Trailer Axles - Types and Features

In modern or commercial vehicles, axles are most commonly used internal component which serves multiple requirements which include driving, braking, gearing and steering functions. Overtime, the designed of axle has been modified, to suits the requirement and to ensures an appropriate level of structural support.

An axle is fixed straight shaft, which is usually used to mount rotating wheels or gears. An axle can be connected with vehicle by either of two ways, It can be simply fixed to the wheels by using bushing or bearing. Or, in other way, it can be mount to its surrounding parts by fixing bearing and bushing in center of the wheel, thereby connecting two wheels to allow it to rotate without effecting the axle.

In vehicles, axle plays a significant role in keeping the wheels in right position. The main purpose of using axle is to secure the fixed position of wheel and gear, by transmitting the torque or braking and acceleration force away from the wheels. Axles are also used to bear the weight of the vehicle and the cargo, as well as to balance the force and speed of the vehicle and prevent wheel to bend and become flat. Without an axle, the wheels of vehicle would not functions in proper manner. Further, axle also helps in maintaining the alignment of wheels.

Types of Axles

Broadly classified in two types, i.e., Live or Dead. Former, means these types of axles moves with the rotation of the wheels, or revolve with the wheels. Live axles are mainly used in modern cars, having rear wheels as driving wheels. Whereas, dead axles are stationary axles and hence, doesn't revolve with the movement of the wheels.

Live axles are further classified as follows:

Semi Float - These types of axle are designed which carry the weight and rotational torque of vehicles on the shaft itself. There is a separate shaft's housing outside the bearing and axle through which axle rotates and carries the entire weight of vehicle. In this design, axle itself act as inner bearing race, which is suitable for lighter trucks or passenger vehicles like buses. They have the capacity to bear weight maximum of 1/2 tons.

Three quarter floating axles- These types of axles have shafts which are supported by wheels to form a rigid unit with the shaft and depend on it for alignment. It is almost similar to the semi-floater, in three quarter floating axle, weight and rotational torque is bear by the outer bearing of the shaft axle which is mounted between the axle housing and hubs. Three-quarter floating are also used in light commercial vehicles. But, with the improvement in designs, materials and fabrication techniques it was being replaced by semi float axles, as latter are simple in design and cheap.

Full Float axles- In these types of axle, bearing is places outside the housing which results in transmitting of vehicle's weight on the axle housing from the axle. Full float also absorbs all type of rotational torque and stress. This design of axle is suitable for most heavy trucks and these are costly also.