Jiaozuo brake

Not only cars, but almost all Almost all cars now use "disc" brakes. It seems that it is hard to find "drum" brakes for family cars now. At present, only some low-end family cars still use the form of rear wheel drum brakes, but the corresponding situation has become less and less.

Drum braking is achieved by pressing the brake shoes against the brake drum. Its advantages lie in slightly lower manufacturing costs and greater braking force. The shortcomings include difficulty in heat dissipation, easy accumulation of water, and the need for regular adjustment of brake shoe gaps. During the braking process of a vehicle, due to inertia, the load on the front wheels often accounts for about 70% to 80% of the total load, so the front wheels require greater braking force than the rear wheels. In order to save costs, the manufacturer has adopted a braking method of front disc and rear drum.

Nowadays, there are fewer and fewer household cars using drum brakes, which can be roughly divided into the following reasons:

1、 Poor heat dissipation

The drum brake wraps the entire braking system inside the brake drum, so there is still a gap in heat dissipation capacity compared to the disc brake, and it is not just a little bit. For large trucks, usually those that use drum brakes are equipped with a spray system to cool down to prevent thermal decay. Generally, when driving in the city, due to road conditions and other reasons, the speed is not fast when intersecting, so there is no phenomenon of thermal recession. The phenomenon of thermal recession often occurs when driving on long slopes down mountain roads. Once it occurs, it is not too much to call it a "nightmare".

2、 Maintenance is cumbersome

A drum brake and a disc brake, upon simple thought, can be understood that the former is definitely much more time-consuming and labor-intensive than the latter. I don't know if everyone has personally changed the brake pads or watched from the sidelines. To change the brake pads of the disc brake (taking the front wheel as an example, if the rear wheel is equipped with an electronic handbrake, some require a computer), simply remove the wheels and remove the brake calipers.

The drum brake is different. It not only needs to pry off the brake drum, but also faces a pile of springs and reeds. If you can't help but blow a breath, the powder will suddenly fly (be careful to protect your eyes). Without special tools, disassembly and installation will be very difficult. After everything is done, you need to adjust the "tightness". The disc brake only needs to press a few feet on the brake.

3、 Braking force and linearity

Due to structural reasons, the drum brake has a greater braking force than the disc brake. Originally, this is a good thing, but such brakes are not linear enough and have too strong force, which has become a disadvantage. If this is used on large trucks, it is not a disadvantage, but when it is put on a household car, a slight force on the brake can instantly stop the wheels, even causing ABS (anti lock braking) to intervene, obviously greatly reducing the comfort and experience of the vehicle.

The non-linear braking force also affects the precise integration of some vehicle stability systems such as ABS and ESP. This is also one of the reasons why there is only "front disc rear drum", and the reason why the front wheels do not need drum brakes is because their braking force is too fast and non-linear.

4、 Weight

To achieve the same braking force, disc brakes are much lighter than drum brakes, and can further achieve weight reduction and thermal aging resistance, such as brake discs made of cast aluminum, ceramics, and other materials. The lightweight of cars is something that car companies around the world are doing, and due to its positioning, few car companies are willing to spend time and effort on weight reduction for drum brakes.

In summary, the reason why cars nowadays use caliper brakes is a result of a comprehensive selection of safety, maintenance, and vehicle body needs. However, this does not mean that the drum brake is not good, it is just not suitable for the current era.