Classification of brake pads
Brakes, we refer to as the brake racing shoes or brake pads, although the volume is very small, but for the last few meters, the brake pads can also be referred to as active safety systems in the most basic and most important easy to The loss of parts, the manufacturers in order to develop the brake pads move enough of the brain, when we choose also not be taken lightly.
The brake works mainly from the friction brake pads and brake discs (drums) and the friction of the tire and the ground converted into the kinetic energy of the vehicle moving after the heat of friction to stop the car. A good efficiency of the braking system must be able to provide a stable, sufficient braking force control, and hydraulic transmission and cooling capacity to ensure that the force applied by the driver from the brake pedal fully and effectively reached the master cylinder and the wheel cylinder, and avoid high fever caused by hydraulic failure and brake recession.
The brake system on the car is divided into two major categories of disc and drum, but in addition to cost advantages, the efficiency of drum brakes is far smaller than the disc brakes. Different materials, brake pads generally can be divided into the asbestos type and semi-metallic and non-asbestos organic type of three:
1 / asbestos brake pads -
Asbestos brake pads in the past is common in drum brakes, because asbestos fibers is characterized by the features of high strength and high temperature up to 316 ° C, so to meet the brake sheets and clutch disc and liner, and it is very cheap, refined its ore rich in natural resources.
But why asbestos brake pads have disappeared? In recent years, it was discovered that asbestos has the potential hazards of asbestos by the medical profession proved to be a carcinogen, its needle-like fibers into the lungs and stay there, causing stimulation, could eventually lead to lung cancer, but this disease The incubation period can be up to 15-30 years.
Of course, asbestos brake pads, there is an important defect so that people in favor of the development of new materials to replace it. Asbestos itself particularly poor insulation, thermal capacity, so after repeated brake the brake emphasis on the accumulation of huge amounts of heat, and then will give rise to serious thermal decay we often say, or even brake failure. This phenomenon is not so obvious for the city driving, but often run high-speed vehicles, is fatal.
2 / semi-metallic mixture brake pads -
When the vehicle manufacturers and brake suppliers of materials decided to develop new, more secure asbestos-type brake pads alternatives, then the following we will talk of two new friction material, first half metal mixture material brake pads, brake the vehicle a few, the key or the price is cheap and wear.
"Semi-metal brake pads of the mixture using coarse steel wool to use as a reinforcement fiber as well as an important mixture. Appearance, we can see very fine steel wool fiber and particle structure, which allows to distinguish between the brake pads fairly easy. And because of the different materials, semi-metallic mixture of brake pads with better temperature control ability than asbestos brake pads, can withstand the higher temperature of the brake at the same time also more durable.
"Semi-metal brake pads of the mixture itself is difficult to avoid the weaknesses, the intensity due to the high internal metal content of the brake pads, brake friction relative asbestos brake pads smaller vehicles require higher braking force to accomplish the same braking effect. Contact with metal brakes and brake pads in the iron touch the iron brake, will bring more noise and wear.
In addition, there is a problem can not be ignored is that too strong a mixture of the semi-metallic brake pads heat capacity, making it able to withstand the higher temperature of the brake, but they pass out of the temperature will be delivered to the brake calipers and other metal components, resulting in brake fluid to accelerate heat to boiling to reduce the effect of the brake, brake calipers, piston ring and the return spring will accelerate aging.
Speaking of which, we already know the characteristics of the two brake pads, the ultimate solution to the materials, environmental protection, heat exhaustion, noise and wear of the brake pads, the NAO, brake pads were put on the agenda. This material brake pads use of glass fiber, aromatic polyester fibers and other fibers as a reinforcing material such as carbon or ceramic.
From the difference of material, asbestos brake pads need only 5-7 basic mixture can NAO brake pads in order to achieve the same effect, you need more mixture as an alternative to the use of the material to achieve even more than as much as 17 kinds, including glass fiber, carbon, ceramic, etc. we know, of course, it is difficult to fall to the level of "semi-metal" mixture of brake pads of manufacturing costs.
|
