A spring is a mechanical part that uses elasticity to work. Parts made of elastic materials will deform under the action of external force, and then return to the original state after removing the external force. Also called “spring”. It is generally made of spring steel. The types of springs are complex and diverse. According to their shapes, they mainly include coil springs, scroll springs, plate springs, special-shaped springs, etc.
Origin of development
Like most other basic mechanisms, metal springs have been around since the Bronze Age. Even metal, wood is used as a flexible bow and structural member for military catapults. In the Renaissance , precise clocks made precision springs a necessity for the first time. The fourteenth century saw the development of precise clocks that revolutionized celestial navigation. The exploration of the world and the conquest of the European colonial powers continued to power the watchmakers’ science and art. Another field of firearms, propelled the development of springs. The Industrial Revolution of the eighteenth century brought forth springs that were large, accurate and cheap. Whereas watchmakers’ springs tend to be handmade, springs are mass produced in piano wire or similar materials. Advanced manufacturing methods make springs ubiquitous. Computer controlled wire and sheet metal bending machines allow for custom springs Obviously, this is a special machine. The spring is just an accumulator , it has the function of storing energy, but it cannot release the energy slowly. The realization of “than mechanism” is common in mechanical watches. Springs have been used a long time ago. Ancient bows and crossbows are two kinds of springs in a broad sense. The inventor of the spring should strictly be the British scientist Robert Hooke (Robert Hooke) , although helical compression springs have appeared and are widely used at that time, but Hooke proposed ” Hooke’s Law ” – the elongation of the spring is proportional to the magnitude of the force it is subjected to. It is based on this principle, in 1776, A spring balance using a helical compression spring came out. Soon, a spring made based on this principle for use in watches was also invented by Hooke himself. And a spring that conforms to “Hooke’s Law” is the real spring. Disc springs Invented by the French Belleville, it is a washer-type spring with a truncated conical section made of sheet metal or forged blanks. After the emergence of modern industry, in addition to disc springs , gas springs , rubber springs, vortex springs also appeared . coil springs, die springs,Stainless steel springs , air springs , memory alloy springs and other new springs. 
For the spring industry, for a long time, there has been a passive situation in which the supply of low-grade ordinary springs exceeds the demand, and the supply of high-end products (high-strength, high-stress, heterosexual parts, and special materials) is in short supply. The output of my country’s spring industry has become saturated. According to experts’ statistics, the annual output of springs in my country has reached 4 billion pieces. There are 21 categories and more than 1,600 varieties of various spring products, mainly including valve springs, suspension springs, and diaphragm springs. , damping springs, hydraulic springs, oil pump springs, disc springs, high temperature springs, circlips, tension springs, torsion springs, compression springs, scroll springs and heterosexual springs. The spring industry developed rapidly during the “Eighth Five-Year Plan” and “Ninth Five-Year Plan” period, especially in Shanghai, Tianjin, Guangzhou, Shandong, Changchun, Chongqing and other regions. There are also different degrees of development in other regions. better than other industries. Automobiles, motorcycles, mopeds, internal combustion engines, electrical appliances, instruments, etc. will also develop, and the development of these industries will drive the development of the spring industry. In the face of the macroeconomic situation , the contradictions of low product quality, loose organizational structure and weak development ability formed by the long-term accumulation of the industry have become more prominent. From deep-level excavation, it is mainly the problems in the market, system and mechanism. Industry insight researchers believe that with the development of national As the economy changes from a seller’s market to a buyer’s market, some deep-seated contradictions, especially the structural contradictions accumulated over the years, have become increasingly prominent. The current unreasonable industrial structure is manifested as: some industries have excess production capacity and unreasonable product structure; unreasonable technical structure, low level of equipment in major industries; small and scattered enterprise organizations, lack of competitive strength and advantages, regional structure convergence, failure to reflect Comparative advantage and collaborative benefits. 
Although the spring industry is a small industry in the entire manufacturing industry, its role cannot be underestimated. The country’s industrial manufacturing and automobile industry should speed up the development, and the spring industry, one of the basic parts and components, needs to have an early stage of development in order to adapt to the rapid development of the country’s entire industry. In addition, the expansion of the scale and variety of spring products and the improvement of the quality level are also the needs of the replacement of mechanical equipment and the need to improve the performance of the supporting host. Therefore, spring products play an important role in the development of the entire national industry. The daily necessities industry and hardware industry, including lighters, toys, locks, door hinges, fitness equipment, mattresses, sofas, etc., have the largest demand for springs in terms of quantity, tens of billions of pieces, with low technical requirements and very high prices. Low, generally produced by small spring factories scattered all over the country, they have unique advantages in cost, and it is difficult for large spring factories to compete with them. As a result, new spring companies are born from time to time. In the future, the market demand will grow at an annual rate of 7% to 10%. After China’s entry into the WTO, the export volume of daily hardware products has increased significantly, and the demand for springs has been driven. However, due to the impact of international market demand and trade barriers, the international market has its uncertain side. 
F=kx, F is the elastic force, k is the stiffness coefficient (or stubborn coefficient), and x is the length of the spring stretched (or compressed). Example 1: When a spring with a stiffness coefficient of 100N/m is pulled with a force of 5N, the spring is stretched by 5cm. Example 2: When a spring is subjected to a tensile force of 10N, the total length is 7cm, and when it is subjected to a tensile force of 20N, the total length is 9cm, what is the force when the original length and elongation are 3cm?
According to the nature of the force, springs can be divided into tension springs , compression springs , torsion springs and bending springs. According to the shape, they can be divided into disc springs , annular springs , leaf springs , coil springs, truncated cone scroll springs and torsion bar springs , etc. , According to the production process, it can be divided into cold coil springs and hot coil springs. Ordinary cylindrical springs are the most widely used because of their simple manufacture, various types of springs according to the load conditions, and simple structure. Generally speaking, the manufacturing material of spring should have high elastic limit, fatigue limit, impact toughness and good heat treatment performance. Commonly used are carbon spring steel, alloy spring steel , stainless spring steel and copper alloy, nickel alloy and rubber. Wait. The manufacturing methods of springs include cold rolling and hot rolling. The diameter of the spring wire is less than 8 mm, and the cold rolling method is generally used, and the hot rolling method is used for the spring wire larger than 8 mm. Some springs are subjected to strong pressure or shot peening after being made , which can improve the bearing capacity of the spring. 
Springs can be divided into the following 6 categories:
1. The torsion spring is a spring that bears torsional deformation, and its working part is also tightly wound into a spiral. The end structure of the torsion spring is a torsion arm machined into various shapes, not a shackle. The torsion spring uses the lever principle to twist or rotate the elastic material with soft material and high toughness, so that it has great mechanical energy. 2. The extension spring is a coil spring that bears the axial tension. When not under load, the coils of the tension spring are generally tight and there is no gap between the coils. 3. The compression spring is a coil spring that is subjected to axial pressure. The cross-section of the material used is mostly circular, and it is also made of rectangular and multi-strand steel yam. The spring is generally of equal pitch. The shape of the compression spring is: cylindrical Shape, conical, convex and concave shape and a small amount of non-circular, etc., there will be a certain gap between the rings of the compression spring, when the spring is subjected to external load, the spring shrinks and deforms, and the deformation energy is stored. 4. Progressive spring, this kind of spring adopts the design of inconsistent thickness and density. The advantage is that when the pressure is not large, it can absorb the ups and downs of the road surface through the part with lower elastic coefficient to ensure the riding comfort. When the pressure increases to After a certain degree, the thicker part of the spring plays the role of supporting the body, and the disadvantage of this kind of spring is that the control experience is not direct and the accuracy is poor. 5. Linear spring, the thickness and density of the linear spring from top to bottom are unchanged, and the elastic coefficient is a fixed value. The spring of this design can make the vehicle obtain a more stable and linear dynamic response, which is beneficial to the driver to better control the vehicle. It is mostly used for performance-oriented modified vehicles and competitive vehicles. The disadvantage is of course that the comfort is affected. 6. Short spring The short spring is shorter than the original spring, and more 
Sturdy and short springs are installed, which can effectively lower the center of gravity of the body, reduce the roll generated during cornering, make cornering more stable and smooth, and improve the vehicle’s cornering maneuverability. The damping setting of the original shock absorber is more comfortable, so the short spring and the original shock absorber are not very stable in cooperation. It cannot effectively suppress the rebound and compression of the short spring. When driving on bumpy roads, it will There is an uncomfortable jumping feeling. If things go on like this, the life of the shock absorber will be greatly shortened, and there may be oil leakage. Of course, the above conditions are relatively speaking. There will be no such serious damage in daily driving, and try not to drive vigorously. After all, the original shock absorber cannot withstand the pressure of high load. 
The torsion spring ( torsion spring ) uses the principle of the lever to twist or rotate the elastic material with soft material and high toughness, so that it has great mechanical energy. It is a spring that is subjected to torsional deformation, and its working part is also tightly surrounded or separated. The end structure of the torsion spring is processed into various shapes of torsion arms, from single torsion to double torsion, and even the deformation of various torsion bars, which can be shaped according to the design. Torsion springs are often used in balancing mechanisms in machinery, and are widely used in industrial production such as automobiles, machine tools, and electrical appliances. 
Compression springs ( compression springs ) are coil springs that are subjected to axial pressure. Springs are generally divided into equal-pitch springs and variable-pitch springs. The shapes of compression springs are: cylindrical, conical, convex and concave, and a small amount of Non-circular, etc., there is a certain gap between the rings of the compression spring, and the spring shrinks and deforms when subjected to an external load, storing deformation energy. Variable-pitch springs are becoming more and more common, not just equal-pitch springs, variable-pitch springs can play different roles in different environments. 
Carbon nanotube springs can be hundreds of microns in diameter and several centimeters in length . , field emission sources, energy dissipating fibers and other fields, it provides the possibility to prepare carbon nanotube electronic devices visible to the naked eye, and is also expected to be used in medical devices, such as tension sensing bandages. This new structure can also be developed into multifunctional carbon nanotube fiber composites. 
The extension spring ( tension spring ) is a helical spring that bears the axial tension, and the extension spring is generally made of circular section material. When not under load, the coils of the tension spring are generally tight and there is no gap between the coils. Using the stretched resilience (pulling force) to control the movement of parts, store energy, measure the size of the force, etc., it is widely used in machines and instruments. The hooks are in the form of side hook tension springs, long hook tension springs, English hook tension springs, German hook tension springs, semicircular hook tension springs, duckbill hook tension springs, etc. The materials are stainless steel, piano steel, high carbon Steel, phosphor bronze, beryllium copper, oil tempered alloy spring steel , etc. 
Air spring is a kind of non-metallic spring that adds pressurized air into a flexible airtight container and uses the compressibility of air to achieve elastic effect. It can be roughly divided into two types: capsule type and membrane type. In the suspension device of high-end vehicles, the ride comfort of the vehicle can be greatly improved, thereby greatly improving the comfort of the vehicle operation, so the air spring has been widely used in automobiles and railway locomotives. In addition, because air springs have many advantages compared with ordinary steel springs, they are also used in some mechanical equipment, precision instruments, 
As an important component in the industrial system, the spring has a large amount of use and a wide variety of types. Therefore, the production of the spring is gradually automated from the original manual production. Ninety years ago in China, there were only a few mechanical equipment specialized in producing springs in the spring industry. Ding), Guanghong (KHM), etc. gradually occupied the mainstream spring production market. Northeast EN502 universal machine 
Spring manufacturing equipment is the use of a proprietary mechanical mechanism, convenient and efficient production of various springs, special-shaped elastic elements. Guanghong’s equipment is a high-speed equipment for the production of compression springs and tension springs. There are also many professional spring equipment manufacturers abroad such as Wafios, MEC (now ORII&MEC) and so on. The domestic production of large-scale spring CNC hot rolling machines is still blank. Although the spring industry is a small industry in the entire manufacturing industry, its role cannot be underestimated. The expansion of spring production and sales scale, the increase of varieties, and the improvement of quality level are also the needs of the replacement of mechanical equipment and the need to improve the performance of the supporting host. Therefore, spring products have played an important role in the development of the entire national industry. Since the reform and opening up, with the globalization of the economy and the establishment of China’s status as a major manufacturing country, the demand for spring accessories has surged. In addition, the investment in spring production is not high, the technical threshold is low, and the investment recovery is fast. Since the 1980s, the number of spring production enterprises has increased rapidly. By the end of  2010, the domestic enterprises above designated size engaged in the spring manufacturing industryThere are 724 companies with more than 100,000 employees. In 2010, the sales revenue exceeded 30 billion yuan, and the total profit exceeded 1.6 billion yuan. Spring is a very competitive product. In the market, domestic enterprises with low-end products have cost advantages and certain price competitiveness, high-end products have advantages in foreign capital and joint venture technology, and cutting-edge products, such as elasticity for the treatment of cardiovascular diseases Stents are almost entirely monopolized by foreign medical giants, and domestic companies do nothing. Auto spring is the most fierce competition in the market between domestic and foreign companies. Domestic and foreign companies have their own advantages and are inseparable from each other. The spring industry has gradually entered the competition of the industrial chain from the price war and service competition in the past, and the industrial chain is completed by standardized means. Although the industry’s standard system is relatively complete, due to its early formulation, there is a considerable gap in market demand, especially compared with developed countries such as Japan, Europe, and the United States, the current national and industry standards are still relatively low, resulting in domestic The competitiveness of China’s spring products in the international market is not strong. Therefore, the introduction of new industry standards that are in line with international standards as soon as possible is the primary problem that the industry needs to solve. During the “Twelfth Five-Year Plan” period, thanks to the relevant national policy stimulus and the revitalization plan of related industries, my country’s automobile, railway, instrumentation and other industries will maintain rapid and stable development. In addition, some emerging industries such as conventional weapons, nuclear power and aircraft manufacturing are indispensable for the participation of springs. With the growing national strength of China, the investment in national defense science and technology is becoming more and more abundant, which is also an important aspect of the business opportunities in the spring industry. Under the background of a good external environment and steady growth of downstream demand, my country’s spring industry will maintain rapid and stable development. 
1) One-time automation capability of cold forming process. The cold forming machine has been developed to 12 jaws. Steel wires in the range of (0.3 to 14) mm can be formed at one time in the 8-jaw forming machine. Development direction of forming process equipment: ① Improve the forming speed, the main development trend is to improve the forming speed of the equipment, that is, the production efficiency; ② Improve the durability of the equipment by improving the precision of the equipment parts and strengthening the heat treatment effect; ③ Increase the length sensor and Laser range finder to stop automatic closed- loop control of the manufacturing process for CNC forming machines . 2) The ability of cold forming process. Large wire diameter spring coiling machine, the maximum size can reach 20mm, =2000MPa, the winding ratio is 5. There are still limitations in the cold forming process of reducing or equal diameter Minic-Block springs and eccentric springs. 
1) Hot forming process speed ability. In our country, there is only CNC 2-axis hot coil spring machine for forming on the (9~25) mm specification, with a maximum speed of 17 pieces per minute. Compared with prosperous countries, the gap is large. 2) Large spring hot forming process control ability. Since there is only a CNC 2-axis hot coil spring machine, the shape control is less effective in three directions, and the accuracy is poor; and there is no automatic bar rotation control and adjustment mechanism, so the degree and ability of the hot coil spring forming process are low. Therefore, the accuracy of the spring and the degree of oxidative decarburization of the surface are also low. 
The main function
①Control the movement of machinery, such as valve springs in internal combustion engines , control springs in clutches, etc. ② Absorb vibration and impact energy, such as buffer springs under automobiles and train carriages, vibration- absorbing springs in couplings , etc. ③ Store and output energy as power, such as clock springs, springs in firearms, etc. ④Used as a force measuring element, such as a force measuring device, a spring in a spring balance, etc. The ratio of the load to the deformation of the spring is called the spring stiffness, and the higher the stiffness, the stiffer the spring. The spring is an elastic element widely used in the mechanical and electronic industries. The spring can produce a large elastic deformation when it is loaded , and convert the mechanical work or kinetic energy into deformation energy. After unloading, the deformation of the spring disappears and returns to its original state. Deformation energy is converted into mechanical work or kinetic energy . 
We know that within the elastic limit , the extension (or contraction) of the spring is proportional to the external force. A spring balance is made using the property of a spring. 
The spring is deformed under the action of external force, and after the external force is removed, the spring can return to its state. Many tools and equipment use this property of springs to reset. For example, many building doors have return springs on the hinges that automatically reset when people enter or exit. People also use this function to make automatic umbrellas, automatic pencils and other supplies, which are very convenient. In addition, various buttons and keys are also indispensable for the return spring. 
Mechanical clocks, clockwork toys are driven by winding the clockwork. When the spring is wound up, the spring is bent and deformed, storing a certain amount of elastic potential energy . After the release, the elastic potential energy is converted into kinetic energy , which is driven to rotate by the transmission device. One of the properties of springs is also used in toy guns and starting guns and military firearms. 
A spring is installed between the locomotive frame and the wheel, and the elasticity of the spring is used to slow down the bumping of the vehicle. 
When air flows from the reed hole in a harmonica, accordion, it strikes the reed, and the reed vibrates to make a sound. 
Observing various electrical switches, you will find that one of the two contacts of the switch must be equipped with a spring to ensure that the two contacts are in close contact and are well connected. If the contact is poor, the resistance at the contact will increase, and the heat generated when the current passes through will increase. In severe cases, the metal at the contact will melt. The two metal columns of the bayonet lamp holder are equipped with springs for good contact; as for the central metal sheet of the screw base and the socket metal sheets of all sockets are reeds, their function is to make the two sides in close contact to keep the Same as good. In the cassette tape, there is a phosphor bronze reed, which uses the elastic force generated when it is bent and deformed to make the magnetic head in close contact with the tape. There is a long coil spring in the stapler. Its function is to hold the staples tightly, and on the other hand, when the front staple is pushed out, the back staple can be sent to the front to prepare the staple to be pushed out comfortably. In this way, the nails can be automatically pushed to the front until all the nails are pushed out. Many machines are self-feeding, and the automatic loading of bullets in automatic rifles relies on this function of the spring. In addition, clips like clips for clothes , ballpoint pens , and clips on pen sleeves all use the pressing function of springs to clip onto clothes. 
There are various specifications of spring tension and compression testing machines , spring fatigue testing machines , physical and chemical metallographic analysis, flaw detection equipment of different specifications, material torsional tensile testing machines, etc.
Pay attention to the problem
Due to the limitation of product structure, multi-strand springs generally have the characteristics of high strength and good performance. The material is required to guarantee the final performance in terms of spring strength and toughness. In the process of processing multi-strand springs, it should be noted that: 1. According to the product requirements, the support ring can choose two methods: cold and hot. It is not allowed to heat the spring until it sparks or turns white, and the temperature of the silicon-manganese steel shall not be higher than 850℃. The support ring and the effective ring should be in effective contact, and the gap should not exceed 10% of the nominal gap between the rings. 2. The characteristics of the multi-strand spring can be determined by adjusting the lead, and the cable distance can be adjusted when winding. The screw distance can be 3~14 times the diameter of the steel wire, but generally 8~13 times is better. The spring force is also closely related to the free height, the end ring, the outer diameter and the performance of the steel wire, which can be changed by adjusting one or more of them. 3. Springs without support rings and springs with too thin wire diameter should not be welded with spring heads, but the wire ropes at the ends should not have obvious looseness and should be deburred. For multi-strand springs whose head needs to be welded, the length of the welded part should be less than 3 times the cable diameter (the longest is not more than 10 mm). The heating length should be less than one circle, and it should be polished smooth after welding. During gas welding, the welding part should be partially annealed at low temperature. 4. The surface treatment of the spring is generally phosphating, and other treatments are also possible. Where the coating is zinc and cadmium, the hydrogen removal treatment should be carried out after electroplating. After the hydrogen removal, 3% (no less than 3 pieces) should be pumped for retesting and standing treatment, and there should be no breakage during the retesting. The surface of the spring should be cleaned of dirt, salt marks, and oxide skin. The method can be cleaned by sand blowing or gasoline, but pickling cannot be used. 5. The compression time of important springs is 24 hours, and the compression time of ordinary springs is 6 hours or 3 to 5 times continuously, and each time is kept for 3 to 5 seconds. When pressing, the gap between the spring and the mandrel should be 10% of the diameter of the mandrel. If the gap is too small, it will be difficult to operate, and if the gap is too large, the spring will be easily bent and deformed. If one of the springs is broken during compression, the rest should be reprocessed.