11:15. Drum brake mechanisms - the general information

Typical design of the drum brake mechanism

1 — Pruzhina of fastening of a boot to the regulator lever
2 — the Top coupling spring
3 — Assembly of the regulator
4 — the Wheel cylinder
5 — the regulator Lever

6 — the Directing springs
7 — Anchor fingers of the directing springs
8 — the Lower coupling spring
9 — Brake boots
10 — the Executive lever of the drive of the parking brake

The typical design of the drum brake mechanism is presented on an illustration.

Two boots equipped with frictional slips are established on not movably fixed brake board. Boots are concluded in the drum rotating together with wheel assembly. Boots are fixed on the seats by means of springs that provides them a certain extent of movement with a possibility of a clip to the working surface of the reel. The clip of boots to a drum is carried out due to the effort developed by pistons of the wheel cylinder when squeezing by the driver of a pedal of a foot brake. Nestling a surface of frictional slips on drum walls, boots interfere with its rotation therefore process of braking of the vehicle is carried out. At release of pressure in a hydraulic path boots, due to the effort developed by coupling springs come back to a starting position, wringing out pistons and releasing a drum.

Modern drum brake mechanisms are equipped with the self-regulators providing compensation of wear of frictional slips. Regulators work automatically when braking of the car moving a backing.

 On some models self-regulators work at each braking of the car.