液压与气压系统中英文对照学习资料.docx

1、液压与气压系统中英文对照学习资料Hydraulic System液压与气压系统【中英文对照】Hydraulic SystemThere are only three basic methods of transmitting power：Electrical，mechanicaland fluid powerMost applications actually use a combination of the three methods to obtain the most efficient overall systemTo properly determine which principl

2、e method to use。it is important to know the salient features of each typeFor example，fluid systems call transmit power more economically Over greater distances than Can mechanical typesHowever。fluid systems arerestricted to shorter distances than are electrical systemsHydraulic power transmission sy

3、stem ale concerned with the generation, modulation, and control of pressure and flow and ,and in general such systems include: 1Pumps which convert available power from the prime mover to hydraulic power at the actuator2Valves which control the direction of pump-flow，the level of power produced，and

4、the amount of fluid一一flow to the actuatorsThe power level is determined by controlling both the flow and pressure level3Actuators which convert hydraulic power to usable mechanical power Output at the point required4The medium，which is a liquid，provides rigid transmission and control as well as 1ubr

5、ication of component s，sealing in valvesand cooling of the system5Connectors which link the various system components，provide power conductors for the fluid under pressure，and fluid flow return to tank(reservoir) 6、Fluid storage and conditioning equipment which ensure sufficient quality and quantity

6、 as well as cooling of the fluid7、pneumatics systems required a lubricator to inject。a very fine mist of oil into the air discharging from the pressure regulatorThis prevents wear of the closely fitting moving parts of pneumaticHydraulic systems ale used in industrial applications such as stamping p

7、resses，steel mills，and general manufacturing，agricultural machines，mining industry，aviation，space technology，deepsea exploration, transportation，marine technology，and offshore gas and petroleum explorationIn short，very few people get through a day of their 1ives without somehow benefiting from the t

8、echnology of hydraulics2The principle of electrical-discharge machining also called electro is or spark-erosion machining, is based on the erosion of metals by spark discharges. We know that when two current-conduct in wires are allowed to touch each other, an arc is produced. If we look closely at

9、the point of contact between the two wires, we note that a small portion of the metal has been eroded away, leaving a small crater.The basic EDM system consists of a shape tool and the workpiece, connected to a dc power supply and placed in a dielectric fluid this is one of the most widely used mach

10、ining processes, particularly for die-sinking 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 workpiece surface. The capacitor discharge is repeated at ra

11、tes of between 50,with voltages usually ranging between 50vand 380v and currents from 0.1A to 500A.Mechanical control includes cams and governors. Although they have been used for the control of very complex machines, to be cost effectively, today they are used for simple and fixed-cycle task contro

12、l. Some automated machines, such as screw machines, still use cam-based control. Mechanical control is difficult to manufacture and is subject to wear.Pneumatic control is still very popular for certain applications. It uses compressed air, valves, and switchs to construct simple control logic, but

13、is easily slow. Because standard compaonents are used to construct the logic, it is easier to build than a mechanical control . Pneumatic control parts are subject to wear.As does a mechanical control, an electromechanical control uses switches, relays, times counters, and so on, to construct logic,

14、 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 possib

15、le 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 highspeed airborn

16、e particles.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

17、 from the part origin.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 compressib

18、ility of air，it is impossible to obtain precise controlled actuator velocities with pneumatic systemsalso，precise positioning control is not obtainableWhile 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 th

19、e absolute position is directly related to the part.The secret of hydraulic systems SUCCESS and widespread use is its versatility and manageabilityFluid power is not hindered by the geometry operations when the potential difference between the tool and the work piece is sufficiently high, a transien

20、t 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 systemsAlso，power can be transmitted in almost limitless quantities because fluid systems are not so limited by the physical 1imitations of materials as are the

21、 electrical systemsFor example，the performance of an electromagnet is limited by The saturation limit of steelOn 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

22、 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

23、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 product

24、ivityThis includes remote and direct control of production operations，manufacturing processes。and materials handlingFluid power is the muscle of automation because of advantages in the following four major categories1Ease and accuracy of contr01By the use of Simple levers and push but tons，the opera

25、tor of a flu id power system Call readily start，stop，speed up or slow down，and position forces which provide any desired horsepower With tolerances as precise as one tenthousandth Of an inchFig131 shows a fluid power system which allows all aircraft pilot to raise and lower his landing gearWhen the

26、pi lot moves a small contr01 valve in one direction，oil under pressure flows to one end of the cylinder to lower the landing gearTo retract the landing gear，the pilotmoves the valve lever in the opposite direction，a110wlng 0il to flow into the other end of the cylinder2Multiplication of force A flui

27、d 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 output3Constant force or torqueOnly fluid power systems are capable of providing constant force or torque regardless of speed changesThis

28、 is accomplished whether the work output moves a few inches per hour，several hundred inches per minute，a few revolutions per houror thousands ofrevolutions per minute4Simplicity，safety，economygeneral，fluid power systems use fewer moving parts thancomparable mechanical or electrical systemsThus，they

29、ale simpler to maintain and operateThis，in turn，maximizes safety，compactness，and reliabilityFor example，a new power steering contr01 designed has made all other kinds of power systems obsolete on manyoffhighway vehiclesThe Steering unit consists of a manually operated directional control valve and m

30、eter in a single bodytransportation，marine technology，and offshore gas and petroleum explorationIn short，very few people get through a day of their 1ives without somehow benefiting from the technology of hydraulics2Because the steering unit is fully fluid 1inked，mechanical linkages，universal joints。

31、bearings，reduction gears，etcare eliminatedThis provides a simple，compact systemIn addition，very little input torque is required to produce the control needed for the toughest applicationsThis is important where 1imitations of control space require a small steering wheel and it becomes necessary to r

32、educe operator fatigue There are several types of shaft couplings; their characteristics depend on the prupose for which they are used. If an exceptionally long shaft is required for a line shaft in the manufacturing plant or a propeller shaft on ship, it is made in sections that are coupled together with rigid couplings. Additional benefits of fluid power systems include instantly reversible motion。automaticprotection against overloads，and infinitely variable speed contr01Fluid power systems also have the highest horsepower per weight rati0