Main parameters and common issues of hydraulic pumps
Main parameters
The main parameters of a hydraulic pump include pressure, speed, displacement and flow rate, power and efficiency, etc.
(1) Pressure
① The actual output pressure of a hydraulic pump during operation is called the working pressure. During the operation of hydraulic pumps, the working pressure of the pump varies with the load (pressure adaptation), that is, the larger the load, the higher the working pressure of the pump, and vice versa, the working pressure of the pump is smaller; Or it can be stabilized at one or several set values by a pressure control valve or constant pressure pump (single-stage pressure regulation or multi-stage pressure regulation); For a proportional control pressure system, the pump pressure will vary with the input signal (current) of the proportional pressure control valve.
② The rated pressure Pn is the maximum pressure that can be continuously operated under normal working conditions according to the test standards, which is called the rated pressure of the hydraulic pump. The rated pressure is also known as the nominal pressure. The rated pressure of a hydraulic pump is limited by factors such as the structural strength and leakage of the pump itself, and exceeding this value is considered overload.
③ The maximum allowable pressure pmax, according to the test standards, is the maximum pressure that exceeds the rated pressure and allows for brief operation, which is called the maximum allowable pressure of the hydraulic pump (referred to as the maximum pressure).
④ The pressure difference between the discharge port pressure and the suction port pressure of a hydraulic pump is called the pressure difference of the hydraulic pump. Usually, the inlet pressure of a pump is very low, approximately zero, so in many cases, the outlet working pressure p of the pump can be used as a substitute.
The legal unit of measurement for hydraulic systems and component pressure (working pressure, rated pressure, maximum pressure, etc.) in China is Pa (Pa, N/m2). When the pressure is high, MPa (megapascal) is used to express it (1MPa=106 Pa). The pressure should comply with the pressure series specified in GB/T 2346-2003
