Patent ID: 9133921
Filing Date: 2015-09-15
Classification: F16H,Y10T

Abstract:
1. A ball screw having a threaded shaft and a plurality of nuts adjoined to one another and assembled to the threaded shaft, the plurality of nuts being cooled by flowing a coolant through through-holes formed in the plurality of nuts in axial directions of the plurality of nuts, respectively, the ball screw comprising: counterbores of the through-holes formed on opposing end faces of both of adjoining nuts of the plurality of nuts, respectively; and a ring-shaped sealing member having two O-rings and inserted into the counterbores, the two O-rings being fitted on the ring-shaped sealing member from the outside such that the two O-rings are located within the counterbores of the adjoining nuts, respectively; wherein a first depth of a first counterbore of the counterbores is larger than a total length of the sealing member, the first counterbore being formed in one of the adjoining nuts, wherein a second depth of a second counterbore of the counterbores is smaller than the total length of the sealing member, the second counterbore being formed in the other of the adjoining nuts, and wherein circumferential positions of the first counterbore and the second counterbore of the adjoining nuts are arranged to face each other at positions where a desired preload is exerted.