Title:
BALL SCREW DEVICE AND ELECTRIC POWER STEERING DEVICE
Document Type and Number:
WIPO Patent Application WO/2018/147229
Kind Code:
A1
Abstract:
A ball screw device according to the present invention includes a screw shaft, a nut, a plurality of balls, and an end deflector. The screw shaft has a first screw groove in the outer circumferential surface. The nut includes a second screw groove provided in the inner circumferential surface, a cut-away portion provided in an end face, and a return hole provided in the bottom surface of the cut-away portion, which is perpendicular to the shaft direction of the screw shaft, so as to penetrate in the shaft direction. The plurality of balls roll between the first screw groove and the second screw groove. The end deflector fits in the cut-away portion. The nut has a curved section in the side surface of the cut-away portion, at a position between the second screw groove and the return hole. In a first section of the nut taken along a plane perpendicular to the shaft direction and passing through the second screw groove and the cut-away portion, the curved section includes an arc section centered at a point located on the outer side of the second screw groove in the radial direction centered at the rotation shaft of the nut.
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Inventors:
YOROZU YUSUKE (JP)
Application Number:
PCT/JP2018/003820
Publication Date:
August 16, 2018
Filing Date:
February 05, 2018
Export Citation:
Assignee:
NSK LTD (JP)
International Classes:
F16H25/22; B62D5/04; F16H25/24
Foreign References:
| JP2014077459A | 2014-05-01 | |||
| JP2017002978A | 2017-01-05 | |||
| JP2013024321A | 2013-02-04 | |||
| JP2004036644A | 2004-02-05 |
Other References:
See also references of EP 3399213A4
Attorney, Agent or Firm:
SAKAI INTERNATIONAL PATENT OFFICE (JP)
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