The key point: the effect of brake fluid on braking performance of wheel loaders. There are many factors that cause the failure of the loader's braking system, such as the failure of the brake components resulting in the failure of the brake. In recent years, the main reason for the rising trend of loader braking system is that the decline of the quality of brake fluid and brake disc is also one of the factors.
In recent years, the failure of the loader brake system has become a rising trend, especially a series of problems such as brake failure, braking system temperature rise, brake pump air blowhole oil and so on. At present, almost all the brake systems of domestic loaders use air top oil clamp disc brake, and the selection of brake elements is roughly the same as that of the car. There are many factors that cause the failure of the loader's braking system, such as the failure of the brake components resulting in the failure of the brake. In recent years, the main reason for the rising trend of loader braking system is that the decline of the quality of brake fluid and brake disc is also one of the influencing factors. The following is a brief introduction to the effect of brake fluid on braking performance of wheel loaders.
Two. The performance requirements of the loader for the brake fluid
(1) good viscosity and temperature properties and low temperature performance
The loader often works in the bad working environment such as mountain and mine, so the working mode of loader requires the loader to move forward and backward frequently in each working cycle, and the braking friction for a long time is in the braking state, so the friction heat can make the friction plate temperature up to 250 degrees in the braking process. The temperature of the brake fluid is given to the brake fluid, and the working temperature of the brake fluid is 70 to 90 degrees C. When the environment needs frequent braking in the mountain environment, the working temperature can reach 110 degrees C, and the temperature of the brake fluid can be reached to 150 degrees C, and the temperature of the brake fluid in the northeast and northwestern regions in winter can be lower to below -40 degrees, so the brake fluid has a good viscosity temperature. Energy and low temperature flow performance. Suitable high temperature viscosity, low freezing point and low temperature viscosity.
(2) proper lubricity
In order to keep the brake cylinder and rubber bowl sliding well, the brake fluid must be lubricated properly.
(3) ensure that the brake is safe and reliable and does not produce gas resistance
A lot of friction heat is produced when the loader runs regularly and produces a lot of friction heat, which makes the temperature of the brake system rise. For example, using the brake fluid which is low boiling point and easy to evaporate, the evaporation of the brake fluid will be filled with steam in the local brake system at high temperature, resulting in gas resistance and the brake failure. Therefore, the brake fluid should be provided with higher boiling point and lower evaporation so as to avoid the reduction of gas resistance.
(4) better anticorrosion
Brake fluid has good anticorrosion properties for various metal parts of brake.
(5) good chemical stability
The brake fluid is used for a long time under the action of high humidity, so it is required that the brake fluid do not produce thermal decomposition and overlap, and the oil can be tackled, and the sediment is not allowed to produce.
(6) good adaptability to rubber
There are many rubber seals and leather bowls in the brake system to keep the brake system completely closed, so the brake fluid should have a good adaptability to the rubber seal and prevent the rubber seal from expanding and reducing the mechanical strength because of the incompatibility of the oil.
Three. Influence on the dynamic behavior of wheel loading mechanism
(1) when the steam and gas exist in the pipe of the brake system, because the compressibility of the gas is relatively large, the brake pedal feels soft and elastic when the brake pedal is tread, which indicates that the brake fluid is infiltrated into the air, which will reduce the brake effect and reduce the braking speed. Especially in mountainous and mountainous areas, the temperature of brake fluid is increased because of frequent braking. If the boiling point of the brake fluid is low, the brake system will be more prone to cavitation erosion so as to damage the rubber seal ring and brake element of the force pump. The failure of the braking system will cause harm to personal safety. In addition, when there is gas in the brake fluid line of the brake system, when the brake pedal is loosened, the phenomenon that the expansion speed of the gas is faster than the brake fluid is sometimes produced from the brake oil cup. Low boiling point brake fluid seriously affects the braking performance of wheel loaders. At present, most of the domestic wheel loaders choose 719 synthetic brake fluid, which is equivalent to HZY3 of domestic GB12981-2003 and DOT3 of international standard. The dry boiling point of this kind of brake fluid is 205 C, the boiling point refers to the boiling point just after the brake system is added from the sealed container, and the boiling point of some low-quality movable liquid is low, thus affecting the brake safety. Full nature.
(2) the inferior brake fluid has a strong water absorption, the water vapor in the air is absorbed by the brake fluid and the rain days work to make the water into the brake fluid. After the water enters the brake fluid, the boiling point of the brake fluid will be reduced, so the anti gas resistance ability of the brake fluid is also greatly reduced. When it is used, if a lot of water is found in the brake fluid for some reason, it is necessary to replace the new brake fluid in time. When the brake fluid is updated, the brake system must be dried and the water and other oil are strictly prohibited.
Four, simple identification method of brake fluid and points for attention in use.
(1) a little brake fluid in the palm of the palm, the real brake fluid will feel some cold, and then feel some fever after a moment, and the brake fluid is not easy to volatilize: if the feeling brake fluid is cold, there is no heat feeling, and will gradually evaporate, it can be a fake brake fluid.
(2) before changing the brake fluid, it is necessary to clean up the oil and soil, such as the brake system and the liquid, and so on, so as to prevent the impurities from entering the brake system. The brake system should be cleaned according to the requirements of the maintenance manual, and the same type of brake fluid should be adopted.
(3) the brake fluid has a certain toxicity, with the mouth not to draw.
(4) coating the brake fluid to the exterior of the destructive, will have a "bite the lacquer". Therefore, in the replacement and filling of brake fluid, brake fluid to prevent dripping on the body of the coating on the surface corrosion of the loader, the mechanical rust.
(5) prohibited the use of mixed with other brake fluid. Due to the different kinds of raw materials, additives and manufacturing processes used in different kinds of products, turbidity or precipitation will appear after mixing, which will not only greatly reduce the performance of the original brake fluid, but also the precipitate particles will block the serious consequences of the brake failure. Even if it is compatible with one type of brake fluid is better, if the brand is different, also do not mix. Because the phase solubility is good, it is only indicated that there is no stratification, turbidity and precipitation after mixing with other products. It does not mean that the performance after mixing is not constant. The additives added in each product are different and have relative equilibrium. Once mixed with other substances, the balance will be destroyed and thus lost or reduced. The proper role. Therefore, the replacement of the brand must be used when cleaning products to be added the line. [--empirenews.page--]!
The dynamic fluid of wheel loading mechanism is an important medium for the transmission power of the loader brake system. It is the main factor related to the braking safety of the wheel loader. Due to the influence of some counterfeit brake fluid in recent years, the braking performance of the automobile and wheel type engineering machinery is reduced, and the safety of the body is threatened. It should cause the wheel loader to make it. With the attention.