数控车床自动转位刀台设计
<STRONG> 1、引言 </STRONG><P><STRONG> </STRONG>目前，铁路列车大幅度提速，要求提速后的车轮单轮不平衡量为70g•m，车轮的幅板、轮毂等以前不加工的回转曲面均需要加工，原有只能加工车轮内外轮辋面、法兰面、踏面的液压仿形机床已不能满足提速后车轮的加工需要。经过对车轮加工工艺路线反复的研究，决定在液压仿形机床基础上进行数控化改造，在原有机床垂直刀架上增加设计一套四工位自动转位刀台，以满足车轮表面全加工的生产需要。车轮的单边余量为8～10mm，经计算本机床主切削力为25kN，考虑到车轮加工中超负荷切削的情况，主切削力定为30kN。目前，国内数控车床中，主切削力为30kN的四工位自动转位刀台尚无现货供应，我厂现有的自动转位刀台主切削力最大为20kN。根据市场需要，决定在现有刀台基础上开发、研制主切削力为30kN的四工位自动转位刀台。该刀台需满足下列要求：（1）定位精度、重复定位精度达到数控立式车床精度标准；（2）刀台刚性好，满足30kN主切削力要求。 </P><P> <STRONG>2、刀台结构</STRONG> </P><P> 本刀台采用多齿盘定位装置，该装置由两个齿数和齿形相同的端面齿盘4、5对合而成，定齿盘5与滑枕8把合在一起，动齿盘4与回转刀台3固连。分度转位时，动齿盘4抬起与定齿盘5脱开，在压力油作用下，活塞齿条10轴向位移，带动轴齿轮9回转一周。轴齿轮9与动齿盘4内齿啮合，带动动齿盘4转过一个工位，然后在碟形弹簧作用下两齿盘4、5重新啮合并压紧，在夹紧油缸压力油作用下，两齿盘4、5得到进一步压紧，大多数齿都紧密接触，可获得很高的定位精度和重复定位精度。最后，活塞齿条10在压力油作用下复位，完成一个自动转位循环。</P><P align=center><IMG height=538 src="http://www.chmcw.com/upload/news/article/83/13220_gmnr5s080923938033330.jpg" width=348 border=0></P><P> 1.碟形弹簧 2.活塞 3.回转刀台 4.动齿盘 5.定齿盘 6、7.定位板 8.滑枕 9.轴齿轮 10.塞齿条 11.缓冲销
多齿盘定位装置有下述特点：（1）分度定位精度高，可达±3，，重复定位精度高，可达±2，。（2）能自动定心。（3）齿面磨损对定位精度影响不大，随着不断使用磨合，定位精度有可能改善，精度保持性好。（4）承载能力强，定位刚性好。本刀台装有粗定位板6、7，在动齿盘4抬起过程中，轴齿轮9与动齿盘4内齿未啮合时，粗定位板6、7先不脱开，在动齿盘4内齿与轴齿轮9啮合后，粗定位板6、7完全脱开。该粗定位板在刀台安装刀夹、刀杆（最大偏载）自由状态下及刀台转位过程中，遇突然停电时，起到防止刀台转过位或转不到位的保护作用。在本刀台自动转位装置中，通过配磨缓冲销11来控制与活塞齿条10之间的0.02～0.03mm液压阻尼间隙，保证刀台转动平稳，在刀台偏载向下旋转过程中，起到防止活塞齿条10与轴齿轮9受冲击影响，磨损较大的现象发生。 </P><P> <STRONG>3、刀台设计计算</STRONG> </P><P> （1）夹紧力的计算 </P><P> 夹紧力W应保证在工作载荷下仍保持齿盘的紧密配合。但夹紧力不应过大，否则会引起齿盘变形而降低定位精度。 </P><P> 正切时夹紧力W计算为：</P><P align=center><IMG src="http://www.chmcw.com/upload/news/article/83/13220_hhqt7a200812112656972.jpg" border=0></P><P align=left> <SPAN style="FONT-SIZE: 10.5pt; COLOR: black; FONT-FAMILY: 宋体; mso-ascii-font-family: Arial; mso-hansi-font-family: Arial; mso-ansi-language: EN-US; mso-fareast-language: ZH-CN; mso-bidi-language: AR-SA; mso-bidi-font-family: Arial">式中</SPAN><SPAN lang=EN-US style="FONT-SIZE: 10.5pt; COLOR: black; FONT-FAMILY: Arial; mso-ansi-language: EN-US; mso-fareast-language: ZH-CN; mso-bidi-language: AR-SA; mso-fareast-font-family: 宋体">S——</SPAN><SPAN style="FONT-SIZE: 10.5pt; COLOR: black; FONT-FAMILY: 宋体; mso-ascii-font-family: Arial; mso-hansi-font-family: Arial; mso-ansi-language: EN-US; mso-fareast-language: ZH-CN; mso-bidi-language: AR-SA; mso-bidi-font-family: Arial">安全系数，一般取</SPAN><SPAN lang=EN-US style="FONT-SIZE: 10.5pt; COLOR: black; FONT-FAMILY: Arial; mso-ansi-language: EN-US; mso-fareast-language: ZH-CN; mso-bidi-language: AR-SA; mso-fareast-font-family: 宋体">S=1</SPAN><SPAN style="FONT-SIZE: 10.5pt; COLOR: black; FONT-FAMILY: 宋体; mso-ascii-font-family: Arial; mso-hansi-font-family: Arial; mso-ansi-language: EN-US; mso-fareast-language: ZH-CN; mso-bidi-language: AR-SA; mso-bidi-font-family: Arial">～</SPAN><SPAN lang=EN-US style="FONT-SIZE: 10.5pt; COLOR: black; FONT-FAMILY: Arial; mso-ansi-language: EN-US; mso-fareast-language: ZH-CN; mso-bidi-language: AR-SA; mso-fareast-font-family: 宋体">1.5</SPAN><SPAN style="FONT-SIZE: 10.5pt; COLOR: black; FONT-FAMILY: 宋体; mso-ascii-font-family: Arial; mso-hansi-font-family: Arial; mso-ansi-language: EN-US; mso-fareast-language: ZH-CN; mso-bidi-language: AR-SA; mso-bidi-font-family: Arial">，若工作条件平稳、冲击负荷小，则</SPAN><SPAN lang=EN-US style="FONT-SIZE: 10.5pt; COLOR: black; FONT-FAMILY: Arial; mso-ansi-language: EN-US; mso-fareast-language: ZH-CN; mso-bidi-language: AR-SA; mso-fareast-font-family: 宋体">S</SPAN><SPAN style="FONT-SIZE: 10.5pt; COLOR: black; FONT-FAMILY: 宋体; mso-ascii-font-family: Arial; mso-hansi-font-family: Arial; mso-ansi-language: EN-US; mso-fareast-language: ZH-CN; mso-bidi-language: AR-SA; mso-bidi-font-family: Arial">取小值（本文取</SPAN><SPAN lang=EN-US style="FONT-SIZE: 10.5pt; COLOR: black; FONT-FAMILY: Arial; mso-ansi-language: EN-US; mso-fareast-language: ZH-CN; mso-bidi-language: AR-SA; mso-fareast-font-family: 宋体">S=1.3</SPAN><SPAN style="FONT-SIZE: 10.5pt; COLOR: black; FONT-FAMILY: 宋体; mso-ascii-font-family: Arial; mso-hansi-font-family: Arial; mso-ansi-language: EN-US; mso-fareast-language: ZH-CN; mso-bidi-language: AR-SA; mso-bidi-font-family: Arial">）</SPAN><SPAN lang=EN-US style="FONT-SIZE: 10.5pt; COLOR: black; FONT-FAMILY: Arial; mso-ansi-language: EN-US; mso-fareast-language: ZH-CN; mso-bidi-language: AR-SA; mso-fareast-font-family: 宋体"> </SPAN></P><P><SPAN lang=EN-US style="FONT-SIZE: 10.5pt; COLOR: black; FONT-FAMILY: Arial; mso-ansi-language: EN-US; mso-fareast-language: ZH-CN; mso-bidi-language: AR-SA; mso-fareast-font-family: 宋体"> Pz——</SPAN><SPAN style="FONT-SIZE: 10.5pt; COLOR: black; FONT-FAMILY: 宋体; mso-ascii-font-family: Arial; mso-hansi-font-family: Arial; mso-ansi-language: EN-US; mso-fareast-language: ZH-CN; mso-bidi-language: AR-SA; mso-bidi-font-family: Arial">切削力（</SPAN><SPAN lang=EN-US style="FONT-SIZE: 10.5pt; COLOR: black; FONT-FAMILY: Arial; mso-ansi-language: EN-US; mso-fareast-language: ZH-CN; mso-bidi-language: AR-SA; mso-fareast-font-family: 宋体">Px=Py=0.5Pz=15000N</SPAN><SPAN style="FONT-SIZE: 10.5pt; COLOR: black; FONT-FAMILY: 宋体; mso-ascii-font-family: Arial; mso-hansi-font-family: Arial; mso-ansi-language: EN-US; mso-fareast-language: ZH-CN; mso-bidi-language: AR-SA; mso-bidi-font-family: Arial">）</SPAN><SPAN lang=EN-US style="FONT-SIZE: 10.5pt; COLOR: black; FONT-FAMILY: Arial; mso-ansi-language: EN-US; mso-fareast-language: ZH-CN; mso-bidi-language: AR-SA; mso-fareast-font-family: 宋体"> </SPAN></P><P><SPAN lang=EN-US style="FONT-SIZE: 10.5pt; COLOR: black; FONT-FAMILY: Arial; mso-ansi-language: EN-US; mso-fareast-language: ZH-CN; mso-bidi-language: AR-SA; mso-fareast-font-family: 宋体"> Mn</SPAN><SPAN style="FONT-SIZE: 10.5pt; COLOR: black; FONT-FAMILY: 宋体; mso-ascii-font-family: Arial; mso-hansi-font-family: Arial; mso-ansi-language: EN-US; mso-fareast-language: ZH-CN; mso-bidi-language: AR-SA; mso-bidi-font-family: Arial">齿盘承受的扭矩（</SPAN><SPAN lang=EN-US style="FONT-SIZE: 10.5pt; COLOR: black; FONT-FAMILY: Arial; mso-ansi-language: EN-US; mso-fareast-language: ZH-CN; mso-bidi-language: AR-SA; mso-fareast-font-family: 宋体">Mn=0.3-Py-0.23Px=1050N·m</SPAN><SPAN style="FONT-SIZE: 10.5pt; COLOR: black; FONT-FAMILY: 宋体; mso-ascii-font-family: Arial; mso-hansi-font-family: Arial; mso-ansi-language: EN-US; mso-fareast-language: ZH-CN; mso-bidi-language: AR-SA; mso-bidi-font-family: Arial">）</SPAN><SPAN lang=EN-US style="FONT-SIZE: 10.5pt; COLOR: black; FONT-FAMILY: Arial; mso-ansi-language: EN-US; mso-fareast-language: ZH-CN; mso-bidi-language: AR-SA; mso-fareast-font-family: 宋体"> </SPAN></P>
页:
[1]