【正文】 lar cast iron and provides a heavy, rigid frame on which all the other basic ponents are sets of parallel, longitudinal ways, inner and outer, are contained on the bed, usually on the upper makers use an inverted Vshape for all four ways, whereas others utilize one inverted V and one flat way in one or both several other ponents are mounted and/or move on the ways they must be made with precision to assure accuracy of , proper precaution should be taken in operating a lathe to assure that the ways are not inaccuracy in them usually means that the accuracy of the entire lathe is ways on most modern lathes are surface hardened to offer greater resistance to wear and headstock is mounted in a fixed position on the inner ways at one end of the lathe provides a powered means of rotating the work at various consists, essentially, of a hollow spindle, mounted in accurate bearings, and a set of transmission gearssimilar to a truck transmissionthrough which the spindle can be rotated at a number of lathes provide from eight to eighteen speeds, usually in a geometric ratio, and on modern lathes all the共 14 頁 第 1 頁┊ ┊ ┊ ┊ ┊ ┊ ┊ ┊ ┊ ┊ ┊ ┊ ┊ 裝 ┊ ┊ ┊ ┊ ┊ 訂 ┊ ┊ ┊ ┊ ┊ 線 ┊ ┊ ┊ ┊ ┊ ┊ ┊ ┊ ┊ ┊ ┊ ┊ ┊畢業(yè)設計（論文）報告紙speeds can be obtained merely by moving from two to four increasing trend is to provide a continuously variable speed range through electrical or mechanical the accuracy of a lathe is greatly dependent on the spindle, it is of heavy construction and mounted in heavy bearings, usually preloaded tapered roller or ball longitudinal hole extends through the spindle so that long bar stock can be fed through size of this hole is an important size dimension of a lathe because it determines the maximum size of bar stock that can be machined when the material must be fed through the inner end of the spindle protrudes from the gear box and contains a means for mounting various types of chucks, face plates, and dog plates on small lathes often employ a threaded section to which the chucks are screwed, most large lathes utilize either camlock or keydrive taper provide a largediameter taper that assures the accurate alignment of the chuck, and a mechanism that permits the chuck or face plate to be locked or unlocked in position without the necessity of having to rotate these heavy is supplied to the spindle by means of an electric motor through a Vbelt or silentchain modern lathes have motors of from 5 to 15 horsepower to provide adequate power for carbide and ceramic tools at their high cutting tailstock assembly consists, essentially, of three lower casting fits on the inner ways of the bed and can slide longitudinally thereon, with a means for clamping the entire assembly in any desired upper casting fits on the lower one and can be moved transversely upon it on some type of keyed transverse motion permits aligning the tailstock and headstock spindles and provides a method of turning third major ponent of the assembly is the tailstock is a hollow steel cylinder, usually about 2 to 3 inches in diameter, that can be moved several inches longitudinally in and out of the upper casting by means of a handwheel and open end of the quill hole terminates in a Morse taper in which a lathe center, or various tools such as drills, can be graduated scale, several inches in length, usually is engraved on the outside of the quill to aid in controlling its motion in and out of the upper locking device permits clamping the quill in any desired carriage assembly provides the means for mounting and moving cutting 共 14 頁 第 2 頁┊ ┊ ┊ ┊ ┊ ┊ ┊ ┊ ┊ ┊ ┊ ┊ ┊ 裝 ┊ ┊ ┊ ┊ ┊ 訂 ┊ ┊ ┊ ┊ ┊ 線 ┊ ┊ ┊ ┊ ┊ ┊ ┊ ┊ ┊ ┊ ┊ ┊ ┊畢業(yè)設計（論文）報告紙carriage is a relatively flat Hshaped casting that rests and moves on the outer set of ways on the transverse bar of the carriage contains ways on which the cross slide is mounted and can be moved by means of a feed screw that is controlled by a small handwheel and a graduated the cross slide a means is provided for moving the lathe tool in the direction normal to the axis of rotation of the most lathes the tool post actually is mounted on a pound consists of a base, which is mounted on the cross slide so that it can be pivoted about a vertical axis, and an upper upper casting is mounted on ways on this base so that it can be moved back and forth and controlled by means of a short lead screw operated by a handwheel and a calibrated and powered motion for the carriage, and powered motion for the cross slide, is provided by mechanisms within the apron, attached to the front of the movement of the carriage along the bed is effected by turning a handwheel on the front of the apron, which is geared to a pinion on the back pinion engages a rack that is attached beneath the upper front edge of the bed in an inverted impart powered movement to the carriage and cross slide, a rotating feed rod is feed rod, which contains a keyway throughout most of its length, passes through the two reversing bevel pinions and is keyed to pinion can be brought into mesh with a mating bevel gear by means of the reversing lever on the front of the apron and thus provide “forward” or “reverse” power to the clutches connect either the rack pinion or the crossslide screw to provide longitudinal motion of the carriage or transverse motion of cross cutting threads, a second means of longitudinal drive is provided by a lead motion of the carriage when driven by the feedrod mechanism takes place through a friction clutch in which slippage is possible, motion through the lead screw is by a direct, mechanical connection between the apron and the lead is achieved by a split means of a clamping lever on the front of the apron, the split nut can be closed around the lead the split nut closed, the carriage is moved along the lead screw by direct drive without possibility of 14 頁 第 3 頁┊ ┊ ┊ ┊ ┊ ┊ ┊ ┊ ┊ ┊ ┊ ┊ ┊ 裝 ┊ ┊ ┊ ┊ ┊ 訂 ┊ ┊ ┊ ┊ ┊ 線 ┊ ┊ ┊ ┊ ┊ ┊ ┊ ┊ ┊ ┊ ┊ ┊ ┊畢業(yè)設計（論文）報告紙Modern lathes