A rotary table includes a base body, a movable ring rotatably arranged on the base body, a fixed ring arranged on an inner periphery side of the movable ring and fixed to the base body, and a plurality of rolling elements. The rotary table includes a sensor fixed to the base body and a dog fixed to the movable ring. The movable ring has a scale extending at least at a portion of an outer peripheral side surface, and a groove-shaped recess formed to be recessed inward from an outer periphery of the movable ring at a position corresponding to the scale on the outer periphery. The dog has a leg portion fitted to the recess, and a detected portion protruding outward from the leg portion and detectable by the sensor. The leg portion is able to be fixed to the movable ring at any position in the recess.

A rotary table includes a base body, a movable ring rotatably arranged on the base body, a fixed ring arranged on an inner periphery side of the movable ring and fixed to the base body, and a plurality of rolling elements. The rotary table includes a sensor fixed to the base body and a dog fixed to the movable ring. The movable ring has a scale extending at least at a portion of an outer peripheral side surface, and a groove-shaped recess formed to be recessed inward from an outer periphery of the movable ring at a position corresponding to the scale on the outer periphery. The dog has a leg portion fitted to the recess, and a detected portion protruding outward from the leg portion and detectable by the sensor. The leg portion is able to be fixed to the movable ring at any position in the recess.

A machine tool includes a turning position adjustment unit configured to control a turning drive unit so that, when a tool is transferred between a spindle and a grip, if an amount of sway of the tool is greater than or equal to a threshold value, a turret is turned and the amount of sway of the tool becomes less than the threshold value, and an origin point correcting unit configured to correct an origin point in accordance with a turning position of the turret acquired by a turning position acquisition unit, when the turret is turned by the turning drive unit so that the amount of sway of the tool becomes less than the threshold value.

A workpiece holder device for workpieces to be machined on multiple sides, wherein the workpiece can be held axially and radially relative to the first axis between a first workpiece holder, operatively connected to at least one support spindle of the workpiece holder device and rotatable about a first axis, and at least one second workpiece holder, operatively connected to at least one drive spindle of the workpiece holder device and rotatable around the first axis, by force locking by a clamping force which can be built up in the manner of a vice between the first workpiece holder and the second workpiece holder in the axial direction of the first axis and acting on the opposite sides of the workpiece.

A machine tool is equipped with a rotary table, and a clamp mechanism which clamps the rotary table in a manner so that the rotary table does not rotate. A clamping operation by the clamp mechanism is started after a standby time has elapsed from completion of indexing of the rotary table. The machine tool further includes a positional deviation calculating unit adapted to calculate a positional deviation of the rotary table when the clamping operation by the clamp mechanism is completed, and a standby time changing unit adapted to shorten the standby time in the case that an absolute value of the positional deviation is less than a threshold value, and to lengthen the standby time in the case that the absolute value of the positional deviation is greater than the threshold value.

A machine tool is equipped with a rotary table, and a clamp mechanism which clamps the rotary table in a manner so that the rotary table does not rotate. A clamping operation by the clamp mechanism is started after a standby time has elapsed from completion of indexing of the rotary table. The machine tool further includes a positional deviation calculating unit adapted to calculate a positional deviation of the rotary table when the clamping operation by the clamp mechanism is completed, and a standby time changing unit adapted to shorten the standby time in the case that an absolute value of the positional deviation is less than a threshold value, and to lengthen the standby time in the case that the absolute value of the positional deviation is greater than the threshold value.

A rotary table according to the exemplary embodiment of the present disclosure includes a piston 70 having a first tapered portion 72, and a clamp 80 having a second tapered portion 82. When the first tapered portion 72 comes into close contact with the second tapered portion 82 by a movement of the piston 70, a pallet base 30 is fixed to a table base 10, and thus the pallet base 30 is rotated, thereby maintaining a preset posture.

A rotary table according to the exemplary embodiment of the present disclosure includes a piston 70 having a first tapered portion 72, and a clamp 80 having a second tapered portion 82. When the first tapered portion 72 comes into close contact with the second tapered portion 82 by a movement of the piston 70, a pallet base 30 is fixed to a table base 10, and thus the pallet base 30 is rotated, thereby maintaining a preset posture.

A first driving force transmission part is disposed between an attachment part turning transmission shaft and a tool attachment part. The first driving force transmission part transmits rotary driving force from a side of the attachment part turning transmission shaft to the side of the first turning driving force transmission shaft, and includes a groove, a tenon shaped protrusion, and protrusions. The groove is formed on a tip of a slide shaft of the attachment part turning transmission shaft. The tenon shaped protrusion is formed in the first turning driving force transmission shaft and detachably engages with the groove. The protrusions once releases an engaging posture by pressing the groove that is biased to the engaging posture in an disengaging state when the tool is in the middle of the movement to a predetermined position.

In order to provide a tool changer that can detect an entry of a foreign substance into a turret mechanism portion or wear of a turret mechanism part, a tool changer of the present invention includes a reference phase false detection sensing portion that monitors load variations which occur in a turret drive source and detects an entry of a foreign substance into the turret mechanism portion based on a difference between the load variations and a reference load used as a reference. Moreover, the reference phase false detection sensing portion can also detect the progress of wear of the turret mechanism part based on the integral of the absolute value of a difference between the load variations which occur in the turret drive source and the reference load used as a reference.