If you have ever bought a gear and found that it has broken, you know how difficult it can be to get a replacement. A broken gear may require you to create a new drawing and re-use the original one. Unfortunately, this task can be daunting without the right technical knowledge. Insufficient information about gear construction can make it difficult for a gear constructor to provide accurate recommendations. But, it is still possible with the right information and a little bit of effort.
Unlike worm gears, bevel gears use angular gear teeth to transmit force. This means that several teeth are in contact at once, allowing for more torque to be transmitted. Additionally, bevel gears are much quieter than worm gears of the same size, which is a great benefit in quiet environments. Because they have tooth-like surfaces, bevel gears can be used with hollow shafts. This makes them more efficient in applications where noise is an issue.
A worm gear provides additional advantages over a standard gear set. Proper lubrication and proper setup can make a worm gear as effective as any other gear set. In this article, Ray Thibault explores the differences between the two types and explains why they differ. In the end, worm gears are a reliable and effective piece of equipment. Don’t forget to read his article on lubrication for worm gears to learn more about how they work.
Worm gears are particularly susceptible to corrosion if they have brass wheels. When the brass wheel is exposed to sulfur-phosphorous gear oils, the oil will activate and degrade the load surface. Because of this, worm gears need a thick film of lubrication. However, there are a few caveats to consider when choosing gear oils. Here are some important things to consider:
Worm gears offer high reduction ratios and a compact design. Worm gears are similar to machine screws, with their teeth meshing with those of the worm wheel. Worm gears come in single-enveloping and multi-threaded designs. Precision ground stainless steel worm and wheel assemblies will give you the highest accuracy and smoothest operation. Worm gears are also more expensive than standard gears and require frequent lubrication.
Worm gears are also more complex, and require special attention to the center location. In addition to the diameter of the shaft, the worm must also be in line with the circular pitch of the larger gear. Worms made from bronze are more prone to catching in the teeth, so work-hardening is necessary. A worm gear’s tooth profile is measured using the same inspection equipment as a helical gear. This measurement can indicate any deviation from the straight line. Worm teeth can also be measured by measuring over pins or using a gear tooth caliper.
Worm gears are difficult to inspect because they can suffer from excessive wear due to the worm’s movement. Worms can have different diameters, which makes determining tooth thickness difficult. Worm gears are also often difficult to measure with pins, balls, and gear tooth calipers. A more indirect way to check tooth thickness is by measuring backlash. Backlash can vary significantly and if it is not consistent, it could be a sign that tooth spacing is not perfect.