普通车床加工非标准模数蜗杆的挂轮调整计算
多年来，我们在-车床</A>上加工非标准螺纹时，原则上不制作专用挂轮，而是通过合理组合机床原有挂轮速比，或利用公制、英制、模数、径节螺纹之间的关系，通过调整计算来实现被加工螺距值。在各种型号的-车床</A>中，<FONT face="Times New Roman">C620-1</FONT>车床可实现的螺距值最多，但该车床铭牌上标示的螺距值只是其实际可实现螺距值的一部分。<FONT face="Times New Roman">C620-1</FONT>车床铭牌上标示的公制螺纹螺距值只有<FONT face="Times New Roman">43</FONT>种，而实际可实现螺距值为<FONT face="Times New Roman">72</FONT>种；英制螺纹螺距值铭牌标示为<FONT face="Times New Roman">20</FONT>种，实际可实现螺距值为<FONT face="Times New Roman">72</FONT>种；模数螺纹螺距值铭牌标示为<FONT face="Times New Roman">38</FONT>种，实际可实现螺距值为<FONT face="Times New Roman">72</FONT>种；径节螺纹螺距值铭牌标示<FONT face="Times New Roman">37</FONT>种，实际可实现螺距值为<FONT face="Times New Roman">72</FONT>种。可见，机床铭牌上标示的螺距值总共为<FONT face="Times New Roman">138</FONT>种，而实际可实现螺距值为<FONT face="Times New Roman">288</FONT>种，如能将铭牌上未标示出的螺距值充分利用起来，可挂导程的数量可增加一倍，对于非标准螺纹的加工将带来很大方便。如果用机床原有挂轮无法实现加工，则只需更换一个主动轮或从动轮，非标准螺纹零件的加工计算问题一般都能解决。<BR><BR> 《-机械</A>制造》杂志<FONT face="Times New Roman">1998</FONT>年第<FONT face="Times New Roman">8</FONT>期《巧算挂轮》一文中提出了加工模数为<FONT face="Times New Roman">3</FONT>．<FONT face="Times New Roman">15</FONT>、头数为<FONT face="Times New Roman">2</FONT>的蜗杆的调整计算方法。我们认为：<BR> （<FONT face="Times New Roman">1</FONT>）该方法需重新制作两个-挂轮</A>，即新的传动比为<FONT face="Times New Roman">42</FONT>／<FONT face="Times New Roman">80</FONT>，<FONT face="Times New Roman">42</FONT>齿的挂轮为主动轮，应为<FONT face="Times New Roman">A</FONT>轮；<FONT face="Times New Roman">80</FONT>齿的挂轮为从动轮，应为<FONT face="Times New Roman">C</FONT>轮。但该文说<FONT face="Times New Roman">42</FONT>齿挂轮为<FONT face="Times New Roman">A</FONT>轮，<FONT face="Times New Roman">80</FONT>齿挂轮为<FONT face="Times New Roman">B</FONT>轮，此说欠妥。因<FONT face="Times New Roman">B</FONT>轮是中间轮，对传动比不起作用，参见下图。<P align=center><STRONG><IMG border=0 alt="" src="http://www.chmcw.com/upload/news/article/83/13220_9qdw9j2008-06-03-14-10-43158.gif"></STRONG></P>
<P align=center>图</P>
<P align=left> （<FONT face="Times New Roman">2</FONT>）该文选用<FONT face="Times New Roman">CD6140A</FONT>车床是不适当的，因为模数<FONT face="Times New Roman">3</FONT>．<FONT face="Times New Roman">15</FONT>和模数<FONT face="Times New Roman">6</FONT>．<FONT face="Times New Roman">3</FONT>都是<FONT face="Times New Roman">7</FONT>的倍数，而<FONT face="Times New Roman">CD6140A</FONT>车床挂轮箱内的几个挂轮齿数为<FONT face="Times New Roman">48</FONT>、<FONT face="Times New Roman">72</FONT>、<FONT face="Times New Roman">76</FONT>、<FONT face="Times New Roman">81</FONT>、<FONT face="Times New Roman">96</FONT>，均非<FONT face="Times New Roman">7</FONT>的倍数，因此用<FONT face="Times New Roman">CD6140A</FONT>车床加工模数为<FONT face="Times New Roman">3</FONT>．<FONT face="Times New Roman">15</FONT>的<FONT face="Times New Roman">2</FONT>头蜗杆相当困难，必须重新制作挂轮。本文建议选用<FONT face="Times New Roman">C620-1</FONT>、<FONT face="Times New Roman">C620-3</FONT>、<FONT face="Times New Roman">CA6140</FONT>、<FONT face="Times New Roman">CA6150</FONT>等车床比较合适。<BR> 现以选用<FONT face="Times New Roman">C620-1</FONT>车床为例，提出以下合理计算方法。<BR> 例<FONT face="Times New Roman">1</FONT>．利用模数挂轮速比计算模数为<FONT face="Times New Roman">3</FONT>．<FONT face="Times New Roman">15</FONT>的<FONT face="Times New Roman">2</FONT>头蜗杆的加工导程：<BR> （<FONT face="Times New Roman">1</FONT>）原车床加工模数螺纹的挂轮速比为<FONT face="Times New Roman">32</FONT>／<FONT face="Times New Roman">97</FONT>，可实现车床铭牌标示模数<FONT face="Times New Roman">0</FONT>．<FONT face="Times New Roman">25</FONT>、<FONT face="Times New Roman">0</FONT>．<FONT face="Times New Roman">5</FONT>、<FONT face="Times New Roman">0</FONT>．<FONT face="Times New Roman">75</FONT>、<FONT face="Times New Roman">1</FONT>、<FONT face="Times New Roman">1</FONT>．<FONT face="Times New Roman">5</FONT>、<FONT face="Times New Roman">1</FONT>．<FONT face="Times New Roman">75</FONT>、<FONT face="Times New Roman">2</FONT>、<FONT face="Times New Roman">2</FONT>．<FONT face="Times New Roman">25</FONT>、<FONT face="Times New Roman">3</FONT>、<FONT face="Times New Roman">3</FONT>．<FONT face="Times New Roman">25</FONT>、<FONT face="Times New Roman">3</FONT>．<FONT face="Times New Roman">5</FONT>、<FONT face="Times New Roman">3</FONT>．<FONT face="Times New Roman">75</FONT>、<FONT face="Times New Roman">4</FONT>、<FONT face="Times New Roman">4</FONT>．<FONT face="Times New Roman">5</FONT>、<FONT face="Times New Roman">4</FONT>．<FONT face="Times New Roman">75</FONT>、<FONT face="Times New Roman">5</FONT>、<FONT face="Times New Roman">5</FONT>．<FONT face="Times New Roman">5</FONT>、<FONT face="Times New Roman">6</FONT>、<FONT face="Times New Roman">6</FONT>．<FONT face="Times New Roman">5</FONT>、<FONT face="Times New Roman">7</FONT>、<FONT face="Times New Roman">8</FONT>、<FONT face="Times New Roman">9</FONT>、<FONT face="Times New Roman">20</FONT>……。<BR> （<FONT face="Times New Roman">2</FONT>）原车床的两套挂轮速比<FONT face="Times New Roman">32</FONT>／<FONT face="Times New Roman">97</FONT>和<FONT face="Times New Roman">42</FONT>／<FONT face="Times New Roman">100</FONT>可组合成新的挂轮速比<FONT face="Times New Roman">32</FONT>／<FONT face="Times New Roman">100</FONT>。<BR> （<FONT face="Times New Roman">3</FONT>）计算模数为<FONT face="Times New Roman">6</FONT>．<FONT face="Times New Roman">3</FONT>时的加工导程：<BR> 修正系数＝新的挂轮速比<FONT face="Times New Roman">32</FONT>／<FONT face="Times New Roman">100÷</FONT>原车床模数速比<FONT face="Times New Roman">32</FONT>／<FONT face="Times New Roman">97</FONT>＝<FONT face="Times New Roman">0</FONT>．<FONT face="Times New Roman">97<BR></FONT> 要求加工模数＝铭牌标示模数<FONT face="Times New Roman">6</FONT>．<FONT face="Times New Roman">5×</FONT>修正系数<FONT face="Times New Roman">0</FONT>．<FONT face="Times New Roman">97</FONT>＝<FONT face="Times New Roman">6</FONT>．<FONT face="Times New Roman">305<BR></FONT> 实际计算导程＝<FONT face="Times New Roman">6</FONT>．<FONT face="Times New Roman">305×3</FONT>．<FONT face="Times New Roman">1416</FONT>＝<FONT face="Times New Roman">19</FONT>．<FONT face="Times New Roman">80mm<BR></FONT> 要求加工导程＝<FONT face="Times New Roman">6</FONT>．<FONT face="Times New Roman">3×3</FONT>．<FONT face="Times New Roman">1416</FONT>＝<FONT face="Times New Roman">19</FONT>．<FONT face="Times New Roman">79mm<BR></FONT> 导程误差＝<FONT face="Times New Roman">19</FONT>．<FONT face="Times New Roman">80</FONT>－<FONT face="Times New Roman">19</FONT>．<FONT face="Times New Roman">79</FONT>＝<FONT face="Times New Roman">0</FONT>．<FONT face="Times New Roman">01mm<BR></FONT> 导程误差可以满足加工精度要求。<BR> 例<FONT face="Times New Roman">2</FONT>．利用螺距挂轮速比计算模数为<FONT face="Times New Roman">3</FONT>．<FONT face="Times New Roman">15</FONT>的<FONT face="Times New Roman">2</FONT>头蜗杆的加工导程：<BR> （<FONT face="Times New Roman">1</FONT>）原车床加工螺杆的螺距速比为<FONT face="Times New Roman">42</FONT>／<FONT face="Times New Roman">100</FONT>，可实现铭牌标示的螺距为<FONT face="Times New Roman">1</FONT>、<FONT face="Times New Roman">2</FONT>、<FONT face="Times New Roman">3</FONT>、<FONT face="Times New Roman">4</FONT>、<FONT face="Times New Roman">5</FONT>、<FONT face="Times New Roman">6</FONT>、<FONT face="Times New Roman">7</FONT>、<FONT face="Times New Roman">8</FONT>、<FONT face="Times New Roman">9</FONT>、<FONT face="Times New Roman">10</FONT>、<FONT face="Times New Roman">11</FONT>、<FONT face="Times New Roman">12</FONT>、<FONT face="Times New Roman">13</FONT>、<FONT face="Times New Roman">14</FONT>、<FONT face="Times New Roman">16</FONT>、<FONT face="Times New Roman">18</FONT>、<FONT face="Times New Roman">19</FONT>、<FONT face="Times New Roman">20</FONT>、<FONT face="Times New Roman">22</FONT>、<FONT face="Times New Roman">24</FONT>、<FONT face="Times New Roman">26</FONT>……。<BR> （<FONT face="Times New Roman">2</FONT>）原车床的两挂轮速比<FONT face="Times New Roman">32</FONT>／<FONT face="Times New Roman">97</FONT>和<FONT face="Times New Roman">42</FONT>／<FONT face="Times New Roman">100</FONT>可组合成新的挂轮速比<FONT face="Times New Roman">32</FONT>／<FONT face="Times New Roman">100</FONT>。<BR> （<FONT face="Times New Roman">3</FONT>）计算模数为<FONT face="Times New Roman">6</FONT>．<FONT face="Times New Roman">3</FONT>时的加工导程：<BR> 修正系数＝新的挂轮速比<FONT face="Times New Roman">32</FONT>／<FONT face="Times New Roman">100÷</FONT>原车床螺距速比<FONT face="Times New Roman">42</FONT>／<FONT face="Times New Roman">100</FONT>＝<FONT face="Times New Roman">0</FONT>．<FONT face="Times New Roman">7619<BR></FONT> 要求加工螺距＝铭牌标示螺距<FONT face="Times New Roman">26×</FONT>修正系数<FONT face="Times New Roman">0</FONT>．<FONT face="Times New Roman">7619</FONT>＝<FONT face="Times New Roman">19</FONT>．<FONT face="Times New Roman">80mm<BR></FONT> 要求加工导程＝<FONT face="Times New Roman">6</FONT>．<FONT face="Times New Roman">3×3</FONT>．<FONT face="Times New Roman">1416</FONT>＝<FONT face="Times New Roman">19</FONT>．<FONT face="Times New Roman">79mm<BR></FONT> 导程误差＝<FONT face="Times New Roman">19</FONT>．<FONT face="Times New Roman">80</FONT>－<FONT face="Times New Roman">19</FONT>．<FONT face="Times New Roman">79</FONT>＝<FONT face="Times New Roman">0</FONT>．<FONT face="Times New Roman">01mm<BR></FONT> 导程误差可以满足加工精度要求。</P>
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