According to an embodiment of the present invention, a torque variation of a servomotor, which is measured in a numerical control apparatus of an existing numerical control machine tool, is observed, and a backlash is detected by calculating a transfer distance of an output shaft of the servomotor at a torque peak, without adding additional positioning detection equipment, thereby detecting an accurate backlash amount without adding additional equipment.

A rotary table device is provided, which includes a housing having a space portion formed therein, a main shaft installed in the space portion and provided with a worm wheel coupled along an outer circumference thereof, a pair of worm shafts provided to be engaged with the worm wheel at both sides of the worm wheel in a predetermined position of the space portion, a driving motor installed on one side of the housing, a power transmission member installed on an upper surface of the housing to transmit a driving force of the driving motor to the pair of worm shafts, and a clearance adjustment member installed in a predetermined position of each lower end of both sides of the housing.

A rotary table device is provided, which includes a housing having a space portion formed therein, a main shaft installed in the space portion and provided with a worm wheel coupled along an outer circumference thereof, a pair of worm shafts provided to be engaged with the worm wheel at both sides of the worm wheel in a predetermined position of the space portion, a driving motor installed on one side of the housing, a power transmission member installed on an upper surface of the housing to transmit a driving force of the driving motor to the pair of worm shafts, and a clearance adjustment member installed in a predetermined position of each lower end of both sides of the housing.

A counterweight mechanism for a swivel arrangement includes first and second counterweights each including a seat, an axle, and two cylinders. The swivel arrangement has one end adjacent to the axle. The axle is rotatably, partially disposed in the seat. Each cylinder has a first end pivotably secured to a position proximate to the axle and a second end pivotably secured to the seat.

A counterweight mechanism for a swivel arrangement includes first and second counterweights each including a seat, an axle, and two cylinders. The swivel arrangement has one end adjacent to the axle. The axle is rotatably, partially disposed in the seat. Each cylinder has a first end pivotably secured to a position proximate to the axle and a second end pivotably secured to the seat.

A drive device for a movement unit of a machine tool includes a first toothed element driven by a drive motor and provided as a drive pinion including a first tooth arrangement and a second toothed element provided as a toothed rack including a second tooth arrangement. One of the first and second toothed elements is connected to a machine frame, and the other of the first and second toothed elements is connected to the movement unit. The first and second toothed elements are moved relative to each other along a movement axis of the first and second toothed elements by the drive motor via a meshing between the first and second tooth arrangements and via an engagement between the first and second tooth arrangements along an engagement axis that extends perpendicularly to the movement axis.

A drive device for a movement unit of a machine tool includes a first toothed element driven by a drive motor and provided as a drive pinion including a first tooth arrangement and a second toothed element provided as a toothed rack including a second tooth arrangement. One of the first and second toothed elements is connected to a machine frame, and the other of the first and second toothed elements is connected to the movement unit. The first and second toothed elements are moved relative to each other along a movement axis of the first and second toothed elements by the drive motor via a meshing between the first and second tooth arrangements and via an engagement between the first and second tooth arrangements along an engagement axis that extends perpendicularly to the movement axis.