BALL SCREW DEVICE

To provide a ball screw device capable of preventing slip-off while reducing labor and preventing an increase in the number of components.SOLUTION: A ball screw device is equipped with a screw shaft that has a first end portion pointing in a first direction, a second end portion pointing in a second direction, and a screw portion provided between the first end portion and the second end portion, a nut that is inserted in the screw shaft, a plurality of balls disposed between the screw portion and the nut, a first bearing that rotatably supports the first end portion, and a second bearing that rotatably supports the second end portion. At a body portion of the nut, a circulation path for circulating the balls is provided. The first end portion, the second end portion, and the screw portion are integrated. The first end portion is provided with an inner peripheral raceway groove on an outer peripheral surface, and forms an inner ring portion of the first bearing. An outer diameter of the first end portion is smaller than a root diameter of the screw portion.SELECTED DRAWING: Figure 1 【課題】労力の削減と部品点数の増加防止を図りつつ、バレ防止を達成できるボールねじ装置を提供する。【解決手段】ボールねじ装置は、第１方向を指す第１端部と、第２方向を指す第２端部と、第１端部と第２端部との間に設けられたねじ部と、を有するねじ軸と、ねじ軸に貫通されるナットと、ねじ部とナットとの間に配置された複数のボールと、第１端部を回転自在に支持する第１軸受と、第２端部を回転自在に支持する第２軸受と、を備え、ナットの本体部には、ボールを循環させるための循環路が設けられ、第１端部と第２端部とねじ部とは、一体であり、第１端部は、外周面に内周軌道溝が設けられ、第１軸受の内輪部を成し、第１端部の外径は、ねじ部の谷径よりも小さい。【選択図】図１