【溫馨提示】 dwg后綴的文件為CAD圖，可編輯，無水印，高清圖，，壓縮包內(nèi)文檔可直接點(diǎn)開預(yù)覽，需要原稿請自助充值下載，請見壓縮包內(nèi)的文件及預(yù)覽，所見才能所得，請細(xì)心查看有疑問可以咨詢QQ：414951605或1304139763
編號：
無錫太湖學(xué)院
畢業(yè)設(shè)計（論文）
相關(guān)資料
題目： 臥式鉆孔組合機(jī)床液壓系統(tǒng)的設(shè)計
信機(jī) 系 機(jī)械工程及自動化專業(yè)
學(xué) 號： 0923156
學(xué)生姓名： 葛喬虹
指導(dǎo)教師： 許菊若（職稱：副教授 ）
（職稱： ）
2013年5月25日
目 錄
一、畢業(yè)設(shè)計（論文）開題報告
二、畢業(yè)設(shè)計（論文）外文資料翻譯及原文
三、學(xué)生“畢業(yè)論文（論文）計劃、進(jìn)度、檢查及落實表”
四、實習(xí)鑒定表
無錫太湖學(xué)院
畢業(yè)設(shè)計（論文）
開題報告
題目： 臥式鉆孔組合機(jī)床液壓系統(tǒng)的設(shè)計
信機(jī) 系 機(jī)械工程及自動化 專業(yè)
學(xué) 號： 0923156
學(xué)生姓名： 葛喬虹
指導(dǎo)教師： 許菊若 （職稱：副教授）
（職稱： ）
2012年11月30日
課題來源
導(dǎo)師提供的研究項目
科學(xué)依據(jù)（包括課題的科學(xué)意義；國內(nèi)外研究概況、水平和發(fā)展趨勢；應(yīng)用前景等）
（1） 課題科學(xué)意義
液壓傳動技術(shù)是機(jī)械設(shè)備中發(fā)展最快的技術(shù)之一，特別是近年來與微電子、計算機(jī)技術(shù)結(jié)合，使液壓技術(shù)進(jìn)入了一個新的發(fā)展階段，機(jī)、電、液、氣一體是當(dāng)今機(jī)械設(shè)備的發(fā)展方向。在一些加工的機(jī)械設(shè)備中已經(jīng)廣泛引用液壓技術(shù)。作為機(jī)械制造及其自動化專業(yè)的學(xué)生初步學(xué)會液壓系統(tǒng)的設(shè)計，熟悉分析液壓系統(tǒng)的工作原理的方法，掌握液壓元件的作用與選型及液壓系統(tǒng)的維護(hù)與修理將是十分必要的。
（2）機(jī)床的液壓傳動應(yīng)用及其發(fā)展前景
液壓傳動在國民經(jīng)濟(jì)的各個部門都得到了廣泛的應(yīng)用，但是各部門采用液壓傳動的處發(fā)點(diǎn)不盡相同：例如，工程機(jī)械、壓力機(jī)械采用液壓傳動的主要原因是取其結(jié)構(gòu)簡單、輸出力大；航空工業(yè)采用液壓傳動的主要原因是取其重量輕、體積??；機(jī)床上采用液壓傳動的主要原因則是取其在工作過程中能無級變速，易于實現(xiàn)自動化，能實現(xiàn)換向頻繁的往復(fù)運(yùn)動等優(yōu)點(diǎn)。
現(xiàn)代液壓技術(shù)與微電子技術(shù)、計算機(jī)控制技術(shù)、傳感技術(shù)等為代表的新技術(shù)緊密結(jié)合，形成并發(fā)展成為一種包括傳動、控制、檢測在內(nèi)的自動化技術(shù)。
研究內(nèi)容
① 明確設(shè)計要求及技術(shù)參數(shù)的擬定；
② 執(zhí)行元件選擇、工況分析（包括動力分析及運(yùn)動分析）、負(fù)載圖和速度圖繪制、執(zhí)行元件參數(shù)初步確定；
③ 系統(tǒng)方案確定，液壓系統(tǒng)原理圖擬訂；
④ 計算和選擇液壓元件；
⑤ 估算液壓系統(tǒng)性能；
⑥ 繪制液壓裝置系統(tǒng)圖；設(shè)計液壓裝置；
⑦編寫技術(shù)文件。
擬采取的研究方法、技術(shù)路線、實驗方案及可行性分析
（1）研究方法
進(jìn)行圖書資料和網(wǎng)絡(luò)資料的收集。首先進(jìn)行圖書資料收集，收集有關(guān)液壓傳動資料。了解液壓傳動的發(fā)展史及其當(dāng)前的應(yīng)用情況。通過資料的收集，進(jìn)一步拓寬對液壓系統(tǒng)的認(rèn)識。收集有關(guān)液壓系統(tǒng)和臥式鉆孔機(jī)床的中外文獻(xiàn)以及其他有利資料，更進(jìn)一步了解液壓系統(tǒng)，關(guān)注國內(nèi)外臥式鉆孔機(jī)床中液壓系統(tǒng)的應(yīng)用情況，認(rèn)真探索液壓系統(tǒng)應(yīng)用于臥式鉆孔機(jī)床的必要性。
（2）實驗方案
對臥式鉆孔組合機(jī)床的液壓傳動系統(tǒng)具體設(shè)計： (1)明確工作循環(huán)并做工況分析。(2)明確主機(jī)的具體性能要求，進(jìn)行負(fù)載分析和運(yùn)動分析。作出功率循環(huán)圖，協(xié)調(diào)各個元件的動作時間和速度。(3)確定液壓系統(tǒng)的主要參數(shù)：壓力和流量，參照經(jīng)驗選取。(4)擬定液壓系統(tǒng)原理圖。確定系統(tǒng)的回路方式、液壓油類型、執(zhí)行元件及液壓泵類型、調(diào)速、調(diào)壓及換向方式、“開”或“閉”式確定。(5)液壓元件選擇。(6)液壓系統(tǒng)驗算。壓力計算、系統(tǒng)容積效率計算和發(fā)熱估算。(7)液壓系統(tǒng)主要元件的設(shè)計。
研究計劃及預(yù)期成果
研究計劃：
2012年11月12日-2012年12月2日：按照任務(wù)書要求查閱論文相關(guān)參考資料，填寫畢業(yè)設(shè)計開題報告書。
2012年12月3日-2013年3月5日：填寫畢業(yè)實習(xí)報告，并開始著手畢業(yè)設(shè)計零件圖紙的分析。
2013年3月8日-2013年3月14日：按照要求修改畢業(yè)設(shè)計開題報告，同時開
始繪制工作圖，并且開始撰寫說明書。
2013年3月15日-2013年3月21日：學(xué)習(xí)并翻譯一篇與畢業(yè)設(shè)計相關(guān)的英文材
料，進(jìn)行系統(tǒng)圖的設(shè)計，繪制圖基本的圖紙。
2013年3月22日-2013年4月11日：圖紙及說明書的修改。
2013年4月12日-2013年4月25日：進(jìn)一步完善工作。
2013年4月26日-2013年5月21日：畢業(yè)論文撰寫和修改工作。
預(yù)期成果：液壓系統(tǒng)圖、裝配圖、各個零件圖以及設(shè)計說明書的完成。
特色或創(chuàng)新之處
① 采用液壓傳動來實現(xiàn)機(jī)床進(jìn)給運(yùn)動，這樣做有利于簡化機(jī)床結(jié)構(gòu)，提高機(jī)床自動化的程度。
② 液壓動力滑臺是利用液壓缸將泵站提供的液壓能轉(zhuǎn)變?yōu)榛_運(yùn)動所需的機(jī)械能，來實現(xiàn)進(jìn)給運(yùn)動并完成一定得動作循環(huán)，是一種以速度變換為主的中、低壓液壓系統(tǒng)，在高效、專用、自動化程度較高的機(jī)床中已得到廣泛的應(yīng)用。
已具備的條件和尚需解決的問題
① 實驗方案思路已經(jīng)非常明確，已經(jīng)具備了液壓系統(tǒng)基礎(chǔ)理論知識，基本機(jī)械設(shè)計能力和繪圖能力
② 學(xué)會液壓系統(tǒng)的設(shè)計，熟悉分析液壓系統(tǒng)的工作原理的方法，掌握液壓元件的作用與選型及液壓系統(tǒng)的維護(hù)與修理
指導(dǎo)教師意見
指導(dǎo)教師簽名：
年 月 日
教研室（學(xué)科組、研究所）意見
教研室主任簽名：
年 月 日
系意見
主管領(lǐng)導(dǎo)簽名：
年 月 日
英文原文
Basic Machining Operations and Cutting Technology
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 workpiece and the cutting tool and can precisely control their relative positions and the velocity of the tool with respect to the workpiece. Basically, in metal cutting, a sharpened wedge-shaped tool removes a rather narrow strip of metal from the surface of a ductile workpiece in the form of a severely deformed chip. The chip is a waste product that is considerably shorter than the workpiece from which it came but with a corresponding increase in thickness of the uncut chip. The geometrical shape of workpiece 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 workpiece 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 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 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. They can be generated by radial 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 workpiece 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 workpiece 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 to 10 times the drill diameter. Whether the
drill turns or the workpiece rotates, relative motion between the cutting edge and the workpiece is the important factor. In milling operations a rotary cutter with a number of cutting edges engages the workpiece. 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 may be used, and the feed of the workpiece 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 I 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: I turning, planning, drilling, milling, and grinding. 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; bobbing 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 I 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 workpiece or its holder and the cutting tool; 2. it provides relative motion between the workpiece and the cutting tool; 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 depth 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 (V) 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 of the needle radially inward per revolution, or is the difference in position between two adjacent grooves. The depth of cut is the penetration of the needle into the record or the depth of the grooves.
Turning on Lathe Centers
The basic operations performed on an engine lathe are illustrated. Those operations performed on external surfaces with a single point cutting tool are called turning. Except for drilling, reaming, and lapping, 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 as 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 obtain the final size, shape, and surface finish on the workpiece. Sometimes a semi-finishing operation will precede the finishing operation to leave a small predetermined and uniform amount of stock on the work-piece to be removed by the finishing operation.
Generally, longer workpieces 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 workpiece-usually along the axis of the cylindrical part. The end of the workpiece 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 workpiece may be held in a four-jaw chuck, or in a type chuck. This method holds the workpiece firmly and transfers the power to the workpiece smoothly; the additional support to the workpiece 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 workpiece accurately in the chuck.
Very precise results can be obtained by supporting the workpiece between two centers. A lathe dog is clamped to the workpiece; together they are driven by a driver plate mounted on the spindle nose. One end of the Workpiece is mecained;then the workpiece can be turned around in the lathe to machine the other end. The center holes in the workpiece serve as precise locating surfaces as well as bearing surfaces to carry the weight of the workpiece ?and to resist the cutting forces. After the workpiece has been removed from the lathe for any reason, the center holes will accurately align the workpiece back in the lathe or in another lathe, or in a cylindrical grinding machine. The workpiece 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 workpiece in the chuck, this must not be done because it is not possible to press evenly with the jaws against the workpiece 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 provide 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 workpieces are sometimes mounted on two centers, they are preferably held at the headstock end by faceplate jaws 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.
Introduction of Machining
Machining as a shape-producing method is the most universally used and the most important of all manufacturing processes. Machining is a shape-producing process in which a power-driven device causes material to be removed in chip form. Most machining is done with equipment that supports both the work piece and cutting tool although in some cases portable equipment is used with unsupported workpiece.
Low setup cost for small Quantities. Machining has two applications in manufacturing. For casting, forging, and press working, each specific shape to be produced, even one part, nearly always has a high tooling cost. The shapes that may he produced by welding depend to a large degree on the shapes of raw material that are available. By making use of generally high cost equipment but without special tooling, it is possible, by machining; to start with nearly any form of raw material, so tong as the exterior dimensions are great enough, and produce any desired shape from any material. Therefore .machining is usually the preferred method for producing one or a few parts, even when the design of the part would logically lead to casting, forging or press working if a high quantity were to be produced.
Close accuracies, good finishes. The second application for machining is based on the high accuracies and surface finishes possible. Many of the parts machined in low quantities would be produced with lower but acceptable tolerances if produced in high quantities by some other process. On the other hand, many parts are given their general shapes by some high quantity deformation process and machined only on selected surfaces where high accuracies are needed. Internal threads, for example, are seldom produced by any means other than machining and small holes in press worked parts may be machined following the press working operations.
Primary Cutting Parameters
The basic tool-work relationship in cutting is adequately described by means of four factors: tool geometry, cutting speed, feed, and depth of cut.
The cutting tool must be made of an appropriate material; it must be strong, tough, hard, and wear resistant. The tool s geometry characterized by planes and angles, must be correct for each cutting operation. Cutting speed is the rate at which the work surface passes by the cutting edge. It may be expressed in feet per minute.
For efficient machining the cutting speed must be of a magnitude appropriate to the particular work-tool combination. In general, the harder the work material, the slower the speed.
Feed is the rate at which the cutting tool advances into the workpiece. "Where the workpiece or the tool rotates, feed is measured in inches per revolution. When the tool or the work reciprocates, feed is measured in inches per stroke, Generally, feed varies inversely with cutting speed for otherwise similar conditions.
The depth of cut, measured inches is the distance the tool is set into the work. It is the width of the chip in turning or the thickness of the chip in a rectilinear cut. In roughing operations, the depth of cut can be larger than for finishing operations.
The Effect of Changes in Cutting Parameters on Cutting Temperatures
In metal cutting operations heat is generated in the primary and secondary deformation zones and these results in a complex temperature distribution throughout the tool, workpiece and chip. A typical set of isotherms is shown in figure where it can be seen that, as could be expected, there is a very large temperature gradient throughout the width of the chip as the workpiece material is sheared in primary deformation and there is a further large temperature in the chip adjacent to the face as the chip is sheared in secondary deformation. This leads to a maximum cutting temperature a short distance up the face from the cutting edge and a small distance into the chip.
Since virtually all the work done in metal cutting is converted into heat, it could be expected that factors which increase the power consumed per unit volume of metal removed will increase the cutting temperature. Thus an increase in the rake angle, all other parameters remaining constant, will reduce the power per unit volume of metal removed and the cutting temperatures will reduce. When considering increase in unreformed chip thickness and cutting speed the situation is more complex. An increase in undeformed chip thickness tends to be a scale effect where the amounts of heat which pass to the workpiece, the tool and chip remain in fixed proportions and the changes in cutting temperature tend to be small. Increase in cutting speed; however, reduce the amount of heat which passes into the workpiece and this increase the temperature rise of the chip m primary deformation. Further, the secondary deformation zone tends to be smaller and this has the effect of increasing the temperatures in this zone. Other changes in cutting parameters have virtually no effect on the power consumed per unit volume of metal removed and consequently have virtually no effect on the cutting temperatures. Since it has been shown that even small changes in cutting temperature have a significant effect on tool wear rate it is appropriate to indicate how cutting temperatures can be assessed from cutting data.
The most direct and accurate method for measuring temperatures in high -speed-steel cutting tools is that of Wright &. Trent which also yields detailed information on temperature distributions in high-speed-steel cutting tools. The technique is based on the metallographic examination of sectioned high-speed-steel tools which relates microstructure changes to thermal history.
Trent has described measurements of cutting temperatures and temperature ?distributions for high-speed-steel tools when machining a wide range of workpiece materials. This technique has been further developed by using scanning electron ?microscopy to study fine-scale microstructure changes arising from over tempering of the tempered martens tic matrix of various high-speed-steels. This technique has also been used to study temperature distributions in both high-speed -steel single point turning tools and twist drills.
Wears of Cutting Tool
Discounting brittle fracture and edge chipping, which have already been dealt with, tool wear is basically of three types. Flank wear, crater wear, and notch wear. Flank wear occurs on both the major and the minor cutting edges. On the major cutting edge, which is responsible for bulk metal removal, these results in increased cutting forces and higher temperatures which if left unchecked can lead to vibration of the tool and workpiece and a condition where efficient cutting can no longer take place. On the minor cutting edge, which determines workpiece size and surface finish, flank wear can result in an oversized product which has poor surface finish. Under most practical cutting conditions, the tool will fail due to major flank wear before the minor flank wear is sufficiently large to result in the manufacture of an unacceptable component.
Because of the stress distribution on the tool face, the frictional stress in the region of sliding contact between the chip and the face is at a maximum at the start of the sliding contact region and is zero at the end. Thus abrasive wear takes place in this region with more wear taking place adjacent to the seizure region than adjacent to the point at which the chip loses contact with the face. This result in localized pitting of the tool face some distance up the face which is usually referred to as cate