Fixing device for workpiece in machine tool and machine tool having the fixing device

A fixing device of a workpiece in a machine tool comprising:

• a fixing section configured to rotate with a main spindle, fix the workpiece in a closed state, and release the fixation of the workpiece in an open state;
• an actuating lever configured to rotate with the main spindle, and be disposed to open and close the fixing section;
• a sliding member which is provided to be movable between a first position and a second position along an axis direction of the main spindle, and configured to rotate with the actuating lever while displacing the actuating lever in contact with the actuating lever in the second position in the movable range;
• and
• a rotation transfer member which is disposed to have contact with the sliding member in the first position in the movable range of the sliding member, and configured to rotate with the main spindle, wherein
• the sliding member loosely engages with the main spindle in a rotatable manner, and rotates with the rotation transfer member when the sliding member has contact with the rotation transfer member in the first position of the movable range of the sliding member, and
• the movable range of the sliding member has a range where the sliding member does not have contact with either the rotation transfer member nor the actuating lever such that a part of the sliding member that has contact with the actuating lever changes according to the rotation of the sliding member relative to the main spindle when the sliding member has contact with the actuating lever.