Drum brakes - the so-called brake system, which consists of a rotating drum. In it, braking is achieved by pressing the brake pads against the drum.
As usual, pads in such a system as drum brakes are inside the drum itself. If they are located on the outside of the cast-iron flat disc, then this mechanism is called disk. Drum brakes are still of a different kind - tape. In such a mechanism, braking is carried out by "covering" the drum with a brake metal flexible band.
In such a device, which has two working cylinders, the efficiency of the operation is increased by rotating the drum when the car is moving. During braking, it presses the pads even harder. There is no such effect on the disk mechanisms, since the disk rotates in the direction that is perpendicular to the direction of the braking force. When the machine moves forward, the front shoe starts acting. It is also referred to as a secondary brake shoe (otherwise it is called the rear brake shoe).
It is worth mentioning, what are the main elements of the drum brake. These are the pads that brake. For this, they have lining made of friction material. Also in its complete set there is a brake drum, brake and wheel cylinders. The first of the special fluids listed under pressure, which is in the hydraulic system, comes into play from the brake pedal. All listed parts are mounted on a brake plate (stamped base).
In addition, the drum brakes have the pins (axles) of the brake pads, the mechanisms that regulate the clearance between the drum and the pads, the springs that hold the pads in place and reduce them after the driver releases the brake pedal.
And, of course, it is impossible not to list the advantages of this mechanism. It is used on trucks (most often) and cars. Still can apply on motorcycles. The main advantage of this mechanism is its power. Or rather, the fact that it is extremely easy to increase by increasing the drum diameter and width. Thanks to this, it is possible to achieve high absolute values of braking force, which are necessary to stop and slow down heavy transport (buses, trucks). Drum brakes are perfectly protected against water and dust, or more precisely - from their impact. Pads on dirt or dirt road less wear out - this is an excellent quality, which makes the mechanism durable. If you use it, you can greatly simplify the equipment of the vehicle parking brake. In addition, such mechanisms do not emit much heat, and because of this, non-hygroscopic brake fluids using an alcohol-oil base can be used. Such advantages and have rear drum brakes. It is worth noting only one drawback - the reaction they have a little slower, compared with disk.