US 2013/0220047 A1 · Ball Screw

Abstract

A ball screw having a groove-shaped ball return passage has improved durability, ball circulation performance, and working performance. The ball screw is provided with: a threaded shaft having a spiral groove at its outer circumferential surface; a nut having a spiral groove which faces the spiral groove at its inner circumferential surface; a plurality of balls rotatably loaded in a spiral raceway constituted by the two spiral grooves; and a ball circulation groove which returns and circulates the balls from an end point to a start point of the raceway. Further, the edge portions constituted by the two side surfaces of the ball circulation groove and the surfaces which continue from the side surfaces and extend in the axial direction are formed to be rounded.

Claims27

Dependent claims

(canceled)

A ball screw comprising:

a threaded shaft having a spiral threaded groove at an outer circumferential surface;
a nut having a threaded groove which faces the threaded groove of the threaded shaft at an inner circumferential surface;
a plurality of balls rotatably loaded in a spiral ball raceway constituted by both of the threaded grooves;
and
a ball circulation groove which returns and circulates the balls from an end point to a start point of the ball raceway,
wherein the nut is formed by concaving a part of the inner circumferential surface of the nut to form the ball circulation groove constituted by a concaved groove, and forming the threaded groove in the inner circumferential surface of the nut to be connected with an end part of the ball circulation groove, and
wherein at least a part of a edge portion constituted by both of side surfaces of the ball circulation groove and a surface which continue from each of the side surfaces and which extend in an axial direction is formed to be rounded.

4 more elements

Dependencies are inferred from the claim text.

Facts

Application

13/879,752Filed 31 Mar 2011

Priority

JP 2010-25539015 Nov 2010

Published

29 Aug 2013

Term ends

Not estimatedThe source records don’t support an estimate.

Classification5 codes

F16H 25/2214
With balls: with elements for guiding the circulating balls
F16H 25/2223
With elements for guiding the circulating balls: cross over deflectors between adjacent thread turns, e.g. S-form deflectors connecting…
Y10T 74/19772
Return path geometry: rolling element deflector
F16H
Gearing

Ball Screw

Life of this patent

Ball Screw

Life of this patent

Abstract

Claims27