1. The drum brake
The drum brake, also known as brake blocks, brake pads against a brake wheel brakes to achieve compression. Drum brake is an early design of the braking system, brake drum design that has been used in 1902 on the carriage, until around 1920 began widely used in the automotive industry. It is now the mainstream of the drum brake type sheets, which brake shoe (brake shoe) located inner wheel braking, when the brake pad braking outwardly flared, inner friction wheel brake, braking purposes. Nearly three decades, the drum brakes on the car in the field has given way to gradually withdraw disc brakes. However, due to relatively low cost, is still used in some cars in the economy class, mainly used for braking the rear wheel load is relatively small and the parking brake.
Composition
rotating element
of the drum brake is a brake drum, a brake shoe fixing element. Brake shoe drum brake braking rotation outwardly under action of the actuating means, the friction plate pressed against the outer surface of the inner cylindrical surface of the brake drum, the drum to generate a braking friction torque.
Where the end of the hoof that the urging means to rotate collectively shoe brake shoe actuating means, the actuating means has a brake shoe wheel cylinders, wedges, and cams. Hydraulic wheel cylinders as a brake shoe actuation device called a brake wheel brake cylinder; the cam brake actuating apparatus as called cam brake; wedge brake actuation device as called wedge brake.
The drum brake place is complex, a number of drum brakes are self-acting. When contacting the drum the brake shoe occurs, there will be some wedging action, the effect is greater braking force by the brake shoe is pressed into the drum. Additional braking force provided by the wedging action, so that the drum brake can be used with the disc brake than smaller piston. However, due to wedging action when the brakes are released, the brake shoes to be disengaged from the drum. This is needed for some reason spring. Other spring brake shoes will help to fixIn place, and returns it after adjusting arm drive.