Bathtub Shower,Outdoor Shower Faucet,Floor Mixer,Bathtub Faucet Geagle Intelligent Sanitary Wares Co., Ltd. , http://www.zhanying-china.com
In the mid-1990s in Europe, air disc brake ADB (Air Disc Brake) was used on a large scale in the field of commercial vehicles. Compared with the drum brake, the disc brake has the advantages of rapid heat dissipation, light weight, simple structure, and convenient adjustment. Especially when the load is high, the brake has high temperature resistance, stable braking effect, and high thermal stability.
In China, disc brakes are used more and more widely in cars, light cars, trucks, luxury passenger cars and heavy-duty trucks. With the improvement of China's highway traffic conditions, the rapid development of (high-speed) highways and the continuous improvement of vehicle performance and speed have resulted in people pursuing faster and more comfortable travel modes. The disc brake can improve the active safety of the car, and also can solve the problem that the drum brake can not solve the problem of dust pollution, brake noise pollution, frequent maintenance during the braking process, and the application in the automobile must be more extensive. .
â— Principle of disc brake The disc brake is mainly composed of brake disc, cylinder (brake chamber), brake caliper, oil (gas) pipe and other components, and liquid (gas) pressure as power source. The disc brake is friction (face) with the end face of a rotating working disc (metal disc). The friction bracket (material) (2-4 friction plates on the working surface) and its metal are mounted on the fixing bracket. The brakes (plates) of the base plate, these brakes (plates) and their tensioning devices are mounted in clamp jaws spanning the sides of the brake disc, called brake calipers.
The brake discs are made of cast iron and fixed to the wheels and rotate with the wheels. The cylinder (brake chamber) is fixed on the brake body and fixed. The two linings on the caliper are mounted on both sides of the brake disc. The piston (push rod) of the oil cylinder (brake chamber) is subjected to the liquid (gas) pressure from the oil (gas) tube and pushes the friction plate against the brake disc to frictionally brake, just as if the pliers are used to clamp the rotation. The plate in the middle forces the moving body to stop moving.
The main technical parameters are: rated braking torque, braking radius, brake disc diameter, brake disc thickness, inner brake lining radius, brake clearance, working stroke of air chamber top rod, axial displacement of piston rod , Air chamber top rod stroke, friction plate opening force, brake lining thickness, the total area of ​​two brake linings, brake efficiency factor and braking efficiency.
â— Structural features of WABCO's air disc brakes WABCO disc brakes use a single-piston mechanism. Compared to similar products in the market today, they achieve better braking performance with the smallest parts and lightest weight. .
1. Single-piston mechanism, simpler structure, lighter weight In the past, due to the large friction plates of the vehicle, two push rods must be used to avoid wedge wear. When adjusting the gap, you need to use a very complex adjustment mechanism to synchronize the two push rods. This increases the quality of the system and also increases the probability of part damage due to the large number of parts. WABCO has made improvements to this, and has launched the PAN series of single-actuator actuators.
The single push rod actuation adjustment mechanism is simpler in structure than the double push rod actuation adjustment mechanism, the number of components is smaller, the performance is more reliable, the structure is more compact, and the assembly weight and failure rate are effectively reduced.
2. Pushing disc patented technology, can effectively prevent partial wear, and can play a role in thermal insulation 3, strong guide pin structure, work more stable WABCO single push rod disc brake guide pin in the same product in the industry diameter The largest, more stable work when guiding. One end of the guide pin is sealed with a metal end cap, and the other end is sealed with a double dust-proof sheath, making the guide pin system safer and more durable.
4. Optimized Friction Plate Size and Longer Life WABCO's research on friction plates found that reducing the surface area of ​​the friction plate within a certain range has little effect on the life of the friction plate. Based on the above results, the surface area of ​​the friction plate is reduced, the material saved is used to increase the thickness of the friction plate, the design is more compact, the service time of the friction plate is longer, and the maintenance cost is greatly reduced.
5. The wear sensor monitors the wear of the friction plate When the friction plate has been excessively worn, if it cannot be replaced in time, the brake disk may be damaged during braking. What's more serious is that the vehicle will lose braking and it is very likely to cause an accident. In order to better improve the safety of the vehicle, WABCO PAN series disc brakes can be equipped with an optional wear indicator that can warn the driver when the friction plates are 3 mm and 2 mm respectively.
The wear indicator is mounted on the friction plate and the sensor head is a coil. The coil is fixed in place. Pre-alarm can be achieved by providing two signals:
• When the coil contacts the brake disc • When the coil wears ◠WABCO disc brake specifications and main parameters WABCO disc brakes of the new generation, ie NG disc brakes, are based on PAN disc brakes Based on WABCO latest generation disc brakes.
The main features of the NG disc brakes are simple structure, light weight, large braking torque, and improved pressure distribution on the outer friction plates. NG has inherited the patented single-push technology of the PAN series. This design is compact, reliable, and lightweight. These improvements make the NG22MAX the lightest disc brake on the market today, including friction discs that weigh only 39KG. In addition, the connection between NG and the bridge is simple. The reduction in the weight of the NG series products has greatly reduced the unsprung mass, thereby reducing the impact on the chassis. At the same time, the improvement of the pressure distribution enhances the crack resistance of the brake disc and minimizes radial and tangential taper wear.
◠Application of domestic automotive disc brakes Disc brake applications in automobiles, due to the constraints of the wheel hub's external dimensions, a large number of hydraulic disc brakes are used in small cars, while heavy disc brakes use pneumatic disc brakes. . With the development of China's automobile industry technology, especially the development of the car industry, the use of disk brake configuration will gradually become a scale. In particular, it plays a major role in improving vehicle performance, ensuring safety, improving comfort, meeting people’s ever-increasing living material needs, and improving the living environment.
1. In the braking process of small cars, cars, light trucks and other small cars, due to the inertia, the load of the front wheels usually accounts for 70%-80% of the total car load, so the front wheel braking force is greater than that of the rear wheels. . From the perspective of economy and practicality, manufacturers have adopted a front-wheel disc brake and a rear-wheel drum brake hybrid matching method in order to save costs. The use of the front disc rear drum hybrid brake is also due to the fact that when the car is in emergency braking, the axle load is moved forward, and the front wheel braking performance requirements are relatively high. Such front brakes mainly use hydraulic disc brakes as the mainstream, and hydraulic oil is used as the front brake. The transmission medium uses the main hydraulic pump as the power source, and the rear brake is matched with the hydraulic cylinder's double-acting cylinder brake shoes.
At present, most of the cars, mini-cars, light trucks, SUVs, and pickups use front-rear-drum hybrid brakes. However, with the increase in the level of highways and the rise in the number of riders, especially the enforcement of national security regulations, the use of disc brakes in front and rear wheels will be an inevitable trend.
2. The technical advancement of disc brakes for large passenger vehicles is obvious, the reliability is generally good, and the innovation and technical standards are integrated. European and American countries have started to use disc brakes for large buses since the early 1990s. By the year 2000, disc brakes (disc brakes both front and rear) had become the standard for urban buses in Europe and the United States. China began to promote disc brakes and ABS anti-lock braking systems on buses and trucks in 1997. However, due to the high price of imported products, it is mainly used for high-end products.
After the Ministry of Transport forced the “must†equipment on the 9m or higher type II buses in 2004, the disc brakes became popular. Bus companies such as Beijing, Shanghai, Guangzhou, Shenzhen, and Wuhan are all using air disc brakes that are compatible with buses. At present, large domestic well-known manufacturers have mass-produced high-end passenger cars with disc brakes.
3. Heavy-duty vehicles As a new application technology in the heavy-duty automotive industry, disc brakes are mature products. Domestic large-scale automobile plants have completed preliminary tests and technical stocking of disc brakes in heavy-duty vehicles. Disc brakes can be said to be the new trend in the future development of heavy-duty truck brake systems.
â— Development Trend of Domestic Automotive Disc Brakes Europe, the United States, Japan, and other developed countries have equipped disc brakes as standard components on multi-level cars, passenger cars, medium-sized and heavy-duty vehicles. With the promotion of national laws and regulations, such as GB 7258-2004 "Motor Vehicle Operation Safety Technical Conditions" (upcoming revision based on the 2004 version) and GB 24407-2012 "Specialized School Bus Safety Technical Conditions", it is expected that in the next few years, disc type Brakes will be rapidly promoted and applied in China.
The new edition of GB 7258 stipulates that the front axle of a dangerous goods transport vehicle and the front axle of a bus with a vehicle length of more than 9m should be equipped with disc brakes; the new version of GB 24407 requires that disc brakes be installed on the front wheels of special school buses. The problems that should be paid attention to in the research and development of modern automobile disc brakes are mainly to improve the braking efficiency of brakes, prevent dust and corrosion, reduce weight, simplify structure and reduce costs, and develop electronic warning and intelligent systems, which are more practical. Longer life.