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.

公开(公告)号：US20230349453A1

公开(公告)日：2023-11-02

申请号：US18026463

申请日：2021-10-20

Applicant: NSK LTD.

Inventor： Reona UMEI ,  Yasumi WATANABE ,  Yuji SHIMOMURA

IPC: F16H25/22 ,  F16H25/20 ,  F16H25/24

CPC classification number: F16H25/2204 ,  F16H25/2015 ,  F16H25/24 ,  B60T13/745 ,  F16H2025/2081

Abstract: A linear motion actuator has a ball screw device having a screw shaft, a nut, and a plurality of balls, a piston mounted on one end of the screw shaft, and a stroke limiting mechanism setting an operation starting point in time of the screw shaft toward a first direction pointed by the one end. The nut has one end face directed to the first direction and a protruding part protruding from the one end face.

公开(公告)号：US20180347675A1

公开(公告)日：2018-12-06

申请号：US15562315

申请日：2016-02-24

Applicant: NSK LTD.

Inventor： Hiroshi KAWAHARA ,  Hiroyasu YOSHIOKA ,  Tetsu TAKEHARA ,  Yuji SHIMOMURA

IPC: F16H13/08 ,  F16H13/14

CPC classification number: F16H13/08 ,  F16H13/04 ,  F16H13/14

Abstract: A friction roller-type reduction gear includes a sun roller arranged concentrically with an input shaft, a ring roller having a stationary ring roller element and a moveable ring roller element, a plurality of intermediate rollers configured to be in rolling contact with an outer peripheral surface of the sun roller and an inner peripheral surface of the ring roller, a coupling part configured to couple the ring roller and the output shaft, and a loading cam mechanism having a cam ring and configured to change a contact surface pressure of each rolling contact surface. The outer peripheral surface of the sun roller is a concave curved surface of which a shape of an outer edge in an axial cross-section is a single circular arc-shaped concave curve, and an outer peripheral surface of the intermediate roller is a convex curved surface of which a shape of an outer edge in an axial cross-section is a single circular arc-shaped convex curve.