Volume : 4, Issue : 4, April - 2015

DESIGN AND ASSEMBLY OF WORM GEAR REDUCER

Sobhan Patnaik

Abstract :

<p><p>&lt;p&gt;&amp;nbsp;Worm gear speed reducers are comprised of the terms &amp;ldquo;gearbox&amp;rdquo; and &amp;ldquo;speed reducer&amp;rdquo; that are used interchangeably in&amp;nbsp;&lt;/p&gt; &lt;div&gt;the world of power transmission and motion control. Gearboxes are used for speed reduction and torque multiplication.&amp;nbsp;&lt;/div&gt; &lt;div&gt;A hyid term of &amp;ldquo;gear reducer&amp;rdquo; is also commonly used when talking about gearboxes. This is simply a gearbox (or speed&amp;nbsp;&lt;/div&gt; &lt;div&gt;reducer, or gear reducer) with a motor directly mounted to the input. A gearbox designed using a worm and worm&amp;ndash;wheel will be considerably&amp;nbsp;&lt;/div&gt; &lt;div&gt;smaller than one made from plain spur gears and has its drive axes at 90&amp;deg; to each other. With a single start worm, for each 360&amp;deg; turn of the worm,&amp;nbsp;&lt;/div&gt; &lt;div&gt;the worm&amp;ndash;gear advances only one tooth of the gear. Therefore, regardless of the worms size (sensible engineering limits notwithstanding), the&amp;nbsp;&lt;/div&gt; &lt;div&gt;gear ratio is the &amp;quot;size of the worm gear &amp;ndash; to &amp;ndash; 1&amp;quot;. Given a single start worm, a 20 tooth worm gear will reduce the speed by the ratio of 20:1. With&amp;nbsp;&lt;/div&gt; &lt;div&gt;spur gears, a gear of 12 teeth (the smallest size permissible, if designed to good engineering practices) would have to be matched with a 240&amp;nbsp;&lt;/div&gt; &lt;div&gt;tooth gear to achieve the same ratio of 20:1. Therefore, if the diametrical pitch of each gear was the same, then, in terms of the physical size&amp;nbsp;&lt;/div&gt; &lt;div&gt;of the 240 tooth gear to that of the 20 tooth gear, the worm arrangement is considerably smaller in volume. This paper talks about the 3&amp;ndash;D&amp;nbsp;&lt;/div&gt; &lt;div&gt;design and assembly of a worm gear reducer using the design software tool from PTC, Creo Parametric 2.0. This CAD tool was instrumental in&amp;nbsp;&lt;/div&gt; &lt;div&gt;designing the 20 individual parts and hence creating the assembly of the gear reducer as a w hole. This project was aimed to test and optimize&amp;nbsp;&lt;/div&gt; &lt;div&gt;the CAD knowledge and sharpen the design skills. Creo Parametric is a very user&amp;ndash;friendly design software which was very useful for this purpose.&amp;nbsp;&lt;/div&gt; &lt;div&gt;Furthermore, certain manufacturing activities like facing, cutting, milling and drilling activities were also completed on the designed parts. The&amp;nbsp;&lt;/div&gt; &lt;div&gt;manufacturing changes were reviewed in Vericut. Thus, to sum it up, designing a worm gear reducer takes a lot of patience and hard work,&amp;nbsp;&lt;/div&gt; &lt;div&gt;eventually leading to the potential development of 3&amp;ndash;D design attributes.&lt;/div&gt;</p></p>