The brake disc is also called the brake disc. It is a friction couple on the disc brake. It rotates with the wheels when the vehicle travels. When the vehicle is braked, the caliper clamps the brake disc for friction braking to slow down or stop the vehicle.

In addition to the required strength and rigidity, a qualified brake disc should have as high and stable friction coefficient as possible, as well as appropriate wear resistance, heat resistance, heat dissipation and heat capacity.

1、 Classification of brake disc design structure

1. Solid disk

The solid disk is the most common one and the one used by the original factory. Its structure is relatively simple and the production cost is relatively low.

The advantages are relatively stable, strong and durable. Generally, it can be replaced regularly during use, and the maintenance cost is much lower; The disadvantages are small friction coefficient, poor high temperature resistance, low safety coefficient under high-speed braking or continuous braking, and high fuel consumption.

Generally, solid brake discs are mostly installed on the rear wheels of vehicles or the front wheels of micro vehicles with light loads.

2. Ventilation panel

The ventilation disk can also be called hollow disk. Its interior is hollow. Cold air can pass through the middle to cool down. The ventilation holes can be seen in the longitudinal direction. The internal structure is intricate and staggered. In the past, it was generally designed as a straight channel. Later, with the progress of vehicle technology, it was gradually changed into a curved and pillar channel to improve the heat dissipation function.

The ventilation disc can be regarded as an advanced version of the solid disc. To a certain extent, it can prevent overheating of the brake disc, reduce heat attenuation, and achieve better braking effect. At the same time, since the ventilation disc removes part of the disc body, the self weight is reduced to a certain extent, and the inertia during rotation can be reduced; However, the structure is more complicated and the manufacturing and maintenance costs are higher than those of solid disks.

The ventilation plate is the most common one in the market at present. It is applicable to both front and rear wheels of vehicles.

3. Perforated disc

The perforated plate is perforated on the surface of the ventilation plate to obtain a stronger heat dissipation effect. It is generally used for high-performance sports car running, which can improve the heat decay resistance. In addition, due to the existence of holes, the braking effect can be improved to a certain extent. From the appearance, the perforated disc is also relatively cool, which is deeply liked by the car owners of the appearance Association.

However, with the continuous upgrading of brake disc materials, some people think that it is no longer necessary to drill holes on the brake disc: after drilling on the disc surface, the strength of the brake disc will decrease, and the strength of one more hole will be weak; The balance degree of the brake disc shall be considered in the design of the eyelet. If the distribution is not uniform, it will have a certain impact on the main shaft of the traveling vehicle; Due to the existence of holes, the friction area of the disk surface decreases, and the friction force also has a certain loss; After punching, the heat conduction area of the brake disc surface also decreases, which to some extent counteracts the heat dissipation effect of the ventilation hole; In addition, fine marks or cracks are easy to appear around the hole after a period of use due to the effect of stress. Therefore, these people suggest that car owners who like fast trains or off the track should not use perforated discs.

4. Marking plate

The function of the marking plate is to dissipate the powder generated by the friction between the brake pad and the brake disc as soon as possible through the marking groove, so as to avoid the rolling friction of the dust on the brake disc affecting the braking effect, so as to enhance the friction between the brake pad and the brake disc and maintain a good braking effect.

Secondly, the performance of the marking plate against heat attenuation and water attenuation is also good, and the heat dissipation is relatively fast. It is more suitable for vehicles that often run on mountain roads. Of course, the manufacturing cost is also high, and the supporting brake pads should also be of high specification.

Like the perforated disc, the marking disc also has high requirements for the material and manufacturing process of the brake disc, which requires comprehensive consideration of design. In addition, the marking disc can obtain higher friction, and at the same time, it also means that the wear degree of the friction plate is correspondingly increased.

5. Perforated scoring plate

Also known as "high-speed disc" or "modified disc", it is generally assembled in high-performance vehicles such as racing cars, sports cars or sports vehicles. Although it seems to be a combination of perforated disc and scribed disc, the holes on this type of brake disc may not be completely drilled through, providing heat dissipation performance while maintaining the structure of the brake disc.

Its advantages are that it can be used in a variety of road conditions, has strong thermal attenuation and water attenuation performance, and has good heat dissipation; The disadvantage is that the wear of the friction plate is large, and the material and processing requirements of the brake disc are also high. If there is no corresponding technology or professional guidance, it is better not to DIY by yourself, otherwise the brake disc will break and the consequences will be unimaginable.

6. Wave plate

In contrast, this kind of brake disc is relatively rare. Unlike the ordinary round brake disc, the wavy disc adopts the wavy circumferential design. The biggest advantage is that it is lighter and has better heat dissipation performance. Of course, the more important is the visual design effect. It is generally used in high-end vehicles.

2、 Brake disc material classification

1. Cast iron brake disc

In general, the common brake disc material is gray cast iron 250, referred to as HT250, which is equivalent to the American G3000 standard.

The most obvious advantages of cast iron brake discs are low cost and high strength. Basically, every steel factory has the ability to produce cast iron brake discs. This material is relatively durable and has a high melting point. The heat generated by friction will not soften it easily; The disadvantage is that it is easy to oxidize and rust, and the heat attenuation resistance is slightly poor when braking at high temperature.

At present, more than 90% of the vehicles in the market use cast iron brake discs.

2. Ceramic brake disc

The ceramics mentioned here are not ordinary ones, but carbon fiber ceramics, composite ceramics composed of carbon fiber and silicon carbide at 1700 ℃.

This kind of carbon fiber ceramic brake disc has high efficiency and stable heat attenuation resistance, which is many times higher than that of ordinary brake discs, but its weight is less than 1 / 2 of that of ordinary cast iron discs. This brake disc can immediately generate the maximum braking force at the initial stage of braking, which is faster than the traditional braking system, shorter braking distance and stronger durability.

Carbon fiber ceramic brake disc is a relatively top-grade material at present. Due to the particularity of manufacturing process and material, the price is also relatively expensive. Therefore, it is mostly used in high-end sports cars, and it is difficult to promote it in a large scale on ordinary vehicles.

At present, some manufacturers in the market have also integrated cast iron and carbon fiber ceramic materials to launch a cast iron brake disc with carbon fiber treatment on the surface, which combines the advantages of cast iron and ceramic materials, and the price is also between the two.