Working principle of brake caliper

Brake caliper is very important to the braking ability of automobile, and it can be said that it is one of the most important automobile braking parts. In any case, most cars today have disc brakes, at least for the front wheels. But now many cars and trucks also use disc brakes at the rear. In a disc brake system, the wheels of a car are fixed on metal discs or rotors that rotate with the wheels. The work of the calipers is to slow down the speed of the wheel by friction with the rotor.

The brake caliper is mounted on the rotor like a clamp. Inside each caliper is a pair of metal plates bonded to friction materials – these are called brake pads. The outer brake pads are on the outside of the rotor (toward the outside) and the inner brake pads are on the inside (toward the vehicle). When you step on the brake, hydraulic pressure is generated from the brake fluid in the master cylinder to one or more pistons of the brake caliper, forcing the brake pad against the rotor. The brake pad has a high friction surface, which can slow down the rotor or even stop it completely. When the rotor decelerates or stops, the wheels also decelerate or stop because they are connected to each other.

Old cars and trucks use drum brakes, which slow down the movement of the wheels by friction between the rotating drum and the brake shoes installed in the drum. This friction leads to the accumulation of heat and gas in the drum, which often leads to the loss of braking capacity, namely braking attenuation. Because the brake pads in the disc brake system are outside the disc brake system rather than inside the drum, they are easier to ventilate and heat will not accumulate quickly. For this reason, drum brake has been largely replaced by disc brake in modern automobile; However, some less expensive cars still use drum brakes in the rear wheels, so they don’t need much braking power.

There are two main types of calipers: floating (or sliding) calipers and fixed calipers. Floating calipers move in and out relative to the rotor and have one or two pistons only on the inside of the rotor. This piston pushes the entire caliper when the brake is applied, creating friction from both sides of the brake pad rotor. Fixed calipers, as the name suggests, do not move, but have pistons arranged on opposite sides of the rotor. Fixed calipers are usually preferred because of their performance, but they are more expensive than floating calipers. Some high-performance fixed calipers have two or more pairs of pistons arranged on each side of the rotor – some up to six pairs.

Post time: Jun-18-2021