SPEED CHANGE APPARATUS FOR POWER UNIT

摘要

A cylindrical shift drum is rotatable around a third rotational axis. The cylindrical shift drum includes at least one lead groove in an outer circumferential surface of the cylindrical shift drum. A shift fork shaft extending in parallel to the third rotational axis is disposed opposite to the outer circumferential surface. At least one shift fork includes a main portion slidably supported by the shift fork shaft and a pin portion rotatably supported by the main body portion. The main body portion includes a fork portion to be engaged with at least one shifter gear. The pin portion is inserted in one of the at least one lead groove. The cylindrical shift drum is to be rotated to guide the pin portion along the one of the at least one lead groove to move the at least one shift fork to shift the at least one shifter gear.

主权项

1. A speed change apparatus for a power unit, comprising:
a main shaft on which a plurality of driving gears are supported; a counter shaft on which a plurality of driven gears are supported; shifter gears included in the driving gears and the driven gears; a cylindrical shift drum formed with lead grooves in an outer circumferential surface thereof; a plurality of shift forks each provided with a fork portion and a pin portion, the fork portion being engaged with the shifter gears, and the pin portion being locked in the lead groove of the shift drum; and a shift fork shaft disposed in parallel to an axial direction of the shift drum and supporting the shift forks in an axially movable manner, gear shift being established by a process in which the shift forks guided by the lead groove of the shift drum and moved in the axial direction moves the shifter gears in the axial direction, wherein the shift forks each includes a main body portion which is provided with the fork portion, and the pin portion of each of the shift forks is provided as a separate body from the main body portion and is rotatably supported by the main body portion.