资源目录
压缩包内文档预览：
编号：120945298
类型：共享资源
大小：1.98MB
格式：ZIP
上传时间：2021-04-11
上传人：221589****qq.com
认证信息
个人认证
李**（实名认证）
湖南
IP属地：湖南
40
积分
- 关 键 词：
-
Y38
滚齿机
进给
系统
设计
说明书
CAD
- 资源描述：
-
Y38滚齿机进给系统设计【说明书+CAD】,Y38,滚齿机,进给,系统,设计,说明书,CAD
- 内容简介：
-
齿轮的制造方法刨削 齿轮齿间的空间形状是复杂的，而且随着齿轮的齿数和模数的不同而变化，因此大多数的齿轮制造方法采用展成齿廓而不是成形加工。刨削采用往复运动的齿条刀，当齿条刀实际上绕齿轮怌料滚切并且沿其螺旋线方向运动时，齿形就会被逐渐展成。与普通的刨削加工相同，在回程中齿条刀与齿轮脱离接触。这种加工方法的最大好处是，刀具为具有直线齿形或接近于直线齿形的齿条，其齿面易于进行精加工。由于刀具和滑枕的质量较大，造成加工速度缓慢，因此这种方法几乎不在大批量的生产中应用。对于单件或者少量的齿轮加工而言，缓慢的形成速度带来的影响不大，而且较低的刀具成本对于那些特殊规格和需要进行齿廓修形的齿轮来说则是一个有利条件。插削 插削加工在本质上与刨削加工类似，只是采用圆形刀具来取代齿条刀。其结果是减少了往复运动惯性，在加工过程中可以采用比刨削高得多的行程速度。现代插齿机在加工汽车齿轮时可以达到每分钟2000次切削行程。插齿刀的形状与渐开线齿轮大致相同，但是其齿顶是圆的。由于刀具与工件之间的展成传动只包含圆周运动，因此不需要齿条或者丝杠。在刀具的每一次行程中，通常刀具和工件的切向移动距为0.5mm。在回程中，刀具必须退让1mm以留出间隙。否则，在退刀时，刀具会擦伤已加工表面，并且加快刀具的磨损。 插齿加工的有点是生产效率高和可以将齿插刀接近轴肩处。令人遗憾的是加工斜齿轮时，需要有一个能够产生绕插齿运动行程行程本身旋转的螺旋导轨。这种螺旋导轨不容易制造，或者说其制造成本太高。由于对每种不同螺旋角的齿轮，应该制造不同参数的插齿刀和螺旋导轨，因此这种方法仅适用于斜齿轮的大批量加工。插削加工的一大优点是能够加工诸如行星齿轮传动所需要的内齿轮。滚削 滚齿是最常见的金属切削方法。它采用齿条展成原理，但是通过安装在旋转刀具上的许多齿条来避免缓慢的往复运动。这些齿条轴向排布，形成有缝的蜗杆。由于滚刀和工件均不做往复运动，因此滚齿加工时金属切削率很高。对于普通滚刀可以采用40r/mm的切削速度，对于硬质合金滚刀可以采用高达150m/min的切削速度。一般采用直径为100mm的滚刀，其旋转速度为100r/min，一个20个齿的齿轮将以5r/min的速度旋转。工件的每一转将有0.75的进给量，因此滚刀每分钟要对工件大约进给4mm，在汽车制造中，采用多头粗加工滚刀，达到每转3mm的打进给量。这样，当刀具的转速为100r/min时，采用双头滚刀加工齿数为20的齿轮，其进给量可以达到30mm/min。拉削 通常不采用啦学的方式加工鞋齿轮，但是在直齿轮加工中拉削是适用的。在这种情况下，拉削主要被用来加工其他任何一种方法都不容易加工的内花键。与所有的拉削加工一样，因为设备的费用很高，齿轮拉削方法只有在大批量生产时才是经济的。通过拉削可以获得高精度和低表面粗糙度。如同所有的切削加工一样，拉削也是只能用来加工软材料。随后应该的该材料进行表面硬化或者热处理，而这会产生变形。剃齿 采用剃齿方式对可以处于软状态的齿轮进行精加工。其目的是通过采用具有提高齿形精度能力的刀具与经过粗加工的齿轮进行啮合来降低齿面粗糙度和改善齿廓形状。剃齿刀像一个齿轮，在其根部有一附加的空隙（用于排除切削和冷却液），在齿廓上开许多小曹以形成切削刃。剃齿刀与经过粗加工的齿轮成交错轴啮合传动。这样在理论上沿着轮齿有一个具有相对速度的点接触，从而产生刮削作用。剃齿刀的到齿具有相当的弯曲柔性，因此只有当它们在两个齿轮之间并且与这两个齿轮都接触时，才能有效地进行切削工作。在齿轮和刀具高速旋转的同时沿齿面横向进给，大约可以切除100um的材料，切削周期可能少于半分钟，机床的价格也不昂贵，但是刀具比较精密，难于制造。磨削 磨削是非常重要的，因为它是加工淬硬齿轮的主要方法。当对热处理变形的预先校正达不到齿轮所要求的高精度时，就必须采用磨削加工。最简单的磨齿方法是成形磨削法。采用由精密切削成形的样板控制的单刃金刚石可将砂轮修整成精密的形状。成形砂轮沿着齿轮轴向往返进给。在一个齿轮的形状加工完成以后，通常除去100um的金属。然后，齿轮将会被分度到下一个齿轮空间。这种方法的加工速度相当慢，但是在整个加工过程中都可以获得较高的精度。对于不同的模数，齿数，螺旋角或者齿廓修行量，需要采用不同的的砂轮修整样板，因此就需要有较长的安装调整时间。最快的磨削方法采用与滚齿相同的原理，但是适应截面为齿条的砂轮来取代有排屑槽的蜗杆形滚齿刀。砂轮只能被切削成单头蜗杆形，由于齿轮的转速通常高达100r/min，因此设计具有所需要的精度和刚度的驱动系统都是困难的。尽管在磨削过程中砂轮和工件有产生不同的变形量的可能，可能需要用砂轮的形状补偿机床变形的影响，磨削加工的精度还是比较高的。将砂轮展成一个蜗杆形状是一个缓慢的过程，这是因为修整砂轮的金刚石不仅要行程齿条外形，而且需要在砂轮的旋转是进行轴向移动。一旦砂轮整形完毕以后，就能快速地磨削齿轮，直至需要重新修整时为止。这是一个最常用的，高效率地加工小齿轮的方法。机械设计准则设计是从实际或者假象的需要开始的。对于现有的设备可能需要在耐用性，效率，重量，速度或成本等方面做进一些改进工作；也可能需要新的设备完成以前由人来做的工作，例如计算或者装配。当目标完成获部分被确定以后，下一个设计步骤是对能够完成所需要功能的机构及其布局进行总体设计。对于此项工作，徒手画的草图是很有价值的，它不仅可以记录下我们的想法，而且还有助于与别人讨论，特别是和自己的大脑进行交流，从而促进创新想法的生产。当一些零件的大致形状和机构尺寸被确定后，就可以开始认真的分析工作。分析工作的目的是要在重量最轻，成本最低的情况下，获得令人满意，即优良的工作性能，并且还要安全耐用。对于每个关机承载截面，应该寻求最佳的比例和尺寸，同时要对这几个零件的受力进行平衡。要对材料和处理方式进行选择。只有根据力学原理进行分析才能达到这些重要目的。这些分析包括根据静力学分析反作用和充分利用摩擦力，根据动力学原理分析惯性，加速度和能量；根据弹性力学和材料力学分析应力和变形；根据流体力学来分析润滑和流体传动。最后，完成基于功能要求和可靠性进行的设计，且要制作一台样机。如果实验结果令人满意，而且该装置将要进行批量生产，就应该第最初提出的设计方案做一些修改，使其能以较低的生产成本进行生产。在以后的制造和使用期间内，如果生产了新的想法或者根据试验和经验所做的进一步分析结果表明，可以有更好的替代方案，则很可能对原设计方案进行修改。销售吸引力，客户的满意程度和制造成本均与设计有关，而设计能力则与工程创新的实现是密切相关的。为激发创造性思维，建议设计人员遵循一下准则。1. 创造性地利用所需要的物理性能和控制不需要的物理性能。 可以利用自然法则获物质的性能（例如柔性，强度，重力，惯性，浮力，离心力；杠杆原理和斜面原理，摩擦，粘性，流体压力和热膨胀）和许多电学，光学和化学现象来满足一台机器的设计要求。一种性能在某种场合下可能是有用的，而在另外一种场合下则可能是有害的。阀门的弹簧应该有柔性，而阀门的凸轮轴就不需要柔性。离合器结合面上需要有摩擦，而离合器轴承却不需要摩擦。设计时，需要创造性地利用和控制所要的物理性能，将不需要的物理性能减至最少。 2. 在重量最轻的情况下，提供合理的应力分布刚度。 对于承受交变应力的零件，应该特别主要减轻应力集中和提高圆角，螺纹和配合处的强度。改变零件的形状，可以降低它所承受的应力，对零件施加预应力，如表面滚压和浅表面硬化，均可以使其得到强化。空心轴和空心管道，箱形截面能获得有利的应力分布，同时具有强度高而重量最轻的特点。曲轴，凸轮轴以及含有轴承支座的外壳和构架都应有足够的刚度以保证直线对中精度和接触表面之间的压力均匀分布。轴和其他零件须有适当的刚度，避免产生共振。3.利用基本公式进行尺寸计算和尺寸优化。 力学和其他学科的基本公式是公认的计算依据。有时须有将这些公式进行移项而化成特殊形式，以简化尺寸的计算或者对尺寸进行优化。例如，用梁的表面应力公式来计算齿轮的轮齿尺寸。在不能采用解析法计算的情况下，可以在基本公式内引入系数。例如，对于薄壁钢管，考虑到腐蚀性，可将根据压力求得的厚度增加一些。当必须应用一个基本公式来确定形状，材料和使用条件，而这些被确定的量仅仅与在公式推导中的假设比较接近时，要采用措施使结果“偏于安全”。当数据不完全时，可以应用理论公式作为尺寸的指南，在扩展后的范围内获得令人满意的设计结果。4. 根据性能组合选择材料。 选择擦了时需要考虑有关的性能组合，不仅考虑强度，硬度和重量而且有时还要考虑抗冲击力，抗腐蚀性和耐高温或低温的能力。成本和制造性能都是应该考虑的因素，这些因素包括可焊接性，机械加工性能，对热处理温度变化的敏感性和所需要的涂层等。5. 在现有零件和整体零件之间进行认真的选择。 若一个以前研制的零件能够满足性能要求和可靠性要求，并适用于所设计的那台机器而无须附加的研制费用，那么设计人员及其公司通常会从零件制造厂的现货中选取该零件。但是，只有充分了解其性能，才能进行认真的选择工作，因为任何一个机器零件的失效都会影响公司的信誉，并使公司承担相应的责任。在其他情况下，若机器设计人员自己来设计零件，则零件的强度，可靠性和成本等方面的要求就可以更好地得到满足。可将某个零件与其他零件设计成一个整体零件，例如将几个齿轮设计为一个锻件或者将齿轮与轴设计为一体，这种方法的主要优点是紧凑。6.保证零件在装配中准确定位和不发生干涉。一个良好的设计能够保证零件定位准确，装配和修理方便容易。轴肩和导向表面在装配过程中不需要测量就能提供准确定位。零件的形状应该被设计得保证这个零件不会被装反获装错位置。必须能够预见和防止诸如不同的螺纹孔中的螺钉之间的干涉和不同的连杆机构之间的干涉。必须避免部件之间的找正对中误差和定位误差，或者必须采用措施，减少任何由此引起的不利的位移和应力。润滑剂的作用尽管润滑剂主要是用来控制摩擦和磨损的。它们能够而且通常也确实起到许多的作用，这些作用随其他用途不同而不同，但通常相互之间是有关系的。 控制摩擦力。 滑动面直接润滑剂的数量和性质对所产生的摩擦力有极大的影响。例如，不考虑热和磨损这些相关因素，只考虑两个油膜表面间的摩擦力，它能比两个同样表面，但没有润滑时小200倍。在流体膜润滑状况时摩擦力与流体的粘度成正比。一些诸如石油衍生物这类润滑剂，可以有很多中粘度，因此能够满足范围广的功能要求。在边界润滑状态，润滑剂粘度对摩擦力的影响不像其化学性质的影响哪么显著。磨损控制。磨蚀，腐蚀和固体与固体之间的接触就会造成磨损。适当的润滑剂将能帮助克服上面提到的每一种磨损现象。润滑剂通过润滑膜来增加滑动面之间的距离，从而减轻磨料污染物和表面凹凸不平造成的损伤，因此，减轻了磨蚀和由固体之间接触造成的磨损。控制温度。 润滑剂通过减少摩擦和将产生的热量带走来控制温度。其效果取决于润滑剂的作用量和外部的冷却措施。冷却剂的种类也会在较少的程度上影响表面的温度。控制腐蚀。 润滑剂在控制表面腐蚀方面有双重的作用。当机器闲置不工作时，润滑剂起到防腐剂的作用。当机器工作时，润滑剂通过给被润滑零件涂上一层可能含有添加剂，能够腐蚀材料中和的保护膜来控制腐蚀。润滑剂控制腐蚀的能力与润滑剂保留在金属表面的润滑膜的厚度和润滑剂的化学成分有直接的关系。其他作用除了减少摩擦外，润滑剂还经常有其他的用途。其中的一些用途如下所述。传递动力。润滑剂被广泛用来作为液压传动中的工作液体。绝缘。 在像变压器和配电装置这些特殊用途中，具有很高介电常数的润滑剂起电绝缘材料的作用。为了获得最高绝缘性能，润滑剂中不能含有任何杂志和水分。减震。 在像减震器这种能量传递装置中和在承受很高的间隙载荷的齿轮这样的机器零件的周围，润滑剂被作为减震液适用。密封。 润滑脂通常还有一个特殊的作用，就是形成密封层以防止润滑剂外泄和污染物进入。附件2 外文资料Cear Manufacturing MethodsPlaning the shape of space between gear teeth is complex and varies with the number of tooth on the glare as well as tooth module ,so most gear manufacruring methods generate the tooth flank instead of forming.Planing uses a reciprocaing rack, stroking in the direction of the helix on a gear with a gradual generation of form as the rack effectively rolls round the gear blank. The rack is relieved out of contact for the return stroke as in normal shaping or planing. It has the great advantage that the cutting tool is a simple rack with(nearly)straight sided teeth which can easily be ground accurately. this method is little used for high production because it is stroking rate does not matter and low tool costs give an advantage where unusual sizes or profile modifications are required.Shaping shaping is inherently similar to planing but uses a circular cutter instead of a rack and the resulting reduction in the reciprocating inertia allows much higher stroking speeds;modern shapers cutting car gears can run at cutting strokes per minute.the shape of the cutter is roughly the same as an involute gear but the tips of the teeth are rounded.Shaping shaping is inherently similar to planing but usrs a circular cutter instead of a rack and the resulting reduction in the reciprocating inertia allows much higher stroking speeds; modern shapers cutting car gears can run at cutting strokes per minute. the shape of the cutter is roughly the same as an involute gear but the tips of the teeth are rounded.The generating drive berween cutter and workpiece does not involve a rack or leadscrew since only circular motion is involved. the tool and workpiece move tangentially typically 0.5mm for wach srlke of the cutter . on the return stroke the cutter must be retracted about 1mm to give clearance otherwise tool rub occurs on the backstroke and failure is rapid.The advantages of shaping are that production rates are relatively high and that it is possible to cut right up to a shoulder. Unfortunately, for helical gears, a helical guide is required to impose a rotational motion on the stroking motion; such helical guides cannot be produced easily or chwaply so the method is only suitable for long runs with helical gears since special cutters and guides must be manufactured for each different helix angle.a great advantage of shaping is its ability to cut annular gears such as those requried for large epicyclic drives.Hobbing hobbing, the most used metal cutting method, uses the rack generating principle but avoids slow reciprocation by mounting many racks on a rotating cutter. the “racks” are displaced axiallu to form a gashed worm.Metal removal are high since no reciprocation of hob or workpiece is required and so cutting speeds of 40m/min can be used for conventional hobs and up to 150m/min for carbiide hobs.Ttypically with a 100mm diameter hob the rotation speed will be 100 rpm and so a twenty tooth workpiece will rotateat 5 rmp. Each revolution of te workpiece will correspond to 0.75 mm feed so the hob will advance through the workpiece at about 4mm per minute. For car production roughing multiple start hobs can be used with coarse feeds of per minute . For car production roughing multiple start hobs can be used with coarse feeds of 3mm per revolution so that 100 rpm on the cutter, a two-start hob and a 20 tooth gear will give a feed rate of 30mm/min.Broaching broaching is not usually used for helical gears but is useful for internal spur gears; the principle use of broaching in this context is for internal splines which cannot easily be made by any other method. As with all broaching the method is only economic for large quantities since setup costs are high.Broaching gives high accuracy and good surface finish but like all cutting processes is limited to “soft” materials which must be subsequently case-hardened or heat treated, giving distortion.Shaving shaving is used as finishing processes for gears in the “soft state. The objective is to improve surface finish and profile by mating the roughed-out gear with a “cutter” which will improve form.A shaving cutter looks like a gear which has extra clearance at the root (for swarf and coolant removal) and whose tooth flanks have been grooved to give cutting edges. It is run in mesh with the rough gear with crossed axes so that there is in theory point contact with a relative velocity along the teeth giving scraping action. The shaving cutter teeth are relatively flexible in bending and so will only operate effectively when they are in double contact between two gear teeth. The gear and cutter operate at high rotational speeds with traversing of the workface and about 100 micron of material is removed. Cycle times can be less than half a minuute and the machines are not expensive but cutters are delicate and difficult to manufacture.Grinding grinding is extremely important because it is the main way hardened gears are machined. When high accuracy is required it is required it is not sufficient to pre-correct for feat treatment distortion and grinding is then necessary.The simplest approach to grinding is form grinding. The wheel profile is dressed accurately to shape required. The profiled wheel is then reciprocated axially along the gear, when one tooth shape has been finished, involving typically 100 micron metal removal, the gear is indexed to the next tooth space. This method is fairly slow but gives high accuracy consistently. Setting up is lengthy because different dressing templates are needed if module,number of teeth, helix angle,or profile correction is changed.The fastest grinding method uses the same principle as hobbing but replaces a gashed and relieved worm by a grinding wheel which is a rack in section. Only single start worms are cut on the wheel but gear rotation speeds are high, 100 rpm typically,so it is difficult to design although there is a tendency for wheel and workpiece to deflect variably during grinding so the wheel form may require compensation for machine deflection effects. Generation of a worm shape on the grinding wheel is a slow process since a dressing diamond must not only form the rack profile but has to move axially as the wheel rotates. Once the wheel has been trued,gears can be ground rapidly until redressing is required. This is the most popular method for high production rates with small gears. Some rules for mechanical designDesigning starts with a need, real or imagined. Existing apparatus may need improvements in durability ,effciently,weight,speed,or cost. Mew apparatus may be needed to perform a function previously done by men, such as computation, assembly,or servicing. With the objective wholly or partly defined, the next step in design is the conception of mechanisms and their arrangements that will perform the needed functions. For this, freehand sketching is of great value, mot only as a record of ones thoughts and as an aid in discussion with others. But prticularly for communication with ones own mind, as a stimulant for crwative ideas.When the general shape and a few dimensions of the several components become apparent, analysis can begin in earnest. The analysis will have as its objective satisfactory or superior performance,plus safety and durability with minimum weight,and a competitive cost. Optimum proportions and dimensions will be sought for each critically loaded section, together with a balance between the strength of the several components. Materials and their treatment will be choen. These important objectives can be attained only by analysis based upon the principles of mechanics,such as those of statics for reaction forces and for the optimun utilization of friction; of dynamics for inertia,acceleration, and energy; of elasticity and strength of materials for stress and deflection; and of fluid mechanics for lubrication and hydrodynamic drives.Finlly ,a design based upon funcition and reliability will be completed,and a prototype may be built. If its tests are satisfactory, and if the device is to be produced in quantity, the initial design will undergo certain modifications that enable it to be manufactured in quantity. During subsequent years of manufacture and service, the design is likely to undergo changes as new ideas are conceived or as further analysis based upon tests and experience indicate alteration. Sales appal, customer satisfaction, and manufacture cost are all related to design ,and ability in design is intimately involved in the success of an engineering wenture.To stimulate creative thought,the following rules are suggested for the designer.1. Apply ingenuity to utilize desired physical properties and to control undesired ones. The performance requirements of a machine are met by utilizing laws of nature or properties of matter (e.g.,flexibility,strength,gravity,inertia,buoyancy,centrifugalforce,principles of the lever and inelined plane,friction,viscosity,fluid pressure,and thermal wxpansion), also themany elecrtrical,optical,and chemical phenomena. However, what may be useful in one application may be detrimental in the next. Flexibility is desired in valve springs but not in the valve camshaft; friction is desired at the clutch face but not in the clutch bearing. Ingenuity in design should be applied to utilize and control the pysical propertise that are desired and to minimize those that are not desired. 2.Provide for favorable stress distribute and stiffness with minimum weight. On components subjected to fluctuating stress,particular attention is given to reduction in stress concentration,and to an increase of strength at filltes,threads,holes,and fits. Stress reduction are made by modification in shape, and strengthening may be done by prestressing treatments such as surface rolling and shallow hardening. Hollow shafts and tubing,and box sections give a favorable stress distribution, together with sriffness and minimun weight. Sufficient stiffness to maintain alignment and uniform pressure between contacting surfaces should be provided for crank,cam,and gear shafts, and for enclosures and frames containing bearing supports. The stiffness of shafts and other components must be suitable to avoid resonant vibrations.3.Use basic equations to calculate and optimize dimensions. The fundamental equations of mechanics and the other sciences are the accepted bases for calculations. They are sometimes rearranged in special forms to facilitate the determination or optimization of dimensions,such as the beam and surface stress equations for determing gear-tooth size. Factors may be added to a fundamental equation for conditions not analytically determinable, e.g., on thin steeltubes,an allowance for corrosion asses to the thickness based on pressure. When it is necessary to apply a fundamental equation to shapes, materials,or conditions which only approximate the assumptions for its derivation,it is done in a manner which gives results “on the safe side”. In situations where data are incomplete, equations of the sciences may be used as proportioning guides to extend a satisfactory design to new capacities. 4.Choose materials for a combination of properties. Materials should be chosen for a combination of pertinent properties,not only for strength. hardness, and weight, but sometimes for resistance to impact, corrosion,and low or high temperatures. Cost and fabrication properties are factors,such as weldability,machinability,sensitivity to variation in heat-treating tenperatures, and required coating.5.Select carafully between stock and integral components. A previously developed components is frequently selected by a designer and his company form the stocks of parts manufacturers, if the component meet the performance and reliability requirements and is adaptable without additional development costs to the particular machine being designed. However ,its selection should be carefully made with a full knowledge of its properties, since the reputation and liability of the company suffer if there is a failure in any one of the machines parts. In other cases the strength,teliability,and cost requirements are better met if the designer of the machine also designs the component,with the particular advantage of compactness if it is designs integral with other components, e.g., gears to be forged in clusters integral with a shaft.6.Provide for accurate location and non-inter ference of parts in assembly. A good design provides for the correct locating of parts and for easy assernbly and repair. sholders and pilot surfaces give accurate location without measurement during assembly. Shapes can be designed so that parts cannot be assembled backwards or in the wrong place.Interferences, as between screws in tapped holes, and between linkages must be foreseen and prevended. Inaccurate alignment and positioning between such assemblies must be avoided,or provision must be made to minimize any resulting detrimental displacements and stresses. Functions of lubricantsAlthough a lubricant primarily controls friction and wear, it can and ordinarily does perform numerous other functions,which vary with the aplication and usually are interrelated. Friction control. The amount and character of the lubricant made avaliable to sliding surfaces have a profound effect upon the friction that is encountered. For example, disregarding such related factors as heat and wear but considering friction alone between two oil-film lubricated surfaces, the friction can be 200 times less than that between the same surfaces with no lubricant. Under fluid-film conditions, friction is directly proportional to the viscosity of bthe fluid. Some lubricants,such as petroleum derivatives, are available in a great range of viscosities and thus can satisfy a broad spectrum of fun
- 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。
川公网安备: 51019002004831号