Understanding Your Car - Disc Brakes

Driving is a very complex process. It requires a lot of a concentration, coordination, situational awareness, swift decision making. Braking is one of the most crucial elements of driving. The brakes help control the speed of the car by slowing the car down, either to the desired speed or to a complete stop. The brakes are present on both the front and rear brakes of the car. There are two types of brakes which are generally used in cars – drum brakes and disc brakes. We will be telling you more about disc brakes, read on to find out more!

The development of disc brakes started in the 1890s, but it was Frederick Lanchester who developed the first patented disc brakes in 1902. The Lanchester cars were the first ones to have these brakes. French car giant Citroen was the first car manufacturer in the world to use disc brakes in a mass-production car - the Citroen DS. The DS used disc brakes at the front and was amongst the many innovations of the car at the time. Citroen sold over 1.5 million units of the DS with the same brake set-up over the course of 20 years in production. Modern cars have disc brakes set up either on the front wheels or on all wheels of the car. Disc brakes are very crucial in stopping or reducing the speed of the car. A disc brake is made up of the following parts –

 

• Rotor: The rotor is a circular disc which is bolted onto the wheel and spins along with it. Steel or cast iron are the most common materials used to produce rotors. High-end, high-performance cars use carbon ceramics to make rotors. While braking a lot of heat is produced on the rotor surface to combat this, the rotor discs are given ventilation by way of drilling holes on them for effective cooling and distribution of wasted heat. 
• Brake Pads: Brake pads push into the rotor and create friction which slows down or stops the car. The brake pads contain a metal portion called the shoe; the shoe contains a lining that comes in contact with the rotor.  The brake lining wears away over time with use.    
• Piston: The piston is a cylinder which is connected to the hydraulic fluid system of the brake. The piston moves the brake pads into the rotor when the driver presses the brake pedal.
• Caliper: A caliper is a case that fits over the rotor and holds the brake pads, piston into position. The caliper also contains the duct for the hydraulic brake fluid. There are two types of calipers – floating and fixed.

The brake pedal is connected to the brake master cylinder. When the driver presses the brake pedal the piston inside the master cylinder pressurizes the hydraulic fluid in the brake lines moving the pistons and pushing the brake pads into the rotor. The harder the driver pushes the brake pedal the harder the brake pad will squeeze against the rotor, hence applying more braking force. The brake pads move only a few millimeters and retract back into the calipers as soon as the drivers lift the foot off the pedal. Disc brake systems go through a lot of wear and tear. Even during normal driving conditions, there is a lot of heat that is generated while braking and this tends to take a toll on the brakes. Periodic maintenance is required to change the brake fluid, brake pads etc.

Disc brakes are a very crucial part of the car and can often come to the rescue in emergency situations. Disc brakes are also used in various other modes of transportation such as motorbikes, airplanes, trains, etc. and they continue to remain one of the most important inventions not only for cars but other automobiles, modes of transportation as well.