Misunderstanding of disc brakes and drum brakes
Date of issue:2016-08-13 00:00 Source:http://en.chezvi.com Click:
The brake system is one of the most important parts of a car. The brake system of modern cars is mainly divided into disc brakes and drum brakes. In order to understand the difference between the two types of brakes, Xiaobian said to the big guy today that the two types of brake systems.
Drum brake
Drum brakes can be regarded as the earliest brake system. It has been nearly 100 years old in the car. The so-called "drum" is the brake drum, which is mounted on the wheel and rotates with the wheel. Inside the brake drum, special brake pads are installed. When a brake action occurs, the brake cylinder piston will push the brake pad outward to cause friction with the brake drum to achieve braking.
The biggest advantage of drum brakes is that under the same braking torque, the diameter of the brake drum is much smaller than the disc diameter of the disc brake. For example, large-scale trucks, buses and other large vehicles generally use drum brakes. In addition, the drum brake structure is simple, the manufacturing cost is low, and the hand brake mechanism is easy to install, so the drum brake is also applied to the rear wheel of the low-end front wheel drive small car.
Drum brakes have the disadvantage of poor heat dissipation. Since the brake operating mechanism is enclosed in the brake drum, heat does not quickly dissipate after repeated heavy braking.
Disc brake
Disc brakes are now the most widely used brake systems on passenger cars. The brake disc rotates with the wheel. When a brake action occurs, the brake cylinder piston on the brake caliper will push the brake disc to grip the brake disc to generate friction and achieve the purpose of braking.
Compared with drum brakes, the biggest advantage of disc brakes is good heat dissipation. Since the entire brake mechanism is exposed, it is also more conducive to heat dissipation. The advantages of disc brakes include rapid response, average braking force, better drainage, and more.
Disc brakes are not without drawbacks. Due to the different working methods, the friction area between brake discs and brake pads is smaller than that of drum brakes, resulting in less braking force than drum brakes. In order to have a better braking force effect, disc brakes must have larger brake discs and larger brake calipers, which will inevitably increase the overall quality of the vehicle.
After these two brakes are finished, let's take a look at the mistakes we often make but do not know.
Misunderstanding 1: "Disc brake is better than drum brake"
This is a misunderstanding of a large part of people. When choosing a car, some people saw that the rear wheel was still frowning with a drum brake. However, we can see from the above description of the working principle that the drum brake with the same diameter is bigger than the brake force of the disc brake. As long as it is properly tuned, the brake distance of a drum brake will definitely not be longer than that of a disc brake. In addition, the matching degree of the tire and the brake system, the weight of the vehicle body, the weight distribution of the vehicle body, etc. all affect the braking distance. The braking effect cannot be drawn directly with the brake system specifications.
Therefore, when we are purchasing vehicles, we must not rashly rearrange the rear drum brake.
Misunderstanding 2: "The same four-wheel disc brakes, the larger the brake disc diameter, the better"
For different models of different brands of models, this argument can not be established. The reason is that we have said above that the braking performance and braking distance have a lot to do with the depot adjustment, and there are many other factors that will have an impact. If the brake caliper is not strong enough, the friction coefficient of the brake pad is not high, and the grip of the tire is not enough. Simply relying on increasing the brake disc does not make a great leap in the braking performance of the vehicle.
Misunderstanding 3: "The original brake is too bad, I went to modify a multi-piston brake caliper"
It is recommended to be cautious when doing brake modifications, because the brake system of each model is matched by the precise design and long-term test of the car manufacturer, and any modification may damage the brake balance. Modification of the brake caliper will likely cause greater wear on the original brake disc, and it will be difficult to improve brake performance if the brake tubing, brake oil, etc. are not upgraded together. BMW, which places great emphasis on performance, insists on the use of single-piston brake calipers on most of its production models. This also proves from one side that the multi-piston caliper is not a good medicine for improving brake performance.
