双偏心曲柄轴及夹具设计制造(优秀含CAD图纸+设计说明书)
双偏心曲柄轴及夹具设计制造(优秀含CAD图纸+设计说明书),偏心,曲柄,夹具,设计,制造,优秀,优良,cad,图纸,说明书,仿单
双偏心曲柄轴及夹具设计制造,研究的背景及意义,背景:在机械加工飞速发展的今天,轴类零件发挥的作用不可替代,但是普通的轴类只能带动工件自传,在提倡高效率的今天,既可以传递自传,又能传递公转的偏心轴类零件便被提了出来,我所研究的课题便是其中之一。 意义:双偏心曲柄轴是减速器产品中重要的零部件之一,该零件要求尺寸,精度各方面都较为严格,加工难度较大,攻克这个难题,会对该轴乃至减速器的大量生产带来很大影响,因此意义非凡。,研究内容与方法,内容:双偏心曲柄轴的加工及其夹具设计制造, 主要围着此零件的机械加工工艺规程展开,包括定位基准、工艺路线、工艺装备、加工余量、工序尺寸等等,最后针对比较难加工的双偏心部分外圆,设计出专用夹具。 方法:首先用一个已经加工好的零件作为设计夹具的零件,测量后用CAD将其转化成为图纸,看图纸了解零件的特点,针对其特点制定加工工艺。其次了解夹具相关知识,用所学的知识设计夹具,并用CAD软件绘出夹具的零件图以及装配图。最后用所设计夹具进行零件加工并得出误差分析统计报告。,论文的结构,1绪论 2一般偏心轴的加工的简介 3双偏心曲柄轴的机械加工工艺规程 4专用夹具的设计 5双偏心曲柄轴加工误差的统计分析 6结论,论文的主要内容,1 首先分析零件的结构特点,论文的主要内容,2 通过对零件的分析,制定工艺规程,包括毛坯的选择,工艺装备的选择,以及通过对两种工序的比较,得出较优选择。然后计算加工余量、工序尺寸等参数。 工序1:检查毛坯有无问题。 工序2:车右端面,打中心孔。粗车一端30外圆,粗车双偏心圆上下侧母线距离43.4外圆。 工序3:倒个加工,保证长度情况下车另一端面打中心孔。粗车另一端30的外圆。车俩30外圆轴底尺寸为2.51的槽、1.5x1的槽、车俩偏心圆中间直径为32.6的槽。 工序4:调制热处理。 工序5:半精车30外圆(两端),双偏心圆部分外圆,倒角。 工序6:滚齿机滚花键。 工序7:用做双偏心曲柄轴的车床专用夹具,利用花键配合粗车,半精车俩39双偏心圆。 工序8:碳氮共渗热处理。 工序9:将工件以两顶尖法定位,粗磨、精磨俩30外圆,在磨床将花键磨至尺寸。 工序10:用设计出的加工此工件的磨床专用夹具,一头以花键定位,一头以顶尖定位,精磨39双偏心圆至要求尺寸。 工序11:修正工件,去锐边、毛刺。 工序12:终检,入库。,论文的主要内容,3 夹具的设计 最难加工的部分就是偏心圆的部分,通过定位方案的选择,切削力与夹紧力的计算后,针对其双偏心圆的特点我设计出的夹具如下:,论文的主要内容,夹具 夹具体,论文的主要内容,论文的主要内容,4 用设计出的夹具加工50个工件并对其进行了误差分析,通过对偏心距的测量,得下表:,论文的主要内容,进行分组计算,画出的图符合正交分布,如右图:,然后绘制X-R图知工艺稳定(下图),最后计算得产品的不合格率为2.28%,知夹具符合要求。,大学本科的学习生活即将结束。在此,我要感谢所有曾经教导过我的老师和关心过我的同学,他们在我成长过程中给予了我很大的帮助。本文能够顺利完成,要特别感谢我的导师孙建军老师,感谢各位系的老师的关心和帮助。 最后向所有关心和帮助过我的人表示真心的感谢。,致谢,Eccentric shaft heat treatment and mechanical properties research Abstract This paper focuses on the eccentric shaft material 20Cr heat treatment (carburizing, quenching, a tempering, and second tempering) process and its main mechanical properties, high hardness is main properties. Analysis how Carburizing temperature ,time an, cooling method ,direct quenching ,a quenching, secondary quenching and other factors defect on the mechanical properties and organization from the theory. After confirmed 20Crs eccentric shafts best heat treatment process parameters and the best carburizing quench way (salt bath, direct quenching, low temperature tempering), analysis and detect the infiltration depth of the carburized, microstructure and mechanical parts.Key words: eccentric shaft, heat treatment, carburizing, carburizing temperature, cooling method, carburized layer ChapterThe introduction1.1 Preface The role of the eccentric shaft is to adjust the center distance between convenient, eccentric shaft is usually used in the V-belt drive in the planar linkage. Normal shaft can only drive the work piece, but the eccentric shaft, not only can pass the rotation, also can pass the revolution. Now the U.S. compressor giant Copeland is using eccentric shaft to drive the vortex of revolution and efficient compression formulations fast. Eccentric shaft is an important transmission part of electric tool electricity hammer. Install the eccentric shaft and let it running to dead spots position will not produce locks by inertia effect. The most common example is: household sewing machine feet moving wheel of the operation. Rotating eccentric shaft driven machine is the indispensable machinery parts.Schematic diagram of the eccentric shaft1.2 The purpose of the eccentric shaft and performance requirements Eccentric shaft is widely used in mining, electromechanical, water conservancy, etc. With the increase in the production of these products, and consumer groups asked the continuous improvement of the quality of the eccentric shaft is imminent, exported 400 million air-conditioning compressor units by 2008, air exports increased by 27% than in 2005. Air conditioning compressor is exported to South East Asia mainly. Because the eccentric shaft under enormous impact load at work, and the hammer of the working conditions, many dust, parts wear easily. Therefore, the surface of the eccentric shaft required high hardness, wear resistance and fatigue strength, while the core part has a certain strength and good plasticity, toughness and other special properties.1.3 The situation at home and abroad 1.3.1 Domestic Research Trends Heat treatment has a long history in China, with other scientific and technological development, heat treatment technology develop the rapidly . (1) Namely, the continuous improvement of experimental methods and techniques. Understanding the relationship between the changes in the organization of metal rules and microstructure, develop new heat treatment process. (2) In the basic theoretical aspects continuously make achievements. (3) The research of surface chemistry, develop all kinds of surface protective heat treatment and surface strengthening heat treatment. (4) Other new energy, new technology development, make heat treatment process become complex process. Recent sessions of the International Conference on Materials and Heat Treatment predicts the development of ancient and modern metal heat treatment process and heating equipment t, the basic view is: (1) heating equipment In the heating device to more development of electric furnace, especially the development of induction furnace, reducing fuel furnace. Most of the furnace and heat treatment equipment to achieve automation and digital control, not only can reduce the labor force, but the premise is to improve the quality of heat treatment. (2) Heat treatment process a. Improved conventional heating process. Air heating will be vacuum heated, controlled atmosphere or protective atmosphere heating, as well as vacuum and controlled atmosphere heating joint will replace air heating. With the vacuum technology progress, vacuum heat treatment towards furnace temperature increased and the automation. Induction heating treatment, tend to increasing power and frequency range direction. b. expansion of the surface heat treatment and various types of chemical treatment instead of the whole heat treatment. 1.3.2 Heat treatment equipment and heat treatment technology abroad status () in the early 1970s, American Society for Metals (ASM), British Wolf Morrison heat treatment center (Wolfson Heat Treatment Center) and the former Yugoslavia (now Croatia) have established the material and Heat Treatment, did it may, according to the database of mechanical performance requirements after heat-treatment of computer-aided material selection, or known material and Heat Treatment process foresee the organization and performance last. Then Europe, Japan and other advanced industrial countries to develop computer auto-calculating on all kinds of heat treatment process control technology, began the process parameters under computer control, and analog control technology in production gained in application. The international well-known anufacturers of many successive and cycle type heat treatment line adopted by programmable Controller (Programable) or microprocessor Controller of single control or group control. Foreign heat treatment factory attaches great importance to the cooling heating process. According to the product technology and process requirement, can undertake rapid cooling, oil quenching cooling, disposable gas quenching cooling, etc. By gas quenching way before the quenching cooling nitrogen and helium gas, and now the use of air jet, the strong in fast speed, quenching cooling after only extremely thin surface oxidation, are pale, parts, and still beautiful color saved a great deal of nitrogen and inert gas, so that treatment costs will decline further. Vacuum low-pressure carburizing combined with high-pressure gas quenching is an advanced carburizing today, it has carburizing speed, excellent carbide organization ,quenching cracking and little deformation, saving energy and carburizing agent raw materials, carburized parts surface quality is good, be helpful for environmental protection etc. () heat treatment equipment: The trend of foreign heat treatment furnace development: (1) stove based on the power is increasing, oil for heat treatment furnace ratio decreasing. (2) To product surface quality request more strictly controlled atmosphere heat treatment furnace, this occupies an important position still. (3) Lining tends to use of lightweight materials, the application in resistance furnace with heat-resistant component and nonmetallic furnace the proportion of heating elements increase gradually. (4) The microcomputer and PLC accelerates the development of heat, and have with the other automation line of automatic heat treatment process of trend.1.4 eccentric shaft failure forms and preventing measures Shaft loading: fatigue, impact, tensile, compression, bending, twisting, cutting, wear, surface changes, size changes, etching, corrosion and other failure modes. (1) eccentric shaft under heavy load at work, subject to bending stress, wear and tear in the neck, by the main have occurred wear fracture and axial crack two circumstances parts (2) axial crack, axial crack is eccentric shaft parts common failure form, this crack except material adverse outside, main is caused by excessive heat surface tension stress caused by its quench-hardening ability, due to merger part weeks than axial tensile stress surface , and material surface tensile stress of lateral performance under longitudinal, prevent such hardening layer, and promptly tempering. (3) Axis failure form: There are insufficient due to fatigue resulting fatigue fracture, static strength due to lack of plastic deformation or brittle fracture, wear, and exceed the allowable range of deformation and vibration. (4) axial fracture is mainly reverse fatigue fracture.Chapter II Theoretical analysis2.1 Heat Treatment of eccentric shaftUnified Digital Code: A20202【Chemical Composition】 (mass fraction) (%)C: 0.180.24Si: 0.170.37M n: 0.500.80Cr: 0.701.00【Mechanical properties 】Sample blank size (mm): 15 Heat buried: The first quenching temperature: 880 ; Coolant: water, oil The second quenching temperature: 780 820 ; Coolant: water, oil Tempering heating temperature: 200 ; Coolant: water, air Tensile strength 835MPa Yield point: 540MPaLaSalle epigastria long rate: 10% Section shrinkage: 40% Shock absorption 47J impact energy Brinell hardness (annealed or high temperature tempering state): 179 【Main Special items】 Compared with the 15Cr steel , it has higher strength and its quench-hardening ability in oil critical quenching, up to 4 22mm diameter appearing in water to critical quenching of 11 diameter 40mm lottery, but the firmware is poor, when the steel carburizing Grains are still growing tendency, when the direct quenching temperature on impact toughness of greater impact, so the secondary quenching after carburizing need to improve the toughness of the Ministry of parts heart, no temper brittleness; steel, plastic strain of cold high in the cold state The following drawing; machinability high temperature in the state of normalizing or quenching and good, but after annealing poor; welding is good, generally do not need heat treatment after welding, but the thickness of the parts is greater than 15mm to be preheated before welding to the 100 to 150 .【examples Of Application】 This kind of steel is used mostly manufacturing heart the demand is higher, intensity of surface bear wear, section 30mm below in complex shape and load or small carburized parts (oil quenching machine), such as: transmission gear, gear axle, CAM, worm, etc. For small and high heat treatment deformation wear parts, carburizing should high-frequency surface after quenching, such as modulus is less than 3 gear wheel, bearing etc. 20Cr can also be used in conditioning condition, used to make the speed of work and under moderate impact load large parts, this steel also can be used as low carbon steel, martensitic quenching further increased the yield strength and steel tensile strength.Chapter experimental materials and experimental methods3.1Materials: Material for this study is the eccentric shaft 20Cr, 20Cr is the carbon content of 0.2% for the carburization of low carbon steel, 20Cr steel than carbon steel carbon content of the same strength and hardenability were clearly high, oil quenching to the semi-martensitic hardenability of hardness for the 20 23mm. Compared with the 15Cr steel has high strength and hardenability, the critical quenching diameter, oil is about 4-22mm, the water is about 11-40mm, poor toughness, good welding, after welding - as not need heat treatment. Uses: Most of hardened steel used for the manufacture of the Ministry of the heart require a higher strength, to withstand the friction surface, cross-sectional size or shape of the 30mm less complex and less load carburized parts (oil quenching), such as machine transmission gear, gear shaft, cam, worm, etc., on the requirements of small and high heat deformation resistance of the parts after carburizing and high frequency surface hardening, such as modulus 3mm of gears, shafts and spline shaft. It can also be used in the quenched state, for the manufacture of medium-velocity impact load larger and bear parts. This steel quenching temperature after tempering has good comprehensive mechanical performance, low-temperature impact toughness, and good temper brittleness not obvious. Swigging carburizing of grain has grown, so the requirements second tend to enhance the core quenched ductile, unfavorable cooling quenching. When is the fire HB170 217 hardness for when about 65 percent relative cutting machining, walkability medium, should be preheated before welding to 100 150 , cold deformation plasticity medium.3.2 Experiment:The heat treatment process in this experiment were as follows:3.2.1 installed furnace: the axis (cleaning) vertically into the basket mesh, large hole down, plug hole facing up gambling sales, in the installed furnace, put a pattern into the end of the eccentric shaft basket. Will be installed for the work piece material into the furnace basket hanging clothes time to close the lid, tighten the lid bolts, drops of methanol, the fans, transmission temperature, into the exhaust period. Open the vent whole pattern.3.2.2 Exhaust: 880 installed outside the pattern 2, the amount of methanol drops of 180-200 drops / min; 880-920 stop drops of methanol, the drops of kerosene, kerosene drop volume 180-200 drops / min; 910 920 , 30 minutes, the amount of kerosene drops of 180-200 drops / min; Close 30 minutes after the temperature pattern holes, Exhaust flame length of 80 150mm, into the carburizing period.3.2.3 carburization of 910 920 , 180 points, the amount of kerosene drops of 180-200 drops / min; water column 30 60mm.3.2.4 Diffusion Cooling: 0.6mm deep diffusion layer, it can spread into the cool, adjust the volume of kerosene drops of 100 to140 drops / min, 10 to 30mm water column.3.2.5 released air.3.4. Metallographic specimen preparation, according to the microstructure and hardness gradient measurements3.4.1 The preparation phase include microscopic pattern sampling, grinding, polishing, etching and other processes.Sampling pattern should be selected according to purpose of the study, whichever is representative of the site.Grinding Cut in the grinding machine polished style, pointed to rounding. Then 180 , 240 , 300 and 600 grit polishing cloth, and back with 800 , 1500 progressively metallographic sandpaper grinding, grinding to 2000 has been rough sandpaper before polishing and fine polishing .Grinding style, each for a grinding step (i.e. for-One sandpaper), the style should be turned 90 degrees the direction of grinding. It will show the wear scar is rubbed off. No abrasive cloth in each style (paper) on the grinding, the mill should be in one direction and avoid grinding back and forth, but to impose the appropriate force of style.Polishing The pattern needs to be polished finely ground. The purpose of polishing is to remove the legacy of fine grinding fine when worn to obtain bright mirror. Style is polished on the polishing machine specific, and speed like 100 150r/min. Polishing disk polishing spread when there are velvet and other fabrics, and continue to drip slurry. Polishing or Mg0 by Cr203 abrasive and a very fine-grained water suspension formed, relying on the polishing slurry in the fine grinding powder and style that arise between the role of relative grinding and rolling to eliminate the wear scar.Polishing grinding style should be uniform so that pressure in the rotating polishing disc and the edge to the center along the disk constantly for radial reciprocating motion.Erosion The pattern has been polished before etching must be observed under the microscope. Erosion is mainly dependent on the metal etchant solution or electrochemical corrosion process, the surface of the metal pattern and the composition of grain and grain boundary phases present between the slightly uneven, under the microscope can be clearly observed on the style surface, etching time should be appropriate, the general pattern can be grinding halt when dark. If lack of repeated erosion. After etching rinse immediately with water, then rinse with alcohol and finally dried with a hair dryer, pattern can be placed on the optical microscope observation. 3.4.2 Organization and using optical microscope according to microstructure.3.4.3 Determination of the hardness gradientMicro Hardness Tester朗读显示对应的拉丁字符的拼音字典In recent years, micro hardness measuring the hardness of commonly used equipment. Hardness is measured by reading down micro hardness. The focusing mechanism, measuring microscope, loading bodies, correct choice of load, speed automatic loading Unloading Test force control of test force and the proper time, the optical amplification by micro hardness, measured in a certain test .Force of diamond pyramid indenter pressed into the measured object left after the diagonal length of indentation, to find the hard object under test Degree of value. Chapter IV Experimental results and analysis4.1 The hardness of the experimenttemperatureSurfaceFilter layerHeart MinistryRoom temperature5963HRC3642HRC2732HRCSurface hardness HRC62.3, the minimum hardness of heart HRC27.2 the Ministry of the eccentric shaft has reached the performance requirements, and the Ministry of hardness from the surface to the heart decreases in line with the surface of high hardness, high wear resistance of the heart has good strength and toughness of the Department of requirements. The following figure is the hardness, the distance between the Ministry of centrifugation: Figure on the display and hard cover table further away, like centrifugal and hardness of the Ministry of the larger maximum hardness of the surface to meet the performance requirements of the eccentric shaft. Spacing is 0.25mm朗读显示对应的拉丁字符的拼音字典朗读显示对应的拉丁字符的拼音字典朗读显示对应的拉丁字符的拼音字典tttTTTKkk 朗读显示对应的拉丁字符的拼音4.2 Metallographic analysis and discussion Through the above process and experimental results, we can get the 20Cr eccentric axis of the heart obtained after carburizing Department of 27HRC-32HRC hardness and surface hardness 59 63HRC, which can guarantee the eccentric shaft has good wear-resistant surface Resistance, high strength and center better plasticity and toughness, while maintaining a core part of the impact resistance of high capacity, it reached the surface carburization purposes.We know that the surface carburization treatment is to carbon content of 0.1% -0.25% of the steel on the carbon potential of the medium to high, by having high activity of carbon atoms diffuse into the steel within a certain thickness of the carbon content is higher The carburized layer, and then quenched tempering, the surface of the work piece by high carbon content layer M, and the Ministry for the heart to maintain the original concentration of carbon content in the carbon content of low M, M hardness mainly related to its carbon content, Therefore, treatment and follow-up treatment by carburizing the work piece can be tough in the performance of external hardware.Surface structure (high-carbon tempered marten site + residual austenite + carbide)朗读显示对应的拉丁字符的拼音字典Filter layer (marten site + retained austenite)Ministry of the heart (low-carbon tempered marten site)Obtained by the above microstructure picture we can see on the eccentric shaft to the surface after carburizing treatment are high-carbon marten site or acicular marten site, the needle is usually in the high-carbon marten site steel and iron-nickel alloy to form - the typical marten site. For low carbon steel, carbon content in less than 1.0%, and the coexistence of marten site, the carbon content of only 1.0% higher than when alone. It is a two-dimensional shape of convex lens sheet, compared with the sample surface into a needle or bamboo-shaped cross section, it is also known as plate marten site or lens plate marten site. Lens sheet sub-structure is mainly twins, it is also known as twin marten site.
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