02-09-2017, 02:55 PM
A disc brake is a type of brake that uses tweezers to tighten pairs of pads against a rotor (or "disc") to create friction that retards the rotation of an axle, such as a vehicle axle, either to reduce its speed of rotation or to keep it still. The energy of the movement is converted into residual heat that must be dispersed. Hydraulic disc brakes are the most common form of brake for motor vehicles, but the principles of a disc brake are applicable to almost any rotating shaft.
Compared to drum brakes, disc brakes offer better braking performance because the disc cools more easily. As a result the discs are less prone to brake fading caused when the brake components overheat. Disc brakes also recover faster from immersion (wet brakes are less effective than dry brakes).
Most drum brake designs have at least one main shoe, which gives a servo effect. In contrast, a disc brake has no self-servo effect and its braking force is always proportional to the pressure exerted on the brake system by any brake booster, brake pedal or lever. This tends to give the driver a better "feel" and helps avoid imminent blocking. Drums are also prone to "mouth bell" and trap the worn coating material inside the set, both causes of various braking problems.
The rotor is generally made of cast iron, but may in some cases be made of composite materials such as reinforced carbon-carbon matrix or ceramic matrix composites. This is connected to the wheel and / or shaft. To retard the wheel, the friction material in the form of brake pads, mounted on the brake caliper, is mechanically, hydraulically, pneumatically or electromagnetically forced against both sides of the rotor. Friction causes the rotor and the coupled wheel to slow or stop.
The development of disc brakes began in England in the 1890s, but were not practical or widely available in cars for another 60 years. The successful application began on airplanes before World War II, and even the German tiger tank was fitted with disks in 1942. After the war, technological progress began to arrive in the 1950s, leading to a critical show of the superiority in 1953 24 hours of Le Mans, which required braking of high speeds several times per lap. The Jaguar racing team won, using cars equipped with disc brakes, with much of the credit being given to superior performance brakes to rivals equipped with drum brakes. Mass production began with the 1955 Citroën DS.
Compared to drum brakes, disc brakes offer better braking performance because the disc cools more easily. As a result the discs are less prone to brake fading caused when the brake components overheat. Disc brakes also recover faster from immersion (wet brakes are less effective than dry brakes).
Most drum brake designs have at least one main shoe, which gives a servo effect. In contrast, a disc brake has no self-servo effect and its braking force is always proportional to the pressure exerted on the brake system by any brake booster, brake pedal or lever. This tends to give the driver a better "feel" and helps avoid imminent blocking. Drums are also prone to "mouth bell" and trap the worn coating material inside the set, both causes of various braking problems.
The rotor is generally made of cast iron, but may in some cases be made of composite materials such as reinforced carbon-carbon matrix or ceramic matrix composites. This is connected to the wheel and / or shaft. To retard the wheel, the friction material in the form of brake pads, mounted on the brake caliper, is mechanically, hydraulically, pneumatically or electromagnetically forced against both sides of the rotor. Friction causes the rotor and the coupled wheel to slow or stop.
The development of disc brakes began in England in the 1890s, but were not practical or widely available in cars for another 60 years. The successful application began on airplanes before World War II, and even the German tiger tank was fitted with disks in 1942. After the war, technological progress began to arrive in the 1950s, leading to a critical show of the superiority in 1953 24 hours of Le Mans, which required braking of high speeds several times per lap. The Jaguar racing team won, using cars equipped with disc brakes, with much of the credit being given to superior performance brakes to rivals equipped with drum brakes. Mass production began with the 1955 Citroën DS.