JP2001124648A - Pressure measuring device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent the occurrence of an error in the sensor output characteris tic of a pressure measuring device when receiving a fastening force accompanied by the screwing of the pressure measuring device to a part to be measured. SOLUTION: A semiconductor pressure sensor 22 having a connecting pipe 22b and a lead wire 22c is mounted on a first sensor fixing member 23 and a second sensor fixing member 24, and both the sensor fixing members 23, 24 are mutually connected by use of a fastener 25 and fixed to a housing 26 having a projection part 26b on one side of a bottom part 26a and a cylindrical side wall part 26h on the other side of the bottom part. A circuit board 31 is mounted on the first sensor fixing member 24 through a spacer 32 to connect to the lead wire 22c, and a signal line 33 from the circuit board 31 is connected to a connector 30 provided on a housing cap 29. A connecting port 26c for inserting the connecting pipe 22b is provided through the bottom part 26a and projection part 26b, and a screw part 26f is formed on the periphery of the projection part 26b.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a pressure measuring device for detecting a pressure inside a device, for example, a hydraulic pressure inside a transformer.

[0002]

2. Description of the Related Art FIG.
FIG. 7 is a cross-sectional view illustrating a configuration of a conventional pressure measuring device disclosed in Japanese Patent Application Publication No. 7-No. FIG. 15 is a sectional view of a main part of FIG. 14 and 15, 1 is a pressure measuring device, 2 is a semiconductor element that outputs an electric signal according to pressure by a piezoresistance effect, 3 is a lead wire connected to the semiconductor element, 4
Reference symbol a denotes a pressure detection unit formed of a diaphragm that expands and contracts upon receiving a measured pressure, and reference numeral 4b denotes a pressure transmission rod that transmits the pressure received by the pressure detection unit 4a. The semiconductor element 2, the lead wire 3, the pressure detecting section 4a, and the pressure transmitting rod 4b constitute a semiconductor pressure sensor 4. The semiconductor pressure sensor 4 is press-fitted into a front end of a housing 5, and a spacer 6 into which a lead wire 3 is inserted is fitted in the housing 5.
On the outer periphery of the distal end portion 5a of the housing 5 on which the semiconductor pressure sensor 4 is mounted, a screw portion 5c for screwing to the measured pressure portion is formed.

The lead wire 3 penetrates through an insertion hole 6c provided in the spacer 6, and the cover 7 is fitted thereinto.
The lead wire 3 is bent and wired along the groove 6d. The lead wire 3 is bent again by the edge of the cover 7 near the end of the groove 6d, and the taper bush 9 fixed to the amplifier board 8 which is a signal processing circuit board.
And welded by laser irradiation. The output pin 10 fixed to the amplifier board 8 is inserted into the taper bush 14 through the feedthrough capacitor 13 mounted on the plate 12, and is connected to the output lead wire 11. The output lead wire 11 is supported by a support member 15 and is connected to a connector terminal 16. The plate 12 is fixed to the housing 5 by a caulking portion 5d, and covers the opening 5e in which the amplifier board 8 is housed. After the connector terminal 16 is positioned, the connector portion 17 is integrally formed by insert molding.

In the pressure measuring device 1 as described above,
When the pressure to be measured is applied to the pressure detecting section 4a of the semiconductor pressure sensor 4, the pressure is detected by the semiconductor element 2 via the pressure transmitting rod 4b, and the output voltage is input to the amplifier board 8 via the lead wire 3. The voltage amplified by the amplifier board 8 is output from the connector terminal 16.

[0005]

When the pressure to be measured is measured by the pressure measuring device 1 having such a structure, the thread 5c of the housing 5 is screwed to the pressure to be measured. However, at the time of this screwing, the screw portion 5c is reduced in diameter by receiving a tightening force, and when the housing tip 5a is deformed, the deformation also affects the semiconductor pressure sensor 4 via the pressure transmission rod 4b. As a result, there is a problem that an error may occur in the output of the pressure measuring device 1.

When the lead wire 3 penetrates through the insertion opening 6c provided in the spacer 6 and the cover 7 is fitted, the lead wire 3 is bent and wired along the groove 6d. Since the lead wire 3 is bent again by the edge of the cover 7 near the end of 6d, the number of steps required for bending the lead wire 3 increases, and the lead wire 3 is bent.
However, there is a problem that the strength may be lowered due to metal fatigue or the like, or the cut portion may be broken due to metal fatigue.

The pressure measuring device 1 has a housing 5, a spacer 6, a cover 7, a plate 12, and a semiconductor pressure sensor 4 and a signal processing circuit board 8.
A large number of components such as the tapered bushes 9 and 14 and the support member 15 are required, and the assembling becomes complicated, resulting in poor workability. Furthermore, special techniques such as laser welding and insert molding were required.

Further, since the connector portion 17 is integrally formed by insert molding after the positioning of the connector terminal 16, if the necessity of inspection or the like arises, it is impossible to inspect the inside. There was a problem.

Further, since only the amplifier board 8 is mounted inside the pressure measuring device 1, when an offset adjustment, a current conversion, or the like is required, or when a failure diagnosis of the semiconductor pressure sensor 4 is required, In addition, an external circuit BOX including a circuit capable of processing offset adjustment, current conversion, and the like or a failure diagnosis circuit is required separately. Also, a signal line connecting the external circuit BOX and the pressure measuring device 1
There is a problem that an electric noise may enter from outside and cause an error in an output signal.

SUMMARY OF THE INVENTION The present invention has been made to solve the above-described problems, and a first object of the present invention is to provide a pressure measuring apparatus which receives a pressure even when it receives a tightening force caused when a pressure measuring device is screwed to a pressure portion to be measured. An object of the present invention is to provide a pressure measuring device capable of suppressing an error in a sensor output characteristic of the measuring device.

A second object of the present invention is to prevent a reduction in strength or breakage due to metal fatigue of the bent portion even if there is a bent portion associated with the fixing of the lead wire, and a process required for bending the lead wire. An object of the present invention is to provide a pressure measuring device capable of reducing the number.

A third object is to reduce the number of components for mounting the semiconductor pressure sensor and the circuit board to facilitate assembly, and to eliminate the need for special techniques such as laser welding and insert molding. The present invention is to obtain a pressure measuring device which can be operated.

A fourth object of the present invention is to provide a pressure measuring device which can easily inspect the inside even if it has a connector.

A fifth object is to provide a circuit or a circuit capable of processing offset adjustment, current conversion, etc. separately when offset adjustment, current conversion, etc. are required, or when a failure diagnosis of the semiconductor pressure sensor is required. It is not necessary to provide an external circuit BOX having a diagnostic circuit outside the pressure measuring device, and electric noise from outside intrudes into a signal line connecting the external circuit BOX and the pressure measuring device. An object of the present invention is to provide a pressure measuring device capable of suppressing an error in an output signal of the sensor 22.

[0015]

In a pressure measuring apparatus according to the present invention, a semiconductor pressure sensor having a pressure guiding tube and a lead wire; a fixing means for fixing the semiconductor pressure sensor;
A circuit board attached to the fixing means and connected to a lead wire of the semiconductor pressure sensor, and a storage part for storing the semiconductor pressure sensor, the fixing means, and the circuit board, wherein the storage part is provided at a bottom part thereof. A projection is provided on the outside, a pressure guide port is provided in the projection to insert a pressure guide tube of the semiconductor pressure sensor, and a screw portion is formed on the outer periphery of the projection.

Further, a cup-shaped housing having a projection on one side of the bottom and a cylindrical side wall on the other side of the bottom, and fixing means provided in contact with the bottom in the side wall of the housing. A semiconductor pressure sensor provided in a fixing means and having a pressure sensor chip housed in a package portion having a pressure guiding tube and a lead wire; and a circuit provided in a side wall portion of a housing and connected to a lead wire of the semiconductor pressure sensor. And a housing cap having a connector connected to a signal line from the circuit board, wherein the fixing means comprises a first insertion opening into which a package portion of the semiconductor pressure sensor is inserted and a lead wire. And a second sensor fixing member having a third insertion port into which the pressure guiding tube of the semiconductor pressure sensor is inserted. , The housing bottom and electrical pressure port which impulse line of the semiconductor pressure sensor is inserted into the protruding portion 3
Are provided coaxially with the through-holes, and a screw portion is formed on the outer periphery of the projection.

Further, a cup-shaped housing having a projection on one side of the bottom and a cylindrical side wall on the other side of the bottom, and fixing means provided in contact with the bottom in the side wall of the housing. And a semiconductor pressure sensor provided in the fixing means and containing the pressure sensor chip in a package portion having a pressure guiding tube and a lead wire, and provided in a side wall portion of the housing, and a lead wire from the semiconductor pressure sensor forms a lead frame. And a housing cap having a connector connected to a signal line from the circuit board, wherein the fixing means is a first member into which a package portion of the semiconductor pressure sensor is inserted. A first sensor fixing member having a second insertion port into which a lead frame is inserted and a third insertion port into which a pressure guiding tube of a semiconductor pressure sensor is inserted. And a second sensor fixing member for fixing the lead frame, wherein the housing is provided with a pressure guiding port for inserting the pressure guiding tube of the semiconductor pressure sensor at the bottom and the projection coaxially with the third insertion port. Is formed with a threaded portion on the outer periphery.

Further, a cup-shaped housing having a projection on one side of the bottom and a cylindrical side wall on the other side of the bottom, and fixing means provided in contact with the bottom in the side wall of the housing. And a semiconductor pressure sensor provided in the fixing means and containing the pressure sensor chip in a package portion having a pressure guiding tube and a lead wire, and provided in a side wall portion of the housing, and a lead wire from the semiconductor pressure sensor forms a lead frame. And a housing cap having a connector connected to a signal line from the circuit board, wherein the fixing means is a first member into which a package portion of the semiconductor pressure sensor is inserted. A first sensor fixing member having a through hole and a second through hole into which a lead frame is inserted, a first sensor fixing member having a cylindrical portion protruding along a side wall portion of the housing, and a semiconductor. The impulse line of the force sensor is inserted 3
And a second sensor fixing member for fixing the lead frame. The housing has a pressure guiding port, into which the pressure guiding tube of the semiconductor pressure sensor is inserted into the bottom and the projection, as the third insertion port. It is provided coaxially and has a screw portion formed on the outer periphery of the projection.

Further, the lead frame is fixed to the second sensor fixing member so as to be connected to the lead wire from the semiconductor pressure sensor and the circuit board.

Further, the circuit board includes a first board including a sensor drive circuit and a temperature compensation circuit, a second board including an amplifier for amplifying sensor output and an offset adjusting circuit, a current conversion for sensor output, or A third substrate comprising a digital conversion circuit.

Further, the circuit board is detachably provided.

Further, the circuit board has a diagnostic circuit for performing a self-diagnosis of the semiconductor pressure sensor.

Further, the connector is detachably provided on the housing cap.

[0024]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiment 1 FIG. 1 is a sectional view showing a configuration of a pressure measuring device according to Embodiment 1 of the present invention,
FIG. 2 is a cross-sectional view showing the mounting of the semiconductor pressure sensor, and FIG.
3 is a plan view of the first sensor fixing member of FIG. 1, FIG. 3B is a cross-sectional view taken along line IIIb-IIIb of FIG. 3A, and FIG. 4A is a second view of FIG. FIG. 4B is a plan view of the sensor fixing member, and FIG. 4B is a side view of FIG.

1, 2, 3 (a), 3 (b), 4 (a), and 4 (b), reference numeral 21 denotes a pressure measuring device;
Reference numeral 22 denotes a semiconductor pressure sensor, which is a package unit 22 having a pressure guiding tube 22b having a pressure guiding port 22a and a lead wire 22c.
The pressure sensor chip 22e is housed in d. The package portion 22d includes a cap 22g made of a metal having a peripheral portion 22f and a base 22i made of a metal having a pressure guiding port 22h.
i are joined. A pressure guiding tube 22b is joined below the base 22i coaxially with the pressure introducing port 22h, and a pedestal 22k made of glass or the like having a pressure guiding port 22j is joined above the base 22i. The pressure sensor chip 22e is joined thereon. For this reason, the pressure introduction ports 22a, 22h, and 22j communicate with the back side of the pressure sensor chip 22e.

Reference numerals 23 and 24 denote fixing means for fixing the semiconductor pressure sensor 22. The PPS has insulating properties and heat resistance.
A first sensor fixing member 23 made of a resin material such as (Poly Phenylene Sulfide);
And a second sensor fixing member 24 made of a resin material such as The first sensor fixing member 23 is connected to the first insertion opening 23a into which the package portion 22d of the semiconductor pressure sensor 22 is inserted, the second insertion opening 23b into which the lead wire 22c is inserted, and the second sensor fixing member 24. And a female screw 23c into which the fastening tool 25 is screwed. The second sensor fixing member 24 has a projection 24b having an insertion opening 24a into which the pressure guiding tube 22b is inserted, and the insertion opening 2 into which the pressure guiding tube 22b is inserted by being in contact with the other housing.
4a and a pad portion 24e having a female screw 24d into which the fastening tool 25 is screwed.

Reference numeral 26 denotes a cup-shaped housing made of metal, which has a projection 26b on one side of a bottom 26a and a cylindrical side wall 26h on the other side of the bottom 26a. A pressure guiding port 26c into which the pressure guiding tube 22b of the semiconductor pressure sensor 22 is inserted is provided on the bottom 26a and the protrusion 26b of the housing 26 coaxially with the insertion port 24a of the second sensor fixing member 24. Further, a counterbore portion 26d is provided, into which an O-ring 27 which is compressed to the side surface of the pressure guiding tube 22b and the bottom surface of the second sensor fixing member 24 and is provided so as to be in contact with the side surface and the bottom surface is inserted. Further, a female screw 26e for screwing the fastening tool 25 to the bottom portion 26a and a protrusion 26
A screw portion 26f is formed on the outer periphery of b. Side wall 26
A screw portion 26g for screwing a housing cap to be described later is formed on the upper part of h. The O-ring 27 is compressed by the bottom of the second sensor fixing member 24 in the axial direction of the pressure guiding tube 22b and extends in the vertical direction, filling the gap between the pressure guiding tube 22b and the housing 26.

Reference numeral 29 denotes a housing cap made of metal which is screwed to the screw portion 26g of the housing 26, and has a detachable connector 30. Reference numeral 31 denotes a circuit board on which a driving circuit for the semiconductor pressure sensor 22 and a signal processing circuit for processing a pressure signal from the semiconductor pressure sensor 22 are formed. The first sensor fixing member 23 is provided via a spacer 32 with a screw.
Attached to. One of the circuit boards 31 is connected to a lead wire 22 c from the semiconductor pressure sensor 22, and the other is connected to the connector 30 via a signal line 33.
When offset adjustment, current conversion, A / D conversion, or the like is required, or when a failure diagnosis of the semiconductor pressure sensor is required, an external circuit BOX (not shown) is separately connected to the pressure measurement device 21 via the connector 30. It is provided outside.

Next, a method of assembling the pressure measuring device 21 will be described. First, the pressure guide tube 22b of the semiconductor pressure sensor 22 is connected to the insertion port 24a of the second sensor fixing member 24.
Insert Thereafter, the lead wire 22c is bent upward and inserted into the insertion opening 23b of the first sensor fixing member 23 while the package portion 22d of the semiconductor pressure sensor 22 is
Is inserted into the insertion opening 23a of the first sensor fixing member 23. The size of the insertion port 23a is larger than the outer circumference of the package portion 22d and smaller than the outer circumference of the base 22i.
Only the package portion 22d is inserted, and the peripheral portion 22f and the lower corner portion of the insertion opening 23a come into contact with each other, and positioning is performed in that state. At this time, the axes of the female screw 23c of the first sensor fixing member 23 and the female screw 24d of the second sensor fixing member 24 are aligned with each other. The fixing member 23 and the second sensor fixing member 24 are connected to fix the semiconductor pressure sensor 22.

Next, with the semiconductor pressure sensor 22 fixed to both sensor fixing members 23 and 24, the housing 26
Then, a female screw 26e formed in the housing 26 is aligned and screwed, and the sensor fixing members 23 and 24 are fixed to the housing 26. At this time, the O-ring 27 is inserted into the counterbore portion 26d of the housing 26. The O-ring 27 is compressed by the bottom surface of the second sensor fixing member 24 in a direction parallel to the axial direction of the pressure guiding tube 22b and extends in a vertical direction, and fills a gap between the pressure guiding tube 22b and the housing 26. .

Next, the circuit board 31 on which the drive circuit and the signal processing circuit of the semiconductor pressure sensor 22 are formed is fixed to the first sensor fixing member 23 via the spacer 32 with a screw. Male threads are formed at both ends of the threaded spacer 32. Further, a female screw is formed on the head of the fastener 25, and the male screw of the spacer 32 is screwed into the spacer 32 to erect the spacer 32, and the other male screw is inserted into a mounting hole 31a formed in the circuit board 31. Then, the circuit board 31 is fixed by tightening the circuit board 31 from above with a nut or the like.

At this time, the lead wire 22c protruding toward the circuit board 31 through the insertion opening 23b of the first sensor fixing member 23 is soldered to a predetermined position on the circuit board 31. The contact holes of the circuit board 31 can be soldered from both sides.
1 and is soldered on the substrate surface side. Thereafter, the signal line 33 protruding from the circuit board 31 is soldered to the detachable connector 30, the housing cap 29 is screwed to the screw portion 26g of the housing 26, and finally the connector 30 is screwed to the housing cap 29. Fix it.

In the pressure measuring device 21 as described above, the pressure to be measured due to the abnormality in the portion to be measured passes through the pressure guiding port 26c of the housing 26 and the pressure guiding port 22a of the pressure guiding tube 22b of the semiconductor pressure sensor 22. , Pressure sensor chip 22
e, the output voltage is input to the circuit board 31 via the lead wire 22c, and the voltage amplified by the circuit board 31 is output from the connector 30 via the signal line 33.

According to the pressure measuring device 21 of the first embodiment, the first insertion opening 23a into which the package portion 22d of the semiconductor pressure sensor 22 is inserted and the second insertion opening 23b into which the lead wire 22c is inserted. And a second sensor fixing member 24 having a third insertion opening 24a into which the pressure guiding tube 22b of the semiconductor pressure sensor 22 is inserted. The housing 26 includes a bottom 26a and a protrusion. 26b is a pressure guiding tube 22b of the semiconductor pressure sensor 22.
Is formed coaxially with the third insertion port 24a, and a screw portion 26f is formed on the outer periphery of the protrusion 26b, so that the measured pressure portion is screwed to the screw portion 26. Since the pressure of the portion to be measured is transmitted to the semiconductor sensor chip 22e through the pressure guiding port 22a inside the pressure guiding tube 22b part of which is inserted into the pressure guiding port 26c, the screw portion 26f
Therefore, it is possible to prevent the influence of distortion or diameter reduction due to screw tightening from being directly transmitted to the semiconductor sensor chip 22e, and thus it is possible to suppress the occurrence of errors in the output of the pressure measuring device 21.

The semiconductor pressure sensor 22 is also provided with the cap 2.
The 2g peripheral portion 22f and the base 22i are pressed down and fixed by the base 22i, so that the structure is hardly affected by lateral distortion due to screwing of the screw portion 26f. For this reason, it is possible to suppress an error that occurs when the pressure measuring device 21 is attached to the portion to be measured, or a deterioration with time of the sensor output characteristic due to a long-term tightening force.

The components for mounting the semiconductor pressure sensor 22 and the circuit board 31 include a first sensor fixing member 23, a second sensor fixing member 24, and a fastener 2.
(5) It is possible to use the parts of the spacer 32 with a thread, so that the number of components for assembling can be remarkably reduced as compared with the conventional example, and the assembling is also simple. Further, since the components are joined by screwing or soldering, special techniques such as laser welding and insert molding as in the conventional example can be omitted.

Further, by forming the first sensor fixing member 23 and the second sensor fixing member 24 from an insulating and heat-resistant material such as PPS, deformation and destruction due to a temperature change are prevented, and the semiconductor pressure is reduced. The electric insulation between the sensor 22 and the housing 26 is strengthened, so that the influence of external electric noise or the like can be prevented.

The signal line 3 extending from the circuit board 32
Since the connector 3 is connected to the detachable connector 30, it is possible to easily inspect the inside.

Embodiment 2 FIG. 5 is a sectional view showing a configuration of a pressure measuring device according to Embodiment 2 of the present invention, FIG. 6 (a) is a plan view showing a main part of FIG. 5, and FIG. 6 (b) is a side view of FIG. FIG. In FIGS. 5, 6 (a) and 6 (b), FIGS. 1, 2, 3 (a), 3 (b), 4
4A and 4B denote the same or equivalent parts, and a description thereof will be omitted.

Reference numeral 41 denotes a pressure measuring device, and reference numeral 42 denotes a lead frame which is made of a conductive material such as copper or aluminum and which is bent perpendicularly to a second sensor fixing member 44 described later.
One is embedded in the second sensor fixing member 44 by molding, and the semiconductor pressure sensor 2
The other, which is connected to the second lead wire 22c and is bent vertically, extends upward, passes through an insertion opening of a first sensor fixing member 43 described later, and has a thin end so that it can be inserted into a contact hole of the circuit board 31. Connected to the circuit board 31.

Reference numerals 43 and 44 denote fixing means for fixing the semiconductor pressure sensor 22. A first sensor fixing member 43 made of a resin material such as PPS and a second means made of a resin material such as PPS.
And a sensor fixing member 44. The first sensor fixing member 43 includes a first insertion opening 43a into which the package portion 22d of the semiconductor pressure sensor 22 is inserted, a second insertion opening 43b into which the lead frame 42 is inserted, and a second insertion opening 43b.
And a female screw 43c for screwing the fastening member 25 for connection of the sensor fixing member 44. Second sensor fixing member 44
Is a projection 44b having an insertion port 44a which is in contact with the lower side of the base 22i and into which the pressure guiding tube 22b is inserted, and an insertion port 44a which is in contact with the housing described later and in which the pressure guiding tube 22b is inserted. A pad portion 4 having a female screw 44d for screwing the fastener 25 and a concave portion 44e in which the lead frame 42 connected to the lead wire 22c is embedded.
4f, and the projection 44b and the pad 44f are joined.

Next, a method of assembling the pressure measuring device 41 according to the second embodiment will be described. First, the pressure guide tube 22b of the semiconductor pressure sensor 22 is connected to the lead frame 42.
Is fixed to the concave portion 44e.
4 into the insertion opening 44a. The semiconductor pressure sensor 22 is set so that the lead wire 22c contacts the lead frame 42.
And the lead wire 22c is connected to the lead frame 42.
Solder to one end and cut off excess length. The package portion 22d is inserted into the insertion opening 43a of the first sensor fixing member 43 while inserting the lead frame 42 into the insertion opening 43b of the first sensor fixing member 43.

The size of the insertion port 43a is
d, and is smaller than the outer periphery of the base 22i. Therefore, only the package portion 22d of the semiconductor pressure sensor 22 is inserted into the insertion port 43a, and the outer peripheral portion 2 is formed.
The lower corner of the insertion opening 43a comes into contact with 2f and the positioning is performed in that state. At this time, the female screw 43c of the first sensor fixing member 43 and the female screw 44 of the second sensor fixing member 44
d is aligned with the axis, and the fastener 2
5 is used to couple the first sensor fixing member 43 and the second sensor fixing member 44 to fix the semiconductor pressure sensor 22.

Thereafter, assembly is performed in the same manner as in the first embodiment.

In the pressure measuring device 41 as described above, the pressure to be measured due to the abnormality in the portion to be measured is supplied via the pressure guiding port 26c of the housing 26 and the pressure guiding port 22a of the pressure guiding tube 22b of the semiconductor pressure sensor 22. , Pressure sensor chip 22
e, the output voltage is input to the circuit board 31 via the lead wire 22c, and the voltage amplified by the circuit board 31 is output from the connector 30 via the signal line 33.

According to the pressure measuring device 41 of the second embodiment, the first insertion port 43a into which the package portion 22d of the semiconductor pressure sensor 22 is inserted and the lead frame 42
A first sensor fixing member 43 having a second insertion hole 43b into which the pressure sensor is inserted, and a pressure guiding tube 22b of the semiconductor pressure sensor 22.
A third sensor fixing member 44 for fixing the lead frame 42, the third sensor fixing member 44 for fixing the lead frame 42,
The housing 26 is provided with a pressure guiding port 26c in which the pressure guiding tube 22b of the semiconductor pressure sensor 22 is inserted into the bottom 26a and the projection 26b coaxially with the third insertion port 24a.
By forming the screw portion 26f on the outer circumference of the screw b, the pressure portion to be measured is screwed to the screw portion 26. Therefore, the pressure of the portion to be measured is increased by the pressure guiding tube partially inserted into the pressure guiding port 26c. Since the light is transmitted to the semiconductor sensor chip 22e through the pressure guiding port 22a inside the semiconductor sensor chip 22e, it is possible to prevent the influence of distortion or diameter reduction due to the screwing of the screw portion 26f from being directly transmitted to the semiconductor sensor chip 22e. It is possible to suppress the occurrence of an error in the output of.

The semiconductor pressure sensor 22 is also provided with the cap 2
The 2g peripheral portion 22f and the base 22i are pressed down and fixed by the base 22i, so that the structure is hardly affected by lateral distortion due to screwing of the screw portion 26f. For this reason, it is possible to suppress an error occurring when the pressure measuring device 41 is attached to the measurement target portion, or a deterioration with time of the sensor output characteristic due to a tightening force applied for a long time.

The lead frame 42 bent perpendicularly to the second sensor fixing member 44 is connected to the lead wire 22c from the semiconductor pressure sensor 22 and the circuit board. Therefore, the lead wire 22 does not need to be bent, so that the number of steps required for bending is reduced, and it is possible to prevent a reduction in strength due to metal fatigue of a bent portion, a breakage of the lead wire 22, and the like.

The components for mounting the semiconductor pressure sensor 22 and the circuit board 31 include a first sensor fixing member 43, a second sensor fixing member 44, and a fastener 2.
5, it is possible to use the parts of the threaded spacer 32 and the lead frame 42, so that the number of components for assembling can be remarkably reduced as compared with the conventional example, and the assembling is also easy. Furthermore, since the connection between parts is performed by screwing or soldering,
Special techniques such as laser welding and insert molding as in the conventional example can be made unnecessary.

Further, by forming the first sensor fixing member 43 and the second sensor fixing member 44 from an insulating and heat-resistant material such as PPS, deformation and destruction due to a temperature change are prevented, and the semiconductor pressure is reduced. The electric insulation between the sensor 22 and the housing 26 is strengthened, so that the influence of external electric noise or the like can be prevented.

The signal line 3 extending from the circuit board 32
Since the connector 3 is connected to the detachable connector 30, it is possible to easily inspect the inside.

Embodiment 3 FIG. FIG. 7 is a sectional view showing a configuration of a pressure measuring device according to Embodiment 3 of the present invention, and FIG.
8 is a plan view of the first sensor fixing member of FIG. 7, and FIG. 8B is a cross-sectional view taken along line VIIIb-VIIIb of FIG. 8A. 7, 8 (a) and 8 (b), the same reference numerals as those in the second embodiment of the present invention denote the same or equivalent parts, and a description thereof will be omitted.

Reference numeral 51 denotes a pressure measuring device, and reference numerals 53 and 54 denote fixing means for fixing the semiconductor pressure sensor 22. The fixing means comprises a first sensor fixing member 53 made of a resin material such as PPS and a second sensor fixing member 54. Is done. The first sensor fixing member 53 is connected to the package 22 d of the semiconductor pressure sensor 22.
A first insertion hole 53a into which the lead frame 42 is inserted, a second insertion hole 53b into which the lead frame 42 is inserted, and a female screw 53c into which the second sensor fixing member 54 connecting fastener 55 is screwed. Further, the first sensor fixing member 53
Is a cylindrical portion 53d that comes into contact with the inner periphery of a cylindrical side wall portion 56h of the housing 56 described later and protrudes at the same height as the side wall portion 56h.
Having.

The second sensor fixing member 54 is
i, a projection 54b having an insertion opening 54a into which the pressure guiding tube 22b is inserted, and an insertion opening 5 into which the pressure guiding tube 22b is inserted, which is in contact with a housing 56 described later.
4a and a female screw 5 at a stop for screwing the fastening tool 25
4d and a pad portion 54f having a concave portion 54e in which the lead frame 42 connected to the lead wire 22c is embedded by molding. Reference numeral 57 denotes an annular packing, which is attached between the housing cap 29 and the cylindrical portion 53d and the side wall portion 56h.

Reference numeral 56 denotes a cup-shaped housing made of metal having a projection 56b on one side of a bottom 56a and a cylindrical side wall 56h on the other side of the bottom 56a. A pressure guiding port 56c into which the pressure guiding tube 22b of the semiconductor pressure sensor 22 is inserted is provided on the bottom 56a and the projection 56b of the housing 56 coaxially with the insertion port 54a of the second sensor fixing member 54. And a counterbore portion 56d into which the O-ring 27 provided to be compressed and in contact with the side surface of the second sensor fixing member 54 is provided. Further, a screw portion 56e is formed on the outer periphery of the protrusion 56b, and a screw portion 56f for screwing the housing cap 29 is formed on the upper portion of the side wall portion 56h.

Next, a method of assembling the pressure measuring device 51 according to the third embodiment will be described. First, the pressure guide tube 22b of the semiconductor pressure sensor 22 is connected to the lead frame 42.
Is fixed to the insertion opening 5 of the second sensor fixing member 54.
4a. The lead wire 22c is a lead frame 42
The semiconductor pressure sensor 22 is positioned so as to come into contact with the lead frame, the lead wire 22c is soldered to one end of the lead frame 42, and an extra length is cut. The package portion 22d is inserted into the insertion port 53a of the first sensor fixing member 53 while inserting the lead frame 42 into the insertion port 53b of the first sensor fixing member 53.

The size of the insertion port 53a is
d, it is formed smaller than the outer circumference of the base 22i, so that only the package portion 22d of the semiconductor pressure sensor 22 is inserted into the insertion port 53a, and
The lower corner of the insertion opening 53a comes into contact with 2f, and the positioning is performed in that state. At this time, the female screw 53c of the first sensor fixing member 53 and the female screw 54 of the second sensor fixing member 54
d is aligned with the axis, and the fastening tool 5
5 is used to couple the first sensor fixing member 53 and the second sensor fixing member 54 to fix the semiconductor pressure sensor 22.

Next, with the semiconductor pressure sensor 22 fixed to the sensor fixing members 53 and 54, the housing 56
Insert At this time, the counterbore portion 56 of the housing 56
The O-ring 27 is inserted in d. O-ring 27 is the first
Is compressed in the direction parallel to the axial direction of the pressure guiding tube 22b and expanded in the vertical direction by the bottom surface of the sensor fixing member 53, thereby filling the gap between the pressure guiding tube 22b and the housing 56.

Next, the circuit board 31 on which the drive circuit and the signal processing circuit of the semiconductor pressure sensor 22 are formed is fixed to the first sensor fixing member 53 via the spacer 32 with a screw. Male threads are formed at both ends of the threaded spacer 32. Further, a female screw is formed on the head of the fastening tool 55, and the male screw of the spacer 32 is screwed into the spacer 32 to erect the spacer 32, and the other male screw is connected to the circuit board 3.
1 into the mounting hole 31a formed in the circuit board 3
The circuit board 31 is fixed by clamping the circuit board 31 from above with a nut or the like.

At this time, the lead frame 42 protruding toward the circuit board through the insertion opening 53b of the first sensor fixing member 53 is soldered to a predetermined position on the circuit board 31. The contact holes of the circuit board 31 can be soldered from both sides. The lead frame 42 is penetrated to the surface of the circuit board 31 and soldered on the board surface side.
Thereafter, the signal line 33 protruding from the circuit board 31 is soldered to the detachable connector 30 and the housing cap 2
9 through a packing 57 to a screw portion 56 of a housing 56.
Then, the connector 30 is screwed and fixed to the housing cap 29 at last.

In the pressure measuring device 51 as described above, the pressure to be measured due to the abnormality in the measured portion passes through the pressure guiding port 56c of the housing 56 and the pressure guiding port 22a of the pressure guiding tube 22b of the semiconductor pressure sensor 22. , Pressure sensor chip 22
e, the output voltage is input to the circuit board 31 via the lead wire 22c and the lead frame 42, and the voltage amplified by the circuit board 31 is output from the connector 30 via the signal line 33.

According to the pressure measuring device 51 of the third embodiment, the same functions and effects as those of the second embodiment can be obtained by having the same components as those of the second embodiment.

Further, the first sensor fixing member 53 has a cylindrical portion 53 protruding along the side wall portion 56h of the housing 56.
d, the circuit board 31, the lead frame 42,
The signal line 33 can be prevented from directly contacting the housing 56. For this reason, it is possible to suppress the occurrence of an error in the output signal of the semiconductor pressure sensor 22 due to the intrusion of electric noise from outside the housing 56.

Since the fixing of the sensor fixing members 53 and 54 and the housing 56 is performed by using the tightening force of the housing cap 29 via the packing 57, the sensor fixing members 53 and 54 are fixed to the housing 56. The work of providing a female screw becomes unnecessary, and the screw tightening work of this portion is also unnecessary, so that the number of work steps can be reduced. Also, by simply removing the housing cap 29, the contents can be taken out of the housing 56,
Replacement of the O-ring 27 and inspection of the inside can be performed more easily.

Embodiment 4 FIG. 9 is a sectional view showing a configuration of a pressure measuring device according to a fourth embodiment of the present invention, and FIG.
3 is a block circuit diagram of FIG. 9 and 10, the same reference numerals as those in the third embodiment of the present invention denote the same or equivalent parts, and a description thereof will be omitted.

Reference numeral 61 denotes a pressure measuring device; 62a, a first circuit board for driving the semiconductor pressure sensor 22 and temperature compensation; 62b, a second circuit board for amplifying and offset-adjusting the sensor output; and 62c, a sensor output. It is a third circuit board that performs current conversion or digital conversion. Each of the circuit boards 62a, 62b, 62c is connected and fixed by a threaded spacer 63 which is easily removable. The threaded portion of the threaded spacer 63 may be formed of an electrically conductive material such as copper or aluminum, and the fixing of the circuit board and the electrical connection may be performed simultaneously.

Next, the operation of these circuit boards will be described. The first circuit board 62a supplies a power supply voltage Vb necessary for driving the semiconductor pressure sensor 22. When pressure is applied to the pressure sensor chip 22e of the semiconductor pressure sensor 22, a voltage V1 corresponding to the pressure is output. This output voltage V
Since 1 slightly changes depending on the ambient temperature, temperature compensation is performed by the first circuit board 62a, and a voltage V2 independent of temperature is output. This output voltage V2 is input to the second circuit board 62b, and a voltage V3 to which an offset voltage has been applied and amplified is output. There is no problem if this output voltage V3 is used as an output as it is. However, an ordinary measuring instrument generally outputs a current of, for example, 4 to 20 mA, and converts the output voltage V3 into a current output I1 by using a third circuit board 62c so as to correspond to the measuring instrument. Both V3 and current output I1 can be output. Also, a circuit for converting the output voltage V3 into a digital signal and converting the digital signal to an output voltage V4 is provided on the third circuit board 62c so that the output signal can be input to the microcomputer and subjected to digital processing or the like. I have.

According to the pressure measuring device 61 of the fourth embodiment, the same functions and effects as those of the third embodiment can be obtained by having the same components as those of the third embodiment.

Further, since the circuit boards 62a, 62b and 62c for executing the above-described processing are accommodated in the pressure measuring device 61, an external circuit BOX necessary for offset adjustment, current conversion, and the like is provided outside the pressure measuring device. It is not necessary to provide the semiconductor pressure sensor 22, and it is possible to suppress the occurrence of an error in the output signal of the semiconductor pressure sensor 22 due to external electric noise entering the signal line connecting the external circuit BOX and the pressure measuring device. .

Further, since the connection signal line between the semiconductor pressure sensor 22 and the circuit board can be shortened, it is effective in reducing noise. Furthermore, since the circuit boards are fixed to each other by the easily attachable / detachable spacer 63 with screws, the inside can be easily inspected.

In order to fix the circuit boards 62a, 62b and 62c, instead of the easily attachable / detachable threaded spacer 63, FIG. 11 (a cross-sectional view showing the structure of another pressure measuring device of the fourth embodiment), The configuration shown in FIG. 12 (an explanatory view of the main part of FIG. 11) may be adopted, and the same operation and effect as those of the fourth embodiment are obtained. That is, in FIGS. 11 and 12, reference numeral 64 denotes a spring-type insert pin for fixing the circuit boards 62a, 62b, and 62c.
b. When the spring-type insert pin 64 is provided, a convex portion 53e is formed on the cylindrical portion 53d so that the spring portion 64a is fixed to the cylindrical portion 53d. Circuit board 6
Insert pin 64 sandwiching 2a, 62b, 62c
By pushing b into the convex portion 53e, the circuit board can be fixed. Also, it can be easily removed by pulling it in the opposite direction. For this reason, the internal inspection can be easily performed.

Embodiment 5 FIG. 13 is a block circuit diagram of a pressure measuring device according to Embodiment 5 of the present invention. FIG.
, The same reference numerals as those in Embodiment 4 of the present invention denote the same or equivalent parts, and a description thereof will be omitted.

Reference numeral 71 denotes a pressure measuring device, and reference numeral 72 denotes a failure diagnosis circuit provided in the pressure measuring device 71. The failure diagnosis circuit 72 includes a drive circuit for the semiconductor pressure sensor 22 and a signal processing circuit. By the failure diagnosis circuit 72,
A signal for failure diagnosis is input to the semiconductor pressure sensor 22. If the semiconductor pressure sensor 22 is normal, a predetermined output is output to the connector 30 via the signal line 33. However, if there is any abnormality in the semiconductor pressure sensor 22, a predetermined output cannot be obtained. With this configuration, when a failure diagnosis of the semiconductor pressure sensor 22 is required, an external circuit BOX including a failure diagnosis circuit can be unnecessary. The input signal for failure diagnosis of the failure diagnosis circuit 72 may be a voltage or a current. In addition, a circuit configuration may be used in which all output signals other than a predetermined output are regarded as abnormal.

[0074]

Since the present invention is configured as described above, it has the following effects.

A semiconductor pressure sensor having a pressure guide tube is provided with a projection outside the bottom of the storage portion, and a pressure guide port into which the pressure guide tube of the semiconductor pressure sensor is inserted is provided on the projection, and an outer periphery of the projection is provided. Since the pressure of the measured part screwed to the screw portion is transmitted to the semiconductor pressure sensor through the pressure guiding tube of the semiconductor pressure sensor inserted into the pressure introducing port, the screw portion is formed in the screw portion. It is possible to prevent the influence of distortion or diameter reduction due to screw tightening from being directly transmitted to the semiconductor sensor, and thus it is possible to suppress an error in the output of the pressure measuring device.

A semiconductor pressure sensor in which a pressure sensor chip is housed in a package having a pressure guiding tube, a first sensor fixing member having a first insertion opening into which the package of the semiconductor pressure sensor is inserted, and a semiconductor A second sensor fixing member having a third through hole into which the pressure guiding tube of the pressure sensor is inserted, and a pressure guiding member into which the pressure guiding tube of the semiconductor pressure sensor is inserted into the bottom and the projection of the housing having the projection at the bottom. By providing the port coaxially with the third insertion port and forming a screw portion on the outer periphery of the protrusion, the pressure of the measured portion screwed to the screw portion passes through the pressure guiding tube inserted into the pressure guiding port. Since the power is transmitted to the semiconductor sensor chip, it is possible to prevent the influence of distortion or diameter reduction due to the tightening of the screw portion from directly transmitting to the semiconductor sensor chip, thereby suppressing an error in the output of the pressure measuring device. Rukoto is possible.

The components for mounting the semiconductor pressure sensor and the like can be the first sensor fixing member, the second sensor fixing member, and the like. It can be reduced and the assembly can be simplified. In addition, since the components are joined by screwing or soldering, special techniques such as laser welding and insert molding as in the conventional example can be omitted.

A semiconductor pressure sensor in which a pressure sensor chip is housed in a package having a pressure guiding tube, a first sensor fixing member having a first insertion port into which the package of the semiconductor pressure sensor is inserted, and a semiconductor A second sensor fixing member having a third through hole into which the pressure guiding tube of the pressure sensor is inserted, and a pressure guiding member into which the pressure guiding tube of the semiconductor pressure sensor is inserted into the bottom and the projection of the housing having the projection at the bottom. By providing the port coaxially with the third insertion port and forming a screw portion on the outer periphery of the protrusion, the pressure of the measured portion screwed to the screw portion passes through the pressure guiding tube inserted into the pressure guiding port. Since the power is transmitted to the semiconductor sensor chip, it is possible to prevent the influence of distortion or diameter reduction due to the tightening of the screw portion from directly transmitting to the semiconductor sensor chip, thereby suppressing an error in the output of the pressure measuring device. Rukoto is possible.

A cup-shaped housing having a projection on one side of the bottom and a cylindrical side wall on the other side of the bottom, and a semiconductor having a pressure sensor chip housed in a package having a pressure guiding tube. A pressure sensor, a first sensor fixing member having a cylindrical portion protruding along a side wall of the housing, and having a first insertion opening into which a package portion of the semiconductor pressure sensor is inserted, and a pressure guiding tube of the semiconductor pressure sensor And a housing cap having a connector connected to a signal line from a circuit board, and a semiconductor pressure sensor of a semiconductor pressure sensor is provided on the bottom and the protrusion of the housing. By providing a pressure guiding port into which the pressure guiding tube is inserted coaxially with the third insertion port, and forming a screw portion on the outer periphery of the protrusion, the pressure of the measured portion screwed to the screw portion is reduced.
Since the power is transmitted to the semiconductor sensor chip through the pressure guiding tube inserted into the pressure guiding port, it is possible to prevent the influence of distortion or diameter reduction due to the tightening of the screw portion from being directly transmitted to the semiconductor sensor chip. It is possible to prevent an error from occurring in the output. Further, the first sensor fixing member includes a cylindrical portion 53d protruding along the side wall of the housing.
Can prevent the circuit board, the lead frame, and the signal line from coming into direct contact with the housing, so that electric noise can enter from outside the housing and cause an error in the output signal of the semiconductor pressure sensor. Can be suppressed.

Since the lead frame is fixed to the second sensor fixing member so as to be connected to the lead wire from the second sensor fixing member semiconductor pressure sensor and the circuit board, it is not necessary to bend the lead wire. In addition to reducing the number of steps required for bending, it is possible to prevent a reduction in strength due to metal fatigue or the like in a bent portion, breakage of a lead wire, and the like.

The circuit board includes a first board including a sensor driving circuit and a temperature compensation circuit, a second board including a sensor output amplifying and offset adjusting circuit, a current converting sensor output, or The provision of the third substrate composed of a digital conversion circuit makes it unnecessary to provide an external circuit BOX required for offset adjustment, current conversion, and the like outside the pressure measurement device. It is possible to suppress the occurrence of an error in the output signal of the semiconductor pressure sensor due to the intrusion of electric noise from the outside into the signal line connecting

Further, since the circuit board is detachably provided, the inside can be easily inspected.

Further, the circuit board is provided with a diagnostic circuit for self-diagnosis of the semiconductor pressure sensor. When a failure diagnosis of the semiconductor pressure sensor is required, an external circuit BOX having a failure diagnosis circuit is separately provided. Can be eliminated.

Further, since the connector is detachably provided on the housing cap, the inside can be easily inspected.

[Brief description of the drawings]

FIG. 1 is a sectional view showing a configuration of a pressure measuring device according to a first embodiment of the present invention.

FIG. 2 is a sectional view showing how a semiconductor pressure sensor is mounted.

3 (a) is a plan view of a first sensor fixing member of FIG. 1, and FIG. 3 (b) is an arrow IIIb-II of FIG. 3 (a).
It is sectional drawing seen from the Ib line.

FIG. 4A is a plan view of the second sensor fixing member of FIG. 1, and FIG. 4B is a side view of FIG. 4A.

FIG. 5 is a sectional view showing a configuration of a pressure measuring device according to a second embodiment of the present invention.

6A is a plan view showing a main part of FIG. 5, and FIG.
FIG. 6B is a side view of FIG.

FIG. 7 is a sectional view showing a configuration of a pressure measuring device according to a third embodiment of the present invention.

8 (a) is a plan view of the first sensor fixing member of FIG. 7, and FIG. 8 (b) is a view VIIIb-V of FIG. 8 (a).
It is sectional drawing seen from the IIIb line.

FIG. 9 is a sectional view showing a configuration of a pressure measuring device according to a fourth embodiment of the present invention.

FIG. 10 is a block circuit diagram of FIG. 9;

FIG. 11 is a sectional view showing a configuration of another pressure measuring device according to the fourth embodiment of the present invention.

FIG. 12 is an explanatory diagram of a main part of FIG. 11;

FIG. 13 is a block circuit diagram of a pressure measuring device according to a fifth embodiment of the present invention.

FIG. 14 is a sectional view showing a configuration of a conventional pressure measuring device.

FIG. 15 is a sectional view of a main part of FIG. 14;

[Explanation of symbols]

 21, 41, 51, 61, 71 Pressure measuring device 22 Semiconductor pressure sensor 22b Pressure guiding tube 22c Lead wire 22d Package portion 22e Pressure sensor chip 23, 43, 53 First sensor fixing member (fixing means) 23a, 43a, 53a First insertion port 23b, 43b, 53a Second insertion port 53d Cylindrical part 24, 44, 54 Second sensor fixing member (fixing means) 24a, 44a, 54a Third insertion port 26, 56 Housing (storage part) 26a, 56a Bottom part 26b, 56b Projection part 26c, 56c Pressure guiding port 26f, 56e Screw part 26h, 56h Side wall part 29 Housing cap (storage part) 30 Connector 31 Circuit board 33 Signal line 42 Lead frame 62a First board 62b First board Second board 62c Third board 72 Diagnostic circuit

Claims (9)

[Claims] A semiconductor pressure sensor having a pressure guide tube and a lead wire; fixing means for fixing the semiconductor pressure sensor; a circuit board attached to the fixing means and connected to the lead wire of the semiconductor pressure sensor. A storage portion for storing the semiconductor pressure sensor, the fixing means, and the circuit board, wherein the storage portion has a protrusion outside a bottom portion thereof, and the pressure guide tube of the semiconductor pressure sensor is provided on the protrusion. A pressure measuring device, characterized in that a pressure guiding port into which a pressure-sensitive material is inserted is provided, and a screw portion is formed on the outer periphery of the projection. 2. A cup-shaped housing having a protrusion on one side of a bottom and a cylindrical side wall on the other side of the bottom, and provided in contact with the bottom in the side wall of the housing. A fixing means provided in the fixing means, a semiconductor pressure sensor in which a pressure sensor chip is housed in a package portion having a pressure guiding tube and a lead wire, and a semiconductor pressure sensor provided in the side wall of the housing. A circuit board connected to the lead wire, and a housing cap having a connector connected to a signal line from the circuit board, wherein the fixing unit is inserted with the package portion of the semiconductor pressure sensor. A first sensor fixing member having a first insertion opening and a second insertion opening into which the lead wire is inserted, and the pressure guiding tube of the semiconductor pressure sensor being inserted; And a second sensor fixing member having a third insertion port, wherein the housing has a pressure guiding port through which the pressure guiding tube of the semiconductor pressure sensor is inserted into the bottom portion and the protrusion, with the third insertion port. A pressure measuring device, which is provided coaxially and has a screw portion formed on the outer periphery of the projection. 3. A cup-shaped housing having a projection on one side of a bottom and a cylindrical side wall on the other side of the bottom, and provided in contact with the bottom in the side wall of the housing. A fixing means provided in the fixing means, a semiconductor pressure sensor in which a pressure sensor chip is housed in a package part having a pressure guiding tube and a lead wire, and a semiconductor pressure sensor provided in a side wall part of the housing, and A circuit board to which a lead wire of the semiconductor pressure sensor is connected via a lead frame; and a housing cap having a connector to be connected to a signal line from the circuit board. A first sensor fixing member having a first insertion port into which the lead frame is inserted and a second insertion port into which the lead frame is inserted; and the semiconductor pressure sensor. A second sensor fixing member for fixing the lead frame, the housing having a third insertion hole into which the pressure guiding tube is inserted; A pressure measuring device, wherein a pressure guiding port into which a pressure tube is inserted is provided coaxially with the third insertion port, and a screw portion is formed on an outer periphery of the projection. 4. A cup-shaped housing having a protrusion on one side of a bottom and a cylindrical side wall on the other side of the bottom, and provided in contact with the bottom in the side wall of the housing. A fixing means provided in the fixing means, a semiconductor pressure sensor in which a pressure sensor chip is housed in a package portion having a pressure guiding tube and a lead wire, and a semiconductor pressure sensor provided in a side wall of the housing, A circuit board to which a lead wire of the semiconductor pressure sensor is connected via a lead frame; and a housing cap having a connector to be connected to a signal line from the circuit board. Having a first insertion opening into which the lead frame is inserted and a second insertion opening into which the lead frame is inserted, and protruding along the side wall of the housing. A first sensor fixing member having: a first sensor fixing member having a third insertion hole into which the pressure guiding tube of the semiconductor pressure sensor is inserted, and a second sensor fixing member fixing the lead frame; Is characterized in that a pressure-guiding port into which the pressure-guiding tube of the semiconductor pressure sensor is inserted is provided coaxially with the third insertion port at the bottom and the projection, and a screw portion is formed on the outer periphery of the projection. And a pressure measuring device. 5. The sensor according to claim 3, wherein the lead frame is fixed to the second sensor fixing member so as to be connected to a lead wire from the semiconductor pressure sensor and the circuit board. Pressure measuring device. 6. A circuit board, comprising: a first board including a sensor drive circuit and a temperature compensation circuit; amplification of a sensor output;
A second substrate including an offset adjustment circuit and a third substrate including a current conversion of a sensor output or a digital conversion circuit;
The pressure measuring apparatus according to claim 4, further comprising: a substrate. 7. The pressure measuring device according to claim 6, wherein the circuit board is detachably provided. 8. The pressure measuring device according to claim 1, wherein the circuit board has a diagnostic circuit for performing a self-diagnosis of the semiconductor pressure sensor. 9. The pressure measuring device according to claim 2, wherein the connector is detachably provided on the housing cap.