Design and Assembly of Worm Gear Reducer

Worm gear speed reducers are comprised of the terms “gearbox” and “speed reducer” that are used interchangeably in the world of power transmission and motion control. Gearboxes are used for speed reduction and torque multiplication. A hybrid term of “gear reducer” is also commonly used when talking about gearboxes. This is simply a gearbox (or speed reducer, or gear reducer) with a motor directly mounted to the input. A gearbox designed using a worm and worm-wheel will be considerably smaller than one made from plain spur gears and has its drive axes at 90° to each other. With a single start worm, for each 360° turn of the worm, the worm-gear advances only one tooth of the gear. Therefore, regardless of the worm's size (sensible engineering limits notwithstanding), the gear ratio is the "size of the worm gear - to - 1". Given a single start worm, a 20 tooth worm gear will reduce the speed by the ratio of 20:1. With 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 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 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-D 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 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 the CAD knowledge and sharpen the design skills. Creo Parametric is a very user-friendly design software which was very useful for this purpose. Furthermore, certain manufacturing activities like facing, cutting, milling and drilling activities were also completed on the designed parts. The manufacturing changes were reviewed in Vericut. Thus, to sum it up, designing a worm gear reducer takes a lot of patience and hard work, eventually leading to the potential development of 3-D design attributes.