US 12,129,889 B2
Ball spline having bypass track
Taek Won Lee, Seoul (KR); Hyeok Do Kwon, Seoul (KR); Gi Dong Son, Incheon (KR); Dong Hyup Nam, Siheung-si (KR); William J Fosnight, Windham, NH (US); and Martin R Elliott, Bedford, NH (US)
Assigned to WON ST CO., LTD., Seoul (KR); and WALMART APOLLO, LLC, Bentonville, AR (US)
Appl. No. 17/799,204
Filed by WON ST CO., LTD., Seoul (KR); and WALMART APOLLO, LLC, Bentonville, AR (US)
PCT Filed Feb. 21, 2020, PCT No. PCT/KR2020/002515
§ 371(c)(1), (2) Date Aug. 11, 2022,
PCT Pub. No. WO2021/167137, PCT Pub. Date Aug. 26, 2021.
Claims priority of application No. 10-2020-0019065 (KR), filed on Feb. 17, 2020.
Prior Publication US 2023/0160423 A1, May 25, 2023
Int. Cl. F16C 29/06 (2006.01)
CPC F16C 29/0695 (2013.01) 13 Claims
OG exemplary drawing
 
1. A ball spline with detour tracks, comprising:
a spline shaft;
a nut part surrounding the spline shaft and being movable along a longitudinal direction of the spline shaft; and
a plurality of balls provided between the nut part and the spline shaft,
wherein the nut part comprises:
a nut having a cylindrical hollow body to allow the spline shaft to be inserted thereinto, and
retainers surrounding the spline shaft and being in the form of hollow bodies located on both longitudinal sides of the nut,
the spline shaft comprises one or more tracks concavely extended along the longitudinal direction thereof,
wherein the nut comprises:
one or more load circulating portions having load track grooves concavely formed in a longitudinal direction of the nut on an inner peripheral surface of a hollow portion into which the spline shaft is inserted, and
one or more non-load circulating portions formed in the longitudinal direction of the nut in parallel with the load track grooves,
wherein each of the retainers comprises circulating grooves concaved on an inner peripheral surface thereof while being curved to allow one side to face an end of a respective one of the load track grooves and to allow the other side to face an end of a respective one of the non-load circulating portions so that each one of the circulating grooves connects one of the load track grooves to one of the non-loading circulating portions,
wherein the balls change direction in the circulating grooves of the retainers so that the balls circulate between the load circulating portions and the non-load circulating portions, wherein the balls run between the tracks of the spline shaft and the load track grooves of the load circulating portions, and
wherein each of the tracks of the spline shaft comprises;
a track groove formed in the longitudinal direction of the spline shaft, and
detour tracks including longitudinal sides that are both connected to the track groove.