JP2004045076A - Pressure sensor - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a pressure sensor for reducing the number of part items and manufacturing manhours by simplifying a structure of a pressure sensor body. <P>SOLUTION: A semiconductor pressure sensor outputs a voltage signal according to pressure from a pressure sensor element by transmitting the pressure applied from an external part to a pressure detecting chamber to a semiconductor pressure sensor element via liquid by sealing the liquid in the pressure detecting chamber 21 for housing the semiconductor pressure sensor element 41. A pressure sensor body part is formed by integrating a cover member 1 having a pressure introducing pipe 19, a diaphragm 3 for receiving the pressure and a holder 2 for fixing a semiconductor pressure sensor to an inside space 21 by welding. The diaphragm 3 and the cover member 1 or the holder 2 and a reinforcing plate 32 are integrally welded by applying the reinforcing plate 32 to a back face of a contact plane of the diaphragm 3. <P>COPYRIGHT: (C)2004,JPO

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a pressure sensor, and more particularly, to a structure of a pressure sensor including a housing and a connector case, in which a liquid is sealed in an indirect pressure receiving chamber containing a pressure detection element.
[0002]
[Prior art]
Conventionally, a liquid is sealed in a pressure detection chamber in which a semiconductor pressure sensor element is housed, and a pressure applied from the outside to the pressure detection chamber is transmitted to the semiconductor pressure sensor element via the liquid, so that this pressure sensor element Various semiconductor pressure detectors that output a voltage signal according to pressure have been proposed.
[0003]
For example, “Applications and Product Trends of Semiconductor Pressure Sensors” (December Issue of Sensor Technology, Vol. 11, No. 12 (pp. 72-76), Nov. 11, 1991, issued by Information Research Group, Inc.) "A housing having a pressure detection chamber for hermetically sealing a pressure transmitting medium (filled liquid), a pressure-sensitive element (chip) for outputting a signal corresponding to pressure, and a signal between the pressure-sensitive element and the outside. A signal transmitting means (terminal) for transmitting and receiving, the pressure-sensitive element is provided in the pressure chamber, and the signal transmitting means electrically connected to the pressure-sensitive element is held in a stem, and the pressure-sensitive element is connected to the pressure-sensitive element. "Semiconductor pressure detectors that send and receive signals to and from the outside,""A signal processing circuit that performs amplification, adjustment, and temperature characteristic compensation around a silicon diaphragm equipped with a diffusion-type strain gauge. Electrically connected to the pressure element Providing a processing circuit for "it is shown.
[0004]
Furthermore, Japanese Patent Application Laid-Open No. 5-149814 discloses a sensor in which a strain gauge and a circuit element of a signal processing circuit are integrated, and this sensor is surrounded by a seal diaphragm and a container and filled with an insulating oil such as silicone oil. A semiconductor pressure sensor disposed in a space is disclosed.
[0005]
In such a conventional semiconductor pressure detector in which a pressure-sensitive element and a signal processing circuit are provided in a sealed liquid, no consideration has been given to improving airtightness and reducing the number of assembly steps.
[0006]
Therefore, the present applicant has filed a Japanese Patent Application No. 2002-092250 for a pressure sensor that realizes a pressure receiving space and a pressurizing space with a simple configuration and has no leakage. That is, the pressure sensor according to the present application seals a liquid in a pressure detection chamber in which a semiconductor pressure sensor element is housed, and applies a pressure externally applied to the pressure detection chamber to the semiconductor pressure sensor element via the liquid. In the semiconductor pressure sensor that outputs a voltage signal corresponding to the pressure from the pressure sensor element, a lid member having a pressure introduction unit, a diaphragm that receives the pressure, and a holder that fixes the semiconductor pressure sensor to an internal space. Are integrated by welding to form a pressure sensor main body.
[0007]
[Problems to be solved by the invention]
SUMMARY OF THE INVENTION An object of the present invention is to provide a pressure sensor which realizes a pressure receiving space and a pressurizing space with a simple configuration and has excellent airtightness. Still another object of the present invention is to provide a pressure sensor, in which a diaphragm forming a pressure receiving space and a lid member or a holder are firmly joined.
[0008]
[Means for Solving the Problems]
In order to achieve this object, the pressure sensor of the present invention encloses a liquid in a pressure detection chamber in which a semiconductor pressure sensor element is housed, and applies a pressure externally applied to the pressure detection chamber via the liquid. A semiconductor pressure sensor that outputs a voltage signal corresponding to the pressure from the pressure sensor element by transmitting the voltage to the semiconductor pressure sensor element, wherein a lid member having a pressure introduction unit, a diaphragm that receives the pressure, and a semiconductor pressure sensor The holder fixed in the space is integrated by welding to form the pressure sensor main body, and when the diaphragm is airtightly joined to the lid member or holder, a reinforcing plate is applied to the back of the joint surface of the diaphragm and they are welded together I did it.
[0009]
With such a structure, the welded portion of the diaphragm 3 is reinforced by the reinforcing plate 32, and the diaphragm forming the pressure receiving space and the lid member or the holder can be firmly joined.
[0010]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, a first embodiment of a pressure sensor according to the present invention will be described with reference to FIG. FIG. 1 is a longitudinal sectional view showing the configuration of the pressure sensor according to the first embodiment.
[0011]
The pressure sensor according to the first embodiment of the present invention includes a lid member 1, a holder 2, a diaphragm 3, and a pressure sensor disposed in a pressure receiving space (pressure detection chamber) 21 formed inside the holder 2. It comprises means 4 and a connector case 6.
[0012]
The lid member 1 is made of, for example, stainless steel, and is formed in a disk shape with its periphery rising and being a flat flange. An opening is provided at the center of the lid member 1, and a pressure introducing pipe 19 communicating with the pressurizing space 11 is brazed. Reference numeral 191 denotes a welded portion.
[0013]
The holder 2 is made of, for example, stainless steel and has a pot shape, and a space formed therein serves as a pressure receiving space 21 filled with liquid. A plurality of extraction member through holes 23 and a liquid injection hole 24 are formed at the bottom of the holder 2. The liquid injection hole 24 has a valve receiving portion 26 formed in the middle, and a pin fixing portion 25 is further provided on the upper portion. In this embodiment, a female screw is cut in the pin fixing portion 25. A side opening 27 is formed above the valve receiving portion 26, and functions as a liquid draining and air releasing means when the pressure receiving space is sealed.
[0014]
At the bottom of the pressure receiving space 21 of the holder 2, a glass pedestal 42 is fixed to the surface of the printed wiring board 43, and the semiconductor pressure sensor element 41 is fixed thereon. It is fixed by bonding.
[0015]
The extraction member 5 is inserted into the extraction member through hole 23 of the holder 2, and is hermetically fixed by the hermetic seal 53.
[0016]
The pressure sensor element 41 has a semiconductor substrate having a rectangular planar shape, a thin central portion, a diaphragm portion deformed by pressure, and a plurality of diaphragm portions on the upper surface of the diaphragm portion. By forming the piezoresistive element in a bridge shape, a pressure sensing part, which is a strain gauge, is formed, and an electric circuit such as an amplifier circuit or an arithmetic processing circuit manufactured by using an integrated circuit manufacturing technology is formed on the peripheral thick part. A circuit is provided.
[0017]
Further, a land portion (not shown) provided on the upper surface of the pressure sensor element 41 and a land portion (not shown) provided on the upper surface of the printed wiring board 43 are connected by bonding wires 51. Further, a land portion (not shown) provided on the surface of the printed wiring board 43 and the lead-out member 5 are connected by a bonding wire 52.
[0018]
The diaphragm 3 is formed of, for example, a thin plate of stainless steel that deforms when pressure is applied, and is formed in a disk shape. A reinforcing plate 32 is applied to the back surface of the joining surface of the peripheral portion 31 of the diaphragm 3, and is provided on the bottom surface 12 of the lid member 1 together with the reinforcing plate 32 at a welded portion 33 by TIG welding, plasma welding, laser welding, or the like. It is welded and joined tightly and tightly.
[0019]
The holder 2 is arranged on the bottom surface 12 of the lid member 1 to which the diaphragm 3 is fixed by welding, and the annular ridge 22 formed at the lower portion of the holder 2 is joined and fixed by projection welding.
[0020]
A pressure receiving space 21 formed by the joined holder 2 and the diaphragm 3 is filled with a liquid as a pressure transmission medium, for example, an insulating oil such as silicone oil via a liquid injection hole 24, and further sealed in the liquid injection hole 24. After the stop ball 8 is thrown in, the sealing screw 80 is fixed to the pin fixing portion 25 and the sealing ball 8 is fixed to the valve receiving portion 26 to be sealed.
[0021]
The caulking portion 17 of the lid member 1 is caulked to the caulking receiving portion 28 of the holder 2, and the lid member 1 and the holder 2 are fixed together with welding.
[0022]
In the semiconductor pressure sensor element 41, a piezoresistor is formed on the surface of the semiconductor substrate so as to form a bridge, and a closed space for pressure detection is formed on the back surface of the semiconductor substrate.
[0023]
The connector case 6 is a resin case to which the connector 7 is fixed, and a terminal support 79 to which the connector 7 is fixed is arranged.
[0024]
The lead-out member 5 is connected to the energization connection 71 provided at the other end of the connector 7 by caulking or spot welding.
[0025]
The connector case 6 is formed in a substantially cylindrical shape using, for example, a nylon resin.
[0026]
Hereinafter, an assembly process of the pressure sensor will be described. First, the diaphragm 3 is positioned on the bottom surface 12 of the lid member 1 in which the pressure introducing pipe 19 is brazed to the opening. Further, the reinforcing member 32 is disposed thereon, and the diaphragm 3 is welded to the lid member 1 together with the reinforcing member 32 at the welding portion 33.
[0027]
On the other hand, in the pressure receiving space 21 of the holder 2 in which the extraction member 5 is fixed to the extraction member through hole 23 with a hermetic seal, the pressure detection unit 4 including the semiconductor pressure sensor element 41, the pedestal 42, and the printed wiring board 43 is fixed by bonding. Then, the land provided on the surface of the printed wiring board 43 and the lead-out member 5 are connected by the bonding wires 52.
[0028]
After the annular ridge 22 of the holder 2 is disposed on the bottom surface 12 of the lid member 1, the pressure sensor main body is formed by being hermetically bonded and integrated by projection welding.
[0029]
Thereafter, a liquid such as a fluorine oil or a silicone oil is filled into the pressure receiving space 21 formed by the diaphragm 3 and the holder 2 constituting the pressure receiving chamber from the liquid injection hole 24, and then the sealing ball 8 is placed on the valve receiving portion 26. The liquid injection hole 24 is sealed by screwing the sealing screw 80 into the pin fixing portion 25 and fixing it. Excess liquid and air are discharged from the side opening 27 when the screw 80 is screwed.
[0030]
Thereafter, the caulking portion 17 of the lid member 1 is caulked on the caulking receiving portion 28 of the holder 2 to integrate the lid member 1 and the holder 2.
[0031]
A terminal support 79 is placed on the holder 2 of the pressure sensor main body, and the lead-out member 5 and the current-carrying connection 71 of the connector 7 are connected by caulking or spot welding. Thereafter, the connector case 6 is placed from above to form a pressure sensor.
[0032]
According to the present invention, the pressure sensor can be manufactured with high airtightness by using a small number of parts and a small number of manufacturing steps.
[0033]
The configuration of the pressure sensor according to the second embodiment of the present invention will be described with reference to FIG. In the second embodiment, in the pressure sensor according to the first embodiment, the connection between the extraction member 5 and the connector 7 is performed by press-contacting with a spring member 72 such as phosphor bronze. Are the same as those of the first embodiment shown in FIG. 1, and the same components are denoted by the same reference numerals. At a portion of the spring member 72 that is in contact with the extraction member 5, a good conductive portion 73 having improved conductivity by applying gold plating or the like is formed.
[0034]
The configuration of the pressure sensor according to the third embodiment of the present invention will be described with reference to FIG. The third embodiment is an embodiment in which the shape of the liquid injection mechanism is changed in the pressure sensor according to the first embodiment. That is, in this embodiment, the sealing pin 81 is press-fitted into the pin fixing portion 25 and fixed, and the sealing ball 8 is pressed into contact with the valve receiving portion 26 and fixed by the sealing pin 81. An air vent groove 82 is formed in the sealing pin 81. Other configurations are the same as those of the first embodiment, and the same components are denoted by the same reference numerals.
[0035]
A configuration of a pressure sensor according to a fourth embodiment of the present invention will be described with reference to FIG. In the fourth embodiment, the liquid sensor is omitted from the pressure sensor according to the first embodiment. Other configurations are the same as those of the first embodiment, and the same components are denoted by the same reference numerals.
[0036]
In the present embodiment, the manufacturing process is devised by omitting the liquid injection mechanism. That is, when the lid member 1 to which the diaphragm 3 is welded and the holder 2 to which the pressure detecting means 4 is fixed by welding, the output of the pressure detecting means 4 fixed in the holder 2 is adjusted. Next, the holder 2 is arranged upside down as shown in the figure, and the pressure receiving space 21 is filled with a pressure transmitting medium (liquid), and the lid member 1 is put on the pressure receiving space 21 so as to cover the bottom surface 12 of the lid member 1. The two are welded and fixed by projection welding while keeping the 22 in contact. Thereafter, the caulking portion 17 is caulked to the caulking receiving portion 28, and the lid member 1 and the holder 2 are integrally fixed.
[0037]
The configuration of the pressure sensor according to the fifth embodiment of the present invention will be described with reference to FIG. The fifth embodiment is different from the pressure sensor according to the third embodiment in that the sealing pin 81 of the liquid injection mechanism is more securely fixed, and a caulking portion 29 is formed around the opening of the pin fixing portion 25. After the pressure medium is injected, the upper end of the sealing pin 81 is caulked and fixed by the caulking portion 29. Other configurations are the same as those of the third embodiment, and the same components are denoted by the same reference numerals.
[0038]
A configuration of a pressure sensor according to a sixth embodiment of the present invention will be described with reference to FIG. In the sixth embodiment, in the pressure sensor according to the second embodiment, the cover member 1 and the pressure introducing pipe are integrated, and at the lower end of the pressure introducing section, a pipe (not shown) is provided with a screw or the like. A screwing portion 18 is provided which is fixed by the screw. Further, the lid member 1 may be directly fixed by the screwing portion 18. Other configurations are the same as those of the second embodiment, and the same components are denoted by the same reference numerals.
[0039]
A configuration of a pressure sensor according to a seventh embodiment of the present invention will be described with reference to FIG. The seventh embodiment is characterized in that, in the pressure sensor according to the third embodiment, the pressure receiving space 21 is formed by welding and fixing the diaphragm 3 to the welding surface 211 provided on the holder 2. ing. That is, in this embodiment, the diaphragm 3 is not welded to the lid member 1 but to the holder 2. Also in this case, the reinforcing plate 32 is applied to the back surface of the joint surface of the diaphragm 3 and these are integrally welded. The welding method is performed by a method such as laser beam welding or electron beam welding as in the embodiments described above. Other configurations are the same as those of the third embodiment, and the same components are denoted by the same reference numerals.
[0040]
The configuration of a pressure sensor according to an eighth embodiment of the present invention will be described with reference to FIG. The eighth embodiment is an example in which the pressure receiving space 21 is configured by the same structure as the seventh embodiment in the pressure sensor according to the second embodiment. Other configurations are the same as those of the seventh embodiment, and the same components are denoted by the same reference numerals.
[0041]
As described above, the present invention can select and combine various aspects of the following a to e.
[0042]
A. As shown in the first embodiment, the pressure receiving space is constructed by welding the diaphragm 3 to the lid member 1 and welding the lid member 1 and the holder 2 by the annular ridge 22 in the seventh embodiment. As shown in (1), any one of the embodiments in which the diaphragm 3 is welded to the holder 2 can be adopted.
[0043]
I. The connection between the pull-out member 5 and the connector 7 is such that a current-carrying connection portion 71 provided at the other end of the connector 7 shown in the first embodiment is connected to the pull-out member 5 by caulking or spot welding. As shown in the embodiment, it is possible to adopt any one of the modes in which the connection between the extraction member 5 and the connector 7 is made by pressing the spring member 72 into contact.
[0044]
C. The liquid injection mechanism is formed by caulking the sealing pin 80 shown in the first embodiment, the sealing pin shown in the third embodiment, and the sealing pin 81 shown in the fifth embodiment. Either the mode of attaching the liquid or the mode in which the liquid injection mechanism described in the fourth embodiment is omitted can be adopted.
[0045]
D. The configuration of the lid member 1 employs either the mode in which the pressure introducing pipe 19 shown in the first embodiment is provided by brazing or the mode in which the pressure introducing pipe shown in the sixth embodiment is integrally provided to form a screw. can do.
[0046]
E. In the first to eighth embodiments, the processing circuit of the pressure detecting means 4 is provided separately from the semiconductor pressure sensor element and the printed wiring board 43. All of the pressure sensor elements 41 may be mounted.
[0047]
【The invention's effect】
As described above, the present invention reduces the number of parts and reduces the number of assembly steps by forming the pressure sensor body by welding and integrating the lid member, the diaphragm, and the holder, thereby reducing the number of assembly steps and improving the airtight pressure. A sensor can be provided.
[0048]
Further, according to the present invention, since the reinforcing member is disposed on the back surface of the diaphragm and is integrally welded, the diaphragm and the lid member or the diaphragm and the holder can be firmly joined.
[Brief description of the drawings]
FIG. 1 is a longitudinal sectional view showing a structure of a pressure sensor according to a first embodiment of the present invention.
FIG. 2 is a longitudinal sectional view showing a structure of a pressure sensor according to a second embodiment of the present invention.
FIG. 3 is a longitudinal sectional view showing the structure of a pressure sensor according to a third embodiment of the present invention.
FIG. 4 is a longitudinal sectional view showing a structure of a pressure sensor according to a fourth embodiment of the present invention.
FIG. 5 is a longitudinal sectional view showing the structure of a pressure sensor according to a fifth embodiment of the present invention.
FIG. 6 is a longitudinal sectional view showing the structure of a pressure sensor according to a sixth embodiment of the present invention.
FIG. 7 is a longitudinal sectional view showing the structure of a pressure sensor according to a seventh embodiment of the present invention.
FIG. 8 is a longitudinal sectional view showing the structure of a pressure sensor according to an eighth embodiment of the present invention.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Cover member 11 Pressurized space 12 Bottom surface 17 Caulking part 18 Screwing part 19 Pressure introducing pipe 191 Welded part (brazed part)
2 Holder 21 Pressure receiving space 22 Annular ridge 23 Pull-out member through hole 24 Liquid injection hole 25 Pin fixing part 26 Valve receiving part 27 Side opening 28 Caulking receiving part 29 Caulking part 3 Diaphragm 31 Peripheral part of diaphragm 32 Reinforcement plate 33 Welding part 4 Pressure detecting means 41 Semiconductor pressure sensor element 42 Pedestal 43 Printed wiring board 5 Lead-out member 51, 52 Bonding wire 53 Hermetic seal 6 Connector case 7 Connector 71 Conductive connection part 72 Spring member 73 Good conductive part 79 Support base 8 Sealing ball 80 Seal Set screw 81 Sealing pin 82 Air vent groove

Claims (1)

A liquid is sealed in a pressure detection chamber in which a semiconductor pressure sensor element is housed, and a pressure applied from the outside to the pressure detection chamber is transmitted to the semiconductor pressure sensor element via the liquid. In a semiconductor pressure sensor that outputs a voltage signal according to pressure,
A lid member having a pressure introduction part, a diaphragm receiving pressure, and a holder fixing the semiconductor pressure sensor in the internal space are integrated by welding to form a pressure sensor main body, and the diaphragm is welded to the lid member or the holder. A semiconductor pressure sensor wherein a reinforcing member is integrally welded while standing.

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