracted to fix the machine tool when the draw bar moves back; and a reciprocation driving unit installed at the spindle to reciprocate the draw bar. The reciprocation driving unit has a memory-shape alloy actuator retracted according to the supply of the power, with a front end being supported by the spindle, and a rear end being supported by the stepped portion of the flared portion, and a heating unit heating the shape-memory alloy actuator to increase the temperature of the shape-memory alloy actuator by a set temperature.