Patent ID: 6074324
Filing Date: 2000-06-13
Classification: F16H,Y10T

Abstract:
A toroidal type continuously variable transmission comprising a rotating shaft rotatably supported, an input-side disc that can rotate with the rotating shaft, an output-side disc arranged concentrically with the input-side disc and supported so as to rotate relative to the input-side disc, a plurality of trunnions located in the intermediate portion between the input- and output-side discs in the axial direction of these discs, in the direction perpendicular to the axial direction and at torsional positions relative to the central axis of the discs, the trunnions oscillating at these positions, a plurality of power rollers each rotatably supported on a displacement shaft supported on each trunnion and sandwiched between the input- and output-side discs, and a thrust rolling bearing provided between the outer side of each power roller and the inner side of each of said trunnions, the opposed inner sides of the input- and output-side discs being formed as recessed surfaces of a circular cross section, the circumferential surface of each of said power rollers being formed as a spherical protruding surface, the circumferential surface being abutted on said inner sides, wherein the transmission meets at least one of the following conditions (i) to (iii):(i) of the surfaces of said input- and output-side discs, shot peening is applied to the outer side, and the inner end surface and that part of the inner circumferential surface which is closer to the inner end, both surfaces existing closer to the inner diameter than the inner side that is a circular recessed surface, thereby allowing compressive residual stress resulting from shot peening to exist in the outer side, the inner end surface, and that part of the inner circumferential surface which is closer to the inner end;(ii) heat treated hardened layers are formed on the surfaces of said input- and output-side discs, and of the surfaces of the discs, the outer side and the inner end surface existing closer to the inner diameter than the inner side that is a circular recessed surface have their surface portions cut after the formation of the hardened layers in order to remove abnormal heat-treated layers from these hardened layers;(iii) the amount of whirling of the inner surface of each of said input- and output-side discs relative to the rotational center of each disc is 0.02 mm or less.