Patent ID: 7296473

Claim:
A pressure sensor comprising: an airtight case equipped with first and second pressure input orifices provided respectively on opposing first and second wall surfaces; a cylindrical first bellows fixed on the first wall surface at one end and equipped with a shaft hole communicating with the first pressure input orifice; a cylindrical second bellows fixed on the second wall surface at one end, equipped with a shaft hole communicating with the second pressure input orifice, and arranged in series with the first bellows; a resonator-adhering pedestal arranged and fixed between other ends of the first and second bellows; a lamellar piezoelectric resonator supported by the resonator-adhering pedestal; and an oscillation circuit electrically connected to an electrode pattern of the piezoelectric resonator, wherein: the piezoelectric resonator is fixed on the second wall surface at one end and fixed on the resonator-adhering pedestal at the other end; a piezoelectric reinforcement plate is fixed between the second wall surface and the resonator-adhering pedestal at a position across the second bellows from the piezoelectric resonator; and an inner wall of the airtight case is joined to the resonator-adhering pedestal by a resilient reinforcement member.