Dynamics Simulation And Experiment On Hydraulic Motor Pump's Rotor

Hydraulic motor pump is a new type of highly integrated hydraulic power unit. It is not only clean and environmental, but also has the complex dynamics' problems of the internal coupling between the multi-systems. With the double swash plate motor pump as the prototype for research, the issue obtains the calculation model of the radial hydraulic force according to analyzing the changing pressure in one piston chamber. The radial friction can be gotten through studying the sliding friction between the piston shoe and the swash plate. The gap permeability in the uneven gap between the stator and the rotor must be analyzed to research unbalanced magnetic pull during the rotor vibrating. “Machine-Electric-Fluid” coupling dynamic model of rigid rotor is established on the basis of the above forces interaction.Based on the dynamic model explained above, the paper studies the rotor's dynamic response supported by cylindrical roller and sliding bearing to compare the effect on vibration response. The vibration amplitude and the main vibration frequency of the rotor under different synchronous speed motor are analyzed to compare the vibration effect of the unbalanced magnetic pull. The characteristics of the vibration of the rotor under different piston number are also studied to find the influence of the odd and even number of piston on the rotor's vibration displacement.The rotor dynamics model of hydraulic motor pump is applicable and can actually response the rotor's vibration mode, which has been tested by experiment. Experimental results of amplitude spectrum analysis shows that the rotor 's vibration frequency is mainly distributed in the low frequency region, indicating the view is correct, that the rotor can be regarded as a rigid body. At the low load, the displacement tracks of the center of the rotor indicate that the unbalanced magnetic force and the centrifugal force play a major role in the vibration of the rotor. Under the rated load, observing from the direction of the fluid pressure, the results of experiment and the theoretical analysis is opposite, the main reason is that the bearing has the clearance actually, and that the radial hydraulic pressure eliminate the bearing clearance, counteract the effect caused by centrifugal force, and increase the bearing's stiffness and damping. Besides, the model also has the shortage of ignoring the rolling bearing's clearance.