JP4863571B2 - Pressure sensor - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a pressure sensor, and more particularly to a structure of a pressure sensor that can be easily assembled for the purpose of reducing the number of assembly steps in a pressure sensor including a housing accommodating a pressure detection element and a connector case.
[0002]
[Prior art]
In Japanese Patent Laid-Open No. 11-351990, as an absolute pressure type pressure sensor or a shield gauge pressure type pressure sensor for detecting the pressure of a fluid, a metal made of an internal space communicating with the pressure detection space and a thin upright portion at the upper end is disclosed. The housing, the pressure case and the connector are composed of a housing, a partition that separates the inner space from the upper and lower sides, a cylindrical metal pressure case having a thin upright portion at the upper end, and a connector case made of an insulating material. There has been disclosed a pressure sensor in which a sensor element and an electric circuit for pressure detection are housed in an internal space formed by stacking cases and caulking the respective upper portions, and providing a through capacitor in the pressure case.
[0003]
Further, the present applicant aims to reduce the fluctuation of the influence of electromagnetic noise on the output voltage of the pressure sensor described above, a housing having a pressure introduction hole, a sensor element made of a semiconductor element having a piezoresistance effect, A holder for fixing the sensor element; and a pressure case; the sensor element, the holder, and the pressure case are hermetically welded to form a pressure space for reference, and the pressure sensor body is An invention relating to a pressure sensor electrically insulated and held in a housing has been filed as Japanese Patent Application No. 11-312611.
[0004]
According to the present invention, the influence of electromagnetic noise of the pressure sensor can be reduced, but the configuration of the portion connecting the pressure sensor main body and the connector is complicated and the number of man-hours is increased, and the manufacturing cost is not reduced. ing.
[0005]
[Problems to be solved by the invention]
In order to meet such a demand, the present invention has an object to provide a pressure sensor that simplifies the structure of a portion connecting a pressure sensor main body and a connector and reduces the number of manufacturing steps.
[0006]
[Means for Solving the Problems]
In order to achieve such an object, a pressure sensor of the present invention includes a housing having a pressure introducing hole, a pressure detection element made of a semiconductor element having a piezoresistive effect, and the pressure detection element fixed through a base and a header. A pressure sensor body having a holder and a connector case, wherein the pressure sensor body and the holder are hermetically joined via a pedestal and a header to form a reference pressure space; A circuit board having an electrode pad is provided on the holder, and includes a spring-like body having electrical conductivity supported by the connector case, and the spring-like body is disposed in a reference pressure space; One end is fixed to the lower end of the connector provided in the connector case, the other end is bent downward, and the tip is formed by a curved portion. The holder provided with the pressure detecting element and the circuit board is placed on the housing from its inner space, and then the connector case is placed over the housing and inserted into the inner space to be fixed, and the spring The curved portion of the body is pressed onto the electrode pad .
[0008]
Further, according to the present invention, the portion from the portion fixed to the lower end of the connector of the spring-like body to the bent portion is supported by the bottom portion of the internal space of the connector case.
[0009]
Furthermore, the present invention, the pressure sensor, Ru gauge pressure type pressure sensor der.
[0010]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, a first embodiment of a pressure sensor according to the present invention will be described with reference to FIGS. 1 is a longitudinal sectional view showing a configuration of a gauge pressure type pressure sensor according to a first embodiment, FIG. 2 is a top view of a circuit board and a holder, FIG. 3 is a bottom view of a connector case, and FIG. 4 is an electrode pad. It is a figure explaining a connection state with a spring-like object.
[0011]
The pressure sensor 1 according to the first embodiment of the present invention includes a housing 10, a sensor element 20, a holder 30, a circuit board 40, a spring-like body 50, a connector case 70, and a connector 80. Has been.
[0012]
In the pressure sensor 1, a pressure sensor main body including a sensor element 20 and a holder 30 is housed in a container including a housing 10 and a connector case 70.
[0013]
The housing 10 is configured in a substantially cylindrical shape using, for example, aluminum. The housing 10 has a fluid introduction hole 12 for introducing a fluid at a lower portion, and a circular housing bottom portion 13 is formed at an upper portion of the fluid introduction hole, and is formed by an annular bank 141 provided in the periphery thereof. An annular groove 14 serving as an O-ring and connector case receiving part, a peripheral wall 16 rising from the outer periphery of the annular groove, a caulking part 17 provided thinly at the upper end of the peripheral wall, and a bottom part and a peripheral wall on the inner side of the main body And a housing internal space 18 formed.
[0014]
The fluid introduction hole port 12 of the housing 10 and the housing internal space 18 communicate with each other.
[0015]
A screw portion 19 provided on the outer periphery of the fluid introduction hole 12 of the housing 10 is screwed into the pipe on the measurement pressure side to fix the housing 10 to the pipe in an airtight manner.
[0016]
The sensor element 20 has a function of detecting pressure, and is a pressure composed of a metal header 21 and a semiconductor element provided with a plurality of piezoresistive resistors on the upper surface of the semiconductor substrate so as to form a bridge. The detection element 22 and a silicon pedestal 23 that is airtightly fixed to the upper surface of the header 21 are provided. ing.
[0017]
The pedestal 23 is mounted and fixed on the upper surface 213 of the header 21 in an airtight manner, and the pressure detection element 22 is mounted and fixed on the upper surface of the pedestal 23 so that the surface on which the resistor is disposed is the upper surface.
[0018]
Around the lower portion of the header 21, a collar portion 211 having a holder receiving bank 212 formed in a closed shape on the upper surface is provided.
[0019]
The pressure detection element 22 has a planar shape of the semiconductor substrate formed in a rectangular shape, a thin central portion, and a diaphragm portion that is deformed by pressure. A plurality of diaphragms are formed 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 using integrated circuit manufacturing technology on the thick part of the peripheral part. A circuit is provided.
[0020]
Further, a land portion provided on the upper surface of the pressure detection element 22 and a land portion 43 provided on the upper surface of the circuit board 40 are connected by a bonding wire 25.
[0021]
For example, the silicon pedestal 23 is formed in a shape in which the planar shape is rectangular and the sensor element opening 24 is provided at the center.
[0022]
A gold plating layer is provided on the joint surface of the silicon base 23 with the header 21 by gold sputtering or the like.
[0023]
The header 21 is made of, for example, an iron-nickel alloy such as 42 alloy, has a circular planar shape, and is formed in a shape having a sensor element opening 24 at the center. A gold plating layer is provided on the joint surface of the header 21 with the base 23.
[0024]
The pedestal 23 and the sensor element opening 24 of the header 21 are arranged coaxially, communicate with the fluid introduction hole 12 of the housing 10, and are configured to guide pressure fluid to a space provided on the back surface of the pressure detection element 22. Yes.
[0025]
The lower surface of the pressure detecting element 22 is hermetically welded and fixed to the upper surface of the pedestal 23, and the lower surface of the pedestal 23 and the upper surface 213 of the header 21 are heat-pressed (scrubbed) with a gold-silicon brazing material interposed therebetween. -A silicon alloy is formed and is hermetically welded and fixed.
[0026]
The holder 30 forms a reference pressure space together with the connector case 70.
[0027]
The holder 30 is formed using, for example, stainless steel, a holder opening 32 is provided at the center, and a positioning notch 33 that determines the position of the connector case is provided at a part of the periphery.
[0028]
The lower surface 31 of the holder 30 is brought into contact with the upper surface of a holder receiving bank 212 provided on the flange portion 211 of the header 21 of the sensor element 20, and is fixed in an airtight manner, for example, by projection welding.
[0029]
The circuit board 40 is fixed to the upper surface 34 of the holder 30 using an adhesive or the like.
[0030]
The circuit board 40 is made of an insulating printed wiring board made of, for example, an alumina board, and is formed in a substantially disk shape, and a circuit board opening 41 in which the pressure detection element 22 of the sensor element 20 is located is provided at the center. On the surface, an electrode pad 42 made of a gold pad for taking out a signal to the outside, a land portion 43 made of a gold pad to which a bonding wire 25 from the pressure detecting element 22 is connected, and an electric signal from the pressure detecting element 22 are amplified and amplified. A printed wiring 44 and a circuit element 45 constituting a circuit that performs arithmetic processing and outputs are provided. The circuit portion of the circuit board 40 is covered with a protective film 46 as indicated by broken lines except for the electrode pads 42, the land portions 43, and the inspection terminal portions.
[0031]
The electrode pad 42 serving as an input / output terminal provided on the circuit board 40 is connected to the connector 80 when the spring-like body 50 is in contact therewith, and is provided corresponding to the signal line, the power supply line, and the ground line.
[0032]
The spring-like body 50 is made of an electrically conductive elastic body such as phosphor bronze, and one end 51 is fixed to the lower end 81 of the connector 80 by spot welding or the like, and the other end is bent downward to form a hanging part 52. A bending portion 53 is formed at the tip portion. A surface of the bending portion 53 that contacts the electrode pad 42 is partially plated with gold.
[0033]
The spring- like body 50 is supported by the bottom surface 74 of the connector case 70 from the end portion 51 to the bent portion 52 so that the curved portion 53 is pressed onto the electrode pad 42 when the connector case 70 is caulked to the housing 10. To work.
[0034]
The connector case 70 is a resin case into which the connector 80 is inserted and fixed. The connector case 70 hangs downward from a socket portion 71 provided at the top, a connector case internal space 72 serving as a reference space provided below the socket portion 71, and the connector case 70. The upper peripheral wall 73, the lower surface 74 of the upper peripheral wall 73, the lower peripheral wall 75 that hangs down below the upper peripheral wall 73, the caulking receiving portion 76 provided on the outer upper side of the lower peripheral wall 75, and the positioning provided on the inner surface of the lower peripheral wall 75 It has a portion 77, a flat surface 78 at the lower end of the lower peripheral wall 76, and a connector insertion hole 79 for inserting and holding the connector 80. The connector 80 is inserted into the connector insertion hole 79 from below and fixed.
[0035]
Although not shown, the pressure in the reference space communicates with the outside (atmospheric pressure) through the gap (equal pressure equalization path) between the connector 80 and the connector insertion hole 79, thereby achieving a gauge pressure type pressure sensor. Of course, the pressure equalizing path may be the minimum necessary size to transmit the pressure.
[0036]
The connector case 70 can correspond to various different shapes of connectors by changing its shape.
[0037]
In the connector 80, a power supply line and a ground line are used for supplying power to the electric circuit, and the ground line and the signal line are used for taking out an output signal of the sensor element 20 to the outside.
[0038]
The O-ring 95 is inserted into the annular groove 14 that is an O-ring receiving groove, and prevents water, moisture, and the like from the outside from entering the internal space 72 of the connector case 70. The O-ring 96 is fitted on the upper portion of the screw portion 19 of the housing, and maintains an airtightness with the pipe.
[0039]
A procedure for assembling the pressure sensor 1 using these components will be described.
[0040]
The sensor element 20 assembled by fixing the laminated body of the pressure detection element 22 and the pedestal 23 onto the header 21 is inserted into the holder opening 32 of the holder 30, and the holder receiving bank 212 provided in the collar portion 211 of the header 21. Then, the annular projection electrode is pressed against the holder lower surface 31, and the header 21 is hermetically welded to the holder lower surface 31 and fixed.
[0041]
Next, after fixing the circuit board 40 to the upper surface 34 of the holder 30 using an adhesive, the land portion of the pressure detection element 22 and the land portion 43 of the circuit board 40 are connected using the bonding wire 25 made of a gold wire. .
[0042]
The pressure sensor assembly comprising a sensor element 20 and the holder 30 and the circuit board 40, the housing 10 placing the O-ring 95 you location mounting than the housing inner space 18. The connector case 70 provided with connection means is assembled by inserting the connector 80 having the spring-like body 50 fixed to the lower end portion 81 into the connector insertion hole 79 of the connector case 70.
[0043]
Next, after positioning the curved portion 53 of the spring-like body 50 fixed to 80 on the terminal fixed to the connector case 70 so as to be positioned on the electrode pad 42 of the circuit board 40, the connector case 70 is fixed to the housing 10. The housing 10 and the connector case 70 are fixed by caulking the caulking portion 17 at the upper end of the rising portion (peripheral wall portion) 16 of the housing 10 onto the caulking receiving portion 76 of the connector case 70.
[0044]
Through the above steps, the pressure sensor 1 in which the connector 80 and the electrode pad 42 are electrically connected is assembled.
[0045]
According to the present invention, after the pressure sensor assembly is positioned in the housing 10, the connector case 70 is covered from above and the caulking portion 17 of the housing is caulked, whereby the fluid introduction space is hermetically configured. A pressure sensor for pressure can be easily manufactured without going through a process such as soldering of lead wires.
[0046]
In the reference example of the present invention, the gauge pressure type pressure sensor in the first embodiment is an absolute pressure type and shield gauge pressure type pressure sensor.
[0047]
The configuration of an absolute pressure type and shield gauge type pressure sensor 1 according to a reference example of the present invention will be described with reference to FIGS. FIG. 5 is a longitudinal sectional view showing the entire configuration of the pressure sensor, and FIG. 6 is an enlarged sectional view of a mounting portion of the pressure case of the absolute pressure type and shield gauge pressure type pressure sensors.
[0048]
The pressure sensor 1 according to the reference example is provided with a pressure case 60 in an airtight manner in the gauge pressure type pressure sensor 1 according to the first embodiment shown in FIG. It is characterized in that absolute pressure and shield gauge pressure are detected by maintaining 61 at a vacuum and a predetermined gas pressure. In addition, if the pressure case 60 is made of a metal member, it has an effect of reducing high-frequency electromagnetic noise flying from the outside reaching the sensor element 20.
[0049]
An internal space 61 is formed in the pressure case 60, and the internal space 61 is set to a predetermined pressure as shown in FIG. The peripheral portion 62 of the pressure case 60 is hermetically bonded to the insulating protective film 46 made of a glass layer formed on the upper surface of the circuit board 40 with a silicon adhesive 62.
[0050]
In other respects, the gauge pressure type pressure sensor 1 according to the first embodiment has substantially the same configuration.
[0051]
Similarly to the gauge pressure type pressure sensor according to the first embodiment, the pressure sensor 1 having this configuration can also be manufactured without going through a process such as soldering.
[0052]
A configuration of the gauge pressure sensor 1 according to the second embodiment of the present invention will be described with reference to FIGS. FIG. 7 is a longitudinal sectional view showing a configuration of a gauge pressure sensor according to the second embodiment, and FIG. 8 is a bottom view of the connector case.
[0053]
The pressure sensor 1 according to the second embodiment is similar to the gauge pressure type pressure sensor 1 according to the first embodiment shown in FIG. It is characterized by being divided and arranged in a staggered pattern.
[0054]
That is, since the spring-like body 50 connected to the connector 80 is divided into left and right as shown in the figure and is arranged in a staggered manner, when mounting the connector case 70 on the housing 10 with the sensor assembly inserted therein, The connector case 70 is stabilized, and the subsequent caulking process can be performed smoothly.
[0055]
【Effect of the invention】
As described above, according to the present invention, the pressure sensor main body and the connector are connected by the spring-like body having elasticity, and the gauge pressure that can be easily assembled is reduced. A pressure sensor of the type can be provided. Furthermore, an absolute pressure type and shield gauge pressure type pressure sensor can be provided by providing a pressure case inside as required.
[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 bottom view of the connector case of the pressure sensor according to the first embodiment of the present invention.
FIG. 3 is a top view of the pressure sensor holder and the circuit board according to the first embodiment of the present invention.
FIG. 4 is an enlarged cross-sectional view of an electrode pad portion of the pressure sensor according to the first embodiment of the present invention.
FIG. 5 is a longitudinal sectional view showing the structure of a pressure sensor according to a reference example of the present invention.
FIG. 6 is an enlarged cross-sectional view showing a structure of a connection portion of a pressure case of a pressure sensor according to a reference example of the present invention.
FIG. 7 is a longitudinal sectional view showing the structure of a pressure sensor according to a second embodiment of the present invention.
FIG. 8 is a bottom view of a connector case of a pressure sensor according to a second embodiment of the present invention.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Pressure sensor 10 Housing 12 Fluid introduction hole 13 Housing bottom part 14 Annular groove 16 Perimeter wall 17 Caulking part 18 Housing internal space 19 Screw part 20 Sensor element 21 Header 211 Collar part 212 Holder receiving bank 213 Holder upper surface 22 Pressure detection element 23 Base 24 Sensor element opening 25 Bonding wire 30 Holder 31 Holder lower surface 32 Holder opening 33 Positioning cutout 34 Holder upper surface 40 Circuit board 41 Circuit board opening 42 Electrode pad 43 Land portion 44 Printed wiring 45 Circuit element 50 Spring-like body 51 End 52 Bending part 53 Bending part 54 Gold plating part 60 Pressure case 61 Internal space 62 Peripheral part 63 Silicone adhesive 70 Connector case 71 Socket part 72 Internal space 73 Upper peripheral wall 74 Upper peripheral wall lower surface 75 Lower peripheral wall 76 Caulking receiving part 7 positioning portion 78 flat surface 79 connector insertion hole 80 connector 81 connector bottom 95 O-ring 96 O-ring

Claims (3)

A housing having a pressure introducing hole; a pressure detecting element made of a semiconductor element having a piezoresistive effect; a holder for fixing the pressure detecting element via a pedestal and a header; and a connector case; In the pressure sensor as a pressure sensor body in which the holder is hermetically joined via a pedestal and a header to form a reference pressure space, a circuit board having an electrode pad is provided on the holder of the pressure sensor body, A spring-like body having electrical conductivity supported by a connector case and having elasticity;
The spring-like body is disposed in the reference pressure space, one end of which is fixed to the lower end of the connector provided in the connector case, the other end is bent downward, and the tip is formed by a curved portion,
The holder provided with the pressure detecting element and the circuit board is placed on the housing from its inner space, and then the connector case is placed over the housing and inserted into the inner space to be fixed, and the spring A pressure sensor, wherein a curved portion of a cylindrical body is pressed onto the electrode pad.   The pressure sensor according to claim 1, wherein a portion from a portion fixed to a lower end of the connector of the spring-like body to a bent portion is supported by a bottom portion of the internal space of the connector case.   The pressure sensor according to claim 1 or 2, wherein the pressure sensor is a gauge pressure type pressure sensor.

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