[Catalog:News] [Date:2022-7-1] [Hits:] [Return]

The car can only drive on the road because of the rotation of the wheels. What should we do when the car is about to stop? The driver can't stick his foot to the ground to stop the car like in the animation. At this time, he has to rely on the brake device on the car to slow down and stop the car.

Braking: as the name suggests, it is a mechanical braking device that can slow down the speed, also known as a reducer. To put it simply: the car's brake pedal is under the steering wheel. If you press the brake pedal, the brake lever will be interlocked and pressed, and the brake pads transmitted to the brake drum will block the brake disc, causing the car to slow down or stop running. The car's manual brake is next to the gear and connected to the brake lever. There are also common bicycle brakes, which rely on rod brakes fixed to the frame or disc mounted holding brakes to slow down.

The braking system hidden in the wheel is an important device to stop the moving car. The braking device generates friction between the brake pad and the wheel drum or disc, and converts the kinetic energy of the car into heat energy to be consumed in the process of friction. Common brake devices include "drum brake" and "disc brake". Their basic features are as follows:

1、 Drum brake:

Two semicircular brake pads are installed in the wheel hub, and the "lever principle" is used to push the brake pads to make the brake pads contact the inner surface of the wheel drum and cause friction.

Drum brakes have been used in cars for nearly a century, but due to its reliability and strong braking force, drum brakes are still configured on many models (mostly used in the rear wheels). Drum brake uses hydraulic pressure to push the brake pad installed in the brake drum outward, so that the brake pad rubs with the inner surface of the brake drum rotating with the wheel to produce the braking effect.

The inner surface of the brake drum of drum brake is the position where the brake device generates braking torque. Under the condition of obtaining the same braking torque, the diameter of the brake drum of the drum brake device can be much smaller than that of the disc brake. Therefore, in order to obtain strong braking force for heavy-duty vehicles, drum brakes can only be installed in the limited space of the rim.

Action mode of drum brake

Simply put, drum brake is a brake device that uses the static brake pads in the brake drum to rub the brake drum rotating with the wheel to generate friction and reduce the rotation speed of the wheel.

When the brake pedal is pressed, the force of the foot will cause the piston in the brake master cylinder to push the brake oil forward and generate pressure in the oil circuit. The pressure is transmitted to the piston of the brake cylinder of each wheel through the brake oil, and the piston of the brake cylinder pushes the brake pad outward, causing the brake pad to rub against the inner surface of the brake drum, and generating enough friction to reduce the speed of the wheel, so as to achieve the purpose of braking.

Advantages of drum brake

1. It has the function of automatic tightening, so that the brake system can use low oil pressure, or use a brake drum with a diameter much smaller than the brake disc.

2. The handbrake mechanism is easy to install. For some models with disc brakes on the rear wheels, the hand brake mechanism of drum brake will be installed in the center of the brake disc.

3. The processing and composition of parts are relatively simple and have relatively low manufacturing costs.

Disadvantages of drum brake:

1. The diameter of the brake drum of drum brake will increase after being heated, resulting in an increase in the stroke of stepping on the brake pedal, which is prone to brake response not as expected. Therefore, when driving a vehicle with drum brakes, try to avoid continuous braking, which will cause the brake pad to heat decay due to high temperature.

2. The response of the brake system is slow, and the pedal force of the brake is difficult to control, which is not conducive to high-frequency braking action.

3. The structure is complex and there are many parts, so the brake clearance must be adjusted to make maintenance difficult.

Due to the rapid increase of vehicle performance and driving speed, disc brake has become the mainstream of current brake system in order to increase the stability of vehicle braking at high speed. Because the brake disc of the disc brake is exposed to the air, the disc brake has excellent heat dissipation. When the vehicle makes sudden braking at high speed or brakes many times in a short time, the braking performance is less likely to decline, which can make the vehicle obtain better braking effect and improve the safety of the vehicle.

In addition, due to the rapid response of disc brakes and the ability to make high-frequency braking actions, many vehicle models use disc brakes in combination with ABS systems, VSC, TCS and other systems to meet the needs of such systems for rapid action.