There are many kinds of materials used in vent cap for gearbox, such as aluminum, stainless steel, copper or plastic. According to the actual use, there are common, long pipe, pressure or needle valve type oil cup.

Why should the gearbox be equipped with vent cap?

Because there are a lot of heat when the gearbox works in a high temperature environment or it works for a long time. The gearbox inside temperature can reach about 80 ℃, and some of the heat will be transmitted to the lubricating oil and some will be transmitted to the air for heat dissipation. When the lubricating oil and air are heated, the internal pressure will increase, which will exert an external force on the oil seal, resulting in the failure of the oil seal. Then the gearbox will be oil leakage or the oil will be inflow motor. Because of the oil leakage, the gearbox inside can not be lubricated, resulting in bearing dry working, which seriously affects the gearbox life. Therefore, it is necessary to install a vent cap on the horizontal position of gearbox to balance the internal and external air pressure and avoid the failure of the oil seal.

However, under different conditions, different installation and different types of vent caps, there are different requirements for the gearbox. Sometimes, the incorrect installation method or the wrong selected vent cap type, the vent cap will spray.