JP2010210544A - Pressure sensor - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To reduce a diameter of a pressure sensor. <P>SOLUTION: The pressure sensor includes: a housing 18 having a pair of concentrically-disposed pressure input ports; and a pair of concentrically-disposed diaphragms 12, 14 for sealing the pressure input ports in the housing 18, and having external surfaces as pressure receiving surfaces. The housing 18 includes a force transmitting means 16 for connecting the pressure receiving surfaces of the diaphragms 12, 14; and a piezoelectric element 22 connected to the force transmitting means at one end, connected to the housing at the other end, and having a detection axis configured so as to be parallel to the pressure receiving surfaces of the diaphragms. Oscillation circuit boards 24, 26 are disposed so as to be parallel to the diaphragms. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a pressure sensor, and more particularly to a pressure sensor that uses a piezoelectric vibration element as a pressure-sensitive element and incorporates a driving substrate thereof.

  Conventionally, a pressure sensor using a piezoelectric vibration element as a pressure-sensitive element is known as a water pressure gauge, a barometer, a differential pressure gauge, or the like. In the piezoelectric vibration element, for example, an electrode pattern is formed on a plate-shaped piezoelectric substrate, and a detection axis is set in the force detection direction. When pressure is applied in the direction of the detection axis, The resonance frequency changes, and the pressure is detected from the change in the resonance frequency.

  As such pressure sensors, those disclosed in Patent Documents 1 and 2 are known. This is because the two bellows are arranged in a straight line in the sensor housing and the pedestal is sandwiched between them, and the pressure fluctuation caused by the difference in pressure introduced to each bellows is caused by the behavior of the pedestal along the expansion and contraction direction of the bellows. It is something to be detected. For this reason, the vibrator bonding pedestal is sandwiched between one end of the first bellows and one end of the second bellows, and on the outer peripheral side of the second bellows, on the other end side of the pedestal and the second bellows. Each of both ends of the pressure sensitive element is fixed to the housing wall surface. And the structure which arrange | positions a reinforcement board in the line symmetrical position which pinches | interposes a 2nd bellows, and fixes each of the both ends of the said reinforcement board to the said base and the said housing wall surface is employ | adopted. Furthermore, an oscillation circuit board that is electrically connected to the electrode pattern on the piezoelectric vibration element is attached to the inner wall of the sensor housing in parallel with the bellows using a gap between the sensor housing and the bellows.

  According to such a pressure sensor, due to the difference between the pressure introduced into the first bellows (for example, atmospheric pressure) and the pressure introduced into the second bellows (for example, the liquid pressure of the detection target liquid). The base between the bellows moves in the bellows expansion / contraction direction, and a tensile force or a compression force acts on the piezoelectric vibration element according to this behavior. Since the resonance frequency generated in the piezoelectric vibrating element by the oscillation circuit changes due to the pressure difference, the pressure can be detected by detecting this change.

JP 2005-121628 A JP 2007-57395 A

  By the way, in the conventional pressure sensor, the oscillation circuit board for driving the pressure-sensitive element is attached to the inner wall surface of the sensor housing in parallel with the bellows using the gap between the sensor housing and the bellows. The housing must have a rectangular cross-sectional shape and a flat surface must be secured inside, and there has been a limit to miniaturization, particularly to reduce the diameter.

  The present invention pays attention to the above-mentioned conventional problems, and particularly aims at reducing the diameter of the pressure sensor. It is another object of the present invention to provide a pressure sensor having a structure suitable for a case where a small diameter pipe is inserted into the ground for measuring the groundwater level and the like and the pressure sensor is accommodated therein.

SUMMARY An advantage of some aspects of the invention is to solve at least a part of the problems described above, and the invention can be implemented as the following application examples.
[Application Example 1] A housing having a pressure input port and a diaphragm having the pressure input port of the housing sealed and having an outer surface as a pressure receiving surface, and bending of the pressure receiving surface of the diaphragm in the housing. And a pressure-sensitive element having one end supported by the force-transmitting means and the other end supported by the housing and having a detection shaft set parallel or coaxial with the pressure-receiving surface of the diaphragm. A pressure sensor comprising: an oscillation circuit board arranged in parallel with the pressure receiving surface of the diaphragm.

  With the above configuration, since the oscillation circuit board is arranged in parallel with the diaphragm, the inner diameter of the housing is only restricted by the diaphragm, and the housing can be reduced in diameter. As a result, for example, when applied to an inspection in which a pressure sensor is arranged inside the excavation pipe for detecting groundwater pressure, the diameter dimension of the excavation pipe can be reduced, thereby reducing the cost for excavation work. Can be achieved.

Application Example 2 A housing having a pair of concentric pressure input ports and a pair of concentric diaphragms that seal the pressure input ports of the housing and have an outer surface as a pressure receiving surface In the housing, force transmitting means for connecting the pressure receiving surfaces of the diaphragms, one end connected to the force transmitting means and the other end connected to the housing, the detection shaft being parallel to the pressure receiving surface of the diaphragm. A pressure sensor comprising a pressure-sensitive element set in (1) and an oscillation circuit board disposed in parallel with the diaphragm.
With the above configuration, a structure having a small-diameter housing as a relative pressure detection sensor can be obtained.

Application Example 3 A housing having a pressure input port and a diaphragm having a pressure receiving surface sealed by sealing the pressure input port of the housing and bending of the pressure receiving surface of the diaphragm in the housing A force transmission means interlocking with the pressure transmission element, and a pressure sensitive element having one end connected to the force transmission means and the other end connected to the housing and having a detection shaft set coaxially with the pressure receiving surface of the diaphragm, An oscillation circuit board is arranged in parallel with the pressure receiving surface of the diaphragm.
With the above configuration, a structure having a thin housing as an absolute pressure detection sensor can be obtained.

Application Example 4 The pressure sensor according to any one of Application Examples 1 to 3, wherein the oscillation circuit board is an oscillation circuit board that drives the pressure-sensitive element.
Thereby, it can be set as the pressure sensor which has a drive circuit.

Application Example 5 The oscillation circuit board includes an oscillation circuit board that drives a resonance signal of the pressure-sensitive element and an oscillation circuit board that drives a temperature sensor for temperature correction of the piezoelectric element. The pressure sensor according to any one of Application Examples 1 to 3, wherein the pressure sensor is arranged as follows.
With the above configuration, the oscillation circuit can be separated for driving the piezoelectric element and for driving the temperature sensor, and the output power can be increased.

Application Example 6 The oscillation circuit substrate is a single-layer substrate in which an oscillation circuit that drives a resonance signal of the pressure-sensitive element and an oscillation circuit that drives a temperature correction temperature sensor of the piezoelectric element are integrally formed. The pressure sensor according to any one of Application Examples 1 to 3, wherein:
By adopting the above configuration, the pressure sensor driving circuit and the temperature sensor driving circuit are mounted on the single circuit board on the oscillation circuit board, so that the structure is advantageous in reducing the height.

Application Example 7 The pressure sensor according to any one of Application Examples 1 to 6, wherein the pressure-sensitive portion of the pressure-sensitive element includes at least one columnar beam.
With this configuration, the movement of the diaphragm can be detected by a compressive force and a tensile force, and highly accurate pressure detection is possible.

1 is a schematic cross-sectional view of a pressure sensor according to a first embodiment of the present invention. It is a schematic cross section of a pressure sensor according to a second embodiment of the present invention. It is sectional drawing of the pressure sensor which concerns on 1st Embodiment of this invention. FIG. 4 is a partial cross-sectional exploded perspective view of FIG. 3. It is sectional drawing of the pressure sensor which concerns on 3rd Embodiment. It is an application example of a pressure sensor applied to groundwater pressure detection.

Hereinafter, specific embodiments of a pressure sensor according to the present invention will be described in detail with reference to the drawings.
1 and 2 are schematic views of first and second embodiments showing a schematic configuration of a pressure sensor according to the present invention. The pressure sensor 10 shown in FIG. 1 is connected by a center shaft (force transmission means) 16 disposed on an axis connecting the central regions of a pair of concentric diaphragms 12 and 14, and the outer peripheral edges of the diaphragms 12 and 14 are connected. Surrounded by the housing 18. As a result, a sealed space 20 surrounded by the diaphragms 12 and 14 is formed in the housing. In the sealed space 20, a piezoelectric element 22, which is a pressure sensitive element, is disposed in parallel with the center shaft 16, one end of which is supported and fixed to a movable portion 19 provided in the middle of the center shaft 16, and the other end is attached to the housing 18. It is supported and fixed to the fixed portion 21 provided, and is arranged so that the detection axis of the piezoelectric element 22 is parallel to the center shaft 16. In the drawing, atmospheric pressure is applied to the upper first diaphragm 12 (18a is an atmospheric pressure inlet), and the lower second diaphragm 14 is set to be applied with the liquid pressure of the detection target liquid. By doing so, the center shaft 16 connected to the diaphragms 12 and 14 moves in the axial direction connecting the central regions of the diaphragms 12 and 14 by the amount corresponding to the differential pressure. When the movable portion 19 moves in the axial direction in conjunction with the movement of the center shaft 16, a compressive force or a tensile force acts on the piezoelectric element 22, and the piezoelectric element is generated by the compressive stress or tensile stress generated inside by this force. The resonance frequency of 22 changes, and the relative pressure can be obtained by detecting the amount of change.

  By the way, such a pressure sensor 10 requires an oscillation circuit for driving the piezoelectric element 22 and an oscillation circuit for driving a temperature sensor for temperature compensation of the pressure sensor 10. In order to attach the oscillation circuit board 24 for piezoelectric elements and the oscillation circuit board 26 for temperature sensors provided with such a circuit to the housing 18, in this embodiment, it has the structure which has arrange | positioned two layers on the 1st diaphragm 12 upper part. . For this reason, the side wall of the housing 18 is raised upward, and the oscillation circuit board is supported in multiple stages so that the housing is parallel to the diaphragms 12 and 14. Accordingly, both the oscillation circuit boards 24 and 26 can be configured as circular boards concentric with at least the diaphragms 12 and 14 while having a flat plate structure. As a result, the inner diameter of the housing 18 is determined by the outer diameter dimensions of the oscillation circuit boards 24 and 26 and the diaphragms 12 and 14, and the outer dimensions can be significantly reduced as compared with the case where the housing 18 is attached to the side wall of the housing. That is, the diameter of the pressure sensor 10 can be reduced.

  The pressure sensor 100 shown in FIG. 2 includes a piezoelectric element oscillation circuit and a temperature sensor oscillation circuit as a single oscillation circuit board 28, and a single upper part of the first diaphragm 12 so as to be parallel to the diaphragm. The oscillation circuit board 28 is supported on the housing 18 side. Others are the same as in the first embodiment. In this case, since the piezoelectric element oscillation circuit and the temperature sensor oscillation circuit are mounted on the same single oscillation circuit board 28, the height can be reduced and the pressure sensor 100 can be made smaller.

  Here, as the configuration of the oscillation circuit, the designer appropriately determines the specifications based on the application and needs and makes an optimal design, and as a result, the number of parts constituting the oscillation circuit also increases or decreases. However, the feature of the present invention is not affected by the number of parts of the oscillation circuit, and the circuit board can be composed of one or more according to the number of parts and the size of each part. These circuit boards can be designed as circular boards concentric with the diaphragms 12 and 14, and can be configured without changing the inner diameter of the housing 18, so that the housing cross section of the pressure sensor 10 can be reduced in diameter. It has been realized.

Next, it demonstrates in detail based on FIGS. 3-4 which show the specific structure of the piezoelectric sensor 10 which concerns on 1st Embodiment.
The pressure sensor 10 has a housing 18 made of a hollow cylindrical body. The housing 18 has a hermetic terminal block 30 as a first member (upper end face plate) and a flange end face plate 32 as a second member (lower end face plate), and is surrounded by a cylindrical side wall 34 as a third member. Is configured as a hollow sealed container. A first pressure input port 36 and a second pressure input port 38 communicating with the internal space of the housing are formed as recessed portions in the outer surface portions of the hermetic terminal block 30 and the flange end plate 32, and the housing is formed on the bottom plate portion. A through hole 40 concentric with the 18 shaft cores is drilled to communicate the inside and outside. The first diaphragm 12 and the second diaphragm 14 are fitted in the recessed portions of the pressure input ports 36 and 38, respectively, and the periphery thereof is integrally connected to the hermetic terminal block 30 and the flange end face plate 32, whereby the inside and outside are connected. To be shielded. The first diaphragm 12 on the side of the hermetic terminal block 30 is for atmospheric pressure reception introduced into the housing from the atmospheric pressure introduction port 52a of the housing, and the second diaphragm 14 of the flange end plate 32 is, for example, the pressure reception pressure of the liquid to be detected. It is for use. The housing 18 is also in a state where the inside and outside are blocked, and the inside can be maintained in a vacuum state by the air venting means 42 shown in FIG.

  Inside the housing 18, a center shaft (force transmission means) 16 that interconnects central regions of the inner surfaces of the first and second diaphragms 12 and 14 is disposed along the axis of the housing 18. Both are bonded and connected through the through hole 40. A movable portion 44 as a pressure-sensitive element cradle is integrally provided in the middle of the center shaft 16, and the first and second diaphragms 12, 14 serve as detection axes with respect to the movable portion 44. One end of a piezoelectric element 22 composed of a double tuning fork vibrator set in parallel with an axis perpendicular to the pressure receiving surface is attached. The other end portion of the piezoelectric element 22 is connected to a boss portion 46 serving as a piezoelectric element receiving base projecting inwardly provided on the hermetic terminal block 30 of the housing 18. As a result, when the center shaft 16 moves in the axial direction due to the differential pressure between the second diaphragm 14 for receiving a pressure to be measured such as a liquid to be detected and the first diaphragm 12 for receiving the atmospheric pressure, the movable portion follows this. 44 changes the position, and this force generates an acting force in the detection axis direction of the piezoelectric element 22.

  As the piezoelectric element constituting the pressure sensitive element, a double tuning fork vibrator having a pressure sensitive part (vibrating part) consisting of two columnar beams is used. A single beam type piezoelectric element may be used.

  Inside the housing 18, a side shaft 48, which is a plurality of guide shafts, is disposed parallel to the center shaft 16 and around the center shaft 16. These hold the gap between the flange end face plate 32 as the second member and the hermetic terminal block 30 as the first member constant, so that the detection accuracy is not lowered due to deformation of the housing 18 due to external force or an arbitrary posture. . Further, the Herme terminal 50 penetrates the Herme terminal block 30 so that the signal of the piezoelectric element 22 is taken out from the sealed space 20 to the outside.

  In addition to the basic structure of the pressure sensor 10, in the first embodiment, as described in FIG. 1, the piezoelectric element oscillation circuit substrate 24 including an oscillation circuit that drives the resonance signal of the piezoelectric element 22, A temperature sensor oscillation circuit board 26 including an oscillation circuit for driving a temperature sensor for temperature compensation of the pressure sensor 10 is arranged on the first diaphragm 12 in two layers. Therefore, the cylindrical side wall 34 of the housing 18 is raised upward to form a substrate housing chamber 52 above the second diaphragm 14, and the oscillation circuit substrate is parallel to the diaphragms 12, 14 in the interior thereof. 24 and 26 are supported in multiple stages. Each of the oscillation circuit boards 24 and 26 is formed as a disk having a slightly smaller diameter than the hermetic terminal block 30 and, as shown in FIG. A screw through hole 58 through which the screw 56 passes is provided. These oscillating circuit boards 24 and 26 are fixed at a concentric position with the pair of side shafts 48, and the fixing screw 56 is screwed into a screw hole 60 formed at a corresponding position of the hermetic terminal block 30. To be fixed. A gap is formed between the piezoelectric element oscillation circuit board 24 and the hermetic terminal block 30, and a spacer 62 is interposed in order to maintain a gap between the oscillation circuit boards 24 and 26.

  The oscillation circuit substrate 24 for piezoelectric elements is mounted with an IC 64, a constant determining capacitor 66, a resistor 68, and the like, and oscillates the piezoelectric element 22 by electrical connection with the Herme terminal 50. Further, the temperature sensor oscillation circuit board 26 is mounted with a temperature sensor element 70 and an IC 72, measures the environmental temperature of the housing, and corrects the temperature of the piezoelectric element by a temperature compensation circuit provided in an external control device (not shown).

  By adopting such a structure of the pressure sensor 10, both the oscillation circuit boards 24 and 26 can be configured as circular substrates at least concentric with the diaphragms 12 and 14 while having a flat plate structure. Therefore, the inner diameter of the housing 18 is determined by the outer diameter dimensions of the oscillation circuit boards 24 and 26 and the diaphragms 12 and 14, and the outer dimensions can be greatly reduced as compared with the case where the pressure sensor 10 is attached to the side wall of the housing. The diameter can be increased.

  In the above embodiment, the substrate housing chamber 52 is formed by extending the cylindrical side wall 34 of the housing 18, but as a separate structure, it is connected to the cylindrical side wall 34 by an appropriate method such as screwing or bonding. May be. Further, the board fixing screw 56 may be configured to be screwed into the side shaft 48.

  Since the pressure sensor 100 according to the second embodiment shown in FIG. 2 only has two oscillation circuit boards 24 and 26 as a single oscillation circuit board 28, the substantial structure is shown in FIGS. The structure is the same.

  FIG. 5 shows a cross-sectional view of a pressure sensor 200 according to the third embodiment. The example shown is an example of a pressure sensor for detecting absolute pressure. That is, the first diaphragm 12 for atmospheric pressure detection of the first embodiment is removed, and the housing is hermetically sealed by simply using the first member as a hermetic terminal block. In particular, the center shaft and the piezoelectric element are arranged concentrically and these are arranged on an axis passing through the central region of the pressure receiving diaphragm, which is different from the previous embodiment.

  The pressure sensor 200 has a housing 218 made of a hollow cylindrical body. In the housing 218, the first member (upper end face plate) is a Herme terminal block 230, and the end face plate constituting the second member (lower end face plate) is a flange end face plate 232 similar to that of the first embodiment. The cylindrical side walls 234 surround the periphery of the end face plates and are configured as hollow sealed containers. In the flange end plate 232, a pressure input port 238 communicating with the internal space is penetrated concentrically with the shaft core of the housing 218 to form a concave portion, and a through hole 240 is formed in the central portion thereof. A pressure receiving diaphragm 214 is fitted to shield the inside and outside of the housing. The diaphragm 214 is bonded and integrally bonded to the inner wall of the recessed portion of the pressure input port 238. The diaphragm 214 is for receiving pressure of the liquid to be measured. The Herme terminal block 230 is configured as an end face plate in which neither the pressure inlet nor the diaphragm is omitted. The housing 218 is also in a state in which the inside and outside are shut off, and the inside can be kept in a vacuum state by an air vent means (not shown) as in the first embodiment.

  Inside the housing 218, a center shaft (force transmission means) 216 is erected vertically in the central region of the inner surface of the diaphragm 214, and is arranged along the axis of the housing 218. A movable portion 244 as a pressure-sensitive element cradle is integrally provided at the distal end portion of the center shaft 216, and the detection shaft is set on the movable portion 244 so as to be coaxial with the center shaft 216. One end of a piezoelectric element 222 made of a tuning fork vibrator is attached. The other end of the piezoelectric element 222 is connected to a base 274 that protrudes inwardly and is provided in the central region of the hermetic terminal block 230 of the housing 218. Thus, when the pressure receiving diaphragm 214 is bent by receiving the pressure of the liquid to be measured, the center shaft 216 moves in the axial direction, and follows this in the direction of the detection axis of the piezoelectric element 222 connected to the movable portion 244. The action force is generated.

  In addition, a plurality of side shafts 248 are arranged in the housing 218 in parallel with the center shaft 216 and around the center shaft 216. These hold the gap between the flange end face plate 232 as the second member and the hermetic terminal block 230 as the first case constant so that the detection accuracy does not deteriorate due to deformation of the housing 218 due to external force or an arbitrary posture. This is the same as in the other embodiments.

  Also in this embodiment, the Herme terminal 250 is passed through the Herme terminal block 230, and the signal of the piezoelectric element 222 is taken out from the sealed space 220 to the substrate housing chamber 252 described later.

  Further, the cylindrical side wall 234 of the housing 218 is raised upward to form a substrate housing chamber 252 at the top of the hermetic terminal block 230, and inside thereof, the piezoelectric circuit oscillation circuit board is parallel to the diaphragm 214. 224, the temperature sensor oscillation circuit board 226 is supported in multiple stages. Each of the oscillation circuit boards 224 and 226 is formed as a disk having a slightly smaller diameter than the Herme terminal block 230, and although not shown, a notch for releasing the air venting means is formed in the same manner as shown in FIG. In addition, a screw through hole through which the fixing screw 256 passes is provided. These oscillation circuit boards 224 and 226 are fixed at a concentric position with the pair of side shafts 248, and the fixing screws 56 are screwed into screw holes formed at corresponding positions of the Herme terminal block 230. It is supposed to be fixed. A gap is formed between the piezoelectric element oscillation circuit board 224 and the Herme terminal block 230, and a spacer 262 is interposed to maintain a gap between the oscillation circuit boards 224 and 226.

  Also in such an embodiment, both the oscillation circuit substrates 224 and 226 can be configured as circular substrates at least concentric with the diaphragm 214 while having a flat plate structure. Therefore, the inner diameter of the housing 218 is determined by the outer diameter dimensions of the oscillation circuit boards 224 and 226 and the diaphragm 214, and the outer dimensions can be greatly reduced as compared with the case where the housing 218 is attached to the side wall of the housing. can do.

  As described above, since the oscillation circuit board is arranged in parallel with the diaphragm, the inner diameter of the housing is only restricted by the diaphragm, and the housing can be reduced in diameter. As a result, for example, as shown in FIG. 6 (b), when applied to an inspection in which the pressure sensor 10 (200) is disposed inside the excavation pipe 300 for groundwater pressure detection, the diameter dimension of the excavation pipe 300 is obtained. Therefore, the cost for excavation work can be reduced.

  In order to sink the pressure sensor 10 (200) into a solution such as groundwater 310 to be measured, a flange end plate 32 (232) is placed around the second diaphragm in the container 330 as shown in FIG. It is mounted through an O-ring 320 arranged so as to surround the screw and is attached by screw tightening.

  In the present embodiment, the temperature compensation circuit for compensating the temperature of the pressure value detected by the resonance frequency of the pressure-sensitive element has been described as an example provided in an external control device. Needless to say, like the circuit board and the temperature sensor oscillation circuit board, the temperature compensation circuit board can be designed as a circular board concentric with the diaphragms 12 and 14 and disposed inside the housing 18.

DESCRIPTION OF SYMBOLS 10 ......... Pressure sensor (1st Embodiment), 12 ......... 1st diaphragm, 14 ......... 2nd diaphragm, 16 ......... Center shaft, 18 ......... Housing, 20 ......... Enclosed space, 22 ......... Piezoelectric element, 24 ......... Oscillator circuit board for piezoelectric element, 26 ......... Oscillator circuit board for temperature sensor, 28 ......... Single oscillator circuit board, 100 ......... Pressure sensor (second embodiment) 30 ......... Herme terminal block, 32 ......... Flange end plate, 34 ......... Cylindrical side wall, 36 ......... First pressure input port, 38 ......... Second pressure input port, 40 ......... Through hole 42 ......... Air venting means 44 ......... Moving part 46 ......... Boss part 48 ......... Side shaft 50 ......... Herme terminal 52 ......... Substrate housing chamber 54 ......... Notch 56 ......... Fixing screw 58 ......... Screw hole 60 ... Screw hole, 62 ......... Spacer, 64 ......... IC, 66 ......... Capacitor, 68 ......... Resistance, 70 ...... Temperature sensor element, 72 ......... IC, 200 ......... Pressure sensor, 214 ... …… Pressure receiving diaphragm, 216... Center shaft, 218... Housing, 220... Sealed space, 222... Piezoelectric element, 224. Oscillating circuit board, 230 ......... Herme terminal block, 232 ......... flange end plate, 234 ......... cylindrical side wall, 238 ......... pressure input port, 240 ......... through hole, 244 ......... movable part, 248 ......... Side shaft, 250 ......... Herme terminal, 252 ......... Substrate housing chamber, 256 ......... Fixing screw, 274 ......... Pedestal.

Claims (7)

  A housing having a pressure input port; and a diaphragm having the pressure input port of the housing sealed and having an outer surface as a pressure receiving surface, and force transmission linked to the deflection of the pressure receiving surface of the diaphragm in the housing And a pressure sensitive element having one end supported by the force transmission means and the other end supported by the housing and having a detection shaft set parallel or coaxial with the pressure receiving surface of the diaphragm. An oscillation circuit board is disposed in parallel with the pressure receiving surface.   A housing having a pair of concentrically arranged pressure input ports, and a pair of concentrically arranged diaphragms that seal the pressure input ports of the housing and have an outer surface as a pressure receiving surface; Is a force transmission means for connecting the pressure receiving surfaces of the diaphragm, and a pressure sensitive sensor having one end connected to the force transmission means and the other end connected to the housing, and a detection shaft set parallel to the pressure receiving surface of the diaphragm. A pressure sensor comprising an element and an oscillation circuit board disposed in parallel with the diaphragm.   A housing having a pressure input port; and a diaphragm having the pressure input port of the housing sealed and having an outer surface as a pressure receiving surface, and force transmission linked to the deflection of the pressure receiving surface of the diaphragm in the housing And a pressure-sensitive element having one end connected to the force transmission means and the other end connected to the housing and having a detection shaft set coaxially with the pressure receiving surface of the diaphragm. A pressure sensor comprising an oscillation circuit board arranged in parallel with a surface.   The pressure sensor according to claim 1, wherein the oscillation circuit board is an oscillation circuit board that drives the pressure-sensitive element.   The oscillation circuit board includes an oscillation circuit board that drives a resonance signal of the pressure-sensitive element and an oscillation circuit board that drives a temperature sensor for temperature correction of the piezoelectric element, and these are arranged in a two-layer structure. The pressure sensor according to any one of claims 1 to 3.   The oscillation circuit substrate is a single-layer substrate in which an oscillation circuit for driving a resonance signal of the pressure-sensitive element and an oscillation circuit for driving a temperature sensor for temperature correction of the piezoelectric element are integrally formed. Item 4. The pressure sensor according to any one of Items 1 to 3.   The pressure sensor according to any one of claims 1 to 6, wherein the pressure-sensitive portion of the pressure-sensitive element includes at least one columnar beam.

Images