機(jī)電-體化專業(yè)英語(yǔ)Unit 4

1、Hydraulic Machinery and Forging EquipmentPart I Technical and Practical Reading Passage A Hydraulic Machinery Hydraulic machinery is machines and tools which use fluid power to do work. In this type of machine, high-pressure liquid called hydraulic fluid is transmitted throughout the machine to vari

2、ous hydraulic motors and hydraulic cylinders. Hydraulic machinery is operated by the use of hydraulics, where a liquid is the powering medium. Pneumatics, on the other side, is based on the use of a gas as the medium for power transmission, generation and control. Force and torque multiplication A f

3、undamental feature of hydraulic systems is the ability to apply force or torque multiplication in an easy way without the need of mechanical gears or levers, either by altering the effective areas in two connected cylinders or the effective displacement between a pump and motor. Both these examples

4、are usually referred to as a hydraulic transmission or hydrostatic transmission involving a certain hydraulic gear ratio. Hydraulic circuits Open center circuits use pumps which supply a continuous flow. The flow is returned to tank through the control valves open center; that is, when the control v

5、alve is centered, it provides an open return path to tank and the fluid is not pumped to a high pressure. Closed center circuits supply full pressure to the control valves, whether any valves are actuated or not. The pumps vary their flow rate, pumping very little hydraulic fluid until the operator

6、actuates a valve. The valves spool therefore doesnt need an open center return path to tank. Multiple valves can be connected in a parallel arrangement and system pressure is equal for all valves.Open and closed circuits Open-loop: Pump-inlet and motor-return (via the directional valve) are connecte

7、d to the hydraulic tank. The term loop applies to feedback; the more correct term is open versus closed circuit. Closed-loop: Motor-return is connected directly to the pump-inlet. To keep up pressure on the low pressure side, the circuits have a charge pump that supplies cooled and filtered oil to t

8、he low pressure side. Closed-loop circuits are generally used for hydrostatic transmissions in mobile applications.Advantages: No directional valve and better response, the circuit can work with higher pressure. The pump swivel angle covers both positive and negative flow direction.Disadvantages: Th

9、e pump cannot be utilized for any other hydraulic function in an easy way and cooling can be a problem due to limited exchange of oil flow. Hydraulic pumps supply fluid to the components in the system. Pressure in the system develops in reaction to the load. Hence, a pump rated for 5,000 psi is capa

10、ble of maintaining flow against a load of 5,000 psi. Hydraulic pump Pumps have a power density about ten times greater than an electric motor (by volume). They are powered by an electric motor or an engine, connected through gears, belts, or a flexible elastomeric coupling to reduce vibration. Contr

11、ol valve Directional control valves are usually designed to be stackable, with one valve for each hydraulic cylinder, and one fluid input supplying all the valves in the stack. Directional control valves route the fluid to the desired actuator. They usually consist of a spool inside a cast iron or s

12、teel housing. The spool slides to different positions in the housing, intersecting grooves and channels route the fluid based on the spools position Notes 1、A fundamental feature of hydraulic systems is the ability to apply force or torque multiplication in an easy way without the need of mechanical

13、 gears or levers, either by altering the effective areas in two connected cylinders or the effective displacement between a pump and motor. 此句中的“eitheror”意為“或”，連接句子中的兩個(gè)并列成分，即the effective areas和 the effective displacement?！癰y”表示手段、方法。這句話的意思：液壓系統(tǒng)的一個(gè)基礎(chǔ)特征是能夠在不需要機(jī)械齒輪組或杠桿系的情況下，輕松應(yīng)用力或力矩增值。這是通過(guò)改變兩個(gè)相連汽缸間的有效

14、面積或改變泵和電機(jī)之間的有效位移來(lái)實(shí)現(xiàn)。2、To keep up pressure on the low pressure side, the circuits have a charge pump that supplies cooled and filtered oil to the low pressure side. “to keep up pressure on the low pressure side”不定式作目的狀語(yǔ)?！皌hat”引導(dǎo)定語(yǔ)從句，先行詞為“a charge pump”。整句意思：為了保持低壓側(cè)的壓力，回路有個(gè)充電泵，用以持續(xù)給低壓側(cè)提供冷卻的過(guò)濾油。3、The s

15、pool slides to different positions in the housing, intersecting grooves and channels route the fluid based on the spools position. 這是一個(gè)由and連接的并列句。兩個(gè)簡(jiǎn)單句的主語(yǔ)分別為the spool和channels，謂語(yǔ)分別為slides和route。整句意思：線軸滑向外殼及相交的凹槽中的不同位置?；诰€軸的位置，槽按路線發(fā)送水流。 1. Hydraulic machinery is a kind of machine or tool, using elect

16、rical power to do work.2. Pumps are used by closed center circuits, and the pumps provide a noncontinuous flow.3. Pump-inlet and motor-return are connected to the directional valve.4. Hydrostatic transmissions in mobile applications are often used in the closed-loop circuits.5. Directional control v

17、alves, which route the fluid to the desired actuator, are designed to be stackable. EXERCISE 1 Mark the following statements with T (True) or F (False) according to the passage. (F)(F)(F)(T)(T)1. hydraulic machinery _2. _ 動(dòng)力傳輸3. parallel arrangement _4. _ 充電泵5. swivel angle _6. _ 液壓泵7. elastomeric c

18、oupling _8. _ 功率密度 EXERCISE 2Translate the following phrases into Chinese or English. 液壓機(jī)械power transmission并聯(lián)裝置charge pump刀轉(zhuǎn)角 hydraulic pump彈性聯(lián)軸節(jié)power densityPassage B Forging Equipment Forging is the term for shaping metal by using localized compressive forces. Cold forging is done at room tempera

19、ture or near room temperature. Hot forging is done at a high temperature, which makes metal easier to shape and less likely to fracture. Warm forging is done at intermediate temperature between room temperature and hot forging temperatures. Forged parts can range in weight from less than a kilogram

20、to 170 metric tons. Hot forging Hot forging is defined as working a metal above its recrystallization temperature. The main advantage of hot forging is that as the metal is deformed the strain-hardening effects are negated by the recrystallization process. Warm forging Warm forging has a number of c

21、ost-saving advantages which underscore its increasing use as a manufacturing method. The temperature range for the warm forging of steel runs from about 800 to 1,800 degrees Fahrenheit. However, the narrower range of from 1,000 to 1,330 degrees Fahrenheit is emerging as the range of perhaps the grea

22、test commercial potential for warm forging. Compared with cold forging, warm forging has the potential advantages of: reduced tooling loads, reduced press loads, increased steel ductility, elimination of need to anneal prior to forging, and favorable as-forged properties that can eliminate heat trea

23、tment. Cold forgingCold forging is defined as working a metal below its recrystallization temperature, but usually around room temperature. If the temperature is above 0.3 times the melting temperature (on an absolute scale) then it qualifies as warm forging. Process Forging is a metal forming proce

24、ss used to produce large quantities of identical parts and to improve the mechanical properties of the metal being forged. The design of forged parts is limited when undercuts or cored sections are required. All cavities must be comparatively straight and largest at the mouth, so that the forging di

25、e may be withdrawn. The products of forging may be tiny or massive and can be made of steel (automobile axles), brass (water valves), tungsten (rocket nozzles), aluminum (aircraft structural members), or any other metal. Common forging processes include: roll forging, swaging, cogging, open-die forg

26、ing, impression-die forging, press forging, automatic hot forging and upsetting. 1. Hammer Forging: Preferred method for individual forgings. The shaping of a metal, or other material, by an instantaneous application of pressure to a relatively small area. A hammer or ram, delivering intermittent bl

27、ows to the section to be forged, applies this pressure. The hammer is dropped from itsmaximum height, usually raised by steam or air pressure. Hammer forging can produce a wide variety of shapes and sizes and, if sufficiently reduced, can create a high degree of grain refinement at the same time. Th

28、e disadvantage to this process is that finish machining is often required, as close dimensional tolerances cannot be obtained. 2. Press Forging: This process is similar to kneading, where a slow continuous pressure is applied to the area to be forged. The pressure will extend deep into the material

29、and can be completed either cold or hot. A cold press forging is used on a thin, annealed material, and a hot press forging is done on large work such asarmor plating, locomotives and heavy machinery. Press Forging is more economical than hammer forging (except when dealing with low production numbe

30、rs), and closer tolerances can be obtained. A greater proportion of the work done is transmitted to the work-piece, differing from that of the hammer forging operation, where much of the work is absorbed by the machine and foundation 3. Die Forging: Open and closed die operations can be used in forg

31、ing. In open-die forging the dies are either flat or rounded. Large forgings can be formed by successive applications of force on different parts of the material. Hydraulic presses and forging machinesare both employed in closed die forging. In closed-die forging the metal is trapped in recessed imp

32、ressions, which are machined into the top and bottom dies. As the dies press together, the material is forced to fill the impressions. Flash, or excess metal, is squeezed out between the dies. Closed-die forging can produce parts with more complex shapes than open-die forging.Die forging is the best

33、 method, as far as tolerances that can be met, and also results in a finished part that is completely filled out and is produced with the least amount of flashing. The final shape and the improvement in metallurgical properties are dependent on the skill of the operator.EXERCISE 3 Choose the best op

34、eration orders according to the information given. 1. A. Stage 1: UpsetB. Stage 2: Cant and upsetC. Stage 3: Cant and upsetD. Stage 4: DrawBDAC1. DR Differential Relay _2. ED Electron Device _3. GOR Gas Oil Ratio _4. HP High Power _ 5. H.T. Heat Treatment _ 6. HSS High Speed Steel _ 7. IG Involute G

35、ear _8. I/O Imput/Output _ EXERCISE 4Abbreviations are very useful in practical work. Read them and then translate them into corresponding Chinese terms. 差動(dòng)繼電器電子儀器電氣比大功率熱處理高速鋼漸進(jìn)開(kāi)線齒輪輸入/輸出Part II Glance at Conventional Machine Tool Structures The following is the Vice Jaw Structures。 Explanations of t

36、he Hydraulic Machine TermsNo.NameExplanation1Regenerative Hydraulic Control回饋式液壓控制2Kidney loop Filtration System過(guò)濾器3Oversized Guide & Bushings大型床身導(dǎo)軌4Ram Speeds to Spec.規(guī)格滑塊5Stroke, Shut Height to Spec.上滑塊的最大行程6Daylight to Spec.規(guī)格孔距7Ram Guide Bellows波紋式防護(hù)罩8Bolsters Machined to Spec.標(biāo)準(zhǔn)定位板9Bed Cushion/

37、Ejection Cylinder排屑槽10Quick Die Change System快速換模導(dǎo)軌11Designed for Minimal Deflection偏心凸輪12Light Curtains燈罩13Allen Bradley PLC ControlsAllen Bradley型可編程控制器14E-Stop Safety Relays急停按鈕15Operator Interface with Productivity Package操縱臺(tái)16Dual Anti-Tie Down Zero Force Palm Button死限位17Lockable Disconnect行程限位

38、18Guarding to Spec.規(guī)格防護(hù)網(wǎng)19Bolt on Metal Guards /Gates防護(hù)網(wǎng)螺栓20Digital Pressure Switch壓力傳感器21Built in Overload Protection內(nèi)置過(guò)載保護(hù)電路22Off-The Shelf JIC/NFPAJIC/NFPA現(xiàn)成保護(hù)電路23Dwell Control過(guò)壓保護(hù)24NEMA Rated EnclosuresNEMA型標(biāo)準(zhǔn)護(hù)罩25Integrated Press Safety Circuit 集成壓力保護(hù)電路26Ram Slide Position Monitoring位置傳感器27Auto-

39、Slide Lubrication System導(dǎo)軌潤(rùn)滑系統(tǒng)28Heavy Duty All-Welded Frame焊接結(jié)構(gòu)件29Pressure Lock Valves壓力控制閥30Parker Hannifin CylindersParker Hannifin型油缸31Oil Cooler散熱器EXERCISE 5The following is the Vice Jaw. After reading them, you are required to choose the suitable words or phrases given below. Flywheel Clutch an

40、d Brake Eccentric Shaft Connection Press BedSlide (Ram) Shut Height Adjustment Bolster Counterbalance Cylinder Saddle Bushing Opposed Helical Gears Each Side of Press Flywheel Clutch and Brake Opposed Helical Gears Each Side of Press Saddle Bushing Counterbalance Cylinder Press Bed Bolster Shut Heig

41、ht Adjustment Slide (Ram) Eccentric Shaft Connection Part III Simulated WritingSection A Match Your SkillThe following is the Lathe Accessories, and you can understand the name of Inner Dial Caliper Gauge. Explanations of the Toll BitsNo.NameExplanation1Adjustable Tongue Guard 可調(diào)整的舌形護(hù)罩2Flange 法蘭3Spi

42、ndle Guard主軸護(hù)罩4Eye Shield護(hù)眼罩5Work Rest工件架6Guard Cover防護(hù)板EXERCISE 6Complete the information by translating the part given in Chinese. 8 Bench Grinder Production quality grinder at hobbyist prices. Includes adjustable tool rests, eye shields, spark deflectors, medium and coarse grinding wheels.Feature

43、s: 3/4 HP motor 5/8 arbor with 1/2 adapter 3450 RPM 120V, 60 Hz, single phase; Wheel size: 8 x 3/4 x 5/8; Base size: 7-3/8 L5-1/2 W3-1/4 deep; Base mounting holes: 11/32; Overall dimensions: 16 L11-1/2 W11-14 H Weight: 25.5 lbs.Section B Have a TryThis section will help you to understand several for

44、ms of machining, and you can see the simple way a small part is produced. Cut-off - A turning operation, also known as parting, in which a single-point cut-off tool moves radially, into the side of the workpiece, and continues until the center or inner diameter of the work-piece is reached, thus par

45、ting or cutting off a section of the work-piece. A part catcher is often used to catch the removed part.External OperationsEXERCISE 7This section is to test your ability to Identifying following features of different operations. Milling (Peripheral cut) Cut-off to inner diameter Turning Cut-off to c

46、enterCut-off to centerCut-off to inner diameter Milling (Peripheral cut) Slot cut Part IV Broaden Your Horizon - Practical Activity Forging Other names / variants: ring-rolling, open-die forging, closed-die forging, drop forgingRelated processes in this database include: metal extrusion VariantsImpr

47、ession Die Forging - also called closed die forging, presses metal between 2 dies that contain a precut profile of the desired part. Cold Forging - includes bending, cold drawing, cold heading, coining, extrusions and more, to yield a diverse range of part shapes. The temperature of metals being cold forged may range from room temperature to seve