Chucking device and chucking method for machine tool

摘要

In a chucking device and a chucking method for a machine tool which grip a workpiece that serves as a target object to be processed by the machine tool, a first cylinder and a second cylinder are controlled based on the position of a piston of the first cylinder detected by a length measuring sensor, and the position of a piston of the second cylinder detected by a length measuring sensor. In this manner, the workpiece is gripped by respective gripping members at a predetermined position, i.e., the axial center, of a chuck main body.

主权项

1. A chucking device for a machine tool for gripping a workpiece as a target object to be processed by the machine tool, comprising:
a chuck main body; a first cylinder attached to the chuck main body and in which a first piston rod connected to a first piston is displaced in a direction toward the workpiece to thereby position the workpiece; a second cylinder attached to the chuck main body and in which a second piston rod connected to a second piston is displaced in a direction toward the workpiece to thereby press the positioned workpiece; a first position detecting sensor that detects a position of the first piston; a second position detecting sensor that detects a position of the second piston; a control mechanism that controls the first cylinder and the second cylinder based on the position of the first piston and the position of the second piston, which have been detected, such that the workpiece is gripped at a predetermined position of the chuck main body by the first piston rod and the second piston rod; a first cylinder controller that displaces the first piston rod by controlling the first cylinder; a second cylinder controller that displaces the second piston rod by controlling the second cylinder; and an end position calculating unit, which calculates a position of an end of the first piston rod based on the detected position of the first piston, and calculates a position of an end of the second piston rod based on the detected position of the second piston, wherein: the first piston rod is displaced toward an axial center of the chuck main body in accordance with a control performed by the first cylinder controller to thereby position the workpiece at a predetermined position on the chuck main body; the second piston rod is displaced toward the axial center of the chuck main body in accordance with a control performed by the second cylinder controller to thereby press the workpiece; the first cylinder controller displaces the first piston rod toward the axial center, until the calculated position of the end of the first piston rod reaches a first position configured to position the workpiece; and the second cylinder controller displaces the second piston rod toward the axial center, until the calculated position of the end of the second piston rod reaches a second position configured to press the workpiece.