FEED SCREW DEVICE, LINEAR ACTUATOR AND LIFT DEVICE

PROBLEM TO BE SOLVED: To provide a feed screw device 20 capable of suppressing an increase of a size and a rise of manufacturing cost, even if an uneven contact prevention mechanism of rollers 4 and a screw shaft 1 is mounted. SOLUTION: This feed screw device 20 includes the screw shaft 1 formed with a spiral channel on an outer circumferential surface, the plurality of rollers 4 capable of revolving, while being in contact with the spiral channel, and a cage 2 rotatably supporting the rollers 4 to alternately convert relative rotation and linear motions between the screw shaft 1 and the cage 2. The feed screw device 20 further includes a bearing 5 rotatably supporting the rollers 4 and a holder 6 supporting the bearing 5 and supported by the gage 2. An inner ring of the bearing 5 and the rollers 4 are formed by an integral member. A projection 5d is provided on a side closer to the screw shaft 1 on an outer circumferential surface of an outer ring of the bearing 5, and the holder 6 abuts from a side far from the screw shaft 1 of the projection 5d. Truncated cone shaped rollers 5a of the bearing 5 are arranged with substantially no gaps in a peripheral direction. A screw part 18 for screwing the outer ring of the bearing 5 on the holder 6 is provided to make the bearing 5 and the rollers 4 movable in a rotating shaft direction. COPYRIGHT: (C)2011,JPO&INPIT