TRANSMISSION

摘要

A transmission in which gear trains with multiple shift gear stages are selectively positionably installed between a first main shaft, a second main shaft coaxiallv and relatively rotatably extending through the first main shaft, and a countershaft. Between the second main shaft (27) and the countershaft (28), on the opposite side of first and second clutches (37, 38), there is disposed a first speed gear train (G1) to form gear trains (G1, G3, G5) for odd-numbered shift stages. The first speed gear train (G1)-side end of the second main shaft (27) is rotatably supported by an engine body through a main shaft-side ball bearing (31) having a larger outer diameter than a first speed drive gear (89) formed integrally with the second main shaft (27). An outer ring (31a) of the ball bearing (31) on the main shaft side is fixed to the engine body through a fixing plate (95) engaged with the outer periphery of the outer ring (31a). The transmission is compact in the direction along the axis of the first and second main shafts.