Provided is a lathe capable of facilitating replacement of a ball screw. A machine tool comprises a base, a moving unit, a ball screw, a cap, and a supporting unit provided on the base to support the cap. The cap has a body and a flange expanded larger than the body on the outer side thereof with respect to the axis direction. The supporting unit comprises a recess part which receives the body. The recess part is provided with an opening allowing the threaded shaft to pass in a direction perpendicular to the axis direction in the state that the supporting unit is provided on the base. The supporting unit further comprises a positioning part on which an inner surface of the flange abuts in the axis direction in the state that the body is received in the recess part.

Provided is a lathe capable of facilitating replacement of a ball screw. A machine tool comprises a base, a moving unit, a ball screw, a cap, and a supporting unit provided on the base to support the cap. The cap has a body and a flange expanded larger than the body on the outer side thereof with respect to the axis direction. The supporting unit comprises a recess part which receives the body. The recess part is provided with an opening allowing the threaded shaft to pass in a direction perpendicular to the axis direction in the state that the supporting unit is provided on the base. The supporting unit further comprises a positioning part on which an inner surface of the flange abuts in the the axis direction in the state that the body is received in the recess part.

A high-speed nut rotation feed ball screw device includes a ball screw, a ball screw nut, a bearing unit, and a driving unit. The ball screw is fixed on a machine tool via a ball screw seat. The bearing unit includes an inner bearing fixing sleeve, an outer bearing fixing sleeve, and a bearing assembly. One end of the inner bearing fixing sleeve is fixedly connected to one end of the ball screw nut, and another end is fixedly connected to the driving unit. The ball screw nut is arranged on the ball screw. The driving unit includes a first pulley, a second pulley, a synchronous belt, and a driving motor. The first pulley is connected to the driving motor. The second pulley is sleeved on the ball screw and is connected to the inner bearing fixing sleeve. The first and second pulleys are connected via the synchronous belt.