JPH10160607A - Pressure sensor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To sustain airtightness between a pressure introduction pipe and the outside even if burrs are generated at the end part of opening in a base by interposing a metallic washer surrounding the pressure introduction pipe between the the end part of opening in the base and an annular packing. SOLUTION: Since a metallic packing 7 is interposed between the end part 11 of opening in a base and an annular packing 6 while surrounding a pressure introduction pipe 3, the packing 6 does not touch burrs generated at the end part 11 of opening. Consequently, the pressure introduction pipe 3 is sealed with high airtightness by means of the packing 6 to prevent leakage of fluid through the circumferential part of the pressure introduction pipe 3 to the outside thus loading the pressure to a pressure sensor chip 4. When the fluid pressure is loaded to the sensor chip 4, a silicon diaphragm 41 formed in the sensor chip 4 flexes in proportion to the difference between the fluid pressure and the atmospheric pressure. Resistance of a piezoelectric resistor formed on the diaphragm 41 is then varied in proportion to the flexure and thereby the fluid pressure is measured.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a pressure sensor in which a pressure sensor chip converts a change in resistance due to pressure into an electric signal and measures the pressure of a fluid composed of liquid or gas.

[0002]

2. Description of the Related Art Conventionally, as a pressure sensor of this type, FIG.
There exists a thing of a structure shown in FIG. This is a cylindrical base A made of resin and having an open end A1, a glass pedestal B provided with a shaft hole B1 and having one surface orthogonal to the axis of the shaft hole B1, One side perpendicular to the axis of the pressure introduction hole C1 for introducing the target fluid with pressure is joined to one surface of the glass pedestal B, and a flange C3 integrally formed with the open end A1 of the base A. Is one orthogonal plane C2
Pressure introducing pipe C provided on the side and glass pedestal B
Pressure sensor chip D joined to the other surface of the
And a holding case E for holding the pressure introducing pipe C inserted through the insertion hole E1, and between the opening end A1 of the base A and the holding case E in a state surrounding the pressure introducing pipe C. And a ring-shaped packing F that is provided and hermetically sealed.

[0003] More specifically, since the ring-shaped packing F is provided so as to surround the pressure introducing pipe C, the outer peripheral surface of the pressure introducing pipe C, the holding case E, and the opening end A1 of the base A are connected to each other. By contact, the pressure introducing pipe C is hermetically sealed from the outside. Therefore, it is possible to prevent the fluid introduced with pressure into the pressure introducing hole C1 from leaking outside through the outer wall of the pressure introducing pipe C.

Here, the base A has an open end A1 integrally formed with the flange C1 of the pressure introducing pipe C. When the base A is integrally formed, a burr made of resin is generated at the open end A1. ,
It comes into contact with the ring-shaped packing F.

[0005]

In the above-described conventional pressure sensor, the fluid to be measured is prevented from leaking to the outside through the outer wall of the pressure introducing pipe C, and is introduced from the pressure introducing hole C1. Can measure the pressure of a high-pressure fluid.

However, since the burrs generated at the opening end A1 come into contact with the ring-shaped packing F during the integral molding, the ring-shaped packing F and the opening end A1 of the base A are contacted.
In some cases, a gap is formed between the pressure introduction pipe C and the outside, and the introduced fluid leaks from the gap to deteriorate the airtightness between the pressure introduction pipe C and the outside.

SUMMARY OF THE INVENTION The present invention has been made in view of the above problems, and an object of the present invention is to provide airtightness between a pressure introducing pipe and the outside even when burrs are generated at an opening end of a base. Is to provide a pressure sensor that can maintain the pressure satisfactorily.

[0008]

Means for Solving the Problems In order to solve the above-mentioned problems, an object of the present invention is to provide a cylindrical base made of resin, a shaft hole provided and a shaft of the shaft hole. One side perpendicular to the axis of the glass pedestal, which has an orthogonal surface, and the axis of the pressure introduction hole that introduces the fluid to be measured with pressure, is joined to one surface of the glass pedestal, and is integrally formed with the opening end of the base. A metal pressure introducing pipe having a flange portion provided on one orthogonal surface side, a pressure sensor chip joined to the other surface of the glass pedestal, and a pressure introducing hole having an insertion hole and being inserted through the insertion hole. A holding case for holding the pipe, a ring-shaped packing provided between the opening end of the base and the holding case in a state surrounding the pressure introducing pipe and hermetically sealing, and the pressure sensor chip is operated by pressure. Converts resistance changes into electrical signals and measures fluid pressure In the pressure sensor, the pressure introduction pipe outer circumference and a metallic washer is, are in the configuration provided between the ring packing and the base of the open end which is integrally molding the flange portion.

According to a second aspect of the present invention, in the first aspect, the washer has a structure in which an abutting portion that abuts on the flange is protruded.

According to a third aspect of the present invention, in the first or second aspect, the ring-shaped packing is an O-ring having a substantially circular cross section made of synthetic rubber or synthetic resin.

[0011]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A first embodiment of the present invention will be described below with reference to FIGS. Reference numeral 1 denotes a base, which is formed of an insulating resin into an approximately square bottomed cylindrical shape having an opening end 11 and a housing space 12 provided therein.

Reference numeral 2 denotes a glass pedestal, which is formed of a glass such as Pyrex glass into a substantially rectangular cylindrical shape and has a shaft hole 21.
And a surface 22 orthogonal to the axis of the shaft hole 21 is metallized with metal by vapor deposition or sputtering.

Reference numeral 3 denotes a pressure introducing pipe, which is Kovar or FeNi.
A metal, such as an alloy, is formed in a cylindrical shape, and a pressure introduction hole 31 for introducing a fluid to be measured with pressure is provided, and one orthogonal surface 32 orthogonal to the axis of the pressure introduction hole 31 is formed. The axis of the pressure introducing hole 31 and the axis of the shaft hole 21 are aligned with each other, and the one surface 22 of the glass pedestal 2 is soldered.
And are joined.

Further, a flange 33 is provided on one side of the orthogonal surface 32 and is formed integrally with the opening end 11 of the base 1, that is, the flange 33 formed integrally with the opening end 11 of the base 1. On the other hand, it is provided on the orthogonal surface 32 side and is led out to the opposite side of the housing space 12. At this time, the burrs of the base 1 made of resin
It occurs at the open end 11. In addition, the male screw 34 is
Is provided on the outer peripheral portion on the side opposite to the above.

Reference numeral 4 denotes a pressure sensor chip, which is a silicon diaphragm 4 formed at a substantially central portion by a silicon semiconductor.
A strain gauge is formed by arranging a piezoresistor (not shown) on the substrate 1, and the glass pedestal is formed by anodic bonding applying a high DC voltage so that the shaft hole 21 of the glass pedestal 2 is positioned on the silicon diaphragm 41. 2 is connected to the other surface 23 to convert the pressure of the fluid into an electric signal.

As shown in FIG. 2, reference numeral 5 denotes a holding case which is formed of a metal such as stainless steel into a cylindrical shape, and has an insertion hole 51 at a center position. A concave portion 52 having a concentric step leading to the hole is formed to have a hexagonal bolt shape.
The base 1 is accommodated in the recess 52. Further, a fixing screw 5 having a female screw 54a on the inner peripheral portion is provided at the opening end on one side of the insertion hole 51.
4 are provided on the other side, respectively.

Reference numeral 6 denotes a ring-shaped packing, which is formed by an O-ring made of synthetic rubber or synthetic resin into a ring shape and has a circular cross section, and when pressed, elastically deforms and is placed on the tapered portion 53 of the holding case 5. The opening end 11 of the base 1
And the outer peripheral portion of the pressure introducing pipe 3 is located between the pressure introducing pipe 3 and the holding case 5.

Reference numeral 7 denotes a washer, which is formed of a metal into a circular plate having a through hole at the center and has an opening end 1 of the base 1.
1 and a ring-shaped packing 6, and surrounds the pressure introducing pipe 3.

The terminal 8 is fixed to the base 1 and has an internal terminal 81 disposed in the accommodating portion 12 of the base 1 and an external terminal 82 disposed outside and bent. Are electrically connected to electrodes (not shown) provided on the pressure sensor chip 4 by wire bonding.

The printed board 9 is fixed to the concave portion 52 of the holding case 5 by a ceramic substrate on which a circuit is formed, and is electrically connected to the pressure sensor chip 4 by inserting and soldering the external terminals 82. Connected. The terminal block 10 is formed by simultaneously molding the connector terminals 10 a, and the connector terminals 10 a are connected to the terminals 8 via the printed circuit board 9.

The connector 11 is made of a synthetic resin and has a rectangular tubular attaching / detaching portion 11a and a cylindrical pedestal portion 11b having a diameter larger than the outer shape of the attaching / detaching portion 11a. At this time, the connector terminal 10a of the terminal block 10 is
It protrudes into the cylinder 1a and is led out.

Here, the washer 7 is connected to the open end 1 of the base 1.
The internal thread 54a of the fixing screw 54 and the external thread 34 of the pressure introducing pipe 3 are screwed together with the pressure introducing pipe 3 being provided between the first and ring-shaped packings 6 while surrounding the pressure introducing pipe 3. The ring-shaped packing 6 is pressed and elastically deformed uniformly in all directions,
The pressure introducing pipe 3 is hermetically sealed from the outside.

The operation of the above will be described. Pressure introduction hole 3
The first surface 22 of the glass pedestal 2 is soldered to the one orthogonal surface 32 of the pressure introducing tube 3 with solder by aligning the axes of the pressure introducing hole 1 and the shaft hole 21 with solder.
Communicates with In this state, the gas or liquid fluid is introduced into the pressure introducing hole 31 of the pressure introducing pipe 3 with a high pressure.

At this time, the pressure sensor chip 4 is hermetically bonded to the glass pedestal 2 by anodic bonding so as to shield the shaft hole 21 of the glass pedestal 2, and the pressure introducing tube 3 is soldered to the glass pedestal 2. I have. Further, since the metal-free flash washer 7 is provided between the opening end 11 of the base 1 and the ring-shaped packing 6, the ring-shaped packing 6 comes into contact with the burr generated at the opening end 11. Without contacting the washer 7, the outer peripheral portion of the pressure introducing pipe 3, and the tapered portion 53 of the holding case 5. Therefore, since the pressure introducing pipe 3 is hermetically sealed with the outside by the ring-shaped packing 6, the fluid does not leak to the outside through the outer peripheral portion of the pressure introducing pipe 3, and the pressure is transmitted to the pressure sensor chip 4.
To load.

When the pressure of the fluid is applied to the pressure sensor chip 4, the silicon diaphragm 41 formed on the pressure sensor chip 4 bends in proportion to the difference between the pressure of the fluid and the atmospheric pressure. Then, the resistance value of the piezoresistor formed on the silicon diaphragm 41 changes in proportion to the magnitude of the bending, and outputs this resistance value to the terminal 8 as an electric signal. (Not shown) and outputs the amplified signal to the connector terminal 10a to measure the pressure of the fluid.

In the pressure sensor of the first embodiment, as described above, the washer 7 surrounding the pressure introducing pipe 3 is provided between the opening end 11 of the base 1 and the ring-shaped packing 6. Since the burrs formed at the opening end 11 when the base 1 and the flange 33 are integrally formed are in contact with the ring-shaped packing 6, the ring-shaped packing 6 is made of a metal having no burrs. The pressure introducing pipe 3 can be hermetically sealed from the outside by hermetically contacting the washer 7, the outer peripheral surface of the pressure introducing pipe 3, and the tapered portion 53 of the holding case 5.
The life of the ring-shaped packing 6 can be extended.

Since the ring-shaped packing 6 is an O-ring having a circular cross section made of synthetic rubber or synthetic resin,
When the ring is pressed between the washer 7 and the tapered portion 53 of the holding case 5, the ring is uniformly elastically deformed in all directions, and reliably contacts the washer 7, the outer peripheral surface of the pressure introducing pipe 3, and the holding case 5. Thus, the pressure introducing pipe 3 can be hermetically sealed from the outside with high reliability.

A second embodiment of the present invention will be described below with reference to FIG. In the second embodiment, functions different from those in the first embodiment will be described, and members having substantially the same functions as those in the first embodiment will be denoted by the same reference numerals and description thereof will be omitted.

The washer 7 is formed in a circular plate shape with a through hole at the center, and a contact portion 71 is provided to protrude toward the one orthogonal surface 32 of the pressure introducing pipe 3 to surround the pressure introducing pipe 3. In this state, it is provided between the opening end 11 of the base 1 and the ring-shaped packing 6, and comes into contact with the flange 33 of the pressure introducing pipe 3.

In the pressure sensor according to the second embodiment, as described above, the contact portion 71 that comes into contact with the flange 33 of the pressure introducing pipe 3 protrudes from the washer 7, so that the washer 7 comes into contact with the washer 7. The ring-shaped packing 6 reliably contacts the washer 7 because the flatness is good and the flange 33 of the pressure introducing pipe 3 made of metal is not loosened. It can be airtightly sealed.

[0031]

According to the first aspect of the present invention, since the washer surrounding the pressure introducing pipe is provided between the opening end of the base and the ring-shaped packing, the base and the flange are integrally formed. When the burr generated at the opening end contacted the ring-shaped packing, the ring-shaped packing came into contact with each of the burr-free metal washer, the outer peripheral surface of the pressure introducing pipe, and the holding case. In addition, the pressure introducing pipe can be hermetically sealed from the outside with good airtightness, and the life of the ring-shaped packing can be extended.

According to the second aspect of the invention, in addition to the effect of the first aspect, since the contact portion that comes into contact with the flange portion of the pressure introducing pipe is projected from the washer, the washer is a flat contact portion. Because it is in good contact with the metal pressure introducing pipe only without shaking, the ring-shaped packing surely comes into contact with the washer, and the pressure introducing pipe can be hermetically sealed with the outside with high reliability. .

According to the third aspect, in addition to the effects of the first or second aspect, the ring-shaped packing is a circular O-ring made of synthetic rubber or synthetic resin. When pressed between the holding case and the holding case, it is uniformly elastically deformed in all directions, and makes sure contact with the washer, the outer peripheral surface of the pressure introduction tube and the holding case, and the pressure introduction tube is more reliably sealed with the outside. It can be hermetically sealed.

[Brief description of the drawings]

FIG. 1 is a front sectional view showing a first embodiment of the present invention.

FIG. 2 is a front sectional view showing a state where the connector is mounted.

FIG. 3 is a left side view of the same.

FIG. 4 is a front sectional view showing a second embodiment of the present invention.

FIG. 5 is a front sectional view showing a conventional example.

[Explanation of symbols]

 Reference Signs List 1 base 11 open end 2 glass pedestal 21 shaft hole 22 one surface 23 other surface 3 pressure introduction pipe 31 pressure introduction hole 32 one orthogonal surface 33 flange 4 pressure sensor chip 5 holding case 51 insertion hole 6 ring-shaped packing 7 washer 71 Abutment

Continued on the front page (72) Inventor Naohiro Taniguchi 1048 Odakadoma, Kadoma City, Osaka Prefecture Inside Matsushita Electric Works, Ltd.

Claims (3)

[Claims] 1. A base made of resin and formed in a cylindrical shape,
A glass pedestal having an axial hole and having a surface orthogonal to the axis of the axial hole, and one orthogonal surface to the axis of the pressure introducing hole for introducing a fluid to be measured with pressure is joined to one surface of the glass pedestal. Also, a metal pressure introducing pipe having a flange integrally formed with the opening end of the base on one orthogonal surface side, a pressure sensor chip joined to the other surface of the glass pedestal, and an insertion hole are provided. And a holding case for holding the pressure introducing pipe inserted into the insertion hole, and a ring-shaped for airtight sealing provided between the opening end of the base and the holding case in a state surrounding the pressure introducing pipe. A pressure sensor, wherein the pressure sensor chip converts a resistance change caused by the pressure into an electric signal to measure the pressure of the fluid, wherein a metal washer surrounding the pressure introducing pipe integrally forms the flange portion. The open end of the base and the A pressure sensor provided between the pressure sensor and a ring-shaped packing. 2. The pressure sensor according to claim 1, wherein the washer is provided with a contact portion that comes into contact with the flange portion. 3. The pressure sensor according to claim 1, wherein the ring-shaped packing is an O-ring made of synthetic rubber or synthetic resin and having a substantially circular cross section.