JP2661642B2 - Pressure sensor - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a pressure sensor having a capacitive pressure transducer, and more particularly to a pressure sensor having an improved assemblability of an electric circuit and a pressure transducer and a suitable pressure transducer trimming technique. is there.

[0002]

2. Description of the Related Art FIG. 6 is a sectional view of a conventional pressure sensor, in which a capacitive pressure transducer 2 is provided in a housing 1, a hollow supporting member 5 for holding the pressure transducer 2, and
An electric circuit 4 using an electric circuit board 3 supported at a predetermined interval between the pressure transducer 2 and a cup-shaped electric circuit having a plurality of connector terminals 6 coupled to the electric circuit 4. And a connector 7.

The electric circuit 4 has an electric circuit board 3 having electronic components mounted on both sides. The circuit board 3 and a plurality of connector terminals 6 projecting into an electric connector 7 are connected to the connector 8 of the circuit board 3. It is electrically connected via a terminal protrusion 6a which can be inserted and removed.

The electric circuit 4 (electric circuit board 3)
The pressure transducer 2 and the pressure transducer 2 are electrically connected by metal terminals 9 and 10 which are disposed on a side 2a opposite to the pressure receiving surface of the pressure transducer 2 and project vertically from the opposite side.

[0005]

In the prior art pressure sensor, a connector terminal 6 provided on an electric connector 7 and the electric circuit 4 are electrically connected via a terminal protrusion 6a capable of fitting and removing. If there is a bend or dimensional variation in the projecting portion 6a integral with the connector terminal 6 that transfers signals to the outside in the mass production assembling process,
This has a disadvantage that the terminal protruding portion 6a may not be fitted to the connector 8 well.

The characteristic variation of the capacity change with respect to the pressure of the pressure transducer 2 has been adjusted by the electric circuit 4. However, since the adjustable range is narrow, the inherent variation of the pressure transducer 2 is reduced. I needed to.

SUMMARY OF THE INVENTION An object of the present invention is to obtain an inexpensive and reliable performance pressure sensor by improving the structure of the pressure sensor and the trimming method / structure for improving the yield of the pressure transducer.

[0008]

SUMMARY OF THE INVENTION The present invention comprises a housing having a pressure inlet, a capacitive pressure transducer disposed within the housing, and fixed within the housing at a predetermined distance from the pressure transducer. An electric circuit using an electric circuit board having electronic components mounted on both sides thereof, a hollow support member for supporting the electric circuit board, and a cup-shaped housing including the support member and the circuit board and being coupled to the housing. A pressure sensor comprising an electrical connector, the electrical connector having a plurality of connector terminals that penetrate a main body and are electrically coupled to the circuit board, and a flange portion that includes the circuit board and a support member. A recess in which the pressure transducer receives a plurality of terminals protruding from the circuit board, and a plurality of metal terminals provided in the recess and to which the protruding terminals are joined; A protruding terminal metal terminal and the circuit board of the pressure transducer is intended to be subject matter of the pressure sensor with electrically coupled recessed portion.

Further, the present invention may be a pressure sensor in which a fixed capacitor or a variable capacitor is electrically coupled as an electric circuit between metal terminals of the transducer in the recessed portion of the pressure transducer.

[0010]

The metal terminal of the pressure transducer is provided in the recess,
Since the terminal protruding from the electric circuit board included in the flange portion of the electric connector and the metal terminal of the pressure transducer are electrically joined at the recessed portion, a fitting mistake is avoided and assembly is easy. .

In a case where a fixed capacitor or a variable capacitor for absorbing and trimming variations in capacitance characteristics corresponding to the pressure of the converter is electrically connected to the converter in the recess, the conversion may be performed. Variations in the capacitance characteristic inherent to the device can be widely accepted, which can improve the yield and simplify the adjustment in the electric circuit.

[0012]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS One embodiment of the present invention will be described below with reference to FIGS. FIG. 1 is a plan view of a pressure sensor 11 of the present invention.
FIG. 2 shows a front view of the external appearance, and FIG.
Is shown in

In the housing 12, a flat disk-shaped diaphragm 15 of a capacitive pressure transducer 14 which receives pressure through a pressure inlet 13 is hermetically sealed with a gasket 16 or the like. On the opposite side, an electric circuit 22 contained in a flange portion 18b of the electric connector 18 and a hollow support member 17 are arranged so as to overlap the pressure transducer 14, and the housing 1
The second opening edge 12a is fixed by caulking or the like.

The pressure transducer 14 has a diaphragm 15 formed of a ceramic material such as alumina, and the diaphragm 15 is disposed to face the ceramic base 19 at a predetermined distance by a glass sealing material or the like. On the opposing surface of the diaphragm 15 and the ceramic base 19,
Capacitors having a capacitance that varies with applied pressure are formed of metallization.

The pressure transducer 14 and the electric circuit 2 according to the present invention
2 is electrically connected by soldering. In the embodiment shown in FIG. 3, the output of the pressure transducer 14 is concaved from one surface 19a of the ceramic base 19 to the side wall surface 19b (recess 19c) and is fixed via fan-shaped metal terminals 20 and 21. Drawn out. This pressure transducer 14
Is shown in FIG. 4 (a).

The protruding terminals X and Y protruding from the circuit board 23 and the metal terminals 20 and 21 of the pressure transducer 14
It is configured to couple at the position of the recess 19.
The connection between the metal terminals 20 and 21 and the protruding terminals X and Y is securely fixed by soldering from the side wall surface 19b side of the converter ceramic base 19 using a soldering device such as a light beam or a heater.

The circuit board 23 is positioned at a predetermined distance from the pressure transducer 14 by a support member 17 which is formed into a hollow cylindrical shape with an electrically insulating material such as polybutylene terephthalate. The circuit board 23 includes an electric circuit 22 that outputs an electric signal corresponding to the pressure applied to the capacitive pressure transducer 14.

The electric circuit 22 is disclosed in, for example, Japanese Patent Laid-Open No. 2-78.
Although the detailed description is omitted because it is disclosed in Japanese Patent Application Laid-Open No. 912, it is noted that it has circuit components such as an integrated circuit unit, a resistor, and a capacitor. In this embodiment,
The electric circuit 22 has an electric circuit board 23 having through holes on both sides made of a ceramic material having good heat resistance and humidity resistance.

The electrical connector 18 is formed of an electrical insulating material such as polybutylene terephthalate reinforced with glass, and is disposed in a superposed relationship with the support member 17 included therein. The electric connector 18 has a cup shape, and has a plurality of connector terminals 24, 25, and 26 for transmitting and receiving signals to the outside, and a connector for covering / connecting the connector terminals 24-26. A guide cylinder 18a, a projection 18d for preventing a connector coupled with the guide cylinder 18a from coming off, and an inner cylinder 27 engaged with the projection 18d and fitted inside the guide cylinder 18a. , One side 1 of the pressure transducer 14 including the support member 17 and the electric circuit 22.
Flange part 1 which extends by integral molding to the point where it overlaps 9a
8b. The electric components of the electric circuit 22 are mounted in the internal cavities 28 and 29 defined by the circuit board 23 of the connector 18.

The connector terminals 24, 25, and 26 extend through the body of the electrical connector 18 to one surface of the circuit board 23, and are soldered to the circuit board 23 stably fixed in the flange 18b. They are electrically connected by attachment or the like. Further, an annular groove is provided on the outer periphery of the flange portion 18b of the connector 18, and the O-ring 30 is
By inserting as described above, it is possible to prevent moisture and harmful dust from entering from the swaged portion of the housing edge 12a.

Since the pressure sensor according to the present invention is of a capacitive type, the adjustment of the electric circuit 22 to the pressure transducer 14 needs to be performed after the pressure sensor 14 is mounted on the housing 12 in order to avoid the influence of an external electric field or stray capacitance. 1 and 3
As shown in FIG. 7, the electric connector 18 is provided with a plurality of adjustment holes 31 and 32 penetrating from the inner bottom surface 18e of the guide tube portion 18a to the opposite surface 18f, and a rotary driver or the like inserted from outside through the adjustment holes 31 and 32 Is used to adjust the trimmer capacitor 33 of the electric circuit 22.

When the adjustment of the trimmer capacitor 33 is completed, a rubber stopper 34 integrally formed with a bellows-like packing is provided in the adjustment holes 31 and 32 to prevent moisture from entering from outside.
Are inserted so as to seal the openings of the respective adjustment holes 31 and 32.

It should be noted that the pressure sensor of the present invention is not limited to the above embodiment, and for example, FIG.
The pressure transducer 14 as shown in (c) and (d) may be applied.

The pressure transducer 14 shown in FIG. 4 (b) is replaced with a U-shaped recess 19c shown in FIG. 4 (a) which is cut away from one surface 19a of the ceramic base 19 to the side wall surface 19b.
The two metal terminals 20 and 21 are recessed from one surface 19a of the ceramic base 19 and are circular recesses into which the metal terminals 20 and 21 are fixed.

The pressure transducer 14 shown in FIG. 4C has a continuous notch-shaped recess 19c cut from one surface 19a of the ceramic base 19 to the side wall surface 19b.
9c, a plurality of metal terminals 20 and 21 are arranged so as to be opposed to and separated from each other.
The same notch 19c 'is provided on the opposite side to the recess 19c where the first base 1 is formed. When the notch of the ceramic base 19 becomes large, the notch 19c' becomes asymmetric in the manufacturing process of molding and firing the raw material. Therefore, it is effective to improve dimensional stability.

The pressure transducer 14 shown in FIG. 4D has a circular recess 19c provided in a side wall surface 19b of a ceramic base 19, and metal terminals 20 and 21 are arranged in the recess. 19a and the metal terminal 20,
21 are in electrical communication within the ceramic base.

FIG. 5 shows a technique for trimming the characteristics of the pressure transducer 14. For example, as shown in FIG. 5A, a plurality of metal terminals 20 and 21 are arranged at predetermined intervals in a continuous notch-shaped recess 19c provided from one surface 19a of the ceramic base 19 to a side wall surface 19b. A surface-mounted fixed capacitor 3 is provided between the metal terminals 20 and 21.
5 are electrically connected through a conductive pattern and fixed by soldering. Similarly, in FIG.
A surface-mount type variable capacitor 36 is connected between the metal terminals 20 and 21 provided in c in the same manner as in (a).

In the present invention, the metal terminal 2 of the pressure transducer 14
The above-mentioned components (surface-mounted fixed capacitor 35 or variable capacitor 36) are installed between 0 and 21 so as to be electrically connected in parallel or in series or in series-parallel from the viewpoint of connection of an electric circuit. It is composed of

Further, although not shown, the variable capacitor 36 may be a conductive pattern directly printed on the ceramic base 19 in a comb shape or the like. This is because the variable print capacitor can be configured to be adjusted by a laser or the like in a known manner.

[0030]

According to the pressure sensor of the present invention, since it is possible to electrically connect to the electric circuit at the position of the recess provided in the pressure transducer, the assembly can be easily and reliably fixedly connected. Can be obtained. Further, since a trimming capacitor can be added to the recess of the pressure transducer, it is possible to absorb a variation in the pressure-capacity characteristic of the pressure transducer and to obtain an effect of increasing the product yield. Furthermore, since the pressure transducer has a disk shape and has no convex portions on the surface, there is an advantage that handling in manufacturing is easy.

[Brief description of the drawings]

FIG. 1 is a plan view of a pressure sensor according to an embodiment of the present invention.

FIG. 2 is an external front view of the pressure sensor.

FIG. 3 is a longitudinal sectional view taken along line AA ′ of FIG. 1;

FIG. 4 is an external perspective view showing a configuration of a pressure transducer built in the pressure sensor.

FIG. 5 is an external perspective view of a main part showing another embodiment of the pressure transducer.

FIG. 6 is a longitudinal sectional view showing a conventional pressure sensor.

[Explanation of symbols]

12 housing, 13 pressure inlet, 14 capacitive pressure transducer, 15 diaphragm, 18 electrical connector,
19c: recess, 20, 21: metal terminal, 22: electric circuit, 23: electric circuit board, 24, 25, 26: connector terminal, 35: fixed capacitor, 36: variable capacitor.

Claims (2)

(57) [Claims] 1. A housing having a pressure inlet, a capacitive pressure transducer disposed in the housing, and electronic components mounted on both surfaces fixed in the housing at a predetermined distance from the pressure transducer. A pressure circuit comprising: an electric circuit using the mounted electric circuit board; a hollow support member that supports the electric circuit board; and a cup-shaped electric connector that includes the support member and the circuit board and is coupled to the housing. In the sensor, the electrical connector has a plurality of connector terminals that penetrate a main body and are electrically coupled to the circuit board, and a flange portion that includes the circuit board and a support member, and the pressure transducer is A recess for receiving a plurality of terminals protruding from the circuit board; and a plurality of metal terminals provided in the recess and to which the protruding terminals are joined. And a protruding terminal of the circuit board is electrically connected at a recessed portion. 2. The recess is a continuous notch-shaped recess cut from one surface of a pressure transducer to a side wall surface, and a plurality of metal terminals are arranged at predetermined intervals in the recess.
The pressure sensor according to claim 1, wherein a fixed capacitor or a variable capacitor of a surface mount type is electrically connected between the metal terminals.