Gears are subject to periodically changing contact stress during operation. When the contact stress exceeds the contact fatigue strength of the material, fatigue cracks will occur on the gear surface or subsurface layer. Fatigue cracks continue to expand and extend, eventually causing small pieces of metal to fall off, forming small pits of different shapes. The loss of metal material on the tooth surface and the occurrence of pits are typical characteristics of tooth surface fatigue damage.
1, viscosity
The selection of lubricating oil is closely related to the pitting and pitting corrosion formed on the gear surface, among which the viscosity of the lubricating oil is the key factor. A high load requires a high viscosity lubricant, while a low load requires a lubricating oil with a lower viscosity.
2, speed
Speed also has an effect on pitting corrosion and fatigue of metal contact surfaces. At low speeds, the oil film thickness of the lubricating oil decreases, and similarly at high speeds, the oil film thickness increases. Therefore, when selecting the viscosity of lubricating oil, in addition to considering the load, the speed factor must also be considered.
3, temperature
Temperature factors can also cause pitting corrosion problems. During friction and contact, the temperature increases, the viscosity of the lubricating oil becomes smaller, and the thickness of the oil film decreases. Therefore, if you choose a lubricant with a low viscosity, the oil film becomes too thin and does not provide adequate lubrication protection. Repeated friction will cause pitting corrosion, small pits, and fatigue damage to the metal surface on the surface of the component.
4, accuracy
In addition, installation accuracy will also cause pitting corrosion. Therefore, only by ensuring the installation accuracy, selecting appropriate lubricants, and not changing the rated load of the machine at will can we effectively prevent pitting corrosion.
5, oil detection
It should be noted that the higher the viscosity, the better. Excessive viscosity will also cause the temperature to rise, and high temperature will in turn aggravate the oxidation of the lubricating oil. In this case, if there is no corresponding oil detection, we cannot understand to what extent the oil has been oxidized and whether it has lost its lubricating ability. Therefore, for important occasions, the oil should be tested and the oil should be used according to the conditions of the equipment.
(Source of article: Internet)