I 摘要摘要 车床主要是为了进行车外圆、车端面和镗孔等项工作而设计的机床。车削很少在其他 种类的机床上进行，而且任何一种其他机床都不能像车床那样方便地进行车削加工。由于 车床还可以用来钻孔和铰孔，车床的多功能性可以使工件在一次安装中完成几种加工。因 此，在生产中使用的各种车床比任何其他种类的机床都多。 车床的基本部件有：床身、主轴箱组件、尾座组件、溜板组件、丝杠和光杠。 主轴箱安装在内侧导轨的固定位置上，一般在床身的左端。它提供动力，并可使工件 在各种速度下回转。它基本上由一个安装在精密轴承中的空心主轴和一系列变速齿轮(类 似于卡车变速箱)所组成。通过变速齿轮，主轴可以在许多种转速下旋转。大多数车床有 812 种转速，一般按等比级数排列。而且在现代机床上只需扳动 24 个手柄，就能得到全 部转速。一种正在不断增长的趋势是通过电气的或者机械的装置进行无级变速。 由于机床的精度在很大程度上取决于主轴，因此，主轴的结构尺寸较大，通常安装在 预紧后的重型圆锥滚子轴承或球轴承中。主轴中有一个贯穿全长的通孔，长棒料可以通过 该孔送料。主轴孔的大小是车床的一个重要尺寸，因此当工件必须通过主轴孔供料时，它 确定了能够加工的棒料毛坯的最大尺寸。 关键字关键字：车床；主轴箱组件；主轴；无级变速Abstract Lathes are machine tools designed primarily to do turning, facing and boring, Very little turning is done on other types of machine tools, and none can do it with equal facility. Because lathes also can do drilling and reaming, their versatility permits several operations to be done with a single setup of the work piece. Consequently, more lathes of various types are used in manufacturing than any other machine tool. The essential components of a lathe are the bed, headstock assembly, tailstock assembly, and the leads crew and feed rod. The headstock is mounted in a foxed position on the inner ways, usually at the left end of the bed. It provides a powered means of rotating the word at various speeds . Essentially, it consists 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 speeds. Most lathes provide from 8 to 18 speeds, usually in a geometric ratio, and on modern lathes all the speeds can be obtained merely by moving from two to four levers. An increasing trend is to provide a continuously variable speed range through electrical or mechanical drives. Because 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 types. The spindle has a hole extending through its length, through which long bar stock can be fed. The size of maximum size of bar stock that can be machined when the material must be fed through spindle. Key words: Lathes headstock assembly variable speedIII 目录目录 摘要. I ABSTRACT. II 1 绪论. 1 1.1 毕业设计的目的 . 1 1.2 机床主传动系统设计要求 . 1 2 车床参数的拟定. 2 2.1 车床主参数和基本参数 . 2 2.1.1 极限切削速度 Vmax、Vmin 的确定. 2 2.1.2 主轴的极限转速的确定. 2 2.1.3 主轴转速级数和公比的确定. 3 2.1.4 主电机的选择. 3 3 主传动系统设计. 6 3.1 传动结构式、结构网、转速图的确定 . 6 3.1.1 传动形式的确定. 6 3.1.2 传动组及各传动组中传动副的数目. 6 3.1.3 传动系统扩大顺序的安排 . 7 3.1.4 绘制转速图 . 7 3.1.5 转速图的拟定. 7 3.1.6 分配降速比. 8 3.2 齿轮齿数的确定及传动系统图的绘制 . 10 3.2.1 带轮确定. 10 3.2.2 齿轮齿数的确定的要求. 14 4 强度计算和结构草图设计. 17 4.1 确定计算转速 . 17 4.1.1 各轴、齿轮的计算转速 . 17 4.2 轴的估算和验算 . 19 4.2.1 主轴的设计与计算 . 19 4.2.2 传动轴直径的估算. 22 4.3 齿轮模数的估算和计算 . 24 4.3.1 齿轮模数的估算. 24 4.3.2 齿轮模数的验算 . 264.4 轴承的选择与校核.31 4.4.1 一般传动轴上的轴承选择 .31 4.4.2 主轴轴承的类型 .32 4.4.3 轴承间隙调整和预紧.33 4.4.4 轴承的较核 .34 4.4.5 轴承的密封和润滑.36 4.5 片式摩擦离合器的选择与验算.36 4.5.1 按扭矩选择 .36 4.5.2 片式离合器的计算 .36 4.5.3 计算摩擦面的对数 Z.