Fabrication and Evaluation of Hydraulic Particle Excitation Valve Vibrated Perpendicularly to Direction of Flow Path

We introduce a new particle excitation control valve driven by the vibration from a direction different than that of the previous particle excitation control valve. Conventional small hydraulic servo valves have a few disadvantages, such as a complex structure and waste of hydraulic energy. To solve these disadvantages, a small hydraulic control valve using a piezoelectric vibrator was studied. We confirm that the proposed control valve was operated with a low viscosity fluid in our previous research. However, the control valve was not operated with a high viscosity fluid as the force required to open the valve increases owing to increase in the viscosity. In this paper, a new prototype valve driven by the vibration perpendicular to the direction of flow was fabricated to achieve valve operation with a common hydraulic oil, and the characteristics of the valve due to a change in the valve seat shapes were also evaluated. As a result, we found the optimum value of the taper angle of the valve seat. When the taper angle of the valve seat is 100°, the prototype valve can be opened by a lesser voltage than the other taper angles. In addition, when the silicone oil was used as the working fluid with a kinematic viscosity of 30 mm2/s, approximately equal to the kinematic viscosity of the common hydraulic oil, we succeeded in opening the valve at 0.8 MPa. Because the previous particle excitation valve could not be opened in a high viscosity working fluid, the present results indicate a possibility for operating the proposed valve with the common hydraulic oil.