公开(公告)号：US20230015290A1

公开(公告)日：2023-01-19

申请号：US17785349

申请日：2021-03-12

Applicant: NSK Ltd.

Inventor： Kazuya YAMADA ,  Yuji SHIMOMURA ,  Yasuaki ABE ,  Kanta SATO

IPC: F16H25/22

Abstract: A ball screw device has a screw shaft; a nut; a circulation part; and balls; a housing concave groove provided on the outer circumferential surface of the nut and linearly extending in the axial direction and opening to end surfaces on both outer sides in the axial direction of the nut, a circulation part arranged inside the housing concave groove, and the circulation part being prevented from displacing toward the outer side in the radial direction and displacing in the circumferential direction with respect to the nut by engaging an engaging convex portion of a fixing portion provided in the end portion on each of both outer sides in the axial direction of the circulation part with an engaging recess portion provided in the end portion of each of both outer sides in the axial direction of the housing concave groove.

公开(公告)号：US20230087898A1

公开(公告)日：2023-03-23

申请号：US17439254

申请日：2021-03-10

Applicant: NSK LTD.

Inventor： Kazuya YAMADA ,  Yuji SHIMOMURA ,  Kanta SATO ,  Yasuaki ABE

IPC: F16H25/22

Abstract: In the ball screw device, the circulation path that returns balls from the end point to the start point of the load path includes a return path, scooping paths, and connecting paths. The scooping path has an arc-shaped center line that is curved outward in the radial direction as going toward the reference imaginary flat plane including the center axis of the screw shaft and the center line of the return path in the circumferential direction. The connecting path is arranged on the reference imaginary flat plane and includes a straight path having a linear center line extending in a direction orthogonal to the center axis of the screw shaft. When the radius of curvature of the center line of the scooping path is R1, the scooping angle is θ, and the entire length of the straight path is S, R1 cos(90°−θ)+S is made larger than the diameter of the balls.