CN115014630A

CN115014630A - Pressure measuring device

Info

Publication number: CN115014630A
Application number: CN202210196820.7A
Authority: CN
Inventors: 津岛鲇美
Original assignee: Azbil Corp
Current assignee: Azbil Corp
Priority date: 2021-03-03
Filing date: 2022-03-01
Publication date: 2022-09-06
Anticipated expiration: 2042-03-01
Also published as: CN115014630B; JP2022134312A; KR20220124648A; KR102628745B1

Abstract

The invention provides a pressure measuring device capable of miniaturizing a main body. A pressure measurement device (1) is provided with a main body (2), wherein a pressure sensor chip (23) that detects pressure by receiving the pressure of a pressure transmission medium (25) filled between pressure receiving diaphragms (12, 13), and a sensor case (32) that houses the pressure sensor chip are provided in an internal space (26) of the main body. The sensor case is formed of an insulating material and has an opening portion for introducing a pressure of the pressure transmission medium into the pressure sensor chip. The main body has first and second pressure guide passages (15, 16) leading from the pressure transmission chambers (12, 14) to the inner space. First and second gaskets (17, 18) attached to the opening end of the pressure guide passage, first and second narrow tubes (21, 22), and a substrate (36) on which a circuit for generating an electric signal based on the detection output of the pressure sensor chip is mounted are provided in the internal space. The sensor housing is mounted on the substrate.

Description

Pressure measuring device

Technical Field

The present invention relates to a pressure measuring device including a sensor chip and a substrate in an internal space of a main body.

Background

As a conventional pressure measuring device, for example, there is one described in patent document 1. The pressure measurement device disclosed in patent document 1 includes: a main body provided with a pressure receiving portion that receives a pressure of a fluid to be measured on one end side thereof; a pressure sensor connected to the pressure receiving portion via a pressure guide tube and detecting a pressure of the fluid to be measured; and a circuit substrate on which a circuit related to processing of the electric signal from the pressure sensor is provided. The pressure sensor and the circuit substrate are accommodated inside the main body. The pressure sensor is disposed at a position adjacent to the pressure receiving portion, and the circuit board is disposed at the other end portion of the main body such that the pressure sensor is positioned between the circuit board and the pressure receiving portion.

Documents of the prior art

Patent document

Patent document 1: japanese patent No. 4955394

Disclosure of Invention

Problems to be solved by the invention

In the pressure measurement device disclosed in patent document 1, a space for mounting the pressure sensor and a space for mounting the circuit board are required in the main body, respectively, and therefore, there is a problem that the main body becomes large.

The invention aims to provide a pressure measuring device capable of miniaturizing a main body.

Means for solving the problems

In order to achieve the above object, a pressure measuring apparatus according to the present invention includes a main body including a pressure receiving diaphragm that receives a pressure of a process fluid to be measured, a pressure sensor chip that receives a pressure of a pressure transmission medium filled between the pressure receiving diaphragm and detects the pressure, and a sensor case that houses the pressure sensor chip, wherein the sensor case is formed of an insulating material and has an opening portion for introducing the pressure of the pressure transmission medium into the pressure sensor chip, the main body includes a pressure guide passage that leads from a pressure transmission chamber that is formed as a part of a wall of the pressure transmission chamber and houses a part of the pressure transmission medium into the internal space of the main body, in the inner space of the main body, there are provided: a gasket made of stainless steel, attached to an opening end of the guide passage, which opens into the internal space of the main body, and having a through hole; a narrow tube having one end inserted and joined to the through hole of the gasket and the other end penetrating the opening of the sensor case to communicate with the pressure sensor chip, the narrow tube being filled with the pressure transmission medium; and a circuit board on which a circuit for generating an electric signal based on a detection output of the pressure sensor chip is mounted, wherein the sensor case is mounted on the circuit board.

In the pressure measurement device according to the present invention, the circuit board may have a notch for allowing the narrow tube to pass therethrough at an end portion thereof, and the sensor case may be mounted on the circuit board in a peripheral portion of the notch.

In the pressure measurement device according to the present invention, the circuit board may be fixed to the body in a state in which a direction in which the opening end of the pressure guiding path points is a thickness direction, and a through hole may be formed in the circuit board at a position facing the opening end of the pressure guiding path.

In the present invention, the circuit board may be provided with bonding pads connected to the circuit at three sides thereof, the three sides of the circuit board forming the hole portion surrounding the notch, and the sensor case may be provided with electrode pads connected to the bonding pads and electrically connected to the bonding pads at a bottom surface which is a mounting surface mounted on the circuit board.

ADVANTAGEOUS EFFECTS OF INVENTION

In the present invention, since the sensor case can be mounted on the circuit board, the space occupied by the circuit board and the sensor case can be minimized, and the circuit board and the sensor case can be compactly arranged in the main body. Therefore, a pressure measuring device capable of downsizing the main body can be provided.

Drawings

FIG. 1 is a sectional view of a pressure measuring apparatus according to the present invention.

Fig. 2 is a perspective sectional view of the pressure measuring apparatus.

Fig. 3 is an exploded perspective view showing a main body of the pressure measuring apparatus and a resin case in a cut-away state.

Fig. 4 is a perspective sectional view of the pressure sensor assembly.

Fig. 5 is an enlarged cross-sectional view showing a joint portion between the sensor case and the pressure sensor chip and the capillary tube.

Fig. 6 is an enlarged cross-sectional view showing a joint portion between the gasket and the tubule.

Fig. 7 is a plan view of the pressure sensor assembly and the substrate.

Fig. 8 is a perspective view of the pressure sensor assembly and the substrate.

Fig. 9 is a perspective sectional view for explaining a step of welding the gasket to the body.

Fig. 10 is a plan view of the substrate of the second embodiment.

Fig. 11 is an enlarged plan view of a main portion of the substrate.

Fig. 12 is a perspective view of the pressure sensor assembly and the substrate.

Fig. 13 is a perspective view of the pressure sensor assembly and the substrate.

Fig. 14 is a diagram illustrating a substrate according to a third embodiment.

Fig. 15 is a perspective view of the pressure sensor assembly.

Detailed Description

(first embodiment)

An embodiment of the pressure measuring device according to the present invention will be described in detail below with reference to fig. 1 to 9.

The pressure measurement device 1 shown in fig. 1 is formed by assembling a plurality of functional components described later on a main body 2 depicted in the central portion of fig. 1. The main body 2 has a pressure receiving portion 3 drawn on the lower side in fig. 1 and a detection portion 4 drawn on the upper side. The main body 2 of the present embodiment is made of stainless steel.

The pressure receiving portion 3 is formed in a plate shape having a thickness direction in the left-right direction in fig. 1, and is connected to a first pipe 5 at one end in the thickness direction and a second pipe 6 at the other end in the thickness direction. The first pipe 5 is filled with a first process fluid 7 to be measured. The second pipe 6 is filled with a second process fluid 8 to be measured.

A first pressure receiving diaphragm 11 that receives the pressure of the first process fluid 7 is provided at one end of the pressure receiving portion 3 connected to the first pipe 5, and a first pressure transmission chamber 12 in which the first pressure receiving diaphragm 11 is a part of a wall is formed.

A second pressure receiving diaphragm 13 that receives the pressure of the second process fluid 8 is provided at the other end of the pressure receiving portion 3 connected to the second pipe 6, and a second pressure transmission chamber 14 in which the second pressure receiving diaphragm 13 becomes a part of a wall is formed.

As shown in fig. 2, the first pressure transmission chamber 12 and the second pressure transmission chamber 14 communicate with a pressure chamber 24 (see fig. 5) of the pressure sensor chip 23 via a first guide passage 15 and a second guide passage 16 formed in the main body 2, a first gasket 17 and a second gasket 18 of the detection unit 4 described later, and a first narrow tube 21 and a second narrow tube 22. The pressure transfer system from the first pressure transfer chamber 12 and the second pressure transfer chamber 14 to the pressure chamber 24 is filled with a pressure transfer medium 25 (see fig. 1, 5). The pressure sensor chip 23 detects the pressure by receiving the pressure of the pressure transmission medium 25 filled between the first pressure receiving diaphragm 11 and the second pressure receiving diaphragm 13.

The detection portion 4 of the main body 2 is formed in a cylindrical shape and opens in the direction opposite to the pressure receiving portion 3. An internal space 26 of the main body 2 is formed in the detection part 4. The opening of the detection unit 4 is covered with a cover 27 (see fig. 1), and is closed by the cover 27.

As shown in fig. 3, a first guide passage 15 and a second guide passage 16 are opened in the inner bottom portion of the detection section 4. The first guide passage 15 and the second guide passage 16 are formed inside the body 2 so as to lead from the first pressure transmission chamber 12 and the second pressure transmission chamber 14 to the internal space 26 of the body 2.

As shown in fig. 2, a first gasket 17 is mounted on the open end of the first conduit 15 leading to the inner space 26. A second gasket 18 is mounted at the open end of the second conduit 16 leading to the interior space 26. The first washer 17 and the second washer 18 are each formed of stainless steel into a disc shape and are welded to the body 2.

As shown in fig. 6,

projections

17a and 18a facing the inside of the first guide passage 15 and the second guide passage 16 are provided at the center portions of the first washer 17 and the second washer 18, and through

holes

28 and 29 are formed. As shown in fig. 4, one end of a first narrow tube 21 described later is inserted into and joined to the through hole 28 of the first gasket 17. One end of a second narrow tube 22 described later is inserted into and joined to the through hole 29 of the second gasket 18.

The first narrow tube 21 and the second narrow tube 22 are each formed of stainless steel and bent into a predetermined shape. The first narrow tube 21 and the second narrow tube 22 are joined to the first washer 17 and the second washer 18 by welding the outer peripheral portions of the distal ends of the

narrow tubes

21 and 22 to the opening edges of the through

holes

28 and 29 that open to the

convex portions

17a and 18 a. As shown in fig. 6, the welding is performed so that the first and

second gaskets

17 and 18 and the first and second

narrow tubes

21 and 22 are liquid-tightly sealed by the welding portion 30.

The first narrow tube 21 welded to the first washer 17 and the second narrow tube 22 welded to the second washer 18 constitute a part of a pressure sensor assembly indicated by reference numeral 31 in fig. 4.

As shown in fig. 4, the pressure sensor assembly 31 is configured by the first and

second gaskets

17 and 18 joined to one ends of the first and second

narrow tubes

21 and 22, and the sensor case 32 and the pressure sensor chip 23 joined to the other ends of the first and second

narrow tubes

21 and 22. The first narrow tube 21 and the second narrow tube 22 extend from the first washer 17 and the second washer 18 in the direction opposite to the pressure receiving portion 3 of the body 2, and are bent between the first washer 17 and the second washer 18 and the sensor housing 32 so that the distance between the two

narrow tubes

21 and 22 becomes narrower. The distance between first narrow tube 21 and second narrow tube 22 is increased at one end welded to first washer 17 and second washer 18, and is decreased at the other end joined to sensor housing 32.

The sensor case 32 is configured by a case main body 33 formed of a ceramic material and a lid 34 formed of a ceramic material or a metal material. The pressure sensor chip 23 is formed in a cubic shape by stacking a plurality of plate-like members made of silicon in the thickness direction, and is accommodated in the sensor case 32.

The housing main body 33 of the sensor housing 32 is formed in a bottomed rectangular cylinder shape which is opened upward in fig. 4 and in a direction opposite to the pressure receiving portion 3 of the main body 2. The lid 34 is formed in a plate shape, and is fixed to the case body 33 by brazing, seam welding, or the like in a state where the opening of the case body 33 is closed. To be evacuated or filled with N in the housing body 33 ₂ The operation of joining the lid 34 to the case main body 33 is performed in a manner of being hermetically sealed in a filled state.

As shown in fig. 4, a plurality of electrode pads 35 electrically connected to a plurality of terminals (not shown) of the pressure sensor chip 23 are formed on the bottom surface of the sensor case 32, that is, the case outer surface of the bottom wall 33a of the case main body 33. The electrode pads 35 of this embodiment are disposed at both ends of the bottom wall 33a in the direction orthogonal to the direction in which the first narrow tube 21 and the second narrow tube 22 are aligned.

These electrode pads 35 are overlapped and soldered on soldering pads 37 formed on a substrate 36 (see fig. 3). By performing this soldering, the sensor case 32 is electrically connected (mounted) to the soldering pad 37 in a state of being mounted on the substrate 36. In this embodiment, the substrate 36 corresponds to a "circuit substrate" in the present invention.

As shown in fig. 3, the substrate 36 is formed in a disc shape. The substrate 36 is provided with two circular through

holes

38, 38 through which the first gasket 17 and the second gasket 18 can pass, and a slit 39 connecting the through holes 38. As shown in fig. 2, the through-hole 38 is formed in the substrate 36 at a position facing the opening ends of the first guide passage 15 and the second guide passage 16.

The sensor housing 32 is superposed on the substrate 36 by passing the first and

second gaskets

17, 18 through the through

holes

38, 38 and passing the first and second

narrow tubes

21, 22 through the slit 39. As shown in fig. 7 and 8, a circuit 40 for generating an electric signal based on the detection output of the pressure sensor chip 23 and a connector terminal 41 for external connection are mounted on the substrate 36. Although not shown, a wiring pattern for electrically connecting the soldering pad 37 and the circuit 40 and a wiring pattern for electrically connecting the circuit 40 and the connector terminal 41 are formed on the substrate 36. The positions of the mounting circuit 40 and the connector terminal 41 are not limited to those shown in the drawings, and may be changed as appropriate.

The substrate 36 of this embodiment is supported by a resin case 51 (see fig. 3), and is supported by the main body 2 via the resin case 51. The resin case 51 is formed in a bottomed cylindrical shape that can be accommodated in the internal space 26 of the main body 2. The resin case 51 is provided with a mounting surface 52 on which the substrate 36 is mounted, a claw piece 53 for mounting and locking the substrate 36 on the mounting surface 52, and two through

holes

54, 54 through which the first gasket 17 and the second gasket 18 pass.

Two

circular protrusions

55, 55 protruding downward in fig. 3 from the bottom wall 51a of the resin case 51, that is, in a direction toward the pressure receiving portion 3 of the main body 2, and two

cylindrical bodies

56, 56 protruding in a direction opposite to the pressure receiving portion 3 from the bottom wall 51a of the resin case 51 are provided around the through hole 54. The circular protrusion 55 is fitted into a circular recess 57 formed in the main body 2 so as to surround the first guide passage 15 and the second guide passage 16. A recess 58 for passing the first narrow tube 21 and the second narrow tube 22 is formed in the cylindrical body 56.

In a state where the substrate 36 is mounted on the resin case 51, the first gasket 17 and the second gasket 18 are welded to the main body 2, whereby the substrate 36 is fixed to the main body 2 in a state where the thickness direction of the substrate 36 is the vertical direction in fig. 1. The vertical direction in fig. 1 is a direction in which the open ends of the first guide passage 15 and the second guide passage 16 point.

As shown in fig. 5, the bottom wall 33a of the case main body 33 is formed with a mounting seat 61 for supporting both side portions of the pressure sensor chip 23, and a first opening 62 and a second opening 63 (see fig. 4) for introducing the pressure of the pressure transmission medium 25 into the pressure sensor chip 23.

As shown in fig. 4, the pressure sensor chip 23 has a first hole 64 into which the other end of the first narrow tube 21 is inserted and a second hole 65 into which the other end of the second narrow tube 22 is inserted, and the pressure sensor chip 23 is fixed to the mount base 61 of the housing main body 33 by, for example, soldering. The pressure sensor chip 23 is arranged to detect a pressure difference between the pressure of the pressure transmission medium 25 transmitted to the first hole 64 and the pressure of the pressure transmission medium 25 transmitted to the second hole 65.

The first opening 62 and the second opening 63 of the housing main body 33 are formed as through holes penetrating the bottom wall 33 a. The first opening 62 and the second opening 63 have a diameter that allows the other end of the first narrow tube 21 and the other end of the second narrow tube 22 to pass through. The other end of the first narrow tube 21 penetrates the first opening 62, is inserted into the first hole 64 of the pressure sensor chip 23, and communicates with the pressure sensor chip 23. The other end of the second narrow tube 22 passes through the second opening 63, is inserted into the second hole 65 of the pressure sensor chip 23, and communicates with the pressure sensor chip 23.

As shown in fig. 5, the first narrow tube 21 and the second narrow tube 22 are bonded to the pressure sensor chip 23 with an adhesive 66. As the adhesive 66, an epoxy adhesive can be used. The interior of the sensor case 32 is in a state where the epoxy adhesive does not absorb moisture. The state is a vacuum state or is filled with N ₂ Inert gas such as gas. In order to keep the inside of the sensor case 32 in such an inert state, the portions of the first narrow tube 21 and the second narrow tube 22 that penetrate the first opening 62 and the second opening 63 of the sensor case 32 are sealed by welding. The soldering is performed so that the solder 67 wets and spreads over the entire area around the first opening 62 and the second opening 63.

The first opening 62 and the second opening 63 of the case main body 33 are metallized so that the welding can be performed. In addition, the first narrow tube 21 and the second narrow tube 22 are plated at portions welded to the first opening 62 and the second opening 63. The plating layer for soldering is an Au plating layer using Ni as a base.

Next, a procedure for assembling the pressure measurement device 1 configured as described above will be described. In assembling the pressure measuring device 1, first, the portions of the first narrow tube 21 and the second narrow tube 22 welded to the first opening 62 and the second opening 63 are plated for welding. In addition, the portions of the case main body 33 where the first opening 62 and the second opening 63 are joined to the lid 34 are metallized in advance.

Then, the first washer 17 and the second washer 18 are welded to the first narrow tube 21 and the second narrow tube 22. Thereafter, first narrow tube 21 and second narrow tube 22 are passed through first opening 62 and second opening 63 of case body 33, and first narrow tube 21 and second narrow tube 22 are bonded to pressure sensor chip 23. Then, the pressure sensor chip 23 is bonded to the case main body 33, and the conductive portion between the pressure sensor chip 23 and the case main body 33 is connected by a bonding wire (not shown), for example.

After the pressure sensor chip 23 is mounted on the sensor case 32 in this manner, the first narrow tube 21 and the second narrow tube 22 are welded to the first opening 62 and the second opening 63 of the case main body 33, and the narrow tube penetrating portion is sealed. Then, the case main body 33, the first narrow tube 21, and the second narrow tube 22 are loaded into a not-shown bonding apparatus, the inside of the case main body 33 is made inert, and the lid 34 is attached to the case main body 33 by brazing or seam welding. The pressure sensor assembly 31 is completed by the engagement of the lid 34 with the case main body 33.

The pressure sensor assembly 31 is then mounted on the substrate 36. The mounting operation is performed as follows: the sensor case 32 is welded to the substrate 36 by passing the first and

second gaskets

17 and 18 through the through hole 38 of the substrate 36 and passing the first and second

narrow tubes

21 and 22 through the slit 39. Then, the substrate 36 is locked to the resin case 51, and the resin case 51 is inserted into the internal space 26 of the main body 2. When the substrate 36 is assembled to the resin case 51, the position of the substrate 36 is adjusted so that the first gasket 17 and the second gasket 18 enter the through hole 54 of the resin case 51 while the first gasket 17 and the second gasket 18 are observed through the through hole 38 of the substrate 36. Then, the circular protrusion 55 of the resin case 51 is fitted into the circular recess 57 of the main body 2, and the

convex portions

17a and 18a of the first washer 17 and the second washer 18 are inserted into the first guide passage 15 and the second guide passage 16.

Next, the first washer 17 and the second washer 18 are welded to the body 2. As shown in fig. 9, this welding is performed by resistance welding by placing the body 2 on the lower electrode 71 and pressing the upper electrode 72 against the first gasket 17 and the second gasket 18. The upper electrode 72 is formed in a rod shape, and overlaps the first gasket 17 and the second gasket 18 through the through hole 54 of the resin case 51 and the through hole 38 of the substrate 36. At the tip of the upper electrode 72, a slit 73 is formed to allow the first narrow tube 21 and the second narrow tube 22 to pass therethrough.

After the first and

second gaskets

17, 18 are welded to the body 2, the pressure transmission medium 25 is filled in the pressure transmission path from the first and second

pressure transmission chambers

12, 14 into the pressure sensor chip 23. This filling is performed using a filling hole (not shown) extending from the first pressure transmission chamber 12 and the second pressure transmission chamber 14 to the outside of the main body 2.

The sensor case 32 of the pressure measurement device 1 configured as described above is mounted on the substrate 36. Therefore, since the sensor case 32 can be mounted on the substrate 36, the occupied space of the substrate 36 and the sensor case 32 can be minimized, and the substrate 36 and the sensor case 32 can be compactly arranged in the main body 2. Therefore, according to this embodiment, a pressure measuring apparatus capable of downsizing the main body can be provided.

(second embodiment)

The substrate and the pressure sensor assembly may be configured as shown in fig. 10 to 13. In fig. 10 to 13, the same or equivalent members as those described with reference to fig. 1 to 9 are denoted by the same reference numerals, and detailed description thereof is omitted as appropriate.

The substrate 81 shown in fig. 10 is formed in a disk shape, and has two through holes 38 and a notch 82 located at one position of the outer peripheral portion. The two through

holes

38, 38 are formed at the same positions as in the first embodiment, that is, at positions facing the opening ends of the first guide passage 15 and the second guide passage 16. Further, the circuit 40 and the connector terminal 41 are mounted on the substrate 81. The positions of the mounting circuit 40 and the connector terminals 41 are not limited to those shown in fig. 10, and may be changed as appropriate.

The notch 82 is formed at an end portion in the radial direction of the disc-shaped substrate 81 for passing the first narrow tube 21 and the second narrow tube 22 therethrough, and extends from the outer peripheral edge 81a of the substrate 81 toward the center. The slit 82 of this embodiment extends in a direction orthogonal to an imaginary line L connecting the centers of the two through holes 38. Therefore, the notch 82 extends toward the center between the one through hole 38 and the other through hole 38. The notch 82 includes a first side 82a and a second side 82b extending from the outer peripheral edge 81a of the substrate 81 to the virtual line L, and a third side 82c extending parallel to the virtual line L so as to connect one end of the two sides, and is formed so as to surround the opening portion with the first side 82a to the third side 82 c.

As shown in fig. 11, a plurality of bonding pads 83 are formed on the substrate 81 at the first side 82a where the notch 82 is formed. A plurality of soldering lands 84 are formed on the portion of the substrate 81 where the second side 82b of the notch 82 is formed. A plurality of soldering lands 85 are formed on the portion of the substrate 81 where the third side 82c of the notch 82 is formed. These bonding pads 83 to 85 are connected to the circuit 40 mounted on the substrate 81 via a wiring pattern not shown. The sensor case 32 is mounted on the bonding pads 83 to 85. That is, the sensor casing 32 is mounted and fixed to the periphery of the notch 82 on the substrate 81 in a state where the first narrow tube 21 and the second narrow tube 22 pass through the notch 82.

When the bonding pads 83 to 85 are arranged in a concentrated manner in the vicinity of one side of the notch 82, stress concentration occurs when an external force is applied to the sensor case 32 during the process of manufacturing the pressure measurement device or when thermal stress occurs in the bonding portion due to a change in the ambient temperature. In addition, since the area of the respective bonding surfaces of the electrode pads 35 on the sensor case 32 side is reduced, the process difficulty increases, and the bonding strength of the electrode pads 35 is also reduced. In order to prevent such a problem, in the present embodiment, the bonding pads 83 to 85 are disposed in a dispersed manner at the 3-side portion of the notch 82.

The plurality of bonding pads 83 provided near the first side 82a and the plurality of bonding pads 84 provided near the second side 82b are preferably arranged in bilateral symmetry in fig. 11. Therefore, when the

bonding pads

83 and 84 are asymmetrical, dummy bonding pads not wired are provided on the substrate 81, dummy electrode pads not wired are provided on the sensor case 32, and a bilaterally symmetrical structure is realized. In this embodiment, the bonding pads 85 for passing the sensor signal are provided so as to be arranged along the third side 8 c. With this configuration, efficiency is improved when the sensor case 32 is mounted on the substrate 81.

The first narrow tube 21 and the second narrow tube 22 of this embodiment are formed to be bent as shown in fig. 12 or 13. The first narrow tube 21 and the second narrow tube 22 shown in fig. 12 have two

bent portions

21a, 21b, 22a, and 22b, respectively, and are formed in a figure-of-eight shape as viewed from a direction orthogonal to the main surface 81b of the substrate 81.

The first narrow tube 21 and the second narrow tube 22 shown in fig. 13 have three bent portions 21a to 21c and 22a to 22c, respectively, and are formed in an L shape when viewed from a direction orthogonal to the main surface 81b of the substrate 81.

As shown in this embodiment, by forming notch 82 at the end of substrate 81 and placing and fixing sensor housing 32 on the periphery of notch 82, slit 39 for passing first narrow tube 21 and second narrow tube 22 is not required in substrate 81, and therefore the central portion of substrate 81 can be used as component mounting space 86 (see fig. 10). Therefore, a large number of electronic components can be mounted on the substrate 81 without increasing the size of the substrate 81.

(third embodiment)

The substrate and the pressure sensor assembly are configured as shown in fig. 14 (a), (B), and fig. 15. In fig. 14 and 15, the same or equivalent members as those described with reference to fig. 1 to 13 are denoted by the same reference numerals, and detailed description thereof is omitted as appropriate. Fig. 14 (a) is a side view of the substrate viewed from the front side on which the sensor case is mounted, and fig. 14 (B) is a side view of the substrate viewed from the back side on which the sensor case is not mounted. Fig. 14 (a) and (B) are drawn in a state where the first narrow tube and the second narrow tube are not attached to the sensor housing.

The substrate 91 shown in fig. 14 (a) and (B) is formed in a rectangular plate shape, and has a notch 82 at one end in the longitudinal direction. In fig. 14 (a) and (B), four holes 92 provided in a substrate 91 are holes for passing mounting bolts (not shown). The mounting bolts fix the substrate 91 to a support bracket, not shown, on the main body 2 side. The main surface 91a of the substrate 91 extends parallel to the longitudinal direction of the main body 2 (the direction in which the pressure receiving portion 3 and the detection portion 4 are aligned, and the vertical direction in fig. 14 (a) and (B)), and the notch 82 is fixed to the main body 2 via a support bracket in a posture close to the pressure receiving portion 3.

The substrate 91 is provided with soldering pads 83 to 85 at the portion where the notch 82 is formed, as in the second embodiment, and the sensor case 32 is mounted, placed, and fixed on the soldering pads 83 to 85. As shown in fig. 15, the first narrow tube 21 and the second narrow tube 22 of this embodiment are bent so that the

other end portions

95 and 96 connected to the first washer 17 and the second washer 18 are perpendicular to the one

end portions

93 and 94 connected to the sensor housing 32.

As shown in this embodiment, by disposing the substrate 91 so as to extend parallel to the direction in which the pressure receiving portion 3 and the detection portion 4 of the main body 2 are aligned, the detection portion 4 can be formed compactly so as to reduce the footprint.

Description of the symbols

1 … pressure measuring device, 2 … main body, 7 … first process fluid, 8 … second process fluid, 11 … first pressure receiving diaphragm, 12 … first pressure transmitting chamber, 13 … second pressure receiving diaphragm, 14 … second pressure transmitting chamber, 15 … first pressure transmitting channel, 16 … second pressure transmitting channel, 17 … first gasket, 18 … second gasket, 21 … first thin tube, 22 … second thin tube, 23 … pressure sensor chip, 25 … pressure transmitting medium, 26 … internal space, 28, 29 … through hole, 32 … sensor housing, 35 … electrode pad, 36, 81, 91 … substrate (circuit substrate), 40 … circuit, 62 … first opening portion, 63 … second opening portion, 82 … notch, 38 … through hole, 82a … first edge, 82b … second edge, 82c … third edge, 37, 83 to 85 … for soldering.

Claims

1. A pressure measuring apparatus includes a main body having a pressure receiving diaphragm that receives a pressure of a process fluid to be measured, a pressure sensor chip that detects a pressure by receiving a pressure of a pressure transmission medium filled between the pressure sensor chip and the pressure receiving diaphragm, and a sensor case that houses the pressure sensor chip,

the pressure measuring device is characterized in that,

the sensor case is formed of an insulating material and has an opening portion for introducing the pressure of the pressure transmission medium into the pressure sensor chip,

the body having a pressure transmission chamber formed with the pressure receiving diaphragm as a part of a wall and accommodating a part of the pressure transmission medium,

in the inner space of the main body, there are provided:

a washer made of stainless steel, attached to an opening end of the guide passage leading to the internal space of the main body, and having a through hole;

a narrow tube having one end inserted and joined to the through hole of the gasket and the other end penetrating the opening of the sensor case to communicate with the pressure sensor chip, the narrow tube being filled with the pressure transmission medium; and

a circuit board on which a circuit for generating an electric signal based on a detection output of the pressure sensor chip is mounted,

the sensor case is mounted on the circuit board.

2. The pressure measurement device according to claim 1,

the circuit board has a slit at an end portion thereof for allowing the narrow tube to pass therethrough,

the sensor case is mounted on the circuit board at a peripheral portion of the cutout.

3. The pressure measuring apparatus according to claim 2,

the circuit board is fixed to the main body in a state where a direction in which the opening end of the conductive path points is a thickness direction,

a through hole is formed in the circuit board at a position facing the opening end of the guide passage.

4. Pressure measuring device according to claim 2 or 3,

bonding pads connected to the circuit are provided on the circuit board at three sides of the hole portion surrounding the notch,

an electrode pad connected to and electrically connected to the bonding pad is provided on a bottom surface of the sensor case, which is a mounting surface on the circuit board.