Shift drum

The shift drum is a component of a dog gear that is mostly used on motorcycles . It is required to shift a sequential transmission .

functionality

The gearbox consists of a drive shaft , an output shaft and a so-called countershaft . The power is transferred to the countershaft via the drive shaft and from there to the output shaft. Countershaft and drive or output shaft are constantly in engagement with one another via gears . For this reason, one of each gear wheel pair must be connected to the shaft loosely (idler gear) and the other non-rotatably (fixed gear). The power transmission between the two shafts only takes place when a so-called ratchet wheel connects a loose wheel to the shaft in a rotationally fixed manner. These ratchet gears are also fixed gears on their respective shafts. They are shifted to the left or right by the shift gate. The shift gate can be imagined as alleys on the shift drum in which the shift forks run. The shift forks engage in the shift sleeves of the shift gears. As a result of the shifting, the shifting claws of the shifting wheel grip the window of a loose wheel. As a result, the idler gear is non-rotatably connected to the fixed gear and thus also to the shaft.

The shift gate is shifted over the shift drum, which in turn is rotated by the so-called pawl. The switch pawl is operated by the foot switch. The upper gears (2nd, 3rd, 4th, 5th and possibly 6th) are shifted by pulling up the footshift lever, downshifted by pressing down and shifting to 1st gear. In contrast to a car, the gears can only be shifted one after the other. So no gears can be skipped.