齒輪傳動外文文獻翻譯、中英文翻譯、外文翻譯
齒輪傳動外文文獻翻譯、中英文翻譯、外文翻譯,齒輪,傳動,外文,文獻,翻譯,中英文
Gear
Gear (Gear) is relying on the tooth meshing torque rotavirus mechanical parts.Gear withother dentate machinery parts, such as a worm gear, rack, transmission, which can realize changedthe direction of rotation speed and torque, change the direction of movement and change themovement forms, and other functions.Owing to the high transmission efficiency, accurate andadvantages of large range of power transmission ratio, gear mechanism is widely used in industrialproducts, the design and manufacture level directly affects the quality of industrial products.Geartooth buckle each gear will drive the other gears to transmit power.?Separate two gears, chains canalso be applied, caterpillar, on both sides of the belt to drive gear and transmission power.
Basic introduction：
In the application of transmission gear appeared very early.More than three hundred years BC, theancient Greek philosopher Aristotle in the mechanical problems, it expounds the bronze or irongear transmission problem of rotary motion.?Invented in ancient China, has been applied in theentire gear train.However, the ancient gear is made of wood or metal moulds, can only transferbetween shaft rotary motion, cannot guarantee the stability of transmission, the bearing capacity ofthe gear are also small.According to historical records, in 400 ~ 200 BC in ancient China hasalready started to use gear, shanxi unearthed bronze gears in our country is by far the oldest gearhad been found, as a reflection of ancient science and technology achievements of this work is togear mechanism as the core mechanism.?The 1 7th century, people started to research, can bedelivered right tooth shape of the movement.The 18th century, Europe: after the industrialrevolution, the " application of_ gear .?transmission is inereasing day.?by day widely;First thedevelopment of cycloidal gear, then the involute gear, until the beginning of the 20th century,involute gear has set up a file in the application.
As early as 1694, the French scholar Philippe De La Hire first proposed that the involute can be used as the tooth curve.In 1733, a Frenchman named M. amus proposed that the common normal at the point of contact between teeth must pass through a node on the Central Line.When an auxiliary instantaneous center line rolls purely along the instantaneous center line (pitch circle) of the large wheel and the small wheel respectively, the two tooth profile curves formed by the auxiliary tooth profile fixed to the auxiliary instantaneous center line on the large wheel and the small wheel are conjugate to each other, which is Camus theorem.It considers the meshing state of two tooth surfaces.Definitely established the modern concept of the contact point trajectory.In 1765, L. Uler from Switzerland proposed the mathematical basis of the analytical study of involute tooth profile, and clarified the relationship between the radius of curvature and the position of the center of curvature of the tooth profile curve of a pair of gear meshing.Later, Savary_ further completed this method and became the present bu-let-savary equation.Contributed to the application of involute profile is Roteft Wulls, who proposed that the involute gear has the advantage of constant angular speed ratio when the center distance changes.In 1873, German engineer Hoppe proposed the involute tooth shape of gears with different tooth numbers when the pressure Angle was changed, which laid the ideological foundation of modern variable gear.
At the end of the 19th century, the development of the principle of gear cutting method and the use of this principle of gear cutting special machine tools and cutting tools have emerged, so that gear processing with a more complete means, the involute tooth profile shows a great advantage.As long as the gear cutting tool is slightly moved from the normal meshing position, the standard tool can be used to cut out the corresponding gear on the machine tool.In 1908, Switzerland MAAG studied the displacement method and manufactured the machining gear shaper machine. Later, the British BSS, the American AGMA and the German DIN successively put forward a variety of calculation methods for gear displacement.
In order to improve the service life of power transmission gear and reduce its size, besides improving the material, heat treatment and structure, the gear with circular tooth shape has been developed.In 1907, Frank Humphris, an Englishman, first published the circular tooth shape.In 1926, Eruest Wildhaber from Switzerland obtained the patent right of normal circular arc helical gear.In 1955, M. L. Novikov of the Soviet Union completed a practical study of circular tooth gear and was awarded the Order of Lenin.In 1970, engineer R. M. Studer of Rolh-Royce Company of the United Kingdom received a U.S. patent for a double circular arc gear.This kind of gear has been paid more and more attention by people, and has produced remarkable benefits in production.
Gear is a kind of mechanical parts with teeth that can engage with each other.?It is widely used in mechanical transmission and the whole mechanical field.Modern gear technology has reached: gear module 0.?004~100 mm;Gear diameter from 1 mm to 150 meters;Transmitted power up to 100,000 kilowatts;Speed up to hundreds of thousands of revolutions/min;The maximum circumferential speed is 300 meters per second.
With the development of production, the smoothness of gear operation is valued.In 1674, the Danish astronomer Romer first proposed to use the epicycloid as the tooth profile curve to get a smooth running gear.
During the period of the industrial revolution in the 18th century, gear technology developed rapidly, and a great deal of research was done on gears.In 1733, the French mathematician Cami published the basic law of tooth profile meshing.In 1765, Swiss mathematician Euler suggested the use of involute tooth profile curve.
The hobbing machine and gear shaper machine that appeared in the 19th century solved the problem of mass production of high precision gear.In 1900, pouford for hobbing machine installed on the differential device, can be processed on the hobbing helical gear, hobbing gear has been popularized from then on, the development method plus 1 gear accounted for the overwhelming advantage, involute gear has become the most widely used gear.
In 1899, Lasher first implemented the modified gear scheme.The modified gear can not only avoid root cutting, but also match center distance and improve the bearing capacity of gear.In 1923, Wilder Haber of the United States first proposed the gear with circular arc tooth profile.?In 1955, Sunovikov conducted in-depth research on the circular arc gear, and the circular arc gear was then applied to the production.This kind of gear has high bearing capacity and efficiency, but it is not as easy to manufacture as the involute gear, so it needs further improvement.
Generally, there are gear teeth, tooth groove, end face, normal face, tooth top circle, tooth root circle, base circle, dividing circle.
Gear teeth, referred to as teeth, are each convex part of the gear used for meshing.?These convex parts are generally arranged in a radial manner.?The teeth on the matching gear are in contact with each other, which can make the gear continuously meshing;
(2) tooth slot, which is the space between two adjacent teeth on the gear;The end face is the plane on a cylindrical gear or worm that is perpendicular to the axis of the gear or worm
(3) Normal surface, refers to the plane perpendicular to the gear tooth line
(4) Tooth top circle refers to the circle where the top of the tooth is located
(5) The tooth root circle refers to the circle at the bottom of the groove
(6) the base circle, forming the involute line to make a pure rolling circle
(7) Indection circle is the reference circle for calculating the geometric dimension of the gear in the end face.
Gears can be classified according to tooth shape, gear shape, tooth line shape, tooth surface and manufacturing method.The tooth profile of a gear includes tooth profile curve, pressure Angle, tooth height and displacement.Involute gear is relatively easy to manufacture, so in the modern use of gear, the absolute majority of involute gear, and cycloidal gear and arc gear are less used.
In the aspect of pressure Angle, the bearing capacity of low pressure Angle gear is small.While the high pressure angular gear, although the bearing capacity is higher, but in the case of the same transmission torque bearing load increases, so it is only used in special cases.And the gear tooth height has been standardized, generally use standard tooth height.Modified gear has many advantages, has been widely used in all kinds of mechanical equipment.
In addition, gear can also be divided into cylindrical gear, bevel gear, non-circular gear, rack, worm and worm gear according to its shape;According to the shape of tooth line, it can be divided into straight gear, helical gear, herringbone gear and curve gear.According to the surface where the teeth are divided into outer gear, inner gear;According to the manufacturing method, it can be divided into casting gear, cutting gear, rolling gear, sintering gear and so on.
Manufacturing materials and heat treatment process of gears have great influence on the bearing capacity, size and weight of gears.Before the 1950s, the gear used carbon steel, the 1960s to change to alloy steel, and the 1970s used surface hardening steel.According to hardness, tooth surface can be divided into soft tooth surface and hard tooth surface two.
The gear bearing capacity of soft tooth surface is low, but it is easier to manufacture and has good running fit.?It is mostly used for transmission size and weight without strict restrictions, and for general machinery with small amount of production.In the paired gear, the small wheel bears a heavy burden, so in order to make the working life of the large and small gears roughly equal, the tooth surface hardness of the small wheel is generally higher than that of the large wheel.The bearing capacity of hard tooth gear is high.?It is quenched, surface quenched or carburized quenched after the fine cutting of the gear to improve the hardness.But in the heat treatment, the gear will inevitably produce deformation, so after the heat treatment must be grinding, grinding or fine cutting, in order to eliminate the error caused by deformation, improve the accuracy of the gear.
Material composition:
The steels commonly used in the manufacture of gears are tempered and tempered steels, hardened steels, carburized and hardened steels and nitriding steels.Cast steel has slightly lower strength than wrought steel and is often used for larger gear sizes.Gray cast iron has poor mechanical properties and can be used in light load open gear transmission.Ductile iron can partially replace steel to make gears.Plastic gear is mostly used for light load and low noise requirements, and its matching gear - generally with good thermal conductivity steel gear.
In the future, the gear is developing in the direction of heavy duty, high speed, high precision and high efficiency, and strives for small size, light weight, long life and economic reliability.
The development of gear theory and manufacturing technology will further study the mechanism of gear tooth damage, which is the basis of establishing a reliable strength calculation method, is to improve the bearing capacity of gear, prolong the theoretical basis of gear life;The new tooth profile represented by the circular arc tooth profile was developed.To study new gear materials and new gear manufacturing technology;The elastic deformation, manufacturing and installation errors and the distribution of temperature field of the gear are studied, and the gear tooth modification is carried out to improve the smooth operation of the gear, and the contact area of the gear teeth is increased at full load, so as to improve the bearing capacity of the gear.Friction, lubrication theory and lubrication technology are the basic work in gear research.studying the theory of elastohydrodynamic pressure lubrication, popularizing the use of synthetic lubricating oil and properly adding extreme pressure additives in the oil can not only improve the bearing capacity of the tooth surface, but also improve the transmission efficiency.
1, tooth surface wear
For open gear drive or closed gear drive containing unclean lubricating oil, due to the relative sliding between the meshing tooth surfaces, some hard abrasive particles enter the friction surface, so that the tooth profile changes, the backlash increases, so that the excessive thinning of the gear leads to tooth broken.Under normal circumstances, only when abrasive particles are included in the lubricating oil, abrasive wear on the tooth surface will be caused in operation.
2, tooth surface bonding
For high-speed and heavy-duty gear transmission, due to the greater friction between tooth surfaces and the high relative speed, the temperature in the meshing zone is too high.?Once the lubrication conditions are poor, the oil film between tooth surfaces will disappear, making the metal surfaces of the two teeth contact directly, thus mutual bonding occurs.When the two tooth surfaces continue to move relative to each other, the harder tooth surface will be softer tooth surface.The upper part of the material is torn off along the sliding direction to form grooves.
3, fatigue pitting
When two meshing teeth contact each other, the force and reaction force between the tooth surfaces cause contact stress on the two working surfaces.?Because the position of the meshing point is changing, and the gear moves periodically, the contact stress changes in a pulsating cycle.Under the action of this alternating contact stress for a long time, a small crack will appear at the cutter mark on the tooth surface.?As time goes by, this crack will gradually expand laterally in the surface.?After the crack forms a ring, the surface of the tooth will have a small area of peeling and form some shallow fatigue pits.
4.?Teeth are broken
When the root of a gear bearing load in operation engineering, like a cantilever beam, is subjected to the periodic stress of pulse which exceeds the fatigue limit of the gear material, cracks will occur at the root and gradually expand.?When the remaining part cannot bear the transmission load, the tooth breaking phenomenon will occur.Gear teeth may be broken due to serious impact, partial load and uneven material.
5, tooth surface plastic deformation
Under the impact load or heavy load, the tooth surface is easy to produce local plastic deformation, which leads to the deformation of the involute tooth profile surface.
The development of gear industry in China
China's gear industry has developed rapidly during the "Tenth Five-year Plan" : in 2005, the annual output value of gear industry increased from 24 billion yuan in 2000 to 68.3 billion yuan, with an annual compound growth rate of 23.27%, and it has become the largest industry in China's mechanical base parts.In terms of market demand and production scale, China's gear industry has surpassed Italy in the global ranking, ranking fourth in the world.
In 2006, the total industrial output value of all the gear, transmission and driving parts manufacturing enterprises in China reached 100 billion yuan, an increase of 24.15% over the same period of the previous year.The accumulative product sales revenue reached 98 billion yuan, an increase of 24.37% over the same period last year.The total accumulated profit was 560 million yuan, up from the same period last year.26.85% longer.
From January to December 2007, the total industrial output value of all gear, transmission and driving parts manufacturing enterprises in China reached 130 billion yuan, an increase of 30.96% over the same period last year.From January to October 2008, the total industrial output value of all gear, transmission and drive parts manufacturers in China reached 144.5 billion yuan, an increase of 32.92% over the same period last year.
Compared with developed countries, China's gear manufacturing industry still has some problems, such as lack of independent innovation ability, slow development of new products, disorderly market competition, weak enterprise management, low degree of information, and the comprehensive quality of employees to be improved.At the present stage, the gear industry should improve the industry concentration degree through market competition and integration, and form a group of large, medium and small enterprises with several billion yuan, 500 million yuan and 100 million yuan of assets;Through the design and development of products with independent intellectual property rights, the company has formed a batch of leading enterprises of vehicle driveline (gearbox,?drive axle assembly) to integrate the capabilities and resources of the gear industry with the supporting capabilities of leading enterprises.To achieve specialization, network supporting, forming a large number of characteristic technology, characteristic products and rapid response ability of the famous brand enterprises;Through technical reform, realize the transformation of modern gear manufacturing enterprises.
At the end of the 11th Five-Year Plan period, the annual sales of China's gear manufacturing industry could reach 130 billion yuan, with the per capita sales rising to 650,000 yuan per year, ranking second in the world in the industry.From 2006 to 2010, 100,000 units of new equipment will be added, that is, about 6 billion yuan will be invested in new equipment every year, and 20,000 units of new machine tools will be purchased, with an average unit price of 300,000 yuan per unit.By 2010, China's gear manufacturing industry should have a total of all kinds of machine tools about 400,000, including 100,000 CNC machine tools, CNC rate of 25% (higher than the average of machinery manufacturing industry 17%).
After the reform and opening up, with the rapid development of China's economic construction, in order to meet the needs of the rapid development of China's traffic and transportation, from the beginning of the 80's, China has a plan to introduce all kinds of advanced models of industrial developed countries, all kinds of foreign advanced medium and heavy duty trucks are also constantly introduced.At the same time, China's big auto factories cooperate with foreign famous auto companies to introduce foreign advanced auto production technology, including the production technology of auto gears.At the same time, China's iron and steel smelting technology level has been improved, based on ladle and secondary smelting composition adjustment and continuous casting and rolling and other advanced smelting technology, makes the steel mill to produce high purity and hardenability band narrow gear steel, so as to realize the localization of the introduction of automobile gear steel, gear steel in our country's production level on a new step.In recent years, domestic high hardenability steel containing nickel for heavy duty truck gear has been developed and applied, and good results have been obtained.Automobile gear heat treatment technology is also from the original 50-60 - s well type gas carburizing and applied to the current widely used by the computer control of continuous gas carburizing automatic line and box-type multi-purpose furnace and automatic production lines, including low pressure vacuum carburizing technology), the gear carburizing oxidation processing technology,?control gear quenching cooling technology (due to the use of special oil quenching and quenching cooling technology), gear forging stock isothermal normalizing technology, etc.The application of these technologies not only effectively controls the distortion of carburizing
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