Bus Brake Linings

Buses is any type of motor vehicle used for transporting goods or paying passengers. Baiyun develops and manufactures drum brake linings for buses including truck & bus which require powerful braking force.

For large buses, strong braking forces are required. To this end, drum brakes linings are widely used because they are more lightweight and costs less that disc brakes, while capable of delivering more braking force.

Drum Brake Linings for Buses

Drum brake is a brake that uses friction caused by a set of shoes or pads that press outward against a rotating cylinder-shaped part called a brake drum. Drum braking linings have brake drums that rotate with the wheels.

Brake shoes fitted with drum brake linings (friction material) which press against the drums from the inside to generate braking force (decelerate and stop) are set inside of the drums.

With this system, friction is generated by pressing the brake linings against the inside surfaces of the drums. This friction converts kinetic energy into thermal energy. Drum rotation helps to press the shoes and the lining against the drum with more force, offering superior braking force in comparison with disc brakes. On the other hand, it is very important to design the components so that the heat from the thermal energy is dissipated efficiently into the atmosphere.

There are three types of drum brakes depending on how the brake shoes are pressed on to the drums; leading/trailing shoe type, twin leading shoe type and duo-servo type.

Structure of drum brakes

Drum brakes are a brake system with brake drums (rotor) which rotate with the wheels. Inside each drum are brake shoes fitted with brake linings (friction material). Pistons (pressure mechanism) press against the drums from the inside to generate braking force, thus making is possible to decelerate and stop the vehicle.

How drum brakes work

When the driver steps on the brake pedal, the power is amplified by the brake booster (servo system) and changed into hydraulic pressure (oil-pressure) by the master cylinder. The pressure reaches the brakes on the wheels via tubing filled with brake oil (brake fluid). The delivered pressure pushes the pistons on the brakes of the four wheels. The pistons press the brake linings, which are friction materials, against the inside surfaces of the brake drums which rotate with the wheels. The linings are pressed on the rotating drums, which in turn decelerate the wheels, thereby slowing down and stopping the vehicle.

Main components of drum brakes

Friction Materials

1, Friction Raw Material

2,Types of friction materials

*1 Sintered alloy: The phenomena where the particles of powder material join together and turns into a solid substance by pressurizing and fabricating the powder material and heating it at temperatures below the melting point. Material that is not made by melting metal, but instead by sintering metal powders is called sintered alloy.

*2 C/C composite: Carbon fiber reinforced carbon composite. Carbon composite material has been strengthened with carbon fiber. It is extremely thermally stable and lightweight. This material is often used for brake rotors and brake pads for aircraft and racing cars.

3, Friction Material of Baiyun

4, Manufacturing process of friction materials

Producing Equipment

R & D Units