Shift Possibilities (gearbox)
Modern gearboxes should enable the driver, unlike the sequential gearbox, to directly engage any gear he chooses. It must not be necessary to go
through all the gears, e.g.,
when after stopping, and he needs to change from 5th gear into 1st gear.
|Why the H-pattern is used in gearboxes|
As already explained in coaxial and non-coaxial gearboxes, the sliding
clutch allows the connection of a single gear wheel
with the shaft. It is operated by the respective shift fork and the selector shaft. The gearshift engages this in such a way, that in one direction the right changing lane is chosen, so that in the other direction, the movement
of the gear is possible. Each lane is exited in the middle because the gearbox would lock if two gears were engaged at the same time. For this reason the 'H' layout was developed.
|Linkage bar system - versus Bowden cable-system|
In this case a coaxial gearbox was selected for the configuration, front engine with rear-wheel drive and synchronised reverse gear, to be able to show the principle of the circuit better. Nowadays, with most gearboxes,
the gearshift action to the gearbox using linkage bars is less common than gear shifting using two Bowden cables. Although the linkage bar system is more easily operated as a rule, the cable system offers more
flexibility in the construction and probably also lower costs.
|Transfer of power to the reverse gear is sometimes complicated|
The position of the reverse gear opposite the fifth gear is a little unusual. If it lies, in the five-speed gearbox, next to the first gear, another selector shaft is necessary. Also the connection of the selector shaft to the sliding
clutch, or to the diverting cog in an unsynchronised reverse gear, is often carried out by one or two levers, possibly in the form of a rocker arm. 09/08
* Reverse gear synchronised -> s,
|Number of components in a conventional gearbox|
|speeds||4 u*||4 s*||5 u*||5 s*||6 u*||6 s*|
|Gear changing shafts||3||3||4||4||5||5|
Reverse gear unsynchronised -> u