Component parts of a toroidal-type continuously variable transmission having improved life
AssigneeNsk Ltd.
InventorsNobuaki Mitamura, Tsutomu Abe, Hideki Kokubu
Life of this patent
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Abstract
In a toroidal-type continuously variable transmission including input and output side disks and a pair of power roller bearings, rolling elements of the power roller bearings are made of a steel which is to be case hardened, a medium-carbon steel or a high-carbon steel which is such a steel as containing carbon in an amount of 0.2 wt % or more, and are subjected to a carbonitriding process and hardening and tempering treatments. The toroidal-type continuously variable transmission has a long life by improving the rolling life of the power roller bearings, the input side disks, and the output side disks.
Claims12
A toroidal-type continuously variable transmission comprising:
- an input side disk disposed on an input shaft;
- an output side disk disposed on an output shaft;
- and
- a pair of power roller bearings disposed between the input and output side disks, each of the bearings including an inner race, an outer race, and a plurality of rolling elements interposed between the inner and outer races and transmitting motive power of the input shaft to the output shaft while engaging the inner race with the input and output side disks, wherein each of the rolling elements has a residual compressive stress ranging from 19 to 74 kgf/mm.sup.2 in its rolling surface, and wherein each of the rolling elements has carbon and nitrogen dissolved in a surface layer of its rolling surface by means of a carbonitriding treatment.
Dependencies are inferred from the claim text.