A pressure transducer comprises a housing including a body section and at least one end cap at one end of the body section, which are made of piezoelectric crystal, and a piezoelectric resonator in the housing. The body section and the end cap are bonded by an atomic diffusion bonding method.

A combustion pressure detection device for detecting combustion pressure inside a combustion chamber of an internal combustion engine, the combustion pressure detection device being attachable to a communication hole communicating an inside of a cylinder head configuring the combustion chamber and an outside thereof, the combustion pressure detection device includes: a housing; and an piezoelectric element and the like that are located in the housing and detect the combustion pressure. The housing has an attachment structural part attachable to the communication hole, the attachment structural part has a third outer peripheral surface to which a first seal member is attachable, and a inclined surface to which a second seal member is attachable, and the inclined surface is arranged at a front end side in a direction to the combustion chamber relative to the third outer peripheral surface when the combustion pressure detection device is attached to the communication hole.

A combustion pressure detection device for detecting combustion pressure inside a combustion chamber of an internal combustion engine, the combustion pressure detection device being attachable to a communication hole communicating an inside of a cylinder head configuring the combustion chamber and an outside thereof, the combustion pressure detection device includes: a housing; and an piezoelectric element and the like that are located in the housing and detect the combustion pressure. The housing has an attachment structural part attachable to the communication hole, the attachment structural part has a third outer peripheral surface to which a first seal member is attachable, and a inclined surface to which a second seal member is attachable, and the inclined surface is arranged at a front end side in a direction to the combustion chamber relative to the third outer peripheral surface when the combustion pressure detection device is attached to the communication hole.

A pressure sensor outputting an electrical signal upon a fluid pressure in a target space includes a diaphragm having a pressure receiving surface disposed in the target space for receiving a fluid pressure, and a back surface on a back side of the pressure receiving surface, an inner member disposed to face the back surface and a diaphragm supporting portion connected to the diaphragm. The diaphragm includes a center portion disposed to face the inner member and is distorted as a concave shape toward the detecting direction because of the heat transmitted to the pressure receiving surface and the distortion of the center portion as a concave shape toward the detecting direction. A contacting portion provided on a connecting portion between the center portion and the outside portion is in contact with the inner member.

A pressure sensor includes a tubular housing; a diaphragm which is joined to one end portion of the housing through a fusion zone; and a sensor element which is disposed in the housing and to which pressure received by the diaphragm is transmitted. As viewed in a section which contains the center axis of the housing, a pair of the fusion zones exist, and each of the fusion zones is formed in such an inclined manner that its distance from the center axis increases as it extends from the outer surface of the diaphragm toward the other-end-portion side of the housing.

A method and a system for transmitting a sensor signal, transmits the sensor signal in such a way that the analog electrical sensor signal is converted with the aid of a system for signal conversion into a converted signal and that this converted signal is transmitted to a control unit. As a result, the sensor signal is able to be transmitted to the control unit in a reliable manner and be evaluated thereby.

A method and a system for transmitting a sensor signal, transmits the sensor signal in such a way that the analog electrical sensor signal is converted with the aid of a system for signal conversion into a converted signal and that this converted signal is transmitted to a control unit. As a result, the sensor signal is able to be transmitted to the control unit in a reliable manner and be evaluated thereby.

A strain sensor is provided which includes a strain sensor, a first housing, a second housing joined to the first housing, and a pressure measuring mechanism firmly retained between the first housing and the second housing. The pressure measuring mechanism is gripped between a first face of the first housing and a second face of the second housing to measure compressive stress exerted by a cylinder head of an internal combustion engine on the first housing and the second housing. This structure improves the reliability of mechanical strength of the housings and the pressure measuring mechanism and provides flexibility in selecting the type of the pressure measuring mechanism.

A strain sensor is provided which includes a strain sensor, a first housing, a second housing joined to the first housing, and a pressure measuring mechanism firmly retained between the first housing and the second housing. The pressure measuring mechanism is gripped between a first face of the first housing and a second face of the second housing to measure compressive stress exerted by a cylinder head of an internal combustion engine on the first housing and the second housing. This structure improves the reliability of mechanical strength of the housings and the pressure measuring mechanism and provides flexibility in selecting the type of the pressure measuring mechanism.

The present invention is a pressure sensor (1) which includes a sensor main body (2) having a cavity, a cantilever (3) having a lever main body (20) and a lever support portion (21A, 21B) and which is bent according to a pressure difference between the cavity and the outside of the sensor main body (2), and a displacement detection unit (4) which detects displacement of the cantilever (3) based on resistance variation in resistance values of the main body-resistance portion (31) formed in the lever main body (20) and a lever-resistance portion (32) formed in the lever support portion (21A, 21B). A division groove (40) is formed in the lever support (21A), and the division groove (40) divides the lever-resistance portion (32) into a first resistance portion (32a) which is electrically connected to a detection electrode (35) in series and a second resistance portion (32b) which is positioned so as to be closer to the other adjacent lever support portion (21B) than the first resistance portion (32a). The first resistance portion (32a) of the lever support portion (21A, 21B) is electrically connected to the detection electrode (35) via a parallel path of a first path (S1) passing through the main body-resistance portion (31) and a second path (S2) passing through the second resistance portion (32b).