| 摘要 |
PURPOSE:To detect with high accuracy without obstructing the flow of a fluid flow rate by forcing a vibrating piece provided inside the fluid flowing route to vibrate and by detecting the reduced quantity of the amplitude in case of the amplitude being reduced according to the increase in the flow rate. CONSTITUTION:A vibrating piece 2 is provided in parallel to the air flow inside a sucking air tube 1 passed into the cylinder of an engine for instance. The vibrating piece 2 provides an electrode 2d in its center, a piezoelectric vibrator 2e on its one face and displacement measuring piezoelectric body 2f on the other face, and electrodes are arranged with vapor deposition respectively to the vibrator 2e, the piezoelectric body 2f. The vibrating piece 2 is connected respectively to an excitation circuit 91, receiving circuit 92. The vibrating piece 2 is then forced to be vibrated with the output from the excitation circuit 91 and when the fluid flow is many, the vibrating piece 2 receives a force from both sides and the amplitude is reduced and the alternating voltage to receive 92 from the displacement measuring piezoelectric body 2f is reduced. The fluid flow rate is then calculated from the receiving signal with an arithmetic circuit 93. Since the flow rate is detected with the amplitude of a vibrating piece, therefore, the detection is enabled with a simple device. |
