Title:
BALL SCREW DEVICE AND ELECTRIC POWER STEERING DEVICE
Document Type and Number:
Japanese Patent JP2022135011
Kind Code:
A
Abstract:
To provide a ball screw device which is excellent in durability.SOLUTION: A ball screw device comprises a nut, a screw shaft and a plurality of balls. An outside raceway surface is provided at the nut. An inside raceway surface is provided at the screw shaft. The inside raceway surface is longer than the outside raceway surface in a length in an axial direction parallel with a center axis of the screw shaft. The inside raceway surface has a neutral raceway surface located in a center part in the axial direction, a first raceway surface arranged in a first direction rather than the neutral raceway surface, and a second raceway surface arranged in a second direction rather than the neutral raceway surface. A lead of the outside raceway surface is equal to a lead of the neutral raceway surface. A lead of the first raceway surface and a lead of the second raceway surface are at least partially larger than the lead of the outside raceway surface. The plurality of balls have clearances in the axial direction when arranged between the outside raceway surface and the neutral raceway surface. The plurality of balls are imparted with preloads when arranged between the outside raceway surface and the first raceway surface, and between the outside raceway surface and the second raceway surface.SELECTED DRAWING: Figure 3
Inventors:
NAGAI YUTAKA
Application Number:
JP2021034566A
Publication Date:
September 15, 2022
Filing Date:
March 04, 2021
Export Citation:
Assignee:
NSK LTD
International Classes:
F16H25/22; B62D5/04; F16H19/04; F16H25/20
Attorney, Agent or Firm:
Sakai International Patent Office
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