We all know that in the current family car, the choice of braking method is nothing more than disc brake (disc brake), and drum brake (drum brake), in the eyes of the vast majority of people, disc brake represents the high-end, drum brake represents the backward, but the internship is really so.

1. disc brake (disc brake)

1. Components

Usually the primary components of disc brakes are: brake master cylinder, sub-cylinder, brake disc, brake caliper, brake pad, oil pipe and so on.

2. Braking principle

The braking principle of the disc brake is very simple and very easy to clarify. When the vehicle needs to slow down, the brake caliper will clamp the brake disc, and the brake pad and the brake disc will slow down the car, just like you You can use two fingers to clamp a piece of paper. The brake caliper is advanced by the brake piston, and the power of the brake piston comes from hydraulic pressure. In the process of braking, the original mechanical energy of the vehicle is converted into heat energy and then thrown away in the air.

3. Advantages

Because the brake disc of the disc brake is exposed to the air, the brake disc is directly air-cooled during driving, which can be cooled relatively flexibly and prevent the brake from showing thermal attenuation quickly. In addition, the force of the piston pushing the brake caliper to clamp the brake disc has a linear relationship with the force of the driver stepping on the brake, and the driver can control the braking force more simply.

4. Defects

Only cars that use disc brakes need to be equipped with a booster system for the brakes. Since the required braking force cannot be reached by the driver's foot alone, most vehicle booster systems rely on vacuum brake booster pumps. The vacuum force generally comes from the negative pressure generated by the engine intake manifold. This also explains the time when you only need to "brake with one foot" after the parking is turned off. Since there is no boost when the second foot is braked, the brake pedal is as hard as a stone.

2. drum brake (drum brake)

1. constitute some

A typical drum brake is mainly composed of a bottom plate, a brake drum, a brake shoe, a wheel cylinder (brake cylinder), a return spring, a positioning pin and other parts.

2. Braking principle

The brake drum is installed on the wheel hub and is a component that rotates with the wheel. It is made of a certain amount of cast iron and is shaped like a circular drum. When braking, the wheel cylinder piston pushes the brake drum (inside), and the brake drum is decelerated by conflict, forcing the wheels to stop rolling.

Of course, the processing and composition of drum brake parts are relatively simple, and then the production cost can be reduced very well, which is why we think drum brake is a simple matching and unconscience element address.

3. Disadvantages

Because of a nearly closed brake drum, the heat dissipation of the drum brake is much worse than that of the disc brake. The diameter of the brake drum will increase after being heated, and then the stroke of stepping on the brake pedal will increase, and the brake will appear very simple. Thermal attenuation phenomenon.

Compared with disc brakes, drum brakes have another advantage that does not seem to be an advantage-the return spring. Due to the existence of the drum brake return spring, when braking (release the brake) is not needed, the brake shoe and the brake drum It can be separated instantly, and the rated power will not be wasted at all, and the separation of the disc brake pad and the brake disc is not so fast. This waste of energy is very small, but a pure electric car with a small capacity battery means it can run farther.