Gearing Up with Gearboxes

Posted on September 24, 2019 Jerold Perkins Aviation

What is a gearbox? Aside from being a horribly expensive thing to repair and replace, of course. The transmission box, or gearbox, is the second element of the powertrain in an automobile or any vehicle that uses an internal combustion engine, with the first being the engine. It is used to change the speed and torque of the vehicle according to the conditions of the road and the load the powertrain is trying to carry. Transmission boxes change the engine’s speed into torque when climbing hills and other situations that require it.

The main function of a gearbox is to provide the torque needed to move the vehicle under a variety of road and load conditions by changing the gear ratio between the engine crankshaft and the vehicle drive wheels, as well as to shift into reverse so that the vehicle can move backwards, and to shift into neutral for when starting the engine.

The counter shaft: A shaft that connects with the clutch shaft directly, and contains the gear which connects it to the clutch shaft and the main shaft as well. The counter shaft can be run at engine speed or lower according to the gear ratio.
The main shaft: The shaft that runs at the vehicle’s speed, the main shaft carries power from the counter shaft by using gears and according to the gear ratio. The main shaft runs at a different speed and torque compared to the counter shaft.
Gears: Used to transmit power from one shaft to another, gears are the most useful component in the gearbox because the variation of torque between the counter shaft and main shaft is dependent on the gear ratio. The gear ratio is the ratio of driven gear teeth to the driving gear teeth. If the gear ratio is larger than one, the main shaft revolves at lower speeds than the counter shaft, and the torque of the main shaft is higher than the counter shaft. If the gear ratio is less than one, the main shaft revolves at higher speeds than the counter shaft, and the torque of the main shaft is lower than the counter shaft. An automobile gearbox will typically contain four speed gear ratios, and one reverse gear.
Bearings: Bearings support rotary motions and reduce friction between moving parts. In a gearbox, both the counter and main shaft are supported by bearings.

In a gearbox, the counter shaft is matched to the clutch with the use of gears. When the counter shaft is brought into contact with the main shaft, the main shaft starts to rotate according to the gear ratio. When the driver wants to change the gear ratio, they press the clutch pedal, which disconnects the counter shaft with the engine and connects the main shaft with the counter shaft by another gear ratio by using the gearshift lever. In a gearbox, it is critical that the gear teeth and other metal parts do not touch and are separated by a thin film of lubricant. This prevents excessive wear and tear on parts and keeps them from failing early.

At Aerospace Exchange, owned and operated by ASAP Semiconductor, we can help you find all gearbox systems and parts for the aerospace, civil aviation, and defense industries. We’re always available and ready to help you find all the parts and equipment you need, 24/7-365. For a quick and competitive quote, email us at sales@aerospaceexchange.com or call us at +1-714-705-4780.