Brake pads are disc brake components used in automotive and other applications. The brake pad is a steel retaining plate with a friction material bonded to the surface facing the disc brake rotor.
Video Brake pad
Function
The brake pads convert the kinetic energy of the vehicle into heat energy through friction. Two brake pads are contained in brake calipers, with their friction surfaces facing the rotor. When the brakes are applied hydraulically, the caliper clamps or squeeze the two pads together to the rotating rotor to slow/stop the vehicle. When the brake pad heats up due to contact with the rotor, it transfers a small amount of friction material to the disc, leaving a dull gray layer on it. Rem pads and disks (both now have friction material), then "stick" to each other, giving friction that stops the vehicle.
In disc brakes, there are usually two brake pads per disk rotor. It is held in place and driven by a caliper affixed to the wheel hub or upright suspension. Most vehicles have two brake pads per caliper. But racing calipers can utilize up to six bearings, with varying friction properties in a staggered pattern for optimum performance. Depending on material properties, disc wear rates may vary. Brake pads usually have to be replaced regularly (depending on the pad material) to prevent the brakes from fading. Most brake pads are equipped with a method of alerting the driver when this needs to be done. A common technique is to make a small groove in the middle that is finally lost due to wear and tear indicating the end of life of a pad. Other methods include placing thin strips of soft metal in the grooves, so that when exposed (due to wear and tear) the brakes scream sound and embed a soft metal tab in the pad material that shuts off the electrical circuit and turns on the dash warning lights when the brake lining is thin.
Maps Brake pad
Technology
Advantages of disc brakes
Disc brakes offer better stopping performance compared to drum brakes. They provide better resistance to "brake fading" caused by overheating of the brake pads, and can also recover quickly from submersion (less effective wet brakes). Unlike drum brakes, disc brakes do not have a self-servo effect - the braking force is always proportional to the pressure applied to the braking pedal levers. However many disc brake systems have servo assistance ("Brake Booster") to reduce the driver pedal effort.
Type
There are many types of brake pads, depending on the purpose of vehicle use, from very soft and aggressive (like racing apps) to harder, more durable and less aggressive compounds. Most vehicle manufacturers recommend a special type of brake lining for their vehicles, but compounds can be changed (either by purchasing different bearings or upgrading to a performance pad within the manufacturer's range) according to personal taste and driving style. Care should always be taken when purchasing non-standard brake pads because the operating temperature range can vary, as performance pads do not brake efficiently when cushioned or standard pads fade under the hard drive. In cars that experience excessive brakes, problems can be minimized by installing better quality brakes and more aggressive.
Materials
The five most important characteristics to be considered when choosing a brake pad material are the following:
- The material's ability to hold the brakes fades
- The water effect on the brakes fades (all brakes are designed to hold at least temporary exposure to water)
- Ability to recover quickly from either temperature or humidity increase
- The service life that is traded by means of the rotor
- The ability of the material to provide smooth and even contact with the rotor or drum (not a material that breaks in pieces or causes a hole or dent).
For many years asbestos is immediately seen as having optimal performance in all five categories. However, since serious health-related asbestos hazards become apparent, other ingredients must be found. Today, brake lining materials are classified into one of four main categories, as follows:
- Non-metallic materials - these are made from a combination of various synthetic substances attached to composites, especially in the form of cellulose, aramid, PAN, and sintered glass. They are soft in the rotor, but produce enough dust, so have a short service life.
- Semi-metal - synthetic materials are mixed with various flattened metal proportions. It's harder than non-metallic bearings, more fade resistant and more durable, but at the increased cost of wear to the rotor/drum which should then be replaced more quickly. They also require more driving force than non-metallic bearings to produce braking torque.
- Fully metal - these pads are only used in racing vehicles, and are composed of sintered steel without synthetic additives. They are very durable, but require more power to slow down the vehicle while using the rotor faster. They also tend to be very loud.
- Ceramic materials - Composed of clay and porcelain tied to copper and filament flakes, this is a good compromise between metal bearing resistance, clutches and fade resistance of various synthetics. Their main drawback, however, is that unlike the previous three types, despite the presence of copper (which has high thermal conductivity), ceramic bearings generally do not dissipate heat well, which can ultimately lead to bearings or other components of braking. system for warp. However, because ceramic materials cause the sound of braking to increase beyond human hearing, they are very quiet.
Phenol formaldehyde resins are often used as a binding agent. Graphite can act as a friction material as well as a bonding agent. An Italian manufacturer did research to use cement as a cheap and less energy-intensive binder.
There are environmental factors that govern the selection of brake pads. For example, the SSB 6557 bill adopted in Washington State in 2010 will limit the amount of copper allowed to be used in friction materials, to be eventually removed to trace amounts, due to the negative impact of high copper rates on aquatic life.. For substitutions, different material combinations have been developed, although no direct replacement has been made available. Other materials, such as compounds made with antimony, are being studied.
Vehicles have different braking requirements. Friction materials offer formulas and application-specific designs. Brake pads with higher friction coefficient provide good braking with less brake pedal pressure requirements, but tend to lose efficiency at higher temperatures. Brake pads with smaller and constant friction coefficients do not lose efficiency at higher and stable temperatures, but require higher brake pedal pressure.
Cataloging
There are different systems for brake pads catalog. The most commonly used system in Europe is the WVA numbering system.
The cataloging system used in North America, and recognized worldwide, is a standard part numbering system for brake and clutch surfaces issued by the Friction Materials Standards Institute (FMSI). The mission of FMSI is, "Maintain and upgrade this standardized part numbering system for all highway vehicles used in North America."
Cartridge brake pad
The type of brake lining that is used on the rim brake.
See also
- Brake layer
- Brake Shoes
- Brake wear indicator
References
Source of the article : Wikipedia
0 Comments