外文翻譯--機械

1、<p><b>　　附錄</b></p><p><b>　　附錄1 </b></p><p><b>　　英文原文</b></p><p>　　Rolling Contact Bearings</p><p>　　The concern of a machine d

2、esigner with ball and roller bearings is fivefold as follows:(a) life in relation to load; (b) stiffness,i.e.deflections under load; (c) friction; (d) wear; (e) noise. For moderate loads and speeds the correct selection

3、of a standard bearing on the basis of a load rating will become important where loads are high,although this is usually of less magnitude than that of the shafts or other components associated with the bearing. Where spe

4、eds are high special cooling arran</p><p>　　Because the high quality and low price of ball and roller bearing depends on quantity production,the task of the machine designer becomes one of selection rather t

5、han design. Rolling-contact bearings are generally made with steel which is through-hardened to about 900HV,although in many mechanisms special races are not provided and the interacting surfaces are hardened to about 60

6、0HV. It is not surprising that,owing to the high stresses involved,a predominant form of failure should be metal fati</p><p>　　Notwithstanding the fact that responsibility for basic design of ball and roller

7、 bearings rests with he bearing manufacturer, the machine designer must form a correct appreciation of the duty to be performed by the bearing and be concerned not only with bearing selection but with the conditions for

8、correct installation.</p><p>　　The fit of the bearing races onto the shaft or onto the housings is of critical importance because of their combined effect on the internal clearance of the bearing as well as

9、preserving the desired degree of interference fit. Inadequate interference can induce serious trouble from fretting corrosion. The inner race is frequently located axially by against a shoulder. A radius at this point is

10、 essential for the avoidance of stress concentration and ball races are provided with a radius or chamfe</p><p>　　Where life is not the determining factor in design, it is usual to determine maximum loading

11、by the amount to which a bearing will deflect under load. Thus the concept of "static load-carrying capacity" is understood to mean the load that can be applied to a bearing, which is either stationary or subje

12、ct to slight swiveling motions, without impairing its running qualities for subsequent rotational motion. This has been determined by practical experience as the load which when applied to a bearin</p><p>　　

13、The successful functioning of many bearings depends upon providing them with adequate protection against their environment, and in some circumstances the environment must be protected from lubricants or products of deter

14、ioration of the bearing design. Moreover, seals which are applied to moving parts for any purpose are of interest to tribologists because they are components of bearing systems and can only be designed satisfactorily on

15、basis of the appropriate bearing theory.</p><p>　　Notwithstanding their importance, the amount of research effort that has been devoted to the understanding of the behavior of seals has been small when compa

16、red with that devoted to other aspects of bearing technology.</p><p><b>　　Lathes </b></p><p>　　Lathes are widely used in industry to produce all kinds of machined parts. Some are gen

17、eral purpose machines, and others are used to perform highly specialized operations.</p><p>　　Engine lathes</p><p>　　Engine lathes, of course, are general-purpose machine used in production and

18、maintenance shop all over the the world. Sized ranger from small bench models to huge heavy duty pieces of equipment. Many of the larger lathes come equipped with attachments not commonly found in the ordinary shop, such

19、 as automatic shop for the carriage.</p><p>　　Tracer or Duplicating Lathes</p><p>　　The tracer or duplicating lathe is designed o produce irregularly shaped parts automatically. The basic operat

20、ion of this lathe is as fallows. A template of either a flat or three-dimensional shape is placed in a holder. A guide or pointer then moves along this shape and its movement controls that of the cutting tool. The duplic

21、ation may include a square or tapered shoulder, grooves, tapers, and contours. Work such as motor shafts, spindles, pistons, rods, car axles, turbine shafts, and a variet</p><p>　　Turret Lathes</p>&l

22、t;p>　　When machining a complex workpiece on a general-purpose lathe, a great deal of time is spent changing and adjusting the several tools that are needed to complete the work. One of the first adaptations of the eng

23、ine lathe which made it suitable to mass production was the addition of multi-tool in place of the tailstock. Although most turrets have six stations, some have as many as eight.</p><p>　　High-production tur

24、ret lathes are very complicated machines with a wide variety of power accessories. The principal feature of all turret lathes, however, is that the tools can perform a consecutive serials of operations in proper sequence

25、. Once the tools have been set and adjusted, little skill is require to run out duplicate parts.</p><p>　　Automatic Screw Machine</p><p>　　Screw machines are similar in construction to turret la

26、thes, except that their heads are designed to hold and feed long bars of stock. Otherwise, their is little different between them. Both are designed for multiple tooling, and both have adaptations for identical work. Ori

27、ginally, the turret lathe was designed as a chucking lathe for machining small casting, forgings, and irregularly shaped workpieces.</p><p>　　The first screw machines were designed to feed bar stock and wire

28、 used in making small screw parts. Today, however, the turret lathe is frequently used with a collect attachment, and the automatic screw machine can be equipped with a chuck to hold castings.</p><p>　　The s

29、ingle-spindle automatic screw machine, as its name implies, machines work on only one bar of stock at a time. A bar 16 to 20 feet long is feed through the headstock spindle and is held firmly by a collect. The machining

30、operations are done by cutting tools mounted on the cross slide. When the machine is in operation, the spindle and the stock are rotated at selected speeds for different operations. If required, rapid reversal of spindle

31、 direction is also possible.</p><p>　　In the single-spindle automatic screw machine, a specific length of stock is automatically fed through the spindle to a machining area. At this point, the turret and cr

32、oss slide move into position and automatically perform whatever operations are required. After the machined piece is cut off, stock is again fed into the machining area and the entire cycle is repeated.</p><p&

33、gt;　　Multiple-spindle automatic screw machines have from four to eight spindles located around a spindle carrier. Long bars of stock, supported at the rear of the machine,pass though these hollow spindles and are gripped

34、 by collects. With the single spindle machines, the turret indexes around the spindle. When one tool on the turret is working, the others are not. With a multiple spindle machine, however, the spindle itself index. Thus

35、the bars of stock are carried to the various end working and side</p><p>　　Vertical Turret Lathes </p><p>　　A vertical turret is basically a turret lathe that has been stood on its headstock end

36、. It is designed to perform a variety of turning operations. It consists of a turret, a revolving table, and a side head with a square turret for holding additional tools. Operations performed by any of the tools mounted

37、 on the turret or side head can be controlled through the use of stops.</p><p>　　Machining Centers</p><p>　　Many of today's more sophisticated lathes are called machining centers since they

38、are capable of performing, in addition to the normal turning operations, certain milling and drilling operations. Basically, a machining center can be thought of as being a combination turret lathe and milling machine. A

39、dditional features are sometimes included by the versatility of their machines.</p><p>　　Numerical Control</p><p>　　One of the most fundamental concepts in the area of advanced manufacturing tec

40、hnologies is numerical control(NC). Prior to the advent of NC, all machine tools were manually operated and controlled. Among the many limitations associated with manual control machine tools, perhaps none is more promin

41、ent than limitation of operator skills. With manual control, the quality of the product is directly related to and limited to the skills of the operator. Numerical control represents the first major ste</p><p&

42、gt;　　Numerical control means the control of machine tools and other manufacturing systems through the use of prerecorded, written symbolic instructions. Rather than operating a machine tool, an NC technician tool to be n

43、umerically controlled, it must be interfaced with a device for accepting and decoding the programmed instructions, known as a reader.</p><p>　　Numerical control was developed to overcome the limitation of hu

44、man operators, and it has done so. Numerical control machines are more accurate than manually operated machines, they can produce parts more uniformly, they are faster, and the long-run tooling costs are lower. The devel

45、opment of NC led to the development of several other innovations in manufacturing technology:</p><p>　　Electrical discharge machining.</p><p>　　Laser cutting.</p><p>　　3. Electron b

46、eam welding.</p><p>　　Numerical control has also made machines tools more versatile than their manually operated predecessors. An NC machine tool can automatically produce a wide variety of parts, each invol

47、ving an assortment of widely varied and complex machining processes. Numerical control has allowed manufacturers to undertake the production of products that would not have been feasible from an economic perspective usin

48、g manually controlled machine tools and processes.</p><p>　　Like so many advanced technologies, NC was born in the laboratories of the Masschusetts Institute of Technology. The concept of NC was developed in

49、 early 1950s with funding provided by the U.S.Air force. In its earliest stages, NC machines were able to make straight cuts efficiently and effectively.</p><p>　　However,curved paths were a problem because

50、the machine tool had to be programmed to undertake a series of horizontal and vertical steps to produce a curve. The shorter is straight lines making up the steps, the smoother is the curve. Each line segment in the step

51、s had to be calculated.</p><p>　　This problem led to the development in 1959 of the Automatically Programmed Tools(APT) language. This is a special programming language for NC that uses statements similar to

52、 English language to define the part geometry, describe the cutting tool configuration, and specify the necessary motions. The development of the APT language was a major step forward in the further development of NC tec

53、hnology. The original NC systems were vastly different from those used today. The machines had hardwired l</p><p>　　A major problem wad the fragility of the punched paper tape medium. It was common for the p

54、aper tape containing the programmed instructions to break or tear during a machining process. This problem was exacerbated by the fact that each programmed instructions had to be return through the reader. If it was nece

55、ssary to produce 100 copies of a given part,it was also necessary to run the paper tape through the reader 100 separate times. Fragile paper tapes simply could not withstand the rigors of a</p><p>　　This led

56、 to the development of a special magnetic plastic tape. Whereas the paper tape carried the programmed instructions as a series of holes punched in the tape, the plastic tape carried the instructions as a series of magnet

57、ic dots. The plastic tape was much stronger than the paper taps, which solved the problem of frequent tearing and breakage. However, it still left two other problems.</p><p>　　The most important of these was

58、 that it was difficult or impossible to change the instructions entered on the tape. To make even the most minor adjustments in a program of instructions, it necessary to interrupt machining operations and make a new tap

59、e. It was also still necessary to run the tape through the reader as many times as there were parts to be produced. Fortunately, computer technology became a reality and soon solved the problem of NC associated with punc

60、hed paper and plastic tape.</p><p>　　The development of a concept known as direct numerical control(DNC)solved the paper and plastic tape problems associated with numerical control by simply eliminating tape

61、 as the medium for carrying the programmed instructions. In direct numerical control machine tools are tied, via a data transmission link, to a host computer. Programs for operating the machine tools are stored in the ho

62、st computer and fed to the machine tool as needed via the data transmission linkage. Direct numerical control </p><p>　　The development of the microprocessor allowed for the development of programmable logic

63、 controllers(PNC)and microcomputer. These two technologies allowed for the development of computer numerical control(CNC). With CNC, each machine tool has a PLC or a microcomputer that serves the same purpose. This allow

64、s programs to be input and stored at each individual machine tool. It also allows programs to be developed off-line and download at the individual machine tool. CNC solved the problems associat</p><p>　　CNC

65、machine tool feed motion systems</p><p>　　CNC machine tool feed motion systems, especially to the outline of the control of movement into the system, must be addressed to the movement into the position and v

66、elocity at the same time the realization of two aspects of automatic control, as compared with the general machine tools, require more feed system high positioning accuracy and good dynamic response. A typical closed-loo

67、p control of CNC machine tool feed system, usually by comparing the location of amplification unit, drive unit, mec</p><p>　　Linear Roller Guides</p><p>　　In order to meet these requirements, th

68、e use of CNC machine tools in general low-friction transmission vice, such as anti-friction sliding rail, rail rolling and hydrostatic guideways, ball screws, etc.; transmission components to ensure accuracy, the use of

69、pre-rational, the form of a reasonable support to enhance the stiffness of transmission; deceleration than the best choice to improve the resolution of machine tools and systems converted to the driveshaft on the reducti

70、on of inertia; as far</p><p>　　Linear Roller Guides outstanding advantage is seamless, and can impose pre-compression. By the rail body, the slider, ball, cage, end caps and so on. Also known as linear rolli

71、ng guide unit. Use a fixed guide body without moving parts, the slider fixed on the moving parts. When the slider moves along the rail body, ball and slider in the guide of the arc between the straight and through the ro

72、lling bed cover of Rolling Road, from the work load to non-work load, and then rolling back work load, c</p><p>　　Bridge Crane</p><p>　　Bridge crane is having an elevated track running in a brid

73、ge-type crane, also known as the crane. Bridge Crane in the laying of the bridge on both sides along the elevated track on the vertical run, lifting trolley along the bridge laying on the track in the horizontal operatio

74、n, a scope of work of a rectangle, it can take full advantage of having the space below lifting materials from the ground equipment hindered. </p><p>　　Bridge Crane widely used in indoor warehouses, factorie

75、s, wharves and open storage yard and other places. Able to carry items, stood up, lifting status, and adjust operations, mainly for the workshop, sections and steel production lines yard, etc.. Lifting capacity usually i

76、n the 10 to 100 t. Bridge crane itself for horizontal movement, the winch frame for the vertical movement of the winch suspended from the hook for vertical movement, the direction of movement of three of the crane can wo

77、rk. I</p><p>　　Ordinary general overhead crane from lifting trolley, having run institutions, having composed of a metal structure. Lifting up from the car and from institutions, agencies and the car running

78、 small frame consists of three parts. </p><p>　　Lifting bodies, including the motor, brakes, reducer, and the pulley drum group. Motor through the reducer, driven rotating drum so that the wire rope around 4

79、2.50 or 42.50 down to lifting weights. Small frame is from the brackets and install or run agencies and institutions, such as car parts rack, usually welded structure. </p><p>　　Crane running the driving mod

80、e can be divided into two categories: one category is the concentrated drive, which uses a motor-driven initiatives on both sides of the drive shaft driven wheel; were driven to another, that is, on both sides of the ini

81、tiative the wheels with a motor drive. Small, medium and larger overhead crane with brake, and motor reducer combination into one of the "triple play" drive, the weight of the ordinary from the overhead crane f

82、or easy installation and adjustment, ofte</p><p>　　Crane normally used only four active and driven wheels, if a great weight, increase common approach to reduce wheel round pressure. When more than four whee

83、ls, must adopt a balanced hinged frame device so that the crane load evenly distributed in the wheels. </p><p>　　Bridge metal structure from the main sorghum and sorghum-composed of the main beam is divided

84、into single-and double-girder bridge having two categories. Single-beam bridge from the main beam and a single on both sides of the span at the end of sorghum, dual-beam bridge by the two main sorghum and sorghum-compone

85、nt. </p><p>　　Liang Liang Gang and the end of the link-beam ends with wheels, for supporting an elevated bridge in the running. A main beam welding on track for the lifting trolley running. Having the struct

86、ure of the main beam type is more a typical box structure, the four truss structure and fasting truss structure. </p><p>　　Box structure can be divided into two-track box girder, partial double-track box-bea

87、m, single-bias-rail box and several main sorghum. Dual-track box girder is the extensive use of a basic form, the main beam from the upper and lower flange on both sides of the plate and vertical web composition, layout

88、rail car in the center of the flange plates online, and its simple structure , manufacturing convenient, suitable for mass production, but larger forces. </p><p>　　Partial tracks box-girder and partial doubl

89、e-track box-section of the main beam are from the upper and lower ranges flange plates and thick web of the main components, rail car in the main web layout above, the short Xiangbenna omit the stiffening plate, which tr

90、acks box-side main beam from a wide flange box instead of the main sorghum two main sorghum, respect smaller, but more complex manufacturing. </p><p>　　4 truss-type structure from four plane truss structure

91、into a closed space, in the general level of the surface Truss shops follow plate, light weight, rigidity, but compared with other structures, and its dimensions, creating more complex, fatigue lower intensity, has been

92、less productive. </p><p>　　Partial fasting truss structure similar to the main tracks box-girder from the four components of a closed steel structure, in addition to the main web for the Solid shaped beam, t

93、he other three plate in accordance with the design requirements cut into many windows, forming a no-ramps Fasting Truss, in the lower level of the surface occupied by taking truss plate, cranes and the operation of elect

94、rical equipment installed in the bridge house, lighter forces, the overall stiffness, and that in Ch</p><p>　　General overhead crane used mainly driven power, the general is in the driver indoor manipulation

95、, but also remote control. From the weight of up to 500 tons, up to 60 m span. </p><p>　　Simple beam bridge crane known as sorghum cranes, and the structure and composition of ordinary bridge crane similar t

96、o a weight, span and speed are smaller. Bridge is the main sorghum or other steel I-beam and plate steel girder section composed of simple, hand-pull or electric hoist accompanied by gourd simple as lifting trolley car,

97、the car usually in the word sorghum run on the next flange . Bridge can be elevated along the orbit, but also along the elevated suspension in the following orbit</p><p>　　Metallurgical dedicated bridge cran

98、e in the steel production process can be involved in a specific process operation, and its basic structure and general overhead crane similar, but in small vehicles are equipped with lifting the work of special agencies

99、or devices. This feature is the work of a crane used frequently, poor, working-level higher. Dual-beam bridge crane factories on the track along the vertical direction of movement, the lateral movement and trolley moveme