The Working Principle Of Hydraulic Pumps And Motors

There are many types of hydraulic pumps and motors, but they can be divided into two categories based on whether the volume of oil discharged per revolution can be adjusted: quantitative and variable. According to the different structural forms of sealing volume, they can be divided into three categories: gear type, blade type, and plunger type.

When the eccentric wheel is driven to rotate, the plunger moves up and down in the plunger hole of the pump body under the action of the eccentric wheel and spring. When the plunger moves down, the volume of the sealed working oil chamber composed of the plunger hole and the upper end of the plunger increases, forming a vacuum. At this time, the oil discharge valve seals the oil outlet, and the hydraulic oil in the oil tank enters the working oil chamber through the oil inlet valve under atmospheric pressure. This process is the oil inlet process of the plunger pump; When the plunger moves upwards, the volume of the sealed working oil chamber decreases and the pressure increases. At this time, the oil inlet valve seals the oil inlet, and the pressure oil opens the oil discharge valve to enter the system. This process is that if the eccentric wheel continues to rotate, the plunger pump continuously enters and discharges oil.

From the above, it can be seen that the necessary conditions for forming a positive displacement hydraulic pump are: having several well sealed working chambers; There is a power source that continuously increases the volume of the working chamber from small to large, and then decreases from large to small, to complete the process of oil inlet and outlet; There is a suitable oil distribution relationship, that is, the inlet and outlet ports cannot be opened simultaneously.

In principle, hydraulic pumps and hydraulic motors are reversible, but due to different purposes of use, there are certain differences in their structure. Generally, hydraulic pumps and hydraulic motors cannot be interchanged.