What is Disc Brake? How Disc Brake Works

Today’s motorcycles and cars are equipped with very efficient braking systems. They are so efficient that in case of emergency your vehicle comes to a halt safely within a fraction of a second. When you pull the brake lever, the brake fluid near the lever is pressurized through the brake line, this pressurized fluid attaches to the brake pads of the wheel and the brake pads are activated. This braking system that you have just seen was developed in the last 5 decades of research and practical experience, let us find out how engineers developed such an efficient braking system or more specifically let’s get behind the disc brakes Learn physics, you may be wondering how the small force produced by your hand on the brake lever is enough to stop a motorcycle, engineers have achieved this by clever use of Pascal’s law. The smaller piston also fills the piston with oil so the oil is pressurized. If you examine carefully you can see that this piston is connected via a cable to a larger piston.

In short the big piston sits near the brake pads. And the small piston sits near the brake lever. According to Pascal’s law the pressure on both pistons should be the same this means the force you applied on the lever and on the brake pads will be multiplied by the difference in area of the piston. This force will move the brake pad and press it against the brake disc thus stopping the wheel as the disc is attached directly to the wheel. To further increase the area, usually 2 pistons are used on the brake pads and. Another interesting thing you can notice about this mechanism is that the pistons are only on one side then how the brake pads move on the other side. This is made possible by a clever arrangement known as the floating caliper mechanism, it should be noted that the caliber of the large part of this mechanism is not static but is free to move linearly. A caliper support is fixed to the motorcycle. You can see how the caliper moves with this fixed part.

This means that as pressure builds up in the cylinder, the floating caliper will also move opposite to the motion of the piston. The second brake shoe is attached directly to the floating caliper so the braking action will happen simultaneously on both sides. Due to the friction between the desk and the brake pads, a huge amount of heat is generated and the desk becomes extremely hot. In motorcycles the temperature of the disc can be controlled due to the circulation of air around it. In cars you need a lot of air circulation and surface area for temperature control, that’s why the discs in cars have veins, the veins will help expel the air radially outwards, the holes around the desk Will further improve air circulation. The disc brake mechanism may seem like a simple mechanism, however in order to understand how much disc brakes have helped in making automobiles safer, we must first learn about the predecessors of the disc brake drum brake. Drum brakes ruled the automobile industry for many decades, they are still used in the rear wheels of some cars they were working on, the mechanism being a fairly simple drum attached directly to the wheels when you unscrew the brake shoe pair. The friction force applied inside the drum and due to expansion comes to arrest the wheel. At first glance this seems like a simple and correct mechanism, however drum brakes tend to overheat during braking, as it is no easy task to keep them at or below optimum temperature due to the close nature of drum brakes, thus Overheating of the metal can cause expansion. drum and thus reduction in friction force. A particularly dangerous situation arises if a drum heats up due to metal breaking or shape change in this case because it does not slow down, accelerate because of the reduced frictional force, the path to tire frictional force. will also be less here on the axle than on the other wheel. These different frictional forces will create a net torque during braking and because of this the entire wheel of the car will spin. This is why you often notice that older cars that only use drum brakes will sometimes pull left or right during braking. There is no such heating problem with disc brakes. Disc brakes also have better stopping power than drum brakes.

Main Components of Disc brake

1. Wheel Hub: The disc rotor is attached to the wheel hub and rotates with it. The wheel of the vehicle is attached to the wheel hub.

2. Caliper Assembly:

The caliper assembly consists of the following tools

Brake Pad: It makes contact with rotor disc and due to friction between brake pad and rotor disc the speed of the vehicle decreases and it comes to a halt.
Caliper Bracket
caliper frame
Piston: When the brake lever is pressed, it exerts brake force on the brake pads.
Slider Pin: It is the sliding pin which slides into the hole when braking is applied.
Dust Boots: This prevents dust from entering the caliper pin or slider pin hole.

3. Disc Rotor: It is the rotating part of disc brake. When brakes are applied, a lot of heat is generated which can reduce braking efficiency, so the rotor has vent holes drilled on it which dissipate the heat.

How Disc Brakes Works

When the brake pedal is pressed, high-pressure fluid from the master cylinder pushes the piston out.
The piston pushes the brake pads against the rotating discs.
As the inner brake pad touches the rotor, the fluid pressure exerts a forward force and the caliper moves inward and pulls the outer brake pad towards the rotating disc and it touches the disc.
Now both brake pads push the rotating disc, a large amount of friction is generated between the pad and the rotating disc and slows down the vehicle and finally stops it.
When the brake pad is released, the piston moves inward, moving the brake pad away from the rotating disc. And the car starts running again.

Advantages of Disc Brakes

It is lighter than drum brakes.
It has better cooling (as the braking surface is directly exposed to the air)
It provides better resistance to slow down the sap.
It provides uniform pressure distribution
Brake pads are easy to replace.
By design, they are self-adjusting brakes.

Disadvantages of Disc Brakes

It is costlier than drum brake.
High pedal pressure is required to stop the vehicle. This brake system is fitted with a vacuum booster.
No servo action is present.
It is difficult to attach a parking attachment to a disc brake.

Where Disc Brakes is used?

Disc brakes are mostly used in motorcycles and cars.

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