US 12,241,527 B2
Multi-row ball screw
Takayuki Yabe, Kanagawa (JP)
Assigned to NSK LTD., Tokyo (JP)
Appl. No. 18/285,049
Filed by NSK LTD., Tokyo (JP)
PCT Filed Mar. 23, 2022, PCT No. PCT/JP2022/013763
§ 371(c)(1), (2) Date Sep. 29, 2023,
PCT Pub. No. WO2022/210223, PCT Pub. Date Oct. 6, 2022.
Claims priority of application No. 2021-062357 (JP), filed on Mar. 31, 2021.
Prior Publication US 2024/0191789 A1, Jun. 13, 2024
Int. Cl. F16H 25/22 (2006.01); F16H 25/24 (2006.01)
CPC F16H 25/24 (2013.01) [F16H 25/2204 (2013.01)] 3 Claims
OG exemplary drawing
 
1. A multi-row ball screw comprising:
a nut having a plurality of spiral grooves on an inner peripheral surface thereof;
a screw shaft having a plurality of spiral grooves on an outer peripheral surface thereof; and
a plurality of balls disposed so as to be rollable on rolling paths constituted by the plurality of spiral grooves of the nut and the plurality of spiral grooves of the screw shaft,
wherein each of the plurality of spiral grooves of the nut includes a U-shaped first spiral groove portion having left and right flanks that are respectively configured to come into contact with two-row balls and separated from each other in an axial direction, and two second spiral grooves portion continuous with each row of the first spiral groove portion and each having left and right flanks that are configured to come into two-point contact with one ball of the plurality of balls.