US 12,460,680 B2
Tripod type constant velocity universal joint
Taku Itagaki, Shizuoka (JP); Tatsuro Sugiyama, Shizuoka (JP); and Minoru Ishijima, Shizuoka (JP)
Assigned to NTN Corporation, Osaka (JP)
Appl. No. 17/927,119
Filed by NTN Corporation, Osaka (JP)
PCT Filed May 13, 2021, PCT No. PCT/JP2021/018270
§ 371(c)(1), (2) Date Nov. 22, 2022,
PCT Pub. No. WO2021/246129, PCT Pub. Date Dec. 9, 2021.
Claims priority of application No. 2020-095337 (JP), filed on Jun. 1, 2020; and application No. 2021-052157 (JP), filed on Mar. 25, 2021.
Prior Publication US 2023/0204078 A1, Jun. 29, 2023
Int. Cl. F16D 3/205 (2006.01); F16D 3/202 (2006.01)
CPC F16D 3/205 (2013.01) [F16D 3/2055 (2013.01); F16D 2003/2026 (2013.01); Y10S 464/905 (2013.01)] 7 Claims
OG exemplary drawing
 
1. A tripod type constant velocity universal joint, comprising:
an outer joint member having three track grooves each comprising roller guide surfaces arranged so as to be opposed to each other in a circumferential direction of a corresponding one of the track grooves;
a tripod member comprising three leg shafts projecting in a radial direction of the tripod member; and
roller units each comprising a roller and an inner ring configured to support the roller in a freely rotatable manner,
the inner ring of each of the roller units being externally fitted to one of the leg shafts,
the roller units being capable of inclining with respect to the leg shafts, respectively, and
each of the rollers being movable along the roller guide surfaces of one of the track grooves, and being capable of inclining in the one of the track grooves,
wherein an outer peripheral surface of the rollers is formed of a partially spherical surface having a curvature center on an axis of one of the leg shafts,
wherein the roller guide surfaces are each formed of a partially cylindrical surface having a curvature center on a horizontal line passing an intersection of a pitch circle of the track grooves and a center line of one of the track grooves,
wherein the curvature centers of the partially cylindrical surfaces of the roller guide surfaces are located at positions offset from center lines of the track grooves,
wherein under a state in which no torque is applied to the tripod type constant velocity universal joint, an end portion of the outer peripheral surface of at least one of the rollers is held in abutment against the roller guide surfaces of one of the track grooves, and
wherein a contact ratio R/r of a curvature radius R of the partially cylindrical surface of the roller guide surfaces to a curvature radius “r” of the partially spherical surface of the outer peripheral surface of each of the rollers is set to satisfy 0.95≤R/r≤1.08 so that induced thrust of the tripod type constant velocity universal joint is reduced.