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Vehicle Axles
Axles are an important structural component of a wheeled vehicle. The axles maintain the position of the wheels relative to each other and to the vehicle body. Since for most vehicles the wheels are the only part touching the ground, the axles must bear the weight of the vehicle plus any cargo, and also any acceleration forces between the vehicle and the ground. In addition to the structural purpose, axles may serve one or more of the following purposes depending on the design of the vehicle.
Drive
One or more axles may be an integral part of the drivetrain. A mechanical system (typically a motor) exerts a rotational force on the axle, which is transferred to the wheel(s) to accelerate the vehicle.
Braking
Conversely a vehicle may be slowed by applying force to brake the rotation of the axle. Consumer vehicles' brakes are part of the wheel assembly and therefore exert friction on the wheels directly, but engine braking may still be effected via the axle.
Steering
The front axle of most automobiles is a steering axle. The vehicle is maneuvered by controlling the direction of the front wheels' rotational axis relative to the body and rear wheels.
Gears
A gear is a component within a transmission device that transmits rotational force to another gear or device. The most common situation is for a gear to mesh with another gear, but a gear can mesh with any device having compatible teeth, such as other rotational gears, or linear moving racks. A gear's most important feature is that gears of unequal sizes (diameters) can be combined to produce a mechanical advantage, so that the rotational speed and torque of the second gear are different from that of the first.
Some common types of gears are spur gears, helical gears, double helical gears, bevel gears, hypoid gears, worm gears and rack and pinion gears. Automobiles usually have an epicyclic gear train where one or more of the axes also moves. |
 
 
 
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