JP2018048859A - Pressure sensor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a pressure sensor with which it is possible to measure pressure with high accuracy without being affected by a transient temperature distribution that is generated in a pressure-sensing unit due to a rapid temperature change of a measurement fluid.SOLUTION: The pressure sensor comprises: a pressure-sensing unit in which a diaphragm whose one face is in contact with a measurement fluid is formed; a first strain gauge arranged at center and a second strain gauge arranged at an outer edge on the other face of the diaphragm; a first temperature sensor arranged at center on the other face of the diaphragm in correspondence to the first strain gauge; a second temperature sensor arranged at a position unaffected by stresses due to deflection of the diaphragm; and a correction unit for correcting, using the detection result of the first temperature sensor and second temperature sensor, measured pressure on the basis of the detection result of a bridge circuit formed by the first strain gauge and second strain gauge.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a pressure sensor.

  One type of pressure sensor is a strain gauge type pressure sensor. This pressure sensor includes a pressure-sensitive portion where a diaphragm is formed and a strain gauge formed on the diaphragm. The resistance change of the strain gauge that occurs when the diaphragm in contact with the measurement fluid is bent under pressure is measured. The pressure is detected and measured. In such a pressure sensor, in order to increase the detection sensitivity of the resistance change of the strain gauge, the strain gauge includes a central portion of the diaphragm (a portion that receives tensile stress when the deflection occurs) and an outer edge portion of the diaphragm (the deflection occurs). In many cases, it is connected to a portion that receives a compressive stress in the case of connection and is connected so as to form a bridge circuit (for example, connection by a 4-gauge method).

  Further, many pressure sensors are filled with a sealing liquid such as silicone oil in order to stably measure the pressure of various measurement fluids. However, in the pressure sensor in which the sealed liquid is sealed, when the wetted part is damaged, the sealed liquid inside may leak to the outside. For this reason, in fields where it is necessary to avoid mixing of foreign substances (for example, fields such as food production), pressure sensors without an encapsulated liquid are used (for example, see Patent Document 1 below). In such a pressure sensor, a reference pressure chamber for applying a reference pressure is provided on the other surface of the diaphragm (the surface opposite to the one surface of the diaphragm in contact with the measurement fluid).

  Further, the resistance value of the strain gauge used in the pressure sensor changes according to the temperature. Therefore, in order to improve the pressure measurement accuracy, it is necessary to detect the temperature of the pressure sensor and correct the pressure measurement result (temperature correction) based on the detection result. Here, in the above-described pressure sensor without an encapsulated liquid, since the encapsulated liquid is not encapsulated, it is greatly affected by the temperature change of the measurement fluid. For this reason, in such a pressure sensor, a temperature sensor such as a resistance temperature detector is provided close to the pressure sensor, and the measurement result of the pressure sensor is corrected based on the detection result of the temperature sensor.

JP 2005-148002 A

  By the way, in a pressure sensor in which strain gauges are arranged at the center portion of the diaphragm and the outer edge portion of the diaphragm, when a sudden temperature change of the measurement fluid occurs, the pressure change of the measurement fluid does not actually occur. However, there is a problem that measurement is performed as a pressure change (measurement error occurs). FIG. 7 is a diagram for explaining a pressure measurement error caused by a rapid temperature change of the measurement fluid. As shown in FIG. 7A, the pressure of the measurement fluid remains at P1, but a situation is considered in which the temperature of the measurement fluid has rapidly increased from the temperature T1 to the temperature T2. In such a situation, the pressure measured by the above-described pressure sensor has a maximum ΔP measurement error as shown in FIG. 7B.

  Such a measurement error is caused by a transient temperature distribution in the pressure-sensitive part due to a rapid temperature change of the measurement fluid. FIG. 8 is a diagram for explaining a transient temperature distribution generated in the pressure-sensitive portion. In FIG. 8 (a), the curve with the symbol TA is a diagram showing an example of the temperature change of the strain gauge disposed at the center of the diaphragm, and the curve with the symbol TB is disposed at the outer edge of the diaphragm. It is a figure which shows an example of the temperature change of the made strain gauge. As shown in FIG. 8A, the temperature change TB of the strain gauge arranged at the outer edge of the diaphragm is delayed as compared with the temperature change TA of the strain gauge arranged at the center of the diaphragm. For this reason, a temperature difference shown in FIG. 8B is generated between the strain gauge disposed at the center of the diaphragm and the strain gauge disposed at the outer edge of the diaphragm.

  Here, since the outer edge of the pressure sensing part in contact with the measurement fluid is supported by a support part (not shown), the heat of the measurement fluid is transmitted from the outer edge part of the diaphragm formed in the pressure sensing part toward the support part. Is done. Since the center part of the diaphragm is away from the support part, heat transfer is limited in the center part of the diaphragm. For this reason, the temperature change TA of the strain gauge disposed at the center of the diaphragm increases rapidly as shown in FIG. On the other hand, the outer edge part of the diaphragm is located closer to the support part than the center part of the diaphragm. Therefore, the temperature change TB of the strain gauge arranged at the outer edge of the diaphragm changes with a delay from the temperature change TA of the strain gauge arranged at the center of the diaphragm, as shown in FIG. It becomes. As described above, since there is a difference in heat transfer between the center portion and the outer edge portion of the diaphragm, when a sudden temperature change of the measurement fluid occurs, a concentric temperature distribution is temporarily generated in the diaphragm. A pressure measurement error occurs (see FIG. 7B).

  The above-described temperature correction by the conventional method is a method of correcting the temperature by measuring the temperature at one representative position of the pressure sensor, and thus the measurement error due to the above-described transient temperature distribution cannot be corrected. . Here, if a resistance-type temperature sensor (a sensor that detects a temperature change by detecting a resistance change according to temperature) is formed on the diaphragm, a transient temperature distribution can be measured. It is considered that the measurement error due to the error can be corrected. However, such a temperature sensor is affected by the stress generated by the deflection of the diaphragm (it is affected by the pressure). For this reason, it is impossible to accurately measure only the temperature, and after all, the pressure measurement error cannot be accurately corrected.

  The present invention has been made in view of the above circumstances, and can measure pressure with high accuracy without being affected by a transient temperature distribution generated in the pressure-sensitive portion due to a rapid temperature change of the measurement fluid. An object is to provide a pressure sensor.

In order to solve the above problems, a pressure sensor according to the present invention includes a pressure-sensitive portion (10) having a diaphragm (11) whose one surface (11a) is in contact with a measurement fluid (FL), and the other surface (11b) of the diaphragm. ) And a second strain gauge (G3, G4) disposed at the outer edge, and formed by the first strain gauge and the second strain gauge. In the pressure sensor (1) for measuring the pressure applied to the diaphragm based on the detection result of the bridge circuit (BC), the pressure sensor (1) is disposed at the center of the other surface of the diaphragm corresponding to the first strain gauge. The first temperature sensor (S1), the second temperature sensor (S2, S3) disposed at a position not affected by the stress due to the deflection of the diaphragm, the first temperature sensor, and the first temperature sensor Using the detection results of the temperature sensor comprises a correction unit (32) for correcting the measured pressure based on a detection result of said bridge circuit.
In the pressure sensor according to the present invention, when the second temperature sensor is located between the center portion and the outer edge portion and the diaphragm is bent, both the compressive stress and the tensile stress are applied. It is arranged at the position (X2) where no.
Alternatively, in the pressure sensor of the present invention, the second temperature sensor is located outside the outer edge portion, and the position (X4) where both the compressive stress and the tensile stress do not act when the diaphragm is bent. ).
Or the pressure sensor of this invention is provided with the support part (20) which supports the outer edge of the said pressure sensitive part, and the said 2nd temperature sensor is attached to the said support part.
In the pressure sensor of the present invention, the correction unit is measured based on the detection result of the bridge circuit based on the difference between the detection result of the first temperature sensor and the detection result of the second temperature sensor. Correct the pressure.
In the pressure sensor of the present invention, a plurality of the first strain gauges and a plurality of the second strain gauges are provided, and are arranged symmetrically with respect to the center of the diaphragm.

  According to the present invention, the first temperature sensor is disposed in the central portion of the diaphragm corresponding to the first strain gauge disposed in the central portion of the diaphragm, and the second temperature sensor is not affected by the stress due to the deflection of the diaphragm. A temperature sensor is arranged, and the pressure measured based on the detection result of the bridge circuit formed by the first strain gauge and the second strain gauge is corrected using the detection results of the first temperature sensor and the second temperature sensor. I am doing so. For this reason, there is an effect that it is possible to measure the pressure with high accuracy without being influenced by the transient temperature distribution generated in the pressure-sensitive portion due to the rapid temperature change of the measurement fluid.

It is sectional drawing which shows the principal part structure of the pressure sensor by one Embodiment of this invention. It is a plane perspective view which shows arrangement | positioning of the strain gauge etc. of the pressure sensor by one Embodiment of this invention. It is a figure for demonstrating the specific arrangement | positioning of the temperature sensor by one Embodiment of this invention. It is a figure which shows the electrical constitution of the pressure sensor by one Embodiment of this invention. It is a figure which shows the modification of the pressure sensor by one Embodiment of this invention. It is a figure which shows the other modification of the pressure sensor by one Embodiment of this invention. It is a figure for demonstrating the measurement error of the pressure produced by the rapid temperature change of a measurement fluid. It is a figure for demonstrating the transient temperature distribution which arises in a pressure sensitive part.

  Hereinafter, a pressure sensor according to an embodiment of the present invention will be described in detail with reference to the drawings. In the following description, the positional relationship of each member will be described with reference to the XYZ orthogonal coordinate system (the position of the origin is changed as appropriate) set in the drawing as necessary.

  FIG. 1 is a cross-sectional view showing a main configuration of a pressure sensor according to an embodiment of the present invention. As shown in FIG. 1, the pressure sensor 1 of the present embodiment includes a pressure-sensitive part 10, a support part 20, strain gauges G <b> 1 and G <b> 2 (first strain gauge), strain gauges G <b> 3 and G <b> 4 (second strain gauge), and a temperature sensor. S1 (first temperature sensor S1) and temperature sensor S2 (second temperature sensor) are provided, and the pressure of the measurement fluid FL is measured. Note that the pressure sensor 1 shown in FIG. 1 is a pressure sensor without a sealing liquid such as silicon oil.

  The pressure sensing unit 10 is a part that contacts the measurement fluid FL and senses the pressure of the measurement fluid FL. At the center of the pressure-sensitive portion 10, for example, a diaphragm 11 having a circular shape in plan view (see FIG. 2) and having one surface 11a (a surface on the −Z side) in contact with the measurement fluid FL is formed. The diaphragm 11 is a part to which the pressure of the measurement fluid FL acts, and is configured to bend according to the acted pressure. The diaphragm 11 is made of, for example, a cobalt-nickel alloy material, a silicon-rich austenite-ferrite double-layered stainless steel material, a nickel-molybdenum-chromium alloy material, or a nickel-chromium alloy material in order to realize high corrosion resistance or high pressure resistance. And so on.

  The strain gauges G <b> 1 to G <b> 4 are elements that cause a resistance change according to the strain when the strain is generated by receiving an external stress. The strain gauges G1 and G2 are arranged at the center of the other surface 11b (+ Z side surface) of the diaphragm 11. On the other hand, the strain gauges G3 and G4 are disposed on the outer edge portion of the other surface 11b (+ Z side surface) of the diaphragm 11. FIG. 2 is a perspective plan view showing the arrangement of strain gauges and the like of the pressure sensor according to one embodiment of the present invention.

  As shown in FIG. 2, the strain gauges G <b> 1 to G <b> 4 are arranged symmetrically with respect to the center C of the diaphragm 11 on a straight line passing through the center C of the diaphragm 11 and parallel to the X axis. Specifically, the strain gauge G 1 and the strain gauge G 2 are arranged symmetrically with respect to the center C of the diaphragm 11 at the center of the diaphragm 11, and the strain gauge G 3 and the strain gauge G 4 are connected to the diaphragm 11 at the outer edge of the diaphragm 11. They are arranged symmetrically with respect to the center C.

  The strain gauges G1 and G2 disposed at the center of the diaphragm 11 receive tensile stress when the diaphragm 11 is bent, and the strain gauges G3 and G4 disposed at the outer edge of the diaphragm 11 are attached to the diaphragm 11. When bending occurs, it receives compressive stress. The reason why the strain gauges G1 to G4 are arranged in this manner is to increase the detection sensitivity of the resistance change of the strain gauges G1 to G4. As such strain gauges G1 to G4, a metal strain gauge using a metal foil or a thin wire which is an isotropic conductor, or a semiconductor strain gauge using a piezoresistance effect of a semiconductor can be used.

  The temperature sensor S1 is disposed at the center of the other surface 11b (+ Z side surface) of the diaphragm 11 corresponding to the strain gauges G1 and G2, and the temperature at the center of the diaphragm 11 (temperature of the strain gauges G1 and G2) is measured. It is a sensor to detect. The temperature sensor S2 is a sensor that is disposed at an outer edge portion of the other surface 11b (+ Z side surface) of the diaphragm 11 corresponding to the strain gauge G4, and detects a temperature at the outer edge portion of the diaphragm 11 (temperature of the strain gauge G4). is there. As shown in FIGS. 1 and 2, the temperature sensor S1 is disposed between the strain gauge G2 and the strain gauge G4 at a position close to the strain gauge G2, and the temperature sensor S2 includes the strain gauge G2 and the strain gauge G4. It is arranged at a position close to the strain gauge G4.

  FIG. 3 is a diagram for explaining a specific arrangement of the temperature sensor according to the embodiment of the present invention. When the diaphragm 11 bends due to the pressure of the measurement fluid FL, stress corresponding to the position acts on the strain gauges G1 to G4 and the temperature sensors S1 and S2 provided on the diaphragm 11. Specifically, as shown in FIG. 3, tensile stress acts on the strain gauge G <b> 2 disposed at the center portion (position X <b> 1) of the diaphragm 11, and the strain gauge disposed at the outer edge portion (position X <b> 3) of the diaphragm 11. A compressive stress acts on G4. Similar to the strain gauge G2, the temperature sensor S1 is arranged at a position where tensile stress acts.

  Here, neither compression stress nor tensile stress acts at the position X2 between the position X1 where the strain gauge G2 is disposed and the position X3 where the strain gauge G4 is disposed. The temperature sensor S2 is disposed at a position X2 where neither the compressive stress nor the tensile stress acts (or in the vicinity of the position X2 where both the compressive stress and the tensile stress hardly act). The temperature sensor S2 is arranged at such a position so that the temperature at the outer edge portion of the diaphragm 11 (temperature of the strain gauge G4) is accurately determined so as not to be affected by the stress caused by the deflection of the diaphragm 11. This is to detect. Then, by performing temperature correction using the temperature detected by the temperature sensor S2 as a reference temperature, high accuracy can be achieved without being affected by a transient temperature distribution (see FIG. 3) caused by a sudden temperature change of the measurement fluid FL. This is because the pressure is measured.

  When a sudden temperature change of the measurement fluid FL occurs, for example, as shown in FIG. 3, the temperature at the center portion (position X1) of the diaphragm 11 becomes highest, and the temperature gradually increases toward the outer edge portion (position X3) of the diaphragm 11. A concentric temperature distribution in which the temperature becomes low temporarily occurs. Note that a position X4 in FIG. 3 indicates a position outside the outer edge of the diaphragm 11.

  The support part 20 is a member that is attached to the + Z side of the pressure-sensitive part 10 and supports the outer edge of the pressure-sensitive part 10. By attaching the support part 20 to the pressure-sensitive part 10, a reference pressure chamber R is formed between the support part 20 and the pressure-sensitive part 10. In addition, a hole H is formed in the central portion of the support portion 20, and a reference pressure P 0 from the outside is supplied to the reference pressure chamber R through the hole H. As a result, the pressure of the measurement fluid FL acts on one surface 11a of the diaphragm 11 formed in the pressure-sensitive portion 10, the reference pressure P0 acts on the other surface 11b of the diaphragm 11, and the diaphragm 11 It bends according to the difference between the pressure and the reference pressure P0.

  FIG. 4 is a diagram showing an electrical configuration of a pressure sensor according to an embodiment of the present invention. As shown in FIG. 4, the pressure sensor 1 includes a bridge circuit BC constituted by strain gauges G1 to G4, an A / D (analog / digital) converter 31, and a calculation unit 32 (correction unit). The bridge circuit BC is a circuit configured by connecting the strain gauges G1 to G4 by the 4-gauge method. In this bridge circuit BC, one end of the strain gauges G1, G3 is connected to the power source Vcc, one end of the strain gauges G2, G4 is grounded, or is connected to a common potential of the electric circuit, and the other end of the strain gauges G1, G4 is connected The strain gauges G2 and G3 are connected to the output terminal Q1, and the other ends of the strain gauges G2 and G3 are connected to the output terminal Q2.

  The A / D converter 31 is a three-channel A / D converter having three input terminals and one output terminal, and individually converts an analog signal input from each input terminal into a digital signal. The converted digital signal is individually output from the output terminal. Output terminals Q1 and Q2 of the bridge circuit BC are connected to one input terminal of the A / D converter 31, and temperature sensors S1 and S2 are connected to the remaining two input terminals, respectively.

  The computing unit 32 measures the pressure of the measurement fluid FL based on the digital signal output from the A / D converter 31. Specifically, the pressure of the measurement fluid FL is obtained based on the detection signal (digital signal) of the bridge circuit BC output from the A / D converter 31. Then, using the detection signals (digital signals) of the temperature sensors S1 and S2 output from the A / D converter 31, the obtained pressure of the measured fluid FL is corrected.

  For example, the calculation unit 32 relates the difference between the detection results of the temperature sensors S1 and S2 (see the temperature difference shown in FIG. 8B) and the pressure measurement error (see the measurement error ΔP shown in FIG. 7B). Is stored in advance. And based on the difference of the detection signal of temperature sensor S1, S2, the pressure of the calculated | required measurement fluid FL is correct | amended using said table or a relational expression. The reason for performing such correction is to correct a pressure measurement error caused by a transient temperature distribution and measure the pressure with high accuracy.

  In the pressure sensor 1 having the above configuration, when the pressure of the measurement fluid FL is applied to the diaphragm 11, the diaphragm 11 is bent. Then, tensile stress acts on the strain gauges G1 and G2 disposed at the center of the diaphragm 11, and compressive stress acts on the strain gauges G3 and G4 disposed on the outer edge of the diaphragm 11. As a result, the resistance values of the strain gauges G1 to G4 change, and the voltage between the output terminals Q1 and Q2 of the bridge circuit BC shown in FIG. 4 changes.

  The voltage between the output terminals Q1 and Q2 of the bridge circuit BC is converted into a digital signal by the A / D converter 31 and input to the arithmetic unit 32. Then, the calculation unit 32 performs a calculation for obtaining the pressure of the measurement fluid FL (pressure applied to the diaphragm 11) based on the digital signal from the A / D converter 31. When the pressure of the measurement fluid FL is obtained, a signal indicating the pressure of the measurement fluid FL is output from the calculation unit 32 to the outside.

  It is assumed that a sudden temperature change of the measurement fluid FL occurs during the measurement operation described above (see FIG. 7A). When such a rapid temperature change occurs, a concentric temperature distribution is temporarily generated in the diaphragm 11 (see FIG. 3), thereby causing a pressure measurement error (see FIG. 7B). The temperature at the center of the diaphragm 11 (temperature of the strain gauges G1 and G2) is detected by the temperature sensor S1, and the temperature at the outer edge of the diaphragm 11 (temperature of the strain gauge G4) is detected by the temperature sensor S2.

  The detection results of these temperature sensors S1 and S2 are converted into digital signals by the A / D converter 31 and input to the arithmetic unit 32. The calculation unit 32 obtains the difference between the detection results of the temperature sensors S1 and S2 based on the difference between the detection signals of the temperature sensors S1 and S2 using a table or a relational expression indicating the relationship between the pressure measurement errors. The pressure of the measurement fluid FL is corrected. When the pressure of the measurement fluid FL is corrected, a signal indicating the corrected pressure of the measurement fluid FL is output from the calculation unit 32 to the outside.

  As described above, in the present embodiment, the first temperature sensor is disposed at the center portion of the diaphragm corresponding to the first strain gauge disposed at the center portion of the diaphragm, and the second strain disposed at the outer edge portion of the diaphragm. A second temperature sensor is arranged at the outer edge of the diaphragm corresponding to the gauge, and the pressure measured based on the detection result of the bridge circuit BC is corrected using the detection result of the first temperature sensor and the second temperature sensor. I am doing so. As a result, even if a transient temperature distribution occurs in the diaphragm 11 due to a sudden temperature change of the measurement fluid FL, the pressure error due to this transient temperature distribution can be corrected. Can be measured with high accuracy.

  Although the pressure sensor according to the embodiment of the present invention has been described above, the present invention is not limited to the above-described embodiment, and can be freely changed within the scope of the present invention. For example, in the above-described embodiment, the example in which the temperature sensor S <b> 2 is arranged at the position X <b> 2 (see FIG. 3) where the stress generated when the diaphragm 11 is bent is described. However, instead of such a temperature sensor S2, a temperature sensor S3 (second temperature sensor) shown in FIG. 5 may be provided.

  FIG. 5 is a view showing a modification of the pressure sensor according to one embodiment of the present invention. As shown in FIG. 5, in this modification, a temperature sensor S <b> 3 such as a resistance temperature detector is attached to the support unit 20. The position where the temperature sensor S <b> 3 is attached is a position that is not affected by the stress due to the deflection of the diaphragm 11. In addition, the attachment position of temperature sensor S3 with respect to the support part 20 is arbitrary. In this modification, the calculation unit 32 shown in FIG. 4 uses the detection result of the temperature sensor S1 on the diaphragm 11 and the detection result of the temperature sensor S3 attached to the support unit 20 to calculate the pressure of the measurement fluid FL. It will be corrected. In this modification, the temperature sensor S2 is not necessary.

  In this modification, the temperature sensor S3 is disposed at a position (supporting portion 20) that is separated from the strain gauge disposed on the diaphragm 11, but is not affected by the stress due to the deflection of the diaphragm 11. Further, the temperature detected by the temperature sensor S3 disposed on the support unit 20 is substantially the same as the temperature detected by the temperature sensor S2 of the above-described embodiment, and is not extremely different. For this reason, the temperature of the pressure sensor 1 can be measured stably. Then, the temperature detected by the temperature sensor S3 is used as a reference temperature, and the temperature correction is also performed using the detection result of the temperature sensor S1, so that a transient temperature distribution caused by a rapid temperature change of the measurement fluid FL (see FIG. 3) ), The pressure can be measured with high accuracy.

  In addition, referring to FIG. 3, it can be seen that a position where the stress generated by the deflection of the diaphragm 11 does not act exists at a position outside the outer edge portion of the diaphragm 11 (position X4). For this reason, the temperature sensor S2 shown in FIG. 3 may be arranged at the position X4 instead of the position X2. If the temperature sensor S2 is arranged at the position X4, the temperature sensor S2 can be arranged at a position closer to the strain gauge than the temperature sensor S3 shown in FIG. 5, and therefore the pressure can be measured with higher accuracy.

  FIG. 6 is a view showing another modification of the pressure sensor according to one embodiment of the present invention. FIG. 6 is a perspective plan view showing the arrangement of strain gauges and the like of the pressure sensor, as in FIG. In the example shown in FIG. 2, the strain gauges G <b> 1 to G <b> 4 and the temperature sensors S <b> 1 and S <b> 2 are arranged on a straight line passing through the center C of the diaphragm 11 and parallel to the X axis. However, as shown in FIG. 6, the strain gauges G1 to G4 are arranged on a straight line parallel to the X axis passing through the center C of the diaphragm 11, and the temperature sensors S1 and S2 are arranged on the Y axis passing through the center C of the diaphragm 11. You may arrange | position on a parallel straight line. However, in the arrangements shown in FIGS. 2 and 6, since the stress distribution and the temperature distribution are concentric, respectively, the distance of the temperature sensor S <b> 1 with respect to the center C of the diaphragm 11 is the same, and the temperature with respect to the center C of the diaphragm 11 is the same. The distance of sensor S2 should just be the same.

  In the above-described embodiment, the planar views of the strain gauges G1 to G4 and the temperature sensors S1 and S2 are rectangular. However, the planar view shapes of the strain gauges G1 to G4 and the temperature sensors S1 and S2 are not limited to a rectangular shape, and may be other shapes. For example, the strain gauges G1 to G4 and the temperature sensors S1 and S2 may be formed in an arc shape with the center C of the diaphragm 11 as the center.

  Further, in the above-described embodiment, the example in which the two strain gauges G1 and G2 are provided in the central portion of the diaphragm 11 and the two strain gauges G3 and G4 are provided in the outer edge portion of the diaphragm 11 has been described. However, the number of strain gauges provided at the center and outer edge of the diaphragm 11 may be one each, or may be three or more.

DESCRIPTION OF SYMBOLS 1 Pressure sensor 10 Pressure sensing part 11 Diaphragm 11a One side 11b Other side 20 Support part 32 Calculation part BC Bridge circuit FL Measuring fluid G1-G4 Strain gauge S1-S3 Temperature sensor

Claims (6)

A first pressure gauge disposed at a central portion of the other surface of the diaphragm, and a second strain gauge disposed at an outer edge of the diaphragm. In a pressure sensor that measures a pressure applied to the diaphragm based on a detection result of a bridge circuit formed by a strain gauge and the second strain gauge,
A first temperature sensor disposed at the center of the other surface of the diaphragm corresponding to the first strain gauge;
A second temperature sensor disposed at a position not affected by stress due to the deflection of the diaphragm;
A correction unit that corrects the pressure measured based on the detection result of the bridge circuit using the detection result of the first temperature sensor and the second temperature sensor;
A pressure sensor.   The said 2nd temperature sensor is a position between the said center part and the said outer edge part, Comprising: When the bending of the said diaphragm arises, it arrange | positions in the position where both a compressive stress and a tensile stress do not act. The pressure sensor according to 1.   2. The pressure according to claim 1, wherein the second temperature sensor is disposed at a position outside the outer edge portion and at a position where neither compressive stress nor tensile stress acts when the diaphragm is bent. Sensor. A support portion for supporting an outer edge of the pressure-sensitive portion;
The second temperature sensor is attached to the support;
The pressure sensor according to claim 1.   The correction unit corrects a pressure measured based on a detection result of the bridge circuit based on a difference between a detection result of the first temperature sensor and a detection result of the second temperature sensor. The pressure sensor according to claim 4.   The pressure sensor according to claim 1, wherein a plurality of the first strain gauges and a plurality of the second strain gauges are provided, and are arranged symmetrically with respect to a center of the diaphragm.

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