What is a hydraulic pump?
Through this page, I tried to make a short description about hydraulic pump although the subject is well known. If you google it you will find some good information about it.
Even though the subject is widely know I will show more in-depth information from source, where I learned and understand this hydraulic component.
I will present here the axial piston pump because I know this type of pump. I serviced this kind of pump on board, bench tested and assembled in the workshop. From practical side I am familiar with this type of hydraulic pump.
I will start with basic explanation of what is a hydraulic pump and the role of it in a hydraulic system.
Characteristic of a pump is to convert mechanical energy into hydraulic energy.
A hydraulic device is a device that is use to convey energy (in the form of force) by means of liquid.
To cause a cylinder to extend and retract and to make a motor work it needs a flow of oil. A pump delivers the flow of oil. The volume of oil delivered by pump is not the only important factor to cause a cylinder or a motor to perform a designated work. The force of the pump, which delivers the oil plays and important role.
To overcome a resistance (load) it needs a force to exert to oil flow when encounters resistance. The force represent pressure so pump deliver pressure when the oil flow experiences resistance (load). Pressure exists because of resistance.
Other important aspect for a hydraulic pump is an adequate oil supply to the suction or inlet side. If the pump is unable to draw in enough oil will result a vacuum with formation of a phenomenon called cavitation. For more information about cavitation, follow the link.
A dirty inlet filter can cause vacuum on the inlet side of the pump and cavitation occur. The type of filters to be used are usually stated by the pump manufactured. The maintenance factor is very important, when the filter element has to be renewed use the same type or a similar one.
Pressure or outlet side of pump must always be able to release the oil at a lower pressure than the maximum permissible pump pressure. Thus, a pressure limiting valve must always be installed.