US 12,146,552 B2
Ball screw device and manufacturing method thereof
Yasumi Watanabe, Fujisawa (JP); Ryo Segawa, Fujisawa (JP); and Tomoko Miyamori, Fujisawa (JP)
Assigned to NSK LTD., Tokyo (JP)
Appl. No. 18/265,557
Filed by NSK LTD., Tokyo (JP)
PCT Filed Aug. 3, 2022, PCT No. PCT/JP2022/029813
§ 371(c)(1), (2) Date Jun. 6, 2023,
PCT Pub. No. WO2023/026808, PCT Pub. Date Mar. 2, 2023.
Claims priority of application No. 2021-136411 (JP), filed on Aug. 24, 2021; and application No. 2021-136412 (JP), filed on Aug. 24, 2021.
Prior Publication US 2024/0026959 A1, Jan. 25, 2024
Int. Cl. F16H 25/20 (2006.01); F16H 25/22 (2006.01)
CPC F16H 25/2204 (2013.01) [F16H 25/2015 (2013.01); F16H 2025/204 (2013.01)] 16 Claims
OG exemplary drawing
 
1. A ball screw device, comprising:
a screw shaft having a shaft-side ball screw groove with a spiral shape on an outer peripheral surface and configured to undergo rotational motion during use;
a nut having a nut-side ball screw groove with a spiral shape on an inner peripheral surface and configured to undergo linear motion during use;
balls arranged between the shaft-side ball screw groove and the nut-side ball screw groove;
a fitting cylinder having an end portion on one side in an axial direction that is fitted and fixed to an end portion on an other side in the axial direction of the nut and configured to undergo linear motion together with the nut; and
a retaining ring configured to prevent relative displacement in the axial direction between the nut and the fitting cylinder;
the nut having a first fitting surface provided with a first retaining ring groove on an end portion on the other side in the axial direction;
the fitting cylinder, at an end portion on the one side in the axial direction, having a second fitting surface provided with a second retaining ring groove in a portion facing the first retaining ring groove with regard to a radial direction; and
the retaining ring engaged so as to span between the first retaining ring groove and the second retaining ring groove.