人人文库网 > 图纸下载 > 毕业设计 > 三角带无极变速装置设计【带Solidworks三维】【7张图纸】【优秀】

外文翻译--无级变速器.doc

三角带无极变速装置设计【带Solidworks三维】【7张图纸】【优秀】

资源目录

三角带无极变速装置设计【带Solidworks三维】【7张图纸】【优秀】.rar

轴套.dwg---(点击预览)

轴.dwg---(点击预览)

计划周记进度检查表.xls---(点击预览)

装配图.dwg---(点击预览)

相关资料.doc

装配图.dwg

计划周记进度检查表.xls

轴.dwg

轴套.dwg

摘要

无级变速技术，它采用传动带和工作直径可变的主、从动轮相配合来传递动力，可以实现传动比的连续改变，从而得到传动系与发动机工况的最佳匹配。常见的无级变速器有液力机械式无级变速器和金属带式无级变速器。

自动变速器，按齿轮变速系统的控制方式，它可以分为液控液压自动变速器和电控液压自动变速器；按传动比的变化方式又可分为有级式自动变速器和无级式自动变速器。因此，无级变速器实际上是自动变速器的一种，但它比常见的自动变速器要复杂得多，技术上也更为先进。　　

　　　无级变速器与常见的液压自动变速器最大的不同是在结构上，后者是由液压控制的齿轮变速系统构成，还是有挡位的，它所能实现的是在两挡之间的无级变速，而无级变速器则是两组变速轮盘和一条传动带组成的，比传统自动变速器结构简单，体积更小。另外，它可以自由改变传动比，从而实现全程无级变速，使车速变化更为平稳，没有传统变速器换挡时那种“顿”的感觉。

关键字：无级变速器；自动变速器；齿轮变速

摘要III

AbstractIV

目录V

1 绪论1

1.1 无极变速器的发展1

1.1.1 国外无极变速器的发展及现状1

1.1.2 国内无级变速器的发展及现状2

2 纸长调节无极变速器的结构及传动原理4

2.1 纸长调节无极变速器的结构4

2.2 传动原理4

2.3 调节过程5

3 电动机的选择7

4 传动齿轮设计8

4.1 概述：8

4.2 齿轮设计8

4.2.1 选定齿轮类型、精度等级、材料及齿数8

4.2.2 初步设计9

4.2.3 几何计算9

4.2.4 强度设计11

4.2.5 齿根弯曲强度验算12

5 轴的设计计算14

5.1 概述14

5.2 轴的设计14

5.2.1 求输入轴上的功率,转速n和转矩14

5.2.2 求作用在齿轮上的力14

5.2.3 初步确定轴的最小直径14

5.2.4 按弯扭合成应力校核轴的强度15

5.2.5 精确校核轴的疲劳强度15

6 螺杆的设计计算17

6.1 根据耐磨性计算螺杆直径17

6.2 牙型、材料和许用应力18

6.3 按耐磨性设计19

6.4 验算耐磨性19

6.5 螺纹牙的强度计算20

7 轴承的校核21

7.1 概述21

7.2 轴承的校核22

7.2.1 求两轴承收到的径向载荷23

7.2.3 求轴承当量动载荷和25

7.2.4 验算轴承寿命25

8 链传动的设计计算26

8.1 概述26

8.2 链设计计算26

8.2.1 选择链轮齿数26

8.2.3 选择链条型号和节距26

8.2.4 计算链节数和中心距26

总结28

致谢29

参考文献30

1 绪论

　　　机械无级变速器是由变速传动机构、调速机构以及加压装置或输出机构三部分组成的一种传动装置。其功能特征主要是:在输入转速不变的情况下,能实现输出轴的转速在一定范围内连续变化,以满足机器或生产系统在运转过程中各种不同工况的要求。它在配合减速器传动时可进一步扩大变速范围与输出转矩,对提高产品的产量,适应产品变换需要,节、约能源,实现整个系统的机械化、自动化等各方面皆具有显著的效果。故无级变速器目前已成为一种通用的传动元件,在各工业部门已获得广泛应用。

　　　纸长调节无极变速器用于能包装多种长度的物品的包装机上。传动器的主、被动工作轮的固定和可动部分形成V形槽，与金属传送带啮合。当主、被动工作轮可动部分作轴向移动时，改变了传送带的回转半径，从而改变传动比。可动轮的轴间移动是根据包装物品的长度要求通过控制系统进行连续地调节，从而实现无极变速。

1.1 无极变速器的发展

1.1.1 国外无极变速器的发展及现状

　　　早在1490年，Leonardo da Vinic 勾画了机械无级变速器（无级变速器, Continuous Variable transmission）的草图，并简要描述了它的潜在优势。但是，机械无级变速器的真正发展是在19世纪后半叶开始的发展的，但由于当时受材质与工艺方面的条件限制,发展缓慢。直到20世纪70年代以后,一方面随着先进的冶炼和热处理技术,精密加工和数控机床以及牵引传动理论与油品的出现和发展,解决了研制和生产无级变速器的限制因素;另一方面,随着生产工艺流程实现机械化、自动化以及要求改进机械工作性能,需要大量采用无级变速器。因此这种形势下,机械无级变速器获得迅速和广泛的发展。主要研制和生产的国家有日本、德国、意大利、美国和俄国等。产品有摩擦式、链式、带式及脉动式四大类约30多种结构型式。输入功率一般为N=(0.09-30)kW,个别类型可达到N=(150-175)kW,输入转速一般为n1=(750、1500、3000)r/min;输出转速可以正、反转,增速或降速,最低转速可降低至零。自20世纪80年代以后,机械无级变速器的主要展趋向是美、日等国进行用于汽车的高速、高效、大转矩机械无级变速器的研制开发。2.2 传动原理

　　　纸长调节无级变速器用于能包装多种长度的物品的包装机上。由于包装纸的输送长度是根据被包装物决定的，因此，每当变换被包装物时，必须相应调节包装纸的输送长度。

　　　包装纸输送长度的调节是通过调节滑轮的位置，改变变速器的速比，即输纸滚筒的送纸速度来实现的。当需要改变变速器的速比时，启动电动机，经减速器降低转动速度，通过锥齿轮将电动机的动力传动到17轴上，又经链传动，降低速比，将动力传动到20轴上。通过锥齿轮将动力传至螺杆，因螺杆与滑座为螺纹配合，螺杆的转动使得滑座上下移动，从而导致滑轮上下移动。又上下对称布置的两个皮带轮是固定在轴套上的，故滑轮的移动使得主动轮的直径发生变化，从而使速比得以改变，也就改变了输送滚筒的送纸速度，使得包装纸输送长度得到了调节。

QQ截图20131129092056.gif

三角带无极变速装置设计.JPG

内容简介：: 英文原文Stepless speed technologyStepless speed technology USES belt and the work of the Lord diameters driven pulley, cooperated with the power to deliver, can realize the TRANSMISSION ratio of the continuous change, and get the TRANSMISSION and engine condition the best match between. Common step-less transmission have hydraulic mechanical step-less transmission and belt type step-less transmission , the current domestic market of the vehicles already more and more. Editor this section step-less transmission and the origin of the automatic transmissionAutomatic transmission is easy to operate, reduce fatigue driving, born of the gear drive system, the control method, it can be divided into the hydraulic controlled hydraulic and electric automatic transmission hydraulic automatic transmission; According to the change of the transmission way and can be divided into have levels of automatic transmission and no levels of automatic transmission. Therefore, step-less transmission is actually a kind of automatic transmission, but it than common automatic transmission is much more complex, more advanced technologies. Step-less transmission and common hydraulic automatic transmission of the biggest differences is on the structure, the latter is by hydraulic control gear drive system structure, still have the gears, it can be realized in between the two block is continuously variable transmission , and is two groups plate and a belt speed of than traditional automatic transmission, simple structure, smaller. In addition, it is free to change gear ratios, so as to realize the full speed stepless speed change, make more smoothly, without the traditional transmission shift at the feeling. Editor this section step-less transmission classificationTo realize stepless speed, driving mode can be adopted according to the liquid transmission, power transmission and mechanical drive three ways.Liquid transmissionLiquid transmission is divided into two kinds: one kind is hydraulic, mainly is composed by the pump and motor or the valve and pump variable speed of transmission device, apply to small and medium-sized power transmission. Another kind is hydraulic type, adopts hydraulic coupler or hydraulic torque of variable speed drive, used in high power (kw). To hundreds of thousands of The main characteristics of liquid transmission is: speed range, can absorb the impact and big to prevent transmission efficiency high, overload, long life, easy to realize automation: manufacturing precision demand is high, the price is more expensive, output characteristics for constant torque, sliding rate is bigger, running vulnerable to leak.Power transmissionPower transmission basically is divided into three categories: one kind is electromagnetic sliding type, it is in the asynchronous motor installed in electromagnetic clutch, sliding by changing its exciter current to speed, this belongs to a kind of relatively backward speed adjustment way. The characteristics of simple structure, low cost, convenient operation and maintenance, sliding, low efficiency, biggest fever, not suitable for long-term serious load operation, the general used only for small power transmission. Second is the dc motor type, changes in the magnetic flux or change the armature voltage realize the speed. Its characteristic is speed range, high precision, large and complex, high cost but equipment, maintenance difficulties, are used for medium power range (dozens to hundreds of kw), has gradually been ac motor type instead. Three kinds of ac motor type is, through the change pole, pressure control and frequency conversion for the speed. The most practical application for variable frequency speed regulation, namely deserve using a horns, and then get luffing power drive motor variable speed. Its characteristic is the speed performance is good, range, high efficiency, it can automatic control, small volume, it is suitable for a wide range of power: mechanical properties in single reducing speed constant torque, low efficiency and low speed running smooth enough, the price is higher, maintenance should be professional. In recent years, frequency converter as an advanced, excellent variable speed device rapid development of machinery, step-less transmission produced a certain impact.Mechanical transmissionThe main characteristic of the mechanical transmission is stable, rotate speed sliding rate, reliable, and has small constant power mechanical properties, the transmission efficiency is high, and simple structure, convenient maintenance, the price is relatively cheap; But parts processing and lubrication to demand higher bearing capacity, low resistance, resistance to impact overload and poor, so general suitable for medium and small power transmission.1, MTThe manual transmission (MT: Manual Transmission) gearset, because the number of teeth of each gear is fixed, each gear ratio is a fixed value (that is, the so-called level). For example, a block ratio of 3.455, the second gear is 2.056 to the five-speed 0.85, these figures are multiplied by the main reduction ratio is the total transmission ratio of the power train, 5-speed transmission 5 value (ie 5 level), so it is a step-variable transmission. The manual transmission is the most common transmission, composed of relatively AT and CVT, its structure is simple, the main axis of the input shaft, output shaft and the intermediate shaft, the shaft bearings, each gear, the synchronizer, the shift operating mechanism. Manual transmission failure rate is relatively low, the use of lower cost. 2, ATAutomatic transmission (AT: Automatic Transmission) automatic upshifts and downshifts lifting gear control, computer based primarily on speed and load (throttle pedal stroke), but also refer to a variety of signal transmission oil temperature, shift mode. The same point of the AT and MT both step-variable transmission, only that the AT has a continuous speed ratio variation in the respective gear, and the speed according to the vehicle speed automatically to achieve a gear change for hand can be eliminated block cars frustrated variable block feeling. (1) AT structure: Compared with manual wave, hydraulic automatic transmission (AT) are very different in structure and use. Manually waves mainly composed of gears and shafts, variable speed torque generated by different gear combinations; AT by the torque converter, a planetary gear and the hydraulic steering system, to achieve a variable speed hydraulic transmission and gear combination moment. Wherein the torque converter is the most characteristic parts of the AT, it is composed by the pump impeller, turbine and guide wheel member, directly enter the engine power transmitting torque and clutch effect. (2) AT advantages and disadvantages: AT without a clutch shift, gear changes less stable connection, so the operation is easy, both to car, bring comfort to the car. But the disadvantage is also one of the speed changes in response to slow, there is no manual transmission is sensitive, so many play car owners like to open a manual transmission car; Second, the economic cost of oil, the transmission efficiency is low variable torque range is limited, in recent years, the introduction of electronic control technology improve this problem; institutional complex, difficult to repair. High-Speed circulating within the torque converter hydraulic oil will generate heat, so as to use the specified high temperature hydraulic oil. In addition, if the car can not be started due to battery power shortage, you can not start with a truck or trailer bed. Hauling fault car, pay attention to the drive wheels off the ground to protect the Automatic gear from damage. (3) AMT AMT transformation, major changes in the mechanical transmission (manual transmission) based on the original manual shift control section. In the case of the overall transmission structure constant through the installation of computer-controlled robotic systems to achieve the automation of the shift. AMT is actually a robot system to complete the two movements operating the clutch and the gear selector. AMT is the production of manual wave based on the transformation, production inheritance, investment responsibility with lower production plant. AMTs core technology is computer-controlled, electronic technology and quality will directly determine the quality of the performance and operation of the AMT. 3, the CVTThe continuously variable transmission (CVT: Continuous Variable Transmission) with a step-type main difference in that: it is the speed ratio is not interrupted, but a series of discrete values, for example, has been changing from 3.455 to 0.85. CVT structure is simpler than conventional automatic transmission, smaller, neither many manual transmission gear pair, there is no automatic transmission complex planetary gear set, it depends mainly on the main driven wheel and metal band or wheel dial to achieve the speed ratio stepless change. Its principle is as several sets of gear sizes watched under the control of an aggregate with a common gearbox, and a different speed ratio, like a bicycle pedal driven by the size of the wheel and the chain wheels to rotate at different speeds. Also changes due to the different strength of the thrust generated by each group gear sizes, resulting in the transmission output speed, in order to achieve the bradycardia rotation, regardless of grade. CVT belts and variable-width ratchet power transmission, i.e., when the ratchet wheel changes the groove width of the elbow, corresponding to the shift change the contact radius of the drive wheel and the driven wheel on the driving belt, a belt ships with a rubber band, metal band and metal chain. CVT is truly stepless, it is light weight, small size, fewer parts, and AT has a high operating efficiency, lower fuel consumption. CVT disadvantage is obvious, is the transmission belt can be easily damaged, can not withstand a greater load, low power and low torque vehicles can only be restricted to about 1 liter of displacement, so the share of the automatic transmission 4. After the major car companies vigorously research in recent years, the situation has improved. CVT will be the development direction of the automatic transmission. Domestic vehicle models equipped with the CVT, such as the Nissan Teana, Sylphy, X-Trail full range of models, FAW-Volkswagen, Audi, the Guangqi Honda Fit, South Fiat Siena, Pa Baclofen, Chery Cowin.The main structure and working principle of the CVT (1) steel belt CVTThe CVT is a combination of pulleys and a steel strip, power is transmitted to replace the conventional gear device. The main components of the basic member of the including capstan group, a driven wheel set, a metal band, and a hydraulic pump, etc. Metal band by the two beams of metal rings and hundreds of sheet metal. Capstan group and a driven wheel set by the movable disc and the fixed rent, close to one side of the pulley and the cylinder can slide on the shaft, the other side is fixed. Movable plate and the fixed plate cone structure, the cone forming a V-groove to engage with the V-shaped metal transmission belt. The power output of the engine output shaft is first passed to the capstan of the CVT, and then is transmitted to the driven wheel through a V-type power transmission belt, and finally via the gear unit, the differential is transmitted to the wheels to drive the car. Through the capstan and the driven wheel when the movable disc for axial movement to change the working radius of the capstan and the tapered surface of the driven pulley with a V-type drive belt engaging, thereby changing the transmission ratio. The amount of axial movement of the movable platen is needed by the driver through the control system to adjust the capstan, the follower wheel cylinder of the hydraulic pump pressure to achieve. Continuously adjusted in order to achieve a continuously variable transmission can be achieved due to the working radius of drive pulley and driven pulley. In the the CVT hydraulic system, the role of the slave cylinder to control the tension of the metal band, in order to ensure the efficient and reliable delivery of power from the engine. Active cylinder to control the position of the driving bevel wheel moves axially along the V-groove move in the the capstan group metal band, due to the constant length of the metal strip, a group of the driven wheel in the opposite direction on the metal strip along the V-groove changes. Change the radius of gyration of the metal strip in the the capstan group and a driven wheel set on the continuous variation of the speed ratio. When the car is started, the small working radius of the driving wheel, the transmission can get a larger gear ratio, thus ensuring the drive axle to have enough torque to ensure the car has a higher acceleration. As the speed increases, the capstan working radius is gradually reduced, the working radius of the driven wheel increases accordingly, and the CVT transmission is decreased so that the car can travel at higher speeds.(2) wheel rotary CVTCan be used to deliver more power and torque applicable in a larger displacement automobiles. This CVT combination of turntable and roller transfer drive torque and change the transmission ratio. It is changed by moving the power roller transmission ratio, input dial to the power roller force is applied in a timely manner, so that CVT gear ratio change of the reaction faster than the strip-type CVT, in order to achieve the drivers accelerator input of the transmission ratio changes linearly. In addition, similar to the strip-drive CVT, the continuous change of the transmission ratio so that the driver can enjoy seamless smooth shifting, without any shift shock.Engine power transmitted to an input dial input dial to the rotational movement of the transmitting power to the wheel, and then passed through the rollers to the output of the turntable. By continuously changing the inclination angle of the power roller, CVT performs a smooth and continuous gear ratio changes. The size of the contact circle between the points of contact between the input wheel and the power roller circle size and the output of the dial and the power roller is changed according to the change of the inclination angle of the power roller. The size ratio of the circle corresponding to the input the turntable and output rotational speed ratio of the turntable, the rotational speed ratio is equal to the drive ratio. When the the output dial circle is larger, the rotation of the output dial slower than the input dial, which is equivalent to the traditional low-end of the transmission. Conversely, output dial circle small, the rotation of the output dial faster than the input dial, which is equivalent to the high-end of the traditional transmission.The momentum wheel is supported on the trunnion connected above and below the assembly and the hydraulic servo piston can move up and down.Power roller, this configuration allows each roller rotating around the trunnion.When the power roller axis through the wheel center, does not produce the force of the tilt of the wheel. Accordingly, since the wheel tilt remains unchanged, it is no change in the transmission ratio.Since the high-speed rotation of the turntable, as long as the wheel moves up or down. 0.1mm to 1.0mm, can be tilted. This immediate response to a gear ratio change instruction, the EXTROID CVT cause particularly rapid transmission ratio change.The inclination angle of the power roller hydraulic mechanism for manipulation. Despite the transmission ratio is changed by tilting the power roller, but not directly to the wheel afterburner. Instead, the force generated using the turntable so that the inclined roller when the vertical movement of the wheel from the center axis, the turntable on the roller tilt. As the high-speed rotary dial, dial the forces generated by the wheel movement and force the hours immediately tilt, so we can quickly feel the transmission ratio changes significantly. When the drivers accelerator input, and the linear acceleration and deceleration.中文译文无级变速器无级变速技术，它采用传动带和工作直径可变的主、从动轮相配合来传递动力，可以实现传动比的连续改变，从而得到传动系与发动机工况的最佳匹配。常见的无级变速器有液力机械式无级变速器和金属带式无级变速器自动变速器，按齿轮变速系统的控制方式，它可以分为液控液压自动变速器和电控液压自动变速器；按传动比的变化方式又可分为有级式自动变速器和无级式自动变速器。因此，无级变速器实际上是自动变速器的一种，但它比常见的自动变速器要复杂得多，技术上也更为先进。无级变速器与常见的液压自动变速器最大的不同是在结构上，后者是由液压控制的齿轮变速系统构成，还是有挡位的，它所能实现的是在两挡之间的无级变速，而无级变速器则是两组变速轮盘和一条传动带组成的，比传统自动变速器结构简单，体积更小。另外，它可以自由改变传动比，从而实现全程无级变速，使车速变化更为平稳，没有传统变速器换挡时那种“顿”的感觉。为实现无级变速，按传动方式可采用液体传动、电力传动和机械传动三种方式。液体传动液体传动分为两类：一类是液压式，主要是由泵和马达组成或者由阀和泵组成的变速传动装置，适用于中小功率传动。另一类为液力式，采用液力耦合器或液力矩进行变速传动，适用于大功率（几百至几千千瓦）。液体传动的主要特点是：调速范围大，可吸收冲击和防止过载，传动效率较高，寿命长，易于实现自动化：制造精度要求高，价格较贵，输出特性为恒转矩，滑动率较大，运转时容易发生漏油。电力传动电力传动基本上分为三类：一类是电磁滑动式，它是在异步电动机中安装一电磁滑差离合器，通过改变其励磁电流来调速，这属于一种较为落后的调速方式。其特点结构简单，成本低，操作维护方便：滑动最大，效率低，发热严重，不适合长期负载运转，故一般只用于小功率传动。二类是直流电动机式，通过改变磁通或改变电枢电压实现调速。其特点是调速范围大，精度也较高，但设备复杂，成本高，维护困难，一般用于中等功率范围（几十至几百千瓦），现已逐步被交流电动机式替代。三类是交流电动机式，通过变极、调压和变频进行调速。实际应用最多者为变频调速，即采用一变幅器获得变幅电源，然后驱动电动机变速。其特点是调速性能好、范围大、效率较高，可自动控制，体积小，适用功率范围宽：机械特性在降速段位恒转矩，低速时效率低且运转不够平稳，价格较高，维修需专业人员。近年来，变频器作为一种先进、优良的变速装置迅速发展，对机械无级变速器产生了一定的冲击。机械传动机械传动的特点主要是：转速稳定，滑动率小，工作可靠，具有恒功率机械特性，传动效率较高，而且结构简单，维修方便，价格相对便宜；但零部件加工及润滑要求较高，承载能力较低，抗过载及耐冲击性较差，故一般适合于中、小功率传动。1、MT手动变速器（MT：Manual Transmission）采用齿轮组，由于每挡齿轮组的齿数是固定的，所以各挡速比是个固定值（也就是所谓的“级”）。比如，一挡速比是3.455，二挡是2.056，再到五挡的0.85，这些数字再乘上主减速比就是汽车动力传动系统的总传动比，5挡变速器共有5个值（即有5级），所以说它是有级变速器。手动变速器是最常见的变速器，相对AT和CVT而言，它的结构最简单，主要由输入轴、轴出轴和中间轴、各轴轴承、各挡齿轮、同步器、换挡操纵机构组成。手动变速器故障率相对较低，使用成本也较低。 2、AT自动变速器（AT:Automatic Transmission）可以自动升挡和降挡，电脑主要根据车速和负荷（油门踏板的行程）进行升降挡控制，同时还要参考变速器油温、换挡模式等多种信号。AT与MT的相同点就是二者都是有级式变速器，只不过AT在各个挡位都有一段连续的速比变化，而且能根据车速的快慢来自动实现挡位的增减，可以消除手挡车“顿挫”的变挡感觉。（1）AT的结构：与手动波相比，液力自动波（AT）在结构和使用上有很大的不同。手动波主要由齿轮和轴组成，通过不同的齿轮组合产生变速变矩；而AT是由液力变扭器、行星齿轮和液压操纵系统组成，通过液力传递和齿轮组合的方式来达到变速变矩。其中液力变扭器是AT最具特点的部件，它由泵轮、涡轮和导轮等构件组成，直接输入发动机动力传递扭矩和离合作用。（2）AT的优缺点：AT不用离合器换档，档位少变化大，连接平稳，因此操作容易，既给开车人带来方便，也给坐车人带来舒适。但缺点也多，一是对速度变化反应较慢，没有手动波灵敏，因此许多玩车人士喜欢开手动波车；二是费油不经济，传动效率低变矩范围有限，近年引入电子控制技术改善了这方面的问题；三是机构复杂，修理困难。在液力变扭器内高速循环流动的液压油会产生高温，所以要用指定的耐高温液压油。另外，如果汽车因蓄电池缺电不能启动，不能用推车或拖车的方法启动。如果拖运故障车，要注意使驱动轮脱离地面，以保护自动波齿轮不受损害。（3）AMTAMT在机械变速器（手动波）原有基础上进行改造，主要改变手动换档操纵部分。即在总体传动结构不变的情况下通过加

温馨提示:
1: 本站所有资源如无特殊说明，都需要本地电脑安装OFFICE2007和PDF阅读器。图纸软件为CAD,CAXA,PROE,UG,SolidWorks等.压缩文件请下载最新的WinRAR软件解压。
2: 本站的文档不包含任何第三方提供的附件图纸等，如果需要附件，请联系上传者。文件的所有权益归上传用户所有。
3.本站RAR压缩包中若带图纸，网页内容里面会有图纸预览，若没有图纸预览就没有图纸。
4. 未经权益所有人同意不得将文件中的内容挪作商业或盈利用途。
5. 人人文库网仅提供信息存储空间，仅对用户上传内容的表现方式做保护处理，对用户上传分享的文档内容本身不做任何修改或编辑，并不能对任何下载内容负责。
6. 下载文件中如有侵权或不适当内容，请与我们联系，我们立即纠正。
7. 本站不保证下载资源的准确性、安全性和完整性, 同时也不承担用户因使用这些下载资源对自己和他人造成任何形式的伤害或损失。

人人文库网所有资源均是用户自行上传分享，仅供网友学习交流，未经上传用户书面授权，请勿作他用。