DRUM TYPE-VARIABLE SPEED DRIVE

摘要

A drum type-variable speed drive wherein a spring bearing member, which is restricted from moving in the axial direction of departing from a shift fork by a locking member fixed to a shift fork shaft, is pivotally supported by the shift fork shaft. A lost motion spring is interposed between the spring bearing member and the shift fork. Movement of the shift fork shaft in the axial direction caused by rotation of a shift drum presses the spring bearing member through the locking member, whereby the spring load of the lost motion spring acts on the shift fork.

主权项

1. A drum type-variable speed drive in which an engaging pin portion of a shift fork pivotally supported by a shift fork shaft in a slidable manner slidably engages with a fork guide groove on the outer peripheral surface of a shift drum, and with rotation of said shift drum, said shift fork moves in an axial direction while being guided by said fork guide groove, to thereby move a shifter member of a transmission engaged with said shift fork and drive the gear shift, wherein:
said shift fork shaft is supported by an engine case so as to be moveable in the axial direction; a shaft pin is provided on said shift fork shaft so as to protrude toward said shift drum; a shaft guide groove with which said shaft pin slidably engages is formed on said shift drum; a spring bearing member, which is restricted from moving in the axial direction of departing from said shift fork by a locking member fixed to said shift fork shaft, is pivotally supported by said shift fork shaft; a lost motion spring is interposed between said spring bearing member and said shift fork; and movement of said shift fork shaft in the axial direction caused by rotation of said shift drum presses said spring bearing member through said locking member, whereby the spring load of said lost motion spring acts on said shift fork.