The drum brake has a good self-control effect, because the brake disc is open and the wheel is rotated. Even if the angle of the wheel is twisted in the brake drum, the greater the braking tension is, the more obvious the braking tension is. Therefore, the general large vehicle or the use of the drum brake, in addition to reducing the cost, the difference may be very atmospheric. Dynamic assist, and small car to help vacuum assisted brake.
Drum brake is the earliest brake system because of its low manufacturing technology level, so the manufacturing cost is lower than that of disc brake.
The brake drum is used to seal the disc to the brake drum, which causes the contact surface of the brake disc wear debris. After brake drum is trapped, the brake will be affected by the brake drum.
Because the brake system is not sealed, the brake fine brake wear is not deposited, and the centrifugal disc brake can be thrown out of all water, dust and other pollution to maintain a certain degree of cleanliness. In addition, due to the independence of the outer part of the brake drum brake, maintenance ratio
Disc brakes are more expensive than drum brakes and disc brakes, which are also known as disc brakes. As the name suggests, they are named in their shape. It is controlled by hydraulic pressure, fast and light in brake, light in weight, simple in structure and easy to adjust. In particular, the high and low temperature performance of high load, stable braking effect, and not afraid of mud intrusion, driving and road conditions are not good, in winter, it makes it easier for the disc brake to stop the car in a shorter time than the drum brakes.
In some of the disc brake has also opened many small holes, accelerate the ventilation to improve the braking efficiency. In contrast, drum brake, because of its poor heat dissipation, will accumulate a lot of heat during the braking process. Under high temperature, the deformation of brake shoes and drum is more complex, which is likely to cause brake degradation and trembling, resulting in braking efficiency reduction. Of course, disc brakes also have their own defects. For example, brake and brake pipe manufacturing is higher, the wear of friction plate is more expensive and expensive, and because of small area of the friction plate, the requirement of high pressure relative to the working face of the friction brake is that the vehicle must be used by the auxiliary device, so it is only suitable for light vehicles. Drum brakes are relatively cheap and more economical.
Therefore, from the economic and practical point of view, automotive designers generally need the form of hybrid electric vehicle, front wheel brake and rear drum brake. In the four wheel car in the braking process, the effect of inertia, the load in the front wheel is usually 70%, it is all the car load -80%, therefore, the rear wheel brake force ratio is larger. In order to save cost, automobile manufacturers use front wheel disc brake and rear drum brake. The four wheel brake class car, the front wheel ventilation disc brake better heat dissipation, because the use of non ventilated rear disk is also the reason for the cost. After all, the manufacturing process of ventilating disc is much more complicated, and the price will be relatively expensive. With the development of science and reducing the cost of materials, in the field of automobile, disc brake has a tendency to replace drum brakes gradually.
The ventilating disc is made up of two brake discs which constitute the same size and the vent between them. When the brake disc rotates together, it will be like a pump, which is discharged from the hot air between the two discs for cooling purposes.