【導(dǎo)讀】本次設(shè)計(jì)主要是完成對(duì)液壓上料機(jī)原理的設(shè)計(jì)與液壓缸的設(shè)計(jì)?，F(xiàn)各種機(jī)械的傳動(dòng)和自動(dòng)控制的學(xué)科。液壓技術(shù)自18世紀(jì)末英國制成世界上第。業(yè)機(jī)械、汽車等行業(yè)中逐步推廣。本世紀(jì)60年代以來，隨著原子能、空間技術(shù)、是當(dāng)前液壓傳動(dòng)及控制技術(shù)發(fā)展和研究的方向。它是利用各種元件組成所需要的各種控制回路，再由若干回路有機(jī)組合。成能完成一定控制功能的傳動(dòng)系統(tǒng)來進(jìn)行能量傳遞，轉(zhuǎn)換和控制。液壓傳動(dòng)及其控制技術(shù)，就首先要了解組成系統(tǒng)的各類元件的結(jié)構(gòu)，工作原理，行液壓傳動(dòng)控制系統(tǒng)的設(shè)計(jì)。它們對(duì)保證液壓系統(tǒng)可靠和穩(wěn)定地工作有重大作用。率，這時(shí)僅受到機(jī)械強(qiáng)度和密封技術(shù)的限制。在典型情況下，發(fā)電機(jī)和電動(dòng)機(jī)的。調(diào)速，傳動(dòng)比可達(dá)100：1至2021：1。復(fù)雜的程序動(dòng)作和遠(yuǎn)程控制。此外，流動(dòng)傳動(dòng)還具有傳遞運(yùn)動(dòng)均勻平穩(wěn)，反應(yīng)速。在工業(yè)生產(chǎn)的各個(gè)部門應(yīng)用液壓傳動(dòng)技術(shù)的出發(fā)點(diǎn)是不盡相同的。到了很大的發(fā)展，并滲透到各個(gè)工業(yè)領(lǐng)域中去。

　　

【正文】 e subject to wear. As does a mechanical control, an electromechanical control uses switches, relays, times counters, and so on, to construct logic, it is faster and more flexible. The controllers using electromechanical control are called relay devices. The values in the express the relative tool distance from the home position. This distance is shown in the relative or incremental coordinates, U and W. when reading the values in the not possible to know directly how far the tool is from the part origin. Just how far it is from the home position. mounted on exhaust ports of air valves and actuators to reduce noise and prevent operating personnel from possible injury resulting not only from exposure to noise but also from high— speed airborne sign of the coordinates is zero or negative because the tool cannot move farther than the machine origin . thus at present , the values are zero so the tool is at the home position. The values in the are normally used when setting up the tools in order to find the real tool distances from the part origin. 無錫職業(yè)技術(shù)學(xué)院 畢業(yè)論文 第 27 頁 共 41 頁 The values in the absolute position express the absolute tool distance from the part origin. This distance is shown in shown in absolute coordinates, x and z .the sign may be positive or negative, depending on the quadrants in which the tool is moving. because of the pressibility of air， it is impossible to obtain precise controlled actuator velocities with pneumatic systems． also， precise positioning control is not obtainable． While pneumatic pressures are quite so far is to good. This is an important piece of information for the operator when maching, since any value in the absolute position is directly related to the part. The secret of hydraulic system’s SUCCESS and widespread use is its versatility and manageability． Fluid power is not hindered by the geometry operations when the potential difference between the tool and the work piece is sufficiently high, a transient spark discharges through the fluid, removing a very small amount of metal from the work piece of the machine as is the ease in mechanical systems． Also， power can be transmitted in almost limitless quantities because fluid systems are not so limited by the physical 1imitations of materials as are the electrical systems． For example， the performance of an electromag is limited by The saturation limit of steel． On the other hand， the power limit of fluid systems is 1imited only by the strength capacity of the material． In the express the relative tool distance from the home position. This distance is shown in the relative or incremental coordinates, U and W. when reading the values in the not possible to know directly how far the tool is from the part origin. Just how far it is from the home position. The sign of the coordinates is zero or negative because the tool cannot move farther than the machine origin . thus at present , the values are zero so the tool is at the home position. The values in the are normally used when setting up the tools in order to find the real tool distances from the part origin. Industry is going to depend more and more on automation in order to increase productivity． This includes remote and direct control of production operations，manufacturing processes。 and materials handling． Fluid power is the muscle of automation because of advantages in the following four major categories． 1． Ease and accuracy of contr01． By the use of Simple levers and push but tons，the operator of a flu id power system Call readily start， stop， speed up or slow down，無錫職業(yè)技術(shù)學(xué)院 畢業(yè)論文 第 28 頁 共 41 頁 and position forces which provide any desired horsepower With tolerances as precise as one ten— thousandth Of an inch． Fig． 13— 1 shows a fluid power system which allows all aircraft pilot to raise and lower his landing gear． When the pi lot moves a small contr01 valve in one direction， oil under pressure flows to one end of the cylinder to lower the landing gear． To retract the landing gear， the pilot moves the valve lever in the opposite direction， a110wlng 0il to flow into the other end of the cylinder． 2． Multiplication of force． A fluid power system(without using cumbersome gears， pulleys， and levers)Can multiply forces Simply and efficiently from a fraction of an ounce to several hundred tons of output． 3． Constant force or torque． Only fluid power systems are capable of providing constant force or torque regardless of speed changes． This is acplished whether the work output moves a few inches per hour， several hundred inches per minute， a few revolutions per hour． or thousands of revolutions per minute． 4． Simplicity， safety， economy． general， fluid power systems use fewer moving parts than parable mechanical or electrical systems． Thus， they ale simpler to maintain and operate． This， in turn， maximizes safety，pactness， and reliability． For example， a new power steering contr01 designed has made all other kinds of power systems obsolete on many off— highway vehicles． The Steering unit consists of a manually operated directional control valve and meter in a single body． transportation， marine technology， and offshore gas and petroleum exploration． In short， very few people get through a day of their 1ives without somehow benefiting from the technology of hydraulics2． Because the steering unit is fully fluid 1inked， mechanical linkages， universal joints。 bearings，reduction gears， etc． are eliminated． This provides a simple， pact system． In addition， very little input torque is required to produce the control needed for the toughest applications． This is important where 1imitations of control space require a small steering wheel and it bees necessary to reduce operator fatigue． There are several types of shaft couplings。 their characteristics depen