In a general passenger car, the front and rear wheel braking device is often not the same. If all four disc brakes, front disc brake ventilated multi-use, the rear disc brake plurality ordinary. If the disc is mixed with drum brakes, disc brakes front wheels, the rear drum brake employed.
1. The front and rear wheel brake type noun
at the time of braking, the contribution of the front wheel brake percentage to the vehicle 85, far more than the contribution of the rear wheel brake. And a drum front brake disc is generally divided into two kinds. In a general passenger car, the front and rear wheel braking device is often not the same. If all four disc brakes, front disc brake ventilated multi-use, the rear disc brake plurality ordinary. If the disc is mixed with drum brakes, disc brakes front wheels, the rear drum brake employed.
2. The drum brake
The drum brake, also known as brake blocks, brake pads are pressed against the brake wheel brakes to achieve. Drum brake is an early design of the braking system, brake drum design that has been used in 1902 on the carriage, until around 1920 began widely used in the automotive industry. It is now the mainstream of the drum brake type sheets, which brake shoe (brake shoe) located inner wheel braking, when the brake pad braking outwardly flared, inner friction wheel brake, braking purposes. Nearly three decades, the drum brakes on the car in the field has given way to gradually withdraw disc brakes. However, due to relatively low cost, is still used in some cars in the economy class, mainly used for braking the rear wheel load is relatively small and the parking brake.
Usually a car rear drum brakes (front wheel disc brakes). In addition to relatively low cost drum brakes addition, there is an added benefit of parking (parking) brake together in combination with, any rear drum brakes for the car, its parking brake on the rear wheel brake combination . This is a mechanical system, which hydraulic brake system of the vehicle completely separate: the use of a hand lever or the parking pedal tensioned steel cable (American car), drum brake actuating lever member of the brake shoe expansion, from to the parking braking action, so that the car does not slip movement; release steel cables, brake shoe return spring back into place, the braking force disappears.
The drum brake advantages
Drum brakes are inexpensive, and consistent with conventional design. Four cars during braking, due to inertia, the load wheel 70 is generally a percentage of the full load -80 percentage cars, large front wheel braking force than the rear wheels, the rear brake play a supporting role, and therefore the car manufacturers to save costs, to use the brake Qianpanhougu embodiment. But for heavy vehicles, because the speed is generally not very high, the durability of the brake shoes is also higher than disc brakes, so many heavyFour-wheel vehicles still drum design.
The drum brake disadvantages
Many, braking efficiency and heat dissipation difference drum brakes have braking force difference in the stability of the drum brake, on different road surface braking force big changes and difficult to control. And due to poor heat radiation performance, during braking will gather a large amount of heat. Brake shoe and the drum at extremely high temperatures are more prone to deformation complex, prone to vibration and shaking brake fading phenomenon, causing decreased braking efficiency. In addition, drum brakes in use for some time, to regularly adjust the brake shoe clearance, and even split out to involve the entire brake drum brakes, including cleaning up the accumulated dust.
3. The disc brake
Since the vehicle traveling speed increasing performance, to increase the stability of the vehicle at high speed brakes, disc brakes It has become the mainstream of the current brake system. Disc brakes, also known as disc brakes. It is generally manufactured by the hydraulic control of a steel alloy and fixed to the wheel rotates with the wheel. The disc brake according to the material structure can be divided into ordinary disc, ventilated disc and ceramic disc. The main parts of the brake disc, cylinder, brake caliper, tubing and the like. Disc brake fast heat, light weight, simple structure, easy to adjust. Especially when high load high temperature performance, braking effect is stable, but also not afraid of mud invasion, ideal for driving in the winter and bad road conditions.
works
is stationary disc brake brake disc, with the rotation of the tire sandwiching the brake disc to generate a frictional forceThe brake wheel rotation speed reduction. When the brake pedal, the piston is pushed in the brake master cylinder, the brake pressure is established in the oil passage. The brake caliper pressure is transmitted to the piston via a brake fluid, a piston in the brake wheel cylinder under pressure, moves outward and pushes the brake pads to clamp the brake disc, brake pads and the brake disc so that the friction occurring, in order to reduce the rotational speed of the wheel, make the car slow down or stop. Advantage
of the disc brake
1. General co frictionless action potential, little influence braking efficiency coefficient of friction stability;
2 good water stability, braking performance after immersion in water decreased smaller and faster recovery;..
in the same braking force 3 in the case of smaller size by weight;.
after the brake disk 4 is small axial expansion heat, without too much influence stopper gap;
5 easy to achieve automatic adjustment of the gap. ;
6 small axial dimension of the brake disc, is arranged in front to facilitate.
disc brake disadvantages:
1 low braking efficiency, requiring relatively high line pressure;
2 also serves as a when the parking brake, it is necessary to install a complicated transmission, when used on the rear wheels is limited. .
3 is difficult to avoid dust pollution and corrosion
4 disadvantage disc brake of: automatically because there is no evil effect of tightening a drum brake, braking force that the brake disc than drum brakes low.
5. Greater wear of the brake pads, causing the frequency of replacement may be higher.
ventilated discs
ventilated brake disc is hollow interior, car in which cool air can exercise through the middle, so that air convection cooling purposes. From the outside, it has many holes leading to the empty center, these are empty holes through a special process (slotteded amp; drilled) in the circumferential manufactured, many cooling effect than ordinary disc. Because of the manufacturing process and the cost of the general class cars commonly used in ventilation agoDisc, the disc brake pad normal. Section limousine ventilated discs front and rear. And most economical car using Qianpanhougu brake (brake). Due to security requirements and the cost of the vehicle down at the front wheel ventilated disc use is gradually replacing the use of solid discs.
Ceramic plate
is not an ordinary ceramic brakes ceramics, carbon fibers and silicon carbide synthesis but at a temperature of 1700 degrees reinforced composite ceramics. Only half of the weight of the ceramic disk plate is less than ordinary cast iron, for example, ceramic brake SLR MCIAREB, which brakes the front wheel diameter is 370mm, but weighs only 6.4 kg. While the ordinary brakes of the CL-CLASS front plate having a diameter of up to 360mm but the weight of 15.4 kg.
means lighter brakes reduce the weight of the suspension. This makes the reaction suspension system faster and thus can improve the overall level of control of the vehicle. Further, Common brake discs easily generated due to heat at the full brake thermal recession, ceramic brakes can be effectively stabilized against decay heat, the heat effect is many times higher than normal brakes, and, in a ceramic dish braking initial stage immediately generate the maximum braking force, so that even without increasing the brake assist system, and the overall braking faster, shorter distance than a conventional braking system, in order to resist heat, the brake pad between the brake piston and ceramic to heat insulation, ceramic brake discs have exceptional durability, if normal use lifetime free replacement of cast iron brake discs and ordinary general spend a few years to be replaced.
4. Introduction ventilated discs
Internal
ventilated brake disc is hollow and cooling air may pass from the car in the middle of the exercise which the air convection cooling purposes. From the outside, it has many holes leading to the empty center, these are empty holes through a special process (slotteded amp; drilled) in the circumferential manufactured, many cooling effect than ordinary disc. Since the relationship between the manufacturing process and cost, commonly used in the general class cars front ventilated discs, the disc brake pad normal. Section limousine ventilated discs front and rear. And most economical car using Qianpanhougu brake (brake). Due to security requirements and the cost of the vehicle down at the front wheel ventilated disc use is gradually replacing the use of solid discs.
5. The ceramic disc
is not common porcelain ceramic brakes, but carbon fiber reinforced silicon carbide composite ceramic synthesized at a high temperature of 1700. Only half of the weight of the ceramic disk plate is less than ordinary cast iron, for example, ceramic brake SLR MCIAREB, which brakes the front wheel diameter is 370mm, but weighs only 6.4 kg. While the ordinary brakes of the CL-CLASS front plate having a diameter of up to 360mm but the weight of 15.4 kg.
means lighter brakes reduce the weight of the suspension. This makes the reaction suspension system faster and thus can improve the overall level of control of the vehicle. Further, Common brake discs easily generated due to heat at the full brake thermal recession, ceramic brakes can be effectively stabilized against decay heat, the heat efficiencyIf many times higher than normal brakes, as well as ceramic dish immediately be able to produce the maximum braking force in initial braking stage, even without brake assist system increases, and the overall braking faster than conventional braking systems, from more is short, resistance to heat, between the brake piston and brake pad for a ceramic insulation, ceramic brake discs have exceptional durability, if free replacement lifetime normal use, and ordinary cast iron brake discs typically spend several years to be replaced.