The braking performance of wheel loader is an important parameter to evaluate the safety performance of wheel loader. Generally speaking, the shorter the braking distance, the safer it is. Parts of wheel loader involved in braking include:air booster pump、Air Brake booster、air brake valve、oil-water separation combined valve for loader、unloading valve for loader、Loader quick release valve。
At present, the commonly used method to evaluate the vehicle braking distance in the automobile industry is the braking distance from emergency braking to static braking when the speed is 100 kilometers. So what factors, other than the well-known speed, affect braking distance?
In fact, braking distance is also restricted by many complex factors. Mainly braking force and vehicle weight. Braking force refers to the friction between the brake pad and the brake disc and the friction between the tire and the ground. The friction between the brake pad and the brake disc is the brake strength in the general sense, which is mainly determined by the material of the brake pad and the brake disc. At present, disc brakes are widely used in the automobile market. The reason is that disc braking systems can dissipate the heat generated by friction during braking. If friction heat is not effectively distributed, the braking strength will be weakened, and even lead to brake failure. So,
The friction between the tire and the ground is static friction when it is not locked, and sliding friction when it is locked. Although sliding friction is related to the weight of the vehicle and the material of the tire, static friction is generally greater than sliding friction. Which brings us to a topic of current concern in the auto industry: "brake lock." Because the static friction force in the braking process is greater than the sliding friction force, so if the tire is not locked in the braking process, you can achieve the best braking effect.
Therefore, the braking anti-lock braking system "ABS" came into being. The role of ABS is to release the brake when the vehicle is about to be locked, so that the braking force is basically static friction force. If properly tuned, ABS can maintain a higher braking force than sliding friction, which means that in this ideal situation, braking distances can be shorter than in models without ABS. Therefore, the braking assistance system of the vehicle, especially the configuration of ABS system, is also a key factor affecting the braking distance.
In addition, many people believe that the longer the vehicle, the longer the braking distance. In fact, this view is one-sided. Because under road conditions, the sliding friction force of the vehicle brake is proportional to the weight of the vehicle. In other words, the heavier the vehicle, the greater the sliding friction. Although ABS models use static friction during braking, the increase of sliding friction also increases the critical friction of static friction. In this way, more static friction braking force can be obtained for the vehicle. So, it's not that the lighter the brakes, the better.
Two, the reasonable use of safety brake distance, although the brake distance is related to many complex factors, but for the majority of car owners, regular maintenance of the car, to ensure that the car is in good condition is to ensure the premise of daily driving safety brake. For example, brake pads should be replaced regularly, and worn brake pads will greatly reduce the braking effect. If the tire is seriously worn, it should be replaced in time. Although the vehicle is equipped with an auxiliary braking system such as ABS, the braking performance of the vehicle can be reduced if the brake pads and tires are in poor condition.
It should be noted that, even if maintained in good condition, the brake must be kept at a sufficient brake distance, the front brake light is on, and the right foot must be placed on the brake pedal. Many car owners prefer to stay close to the car in front of them and brake when the car in front slows down. In fact, this habit is not safe. If you are driving normally within 20 meters of the vehicle in front and the brake light is on, you must prepare to brake immediately. You must keep a distance of 20 meters from the vehicle in front of you at all times during braking. Make sure the vehicle is stopped before gradually reducing the distance. Don't think it's too far to take action, because sometimes when you feel in danger,
Many rear-end collisions are caused by owners being overconfident about the braking distance of their vehicles. After all, braking distance is not only a vehicle factor, but also driver reaction and other human factors. So try to keep a safe distance and drive carefully is the safe way.
Common air brake braking system is composed of brake control mechanism, double circuit braking mechanism, brake, air compressor and other components, including brake control mechanism brake pedal, pedal suspension, manual brake valve, etc. ; The double circuit brake mechanism includes gas storage tank, brake valve, low pressure alarm, pressure regulator, brake pipe, reversing valve, relay valve, safety valve and discharge valve. 2. Working principle, because the braking principle of the air brake power system is the same as that of the ordinary air brake. Here we will focus on the working principle of the parking brake. Firstly, the structure of the gas chamber of the energy storage spring is described. The energy storage spring air chamber is the shell of the service brake air chamber. The hole is communicated with the parallel brake chamber of the ventilation joint port of the parking brake chamber. The piston assembly of the service brake chamber is composed of a piston body, a dense earth cover ring and a guide sleeve. In parking braking, the push rod only pushes the piston, while in service braking, the piston does not move. Before starting the car, the lever of the manual valve should be pulled back to release the parking brake position so that compressed air from the parking brake reservoir fills the parking brake chamber. Compression of the energy storage spring returns the parked piston to the non-braking position. At the same time, the service brake piston is also returned by the reset spring. The parking brake is released and the vehicle can start, but if the air pressure in the tank does not reach the minimum safe value, the spring cannot be compressed, so the car cannot start. This is the main advantage of parking brakes with energy storage springs. When the driver operates the manual brake valve, the core tube is taut in a spring. By operating the CAM, the inlet valve is closed, the exhaust valve is opened, and the air outlet is led to the atmosphere through the core pipe and the exhaust port. The energy storage brake chamber in the composite brake chamber is also discharged into the atmosphere through the quick release valve. The vehicle is in the parking brake. The maximum travel of the parking brake chamber is generally 10% larger. Therefore, when the service brake push rod has moved to its maximum stroke,
What's the difference between an air brake and an oil brake? Often, first-time buyers ask us this question. Many customers ask us to provide the multi-function sprinkler or van with airlock they want to buy. The airlock has an oil brake. What are the advantages?
Let's talk about the difference between these two braking methods.
1. The oil brake has simple structure and small installation space. It only needs to brake the master pump, pump, oil cup and connection line. No other auxiliary equipment is required; Air brake is more complex, in addition to the master cylinder, cylinder, brake line, there are air pump (connected to the engine through the belt), gas storage tank, high pressure controller (adjust the pressure, the car can be 8 atmospheres), relay valve and other components, installation space is large, complex structure. And to ensure safety, the rear brake cylinder is now air-brake (cost increased, structure complex).
2. The response speed of the oil brake is slightly slow, the brake is soft and the force is small; Air brake response is fast, brake coarse, force (high pressure, up to 8 atmospheres).
Therefore, for these reasons, most oil brakes are small and medium trucks. They are small, simple, light in their own vehicles and do not require much effort. In recent years, there has been a trend of mid-size cars (carrying capacity below 10 tons, some mid-size buses below 19 are equipped with oil brakes. Air brake is mostly used in large trucks, heavy trucks on the road wrecker and powder material removal vehicle, vehicle space, braking force, the use of distance, reaction speed to fast, the increased cost is reflected in the vehicle accounted for a small proportion.
3. The parking brake is fundamentally different. The former is a central disc brake, which is a human type, and the latter is an energy storage spring air brake, which is a power type.
4. The parking brake of ordinary air brake can only be used when the truck is stationary, because the braking torque acts on the drive shaft. If used in a small compression garbage truck, it is easy to cause the drive shaft and rear. The serious overload of the bridge may also be due to the locking of the differential box and the rotation inversion of the left and right wheels, leading to the deviation or even the U-turn of the truck when braking. However, the energy storage spring braking is different. On the contrary, because the parking braking travel of the energy storage spring is longer than the driving braking travel, the energy storage spring can be used to brake in the case of insufficient braking force. Assist in emergency braking. Therefore, the energy storage spring brake can be used not only as a parking brake, but also as an emergency brake. Therefore, the air braking system is superior to the traditional air braking system in braking stability and safety.
5. There is a strong spring in the air brake chamber. Compressed air lifts the spring while driving. The handbrake is to deflate and let the spring lock the brake. When the pressure in the car is too low, it will also produce braking effect to ensure safety.
6. The conventional brake is the handbrake that locks the transmission shaft. When the foot brake is pressed, compressed air enters the brake cavity and locks the wheels. When the hand brake or transmission shaft mechanical failure, the hand brake failure; A foot brake fails when any part of an air pump, pipe, tank, or brake valve fails. Through the above comparison, air braking can effectively avoid these dangers. We know the difference between these two types of braking.
Conclusion:
The characteristics of the oil brake: the brake distance is long, the response is slow, but the structure is simple, the maintenance is convenient, the oil brake price is cheap, mainly used for small trucks and motorcycles, but now the air brake is the trend of The Times, some small trucks have begun to be equipped with air brake. The main reason is that customers need brake brakes to ensure truck safety. The characteristics of air brake: short braking distance, fast response speed, complex structure, high maintenance cost, high procurement cost, suitable for medium and large truck, bus, semi trailer, concrete mixing truck and other heavy vehicles,
Air brake and ordinary air brake is very different, each has its own advantages. If you choose to install the ordinary air brake on the large heavy road wrecker, it will appear some "inadequate". The differences between air brake and ordinary air brake are as follows: 1. Parking brake is fundamentally different. The gas brake is the energy storage spring gas brake, which belongs to the power type, and the ordinary gas brake is the central disc brake, which belongs to the human type. The power supply devices are completely different. 2. The parking brake of ordinary air brake can only be used when the car is stationary, because the braking torque acts on the drive shaft. If used while the car is moving, the drive shaft and rear axle can easily cause serious overtaking. May also be due to the differential box locked, left and right wheels in the opposite direction, resulting in the car in the brake dislocation or even turn around. However, the energy storage spring braking is different. On the contrary, because the parking braking travel of the energy storage spring is longer than the driving braking travel, the energy storage spring can be used to brake in the case of insufficient braking force. Assist in emergency braking. Therefore, the energy storage spring brake can be used not only as a parking brake, but also as an emergency brake. Therefore, the air braking system is superior to the traditional air braking system in braking stability and safety. Causing the car to misposition or even turn around when braking. However, the energy storage spring braking is different. On the contrary, because the parking braking travel of the energy storage spring is longer than the driving braking travel, the energy storage spring can be used to brake in the case of insufficient braking force. Assist in emergency braking. Therefore, the energy storage spring brake can be used not only as a parking brake, but also as an emergency brake. Therefore, the air braking system is superior to the traditional air braking system in braking stability and safety. Causing the car to misposition or even turn around when braking. However, the energy storage spring braking is different. On the contrary, because the parking braking travel of the energy storage spring is longer than the driving braking travel, the energy storage spring can be used to brake in the case of insufficient braking force. Assist in emergency braking. Therefore, the energy storage spring brake can be used not only as a parking brake, but also as an emergency brake. Therefore, the air braking system is superior to the traditional air braking system in braking stability and safety. Energy storage springs can be used to assist emergency braking. Therefore, the energy storage spring brake can be used not only as a parking brake, but also as an emergency brake. Therefore, the air braking system is superior to the traditional air braking system in braking stability and safety. Energy storage springs can be used to assist emergency braking. Therefore, the energy storage spring brake can be used not only as a parking brake, but also as an emergency brake. Therefore, the air braking system is superior to the traditional air braking system in braking stability and safety.
The air brake is mostly used in the hand brake system of heavy duty road wrecker or other special vehicles. The handbrake system of this type of car usually uses a strong spring in the normal braking state. When the vehicle is driving, the driver releases the handbrake to deflate the action, must reach a certain pressure to open the spring, that is, the hand lost to drive.
The conventional brake of a Xigong Chusheng car is a handbrake that locks the transmission shaft. When the foot brake is deactivated, compressed air enters the brake chamber to lock the wheels. When the hand brake or transmission shaft mechanical failure, the hand brake failure; A foot brake fails when any part of an air pump, pipe, tank, or brake valve fails. Broken brakes can effectively avoid these dangers.
