Abstract: A pressure sensor including a housing extending along an axial line, a diaphragm fixed to a front-end side of the housing, a piezoelectric unit disposed in a hole in the housing and including a piezoelectric element, a transmission member that transmits deformation of the diaphragm to the piezoelectric unit, and a guide member having a through hole extending along the axial line and surrounding the piezoelectric unit in the through hole. (SL/AL)?0.26 is satisfied in the cross section perpendicular to the axial line passing through the piezoelectric element, where SL is the maximum value of the distance in the radial direction between the center of the through hole and the center of the piezoelectric element and AL is the maximum value of the distance in the radial direction between the outside surface of the piezoelectric element and the center of the through hole.

Abstract: A pressure sensor including: a cylindrical casing extending in an axial direction; a diaphragm joined to the distal end side of the casing, extending in a direction intersecting the axis of the casing and deforming in accordance with pressure received on the distal end side; and a sensor section disposed inside the casing and outputting an electric signal corresponding to the deformation of the diaphragm. The diaphragm is provided with a plate-shaped base part and three or more protruding parts protruding from the distal end side surface of the base part toward the distal end side and set apart from each other. The relationships 0.05?H?2.5T and 0.05?(S2/S1)?0.8 are satisfied, where T (thickness), H (length), S1 (area of base distal end surface) and S2 (total area of protruding distal end surfaces) are as defined herein.

Abstract: A pressure sensor including: a cylindrical casing extending in an axial direction; a diaphragm joined to the distal end side of the casing, extending in a direction intersecting the axis of the casing and deforming in accordance with pressure received on the distal end side; and a sensor section disposed inside the casing and outputting an electric signal corresponding to the deformation of the diaphragm. The diaphragm is provided with a plate-shaped base part and three or more protruding parts protruding from the distal end side surface of the base part toward the distal end side and set apart from each other. The relationships 0.05?H?2.5T and 0.05?(S2/S1)?0.8 are satisfied, where T (thickness), H (length), S1 (area of base distal end surface) and S2 (total area of protruding distal end surfaces) are as defined herein.

Abstract: A pressure sensor includes: a diaphragm joined to a front side of a housing via a joint portion; a sensor portion; a connection portion connecting the diaphragm to the sensor portion; and a heat receiving portion disposed at the front side of the diaphragm. When: a minimum value of an area of a minimum inclusion region which is a virtual region, which include a cross-section of a portion from the heat receiving portion to the diaphragm and of which an overall length of a contour become minimum on a cross-section perpendicular to the axial line, is defined as a connection area Sn; and an area of a region surrounded by the joint portion on a projection plane perpendicular to the axial line when the diaphragm and the heat receiving portion are projected onto the projection plane is defined as a diaphragm effective area Sd, (Sn/Sd)?0.25 is satisfied.

Abstract: A pressure sensor including a housing extending along an axial line, a diaphragm fixed to a front-end side of the housing, a piezoelectric unit disposed in a hole in the housing and including a piezoelectric element, a transmission member that transmits deformation of the diaphragm to the piezoelectric unit, and a guide member having a through hole extending along the axial line and surrounding the piezoelectric unit in the through hole. (SL/AL)?0.26 is satisfied in the cross section perpendicular to the axial line passing through the piezoelectric element, where SL is the maximum value of the distance in the radial direction between the center of the through hole and the center of the piezoelectric element and AL is the maximum value of the distance in the radial direction between the outside surface of the piezoelectric element and the center of the through hole.

Abstract: A pressure sensor includes: a diaphragm joined to a front side of a housing via a joint portion; a sensor portion; a connection portion connecting the diaphragm to the sensor portion; and a heat receiving portion disposed at the front side of the diaphragm. When: a minimum value of an area of a minimum inclusion region which is a virtual region, which include a cross-section of a portion from the heat receiving portion to the diaphragm and of which an overall length of a contour become minimum on a cross-section perpendicular to the axial line, is defined as a connection area Sn; and an area of a region surrounded by the joint portion on a projection plane perpendicular to the axial line when the diaphragm and the heat receiving portion are projected onto the projection plane is defined as a diaphragm effective area Sd, (Sn/Sd)?0.25 is satisfied.

Abstract: 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.

Abstract: A method of manufacturing a pressure sensor including a tubular housing having a lid-shaped support plate formed at one end of the housing, a diaphragm, a piezoelectric element for outputting an electrical signal corresponding to pressure received by the diaphragm, and a rod-shaped transmission section for transmitting the pressure to the piezoelectric element. The method includes the steps of accommodating the piezoelectric element into the housing, and fixing the transmission section to the housing through the diaphragm in a state in which a predetermined preload is applied to the piezoelectric element in an axial direction of the housing by pressing the piezoelectric element against the support plate by the transmission section.

Abstract: 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.