Brake pads are a part of disc used in automotive and other applications. Brake pads are steel backing plates with friction material bonded to the surface that the disc brake rotor.
Brake Pads – Function
Brake pads convert the kinetic energy of the vehicle to thermal energy through friction. Two pads are included in the caliper with their friction surfaces facing the rotor. When the hydraulic brakes are applied, the caliper clamps or squeezes the two pads together in the spinning rotor to slow / stop the car. If a brake pad is heated by contact with a rotor, gives the small amounts of friction material rotate the disk gray. The brake pad and disc (both now with friction material) and “stick” to each other, causing friction that the vehicle stops.
In disc brake applications, there are usually two brake pads each rotor disc, held in place and operated by a thickness, mounted on a wheel hub or suspension upright. Although almost all road vehicles have only two brake pads per caliper, racing calipers using six pads, with different frictional properties in a staggered pattern for best performance. Depending on the properties of the material can vary disc wear and tear. The brake pads must usually be replaced regularly (depending on the path of material) and most have a system to warn the driver when this should occur. Some have a thin piece of soft metal that causes the brakes to squeal when the pads are too thin, while others have a soft metal tab embedded in the pad material that closes an electric circuit and lights a lamp when the pads are thin. More expensive cars may use an electronic sensor.
Brake Pads – Technology
Advantages of disc brakes
These brakes are better stopping performance than comparable drum brakes, including resistance to “fading” caused by the overheating of brake components, and are able to recover quickly from immersion (wet brakes are less effective).Unlike a drum brake disc not own servo effect the braking force is always proportional to the pressure on the brake pedal or lever but many disc brake systems ratification (“brake booster”) to reduce the driver’s pedal effort.
Brake Pads – Types
There are many types of brake pads, depending on the intended use of the vehicle, very soft and aggressive (like racing applications) and harder more durable and less aggressive compounds. Most car manufacturers recommend a specific type of brake pad for their vehicle, but connections can be changed (either by buying a different brand of pad or upgrading to a performance path within range of a manufacturer) based on personal taste and driving style. There must always be taken into account when installing non-standard brake pads, as operating temperature range can vary, such as performance pads not braking efficiently when cold or standard pads fading under hard driving. In cars that suffer from excessive fading, the problem can be minimized by installing better quality and more aggressive brake pads.
Brake Pads – Materials
Brake materials ranging from asbestos to organic or semi-metallic formulations.Each of these materials has proven advantages and disadvantages regarding environmental friendliness, wear, noise, stop and powerful. Semi-metallic pads provide the strength and heat away from rotors, but also noise and are abrasive enough to increase rotor wear.
Ceramic fibers and copper compounds in place of steel, the semi-metal path of the fibers suitable for higher temperatures with less heat disappears and generating less dust and wear on both the pads and rotors. They also provide much quieter running through the ceramic composition which dampen noise by shifting the resonance frequency above the human hearing range and use less metal (about 15% metal content).
There are environmental factors that govern selection of brake materials. Thus, the recent legislation in Washington State (SSB 6557) and other countries limit the amount of copper may be used in friction materials, to eventually be reduced to sums to detect. Other materials such as antimony compounds will also be controlled.
Asbestos widely used in electrodes for the heat resistance, but because of the health risks has been replaced by other materials such as mineral wool, cellulose, aramid, PAN, chopped glass, steel and brass fibers. Depending on the properties of the material, the disc wear vary. The properties that determine material wear involve trade-offs between performance and longevity. Newer pads can be exotic materials such as ceramics, aramid and other plastics.
Vehicles different braking systems. Friction materials offer application-specific formulas and designs. Brake pads with a higher coefficient of friction provide good braking with less pedal pressure requirement, but tend to lose efficiency at higher temperatures, helping reduce stopping distances. Brake pad with a small and constant coefficient of friction does not lose efficiency at higher temperatures and is stable, but a higher brake pressure.