A small three-way valve using particle excitation driven by a single piezoelectric transducer for hydraulic actuator

[Display omitted] •We propose a small three-way valve using a piezoelectric vibrator.•The three-way valve is composed of a single piezoelectric vibrator, which enables downsizing compared to conventional.•The fabricated three-way valve can switch the valve to be opened and closed by changing the drive frequency.•Cylinder drive speed can be changed with the manufactured three-way valve. In this study, a small flow valve for controlling hydraulic actuators was developed. Recently, robot actuators have been used at sites where humans cannot enter, e.g., disaster sites. However, the control system of a multi-degree-of-freedom mechanism requires many control components, consequently increasing the size of the system, which can be a problem. This paper describes the fabrication and evaluation of a small three-way valve particle excitation valve driven by a single piezoelectric transducer. The three-way valve comprises one transducer and two control valves. Because the two valves have different resonant frequencies, the inlet and outlet ports can be switched by applying different driving frequency voltages to the transducer. Further, changing the voltage applied to the transducer regulates the flow rate. The vibration characteristics of a fabricated three-way valve were evaluated. The resonance frequencies at the inlet and outlet ports were 110 kHz and 168 kHz, respectively, and the vibration speed increased with an increase in the applied voltage, indicating that the three-way valve can switch the opening port by changing the driving frequency as well as control the flow rate. Furthermore, we successfully drove an actuator with the fabricated small three-way valve.