Springs are mechanical parts that work by elasticity. Usually made of spring steel. It is used to control the movement of machine parts, reduce impact or vibration, store energy, measure the force, etc. , widely used in machines and instruments. According to the shape, there are mainly spiral springs, scroll springs and leaf springs.
[Edit this paragraph] Its main functions
① Control the movement of machinery, such as valve spring in internal combustion engine and control spring in clutch. (2) Absorb vibration and impact energy, such as buffer springs under cars and trains, damping springs in couplings, etc. (3) storing and outputting energy as power, such as clock springs and springs in firearms. ④ Used as force measuring elements, such as dynamometers and springs in spring scales. The ratio of spring load to deformation is called spring stiffness. The greater the stiffness, the harder the spring.
Springs can be divided into tension springs, compression springs, torsion springs and bending springs according to their mechanical properties, and can be divided into disc springs, ring springs, leaf springs, spiral springs, truncated cone scroll springs and torsion bar springs according to their shapes. Ordinary cylindrical springs can be made into various types according to the load because of their simple manufacture, simple structure and wide application. Generally speaking, the spring manufacturing materials should have high elastic limit, fatigue limit, impact toughness and good heat treatment performance. Commonly used are carbon spring steel, alloy spring steel, stainless steel spring steel, copper alloy, nickel alloy, rubber and so on. The manufacturing methods of springs include cold coil method and hot coil method. Generally, the diameter of spring wire by cold rolling method is less than 8 mm, and that by hot rolling method is greater than 8 mm. Some springs must be punched or shot peened after being made, which can improve the bearing capacity of the springs.
Spring is an elastic element widely used in mechanical and electronic industries. When it is loaded, it can produce large elastic deformation and convert mechanical work or kinetic energy into deformation energy. After unloading, the deformation of the spring disappears and returns to its original state, and the deformation energy is converted into mechanical work or kinetic energy.
[Edit this paragraph] Spring class
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, leaf spring, spiral spring, frustum scroll spring and torsion bar spring. Ordinary cylindrical springs can be made into various types according to the load because of their simple manufacture, simple structure and wide application. Generally speaking, the spring manufacturing materials should have high elastic limit, fatigue limit, impact toughness and good heat treatment performance. Commonly used are carbon spring steel, alloy spring steel, stainless steel spring steel, copper alloy, nickel alloy, rubber and so on. The manufacturing methods of springs include cold coil method and hot coil method. Generally, the diameter of spring wire by cold rolling method is less than 8 mm, and that by hot rolling method is greater than 8 mm. Some springs must be punched or shot peened after being made, which can improve the bearing capacity of the springs.
What is a coil spring?
The helical spring, that is, the torsion spring, is a spring that bears torsional deformation, and its working part is tightly wound into a spiral shape. The end structure of the torsion spring is a torsion arm processed into various shapes, not a hook. Torsion springs are commonly used in mechanical balancing mechanisms and are widely used in industrial production such as automobiles, machine tools and electrical appliances.
What is a tension spring?
Tension spring is a spiral spring that bears axial tension and is generally made of circular cross-section material. When there is no load, the coil of the tension spring is usually tight and there is no gap.
What is a compression spring?
The compression spring is a spiral spring that bears axial pressure. The cross section of the materials used is mostly round, but also rectangular and multi-strand steel. Springs are usually equally spaced. The shapes of compression springs are cylindrical, conical, convex and concave, and a few are non-circular. There is a certain gap between the coils of the compression spring. When subjected to an external load, the spring contracts and deforms to store deformation energy.
What is a torsion spring? Torsion spring uses lever principle to twist or rotate soft and tough elastic material, which makes it have great mechanical energy.
[Edit this paragraph] Spring part name:
(1) spring steel wire diameter d: the diameter of steel wire used for making springs.
(2) Outer diameter d of the spring: the maximum outer diameter of the spring.
(3) Inner diameter of the spring D 1: the minimum outer diameter of the spring.
(4) The middle diameter of the spring D2: the average diameter of the spring. Their formula is: D2 = (d+d1) ÷ 2 = d1+d = d-d.
(5)t: Except for the support ring, the axial distance between the corresponding points of two adjacent coils of the spring on the pitch diameter is the pitch, which is expressed by T. ..
(6) Effective number of 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 perpendicular to the end face, both ends of the spring are often tightened during manufacture. The tight revolution only plays a supporting role, which is called the supporting ring. Generally, there are 1.5T, 2T and 2.5T, and 2T is commonly used.
(8) Total laps n 1: the sum of effective laps and supporting laps. That is, n 1=n+n2.
(9) Free height H0: the height of the spring without external force. According to the following formula: h0 = nt+(N2-0.5) d = nt+1.5d (when N2 = 2).
(10) spring deployment length l: the length of steel wire required for winding the spring. L ≈ n 1 (л d2) 2+N2 (compression spring) L =лd2n+ hook deployment length (extension spring)
(1 1) Spiral direction: there is left-right rotation, which is generally right-handed, and it is generally right-handed if not specified in the drawing.
(12) spring winding ratio; Ratio of middle diameter d to steel wire diameter d
[Edit this paragraph] The specified map of spring
(1) The outline of each circle is drawn as a straight line on the view parallel to the coil spring line.
(2) For springs with more than 4 effective turns, only 1 ~ 2 turns can be drawn at both ends (excluding the support ring). The middle is connected by a dotted line passing through the center of the spring steel wire.
(3) In the drawing, 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 the application of spring in this paragraph.
Most materials have different degrees of elasticity. If they are bent, they will return to their original state with great force. In human history, someone must have noticed that the branches of saplings and young trees are very flexible, because many primitive cultures use this feature to wedge a stick behind a special door or cage or pull it down with a slipknot on a pole; 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, which is how to use the elasticity of small trees; Pull the bow back first, then let it go and let it bounce. In the Middle Ages, this idea began to appear on machines, such as textile machines, lathes, drilling machines, grinders and saws. The operator draws down 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 does not depend on its flexibility. During the Greek Empire (probably in the 4th century BC), a torsion spring was invented, which was tightened with twisted tendons or wool ropes instead of simple springs to strengthen the strength of stone crossbows and trebuchets. At this time, people began to realize that metals are more elastic than wood, keratin or any such organic substances. Philo (who wrote about 200 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 flexible, they conducted many experiments. So his master, Ketchibi, invented the trebuchet. The spring of the trebuchet is made of a bent bronze plate-in fact, this is 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 elastic force generated by the air in the cylinder under pressure.
It took a long time for people to think that metal springs would store more energy if they compressed the spiral rod instead of bending the straight rod. 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 a mechanical manual at the end of 15 has the pattern of this alarm clock with some strange spiral spring clocks. This kind of spring is also used in modern mousetraps. Clocks and watches with spiral springs (springs are compressed horizontally instead of vertically) must have been used around 1460, but they are basically royal luxury goods. It was about 1 century before the clock with spring became a symbol of the middle class.
Valve for controlling 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 originally appeared as a part of bellows, which is an early tool that needs this movement. Agricola said in an article about metallurgy in the Renaissance that the bellows of the forge furnace has a thin plate slightly longer and wider than the eye of the wind. "The sheet was covered with goatskin, tied to the board with a belt, and the burr side rushed to the ground." Placement method: when the corrugated pipe 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. But it is difficult to determine the exact date of its appearance, because the word flap valve comes from the ancient leather bag bellows (in which the operator can block his eyes with his feet or hands). Obviously, the earliest model was about the bronze lamp of the Greek dynasty, but before the late Roman poet Osunius, no one mentioned the valve of the bronze lamp. Asszonyi uz put the gills of dying fish on land. It is compared to a wool valve, which alternately enters the air and blocks the wind through the hole when reciprocating in the wood cavity.
It can be said that the history of mechanical use of valves began with Ueckert Sibi's pressure pump. Victoria Laves and Herod explained the pressure pump in detail. They said: "The annular thin sheet cleverly installed at the nozzle will not let the things pressed into the container run back." It seems that the original flap valve of the Ketchibi pressure pump was long and cylindrical, and it was 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 the 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 an original jump valve, in which some small disks slide up and down on three curved columns. Ketcibi's hydraulic machinery has a slide valve to control the air entering the pipeline. In addition, before the Renaissance, all pumps and bellows valves were flap valves (or hinge valves).
A cone-shaped jumping clapper invented by Leonardo da Vinci is undoubtedly Ramelli's mechanical invention manual.
(1588). Allehaut Ti, a contemporary of Ramelli, used butterfly valves to control the water flow in the pipeline in the automatic puppet show. But from the time of Heron until the invention of the steam engine, these flaps were not widely used, and various valves did not change. The steam engine (which needs to control the inflow and outflow sequence more accurately) leads to the emergence of precise valves related to the engine operation, including the "injection valve" designed by newcomen to release the air accumulated in the cylinder, Murdoch's slide valve (1799) and balance valve to keep the piston balance of the double-acting engine.
air exhauster
Gerik, the mayor of Madburg, Germany, is very interested in the debate between scientists and philosophers about the possibility of forming a vacuum. As an engineer with special education, he decided to solve this problem through experiments. 1650, he made the first air pump-like a manual water pump, but with precision parts, airtight. This air pump is a success. He pointed out that in a container with exhausted air, no bells can be heard, and animals will suffocate if candles don't burn.
His large-scale demonstration was spectacular. One of the experiments 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 are coated with grease, the flanges of the two hemispheres are embedded, and then the air in the sphere is 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. Another experiment in A.D. 1654 was to vacuum the bottom of a cylinder piston with a vertical opening and use 50 people to pull the rope tied to the piston. Instead, they are 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 formed without an air pump? Many years later, people found that steam can solve this problem. In A.D. 1698, Thomas savery was the first to drain water with steam, so that the steam was introduced into a closed container, and then cold water was sprayed on the container to condense the steam, thus forming a vacuum. He used this vacuum to pump water from the mine and emptied the water in the container with boiler steam. This cycle goes back and forth.
Savili'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.
Prior to this, in 1690, Frenchman Dennis Papin had made a model device, and a piston with a diameter of 2.5 inches could just fit into the cylinder. In the case of a small amount of water in the cylinder, he can prove that when the cylinder is cooled, a vacuum is formed under the piston by constantly heating and cooling the water. Although this kind of equipment has not been applied in practice, it is the first equipment that uses condensed steam to push the piston to do work.
17 12 years, Gehrig, Papin and Savili synthesized the above three achievements, and Thomas Newcomen of Dartmouth made a practical steam engine.
Hook invented the universal joint.
In A.D. 1676, robert hooke, known as "Da Vinci of England", published his book on.
"Sunglasses" speech. This is an instrument that uses a mirror system to observe the sun safely. This instrument is operated with his new universal joint. 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 used in various aspects, he only wanted to use it for astronomical observation or for the design of clocks and heliostats, so it did not attract much attention at that time.
Hook is a clever man. While systematically proposing revolutionary theories of physics, chemistry and geology, after endless discussions with like-minded friends in London cafes, he found time to make more than 20 inventions. His diary usually mentions how some new ideas are gradually brewing in his highly active mind. The Journal of the Royal Society recorded the experiment that made his latest discovery famous in the world.
However, the diary does not say that he spent a lot of time on the universal joint; He never wants to learn how to demonstrate the universal joint. As far as this machine is concerned, there is no doubt that this invention belongs entirely to him. But in terms of power transmission, before the traffic revolution in19th century, like many other inventions, there was no need for a free joint that could transmit in all directions.
Vala invented the governor.
The centrifugal governor used in the steam engine invented by Watt in 1789 did not cause much sensation at that time. Watt attaches importance to the power system and only regards the governor as an accessory on the steam engine. However, it is the first device to effectively control the speed by changing the fuel input, and it is the originator of all feedback devices that enable a machine to automatically adjust, and its position in the history of invention has been confirmed. Watt's governor consists of a pair of centrifugal pendulums, the farthest one of which is connected with the rotating flywheel of the steam engine and directly connected with the sleeve, which is connected with the steam inlet valve of the cylinder. When the flywheel speeds up, the two spheres swing outward, making the sleeve descend; When the speed slows down, the ball will sink and force the sleeve to rise. The steam valve can be adjusted up and down to maintain a constant speed.
The history of watt governor can be traced back to the ball chain device or club device used to replace the flywheel of the machine in the Middle Ages and Renaissance. However, these devices only play the role of flywheel. By storing energy, the drilling rig or crank moves regularly and drives the tools to cross the "dead point". They can't control the speed or power input, and can only stimulate the shape of the governor at most. It was not until the development of mechanics that people knew the performance of the pendulum and understood the centrifugal force that someone thought of using the club combination device to control it.
One of the problems that mill workers often encounter is that they can't take advantage of strong winds. Because when the rotation speed of important officials is very fast, the grindstone can easily move upward, which increases the distance between the two grindstones, so that the grain sandwiched between the two grindstones cannot be completely ground. People tighten two grindstones by hand to keep a proper distance between them. It wasn't until 1787 that Thomas Meade came up with a way to hang two pendulums on spur gears that drive grindstones, and lift the adjusting pull rod through chains and universal joints. The other pair of pendulums is connected with the wing plate of the windmill, so that the latter opens and closes with the change of speed. The milling machine can adjust the speed of the rotating shaft by changing the wind force on the wing plate. Two years later, Stephen Hooper replaced the chain with a rack and a sector gear, designed a competitive machine and obtained a patent.