JP2002228535A - Pressure sensor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an easily-manufacturable pressure sensor capable of shortening the longitudinal size. SOLUTION: This sensor is equipped with a joint 3 on which a sensor module 2 is mounted, a flange 4 for fixing the joint 3 on an installation part, a circuit board 5 mounted on the flange 4, an a casing 6 for storing the circuit board 5 except a part thereof. A circuit part 11 and a terminal part 12 of the circuit board 5 have a lead frame 11A of a metal plate, and a resin mold is provided on the lead frame 11A. The joint 3 and the flange 4 are formed separately. Therefore, when the joint 3 is welded on the sensor module 2, the flange 4 is not a hindrance in the work.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a pressure sensor for converting the pressure of a fluid into an electric signal and outputting the electric signal to the outside.

[0002]

2. Description of the Related Art A pressure sensor that detects a pressure to be detected and converts it into an electric signal is used for measuring a fluid pressure. Such a pressure sensor, a joint that is fastened and fixed to the installation portion, a sensor module attached to the joint, a circuit portion that is electrically connected to the detection element of the sensor module,
A terminal unit for inputting and outputting an electric signal from the circuit unit, and a fluid pressure guided into the pressure introducing hole of the sensor module is detected by a detection element of the sensor module.

FIGS. 6 to 8 show a conventional example of such a pressure sensor. 6 and 7 show a first conventional example of a pressure sensor. In these figures, Conventional Example 1
Here, a sensor module 101 is attached to a joint 102 by beam welding or the like, and a substantially cylindrical housing 103 having a node therein is attached to the joint 102. Inside the housing 103, a spacer 104 is attached to the joint 102, and a circuit board 106 is attached to the spacer 104. Further, a terminal portion 108 is attached to the spacer 104 via a terminal block 107.

FIG. 8 shows a second conventional example of a pressure sensor. This conventional example 2 is disclosed in Japanese Patent Application Laid-Open No. 11-237291. 8, in the conventional example 2, the sensor module 201 is fixed by welding to the tapered joint 202A of the joint 202, and the substantially cylindrical housing 20 is fixed to the flange 202B of the joint 202 via the caulking mechanism 202C.
3 is attached. Inside the housing 203, a circuit board 205 is attached to the joint 202 via a case 204. Further, the circuit board 20
5 is provided with a terminal portion 207 via a terminal block 206. The circuit board 205 and the pressure detecting element of the sensor module 201 are electrically connected by a pedestal 208.

[0005] In Conventional Examples 1 and 2, the joint 102,
202 is fixed to the installation portion by screwing, so that it also serves as a flange as an attachment portion. Further, the sensor modules 101 and 201 are fixed to the joints 102 and 202 by welding. Housing 103, 20
3 is a caulking mechanism 102A, 20 attached to the joint 102, 202.
Attached via 2C.

[0006]

SUMMARY OF THE INVENTION Conventional Example 1 and Conventional Example 2
The pressure sensor has a structure in which the joints 102 and 202 also function as a flange, in other words, the joints 102 and 202 and the flange are integrally formed. In the pressure sensor of Conventional Example 1, since the sensor module 101 is welded and fixed to the joint 102, the joint of the joint 102 is formed so as to protrude, so that the length dimension of the pressure sensor itself becomes long. There is a point. On the other hand, in the pressure sensor of Conventional Example 2, the sensor module 201
02 is fixed by welding so as to be embedded in the tapered joint portion 202A of FIG. 02, so that the problem that the length dimension of the pressure sensor itself becomes long can be avoided. Thus, there is a problem that welding work such as alignment of welding lines is complicated.

In the pressure sensors of the first and second conventional examples, the circuit boards 106 and 205 and the terminals 108 and 207 are arranged on the sensor modules 101 and 201 in order not to increase the outer diameter. Therefore, the spacer 104, the terminal block 107, the case 204, the pedestal 208, and the terminal block 206 are required, and the number of parts is increased, and the total length of the sensor is disadvantageously increased.

An object of the present invention is to provide a pressure sensor whose length can be reduced and which can be easily manufactured.

[0009]

SUMMARY OF THE INVENTION Therefore, the present invention aims at achieving the above object by forming a joint and a flange, which are conventionally formed integrally, separately from each other. Specifically, the pressure sensor of the present invention includes a sensor module that receives a pressure and converts the signal into an electric signal, a joint having the sensor module attached and a pressure introducing hole formed therein, and And a circuit board mounted on the flange and amplifying the electric signal from the sensor module, and a housing attached to the flange while accommodating the circuit board except for a part thereof, The circuit board has a circuit portion for amplifying and processing an electric signal, and a terminal portion for inputting and outputting the electric signal from the circuit portion, and a lead frame in which the circuit portion and the terminal portion are formed from a metal plate. The metal plate is provided with a resin mold for electrically insulating the lead frame, and the flange has an inner peripheral surface formed by the sensor module. To be arranged so as to face, characterized in that it is formed separately from the said joint and the flange.

In the present invention, the sensor module is welded and fixed in a state where the joint is abutted on the sensor module, and the flange is welded and fixed to the joint. Further, a circuit board is provided on the flange to assemble the pressure sensor. When welding the joint to the sensor module, there is no obstruction in the welding operation because no flange is provided. Therefore, welding does not need to be performed from an unnatural direction such as an oblique direction or a vertical direction, so that operations such as welding line alignment can be easily performed, and as a result, the pressure sensor can be easily manufactured.

When the flange is attached to the joint to which the sensor module is welded, the length of the pressure sensor itself is reduced because the sensor module is immersed inside the flange. Since the circuit board is attached to the flange, members such as a support stand and a terminal block are not required for installing the circuit board. Therefore, the number of parts is reduced, and the number of parts assembling steps is reduced, which also facilitates the manufacture of the pressure sensor.

Further, since the lead frame of the circuit portion and the terminal portion is formed from the metal plate, the circuit portion and the terminal portion are electrically connected in advance, and the space between the circuit portion and the terminal portion is established. The connection work by soldering or the like is not required, and the assembly work of the sensor is simplified. Further, since it is not necessary to separately provide a relay terminal for connecting the terminal section to the circuit section, the number of parts is reduced, and the assembly work of the sensor is simplified also from this point. Therefore, also from this point, the manufacture of the pressure sensor becomes easy. Further, since the housing is provided in the pressure sensor, a dustproof effect can be obtained. By attaching the housing to the flange by welding or the like, the manufacturing of the pressure sensor can be facilitated from this point as well.

Here, in the present invention, it is preferable that the housing is electrically conductive. In this configuration, the conductive casing shields electromagnetic waves from the outside, so that adverse effects on the circuit board due to the electromagnetic waves from the outside, for example, noise can be eliminated.

[0014]

DESCRIPTION OF THE PREFERRED EMBODIMENTS One embodiment of the present invention will be described below with reference to the drawings. FIG. 1 is a cross-sectional view showing the entire pressure sensor 1 according to the present embodiment. The pressure sensor 1 is used for detecting hydraulic pressure in vehicles, and can be applied to ships, heavy equipment for construction, refrigeration machines, and other various devices, and can be applied to pressure detection of arbitrary fluids such as air pressure and water pressure. it can. In FIG. 1, a pressure sensor 1 includes a sensor module 2 and a joint 3 to which the sensor module 2 is attached.
A flange 4 for fixing the joint 3 to a portion to be installed (not shown); a circuit board 5 and a housing 6 provided on the flange 4 respectively; and a gasket provided between the circuit board 5 and the housing 6 7 are provided.

The sensor module 2 includes a diaphragm 2A
Is a substantially cylindrical metal member provided on the end face and the ring portion 2B provided at the center of the peripheral surface. This metal member is a metal excellent in mechanical strength, corrosion resistance and spring property (elasticity), for example, precipitation hardening stainless steel SUS630.
Formed from The surface of the diaphragm 2A is formed in a circular shape, and a pressure detecting element 2C constituting a bridge circuit is formed on the surface. This pressure detecting element 2C
Is composed of a strain gauge via an insulating film such as silicon oxide, and converts into an electric signal when receiving a pressure. As shown in FIG. 2A, the inner peripheral portion 2D of the sensor module 2 is formed as an introduction hole for introducing a detected pressure to the back surface of the diaphragm 2A. A smooth joint surface 2 </ b> E that joins the joint 3 is formed on the end face on the opening side of the sensor module 2.

As shown in FIG. 2B, the joint 3 is a substantially cylindrical member made of metal. The material used for this metal member varies depending on the pressure range of the fluid. That is, in the low / medium pressure range (for example, 100 MPa or less), ferritic or austenitic stainless steel (for example, SUS430, S
US304 etc., and in a high pressure range (for example, exceeding 100 MPa), precipitation hardening stainless steel (for example, SU
S630) is used.

The joint 3 has a shape in which a flange 3A for connecting a flow path (not shown) through which a pressure to be detected flows is formed so as to protrude from the main body 3B. The main body 3B is a sealing surface for sealing between the main body 3B and the installation portion. At the end opposite to the main body 3B across the flange 3A of the joint 3,
A joining cylinder portion 3D for joining with the sensor module 2 is integrally formed, and the joining cylinder portion 3D has a joining surface 3E having the same size as the joining surface 2E of the sensor module 2 formed on an end face. The joint 3 has a pressure introduction hole 3F formed therein.

In FIG. 1, the flange 4 is a substantially cylindrical member made of metal. As shown in FIG. 2 (C), the outer peripheral surface of the flange 4 is a fixing surface 4B for fixing the joint 3 to the installation portion, and one end surface of the flange 4 is a circuit board 5 and a housing 6.
And the other end surface is a joint surface 4D to be joined to the joint surface 3C of the joint 3. The material used for the flange 4 is preferably stainless steel, but may be general steel if there is no problem in weldability, strength and corrosion resistance.

In FIG. 3D, the circuit board 5 has a circuit portion 11 whose one surface faces the diaphragm 2A (see FIG. 1).
And a terminal section 12 for inputting and outputting an electric signal from the circuit section 11, and a connection lead frame 13 for connecting the circuit section 11 and the terminal section 12. The circuit section 11 includes a circuit section lead frame 11A and a circuit section resin mold 14 provided on the circuit section lead frame 11A. The terminal portion 12 includes a terminal portion lead frame 12D and a terminal portion resin mold 15 provided on the terminal portion lead frame 12D. The circuit part lead frame 11A, the terminal part lead frame 12D, and the connection part lead frame 13 are formed continuously,
The circuit section 11 and the terminal section 12 are arranged opposite to each other by being bent around the connection section lead frame 13.

The circuit part lead frame 11A has a terminal 11B for making an electrical connection with the pressure detecting element 2C. An IC chip 16 (see FIG. 5) is mounted on the circuit part lead frame 11A. The terminal 11B and the pressure detecting element 2C are connected to a connection portion 17 by wire bonding.
(See FIG. 1). The circuit portion resin mold 14 is provided to hold the circuit portion lead frame 11A and provide electrical insulation. The circuit portion resin mold 14 includes a positioning protrusion 14A and an engagement ring 14B that engages with the inner peripheral surface of the flange 4. And

The terminal lead frame 12D includes an input terminal 12A, an output terminal 12B, a common terminal 12C (see FIG. 4), and a mounting pad 1 on which electronic components (not shown) are mounted.
2E. The terminal portion resin mold 15 is provided for holding the terminal portion lead frame 12 </ b> D and providing electrical insulation. The positioning portion 1 has a tip abutting against a plane of the circuit portion resin mold 14.
5A.

As shown in FIG. 4, the circuit portion lead frame 11A, the terminal portion lead frame 12D, and the connection portion lead frame 13 are formed of a flexible metal plate 10, and predetermined portions of the metal plate 10 are bent. In this state, the resin mold 14 for the circuit portion and the resin mold 15 for the terminal portion are provided.

In FIG. 1, a housing 6 accommodates the circuit board 5 except for a part of the terminal portion 12, and is formed of a conductive material such as stainless steel or general steel. Housing 6
Has a cap-shaped shell portion 6A that covers the circuit board 5 and a flange portion 6B that is integrally formed on the periphery of the shell portion 6A. As shown in FIG. 3 (E), a through hole 6C through which the terminal portion 12 penetrates is formed at the center of the shell portion 6A. The flange 6 </ b> B is formed so that a portion to be joined to the flange 4 is formed smoothly, and its outer diameter is substantially equal to the outer diameter of the flange 4. In FIG. 1, a gasket 7 is
And the terminal portion resin mold 15,
It is formed in a substantially block shape.

Next, a method for manufacturing the pressure sensor 1 according to this embodiment will be described. First, a method for manufacturing the circuit board 5 will be described with reference to FIG. First, a pattern forming step is performed. In this step, the circuit board lead frame 11A, the terminal section lead frame 12D, and the connection section lead frame 13 having a predetermined pattern are formed by etching or pressing the metal plate 10 (see FIG. 4).

Thereafter, a molding step is performed as shown in FIG. In this step, the resin mold 14 for the circuit portion and the resin mold 15 for the terminal portion for holding each lead frame are attached to the metal plate 10. At this time, the resin molds 14 and 15 are provided on both surfaces of the metal plate 10, and as the material thereof, a thermosetting resin epoxy, a thermoplastic resin PBT, PPS, or the like can be used.

Further, as shown in FIG. 5B, the IC chip 16 is die-bonded to the circuit part lead frame 11A, and as shown in FIG.
And the circuit part lead frame 11A are wire-bonded to provide a connection part 17. Thereafter, as shown in FIG. 5D, the IC chip 1 is used to protect the IC chip 16.
6 is coated with silicon gel, and thereafter, as shown in FIG. 5E, a cutting step of cutting and removing unnecessary portions of the metal plate 10 is performed. Thereby, the circuit board 5 is manufactured.

The pressure sensor 1 is assembled using the circuit board 5 manufactured as described above. First, the pressure detecting element 2C is provided on the diaphragm 2A to form the sensor module 2 (sensor module forming step), and then the sensor module 2 is fixed to the joint 3 by electron beam welding. Further, the flange 4 is projection-welded to the joint 3. Thereafter, the circuit board 5 manufactured in the circuit board manufacturing process is bonded and fixed to the end surface of the flange 4 with an adhesive such as epoxy (board mounting process).

Further, the pressure detecting element 2C provided on the sensor module 2 and the terminal 11B of the circuit lead frame 11A are connected by wire bonding to form a connection 17
Is formed (connection step). After that, the terminal part lead frame 12D is bent so as to be perpendicular to the circuit part 11 with the connection part lead frame 13 as a bending center (bending step), and the gasket 7 is attached to the terminal part 12.

Thereafter, the circuit section 11 and the like are covered with the conductive casing 6 so that a part of the terminal section 12 is exposed to the outside.
The conductive housing 6 is fixed to the end face of the flange 4 by welding. At this time, the projection welding is performed over the entire circumference of the flange 6B. By these operations, the pressure sensor 1 is assembled, and the pressure sensor 1 is attached to a tank, a pipe, and the like (not shown).

According to the present embodiment, the following effects can be obtained. 1) A sensor module 2 that converts pressure to an electric signal, a joint 3 to which the sensor module 2 is attached and in which a pressure introducing hole 3F is formed, and a flange 4 for fixing the joint 3 to a portion to be installed. And a circuit board 5 attached to the flange 4 for amplifying and processing an electric signal from the sensor module 2, so that the pressure sensor 1 can appropriately detect the pressure and can be installed at a predetermined installation portion. An installable pressure sensor 1 can be provided. 2) Since the joint 3 and the flange 4 are formed separately, when the joint 3 is welded to the sensor module 2, the flange 4 does not interfere with the work. Therefore, welding does not need to be performed from an unnatural direction such as an oblique direction or a vertical direction, so that operations such as welding line alignment can be easily performed, and the pressure sensor 1 can be easily manufactured.

3) Since the inner surface of the flange 4 is opposed to the sensor module 2, the sensor module 2 is mounted on the joint 3 to which the sensor module 2 is welded. Since it is immersed inside the flange 4, the length of the pressure sensor itself is reduced. 4) Since the circuit board 5 is directly mounted on the flange 4, no special mounting member such as a support stand or a terminal block is required for installing the circuit board 5. Therefore, the number of parts is reduced, and the number of parts assembling steps is reduced. This also facilitates the manufacture of the pressure sensor.

5) The circuit board 5 includes a circuit section 11 for amplifying and processing an electric signal, a terminal section 12 for inputting and outputting an electric signal from the circuit section 11, and a connecting section lead frame 13 for connecting these. , Lead frame 11 of circuit section 11
A, the lead frame 12D of the terminal portion 12 and the connection portion lead frame 13 are formed from a metal plate 10, and the metal plate 10 is provided with resin molds 14 and 15 for holding the lead frame and providing electrical insulation. Therefore, the work of connecting the circuit section 11 and the terminal section 12 by soldering or the like becomes unnecessary, and the assembly work of the pressure sensor 1 is simplified. In addition, since it is not necessary to separately provide a relay terminal for connecting the terminal section 12 to the circuit section 11, the number of components is reduced, and this also simplifies the assembly work of the pressure sensor 1.

6) The pressure sensor 1 is provided with a housing 6 for accommodating the circuit board 5 except for a part thereof. Since the housing 6 has a structure attached to the end surface of the flange 4, the size of the circuit board 5 is large. By covering the portion with the housing 6, an excellent dustproof effect can be obtained. 7) By fixing the housing 6 to the flange 4 by welding, the manufacturing of the pressure sensor 1 can be facilitated from this point as well. 8) A part of the circuit board 5 exposed from the housing 6 is
Therefore, connection with an external power supply can be easily performed.

9) Since the housing 6 is conductive, electromagnetic waves from outside are shielded, so that adverse effects on the circuit board due to external electromagnetic waves, for example, noise can be eliminated. 10) Since the terminal portion resin mold 15 is provided through the housing 6, the terminal portion 12 is insulated from the conductive housing 6 by the terminal portion resin mold 15. No short circuit occurs and no electricity flows to the circuit section 11. Moreover, since it is not necessary to separately provide a member for insulation between the terminal portion 12 and the housing 6, the number of components can be reduced.

11) Housing 6 and resin mold 15 for terminals
Since the gasket 7 is interposed between them, the space between them is sealed with the gasket 7 to prevent dust or the like from entering the housing 6. 12) The resin mold 14 for the circuit part and the resin mold 15 for the terminal part are arranged to face each other, and the resin mold 15 for the terminal part is formed by the resin mold 14 for the circuit part and the resin mold 15 for the terminal part.
And the positioning portion 15A for positioning between the circuit portion resin mold 14 and the terminal portion resin mold 15 at a predetermined position. To be
The assembly work of the pressure sensor 1 can be further simplified.

It should be noted that the present invention is not limited to the above-described embodiment, but includes other configurations that can achieve the object of the present invention, and the following modifications are also included in the present invention.
For example, in the above embodiment, the resin mold is
The resin mold is provided on both the circuit section 11 and the terminal section 12. Further, in the present invention, it is not always necessary to provide the housing 6 and the gasket 7. Even if the housing 6 is provided, it does not need to be conductive.

[0037]

As described above, according to the present invention,
A sensor module that receives pressure and converts it into an electric signal;
A joint to which the sensor module is attached and a pressure introduction hole formed therein, a flange for fixing the joint to a portion to be installed, and a circuit board attached to the flange for amplifying an electric signal from the sensor module; The flange is disposed such that the inner peripheral surface thereof faces the sensor module, and the joint and the flange are formed separately.When welding the joint to the sensor module, the flange is Since the pressure sensor is not provided, there is no obstacle in the welding operation, and the pressure sensor can be easily manufactured. When the flange is attached to the joint, the sensor module is immersed inside the flange, so that the length of the pressure sensor itself is reduced.

[Brief description of the drawings]

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

FIG. 2A is a cross-sectional view showing a sensor module;
(B) is a sectional view showing a joint, and (C) is a sectional view showing a flange.

FIG. 3D is a sectional view showing a circuit board, and FIG. 3E is a sectional view showing a housing.

FIG. 4 is a plan view showing a state in which a resin mold is provided on a metal plate.

5A to 5E are diagrams illustrating a method for manufacturing a circuit board.

FIG. 6 is a sectional view showing a conventional example.

7 is a sectional view taken along the line VII-VII in FIG.

FIG. 8 is a sectional view showing a different conventional example.

[Description of Signs] 1 Pressure sensor 2 Sensor module 2C Pressure detection element 3 Joint 3F Pressure introduction hole 5 Circuit board 6 Housing 7 Gasket 11 Circuit section 12 Terminal section 14 Resin mold for circuit section 15 Resin mold for terminal section

Continued on the front page (72) Inventor Atsushi Imai 1-30-4 Higashimagome, Ota-ku, Tokyo Nagano Keiki Co., Ltd. F term (reference) 2F055 AA25 BB20 CC02 DD01 EE11 FF43 GG12 GG25 4M112 AA01 BA01 CA08 CA12 CA13 CA15 EA06 FA20 GA01

Claims (2)

[Claims] 1. A sensor module for receiving pressure and converting it into an electric signal, a joint having the sensor module mounted therein and having a pressure introducing hole formed therein, a flange for fixing the joint to a portion to be installed, A circuit board attached to the flange for amplifying and processing an electric signal from the sensor module; and a housing attached to the flange while accommodating the circuit board except for a part thereof, the circuit board comprising: And a terminal unit for inputting and outputting an electric signal from the circuit unit,
The circuit portion and the terminal portion have a lead frame formed of a metal plate, and the metal plate is provided with a resin mold for electrically insulating the lead frame. A pressure sensor, wherein a surface is arranged so as to face the sensor module, and the joint and the flange are formed separately. 2. The pressure sensor according to claim 1, wherein the housing is conductive.