Saturday, March 22, 2014
Basic Operation of Gearboxes
All cars have some sort of transmission, be it automatic, manual or continuously variable. Only manuals are erred to as "gearboxes," since they use only a set of gears instead of a series of clutches and shafts.
Purpose
Transmissions use differential gear ratios to multiply engine torque, helping the car to accelerate quicker at low speeds. Torque multiplication is directly related to the number of teeth on the input gear vs the output gear. Example: if the input gear has 10 teeth and the output gear has 30, gear reduction comes out to 3-to-1.
Basic Parts
A normal gearbox has an input shaft and an output shaft with a number of gears mounted to each. As you move along the transmission, the gears on the input shaft get larger while those on the output shaft get smaller.
Engagement
The input and output shaft gears are in constant mesh, but the output shaft gears simply freewheel on the output shaft until the driver locks the two together. When the driver engages the gear, a cog fixed to the output shaft slips inside a receiver hole in the output gear, locking the output gear to the shaft.
