單立柱有軌巷道式堆垛機(jī)機(jī)械系統(tǒng)設(shè)計(jì)【含4張CAD圖紙】

單立柱有軌巷道式堆垛機(jī)機(jī)械系統(tǒng)設(shè)計(jì)【含4張CAD圖紙】,含4張CAD圖紙,立柱,有軌,巷道,堆垛,機(jī)械,系統(tǒng),設(shè)計(jì),CAD,圖紙 附錄 附錄1 英文原文 Definitions and Terminology of Vibration Vibration All matter-solid, liquid and gaseous-is capable of vibration, e.g. vibration of gases occurs in tail ducts of jet engines causing troublesome noise and sometimes fatigue cracks in the metal. Vibration in liquids is almost always longitudinal and can cause large forces because of the low compressibility of liquids, e.g. popes conveying water can be subjected to high inertia forces (or “water hammer”) when a valve or tap is suddenly closed. Excitation forces caused, say by changes in flow of fluids or out-of-balance rotating or reciprocating parts, can often be reduced by attention to design and manufacturing details. Atypical machine has many moving parts, each of which is a potential source of vibration or shock-excitation. Designers face the problem of compromising between an acceptable amount of vibration and noise, and costs involved in reducing excitation. The mechanical vibrations dealt with are either excited by steady harmonic forces (i. e. obeying sine and cosine laws in cases of forced vibrations) or, after an initial disturbance, by no external force apart from gravitational force called weight ( i. e. in cases of natural or free vibrations). Harmonic vibrations are said to be “simple” if there is only one frequency as represented diagrammatically by a sine or cosine wave of displacement against time. Vibration of a body or material is periodic change in position or displacement from a static equilibrium position. Associated with vibration are the interrelated physical quantities of acceleration, velocity and displacement-e. g. an unbalanced force causes acceleration (a = F/m ) in a system which, by resisting, induces vibration as a response. We shall see that vibratory or oscillatory motion may be classified broadly as (a) transient; (b) continuing or steady-state; and (c) random. Transient Vibrations die away and are usually associated with irregular disturbances, e. g. shock or impact forces, rolling loads over bridges, cars driven over pot holes-i. e. forces which do not repeat at regular intervals. Although transients are temporary components of vibration motion, they can cause large amplitudes initially and consequent high stress but, in many cases, they are of short duration and can be ignored leaving only steady-state vibrations to be considered. Steady-State Vibrations are often associated with the continuous operation of machinery and, although periodic, are not necessarily harmonic or sinusoidal. Since vibrations require energy to produce them, they reduce the efficiency of machines and mechanisms because of dissipation of energy, e. g. by friction and consequent heat-transfer to surroundings, sound waves and noise, stress waves through frames and foundations, etc. Thus, steady-state vibrations always require a continuous energy input to maintain them. Random Vibration is the term used for vibration which is not periodic, i. e. has no made clear-several of which are probably known to science students already. Period, Cycle, Frequency and Amplitude A steady-state mechanical vibration is the motion of a system repeated after an interval of time known as the period. The motion completed in any one period of time is called a cycle. The number of cycles per unit of time is called the frequency. The maximum displacement of any part of the system from its static-equilibrium position is the amplitude of the vibration of that part-the total travel being twice the amplitude. Thus, “amplitude” is not synonymous with “displacement” but is the maximum value of the displacement from the static-equilibrium position. Natural and Forced Vibration A natural vibration occurs without any external force except gravity, and normally arises when an elastic system is displaced from a position of stable equilibrium and released, i. e. natural vibration occurs under the action of restoring forces inherent in an elastic system, and natural frequency is a property of he system. A forced vibration takes place under the excitation of an external force (or externally applied oscillatory disturbance) which is usually a function of time, e. g. in unbalanced rotating parts, imperfections in manufacture of gears and drives. The frequency of forced vibration is that of the exciting or impressed force, in the forcing frequency is an arbitrary quantity independent of the natural frequency of the system. Resonance Resonance describes the condition of maximum amplitude. It occurs when the frequency of an impressed force coincides with, or is near to a natural frequency of the system. In this critical condition, dangerously large amplitudes and stresses may occur in mechanical systems but, electrically, radio and television receivers are designed to respond to resonant frequencies. The calculation or estimation of natural frequencies is, therefore, of great importance in all types of vibrating and oscillating systems. When resonance occurs in rotating shafts and spindles, the speed of rotation is known as the critical speed. Hence, the prediction and correction or avoidance3 of a resonant condition in mechanisms is of vital importance since, in the absence of damping or other amplitude-limiting devices, resonance is the condition at which a system gives an infinite response to a finite excitation. Damping Damping is the dissipation of energy from a vibrating system, and thus prevents excessive response. It is observed that a natural vibration diminishes in amplitude with time and, hence, eventually ceases owing to some restraining or damping influence. Thus if a vibration is to be sustained, the energy dissipated by damping must be replaced from an external source. The dissipation is related in some way to the relative motion between the components or elements of the system, and is caused by frictional resistance of some sort, e.g. in structures, internal friction in material, and external friction caused by air or fluid resistance called “viscous” damping if the drag force is assumed proportional to the relative velocity between moving parts. One device assumed to give viscous damping is the “dashpot” which is a loosely fitting piston in a cylinder so that fluid can flow from one side of the piston to the other through the annular clearance space. A dashpot cannot store energy but can only dissipate it. Basic Machining Operations and Machine Tools Basic Machining Operations Machine tools have evolved from the early foot-powered lathes of the Egyptians and John Wilkinson’s boring mill. They are designed to provide rigid support for both the work piece and the cutting tool and can precisely control their relative positions and the velocity of the tool with respect to the work piece. Basically, in metal cutting, a sharpened wedge-shaped tool removes a rather narrow strip of metal from the surface of a ductile work piece in the form of a severely deformed chip. The chip is a waste product that is considerably shorter than the work piece from which it came but worth a corresponding increase in thickness of the uncut chip. The geometrical shape of the machine surface depends on the shape of the tool and its path during the machining operation. Most machining operations produce parts of differing geometry. If a rough cylindrical work piece revolves about a central axis and the tool penetrates beneath its surface and travels parallel to the center of rotation, a surface of revolution is produced and the operation is called turning. If a hollow tube is machined on the inside in a similar manner, the operation is called boring. Producing an external conical surface of uniformly varying diameter is called taper turning. If the tool point travels in a path of varying radius, a contoured surface like that of a bowling pin a can be produced; or, if the piece is short enough and the support is sufficiently rigid, a contoured surface could be produced by feeding a shaped tool normal to the axis of rotation. Short tapered or cylindrical surfaces could also be contour formed. Flat or plane surfaces are frequently required. The can be generated by admiral turning or facing, in which the tool point moves normal to the axis of rotation. In other cases, it is more convenient to hold the work piece steady and reciprocate the tool across it in a series of straight-line cuts with a crosswise feed increment before each cutting stroke. This operation is called planning and is carried out on a shaper. For larger pieces it is easier to keep the tool stationary and draw the work piece under it as in planning. The tool is fed at each reciprocation. Contoured surfaces can be produced by using shaped tools. Multiple-edged tools can also be used. Drilling uses a twin-edged fluted tool for holes with depths up to 5 10times the drill diameter. Whether the drill turns or the work piece rotates, relative motion between the cutting edge and the work piece is the important factor. In milling operations a rotary cutter with a number of cutting edges engages the workspace which moves slowly with respect to the cutter. Plane or contoured surfaces may be produced, depending on the geometry of the cutter and the type of feed. Horizontal or vertical axes of rotation ma be used, and the feed of the work piece may be in any of the three coordinate directions. Basic Machine Tools Machine tools are used to produce a part of a specified geometrical shape and precise size by removing metal from a ductile material in the form of chips. The latter are a waste product and vary from long continuous ribbons of a ductile material such as steel, which are undesirable from a disposal point of view, to easily handled well-broken chips resulting from cast iron. Machine tools perform five basic metal-removal processes: turning, planning, drilling, milling, and finding. All other metal-removal processes are modifications of these five basic processes. For example, boring is internal turning reaming, tapping, and counter boring modify drilled holes and are related to drilling; hobbling and gear cutting are fundamentally milling operations; hack sawing and broaching are a form of planning and honing; lapping, super finishing, polishing, and buffing are variants of grinding or abrasive removal operations. Therefore, there are only four types of basic machine tools, which use cutting tools of specific controllable geometry: 1.lathes, 2.planers, 3.drilling machines, and 4.milling machines. The grinding process forms chips, but the geometry of the abrasive grain is uncontrollable. The amount and rate of material removed by the various machining processes may be large, as in heavy turning operations, or extremely small, as in lapping or super finishing operations where only the high spots of a surface are removed. A machine tool performs three major functions: 1.it rigidly supports the work piece or its holder and the cutting tool; 2. it provides relative motion between the work piece and the cutting tools; 3. it provides a range of feeds and speeds usually ranging from 4 to 32 choices in each case. Speed and Feeds in Machining Speeds feeds, and depth of cut are the three major variables for economical machining. Other variables are the work and tool materials, coolant and geometry of the cutting tool. The rate of metal removal and power required for machining depend upon these variables. The depths of cut, feed, and cutting speed are machine settings that must be established in any metal-cutting operation. They all affect the forces, the power, and the rate of metal removal. They can be defined by comparing them to the needle and record of a phonograph. The cutting speed is represented by the velocity of the record surface relative to the needle in the tone arm at any instant. Feed is represented by the advance the needle radically inward per revolution, or is the difference in position between two adjacent grooves. Turning on Lathe Centers The basic operations performed on an engine lathe are illustrated in Fig. Those operations performed on extremely surfaces with a single point cutting tool are called turning. Except for drilling, reaming, and tapping, the operations on internal surfaces are also performed by a single point cutting tool. All machining operations, including turning and boring, can be classified as roughing, finishing, or semi-finishing. The objective of a roughing operation is to remove the bulk of the material say rapidly and as efficiently as possible, while leaving a small amount of material on the work-piece for the finishing operation. Finishing operations are performed to brain the final size, shape, and surface finish on the work piece. Sometimes a semi-finishing operation will precede the finishing operation to leave a small predetermined and uniform amount of stood on the work-piece to be removed by the finishing operation. Generally, longer work pieces are turned while supported on one or two lathe centers. Cone shaped holes, called center holes, which fit the lathe centers are drilled in the ends of the work piece-usually along the axis of the cylindrical part. The end of the work piece adjacent to the tailstock is always supported by a tailstock center, while the end near the headstock may be supported by a headstock center or held in a chuck. The headstock end of the work piece may be held in a four-jar chuck, or in a cullet type chuck. This method holds the work piece firmly and transfers the power to the work piece smoothly; the additional support to the work piece provided by the chuck lessens the tendency for chatter to occur when cutting. Precise results can be obtained with this method if care is taken to hold the work piece accurately in the chuck. Very precise results can be obtained by supporting the work piece between two centers. A lathe dog is clamped to the work piece; together they are driven by a driver pate mounted on the spindle nose. One end of the work piece is machined; then the work piece can be turned around in the lathe to machine the other end. The center holes in the work piece serve as precise locating surfaces as well as bearing surfaces to carry the weight of the work piece and to resist the cutting forces. After the work piece has been removed from the lathe for any reason, the center holes will accurately align the work piece back in the lathe or in another lathe, or in a cylindrical grinding machine. The work piece must never be held at the headstock end by both a chuck and a lathe center. While at first thought this seems like a quick method of aligning the work piece in the chuck, this must not be done because it is not possible to press evenly with the jaws against the work piece while it is also supported by the center. The alignment provided by the center will not be maintained and the pressure of the jaws may damage the center hole, the lathe center, and perhaps even the lathe spindle. Compensating or floating jaw chucks used almost exclusively on high production work province an exception to the statements made above. These chucks are really work drivers and cannot be used for the same purpose as ordinary three or four=jaw chucks. While very large diameter work pieces are sometimes mounted on two centers, they are preferably held at the headstock end by faceplate jades to obtain the smooth power transmission; moreover, large lathe dogs that are adequate to transmit the power not generally available, although they can be made as a special. Faceplate jaws are like chuck jaws except that they are mounted on a faceplate, which has less overhang from the spindle bearings than a large chuck would have. Boring The boring operation is generally performed in two steps; namely, rough boring and finish boring. The objective of the rough-boring operation is to remove the excess metal rapidly and efficiently, and the objective of the finish-boring operation is to obtain the desired size, surface finish, and location of the hole. The size of the hole is obtained by using the trial-cut procedure. The diameter of the hole can be measured with inside calipers and outside micrometer calipers. Basic Measuring Instruments, or inside micrometer calipers can be used to measure the diameter directly. Cored holes and drilled holes are sometimes eccentric with respect to the rotation of the lathe. When the boring tool enters the work, the boring bar will take a deeper cut on one side of the hole than on the other, and will deflect more when taking this deeper cut, with the result that the bored hole will not be concentric with the rotation of the work. This effect is corrected by taking several cuts through the hole using a shallow depth of cut. Each succeeding shallow cut causes the resulting hole to be more concentric than it was with the previous cut. Before the final, finish cut is taken; the hole should be concentric with the rotation of the work in order to make certain that the finished hole will be accurately located. Shoulders, grooves, contours, tapers, and threads are bored inside of holes. Internal grooves are cut using a tool that is similar to an external grooving tool. The procedure for boring internal shoulders is very similar to the procedure for turning shoulders. Large shoulders are faced with the boring tool positioned with the nose leading, and using the cross slide to feed the tool. Internal contours can be machined using a tracing attachment on a lathe. The tracing attachment is mounted on the cross slide and the stylus follows the outline of the master profile plate. This causes the cutting tool to move in a path corresponding to the profile of the master profile plate. Thus, the profile on the master profile plate is reproduced inside the bore. The master profile plate is accurately mounted on a special slide which can be precisely adjusted in two directions, in two directions, in order to align the cutting tool in the correct relationship to the work. This lathe has a cam-lick type of spindle nose which permits it to take a cut when rotating in either direction. Normal turning cuts are taken with the spindle rotating counterclockwise. The boring cut is taken with the spindle revolving in a clockwise direction, or “backwards”. This permits the boring cut to be taken on the “back side” of the bore which is easier to see from the operator’s position in front of the lathe. This should not be done on lathes having a threaded spindle nose because the cutting force will tend to unscrew the chuck. 中文翻譯 振動(dòng)的定義和術(shù)語(yǔ) 振動(dòng) 所有的物質(zhì)---固體，液體和氣體-----都能夠振動(dòng)，例如，在噴氣發(fā)動(dòng)機(jī)尾部導(dǎo)管中產(chǎn)生的氣體振動(dòng)會(huì)發(fā)出令人討厭的噪聲，而且有時(shí)還會(huì)使金屬產(chǎn)生疲勞裂縫。液體中的振動(dòng)總是縱向的，而且由于液體的可壓縮性低，這種振動(dòng)還會(huì)產(chǎn)生很大的力。例如，當(dāng)輸水管道的閥門或水龍頭突然關(guān)閉時(shí)，管道會(huì)遭受很大的慣省性力的作用（或稱為水擊）。諸如，由于液體流動(dòng)狀態(tài)改變或者轉(zhuǎn)動(dòng)，往復(fù)運(yùn)動(dòng)零件推動(dòng)平衡所產(chǎn)生的激振力，一般可以通過(guò)對(duì)各零件的精心設(shè)計(jì)和制造來(lái)使用權(quán)其得到降低。一臺(tái)常見的機(jī)器中有許多運(yùn)動(dòng)零件，每個(gè)零件都是潛在的振動(dòng)源或沖擊激振源。設(shè)計(jì)人員需要處理好振動(dòng)與噪聲的允許值與降低激振所需要的費(fèi)用之間的關(guān)系。 所討論的振動(dòng)或者由穩(wěn)態(tài)的諧振力引起的振動(dòng)（也就是服從正弦或余弦定律的強(qiáng)迫振動(dòng)），或者是在初始擾動(dòng)之后，除了被稱為重量的重力之外，沒(méi)有其他外力引起的振動(dòng)（也就是自然或自由振動(dòng)的情況）。如果僅用一個(gè)頻率的正弦或余弦波圖形就可表示位移與時(shí)間的關(guān)系，諧振就被認(rèn)為是“簡(jiǎn)單的”。 一個(gè)物體或一種材料在振動(dòng)時(shí)，它相對(duì)于靜平衡位置的位置變化或位移是周期性的。與振動(dòng)有關(guān)的物理量是相互關(guān)聯(lián)的加速度，速度和位移。例如，一個(gè)不平衡的力在系統(tǒng)中造成的加速度（a =F/m）會(huì)因?yàn)橄到y(tǒng)的抵抗而引起振動(dòng)作為響應(yīng)?？梢钥吹?，振動(dòng)或者振蕩大致可以分為三類：（1）瞬態(tài)的，（2）連續(xù)的或穩(wěn)態(tài)的，（3）隨機(jī)的。 瞬態(tài)振動(dòng)是逐漸衰減的，而且通常與不規(guī)則的擾動(dòng)有關(guān)，例如，滾動(dòng)載荷通過(guò)橋梁，汽車通過(guò)坑洞，也就是在確定的期間內(nèi)不重復(fù)的力。盡管瞬態(tài)振動(dòng)是振動(dòng)的暫時(shí)性成分它們能夠產(chǎn)生大初始振幅和引起高的應(yīng)力。在大多數(shù)情況下，它們持續(xù)的時(shí)間很短，因而人們可以將其忽略不計(jì)而只考慮穩(wěn)態(tài)振動(dòng)。 穩(wěn)態(tài)振動(dòng)通常和機(jī)器的連續(xù)運(yùn)轉(zhuǎn)在關(guān)，而且盡管這種振動(dòng)是周期性的，但不一定是諧振或正弦振動(dòng)。由于需要能量才能產(chǎn)生振動(dòng)，因此，振動(dòng)消耗了能量，降低了機(jī)器和機(jī)構(gòu)的效率。能量的消耗有多種方式，磨擦和隨后將所產(chǎn)生的熱傳到周圍，聲波和噪聲，以及通過(guò)機(jī)架與基礎(chǔ)的應(yīng)力波等到。因此穩(wěn)態(tài)振動(dòng)總是需要連續(xù)的能量輸入來(lái)維持其存在。 隨機(jī)振動(dòng)是一個(gè)用來(lái)描述非周期性振動(dòng)的術(shù)語(yǔ)。也就是說(shuō)，這種振動(dòng)不是周期性變化的，是不定期地進(jìn)行重復(fù)的。 在下面段落中，對(duì)一些與振動(dòng)有關(guān)的術(shù)語(yǔ)和定義加以明確，其中一些可能是理科學(xué)生都已經(jīng)清楚了的。 周期，循環(huán)，頻率和振幅。 穩(wěn)態(tài)機(jī)械振動(dòng)是系統(tǒng)在一定時(shí)間范圍內(nèi)的重復(fù)運(yùn)動(dòng)，該時(shí)間范圍被稱為周期。在任何一個(gè)周期內(nèi)所完成的運(yùn)動(dòng)，被子稱為一個(gè)循環(huán)。每個(gè)單位時(shí)間內(nèi)的循環(huán)數(shù)目被稱為頻率。系統(tǒng)任何部分離開它的靜平衡位置的最大位移就是該部分振動(dòng)的振幅，總的行程是振幅的兩倍。因此，“振幅”并不是“位移”的同義詞，而是距離靜平衡位置的位移最大值。 自由振動(dòng)和強(qiáng)迫振動(dòng)。除了重力以外，在沒(méi)有任何其他作用時(shí)產(chǎn)生的振動(dòng)稱為自由振動(dòng)。通常一個(gè)彈性系統(tǒng)離開它的穩(wěn)定平衡位置后且被松開時(shí)，這個(gè)系統(tǒng)就會(huì)產(chǎn)生振動(dòng)。也就是說(shuō)，自由振動(dòng)是在彈性系統(tǒng)固有彈性恢復(fù)力的作用下產(chǎn)生的，而固有頻率則是系統(tǒng)的一個(gè)特性。 強(qiáng)迫振動(dòng)是在外力的激勵(lì)（或者外部的振蕩性干擾）下產(chǎn)生的。這個(gè)激勵(lì)或干擾通常是時(shí)間的函數(shù)。例如，在不平衡的轉(zhuǎn)動(dòng)部件中，或者是在有缺陷的齒輪和傳動(dòng)裝置中就會(huì)產(chǎn)生這種振動(dòng)。強(qiáng)迫振動(dòng)的頻率就是激振力或者外部施加的力的頻率。也就是說(shuō)，強(qiáng)迫振動(dòng)的頻率是一個(gè)與系統(tǒng)固有頻率沒(méi)有關(guān)系的任意量。 共振。共振描述了最大振幅的狀況。當(dāng)外力的頻率與系統(tǒng)的固有頻