A brake system of a vehicle can apply certain force on the wheels to brake them to a certain extent. The functions of a brake system are to forcibly make the moving vehicle decelerate or stop according to the driver’s instructions, to park the moving vehicle steadily under various road conditions, including on a ramp, and to keep the vehicle at a stable downhill speed.

A brake system can be categorized into a disc brake system or a drum brake system;a drum brake system is a traditional brake system, which is composed of a brake oil pump, a piston, brake pads and a drum compartment. In braking, the high pressure brake oil out of the braking oil pump will push the piston, and the piston will further apply some force on the two half-moon brake shoes to make them press tightly the inside wall of the drum compartment, thus preventing the brake drum from turning by friction and realizing a braking.

A drum brake system equipped with some additional pneumatic aid, is generally adopted in a heavy-duty truck and a bus; while a disc brake system is adopted in a car. The main advantages of a drum brake system are less wearing of the brake shoes, lower cost, and easy maintenance. Because the absolute braking force of a drum brake is much bigger than that of a disc brake, it is widely used on rear wheels braking in a truck.

鼓式制动器

Brake shoe

When being used, the brake shoe as a braking part will be pushed outward to press with its friction plate tightly against the inner radius surface of the braking drum. Then a friction moment can take place owing to the non-rotating brake shoe touching the rotating braking drum, thus providing a braking force on the braking drum. The brake shoe is one of the most critical safety-related parts of a brake system in a vehicle.

Braking shoe

Technological requirements

The brake shoe consists of a friction shoe pad and a shoe rib being welded together. The thickness is normally within a range of 6 - 8 mm, and the welding is done by a positioning hole-plug welding method.

1. The penetration depth and strength of each welding spot shall be ensured, and all welding spots shall be uniform and consistent without any crack, undercut, or incomplete fusion or other defect.

2. Welded shoe pad shall be free of spillage, thus lessening subsequent grinding.

3. Two welding machines work together with the special machine to ensure the consistence of welding. It is needed to keep the output welding voltage consistent.

4. Continuous welding of 24 hours for the machines will offer better fatigue resistance and stability.

Cross section of welding position

Our solution

The wholly-digital industrial heavy-duty machine of Ehave CM500H is applied according to the customers’ demand, with 1.2 mm solid carbon steel wire used with CO2 for spot welding, and the current being in a range of 300 A - 350 A. Its temporary load capacity of 500 A at 100% is ideally suitable for the welding of high current and deposition efficiency, with stable, centralized and strong-penetrating arc, and less spillage. 

Spot welding function of Ehave machine can precisely ensure the time of simultaneous welding of the two welding machines, avoiding the disturbance of their welding rhythm out of different welding time which may affect the production rate and welding form. With the same penetration depth, contrasted with other gas-shielded welding machine, its thermal output is reduced by 20% or more, with less thermal deformation.

With the droplet necking inspection and control micro-technology adopted, there are no small balls at the end of welding wire when the output is switched off after the last droplet transition is completed, ensuring that after the long continuous plug welding, the subsequent arc starting features its stability and consistence.

Welding effects

Summary

Contrasted with the traditional thyristor machine, with the equal parameters, Ehave wholly-digital machine will feature lower energy consumption, thus greatly reducing the production cost. The high speed fully-digital control system can monitor each phase of the droplet transition, ensuring that each output is stable and consistent, and the system is equipped with the first-class power supply anti-interference design in this industry. Even at the extreme temperature, power grid fluctuation, surge impact, high-frequency conduction and radiation and the like, high quality and stable welding can be realized.