Nsk Corporation

Seiji Higuchi

Nobuo Goto

Hiroyuki Itoh

Takashi Imanishi

Makoto Fujinami

Hiroshi Kato

Nobuaki Mitamura

Hiroshi Fukushima

Norihisa Kobayashi

Masami Tanaka

Kouji Ishikawa

Masayoshi Shimizuya

In a toroidal-type continuously variable transmission, a plurality of trunnions is respectively swingable about a pair of mutually concentric pivot shafts through a plurality of radial needle roller bearings respectively supporting the pivot shafts. Each of the radial needle roller bearings includes: an outer race interposed between an outer peripheral surface of the pivot shaft and an inner peripheral surface of the circular hole of the support plate, the outer race having an outer peripheral surface formed in a spherically convex surface; and a plurality of needle rollers respectively disposed on the inside diameter side of the outer race. The outer race is formed with an inwardly facing flange portion on the inner peripheral surface of the end portion thereof.

Toroidal-type continuously variable transmission

A toroidal type continuously variable transmission, includes: at least one pair of disks concentrically disposed on each other and rotatably supported independent from each other; a trunnion swingable about a pivot shaft; a displacement shaft including a support shaft portion and a pivot shaft portion that are parallel and eccentric to each other, the support shaft portion rotatably supported to the circular hole of the trunnion through a radial bearing, the pivot shaft portion being protruded from an inner surface of the middle portion of the trunnion; a power roller nipped between the concave surfaces of the pair of disks while being rotatably supported on an outer circumferential surface of the pivot shaft portion; and a thrust bearings located between the power roller and the inner surface of the middle portion of the trunnions. An eccentric quantity of the displacement shaft being a distance between the support shaft portion and the pivot shaft portion is within a range from 5 mm to 15 mm.

Toroidal type continuously variable transmission

A toroidal type continuously variable transmission, includes: at least one pair of disks concentrically disposed on each other and rotatably supported independent from each other; a trunnion swingable about a pivot shaft; a displacement shaft including a support shaft portion and a pivot shaft portion that are parallel and eccentric to each other, the support shaft portion rotatably supported to the circular hole of the trunnion through a radial bearing, the pivot shaft portion being protruded from an inner surface of the middle portion of said trunnion; a power roller nipped between the concave surfaces of the pair of disks while being rotatably supported on an outer circumferential surface of the pivot shaft portion; and a thrust bearings located between the power roller and the inner surface of the middle portion of the trunnions. An eccentric quantity of the displacement shaft being a distance between the support shaft portion and the pivot shaft portion is within a range from 5 mm to 15 mm.

In the toroidal-type continuously variable transmission, the radial needle roller bearing includes a plurality of needle rollers, the two end portions of each of the needle rollers in the axial direction thereof are crowned, and the crowning amount is set such that, in the portion of the needle roller that is situated by 7-13% of the axial-direction length toward the axial-direction central portion of the needle roller from the axial-direction end face of the needle roller, the crowning amount is 0.1-0.4% of the outside diameter of the axial-direction central portion of the needle roller. Further, in the inner peripheral surface of the output-side disk, there are formed a fitting portion to be fitted outside with a member rotatable in conjunction with the output-side disk and an outer race raceway portion for the needle roller bearing, in the portion of the inner peripheral surface of the output-side disk that is situated near to the inside surface thereof, there is formed a residual compressive stress layer by shot peening, and the outer race raceway portion is ground so as to remove a portion of the residual compressive stress layer, to thereby form the outer race raceway portion as a smooth surface.

The toroidal type continuously variable transmission includes: first and second disks concentrically disposed on each other and supported such that they can be rotated freely; a pair of trunnions; a pair of displacement shafts respectively including support shaft portions and pivot shaft portions; a plurality of power rollers interposed between and held by the first and second disks; a plurality of thrust ball bearings respectively for supporting their associated power rollers; and, a plurality of thrust needle bearings respectively interposed between the outer surfaces of outer rings respectively forming the thrust ball bearings and the inner surfaces of the trunnions. A retainer for retaining the thrust needle roller in a freely rollable manner is formed of a single plate, and is carbonitrided, while the surface hardness Hv of the retainer is set higher than or equal to 550.

Growing community of inventors

Kanagawa, Japan

Seiji Higuchi