When braking, the inner surface of the brake drum rubs with the brake pad to brake. Its manufacturing material is generally gray iron with model HT250. In the case of improper use of vehicle parts by the driver or serious overload, it can cause fragmentation damage to the brake hub, and often cause personal injury in the process of high-speed driving.

The brake hub, also known as the brake drum, is a cast iron piece similar to the tambourine.

The brake drum is an important component of the drum brake system. The inner surface of the brake drum of the drum brake is the position where the brake device generates braking torque. When the same braking torque is obtained, the diameter of the brake drum of the drum brake device can be much smaller than that of the disc brake. Therefore, in order to obtain strong braking force, large vehicles with heavy load can only install drum brake in the limited space of wheel rim. Drum brake system is generally installed in the rear wheels of large vehicles

As far as the wheels of large trucks are concerned, the outside is the tire, the inside of the tire is the steel ring, the inside of the steel ring is the brake hub, the inside of the brake hub is the brake pad, and the inside is the axle.

In the case of direct observation, because the brake hub is inside the tire, people must drill under the car to see it. Among them, the gap between the wheels of the trailer is large, so it is easy to see the structure. If the hub is broken, the debris will fall to the ground between the steel ring and the axle

When the wear amount of brake drum reaches the limit value (for example, the limit value of brake drum with diameter of 180mm is φ 180mm), replace the brake drum.

Carefully clean and check the wear, damage and dimensional tolerance of the brake drum and wheel bolts, as well as whether the inner surface of the brake drum is in good condition. If any problem is found, replace it with a new one.

After the brake drum is repaired, fill the hub with multipurpose grease

The brake hub cracking is a normal phenomenon due to the service life. However, in expressways, the brake hub of some large vehicles often breaks and injures people. The main reasons for the brake hub cracking include:

1. Unauthorized modification of braking device.

Most trucks have been refitted, and many are equipped with drip devices or "brake king". Although these two devices can increase the braking effect when overloaded, they also directly accelerate the cracking of the brake hub. When the truck is overloaded, frequent braking leads to adhesion or heat dissipation, which affects the braking effect and is prone to accidents.

The drip device is to add a water tank on the top of the cockpit to drip to the brake hub in each wheel, and constantly drip water to cool the hub, which can alleviate the brake failure.

"Brake king" is an upgraded version of the brake air pump. After the air passes through the brake pump, the pressure increases, and the brake pads can fit the brake hub more closely, which naturally increases the braking effect. Brake king has more air storage tanks than ordinary brake air pumps.

When the truck leaves the factory, no matter how heavy the load is, its braking system has standards, and within the approved standards, there is no need for dripping water or braking.

2. The main reason is overload

According to the experience of some old drivers, the main cause of brake hub cracking is excessive load. Therefore, even more terrible things will happen.

In addition, auto parts are divided into the main factory and the auxiliary factory. As for the brake hub, each of the main factory is about 600-800 yuan, while the poor or the auxiliary factory produces about 400 yuan. However, the brake drum of Zhengchang also cracked, so the main reason for the accident is the method of use.