The Effect Of The Variable Load On The Pressure Of The Hydraulic Cylinder In The Metering-out Control System

Used the metering-out control system in which the hydraulic cylinder was the executive element as research object in this thesis, the experimental research about the effect on the pressure P1, P2 of the hydraulic cylinder chambers when series-connecting throttle valve or governor valve on the return oil-line under the step load changing have made.Accorded to the experimental research, under different flow area of flow valve and different adjusted pressure of relief valve, conclusion that the regulation of the pressure P1,P2 in the two cylinder chambers varied with the change of step load were as follows:When the throttle valve was series-connected on the return oil-line in the metering-out control system, under the same flow area and the same adjusted pressure of relief valve, with the incremental quantity of step load, the pressure highly-adjusted capacity of the hydraulic cylinder chamber with piston-rod decreased, meanwhile, it's time of rise, time to peak and the governing time all decreased. While the pressure highly-adjusted capacity of the hydraulic cylinder chamber without piston-rod increased.When the governing valve was series-connected on the return oil-line in the metering-out control system, under the same flow area and the same adjusted pressure of relief valve, with the incremental quantity of step load, the pressure highly-adjusted capacity of the hydraulic cylinder chamber with piston-rod increased, meanwhile, it's time of rise, time to peak and the governing time all increased. At the same time, the pressure highly-adjusted capacity of the hydraulic cylinder chamber without piston-rod increased.Through experimental research, the calculation formula that the pressure highly-adjusted capacity of two cylinder chambers Varied with the change of step load and the formula about hydraulic elements main parameter (rated pressure) were both made, Which had important valuation in selecting the main parameter about this hydraulic system.This thesis also have constructed mathematic model based on the analytic method, Which used the load as input and the pressure as output, Meanwhile, It have made theoretic analysis of time response. The theoretic analysis was highly agreed with the experimental result.