V-belt type continuously variable transmission
A V-belt type continuously variable transmission includes a drive pulley assembly provided on a drive shaft, a driven pulley assembly provided on a driven shaft, a V-belt looped over both the pulley assemblies, and a transmission case assembly housing both the pulley assemblies and the V-belt. One end of the drive shaft in the shaft direction is coupled to an output side rotation member of a centrifugal clutch, and the other end of the drive shaft is rotatably supported on a boss portion formed in the transmission case assembly.
1. A V-belt type continuously variable transmission attached to a crankshaft of an engine via a centrifugal clutch, comprising:
a drive pulley assembly provided on a drive shaft;
a driven pulley assembly provided on a driven shaft;
a V-belt looped over both the drive pulley assembly and the driven pulley assembly; and
a transmission case assembly housing the drive pulley assembly, the driven pulley assembly, and the V-belt, wherein:
one end of the drive shaft in the shaft direction is coupled to an output side clutch housing of the centrifugal clutch;
the other end of the drive shaft is rotatably supported on a boss portion formed in the transmission case assembly;
the transmission case assembly includes a transmission case body fixed to or integrally formed in the crankcase of the engine, and a transmission cover made of aluminum or an aluminum alloy;
the transmission cover is attached to the transmission case body;
the boss portion is formed in the transmission cover;
a plurality of reinforcing-ribs are formed in the transmission cover so as to extend radially from a center of the boss portion; and
a plurality of rear reinforcing-ribs are formed in a rear half part of the transmission cover so as to extend in a substantially up and down direction.
2. The V-belt type continuously variable transmission according to claim 1 , wherein:
the rear reinforcing-ribs are arranged at intervals from each other in the front and rear direction;
one of the rear reinforcing-ribs arranged at a rear-most side of the transmission cover is formed in an L shape; and
another one of the reinforcing-ribs arranged at a front-most side of the transmission cover is formed in a linear shape.
3. The V-belt type continuously variable transmission according to claim 2 , further comprising a centrifugal clutch housing and a centrifugal clutch cover, wherein the one end of the drive shaft is formed integrally with a boss portion of the centrifugal clutch housing, and the boss portion of the centrifugal clutch housing is rotatably supported on an inner peripheral surface of a centrifugal clutch cover.
4. The V-belt type continuously variable transmission according to claim 3 , wherein the centrifugal clutch cover is integrally formed with the transmission case body.
5. The V-belt type continuously variable transmission according to claim 2 , wherein a seal is arranged on a mating surface between the transmission cover and the transmission case body.