Pressure sensor

Abstract

To easily change at least one of a plurality of measurement ranges.SOLUTION: A pressure sensor 10 includes: a first diaphragm 21 to be deformed by receiving a first pressure P1 of a measured fluid; a second diaphragm 22 to be deformed by receiving a second pressure P2 of the measured fluid; and a plurality of differential pressure sensor chips 61-63 respectively constituted to detect a differential pressure between the first pressure P1 and the second pressure P2 and having a different measurement range. The pressure sensor 10 also includes a pressure transmission member 30 including: a first transmission channel 30A sealed with a first pressure transmission fluid F1 for transmitting the first pressure P1 to each one of the differential pressure sensor chips 61-63; and a second transmission channel 30B sealed with a second pressure transmission fluid F2 for transmitting the second pressure P2 to the respective differential pressure sensor chips 61-63.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] The present invention relates to a pressure sensor.

Background Art

[0002] Patent Document 1 discloses a pressure sensor having a plurality of measurement ranges. In this pressure sensor, a plurality of diaphragms are provided in one differential pressure sensor chip, and the measurement range is changed by switching the diaphragm used for measurement.

Prior Art Document

Patent Document

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] In the pressure sensor described in Patent Document 1, since a plurality of diaphragms are formed in one differential pressure sensor chip, for example, when it is desired to change some of the measurement ranges during the manufacturing stage of the pressure sensor, it is necessary to redesign the entire differential pressure sensor chip. Here, the measurement range of the pressure measured by the pressure sensor often varies depending on the destination of use of the pressure sensor, and it is desirable that the measurement range of the pressure sensor can be easily changed according to the destination of delivery of the pressure sensor.

[0005] The present invention has been made in view of the above points, and an object thereof is to enable easy change of at least one of a plurality of measurement ranges.

Means for Solving the Problems

[0006] To achieve this object, the pressure sensor according to the present invention includes a first diaphragm that deforms by receiving a first pressure of a fluid to be measured, a second diaphragm that deforms by receiving a second pressure of the fluid to be measured, a plurality of differential pressure sensor chips each configured to detect a differential pressure between the first pressure and the second pressure and having different measurement ranges, a first transmission path in which a first pressure transmission fluid for transmitting the first pressure received by the first diaphragm to each of the plurality of differential pressure sensor chips is enclosed, and a second transmission path in which a second pressure transmission fluid for transmitting the second pressure received by the second diaphragm to each of the plurality of differential pressure sensor chips is enclosed, and a pressure transmission member including the same.

[0007] The first transmission path includes a first-1 transmission path having a pressure receiving chamber facing the first diaphragm at a first end, and a first-2 transmission path extending from a second end opposite to the first end of the first-1 transmission path and branching in the middle to reach each of the plurality of sensor chips. The second transmission path includes a second-1 transmission path having a pressure receiving chamber facing the second diaphragm at a first end, and a second-2 transmission path extending from a second end opposite to the first end of the second-1 transmission path and branching in the middle to reach each of the plurality of sensor chips. The pressure transmission member may include a first member forming the first-1 transmission path and the second-1 transmission path, and a second member connected to the first member and forming the first-2 transmission path and the second-2 transmission path.

[0008] Each of the plurality of differential pressure sensor chips includes a sensor diaphragm that is deformed by the differential pressure and a detection element that detects the deformation of the sensor diaphragm. The measurement ranges of the plurality of differential pressure sensor chips are different because at least one of the size, shape, thickness, and material of the sensor diaphragm of each of the plurality of differential pressure sensor chips is different between the plurality of differential pressure sensor chips. The plurality of differential pressure sensor chips include a first differential pressure sensor chip having the highest measurement range of differential pressure and one or more second differential pressure sensor chips having a measurement range on the lower differential pressure side than the measurement range of the first differential pressure sensor chip. At least one of the one or more second differential pressure sensor chips may be provided with an overpressure protection mechanism that prevents the sensor diaphragm deformed by the differential pressure from deforming further by coming into contact with the sensor diaphragm.

Advantages of the Invention

[0009] According to the present invention, the measurement range of the pressure sensor can be changed only by replacing the differential pressure sensor chip, and at least one of the plurality of measurement ranges can be easily changed.

Brief Description of the Drawings

[0010]

Figure 1

Figure 2

Embodiments for Carrying Out the Invention

[0011] Hereinafter, a pressure sensor according to an embodiment of the present invention will be described with reference to the drawings. Note that the vertical direction set in the drawings is set for convenience of explanation and may be different from the actual up and down directions. For example, the pressure sensor may be installed in a direction in which the upper part of FIG. 1 faces the ground side in the up and down direction.

[0012] The pressure sensor 10 according to the present embodiment shown in FIG. 1 detects the differential pressure between a first pressure P1 of the fluid to be measured at a first position of a pipe through which the fluid to be measured flows and a second pressure P2 of the fluid to be measured at a second position of this pipe. The fluid to be measured may be either a liquid or a gas. The pressure sensor 10 transmits the detected differential pressure to the outside. Here, the pressure sensor 10 is configured as a differential pressure transmitter. The transmitted differential pressure is used, for example, for measuring the flow rate of the fluid to be measured. The pressure sensor 10 is arranged such that the first pressure P1 is the pressure on the low-pressure side and the second pressure P2 is the pressure on the high-pressure side.

[0013] As shown in FIG. 1, the pressure sensor 10 includes a first diaphragm 21, a second diaphragm 22, a pressure transmission member 30, a circuit section 40, a circuit housing member 50, and differential pressure sensor chips 61 to 63. In FIG. 1, the second member 32 to be described later, the pin member 42 to be described later, and the differential pressure sensor chips 61 to 63, which should be drawn as cross-sectional views, are drawn as elevation views seen from in front of the plane of FIG. 1.

[0014] The first diaphragm 21 contacts the fluid to be measured having the first pressure P1 drawn in by a predetermined flow path 91 and deforms by receiving the first pressure P1. The second diaphragm 22 contacts the fluid to be measured having the second pressure P2 drawn in by a predetermined flow path 92 and deforms by receiving the second pressure P2. Each of the diaphragms 21 and 22 is fixed to a first surface 31A and a second surface 31B that face each other among the four outer surfaces of a first member 31, which is a square prism and the details of which will be described later, of the pressure transmission member 30.

[0015] The pressure transmission member 30 transmits the pressures P1 and P2 received by the diaphragms 21 and 22, respectively, to each of the differential pressure sensor chips 61 to 63. The pressure transmission member 30 includes a square prism-shaped first member 31 and a second member 32 including bifurcated pipes 32A and 32B connected to the first member 31. The first member 31 is also called a pressure-receiving body. Such a first member 31 has the diaphragms 21 and 22 fixed thereto as described above and receives the first pressure P1 and the second pressure P2 by pressure-receiving chambers S1 and S2 to be described later.

[0016] The pressure transmission member 30 includes a first transmission path 30A including a first-1 transmission path 30AA formed by the first member 31 and a first-2 transmission path 30AB formed by the pipe 32A of the second member 32. In the first transmission path 30A, a first pressure transmission fluid F1 for transmitting the first pressure P1 received by the first diaphragm 21 to each of the differential pressure sensor chips 61 to 63 is enclosed.

[0017] The first-1 transmission path 30AA has, as a first end, a pressure receiving chamber S1 whose surface opposite to the surface of the first diaphragm 21 in contact with the fluid to be measured faces. The pressure receiving chamber S1 is formed by a recess opening to the first surface 31A of the first member 31. The pressure receiving chamber S1 is sealed by the first diaphragm 21. The portion of the first-1 transmission path 30AA other than the pressure receiving chamber S1 is formed by a hole passing through the first member 31. The second end of the first-1 transmission path 30AA opposite to the first end opens to the upper surface of the first member 31. One end of the pipe 32A of the second member 32 forming the first-2 transmission path 30AB is inserted and connected to the second end of the first-1 transmission path 30AA.

[0018] The first-2 transmission path 30AB is formed by the hollow portion of a three-way pipe 32A that branches into three in the middle of the second member 32. One non-branched end of the pipe 32A is connected to the first member 31 as described above. The three other branched ends of the pipe 32A are respectively connected to the pressure input portions on the low-pressure sides of the differential pressure sensor chips 61 to 63. With such a configuration, the first-2 transmission path 30AB extends from the second end of the first-1 transmission path 30AA, branches in the middle, and reaches each of the differential pressure sensor chips 61 to 63.

[0019] The pressure transmission member 30 includes a second transmission path 30B including a second-1 transmission path 30BA formed by the first member 31 and a second-2 transmission path 30BB formed by the pipe 32B of the second member 32. In the second transmission path 30B, a second pressure transmission fluid F2 for transmitting the second pressure P2 received by the second diaphragm 22 to each of the differential pressure sensor chips 61 to 63 is enclosed.

[0020] The second - 1 transmission path 30BA has a first end formed by a pressure - receiving chamber S2 whose surface opposite to the surface in contact with the fluid to be measured of the second diaphragm 22 faces. The pressure - receiving chamber S2 is formed by a recess that opens to the second surface 31B of the first member 31. The pressure - receiving chamber S2 is sealed by the second diaphragm 22. The portion of the second - 1 transmission path 30BA other than the pressure - receiving chamber S2 is formed by a hole passing through the first member 31. The second end of the second - 1 transmission path 30BA, opposite to the first end, opens to the upper surface of the first member 31. One end of a pipe 32B of a second member 32 forming the second - 2 transmission path 30BB is inserted and connected to the second end of this second - 1 transmission path 30BA.

[0021] The second - 2 transmission path 30BB is formed by the hollow portion of a bifurcated pipe 32B that bifurcates into three in the middle of the second member 32. The non - bifurcated end of the pipe 32B is connected to the first member 31 as described above. The three other bifurcated ends of the pipe 32B are respectively connected to the pressure input portions on the high - pressure sides of the differential pressure sensor chips 61 - 63. With such a configuration, the second - 2 transmission path 30BB extends from the second end of the second - 1 transmission path 30BB, bifurcates in the middle, and reaches each of the differential pressure sensor chips 61 - 63.

[0022] The circuit unit 40 controls the operation of the pressure sensor 10. The circuit unit 40 includes a circuit board 41 on which the differential pressure sensor chips 61 - 63 are mounted, a pin member 42 for external connection, and a wiring 43 connecting the circuit board 41 and the pin member 42. The pin member 42 includes a plurality of connection pins 42A connected to the wiring 43 and a support portion 42B in which the connection pins 42A are embedded to support the connection pins 42A.

[0023] The circuit housing member 50 houses the circuit unit 40. The circuit housing member 50 is fixed to the first member 31 of the pressure transmission member 30. The circuit housing member 50 includes a cylindrical member 51 that houses the second member 32, the circuit board 41, and the differential pressure sensor chips 61 to 63 therein, and a lid body 52 that is disposed within the cylindrical member 51 and covers the circuit board 41 and the differential pressure sensor chips 61 to 63. The lid body 52 supports the pin member 42 of the circuit unit 40. The cylindrical member 51 and the lid body 52 form a space S11 for receiving a connector of external wiring that is connected to the connection pin 42A.

[0024] The differential pressure sensor chips 61 to 63 are disposed on the upper surface of the circuit board 41. The pipes 32A and 32B of the second member 32 respectively connected to the differential pressure sensor chips 61 to 63 are routed from the lower surface side to the upper surface side of the circuit board 41 through three through holes formed in the circuit board 41.

[0025] When the first diaphragm 21 is deformed to bulge to the right side of the drawing under the pressure of the first pressure P1, the volume of the pressure receiving chamber S1 facing the first diaphragm 21 decreases. As a result, the first pressure transmission fluid F1 enclosed in the first transmission path 30A including the pressure receiving chamber S1 is pushed toward the differential pressure sensor chips 61 to 63. Thereby, the first pressure P1 received by the first diaphragm 21 is transmitted to each of the differential pressure sensor chips 61 to 63.

[0026] When the second diaphragm 22 is deformed to bulge to the left side of the drawing under the pressure of the second pressure P2, the volume of the pressure receiving chamber S2 facing the second diaphragm 22 decreases. As a result, the second pressure transmission fluid F2 enclosed in the second transmission path 30B including the pressure receiving chamber S2 is pushed toward the differential pressure sensor chips 61 to 63. Thereby, the second pressure P2 received by the second diaphragm 22 is transmitted to each of the differential pressure sensor chips 61 to 63.

[0027] Each of the differential pressure sensor chips 61 to 63 is configured to detect the differential pressure between a first pressure P1 transmitted via a first pressure transmission fluid F1 and a second pressure P2 transmitted via a second pressure transmission fluid F2. The differential pressure sensor chips 61 to 63 have different measurement ranges from each other.

[0028] The differential pressure sensor chip 61 has a low differential pressure measurement range, which is a relatively low differential pressure measurement range. That is, the differential pressure sensor chip 61 is formed as a highly sensitive sensor chip. The differential pressure sensor chip 62 has a medium differential pressure measurement range, which is a measurement range on the higher differential pressure side than the low differential pressure measurement range of the differential pressure sensor chip 61. The differential pressure sensor chip 63 has a high differential pressure measurement range, which is a measurement range on the higher differential pressure side than the medium differential pressure measurement range of the differential pressure sensor chip 62. The differential pressure sensor chips 61 to 63 are also collectively referred to as the differential pressure sensor chip 60. The measurement range may be any range as long as the reliability of the measured value is guaranteed. A part on the higher differential pressure side included in the low differential pressure measurement range and a part on the lower differential pressure side included in the medium differential pressure measurement range may overlap. A part on the higher differential pressure side included in the low differential pressure measurement range and a part on the lower differential pressure side included in the medium differential pressure measurement range may overlap. Thus, the different measurement ranges may partially overlap.

[0029] The structures of the differential pressure sensor chips 61 to 63 are arbitrary. Here, an example of these structures will be described with reference to FIG. 2 as the structure of the differential pressure sensor chip 60. The differential pressure sensor chip 60 has a laminated structure including, for example, a first layer 60A, a second layer 60B, and a third layer 60C as shown in FIG. 2.

[0030] The first layer 60A has a recess 60AA formed on its upper surface and an introduction path 60AB that communicates with the recess 60AA and the first-second transmission path 30AB of the first transmission path 30A shown in FIG. 1 and introduces the first pressure transmission fluid F1 into the recess 60AA. The first layer 60A is formed of, for example, silicon or the like as a material.

[0031] The second layer 60B is formed on the first layer 60A and covers the recess 60AA of the first layer 60A. The portion of the second layer 60B that covers the recess 60AA serves as the sensor diaphragm SD. A detection element D for detecting the displacement of the sensor diaphragm SD is formed in the second layer 60B. The detection element D is composed of, for example, a strain gauge using a semiconductor piezoresistive element. The second layer 60B includes, for example, a main layer made of silicon or the like, an active layer formed by adding impurities to a predetermined region of this main layer and constituting the detection element D, and an insulating protective layer made of silicon oxide or the like formed on the main layer so as to cover this active layer (in FIG. 2, the main layer and the insulating protective layer are depicted as one layer).

[0032] The third layer 60C is formed on the second layer 60B. The third layer 60C has a recess 60CA covered by the second layer 60B and an introduction path 60CB that communicates with the recess 60CA and the second - 2 transmission path 30BB of the second transmission path 30B and introduces the second pressure transmission fluid F2 into the recess 60CA. The introduction path 60CB penetrates the first layer 60A via the second layer 60B and is thereby connected to the second - 2 transmission path 30BB located on the first layer 60A side. The third layer 60C is formed using, for example, silicon or the like as a material.

[0033] The first pressure P1 is applied to the sensor diaphragm SD of the second layer 60B by the first pressure transmission fluid F1 introduced into the recess 60AA of the first layer 60A. The second pressure P2 is applied to the sensor diaphragm SD by the second pressure transmission fluid F2 introduced into the recess 60CA of the third layer 60C. For this reason, the sensor diaphragm SD deforms due to the differential pressure between the first pressure P1 and the second pressure P2. As described above, here, since the first pressure P1 is lower than the second pressure P2, the sensor diaphragm SD deforms so as to bulge toward the first layer 60A side (the lower side in FIG. 2). The detection element D outputs an electrical signal corresponding to the degree of deformation of this sensor diaphragm SD to the circuit board 41 shown in FIG. 1 via wiring (not shown). This electrical signal is, for example, a voltage signal having a voltage value corresponding to the degree of deformation of the sensor diaphragm SD. In this way, the detection element D detects the deformation of the sensor diaphragm SD.

[0034] Returning to FIG. 2, the inner surface Y of the recess 60AA of the first layer 60A contacts the sensor diaphragm SD so that the deformed sensor diaphragm SD that bulges toward the recess 60AA side does not deform any further. Accordingly, the inner surface Y can mechanically suppress excessive deformation of the sensor diaphragm SD due to an excessive differential pressure. Thus, the inner surface Y functions as an overpressure protection mechanism that prevents the sensor diaphragm SD deformed to the allowable upper limit of the degree of deformation from deforming any further. Hereinafter, this inner surface Y is also referred to as the overpressure protection mechanism Y.

[0035] As described above, the differential pressure sensor chips 61 to 63 have different measurement ranges. The different measurement ranges are realized by at least one of the size, shape, thickness, and material of the sensor diaphragm SD being different among the differential pressure sensor chips 61 to 63. Note that the aspect ratio is also included in the shape of the sensor diaphragm SD. The shape of the overpressure protection mechanism Y, that is, the inner surface Y, is naturally appropriately changed according to the shape of the sensor diaphragm SD and the like.

[0036] Of the differential pressure sensor chips 61 to 63, the recess 60AA of the first layer 60A of the differential pressure sensor chip 63 having the highest differential pressure side measurement range may be formed in a shape such that the deformed sensor diaphragm SD does not contact the inner surface Y. That is, the differential pressure sensor chip 63 may not include the overpressure protection mechanism Y. This is because the differential pressure sensor chip 63 has the highest differential pressure side measurement range, and it is difficult for an excessive differential pressure to occur for the differential pressure sensor chip 63. For example, the recess 60AA may have a cubic shape as shown by the dashed-dotted line in FIG. 2.

[0037] When measuring the differential pressure between the first pressure P1 and the second pressure P2, the circuit board 41 in FIG. 1 first determines whether a value such as the voltage value of the electrical signal from the detection element D of the differential pressure sensor chip 61 is equal to or greater than a first threshold value. The first threshold value is preset as the value of the electrical signal corresponding to the upper limit value of the measurement range of the differential pressure sensor chip 61.

[0038] If the above discrimination result is affirmative, the circuit board 41 derives the differential pressure based on the above value. If the discrimination result is negative, the circuit board 41 discriminates whether a value such as the voltage value of the electrical signal from the detection element D of the differential pressure sensor chip 62 is equal to or greater than a second threshold value. The second threshold value is preset as the value of the electrical signal corresponding to the upper limit value of the measurement range of the differential pressure sensor chip 62. The first threshold value and the second threshold value may be, for example, the value of the electrical signal output by the detection element D immediately before the deformed sensor diaphragm SD contacts the inner surface Y of the recess 60AA of the first layer 60A of the differential pressure sensor chip 61 or 62.

[0039] If the discrimination result for the above differential pressure sensor chip 62 is affirmative, the circuit board 41 derives the differential pressure based on the above value. If the discrimination result is negative, the circuit board 41 derives the differential pressure based on a value such as the voltage value of the electrical signal from the detection element D of the differential pressure sensor chip 63.

[0040] Upon receiving any of the above discrimination results, the circuit board 41 outputs the derived differential pressure to the outside, for example, to a host device, via the wiring 43 and the pin member 42 in the form of a DC electrical signal of 4 to 20 mA.

[0041] As described above, in this embodiment, a plurality of measurement ranges are realized by the plurality of differential pressure sensor chips 61 to 63. Therefore, by preparing a plurality of types of differential pressure sensor chips in advance and simply changing the differential pressure sensor chip mounted on the pressure sensor 10, the measurement range of the pressure sensor 10 to be manufactured can be changed. Therefore, at least one of the plurality of measurement ranges of the pressure sensor can be easily changed. As a result, a pressure sensor having a measurement range required by the destination can be easily manufactured. In addition, since a plurality of measurement ranges are mounted on one pressure sensor 10, it is not necessary to prepare a plurality of pressure sensors for each measurement range, and the cost reduction and space saving of the introduction of the pressure sensor are also realized.

[0042] Also, in this embodiment, the transmission paths 30A and 30B for transmitting the pressures P1 and P2 of the diaphragms 21 and 22 are branched corresponding to a plurality of differential pressure sensor chips 60. And, the members constituting the first 1-1 transmission path 30AA and the second 1-1 transmission path 30BA before branching are defined as the first member 31, and the members constituting the first 1-2 transmission path 30AB and the second 1-2 transmission path 30BB are defined as the second member 32. In this way, by separating the members forming the first 1-1 transmission path 30AA and the second 1-1 transmission path 30BA from the members forming the first 1-2 transmission path 30AB and the second 1-2 transmission path 30BB, for the first member 31 forming the first 1-1 transmission path 30AA and the second 1-1 transmission path 30BA, a pressure receiving body or the like used in a conventional differential pressure transmitter can be utilized. Thereby, the structure according to this embodiment can be obtained with a small change from the conventional structure.

[0043] Also, in the above embodiment, the plurality of differential pressure sensor chips 61 to 63 include a first differential pressure sensor chip which is the differential pressure sensor chip 63 having the measurement range on the highest differential pressure side, and one or more second differential pressure sensor chips which are the two differential pressure sensor chips 61 and 62 having a measurement range on the lower differential pressure side than the measurement range of this first differential pressure sensor chip. And, at least one of the one or more second differential pressure sensor chips is provided with an overpressure protection mechanism (inner surface) Y for preventing the sensor diaphragm SD from being further deformed when it comes into contact with the sensor diaphragm SD. There is a trade-off relationship between the measurement range by the sensor diaphragm SD, that is, the measurement sensitivity of the differential pressure, and the pressure resistance. By providing the overpressure protection mechanism Y for the second differential pressure sensor chip having a relatively low differential pressure measurement range, the measurement sensitivity of the differential pressure is increased while ensuring the pressure resistance. Further, excessive deformation of the sensor diaphragm SD is suppressed, and inconveniences such as the sensor diaphragm SD being constantly deflected due to excessive deformation and the measurement accuracy of the differential pressure being reduced are suppressed. Therefore, with the pressure sensor of this embodiment, accurate differential pressure measurement becomes possible.

[0044] Regarding the embodiments described above, various modifications are possible. For example, the shapes of the respective members described in the above embodiments are arbitrary. In the above embodiments, the pressure sensor 10 has three differential pressure sensor chips 61 to 63, but the pressure sensor according to the present invention only needs to include a plurality of differential pressure sensor chips. The differential pressure sensor chip may be a chip that detects differential pressure in a form other than a diaphragm. The plurality of differential pressure sensor chips only need to be configured as separate components from each other. The second member 32 may be formed in a cubic shape, similar to the first member 31. Then, the holes formed in the cubic shape may be used as the first-second transmission path 30AB and the second-second transmission path 30BB. Instead of the first member 31 and the second member 32, a combination of a member that forms all of the first transmission path 30A and a member that forms all of the second transmission path 30B, a member that forms each of all of the first transmission path 30A and the second transmission path 30B, etc. may be adopted. Each of the diaphragms 21 and 22 may be arranged, for example, to face in the vertical direction. The configuration of the overpressure protection mechanism Y is also arbitrary. The overpressure protection mechanism Y may be any configuration that mechanically suppresses excessive deformation of the sensor diaphragm SD, for example.

Explanation of Reference Numerals

[0045] 10… Pressure sensor, 21… First diaphragm, 22… Second diaphragm, 30… Pressure transmission member, 30A… First transmission path, 30AA… First-1 transmission path, 30AB… First-2 transmission path, 30B… Second transmission path, 30BA… Second-1 transmission path, 30BB… Second-2 transmission path, 31… First member, 31A… First surface, 31B… Second surface, 32… Second member, 32A, 32B… Pipes, 40… Circuit section, 41… Circuit board, 42… Pin member, 42A… Connection pin, 42B… Support section, 43… Wiring, 50… Circuit housing member, 51… Cylindrical member, 52… Cover, 60… Differential pressure sensor chip, 60A… First layer, 60AA… Concave portion, 60AB… Introduction path, 60B… Second layer, 60C… Third layer, 60CA… Concave portion, 60CB… Introduction path, 61 to 63… Differential pressure sensor chips, 91, 92… Flow paths, D… Detection element, F1… First pressure transmission fluid, F2… Second pressure transmission fluid, P1… First pressure, P2… Second pressure, S1, S2… Pressure receiving chambers, S11… Space, SD… Sensor diaphragm, Y… Inner surface (overpressure protection mechanism).

Claims

1. A first diaphragm that deforms by receiving a first pressure of a fluid to be measured; A second diaphragm that deforms by receiving a second pressure of the fluid to be measured; A plurality of differential pressure sensor chips each configured to detect a differential pressure between the first pressure and the second pressure and having different measurement ranges; A first transmission path filled with a first pressure transmission fluid that transmits the first pressure received by the first diaphragm to each of the plurality of differential pressure sensor chips, and a second transmission path filled with a second pressure transmission fluid that transmits the second pressure received by the second diaphragm to each of the plurality of differential pressure sensor chips, a pressure transmission member; comprising The first transmission path A first-1 transmission path having a pressure receiving chamber facing the first diaphragm at a first end; A first-2 transmission path extending from a second end opposite to the first end of the first-1 transmission path and branching in the middle to reach each of the plurality of sensor chips; The second transmission path A second-1 transmission path having a pressure receiving chamber facing the second diaphragm at a first end; A second-2 transmission path extending from a second end opposite to the first end of the second-1 transmission path and branching in the middle to reach each of the plurality of sensor chips; The pressure transmission member A first member forming the first-1 transmission path and the second-1 transmission path; A second member connected to the first member and including a first pipe and a second pipe respectively forming the first-2 transmission path and the second-2 transmission path; In the first-1 transmission path, one end of the first member side of the first pipe is inserted into the second end of the first-1 transmission path to be connected to the first-2 transmission path; In the second-1 transmission path, one end of the first member side of the second pipe is inserted into the second end of the second-1 transmission path to be connected to the second-2 transmission path, a pressure sensor.

2. Each of the plurality of differential pressure sensor chips includes a sensor diaphragm deformed by the differential pressure and a detection element that detects the deformation of the sensor diaphragm. At least one of the size, shape, thickness, and material of the sensor diaphragm of each of the plurality of differential pressure sensor chips is different among the plurality of differential pressure sensor chips, so that the measurement ranges of the plurality of differential pressure sensor chips are different. The plurality of differential pressure sensor chips include a first differential pressure sensor chip having the highest differential pressure side measurement range and one or more second differential pressure sensor chips having a measurement range on the lower differential pressure side than the measurement range of the first differential pressure sensor chip. At least one of the one or more second differential pressure sensor chips includes an overpressure protection mechanism that prevents the sensor diaphragm from deforming further when the sensor diaphragm deformed by the differential pressure comes into contact. The pressure sensor according to claim 1.

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