数控自动回转刀架及其控制系统设计毕业论文

毕业设计
题目自动回转刀架及其控制系统设计专业数控加工与维护工程
班级
学生
指导教师
西安工业大学函授部
二0 0 九年
摘要
数控转刀架是数控车床的一个重要功能部件,它以回转分度方式实现切削工具的自动转换。

目前已有多种类型产品形成专业化生产,其中双插销反靠式数控转塔刀架是国内研制的一种电动机械刀架。

其结构简单,成本低廉,已在国内各类数控车床中有广泛应用，但故障率较高。

数控(NC)刀架是数控机床的重要部件,加工工件的质量有有相当程度取决于NC刀架的性能。

它以回转分度实现刀具自动交换及回转动力刀具的传动。

因技术含量高,已经趋向专业化开发生产。

所以对数控转塔刀架的研究开发及应用己引起数控机床行业的重视。

本设计是蜗轮蜗杆传动与定位装置的刀架,用来使装夹于刀架板上的许多刀具之一进入操作位置。

本设计涉及采用电力机就操作之高速车床所用刀架。

在对大量工件进行机械加工时,需要按照预定的和自动控制的周期对同一工件顺序的使用若干刀具。

此外,机械加工中的一项基本要求就是速度,是要减少从一种刀具加工完毕至下一种刀具开始加工之间,转台使新的刀具转至相应操作位置的全部动作所需的空载时间
关键词：数控刀架自动回转工件
目录
第一章数控的发展及其刀架
1.1. 国内发展情况 ·····························································································1.
2. 国外发展情况 ·····························································································1.
3. 结构组成与动作循环····················································································1.
4. 技术性能与发展趋势····················································································1.4.1. 精度·······································································································1.4.2. 运转性能·································································································1.4.3. 润滑与密封······························································································1.4.4. 负载能力与刚度························································································1.4.5 可靠性方面 ······························································································1.5 现代典型数控转塔刀架的结构分析···································································1.
5.1. 液压式····································································································1.5.2. 液压机械式······························································································1.5.3. 电动势····································································································1.6 控制与接口 ·······························································································1.
6.1 直接与数控系统接口 ··················································································1.6.2 通过可编程序控制器(PLC)与数控系统接口······················································1.7 各种刀架简介······························································································1.
7.1 简易经济型数控刀架 ··················································································1.7.3 带动力刀具的数控刀架 ···············································································第二章方案选择及论证
2.1 传动方案的分析和拟定··················································································2.1.1 技术关键 ·································································································2.1.2 数控立式四工位抬起式自动刀架传动方案的分析和拟定 ·····································第三章主要参数的计算
3.1 刀架的设计参数···························································································3.2 动力参数的确定···························································································3.2.1 选择电机类型··························································································3.2.2 电机容量的设计计算 ···············································································
第四章传动机构的设计计算
蜗杆传动的设计计算··························································································4.1.1 选择蜗杆传动类型 ·····················································································4.1.2 选择材料 ·································································································4.1.3 按齿面接触疲劳强度设计 ············································································4.1.4 蜗轮蜗杆的主要参数及尺寸 ·········································································4.1.5 校核齿根弯曲疲劳强度 ···············································································4.1.6 精度等级和表面粗糙度的确定 ······································································4.1.7 蜗轮蜗杆的结构 ························································································4.1.8 蜗杆传动的热平衡计算 ···············································································4.2 丝杆螺母传动的设计计算···············································································4.2.1 丝杆材料的选择 ························································································4.2.2 螺母材料的选择 ························································································4.2.3 丝杆螺母几何尺寸的计算 ············································································4.3 定位机构的设计···························································································4.3.1 插销的设计计算 ························································································4.3.2 预定位机构与反靠机构 ···············································································4.3.3 精定位机构多齿盘的设计 ············································································4.3.4 弹簧的设计计算 ························································································．蜗杆轴的校核 ································································································5.1 基本硬件组成······························································································第五章刀架的接口与控制
5.2 通过可编程序控制器（PLC）与控制系统实现接口··············································5.3 可编程序控制器（PLC）控制程序设计 ·····························································5.3.1 输入点分配 ······························································································5.3.2 输出点 ····································································································结束语
致谢
参考文献
第一章数控的发展及其刀架
1.1. 国内发展情况
我国的刀架生产还出在发展阶段，品种、规格、可靠性等方面还需要有一个完善的过程，远远没有达到成熟。

基本上采用传统材料和传统，加上部分外购配套件的可靠性较差造成产品整体的可靠性与外国的差距。

国内部分刀架回转原理为电机经弹簧理合器带动蜗杆，再由蜗轮带动蜗杆旋转，当刀架转体时，由霍尔元件不断检测刀架转体是否到位，到位后霍尔元件发出信号，然后反转锁紧。

主要采用有销盘、内齿盘，外齿盘组成的三端齿定位机构实现准确定位。

其控制部分主要选用MCS-51系列单片机以及ATMEL公司的AT89等同类产品进行控制。

烟台机床附件厂是目前我国生产刀架水平最高的厂家，特别是可以生产带刀头的刀架。

该厂家全套引进意大利的生产线，产品属于高档型。

1.2. 国外发展情况
国外数控机床附件产品的开发应用比较早，经验丰富，再由于技术进步，新材料，新结构的不断出现与应用，使得其产品的可靠性比较高。

国外主要分为日本和欧美两大流派。

其产品的特点是夹紧力大，采用专用电机，体积小，转矩大，可靠性高，耐磨，可靠性较高。

比如，日本日研公司部分回转刀架的核心部件蜗杆副，蜗轮采用氮化钢，齿部表面采用氮化处理，硬度高；蜗杆为硬质合金蜗杆；整个蜗杆副为硬齿面接触，耐磨。

既实现了高速又保证了高可靠性。

还有德国的肖特（SAUTER）、意大利的杜普洛马蒂克（DUPLOMATIC）和巴鲁法迪（BARUFFALDI）等，他们都有自己的系列、规格和专利。

像肖特（SAUTER）的刀架，采用行星传动机构，其结构紧凑，传动方向均为同一方向，没有像蜗杆副的降速机构的交叉轴设计，易于一体化布置。

采用牙嵌式齿行离合器的升起和加紧，空行程转角、小效率高，且自锁功能可靠。

其控制部分大都与机床一起采用CNC控制，目前国际比较好的系统有西门子，法拉克，三菱等。

1.3. 结构组成与动作循环
典型的数控转塔刀架一般有动力源（电极或油缸，液压马达）、机械传动机构、预分度机构、定位机构、锁紧机构、检测装置、接口电路、刀具安装台（刀盘）、动力刀座等组成。

数控转塔刀架的动作循环为：
T指令（换刀指令）→刀盘放松（抬起）→转位→刀位检测→预分度→精确定位→刀具锁紧→结束，答复信号。

1.4. 技术性能与发展趋势
数控转塔刀架的技术发展很快，现正逐步形成标准定型产品。

我国数控转塔刀架标准草案中所规定的主要技术性能如下：
1.4.1. 精度
—mm。

各种形位公差为定位精度要求高，一般要求工位目标位置重复定位精度在4"10"
0.020.03mm -。

因此定位机构均采用精密多齿盘。

先进工艺用浮硬齿面对研,重复定位精度可高达"1另外,刀盘加工趋向用淬火硬磨削,以获得刀槽精度的长期保持性及高的刚度。

1.4.
2. 运转性能
主要是转位时间和转位频率。

先进水平一次转位周期0.3—ls,最快己达。

分度频率为600—1000次/h 。

双向转位就近换刀(最短路程换刀)的结构正在开发应用,如双向滚子端面凸轮机构 , 可显著缩短换到周期。

为了克服刀盘高速转位引起的惯性冲击,使用恰当的缓冲元件是其发展趋势。

1.4.3. 润滑与密封
目前趋向于开发能终生润滑的产品,即在使用全过程中,不需要用户再采取任何润滑措施。

因工作环境恶劣,对密封性能要求很高,通常规定在刀架体内棋道压力105pa 气路 ,浸入装有防锈液的试验箱内,在规定时间内,不得有漏气现象。

1.4.4. 负载能力与刚度
数控转塔刀架的负载能力与刚度,除了与有关零件的尺寸、形状、结构等有关外 , 受刀盘锁紧力影响也很大。

一般小型产品锁紧力为310N 左右,高性能产品可达 4610N ⨯ 以上。

对数控转塔刀架的静刚度目前尚无规范要求,有的企业标准已经提出测详见定, 但缺乏数据指示。

对动刚度,动态性能,在生产实践中反映出其影响明显,但也无可靠数据指示提出,这些方面是今后研究开发中的重要方向。

1.4.5 可靠性方面
可靠性是产品性能的综合反映。

对转塔刀架目前一般要求平均无故障时间(MTBF)为 4510N ⨯次,高级的已经达到4210N ⨯次以上,国内产品在设方面亟待提高。

1.5 现代典型数控转塔刀架的结构分析
1.5.1. 液压式
这类刀架用液压缸实现刀盘锁紧,低速大扭矩液压马达驱动刀盘转位。

液压缸可获得很大的 锁紧力,故刀架刚性很好。

该机构适用于重负荷切削,且易双向转位就近换刀,大型数控车床应用较多。

近年已开发出将液压马达和滚珠式预分度机构合为一体的液压分度马达(Index Motor) 。

可使刀架简化,重复定位精度可达"
0.1±。

刀盘加速时间仅为0.1S,有较好的应用前景。

1.5.
2. 液压机械式
这类刀架用液压缸锁紧刀盘,转位和预分度则用点电机通过机械传动装置实现, 如槽轮机构。

目前趋向采用动态性能较好的间歇凸轮转位机构。

1.5.3. 电动势。