TM90502 excavator hydraulic pump proportional solenoid valve

Load sensing and pressure compensation technology of electro-hydraulic proportional multiway valve

In order to save energy, reduce oil temperature and improve control accuracy, and also make several executive elements of synchronous action do not interfere with each other when moving, more advanced construction machinery now uses load sensing and pressure compensation technology. Load sensing and pressure compensation are a very similar concept, both use the pressure change caused by the load change to adjust the pressure and flow of the pump or valve to adapt to the working needs of the system. Load sensing for the quantitative pump system is to lead the load pressure through the load sensing oil circuit to the relief valve of remote pressure regulation. When the load is small, the relief valve setting pressure is also small. The load is large, the setting pressure is also large, but there is always a certain overflow loss. For the variable pump system, the load sensing oil circuit is introduced into the variable mechanism of the pump, so that the output pressure of the pump increases with the increase of the load pressure (always a small fixed pressure difference), so that the output flow of the pump is equal to the actual flow of the system, without overflow loss, and energy saving is realized.

Pressure compensation is a guarantee measure to improve the control performance of the valve. The load pressure after the valve port is introduced into the pressure compensation valve, and the pressure compensation valve adjusts the pressure in front of the valve port so that the pressure difference before and after the valve port is constant, so that the flow through the valve port according to the flow regulation characteristics of the throttle port is only related to the opening of the valve port, and is not affected by the load pressure.