When using an oil pressure gauge to test the performance of hydraulic pumps and motors, the range of the oil pressure gauge used should be 10MPa higher than the rated pressure of the measured hydraulic pump and motor to prevent damage to the oil pressure gauge caused by impact pressure during testing. When testing, the oil pressure gauge should be installed on the inlet and outlet ports and drain ports of the hydraulic pump and hydraulic motor. If there is no pressure measuring joint at the drain port, a transition joint can be made and a pressure measuring joint can be installed on the transition joint.
The power source of hydraulic pumps in construction machinery is mostly diesel engines or electric motors, and the load of hydraulic motors is mostly working devices or walking devices. The power source should be able to be cut off at any time, and the load should be able to change from an unloaded state to a peak state.
During testing, first install the oil pressure gauge on the inlet, outlet, and drain ports of the hydraulic pump and hydraulic motor. Then, start the power source and use a tachometer to measure the approximate time it takes for the main shaft of the hydraulic pump and hydraulic motor to rotate one revolution. Then, measure the time required for the hydraulic pump and hydraulic motor to rotate five or ten revolutions, and calculate the accurate time for the main shaft to rotate one revolution.
The pressure and pointer swing indicated on the oil pressure gauge, as well as the pressure difference between the peaks and valleys, should be observed for each rotation of the hydraulic pump and hydraulic motor. If the pressure values indicated on the hydraulic pump, hydraulic motor inlet and outlet oil pressure gauges do not reach the rated pressure, and the pressure at the drain port exceeds the back pressure pressure of the hydraulic system, it indicates severe wear of the hydraulic pump, motor distribution plate or cylinder body. If there is a large pressure difference between the peaks and valleys of the hydraulic pump and hydraulic motor, it indicates that the distribution plate is worn and skewed, the inclined plate is worn and grooved, or the inclined plate roller bearing is damaged. If the speed of the hydraulic motor rapidly decreases and the pressure at the outlet of the hydraulic pump increases slowly when the load changes, faults such as hydraulic pump variable mechanism jamming, excessive oil flow resistance in the load transmission pipeline of the variable mechanism, and blocked damping holes may occur.
When the pointer of the oil pressure gauge suddenly jumps, observe whether there is a change in the load of the hydraulic pump and hydraulic motor, and also observe whether the sudden jump is regular. If the load of the hydraulic motor does not change and the oil pressure gauge jumps regularly, it may be due to the hydraulic pump or hydraulic motor plunger breaking, cylinder body breaking, or sliding shoe falling off.
2025 November 2rd Week VAFEM Product Recommendation
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2025-11-11