2006 is the first year of the Eleventh Five-Year Plan. The national economy continues to maintain a good momentum of steady and rapid development, and the coal industry also maintains a good momentum of development with faster speed, better benefits, higher prices and stable operation. Production and sales continue to grow synchronously, supply and demand are basically balanced, corporate profits continue to increase, and the growth rate of coal fixed assets investment declines, which is conducive to the development of the coal industry. According to the statistics express, on the whole, the operation quality of the industry continues to improve, laying a good foundation for the development in 2007.
The ancients said, "Be prepared for danger in times of peace, be prepared for danger in times of peace." . Since 2002, although the coal industry is in a good situation, conveyor belt factories all over the country have blossomed everywhere and achieved fruitful results. However, the road ahead of us is uneven, so we need to be careful to keep a cool head and the situation will be better. From June 5438+0 to February 65438+2, 2006, the death toll of coal mine production in China was still as high as 4746. Therefore, it is still very important to improve the quality and detection level of coal mine products, especially conveyor belts.
First, the development of conveyor belts in China
At present, there are more than 90 conveyor belt manufacturers in production, and several others are applying. Among them, there are 2 1 home manufacturers who produce rubber-covered full-core flame-retardant conveyor belts and plastic-covered full-core flame-retardant conveyor belts 1600s or more, the highest grade of rubber-covered full-core flame-retardant conveyor belts is 2800s, two are in production, and the highest grade of plastic-covered full-core flame-retardant conveyor belts is 2240s, and only one is in production. There are 42 enterprises that can produce integral belt cores and flame-retardant conveyor belts. There are 23 manufacturers and 54 production lines that produce mine steel wire rope core conveyor belts. The highest grade of mine steel wire rope core conveyor belt that can be produced is ST/S5400.
The average annual output of coal in China is more than 2 billion tons, and the consumption of mine conveyor belt is more than 65.438+0.4 million meters, of which the consumption of steel wire rope conveyor belt is about 2.5 million meters. Before 2000, the coal-consuming conveyor belt was 1.8 yuan, and now it is probably 1.2 yuan.
However, because there are many domestic manufacturers of conveyor belts, few enterprises have really formed a certain scale and brand, and many enterprises do not attach importance to technological innovation and the improvement of their own testing ability, and constantly repeat backward processes and formulas. Therefore, while the entire tape industry is developing rapidly, there are also many unfavorable factors that lead to disorderly competition due to the nonstandard domestic market. First, blind development, enterprises are small and scattered; Second, many small factories have no standard production, and the price is actually for sale; Third, the brand awareness is poor, only seeking low prices, regardless of quality; Fourth, the market lacks necessary rectification and guidance. Therefore, the production quality of domestic conveyor belts needs to be further improved.
2. The gap at home and abroad
The number of conveyor belt manufacturers in China is the sum of other countries in the world. However, in the aspects of raw material quality control, technical document control (especially process) and operating procedures, it lags far behind some advanced conveyor belt manufacturers abroad, especially in automatic production and control. At the same time, in the training of conveyor belt professionals, as well as manufacturers' awareness of pre-sales and after-sales service is not strong enough.
Three. Actions and measures to be taken
1) We should accurately grasp and understand the relevant policies and information of the country, and at the same time grasp the spirit of the policy, which also provides us with an opportunity to re-understand and analyze the market. At the same time, we should be sensitive to market changes.
To cultivate and attach importance to talents, we must constantly improve the quality of employees in enterprises. If the enterprise is compared to the mouth, our goal is "no tooth decay". At the same time, we should constantly improve the internal culture and positive values of the enterprise.
3) Be brave in innovation and attach importance to research and development. According to the different working environment of conveyor belt, products with different performances are developed and designed.
4) Do a good job in pre-sales and after-sales service. Pre-sale service: actively communicate with potential customers and fully understand their industrial and mining conditions (such as the number and model of conveyor belts, coal consumption per ton, the length and life of a single conveyor belt, coal conveying capacity and speed, etc.). ) and supporting equipment. After-sales service: communicate with customers regularly, follow up the service and solve customers' problems in time.
5) Establish a conveyor belt standard for coal mines with reasonable structure, strong practicability and international standards, and carry out production and quality control in strict accordance with the requirements of the standard.
6) Management agencies should also strengthen the supervision and management of conveyor belt production enterprises and coal mine users.
In a word, in order to make our domestic conveyor belt manufacturers survive in the increasingly fierce international competition, we need to strictly control the development trend, product structure, required functions, materials used, process equipment, market forecast and so on.
Second, the conveyor belt industry basic knowledge
Conveyor belt, also called conveyor belt, is a composite product of rubber, fiber and metal, or a composite product of plastic and fabric, which is used for carrying and conveying materials in belt conveyor. Belt conveyor is widely used in agriculture, industrial and mining enterprises and transportation industry to transport all kinds of solid and powdery materials or finished products. It can be transported continuously, with high efficiency, large inclination, safe operation, simple use, convenient maintenance and low freight, which can shorten the transportation distance, reduce the engineering cost and save manpower and material resources.
There are many kinds of conveyor belts, which are classified according to their uses: general conveyor belts, flame-retardant antistatic conveyor belts, general flame-retardant conveyor belts, heat-resistant conveyor belts, high-temperature conveyor belts, acid and alkali-resistant conveyor belts, oil-resistant conveyor belts and cold-resistant conveyor belts.
According to the structural materials, there are: ordinary cotton canvas conveyor belt, nylon conveyor belt, polyester conveyor belt, steel wire rope core conveyor belt, PVC integral conveyor belt, PVG integral conveyor belt, steel wire rope conveyor belt, etc.
According to the product structure, there are layered conveyor belt, integral conveyor belt, steel wire rope core conveyor belt, steel wire rope conveyor belt, tubular conveyor belt, patterned conveyor belt, edge-blocking conveyor belt and laminated conveyor belt.
For convenience, we generally use a unified representation to represent all kinds of conveyor belts and conveyor belts.
1, the common representation of layered conveyor belt (the standard representation is different from this, please refer to GB7984 for details):
Take NN200 1000×6(6+3) as an example, NN200 represents nylon 200, 1000- represents belt width, 6- represents the number of nylon cloth layers, and (6+3)- represents the thickness of the upper and lower covering glue of the conveyor belt is 6 mm and 3 mm respectively.
2, wire rope conveyor belt commonly used expressions:
With ST 1000 H 1000? Take 4.0-6.0-6.0 as an example:
ST 1000- indicates the strength specification, that is,1000 n/mm.
H- indicates the performance level of the covering adhesive.
1000- indicates the width of the product in millimeters.
? 4.0- indicates the diameter of the wire rope, in millimeters.
6.0-6.0- indicates the thickness of the upper and lower covering glue in millimeters.
3, the whole core conveyor belt representation method
PVC and PVG integral flame-retardant conveyor belts for coal mines are generally expressed by strength grade and bandwidth. General strength grades are divided into: Grade 4, Grade 5, Grade 6, Grade 7, Grade 8, Grade 9, 10,1and the highest 16. The corresponding strength is 680S, 800S, 1000S respectively. The width of the conveyor belt is generally 500mm, 650mm, 800mm, 1000mm, 1200mm, 1400mm, 1600mm, 1800mm, etc.
According to China's regulations, all conveyor belt products used in coal mines must be flame retardant and antistatic conveyor belts that meet China's relevant standards. At present, the commonly used conveyor belts in coal mining enterprises are: PVC integral flame-retardant antistatic conveyor belt, PVG integral flame-retardant antistatic conveyor belt and steel wire rope core flame-retardant antistatic conveyor belt.
Flame-retardant antistatic conveyor belt mainly stipulates the safety performance of products: 1, alcohol burner burning; 2. Surface resistance; 3. Roller friction; 4. Simulate the combustion of propane in the road. These inspection items characterize the safety performance of products.
Development Status and Prospect of Transmission Belt in the World
Transmission belt is the power generated by the rotation of the motor or engine of the prime Mover, which is transmitted to the mechanical equipment through the pulley, so it is also called power belt. It is the core connecting component of mechanical and electrical equipment, with a wide variety and extremely wide application. From giant motors as large as several thousand kilowatts to micro motors as small as less than one kilowatt, even precision machinery such as home appliances, computers and robots cannot do without transmission belts. Its biggest feature is free speed change, far-near transmission, simple structure and convenient replacement. Therefore, from primitive machinery to modern automation equipment, there are transmission belts, and the products have evolved many times, and the technology is becoming more and more mature.
Power transmission has many forms, such as chain, gear and coupling. But from the perspective of economy and cost, so far, it is nothing more than elastic tape. Therefore, many transmission modes in the world are still dominated by belt transmission, and its development is still expanding.
The transmission belt was originally made of leather and was replaced by rubber in the middle of19th century. Since 1960s, NR and SBR have turned to CR and PUR. In the1980s, it was further expanded to adopt CSM and HNBR. The shape of the belt has also expanded from plate to angle, circle and tooth, and its use has developed from single drive to group parallel connection, forming today's transmission belt series.
1, development status
Transmission has two functions: transmission and speed change, which are divided into friction transmission and meshing transmission. Up to now, four systems of V-belt, flat belt, toothed belt and round belt have been formed in the structure and shape of transmission belt manufacturers all over the world, including 1000. Especially, as a high-tech product in rubber industry, toothed belt has developed very rapidly in the world with the progress of precision machinery and electronic information technology in recent ten years, and its output has expanded sharply. Classification of transmission belts.
1. 1 flat strip
Flat belt is the oldest variety of transmission belt, with a history of about 100 years, but it still occupied about half of the market share of transmission belt until the middle of the 20th century. Because of its simple structure, convenient transmission, unlimited distance and easy adjustment and replacement, it is widely used in various industrial and agricultural machinery. Generally, the width of flat belt is 16-600mm, the length can reach 100-200 m, and the maximum number of layers can reach 6. Canvas belt is the most common kind of belt, which can be divided into three types: cladding, laminating and overlapping. Laminated belt is an improved product of composite belt (also known as round edge belt), which has the advantages of soft belt body, elasticity and good bending resistance. It is suitable for small pulleys and fast transmission devices with speed greater than 20 m/s, and the overlapping belt is between them, which is used for transmission with easily worn edges. Due to the low efficiency of flat belt drive (generally about 85%) and the large occupied area, the output of all countries in the world has been declining year by year since the 1960s. At present, in developed countries, except some agricultural machinery and textile machinery are still used in small quantities, they have been eliminated. On the other hand, during this period, great progress has been made in the world in joint-free endless belts and hot joints made of chemical fiber canvas and curtain cloth. It has the characteristics of high strength, low noise, smooth transmission, smooth transportation, flexible resistance, long service life and no need for joints, and its application field has been expanding, which has become the mainstream of miniature transmission belts.
In recent years, with the rise of high-tech industry, this kind of microstrip has been widely used in computer peripherals, office automation equipment and labor-saving equipment. Such as automatic ticket vending machines, ticket vending machines, money changers, ticket vending machines, cash machines, bank settlement machines, automatic inspection machines, photocopiers, medical devices, automatic packaging machines, fish detectors, etc. The United States, Japan, Europe and other countries are growing at a double-digit rate every year.
This high-performance seamless flat belt has developed into three types: polyurethane belt, polyurethane core belt and rubber canvas core belt. In rubber microstrip, in addition to chemical fiber canvas, there are also special products with nylon diaphragm, aramid cord and glass fiber cord as the core and chrome leather coated with rubber. They are essentially different from the traditional canvas flat belt, with very accurate specifications and high added value. The world's major belt manufacturers are competing to develop and have become high-tech products in the rubber industry. At present, Germany's Kinkling, Switzerland's Habakki, Rado and Japan's Xintian are all well-known large-scale enterprises in this field, and their leading products are high-grade special microstrip based on polyurethane.
1.2 V-belt
V-belt, also known as V-belt, is the product with the largest output, the largest variety and the widest application in transmission belt. Starting from 19 17, automobile fan belts were first made in the United States, and they were widely used in industrial and agricultural machinery in the early 1920s. After more than half a century of vigorous development, it has now become the mainstream of transmission belts. As far as rubber consumption is concerned, V-belt accounts for more than 65%, toothed belt accounts for 25% and flat belt accounts for less than 65,438+00%. At present, V-belt has become the main equipment for power transmission and speed change of various mechanical devices in the world, and plays an increasingly important role in a wide range of fields such as agricultural machinery, machine tools, automobiles, ships and office equipment.
According to the cross-sectional size, V-belts can be divided into seven industrial models: Y, O, A, B, C, D and E for industrial machinery, and various fan belts for automobiles and tractors. Y-type and O-type are the smallest V-type belts, which are mainly used in office equipment such as typewriters and book cutters and household appliances (washing machines, juicers and vacuum cleaners). With the increase of horsepower, V belts such as A, B, C, D and E are used in general industrial machinery, among which D and E are heavy belts, which are used in large machinery such as ships and electric power. As for the fan belt, in addition to cars and tractors, it is also widely used in water pumps and air conditioners. In developed countries, the output ratio of V-belt to fan belt has reached the level of 2: 1-3: 2, and fan belt shows an obvious upward trend.
V-belts generally refer to winding V-belts. Since 1960s, it seems that dressing V-belt can improve the durability of transmission belt. This trimming V-belt has developed rapidly because there is no cloth on the side of the belt structure, the belt body is very soft and the bending fatigue resistance is very good. In 1980s, in order to solve the problem of transmission efficiency and service life reduction caused by different lengths of multiple V-belts in group transmission, a number of V-belts fixed together by flat belts appeared. V-shaped flat belt, which used to be called combined V-belt, has great advantages, so the phenomenon that V-shaped flat belt replaces wrapped V-belt and trimmed V-belt begins to appear again. Although there are special requirements for pulley grooves, this kind of adhesive tape combined with V-belt and flat belt has the advantages of thin belt body, large contact area with pulley, good flexibility and reduction of pulley, which can further miniaturize the transmission device, save energy and increase the output of developed countries in the world.
Four. Development Status and Prospect of Transmission Belt in the World (Ⅱ)
In recent years, in order to meet the special needs of various transmission devices, in addition to ordinary standard V-belts, a large number of special V-belts with different shapes have appeared, mainly including:
(1) narrow v-band and wide v-band
The width-height ratio of the common triangle is 1: 1.5 ~ 1.6, and the narrow and wide triangles are 1: 1.2 and 1: 2 respectively. Compared with the common V-belt, the structural size of narrow V-belt can be reduced by about 50%, which can save a lot of raw materials, and at the same time, it has uniform strength, large effective contact area and small bending stress, which can greatly prolong the service life. The transmission efficiency of narrow V-belt can reach 90%-97%, the limit speed can reach 40-50m/s, and the transmission capacity is increased by 0.5- 1.5 times. It is most suitable for short-distance and small pulley stepless transmission, so it is also called stepless speed change belt. It is characterized in that the upper and lower surfaces of the belt are mostly made into single-sided or double-sided arc or tooth-shaped state, which is convenient for speed regulation. Mainly used for low-speed conical and disc CVT.
(2) Triangle belt with small angle and large angle
The main difference between it and ordinary triangle belt is that the included angle of 40'' is changed to about 30'' and 60''. Small angle V-belt can reduce the contact surface, reduce the required tension and prolong the service life, which is suitable for small tension transmission of equipment. Large-angle V-belt is a hexagonal belt with rectangular upper part and inverted trapezoid lower part, which can reduce friction loss, increase bearing capacity and make the belt soft, and is suitable for high-speed transmission of light and small equipment.
(3) activating and punching the L-shaped V-belt
The movable belt is formed by connecting a plurality of small sections with metal screws. The punching belt is punched with many equidistant through holes in the longitudinal direction of the belt body to connect the joints. These V-belts are all spliced V-belts, which can be freely spliced and fixed according to the required length. It makes up for the limitation that the common V-belt has no joint and can only be used according to the specified length. Another advantage is that in use, when the V-belt body is partially damaged, the damaged part can be replaced for continuous use, and at the same time, the length adjustment is simple and free. However, due to its low strength, it can only be used for low-speed transmission, and it is less and less used in recent years due to problems such as low precision and poor transmission efficiency.
In addition, the V-belt, which is specially used to drive the fans of various internal combustion engines such as automobiles and tractors, is called the fan belt. It is characterized by one-time use, small pulley, short transmission distance and constant speed and power. It is a V-belt with high contact temperature and harsh environmental conditions. Fan belts are also commonly used in generators, compressors, power pumps, etc. Because the performance requirements of fan belts are completely different from those of ordinary V-belts, they are classified and counted separately in industry. In recent years, the development of fan belts in the world is very rapid, and the number has accounted for one-third of the total number of V belts.
Fan belts are divided into ordinary and narrow types, and subdivided into winding flat-bottomed V-belts, fan-shaped V-belts, trimming flat-bottomed V-belts and corrugated V-belts. The structure of fan belt is generally more complicated than that of common V belt. As shown in the attached figure, in addition to the strength layer, tensile layer, compression layer and cloth layer, a buffer layer and a support layer are added.
At present, the trimmed V-belt is widely used, which has the advantages of low heating, fast heat dissipation, large friction, low noise, good strength and high efficiency, and the driving mileage can reach18 ~ 200,000 kilometers, which is about twice as high as that of ordinary fan belts. In recent years, with the improvement of automobile engine efficiency and the emergence of rotary engines, as well as the increase of hydraulic steering devices and air-conditioning devices, the requirements for fan belts have become more and more demanding. Not only the pulley is miniaturized, but also more and more bidirectional and bilateral driving modes are adopted. Therefore, rubber and core materials also produced a large spoon. V-shaped flat belt is 1- upper belt layer: 2- lower belt layer compared with fan belt. 3- rubber tension layer: 4- rubber compression layer: 5- rope strength layer; 6- rubber buffer layer: 7-~tgrg
1.3 round belt
The endless belt is a transmission belt with a circular cross section, which can be bent and driven freely. This kind of belt is mostly made of polyurethane, usually without core, with the simplest structure and convenient use. The endless belt has opened up a new way of belt transmission, and the demand for small machine tools, sewing machines and precision machinery in the world has increased sharply, which has great potential in the future.
1.4 toothed belt
Toothed belts, also known as synchronous belts, are divided into single-sided toothed belts and double-sided toothed belts. The former is mainly used for single-shaft transmission, and the latter is multi-shaft or reverse transmission, which is another new type of high-efficiency transmission belt in the world after 1980. According to the shape of the teeth, the toothed belt can be divided into two types: trapezoid and arc, and the arc-toothed synchronous belt bears the largest torque. According to the materials used, toothed belt can be divided into rubber type and polyurethane type, while the former can be divided into ordinary rubber (usually chloroprene rubber) and special rubber (mostly saturated nitrile rubber). Their structure consists of a strong layer made of steel cord or glass fiber and an outer rubber layer or polyurethane rubber layer made of rubber and nylon cloth.
Toothed belts, including V-ribbed belts, have developed rapidly in industrialized countries in recent 20 years, eroding the traditional markets of flat belts and V-belts in metal gears, chains and rubber. At present, it has been widely used in automobiles and traditional industries, and further extended to the transmission of precision machinery such as OA machines (office equipment) and robots. Because of the elastic teeth on the inner side of the belt, synchronous transmission can be realized without slipping, and it is lighter than the chain and less noisy. At present, more than 80% cars in Europe and 40% cars in the United States have installed this toothed belt. In 2000, China produced 2 million cars and needed more than 7 million toothed belts. Compared with the square toothed belt, the nearest circular toothed belt further increases the transmission force and quietness. As a new generation of environmental protection belt, its application scope has become more extensive. Now it has been used by sewing machines, typewriters and photocopiers for home and industry. These devices have extremely strict requirements for synchronous transmission and noise.
2. Technology prospect
For more than half a century, the technical development of transmission belts in the world has gone through the following stages:
1. From the materials used in the transmission belt, rubber has developed from natural rubber to synthetic rubber, and further extended to special synthetic rubber CSM and HNBR: the skeleton materials have expanded from cotton fiber to rayon, polyester, nylon, glass fiber, steel wire and aramid fiber, as shown in Table 2. Products. In order to improve the durability of V-belts, cut V-belts have appeared since the 1960s, and their sides are not covered with cloth, so they have excellent bending fatigue resistance and have replaced most of the subcontracted V-belts.
On the other hand, after 1980s, V-shaped flat belts with flat belts and V-shaped belts developed rapidly. Because of its excellent performance and large increase in output, it has partially replaced cutting V-belt. Then in the United States, Japan and other countries, a wedge-shaped V-belt appeared. Because of its thin thickness, large contact area with pulleys and good bending performance, this belt can be used on small pulleys, thus making great contributions to miniaturization and energy saving of transmission devices.
In addition, the principle that the back of the transmission belt can also be driven is used, for example, in automobile fans, AC motors, power control systems, air conditioners and the like. The so-called "snake drive" mode of a driving belt has attracted attention from all walks of life, and its application scope is expanding day by day. The representative products of this multi-faceted, multi-directional and multi-machine transmission are hexagonal belt and round belt.
The latest product of transmission belt is toothed belt, also known as synchronous belt. It combines the advantages of gear, chain and belt transmission device, and has the characteristics of high transmission efficiency, accurate transmission ratio, low noise, energy saving and convenient maintenance. Although many patents appeared on its transmission principle as early as 1900, it didn't start industrialization until half a century later, and finally became the leading transmission product of precision machinery since the 1980s. In particular, high-precision microstrip made of saturated nitrile rubber and polyurethane elastomer has entered the high-tech field. The biggest difference between toothed belt and traditional transmission belt is synchronization and silence. Therefore, it is the most respected environmental protection product today. In recent years, after the teeth of toothed belt are changed from square teeth to round teeth, the transmission force is further increased and the development prospect is extremely broad.