Do gearboxes need oil cooling?

The primary purpose of the lubricating oil in a gearbox is:

• To Lubricate
• To remove heat
• To remove the debris that has got generated because of mechanical gears meshing together and working.

If the temperature of the oil is high, it will not be able to remove the heat that is getting generate. Plus, as the temperature rises, the viscosity of the oil drops and it’s ability to lubricate properly is reduced. A drop in viscosity also reduces the buoyant force of the fluid. This in turn reduces its ability to carry away debris.

Most large continuous duty gearboxes do need an external oil cooling system or mechanism. In some cases, we can get it by attaching a fan to the drive motor to enhance the natural heat dissipation but in most large continuous duty applications we do need to have an external oil cooling mechanism in place. The oil is sucked in from the sump of the gearbox, passed through an air cooled heat exchangers or water cooled oil cooler and back to the sump usually through the top of the gearbox.