Belt-type continuously variable transmission and straddle-type vehicle
AssigneeYamaha Hatsudoki Kabushiki Kaisha
InventorsYousuke Ishida, Akifumi Oishi, Takuji Murayama
Life of this patent
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Abstract
Abrasion of a V-belt in a belt type continuously variable transmission accommodated in an engine unit of a motorcycle is suppressed. A V-belt wound around and contacting a primary sheave and a secondary sheave 72 is at least partially formed from a resin. A plurality of grooves aligned at a predetermined pitch in a radial direction are formed on sheave surfaces of the primary and secondary sheaves. The average pitch P(mm) of the grooves is P≦−0.08K×10−3+0.18, where K(Hv) indicates surface hardness of the sheave surfaces.
Claims20
A belt type continuously variable transmission comprising:
- a primary sheave made of metal,
- a secondary sheave made of metal, and
- a V-belt wound round and contacting the primary sheave and the secondary sheave, and being at least partially formed from a resin, and wherein
- a plurality of grooves aligned in a radial direction of the sheaves are formed on a sheave surface of at least one of the primary and secondary sheaves,
- an average pitch P(mm) of the grooves is P≦−0.08K×10−3+0.18, where K(Hv) indicates surface hardness of the sheave surface, and
- a ten-point mean roughness Rz of a sheave surface, on which the plurality of grooves are formed, is 0.5 μm≦Rz≦10 μm.
A method of manufacturing a sheave of a belt type continuously variable transmission, which comprises a primary sheave made of metal, a secondary sheave made of metal, and a V-belt wound round and contacting the primary sheave and the secondary sheave, the V-belt being at least partially formed from a resin, the sheave being the primary sheave or the secondary sheave, the method comprising the steps of:
- forming a plurality of grooves aligned on a sheave surface in a radial direction of the sheaves, wherein an average pitch P(mm) of the grooves is P≦—0.08K×10×3+0.18, where K(Hv) indicates surface hardness of the sheave surface, and
- applying plating to that sheave surface, on which the grooves are formed, wherein
- a ten-point mean roughness Rz of a sheave surface, on which the plurality of grooves are formed, is 0.5 μm≦Rz≦10 μm.
Dependencies are inferred from the claim text.