| Worm gears are used for reducing speeds and | | | | extreme pressure (EP) mineral oils, polyalphaolefin |
| increasing torque. They are quite compact and can | | | | (PAO) lubricants, and polyalkylene glycols (PAG). |
| achieve very high speed ratios, often 60:1 or higher. | | | | Compounded, mineral-based oils have natural or |
| Unfortunately, due to the way they operate, they | | | | synthetic fatty additives that provide good lubricity and |
| produce a lot of heat and require special lubrication. | | | | better protection against sliding wear. These oils are |
| This article will help you understand the basics of | | | | made from a mineral basestock, containing rust and |
| worm gear lubrication. | | | | oxidation inhibitors, and blended with acidless tallow and |
| Worm gears and worms contact each other through | | | | fatty additives. |
| sliding rather than rolling. This increases friction and thus | | | | Mineral-based, extreme pressure gear oils are often |
| the operating temperature. Worm gears may operate | | | | used when no brass components are present. Brass |
| at close to twice the temperature of other similar gear | | | | components may react with the sulfur-phosphorous |
| configurations such as spur gears. | | | | additives found in these oils, although the latest EP oils |
| Due to the sliding motion, the worm slowly rubs off the | | | | utilize non-active sulfur to reduce possible corrosion. EP |
| lubricant film while engaging with the worm wheel. The | | | | oils are often used for steel gears and when shock |
| worm surface picks up more lubricant after | | | | loading occurs. PAO gear lubricants have good lubricity |
| disengaging, but it is difficult to ensure that it will have a | | | | properties to help prevent sliding wear. The additives |
| lubricant film that is thick enough to last through the | | | | should be checked to make sure that the oil is |
| load zone. As a result, worm drives require high | | | | compatible with the gear material(s). |
| viscosity lubricants (due to the high operating | | | | PAG lubricants are rather new but are becoming more |
| temperatures) and have good lubricity to overcome | | | | common. They have excellent lubricity, a very high |
| the high-load metal-to-metal contact. | | | | viscosity and are a great choice for low or high |
| There are four types of lubricants that are commonly | | | | temperature operation. Please note that they are not |
| used with worm gears: compounded mineral oils, | | | | compatible with some mineral oils, seals, and paints. |