摘    要

所谓数字控制机床是按照含有机床(刀具)运动信息程序所指定的顺序自动执行操作的过程。而计算机数控机床就是数控机床在计算机监控下进行工作。它的优点很多,可以在同一机床上一次装夹可完成多个操作，生产率显著提高等优点，但它的价格昂贵。由于我国现在使用的机床大多数为普通车床，自动化程度低,要更新现有机床需要很多资金。为了解决这个问题,也为了适应多品种中、小批量零件加工我们选择机床经济型数控改造。纵向进给机构的改造：拆去原机床的溜板箱、光杠与丝杠以及安装座,配上滚珠丝杠及相应的安装装置，纵向驱动的步进电机及减速箱安装在车床的床尾,不占据丝杠空间。横向进给机构的改造：拆除横向丝杠换上滚珠丝杠,由步进电机带动。总体设计方案:CA6140车床主轴转速部分保留圆机床的手动变速功能。车床的纵向和横向进给运动采用步进电机驱动。最后,根据已知条件对纵向横向伺服进给机构进行设计与计算。
                                                                      
关键词:数控、车床、改造

ABSTRACT

 Numerical Control (NC) is any machining process in which the operations are executed automaticallu in sequences as specified by the program that contains the information for the tool movement .When Numerical Control is performed under computer supervision, it is called Computer Numerical Control (CNC).CNC machines have many advantages over conventional machines. For example, there is a possibility lf performing operations on the same machine in one setup and production is significantly increased. One of its disadvantages is that they are quite expensive. In our country conventional machine is used widely. So if the machines are replaced, there is going to need a large money. In order to agree with the development of our economy, we can reform the conventional machines. The reformation of the vertical mechanism: we demolish the current smooth leading, leading screw and installing stand. Then replace the ball leaking to the relevant position. The reformation of the horizontal mechanism: we make the horizontal ball lead screw instead of the conventional screw. And Stepper motor drives the screw. The overall master design: the spindle’s gearshift of the CA6140 mechanism controlled by the former operating lever. The moving of the vertical table and the horizontal table is drove by the ball screw, which is drove by the Stepper motors. The last, we design the vertical and horizontal mechanism on the basis of known numbers.
Key word: Numerical Control、 machining、   information  

目    录

第一章   绪论 1
1.1机床数控改造的意义 3
1.2数控机床的主要改造步骤 3
第二章 设计的任务及要求 5
2.1 CA6140横向进给系统及刀架数控改造设计的任务 5
2.2 CA6140横向进给系统及刀架数控改造设计的要求 5
第三章  改造设计的总体方案 6
3.1设计参数的确定 6
3.2改造方案的确定 7
3.2.1系统的运动方式与伺服系统的选择 7
3.2.2机械传动方式 7
第四章 滚珠丝杠副的设计和计算 8
4.1选择脉冲当量 8
4.2计算切削力 8
4.2.1纵车外圆 8
4.2.2横切端面 8
4.3滚珠丝杆螺母副的计算和选型 9
4.3.1滚珠丝杠轴向进给切削力的计算 9
4.3.2滚珠丝杠的平均转速计算 9
4.3.3滚珠丝杠的寿命计算 10
4.3.4滚珠丝杠副在高速和定工作载荷的情况下的选用 10
4.3.5滚珠丝刚副在受动载荷的情况下的选用 12
4.3.6按额定静载荷选用滚珠丝杠副 13
4.3.7滚珠丝杠副的选型 13
4.3.8滚珠丝杠副的刚度验算 16
       4.3.9滚珠丝杠副的稳定性验算 18
第五章  减速器的设计计算 19
第六章 步进电机的选型及计算 21
6.1等效转动惯量的计算 21