Title:
MULTI-STAGE BALL SCREW UNIT AND ELECTRIC ACTUATOR USING SAME
Document Type and Number:
WIPO Patent Application WO/2021/210406
Kind Code:
A1
Abstract:
Provided are a multi-stage ball screw unit that can reduce the size of the entire device while sufficiently increasing the load capacity of an axial load, and an actuator using the screw unit, the multi-stage ball screw unit comprising: a first screw shaft (3) in which a first spiral groove (30) on which a rolling element rolls is formed on the outer peripheral surface and a first spline groove is formed along the axial direction; a second screw shaft (4) which is formed in a hollow cylindrical shape covering the first screw shaft (3) from the outside and in which a second spiral groove (40) on which the rolling element rolls is formed in the opposite direction to the first spiral groove (30) on the outer peripheral surface and a second spline groove is formed along the axial direction; an inner screw nut (5) that is provided in the hollow portion of the second screw shaft (4) and screwed into the first spiral groove (30) of the first screw shaft (3) with a large number of balls being interposed therebetween; and an outer ball screw nut (6) screwed into the second spiral groove (40) of the second screw shaft (4) with a large number of balls being interposed therebetween, wherein the number of rows of the first spiral groove (30) is set to be larger than the number of rows of the second spiral groove (40).
Inventors:
SAKUYAMA TAKASHI
OSHIDA TAKASHI
NISHIDE TETSUHIRO
OSHIDA TAKASHI
NISHIDE TETSUHIRO
Application Number:
PCT/JP2021/013997
Publication Date:
October 21, 2021
Filing Date:
March 31, 2021
Export Citation:
Assignee:
THK CO LTD (JP)
International Classes:
H02K7/06; F16H25/20; F16H25/22
Foreign References:
| JPH03213753A | 1991-09-19 | |||
| US20170266385A1 | 2017-09-21 | |||
| US20130017929A1 | 2013-01-17 |
Attorney, Agent or Firm:
IDE Tetsuroh (JP)
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