ee types: polyurethane tape, polyurethane core tape and rubber canvas core tape. In the rubber micro-belt, in addition to chemical fiber canvas, there are special products using nylon diaphragm, aramid cord, glass fiber cord as core and surface rubber coated with chrome. They are essentially different from traditional canvas slabs. The specifications are very precise and the added value is very high. The world's major tape manufacturers are racing to develop and become high-tech products in the rubber industry. At present, Germany's Jin Yulin, Switzerland's Habaki, Radar, and Japan's Xintian are well-known large companies in this field, and the high-end and special micro-belts based on polyurethane are the leading products of their full development. .
The V-belt, also known as the V-belt, is the most productive, wide-ranging and most versatile product in the transmission belt. Since the first automobile roll belt made in the United States in 1917, it has been popularized for industrial and agricultural machinery since the early 1920s. It has been growing for more than half a century and has developed rapidly. It has become the mainstream of the transmission belt. In the world's transmission belts, from the point of view of rubber consumption, the V-belt now accounts for 65%, the toothed belt is 25%, and the flat belt has been reduced to less than 10%. At present, the V-belt has become the main equipment for power transmission and shifting of various mechanical devices in the world. It plays an increasingly important role in many fields such as agricultural machinery, machine tools, automobiles, ships and office equipment.
According to the section size, the V-belt can be divided into seven industrial models of industrial machinery for Y, O, A, B, C, D, and E, and various types of fan belts for automobiles and tractors. Y and O are the smallest V-belts, mainly used in office equipment such as typewriters and book cutting machines, and home appliances (washing machines, juicers, vacuum cleaners). General industrial machinery, with the increase of horsepower, sequentially use V-belts such as A, B, C, D, E, etc., D and E are heavy-duty belts, used for 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 pumps and air conditioners. In developed countries, the production ratio of the V-belt to the fan belt has reached 2:1-3:2, and the fan belt has shown a significant upward trend.
The V-belts generally refer to the V-belts. Since the 1960s, in order to improve the durability of the belt, a V-belt has been introduced. This trimmed V-belt has been rapidly developed due to the fact that the side of the tape structure is not covered, the belt body is very soft, and the flexural fatigue resistance is very good. In the 1980s, in order to solve the problems of transmission efficiency and service life caused by the generation of different lengths of the V-belt in the group drive, a plurality of V-belts with the V-belts fixed together were brought up. The V-shaped flat belt, which is accustomed to be called a combined set of V-belts, has great advantages, and thus the phenomenon that the V-shaped flat belt replaces the wrapped and trimmed triangular belts has begun to appear. The tape combined with the flat belt has special requirements for the groove of the pulley. However, since the belt is thin, the contact area with the pulley is large, the bending property is good, and the pulley is reduced, so that the transmission device can further Miniaturization and energy saving have led to a sharp increase in production in developed countries around the world.
In recent years, in order to meet the special needs of various transmission devices, in addition to the ordinary standard type of V-belts, there are also a large number of special triangular belts of various shapes, which mainly include:
(1) Narrow and wide V-belts
The ordinary V-belt has an aspect ratio of 1:1.5 to 1.6, while the narrow and wide V-belts are 1:1.2 and 1:2, respectively. The structure size of the narrow V-belt can be reduced by about 50% compared with the conventional V-belt, which can save a large amount of raw materials, at the same time, the strength is uniform, the effective contact area is large, the bending stress is small, and the service life can be greatly extended. The narrow v belt has a transmission efficiency of 90% to 97%, a limit speed of 40-50m/s, and a transmission capacity of 0.5 to 1.5 times. It is most suitable for short-distance and small pulleys in variable speed transmission. Also known as the shift belt. It is characterized in that the upper and lower surfaces of the belt are mostly made into a single-sided or double-sided curved or toothed state, which makes it easy to adjust speed, and is mainly used in low-speed cone and disc type continuously variable transmissions.
(2) Small and large angle triangles
The main difference between it and the ordinary V-belt is that the angle 40' is changed to 30' and 60'. The small-angle V-belt can reduce the contact surface, reduce the required tension, extend the service life, and is suitable for small tension transmission of equipment. The large-angle V-belt has a rectangular shape in the upper half and an inverted trapezoidal hexagonal belt in the lower half, which can reduce the friction loss, increase the bearing capacity, and the belt body is soft, and is suitable for high-speed transmission of light and small equipment.
(3) Active and rushing L-belt
The active tape is made up of a plurality of small segments joined by metal screws. The punching belt has a plurality of equidistant through holes in the longitudinal direction of the belt for connecting the joints. These V-belts are all V-belts that can be joined, and can be freely fixed according to the length of the joint. It makes up for the limitation that the ordinary V-belt has no joints 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 replaceable damaged part can be used continuously, and at the same time, it has the advantage of being able to easily adjust the length. However, due to the low strength, it can only be used for low-speed transmission, and due to problems such as low precision and poor transmission efficiency, the use has been decreasing in recent years.
In addition, a V-belt designated for driving a fan of various internal combustion engines such as automobiles and tractors is specifically called a fan belt. It is characterized by a single use, a small pulley, a short distance, a constant speed and power, and is a V-belt that is used at high contact temperatures and in harsh environmental conditions. Fan belts are also commonly used in generators, compressors, and power. Fan strips are classified separately in the industry due to their performance requirements being completely different from ordinary V-belts. In recent years, the development of the world fan belt has been very rapid, and the number has accounted for one-third of the total amount of the V-belt.
The fan belt is divided into two types: ordinary and narrow, and is subdivided into various types such as a covered flat V-belt, a scalloped V-belt, a trimmed flat-bottom V-belt, and a wave V-belt. The structure of the fan belt is generally more complicated than that of a conventional V-belt. Referring to the drawings, in addition to the strength layer, the stretch layer, the compression layer and the wrap layer, a buffer layer and a support layer are added.
Nowadays, the most used is the trimming wave V-belt, which has low heat generation, fast heat dissipation, large friction, low noise, good strength and high efficiency. The mileage can reach 180,000 to 200,000 kilometers, which is about twice as high as the average fan belt. . In recent years, with the improvement of the efficiency of automobile engines and the emergence of rotary engines, as well as the increase of hydraulic steering devices and cold air devices, the requirements for fan belts have become increasingly severe, not only the miniaturization of pulleys, but also the use of two-way two-sided driving. The more, therefore, the rubber and core material also produced a major 舀I~, `IIit ordinary V-belt, V-shaped flat belt and fan belt comparison 1-upper tape layer: 2-low tape layer; 3-rubber stretch Layer: 4-rubber compression layer: 5-wire strength layer; 6-rubber buffer layer: 7-~tgrg
1.3 round belt
The circular belt is a circular belt with a circular cross section that can be flexibly driven. This kind of belt is mostly made of polyurethane, usually has no core, the structure is the simplest and easy to use. The circular belt opens up a new way for the belt transmission. The demand for small machine tools, sewing machines and precision machinery in the world is increasing rapidly, and the potential is great in the future.
1.4 toothed belt
The toothed belt is also called a timing belt, and is divided into a single-sided tooth belt and a double-sided tooth belt. The former is mainly used for single-axis transmission, and the latter is multi-axis or reverse transmission. It is another high-efficiency transmission belt that has emerged in the world since 1980. The toothed belt is further divided into a trapezoidal shape and a circular arc shape according to the shape of the tooth, and the torque of the synchronous belt of the circular arc-shaped tooth is maximized. From the materials used, the toothed belt can be divided into rubber type and polyurethane type, and the former has ordinary rubber (usually neoprene) and special rubber (mostly saturated nitrile rubber). Their structure is composed of a strong layer composed of steel cord or glass fiber and an outer rubber layer or polyurethane rubber layer formed of rubber and nylon cloth.
The toothed belt, including the V-ribbed belt, has developed extremely rapidly in industrialized countries in the past 20 years and is continually eroding the traditional metal gears, chains and rubber belts and V-belts. At present, in addition to a large number of used in the automotive and traditional industries, and further expanded to the transmission of various precision machinery such as OA machines (office equipment) and robots. Thanks to the elastic teeth on the inside of the tape, it can realize the synchronous transmission without sliding, and it has the characteristics of lighter than the chain and low noise. Today, more than 80% of the cars in Europe and 40% of the cars in the United States have already equipped the teeth. Type belt. In 2000, China produced 2 million vehicles and more than 7 million toothed belts. Recently, the scalloped belt has increased the transmission force and quietness compared with the square tooth belt. As a new generation of environmental protection belt, its use range is more extensive. Nowadays, it has become the object of use for household and industrial sewing machines, typewriters and copying machines that are extremely strict with synchronous transmission and noise.
2. Technology outlook
For more than half a century, the technological development of the world's transmission belts has gone through the following stages:
First, from the material used in the transmission belt, the rubber has been developed from natural rubber to synthetic rubber, and further expanded to special
Synthetic rubber CSM, HNBR: The skeleton material is expanded from cotton fiber to rayon, polyester, nylon, glass fiber, steel wire and aramid, as shown in Table 2. Product. In order to improve the durability of the V-belt, since the 1960s, a cut-type V-belt has appeared, and its side has no wrap, and the bending fatigue resistance is very good, and has replaced most of the wrap-around V-belts.
On the other hand, after entering the 1980s, the V-belt tape with the flat belt and the V-belt was rapidly developed. Due to its excellent performance and sharp increase in output, the cutting V-belt has been partially replaced. Then, in the United States and Japan and other countries, a wedge-shaped V-belt appeared. Since the belt has a small thickness, a large contact area with the pulley, and good bending performance, it can be used on a small pulley, and thus contributes greatly to miniaturization and energy saving of the transmission.
Furthermore, the principle of driving on the back of the belt can be used. For example, in the automobile fan, AC motor, power control system, air conditioner, etc., the so-called "snake drive" method that uses one drive belt for one drive has attracted attention from all walks of life. Increasingly. Representative products for such multi-faceted, multi-directional, multi-machine transmissions are hex belts and round belts.
The latest category of products in the drive belt is the toothed belt, also known as the timing belt. It combines the advantages of gears, chains and belt transmissions, and has the characteristics of high transmission efficiency, accurate transmission ratio, low noise, energy saving and convenient maintenance. Although its transmission principle appeared in 1900, several patents appeared. However, it was not until half a century later that industrialization began. In the 1980s, it finally became the leading transmission product of precision machinery. In particular, high-precision micro-belts made of saturated nitrile rubber and polyurethane elastomers have entered the high-tech field. The biggest difference between the toothed belt and the traditional transmission belt is: synchronization and mute. Therefore, it is the most respected environmentally friendly product today. In recent years, after the tooth of the toothed belt is changed from a square tooth to a scalloped tooth, the transmission force is further increased, and the development prospect is extremely broad.
Due to the different characteristics of various mechanical requirements and the wide difference in price between various transmission belts, the transmission belt will be developed in the direction of diversification of structure and materials, and its use and variety specifications will become increasingly diversified. Drive belt V。