The hydraulic main pump is a kind of fluid pump. About the fluid sealing, it usually uses the mechanical seal to contain the fluid within a vessel (typically pumps, mixers, etc.) where a rotating shaft passes through a stationary housing or occasionally, where the housing rotates around the shaft.

Mechanical seals are usually fixed at the point of entry or exit of a rotating shaft. Typically it is used to prevent the leakage of one high-pressure fluid into a lower pressure fluid.

And to maintain the power of the hydraulic main pump.

Typically, the skeleton oil seal in the free state, the diameter is smaller than the shaft diameter, that is, a certain amount of interference.

Therefore, when the oil seals after loading the oil seal seat and the shaft oil seal edge of the pressure and force of contraction of the coil spring from the tight on the shaft a certain radial tightening force, the pressure decreases rapidly after a period of time to run and even disappear, and thus, together with the spring can always compensate for oil seal from the tightening force. .

Sealing principle: oil seal edge to control the oil film between the oil seal and the shaft, this film has a fluid lubriion characteristic.