JPS6256830A - pressure transducer - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

[Detailed Description of the Invention] [Field of Application of the Invention] The present invention relates to a pressure transducer using a semiconductor strain gauge,
In particular, the present invention relates to a pressure transducer equipped with a back pressure introduction structure suitable for detecting the working oil pressure of automobiles, construction machinery, etc.

[Background of the invention]

As a pressure transducer of this kind, Utility Model No. 60-33640
The technique described in the publication is publicly known. This device is.

A back pressure introduction pipe is provided on the upper surface of the central recess of the superimposed structure of the semiconductor substrate and the IC amplifier. This known technology is
Although this method is advantageous as a direct pressure introduction method, it has the disadvantage that it is difficult to extract electrical signals through a single insulating cover from a stacked structure of a semiconductor substrate and an IC amplifier mounted on a single insulating cover.

As a known technique different from the above, there is a pressure transducer described in Japanese Utility Model Publication No. 58-5232. Since this known technique does not include an amplifier within the pressure transducer, it is necessary to use a separate amplifier.

[Purpose of the invention]

The present invention has been made in view of the above-mentioned circumstances, and it is easy to extract voltage signals, has a built-in amplifier, and has no risk of pressure fluid gushing out even if the semiconductor strain gauge is damaged. It is an object of the present invention to provide a pressure transducer that is a highly accurate relative positive pressure sensor.

[Summary of the invention]

In order to achieve the above object, the pressure transducer of the present invention has a semiconductor strain gauge that converts pressure into an electrical signal and a metal diaphragm, which are spaced apart from each other, and silicone oil is sealed in the space formed between them.

A pressure sensitive part formed by the semiconductor strain gauge is housed in a housing, covered with a base with an outer edge, an integrated circuit is housed in the base with an outer edge, and a back pressure is applied to the back side of the pressure sensitive part. It is characterized by being configured so that the introduction is communicated.

[Embodiments of the invention]

Embodiments of the present invention will be described below through FIGS. 1 to 7. ]- is a housing integrally connected with a mounting threaded pipe 1b, and the inner surface of the threaded pipe 1b forms a pressure introduction hole 1c.

The pressure sensitive body 2 is housed in the inner cavity 1d provided in the center of the housing [2, 2, and is fixed by applying plastic flow processing to the upper surface 1e of the housing.

The above pressure sensitive body 2 has a semiconductor strain gauge mounted on a glass stand 2b.
After the Jk electrodes are joined, they are fixed to the central concave portion of the pressure sensitive body 2 using an organic adhesive or the like. There is a back pressure introduction hole 2b-]- in the center of the glass stand 2b, which communicates with the back pressure introduction hole 2C at the center of the pressure sensitive body. Further, 2d is a lead bin which is vertically sealed to the pressure sensitive body 2. One end of the lead bin 2d is connected to the semiconductor strain gauge 2a via a gold wire 2e, and the other end is connected to the integrated circuit board 5 through a terminal 4a. and are connected via aluminum m5a. A silicone oil 2f is sealed in the pressurizing surface of the semiconductor strain gauge 2a by a metal diaphragm 2g, and the metal diaphragm 2g is sealed by a pressurizing plate 2.
It is fixed by plastic flow processing at the pressure sensitive body opening 2m via h.

3 shown in FIG. 1 is a mold base with an outer edge. Figure 2 is a perspective view of the single item (top side), and a perspective view of the single item (top side) is shown in Figure 2.
The back side) is shown in FIG. 3. This molded base 3 with an outer edge is provided with a guide groove 3a for the legibin 2d, a mounting hole 3d, and a back pressure introducing slit 3c. A board base 4 on which an integrated circuit board 5 is mounted in advance is housed in this molded base 3 with an outer edge. FIG. 4 shows a perspective view of its outline. The board base 4 has a plurality of terminals 4a and 4b, and these terminals are connected to the aluminum pins 5a and aluminum wires 5b of the board 5, respectively.
wire bonded by

Reference numeral 4c denotes a mounting hole, and the mold base 3 with outer edge and the substrate base 4 are integrally fixed to the housing by means of the mounting screws 6 shown in FIG. Furthermore, 4d is a screw hole integrally molded with the substrate base 5, into which the mounting screw 7 shown in FIG. 1 is screwed. Reference numeral 8 shown in FIG. 1 is a shield base, at one end of which a feedthrough capacitor 9 is arranged, and a terminal base 10 is mounted on the shield base. Terminal base】7
0 is molded with a terminal connector 10a buried therein, and one electrode of a feedthrough capacitor 9 is connected to the terminal connector lQa by spot welding.

The other pole of the feedthrough capacitor 9 is connected to the terminal 4b of the substrate base 4. The shield base 8 and the terminal base 10 are fixed to the substrate base by the aforementioned mounting screws 7.

An integrated circuit board 5 is placed inside the mold base 3 with an outer edge.
Then, the U-shaped terminal Oa is passed through the cover rubber plugs 1 and 2 and penetrated through the cover] and 3 and welded to one end of the pin terminal 15a of the molded connector 15.

In the above configuration, even if the pressure sensitive body 2 were to break, there is no risk of pressure fluid spouting out because the metal diaphragm 2g is provided.

The cover 13 shown in FIG. 1 is snap-tightened all around the flange-like maximum diameter portion of the housing 2 via an O-ring 16. Reference numeral 17 denotes an O-ring, which is fitted into a groove provided on the bottom surface of the molded connector 15. 18 is a protect tube after the U-shaped connector 10a and the pin terminal 15a are welded.

It is inserted into a molded connector 15 and fixed with a filler 19. FIG. 5 shows an external perspective view of the molded connector 15. The molded connector 15 has two mounting holes 15b, and the screw 20 shown in FIG. 1 is inserted through the second hole.
' is fixed to the cover 13. Mounting hole 1 after fixing
5b is filled with a filler.

Figure @6 is a front view of the molded connector.

In FIGS. 1 and 6, 15C indicates a back pressure communication hole, which is disposed between the two waterproof walls 15d shown in FIGS. 5 and 6.

FIG. 7 is a sectional view of the molded connector 15.

FIG. 3 is an explanatory diagram showing correspondence between insertion connectors 20 (indicated by imaginary lines). The back pressure communication hole 15c has the effect of indirectly protecting the insertion connector from water entering from one direction by the bottom portion 20a of the insertion connector 20 as shown in FIG.

FIG. 8 is a sectional view showing an application example of the present invention.

In this application example, atmospheric pressure is introduced as back pressure through a back pressure introducing pipe 21a that is integrally arranged with the lead wire 21, and the lead wire 21 is communicated with the back pressure.

As a further different application example, there is a method in which the core wire 21b of the lead 1121 is lightly twisted to maintain air permeability without using the introduction pipe 21a.

The pressure transducer according to the present invention configured as described above is attached to a predetermined position in the fluid conduit by the mounting screw 1b of the housing. The metal diaphragm 2g is pressurized by the fluid, and the semiconductor strain gauge 2a is pressurized via the silicone oil 2f. A Wheatstone bridge is formed on the gauge pattern surface, and the pressure is taken out as an electrical signal, guided to the integrated circuit board 5 through the gold wire 2e, lead pin 2d, and terminal 4a, and amplified. The amplified electrical signal is transmitted to the terminal 4b, the feedthrough capacitor 9, the U-shaped connector (terminal) 10a, and the pin terminal 15a.

On the other hand, the back pressure of the conductor strain gauge 2a is introduced into the cover 13 through the back pressure communication hole 15c of the mold connector, passes through the back pressure introduction slit 3C on the bottom of the molded base 3 with an outer edge, and is further introduced into the pressure sensitive body. It is introduced through the back pressure introduction hole 2C of No. 2 and the back pressure introduction hole 2b-1 of the glass stand 2b.

As described above, the device of this embodiment can reliably separate the soft gel 22 on the integrated circuit board 5 from the back pressure introduction passage, making it possible to construct a highly accurate relative positive pressure sensor.

In addition, in the conventional technology, when the back pressure introduction pipe is placed upright and a hole is made in the integrated circuit to protrude to the top of the soft gel, the pipe becomes an obstacle and the function i! 1Ilv! In this embodiment, the degree of freedom in pattern design was restricted due to the problem that it was difficult to do threaded pipe 1.
Since the structure has a screw-in structure in which the pressure sensitive part 2 and the integrated circuit board 5 are overlapped, the problem with the prior art described above (the pipe gets in the way and the degree of freedom in design is restricted) is avoided. ) has been resolved.

〔Effect of the invention〕

As described in detail above, when the present invention is used continuously, it is easy to extract electrical signals, it has a built-in amplifier, and even if the semiconductor strain gauge in the pressure sensing part is damaged, there is no risk of pressure fluid spewing out, and high The pressure transducer can be configured to be an accurate relative positive pressure sensor.

[Brief explanation of drawings]

Fig. 1 is a front sectional view of one embodiment of the present invention, Fig. 2 is a perspective view of the top side of the mold base with an outer edge in the above embodiment, Fig. 3 is a perspective view of the bottom side of the mold base, and Fig. 4 is the same. FIG. 5 is a perspective view of the external appearance of the board base and the board, FIG. 5 is a perspective view of the external appearance of the molded connector, FIG. 6 is a front view of a portion of the molded connector, and FIG. 7 is a correspondence between the molded connector and the insertion connector. It is an explanatory diagram drawn. FIG. 8 is a front sectional view of an embodiment different from the above. DESCRIPTION OF SYMBOLS 1...Housing, 1a...Threaded pipe, 1G...Pressure introduction hole, 1d...Inner cavity, 2...Pressure sensitive body, 2a...
・Semiconductor strain gauge, 2b...Glass stand, 2b-1, 2
c...back pressure introduction hole, 2d...lead pin, 2θ...
・Gold wire, 2f... Silicone oil, 2g... Metal diaphragm, 3... Mold base with outer edge, 3a.
... Guide groove, 3b... Mounting hole, 3C... Back pressure introduction slit, 4... Board base, 4a, 4b... Terminal, 4C... Mounting hole, 4d... Screw hole, 5...
・Integrated circuit board, 5a...aluminum pad, 5b...
Aluminum wire, 6, 7... Mounting screw, 9... Feedthrough capacitor, 10... Terminal base, 10a... U-shaped connector, 12... Cover rubber plug, 13... Cover, 15... ...Mold connector, 15a...Bin terminal, 15c...Back pressure communication hole, 15d...Waterproof wall,
L6, 17... O-ring, 18... Protect tube, 19... Filler, 20... Insertion connector. 21... Lead i1.21a... Back pressure introduction pipe,
21b... Core wire, 22... Soft gel.

Claims (1)

[Claims] 1. A semiconductor strain gauge that converts pressure into an electrical signal and a metal diaphragm are spaced apart from each other, silicone oil is filled in the space formed between them, and the semiconductor strain gauge is formed by the above semiconductor strain gauge. The pressure sensitive part to be used is housed in the housing,
A pressure transducer, characterized in that it is covered with a base with an outer edge, an integrated circuit is housed in the base with an outer edge, and a back pressure is introduced and communicated with the back side of the pressure sensitive section. 2. The pressure transducer according to claim 1, wherein the housing is an integrally connected threaded pipe having a central hole that communicates with pressure fluid. 3. The configuration for introducing and communicating the back pressure is a back pressure that is provided to communicate between a plurality of waterproof protective walls provided on the mounting surface of the connector attached to the cover that covers the base with an outer edge. The pressure transducer according to claim 1, characterized in that the pressure transducer includes an introduction hole.