The Lathe / 车床

The lathe is one of the most useful and versatile machines in the workshop, and is capable of carrying out a wide variety of machining operations.
车床是车间里最有用、最通用的机床之一。它能进行多种机械加工作业。
The main components of the lathe are the headstock and tailstock at opposite ends of a bed, and a tool-post between them which holds the cutting tool. The tool-post stands on a cross-slide which enables it to move sidewards across the saddle or carriage as well as along it, depending on the kind of job it is doing.
车床的主要部件是主轴箱、尾座和刀架。主轴箱与尾座位于床身的两端;用于夹持刀具的刀架置于主轴箱与尾座之间。刀架安装在中拖板上,根据加工的种类,中拖板使刀架既能作横向运动,又能与床鞍一起作纵向运动。
The ordinary center lathe can accommodate only one tool at a time on the tool-post, but a turret lathe is capable of holding five or more tools on the revolving turret. The lathe bed must be very solid to prevent the machine from bending or twisting under stress.
普通顶尖车床在刀架上一次只能安装一把刀具,而在转塔车床的转塔刀架上可同时夹持五把或更多的刀具。车床床身必须非常坚固,以防在应力作用下产生弯曲或扭转变形。

The headstock incorporates the driving and gear mechanism, and a spindle which holds the workpiece and causes it to rotate at a speed which depends largely on the diameter of the workpiece. A bar of large diameter should naturally rotate more slowly than a very thin bar, the cutting speed of the tool is what matters.
主轴箱内有驱动装置与齿轮机构,以及夹持工件并使其旋转的主轴。工件转速很大程度上取决于工件的直径。直径大的棒料自然应比直径很小的棒料转得慢,这与刀具切割速度有很大关系。
Tapered centers in the hollow nose of the spindle and of the tailstock hold the work firmly between them. A feed-shaft from the headstock drives the tool-post along the saddle, either forwards or backwards, at a fixed and uniform speed. This enables the operator to make accurate cuts and to give the work a good finish.
装在空心主轴和尾座轴前端的带锥度的顶尖,把工件牢固地夹在它们之间。由主轴箱带动的光杠驱动刀架,以固定且均匀的速度与床鞍一起来回运动。这使操作者能精确地切削,且使工件得到良好的表面光洁度。
Gears between the spindle and the feed-shaft control the speed of rotation of the shaft, and therefore the forward or backward movement of the tool-post. The gear which the operator will select depends on the type of metal which he is cutting and the amount of metal he has to cut off. For a deep or roughing cut the forward movement of the tool should be less than for a finishing cut.
主轴和光杠之间的齿轮控制着光杠的转速,因而控制了刀架的进退。操作员根据所切金属的种类和要切除的量来选配齿轮。深切或粗切时的走刀速度应比精切时的低。

Centers are not suitable for every job on the lathe. The operator can replace them by various types of chucks, which hold the work between jaws, or by a front-plate, depending on the shape of the work and the particular cutting operation. He will use a chuck, for example, to hold a short piece of work, or work for drilling, boring or screw-cutting.
车床顶尖并非对每种工件都适用。根据工件的形状和特定的切削操作,操作者可用以卡爪夹持工件的卡盘或用花盘来取代顶尖。例如,操作者可以用一个卡盘夹持一个短工件,或需要钻孔、镗孔及车螺纹的工件。
A transverse movement of the tool-post across the saddle enables the tool to cut across the face of the workpiece and give it a flat surface. For screw-cutting, the operator engages the lead-screw, a long screwed shaft which runs along in front of the bed and which rotates with the spindle. The lead-screw drives the tool-post forwards along the carriage at the correct speed, and this ensures that the threads on the screw are of exactly the right pitch.
刀架在床鞍上的横向运动,使刀具能够横切工件的端面使其成为平面。为了车螺纹,操作者接通丝杠(位于床身前面并随着主轴转动的长螺旋轴),丝杠驱动刀架与床鞍一起以准确的速度前进,以保证螺纹螺距的准确性。
The operator can select different gear speeds, and this will alter the ratio of spindle and lead-screw speeds and therefore alter the pitch of the threads. A reversing lever on the headstock enables him to reverse the movement of the carriage and so bring the tool back to its original position.
操作者可选择不同的齿轮速度,而这会改变主轴和丝杠的速比,因而改变了螺纹的螺距。主轴箱上的反向手柄使操作者能改变床鞍的运动方向,因而带着刀具回到初始位置。

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