What Role Does the Brake Drum Play?

Brake drum is the friction pair of the drum brake. In addition to the required strength and stiffness as a component, it should also have a high and stable coefficient of friction, as well as a corresponding wear resistance, heat resistance, heat dissipation and heat capacity, etc.

• What role does the brake drum play?

• What types of brake drums are there on the market?

• Where are the brake drums installed?

What role does the brake drum play?

The brake drum is a cast iron piece in the shape of a tambourine that is attached to the tire and rotates at the same speed. When braking, hydraulic pressure is used to press the brake shoes so that they touch the inner edge of the brake drum, and the friction generated by the contact is used to limit the rotation of the tire to achieve the purpose of braking. Drum brakes consist of brake base plate, brake cylinder, brake shoes and other associated connecting rods, springs, pins and brake drums. Currently used only frequently on the rear wheels. The cost of drum brakes is lower and the absolute braking force is higher, and they are more often used in the rear wheels of small cars.

What types of brake drums are there on the market?

There are two types of brake drums, cast and combined.

Casting brake drums are mostly made of grey cast iron, which has the advantages of easy machining, wear resistance and large heat capacity. To prevent the brake drum from deforming under load during operation, ribs are often cast on the outer circumference of the brake drum to increase stiffness and heat dissipation effect. Accurate calculation of the wall thickness of the brake drum is complex and difficult, so it is often selected based on experience. The thickness of the brake drum wall of the car is 7-12 mm and the thickness of the truck 13-18 mm.

The cylindrical part of the combined brake drum can be cast from cast iron and the web part can be punched from sheet steel; it is also possible to insert centrifugally cast alloy iron parts on the inside of the brake drum punched from sheet steel to form the brake drum; or the base body of an aluminium alloy, with a layer of grey cast iron of perlite as a working surface. Common features of combined brake drums are low mass, wear-resistant tread and high coefficient of friction.

Where are the brake drums installed?

The brake drum is the inside of the tire and the side that is close to the chassis of the car. On some cars, you can see it through the steel rim of the tire, but some steel rims are massive and you can see it clearly when you remove the tire. It should be said that the tire is attached to the "brake drum" with screws. Drum brakes use the brake transmission mechanism to make the brake shoes press the brake pads on the inside of the brake drum to generate braking force, slow down the wheels as needed or stop within shortest distance to ensure driving safety, and ensure that the car is safely parked and cannot slip automatically

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