The worm gear and worm reducer has a high reduction ratio and often uses steel-copper friction pairs. The meshing mode is mainly sliding friction, and the tooth surface temperature is prone to rise. The working environment temperature range is wide. Considering the above conditions, the worm gear and worm reducer has higher requirements for lubrication:
1. The appropriate viscosity grade of lubricating oil should be selected. Generally, for medium and small-sized worm gear and worm gear reducers, oil with viscosity grade ISO VG 320 can be used; for large-sized ones, oil with viscosity grades ISO VG 460 or 680 can be chosen. Additionally, according to the starting requirements in low-temperature environments, the viscosity grade can be appropriately reduced or low-temperature lubricating grease can be selected.
2. The lubricating oil is required to possess high anti-wear, extreme-pressure and anti-slip wear resistance properties, and to provide sufficient oil film strength to meet the lubrication requirements for sliding friction.
3. The lubricating oil is required to have good copper corrosion resistance, and the selected additives should have good compatibility with copper materials. Sulfur-containing extreme pressure agents used for ordinary gears usually have strong corrosive effects on copper, and are not suitable for steel-copper friction pairs in worm gear and worm reducer.
4. The lubricating oil is required to have excellent performance in both high and low temperatures. Due to the characteristic that the tooth surfaces of the worm gear and worm reducer tend to heat up easily, the lubricating oil must have excellent viscosity-temperature properties and good thermal conductivity, which can effectively lower the system temperature. When using the reducer in a low-temperature environment, the pour point of the lubricating oil should be low so as to have good low-temperature fluidity, or an appropriate low-temperature lubricating grease should be selected.
5. The lubricating oil is required to have excellent oxidation resistance and a long service life, meeting the lifelong lubrication requirements for small and medium-sized worm gear and worm reducer machines, and the long oil change cycle for large-sized worm gear and worm reducer machines.
In addition to the above requirements, the lubricating oil is also required to possess excellent properties such as good anti-foaming, anti-emulsification, and rubber compatibility.
Therefore, based on the working conditions and lubrication requirements of the worm gear reducer, a special worm gear lubricating oil needs to be selected. Ordinary gear oil cannot meet the specific requirements of the worm gear reducer, such as the anti-sliding friction property, the wear resistance of the copper-steel friction pair, and the corrosion resistance of the copper material.