Research On An Adjustable Hydraulic Filter Based On Structure-fluid Coupled Vibration

The vibration and noise which spread over hydraulic system were caused by flow pulsation in Hydraulic system, seriously influence working performance, and reduce system reliability. In the hydraulic system, installing hydraulic filter is one of the most widely used ways which reduce pressure pulsation and noise. Due to the advantages of simple structure and low loss, resonance hydraulic filter has been widely applied in the control of hydraulic filter.As resonance hydraulic filter has strong selectivity and the filter attenuation near the resonance frequency is sharp, it attenuates on deviating from the resonant frequency. In order to make filter get wider attenuation band, we propose an adjustable hydraulic filter based on structure-fluid coupled vibration, which combined frequency attenuation with the second harmonic frequency analyzed by pressure pulsation characteristics of hydraulic system. By concentrating parameter model estimated filter resonant frequency, the paper summarizes methods and designs principles in resonant hydraulic filter. Because the filter comprises of two single-resonant hydraulic filters, we can adjust the main structure parameters and make resonance frequency of single-resonant hydraulic filter differentiate from each other and achieve the relatively wider attenuation band,thus realizing filter frequency tunableness. Based on the acoustic theory, the second harmonic frequency attenuator can be equivalent to a single-degree-of-freedom harmonic excitation force vibration system which has a certain quality and flexibility and damping, so that we can establish a transfer matrix with concentrated parameter four-terminal network flow method. We study the effect of the change of main structure parameters of resonant filter to resonant frequency by numerical methods.The results showed: the change of volume parameters of two resonant chambers and the neck area of the second harmonic frequency can realize the change of resonant frequency which makes the resonance frequency of the change of the filter resonant frequency adapted the frequency changing hydraulic system. When the filter frequency equals or closes to the hydraulic system, weak hydraulic system pulses. When the frequencies of Second harmonic frequency attenuation closes or equals to the second harmonic frequencies of hydraulic filter which can weak hydraulic system pulse, so filter have broad-spectral-bandwidth attenuation in a large quantity. Research results provide a good job for follow-up work.