Patent ID: 8375815

Claim:
A rolling-element screw device, comprising: a large number of rolling elements; a screw shaft having an outer periphery on which a rolling groove for the large number of rolling elements is helically formed; a nut member which has a through-hole through which the screw shaft is passed and which is threadedly engaged with the screw shaft through intermediation of the large number of rolling elements; a lubricant supply hole formed through the nut member between an outer peripheral surface of the nut member and an inner peripheral surface of the nut member; a lubricant tank mounted to the outer peripheral surface of the nut member and comprising an accommodating chamber for lubricant; a lubricant applying body standing from the lubricant tank, and inserted into the lubricant supply hole along with a mounting operation of the lubricant tank with respect to the nut member, the lubricant applying body having a leading end portion coming into contact with the rolling groove the screw shaft so as to apply the lubricant; and a cover plate fixed to the outer peripheral surface of the nut member and comprising a tank mounting hole for positioning the lubricant tank, wherein the lubricant tank comprises a positioning leg portion to be fitted into the tank mounting hole, and wherein the lubricant applying body stands from the lubricant tank along an insertion direction of the positioning leg portion with respect to the tank mounting hole.