| 摘要 |
PROBLEM TO BE SOLVED: To provide a ball screw device which is reduced in cost by reducing its size and the number part items.SOLUTION: A ball screw device 1 comprises a ball screw 4 which is arranged at one end of a motor shaft 3, and rolling bearings 7, 8 which rotatably pivot the motor shaft 3 and a nut 6 with respect to a housing 5. The ball screw 4 comprises: a screw shaft 9 in which a spiral screw groove 9a is formed at an external peripheral face; the nut 6 in which a spiral screw groove 6a is formed at an internal peripheral face; balls 11 accommodated in both the opposing screw grooves; and end plates 17, 18. The ball screw device also comprises a rotor 2b which is attached to the motor shaft 3, arranged at the screw shaft 9 coaxially therewith, and rotates integrally with the nut 6, and a stator 2a which is attached to the housing 5. The nut 6 of the ball screw 4 is formed at the motor shaft 3 integrally therewith, an inside rolling face 8a of the rolling bearing 8 is directly formed at an external periphery of the nut 6, and a center of the inside rolling face 8a in an axial direction is arranged in a center of the whole width of the nut 6.SELECTED DRAWING: Figure 1 |
