A spring is a mechanical part that works by elasticity. Generally made of spring steel. It is used to control the movement of machine parts, mitigate impact or vibration, store energy, measure the magnitude of force, etc., and is widely used in machines and instruments. According to the shape, there are mainly spiral springs, scroll springs and plate springs.
[ Edit this paragraph] Its main function
① Control the movement of machinery, such as valve springs in internal combustion engines and control springs in clutches. ② Absorb vibration and impact energy, such as buffer springs under cars and train carriages, vibration-absorbing springs in couplings, etc. (3) store and output energy as power, such as clock springs and springs in firearms. ④ Used as a force measuring element, such as a dynamometer, a spring in a spring scale, etc. The ratio of load to deformation of a spring is called spring stiffness. The greater the stiffness, the harder the spring is.
springs can be divided into tension springs, compression springs, torsion springs and bending springs according to their mechanical properties, and disc springs, ring springs, plate springs, spiral springs, truncated cone scroll springs and torsion bar springs according to their shapes. Ordinary cylindrical springs are widely used because of their simple manufacture and simple structure, which can be made into various types according to the load. Generally speaking, the manufacturing materials of springs should have high elastic limit, fatigue limit, impact toughness and good heat treatment performance, etc. Carbon spring steel, alloy spring steel, stainless spring steel, copper alloy, nickel alloy and rubber are commonly used. The manufacturing methods of springs include cold coil method and hot coil method. Generally, the diameter of spring wire is less than 8 mm by cold rolling method, and it is more than 8 mm by hot rolling method. Some springs have to be pressed or shot peened after being made, which can improve the bearing capacity of the springs.
the spring is a kind of elastic element widely used in the mechanical and electronic industries. When it is loaded, it can produce large elastic deformation, transforming mechanical work or kinetic energy into deformation energy. After unloading, the deformation of the spring disappears and returns to its original state, transforming the deformation energy into mechanical work or kinetic energy.
[ Edit this paragraph] Types of springs
According to the stress properties, springs can be divided into tension springs, compression springs, torsion springs and bending springs; According to the shape, it can be divided into disc spring, ring spring, plate spring, spiral spring, truncated cone scroll spring and torsion bar spring. Ordinary cylindrical springs are widely used because of their simple manufacture and simple structure, which can be made into various types according to the load. Generally speaking, the manufacturing materials of springs should have high elastic limit, fatigue limit, impact toughness and good heat treatment performance, etc. Carbon spring steel, alloy spring steel, stainless spring steel, copper alloy, nickel alloy and rubber are commonly used. The manufacturing methods of springs include cold coil method and hot coil method. Generally, the diameter of spring wire is less than 8 mm by cold rolling method, and it is more than 8 mm by hot rolling method. Some springs have to be pressed or shot peened after being made, which can improve the bearing capacity of the springs.
what is a coil spring?
The helical spring is a torsion spring, which bears torsion deformation, and its working part is also tightly wound into a spiral. The end structure of the torsion spring is a torsion arm processed into various shapes, not a hook. Torsion spring is often used in the balance mechanism of machinery, and is widely used in industrial production such as automobiles, machine tools and electrical appliances.
what is a tension spring?
Tension springs are spiral springs that bear axial tension. Generally, tension springs are made of circular cross-section materials. When not under load, the coils of the tension spring are generally tight without gap.
what is a compression spring?
compression spring is a spiral spring that bears the axial pressure. Its cross section is mostly circular, and it is also made of rectangular and multi-strand steel. Springs are generally of equal pitch. The shapes of compression springs are: cylindrical, conical, convex and concave, and a small amount of non-circular. There is a certain gap between the coils of compression spring. When subjected to external load, the spring contracts and deforms to store deformation energy.
what is a torsion spring? The torsion spring uses the lever principle to twist or rotate the elastic material which is soft and tough, so that it has great mechanical energy.
[ Edit this paragraph] Name of each part of the spring:
(1) Diameter of spring wire D: diameter of steel wire for making the spring.
(2) outside diameter d of the spring: the maximum outside diameter of the spring.
(3) inner diameter D1 of the spring: the minimum outer diameter of the spring.
(4) Middle diameter D2 of the spring: the average diameter of the spring. Their calculation formula is: D2 = (d+D1) ÷ 2 = D1+D = D-D < P > (5) t: Except for the support ring, the axial distance between the corresponding points of two adjacent coils of the spring on the middle diameter becomes the pitch, which is expressed by t..
(6) effective turns n: the number of turns that the spring can keep the same pitch.
(7) Number of support rings n2: In order to make the spring bear uniform force during work and ensure that the axis is vertical to the end face, the two ends of the spring are often tightened during manufacture. The number of tight turns only plays a supporting role, which is called a supporting ring. Generally, there are 1.5T, 2T and 2.5T, and 2T is commonly used.
(8) total number of laps n1: the sum of effective laps and supporting laps. That is, n1=n+n2.
(9) Free height H: the height of the spring without external force. Calculated by the following formula: H=nt+(n2-.5)d=nt+1.5d (n2=2)
(1) spring deployment length l: the length of steel wire required for winding the spring. L ≈ n1 (л d2) 2+N2 (compression spring) L = л d2n+hook development length (tension spring)
(11) Spiral direction: there are left and right rotations, usually right-handed, and right-handed if not specified in the drawing.
(12) spring winding ratio; The ratio of the middle diameter d to the steel wire diameter d
[ edit this paragraph] The specified drawing method of the spring
(1) On the view parallel to the spiral spring line, the contour lines of each circle are drawn as straight lines.
(2) For a spring with more than 4 effective turns, only 1-2 turns (excluding the support ring) can be drawn at both ends. The middle is connected by a dotted line passing through the center of the spring steel wire.
(3) In the pattern, when the rotation direction of the spring is not specified, all spiral springs are drawn as right-handed, and left-handed springs are also drawn as right-handed, but the word "left" should be marked.
[ Edit this paragraph] Application of Spring
Most materials have different degrees of elasticity, and if they are bent, they will return to their original shape with great force. In human history, it must have been noticed that the branches of saplings and young trees are very flexible, because many primitive cultures use this characteristic to wedge a stick behind a special door or cage, or pull it down with a slipknot on a rod; Once the tension is released, the stick or rod will bounce back. This is how they catch birds and animals. In fact, the bow is a spring that uses the elasticity of young trees in this way; Pull the bow back first, then let it go and let it rebound. In the Middle Ages, this idea began to appear on machinery, such as textile machines, lathes, drilling machines, grinding machines and saws. The operator gives a downward stroke with his hand or pedal to pull down the working machine. At this time, a rod fixed on the machine with a rope bounces back and produces reciprocating motion.
the torsion resistance of an elastic material is not dependent on its flexibility. During the period of the Greek Empire (probably in the 4th century BC), a torsion spring was invented, which was tensioned with twisted tendon or wool rope, instead of a simple spring, to strengthen the power of stone crossbows and stone throwers. At this time, people began to realize that metal is more elastic than wood, keratin or any such organic substance. Philo (who wrote about 2 BC) introduced it as a new discovery. He estimated that the readers were unbelievable. The flexibility of Celtic and Spanish swords attracted the attention of his predecessors in Alexandria. In order to find out why Chu Jian is elastic, they conducted many experiments. As a result, his master, Ketcibi, invented the trebuchet. The spring of the trebuchet was made of a bent bronze plate-in fact, it was the earliest leaf spring. Philo himself further improved these trebuchets. After inventing this kind of trebuchet, the creative Kertesby came up with another kind of trebuchet-it uses the elasticity generated by the air in the cylinder under pressure.
it took a long time for people to think that if a spiral rod is compressed instead of bending a straight rod, the energy stored in a metal spring will be greater. According to Filippo Brwnelle-Schi's biography, he made an alarm clock, in which several generations of springs were used. Recently, it was pointed out that there was a pattern of this alarm clock in a mechanical manual at the end of the 15th century with some peculiar spiral spring clocks. This kind of spring is also used in modern mousetraps. Clocks and watches with coil springs (springs compressed horizontally rather than vertically) must have been used around 146, but they were basically luxury items of the royal family. It took about another century for clocks and watches with springs to become the symbol of the middle class.
valve to control the flow direction
Because the valve only allows water or other fluids (such as air) to flow in one direction, it is almost certain that it first appeared as a part of the bellows, an early tool that needed this movement. Agricola said in an article on metallurgy during the Renaissance that the bellows of the forge iron furnace has a thin plate slightly longer and wider than the eye of the wind. "The thin plate is covered with goatskin, which is tied to the plate with a belt, and the burr side rushes to the ground." The way of placing is: when the bellows bulges, the thin plate opens; When the bellows contracts, the thin plate closes. "Flap valve must be much earlier than agricola's time, as old as wedge bellows. However, it is difficult to determine the exact date when it came out, because the term flap valve comes from the ancient leather bag bellows (in which the operator can block the eye with his feet or hands). Obviously, the earliest model was about the bronze lamp in the Greek dynasty, but no one had mentioned the valve of the bronze lamp before Ausunius, a poet in late Rome. Asszonyi uz put the gills of dying fish on land. It is compared to a wool valve that alternately enters the air and blocks the wind through holes when reciprocating in the wood cavity.
It can be said that the history of using valves in machinery started from the pressure pump in Sibi, Ueckert. Vitoravis and Herod gave a detailed explanation of the pressure pump. They said: "The annular thin sheet skillfully installed in the pipe mouth will not let the things pressed into the container run back." It seems that the original flap valve of Ketcibi pressure pump is long and cylindrical, which has been used to ventilate the roof at that time. Later, a rectangular valve was used, but the name remained unchanged. Several Roman pressure pumps have been repaired, and their valves have been seriously corroded, but they can still be identified. When Heron talked about using a double-cylinder pressure pump as a fire extinguisher, he also introduced a primitive jumping valve, some small disks sliding up and down on three bent columns. The hydraulic machinery of Ketcibi has a slide valve to control air entering the pipeline. In addition, before the Renaissance, all pumps and bellows valves were flap valves (or hinge valves).
A kind of conical beating flapper invented by Leonardo da Vinci is undoubtedly the source of those flappers drawn in Ramelli's mechanical invention manual
(1588). Aleotti, a contemporary of Ramelli, used a butterfly valve to control the water flow in the pipeline in the automatic puppet show. However, from the time of Heron until the invention of the steam engine, none of these beating flappers were widely used, and there was no change in various valves. The steam engine (which needs to control the inflow and outflow sequence more accurately) has led to the emergence of precise valves related to the operation of the engine, including the "jet valve" designed by newcomen to release the air accumulated in the cylinder, Murdoch's slide valve (1799) and the balance valve to keep the piston of the double-acting engine balanced.
air pump
Gerik, the mayor of Madeborg, Germany, is very interested in the debate between scientists and philosophers about the possibility of forming a vacuum. As a specially educated engineer, he decided to solve this problem through experiments. In 165, he made the first air pump-like a hand-operated water pump, but with precision parts, it was airtight. This air pump is a success. He pointed out that in a container with exhausted air, no bells can be heard, no candles will burn, and animals will suffocate.
His large-scale demonstration was spectacular. One experiment was carried out in the open space in front of the court in front of Emperor Ferdinand III. In this experiment, the peripheral flanges of two hemispheres with a diameter of 12 feet were coated with grease, the flanges of the two hemispheres were embedded, and then the air in the sphere was exhausted. Eight horses were divided into two groups, and the cables tied to each hemisphere failed to separate them, but they separated after being released into the air. In another experiment in 1654, a vacuum was pumped under a vertical open cylinder piston, and 5 people pulled the rope tied to the piston, but they were pulled by the piston. People use this method to make the piston do work; There must always be a vacuum under the piston.
But can a vacuum be created without an air pump? After many years, people found that steam can solve this problem. In 1698 AD, Thomas savery was the first to use steam to drain water, so that the steam was introduced into a closed container, and then cold water was sprayed on the container to condense the steam, thus creating a vacuum. He used this vacuum to pump water from the mine and used boiler steam to empty the water in the container. This cycle is repeated.
savery's equipment is called "Friends of Miners". It doesn't have any pistons or moving parts, nor is it an engine, but it is just a pump.
Before that, in 169, dennis Papin had made a model device, and a piston with a diameter of 2.5 inches could just fit into the cylinder. With a small amount of water in the cylinder, he can prove that a vacuum is formed under the piston when the cylinder cools by heating and cooling the water continuously. Although this kind of equipment has not been applied in practice, it is the first equipment that uses condensed steam to push the piston and do work.
in 1712, guericke, Papin and savery combined the above three achievements, and Thomas Newcomen of Dartmouth made a practical steam engine.
Hook invents the universal joint
In 1676 AD, robert hooke, who is known as "Da Vinci of England", delivered his speech on
"Sunglasses". This is an instrument that uses a mirror system to observe the sun safely. This instrument is operated with his novel universal joint. The universal joint is a universal instrument ... used to generate circular motion through any irregular curved track. Although Hooke talked about the manufacturing method of this new instrument in detail and vaguely pointed out that this instrument may be applied in various aspects, he only wanted to use it for astronomical observation or in the design of clocks and heliostats, so it did not attract much attention at that time.
Hook is a brilliant man. While systematically putting forward revolutionary theories in physics, chemistry and geology, he made endless discussions with like-minded friends in London cafes, and found time to make more than twenty inventions. His diary usually mentions a little how some new ideas are gradually brewing in his highly active mind. The proceedings of the Royal Society recorded the experiments that made his latest discovery famous.
However, the diary doesn't say that he spent a lot of time on the universal joint; He never wanted to learn how to demonstrate universal joints.