To provide a rotator built-in type pressure sensor capable of directly measuring the pressure in the rotator, without requiring a battery or a circuit.
A bulkhead 2, for dividing an internal space of the rotator 4 into at least two or more portions, is provided inside the rotator 4, filled with fluid, and a channel body 23 having a main channel 25 and a bypass channel 24 is provided on the bulkhead 2. In the bypass channel 24, a surface acoustic wave type acceleration sensor 21, comprising a surface acoustic wave resonator 31 formed on the main surface of a cantilever structure 33, is installed, and at least one or more vortex generators 26 are installed on the furthermore positive-pressure side than on the cantilever structure 33. The cantilever structure 33 is vibrated forcibly by Karman vortex 43 generated on the back of the vortex generators 26, and periodic change in the impedance of the surface acoustic wave resonator 31 tat changes in synchronism with the frequency of forced vibration is measured, to thereby detect the pressure difference inside the rotator 4 during the movement of the rotator 4.
TOGANO YUICHI
FUJIWARA CHIEKO
