ELECTROHYDRAULIC VIBRATION EXCITED BY 2D VALVE

Abstract

The frequency bandwidth of the electrohydraulic vibrator conventionally constructed by a servo valve and a hydraulic cylinder or a motor is to a large extent limited to fairly narrow range by the dynamic response capability of the servo valve. A 2D electrohydraulic valve is thus developed to enhance the working frequency range to a new high level. In this 2D valve, the continuous rotary motion of the spool is used to create alternated variation of the valve port areas, while the linear motion of the spool is to control the peak value of the valve port areas. The frequency excited by 2D valve is proportional to the rotary speed of the spool and thus the high-frequency can easily be achieved by increasing the rotary speed of the spool well lubricated in hydraulic oil. Experiments have been carried out to the vibrator loaded by an elastic force coming from the deformation of a frame work and the wave forms of the cylinder piston was measured. It is demonstrated that the ascent and descent slopes of the wave form show some inconsistency which alleviates with the reduction of valve linear opening. The phenomenon is explained to be caused by the changing direction of the elastic force. Nevertheless, the wave from is close to a sinusoidal one. It is concluded the development of the 2D valve does point out an access to the high-frequency excitation of the hydraulic vibration.