JPH11142268A - Pressure detecting device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To secure prescribed torque around a connector without any increase in size even when a part which is caulked with a relatively small load is present. SOLUTION: This device is equipped with a sensing body 2 which has a thin part 2b, a metallic housing 1, a sensor chip 4 which is fixed to the thin part 2b, a circuit board 7 which processes the electric signal from the sensor chip 4, a terminal assembly 10 having a connector terminal 10a connected electrically to a post 7c of this circuit board 7, and a connector case 11 which is caulked and fixed to the housing 1 through an O ring 12 together with the terminal assembly 10, the part 11a on which the caulking load of the connector case 11 is applied is positioned above a corner part of a step part 1e of the housing 1, and the connector case 11 and housing 1 have a concave part and a projection part and are fixed by caulking.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a pressure detecting device for detecting pressure, which is suitable for detecting a high pressure such as a fuel pressure of a fuel injection device in a vehicle or a brake oil pressure of a brake device. is there.

[0002]

2. Description of the Related Art Conventionally, as a pressure detecting device of this kind,
Japanese Unexamined Patent Publication No. 62-73131 discloses one.
In this sensor, a sensing body having a thin-walled end portion of a pressure introducing hole is housed in a housing, a displacement of the thin-walled portion is detected by a sensor chip fixed to the thin-walled portion of the sensing body, and an electric current from the sensor chip is detected. The signal is processed by the circuit board.

[0003]

The present inventors have further studied the above-mentioned conventional configuration, and have produced a pressure detecting device having the structure shown in FIG. This is fixed to a metal sensing body 2 having a pressure introducing hole 2a and a terminating end having a thin portion 2b, a metal housing 1 having a step portion 1e therein, and a thin portion 2b. A sensor chip 4 and a circuit board 7 that is adhesively fixed in the housing 1 and processes an electric signal from the sensor chip 4
A terminal assembly 10 electrically connected to an extraction electrode (post) 7c of the circuit board 7; a terminal assembly 10 in which the connector terminal 10a is integrally formed of resin; A connector case (11) is fixed to the housing (1) together with the assembly (10).

Here, when caulking is fixed by the caulking portion 1d of the housing 1, the caulking jig 13 is used to caulk the portion 1d.
Is applied with a load F. In this case, the performance required for the caulking portion 1d is to fix the connector case 11 so that the connector case 11 does not rotate with respect to the housing 1 when the connector is inserted or removed. When the connector rotates, for example, the adhesive portion between the housing 1 and the circuit board 7 is peeled off, and the circuit board 7 rotates, causing a problem such as disconnection of the wire 8.
Therefore, in order to avoid such a problem, a torque around the connector of 1 Nm or more is required. FIG.
(A) shows the relationship between the caulking load and the torque around the connector in the above configuration. From this figure, it can be seen that at least a caulking load of 5 kN or more is required to make the torque around the connector 1 Nm or more.

However, in the case of the configuration shown in FIG.
The portion of the connector case 11 to which the caulking load is applied is located above the corner of the step portion 1 e of the housing 1, and the terminal assembly 10 is not completely supported by the housing 1. 10 may be deformed. When the terminal assembly 10 is deformed in this way, the sealing becomes insufficient, or when the terminal assembly 10
In such a case, a problem arises that the joint portion is peeled off.

FIG. 14B shows the results of a study on the caulking load and the displacement D of the terminal assembly 10. As can be seen from this figure, the caulking load is 4KN.
As it gets larger, the terminal assembly 10 begins to deform. The range in which the sealing property is sufficient and the non-contact state with the wire 8 can be guaranteed is as follows.
It is desired that the displacement of 0 is 100 μm or less. Therefore, as can be seen from FIGS. 14A and 14B,
It becomes difficult to set conditions for increasing the torque around the connector to 1 N · m or more and for suppressing the displacement of the terminal assembly 10 to 100 μm or less.

In this case, the outer shape of the housing 1 may be increased so that the entire portion to which the caulking load is applied is securely supported by the housing 1. However, the outer shape of the housing is increased, and the pressure detecting device is reduced in size. Can not be converted. In addition, if an attempt is made to increase the caulking load in order to obtain a sufficient torque around the connector, the resin portion may be cracked.

SUMMARY OF THE INVENTION The present invention has been made in view of the above problems, and in a pressure detecting device for caulking and fixing a housing and a connector case, even if it has a caulking portion due to a relatively small caulking load without increasing the size, It is an object of the present invention to provide a pressure detecting device capable of securing a prescribed connector rotation torque.

[0009]

In order to achieve the above object, according to the first aspect of the present invention, there is provided a sensing device having a pressure introduction hole (2a) inside and a thin end (2b) at the end. A body member (1, 2) having a body part (2) and a housing part (1) which is outside the sensing body part (2) and has a step part (1e) inside and is attached to the object to be detected. ), A sensor chip (4) fixed to a side opposite to the pressure introduction side of the thin portion (2b) and outputting an electric signal according to a displacement of the thin portion (2b), and an inside of the housing portion (1). Which is electrically connected to the sensor chip (4) by a wire (8) to process an electric signal from the sensor chip (4), and is provided with an extraction electrode for electrically connecting to the outside. Circuit having (7c) A plate (7), said extraction electrode (7c) electrically connected to the connector terminal (1
0a), wherein the connector terminal (10a) is integrally formed of a resin.
And the O-ring (1) with the bottom surface of the terminal assembly (10) positioned on the step (1e).
A connector case (11) fixed to the housing together with the terminal assembly (10) via 2), wherein the connector case (11) has a portion (11a) to which a caulking load is applied; The portion (11a) is located above the corner of the step (1e), and the connector case (11) and the housing (1) have a concave portion or a convex portion and are caulked and fixed. It is characterized by being.

Therefore, even if the portion (11a) of the connector case (11) to which the caulking load is applied is located on the corner of the step (1e) of the housing (1),
The deformation of the terminal assembly (10) is suppressed, and the setting of the caulking load so as to satisfy the required value of the torque around the connector can be facilitated. Further, in the invention according to claim 2, the housing body (1, 2) having a recess, the circuit board (7) adhesively fixed in the recess of the housing body (1, 2), and the housing A sensor chip (4) arranged in the recess of the body (1, 2), a wire (8) for electrically connecting the circuit board (7) and the sensor chip (4), and a part of the wire to the outside A resin connector case (11) having exposed connector pins (11c).
1) The circuit board (7), the sensor chip (4), and the wire (8) are housed in the recess, and the connector pin (11c) is electrically connected to the sensor chip (4). The connector case (11) and the housing body (1) are caulked and fixed between the housing body (1, 2) so as to close the recess in a state where signal transmission with the outside is possible. ,
2) is a caulking auxiliary means (11b, 11b ', at least) for suppressing rotation of the connector case (11).
11b '' and 13a) and are caulked and fixed.

Therefore, even if the crimping portion has a relatively small caulking load without increasing the size,
The specified connector rotation torque can be secured. Further, as in the invention according to the third aspect, in the invention according to the second aspect, the caulking auxiliary means (11b, 11b ', 11
b '', 13a) are connected to the connector case (11) or the recesses (11b, 1
1b ′ and 11b ″) and the projection (13a).

The above-mentioned reference numerals in parentheses indicate the correspondence with specific means described in the embodiment described later.

[0013]

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a block diagram showing a first embodiment of the present invention. FIG. 1 shows a cross-sectional structure of a pressure detecting device according to an embodiment of the present invention. This pressure detector is
It measures the pressure of a high-pressure (for example, 20 MPa) fluid such as a fuel pressure of a fuel injection device and a brake oil pressure of a brake device in a vehicle.

In the figure, a housing 1 is made of a metal having good corrosion resistance and weldable (for example, SUS430), has a screw 1a, and is fixed to a not-shown object to be detected (for example, a fuel pipe) by screwing. It is supposed to be. The sensing body 2 is made of a metal having a low coefficient of thermal expansion and a low coefficient of thermal expansion (for example, a material having a linear thermal expansion coefficient close to that of silicon such as Kovar), has a pressure introducing hole 2a on the inside, and a pressure receiving hole 2a at its end. Thin portion 2b forming a diaphragm
Are formed. FIG. 2 shows the appearance of the sensing body 2. The sensing body 2 has a cylindrical shape, and a step portion 2c is formed at an end thereof, that is, a peripheral edge of a lower opening.

The sensing body 2 includes a housing 1
Of the housing 1, the step 2c thereof and the opening edge (end) 1b of the housing 1 abut against each other, and the portion is tightly fixed by electric welding or the like. In this way,
The sensing body 2 is assembled and fixed in the housing 1 to form a body as a housing body. In addition, since the housing 1 has the step portion 1b formed in the inner cavity of the screw 1a, when the sensing body 2 is assembled and fixed in the housing 1, an annular space is formed between the housing 1 and the sensing body 2. Gap 3 is formed.
The gap 3 can prevent the stress generated when the housing 1 is fixed to the detection target from being transmitted to the sensor chip 4.

A sensor chip 4 is joined to the upper surface of the thin portion 2b of the sensing body 2, that is, the surface opposite to the pressure introducing side, by a low-melting glass 5 which is an insulator. FIG. 3 shows a cross-sectional perspective view of a tip portion of the sensing body 2. As shown in the figure, four P-type diffusion gauges (strain gauges) 42a are provided on an N-type single crystal silicon substrate 41.
To 42d are formed to constitute the sensor chip 4. The strain gauges 42a to 42d are connected so as to form a bridge circuit, and output an electric signal according to the displacement of the thin portion 2b.

In FIG. 1, a step portion 1e is formed inside the housing 1, and a circuit board 7 is provided on the upper surface of the housing portion 1 in a storage area formed by the step portion 1e and the tip of the sensing body 2. Is stored and fixed. The circuit board 7 has a circuit section such as an amplifier circuit (including an adjustment circuit for adjusting the sensitivity of the sensor) that amplifies and outputs an electric signal from the sensor chip 4, and includes a multilayer ceramic substrate 7a and a circuit chip. 7b and post 7
c.

The multilayer ceramic substrate 7a is formed by printing and firing a conductive paste on the surface and the inner layer, and is fixed to the housing 1 with an adhesive. The circuit chip 7b is mounted on the multilayer ceramic substrate 7a,
The wire is electrically connected to a conductor (a partial region of the wiring) formed by firing the conductive paste of the multilayer ceramic substrate 7a. The post 7c serves as an extraction electrode for making electrical connection with the outside, and is made of, for example, 42 alloy, and is joined to the ceramic laminated substrate 7a by brazing or the like.

The conductor on the surface of the multilayer ceramic substrate 7a and the sensor chip 4 are electrically connected by wires 8 across the gap 3. The upper surfaces of the sensing body 2 and the multilayer ceramic substrate 7 (including the upper surface of the sensor chip 4 and the wires 8) are coated with a coating material (for example, silicone gel) 9 to prevent corrosion.

The post 7c joined to the ceramic laminated substrate 7a is connected to the connector terminal 10a of the terminal assembly 10 by electric welding or the like. The terminal assembly 10 includes a connector terminal 10a.
Is insert-molded with a resin such as PPS. The bottom surface of the terminal assembly 10 is located above the step 1e of the housing 1, and in this state, the O-ring 1
2 and a connector case 11 formed of a resin such as PPS having a connector pin 11c that is electrically connected to the sensor chip 4 to transmit a signal to the outside, and is fixed to the housing 1 by a caulking portion 1d of the housing 1. Have been.

Here, as shown in FIG. 4, a recess 11b
Are formed. Also, the caulking jig 13 has
3a is provided. Then, the convex portion 13a of the caulking jig 13 is aligned with the concave portion 11b of the connector case 11, and the caulking jig 13 is caulked and fixed by applying a load. In this case, since the swaged portion 1d of the housing 1 is dented in the concave portion 11b of the connector case 11, the torque around the connector is improved. These concave portion 11b and convex portion 1
3a corresponds to a caulking auxiliary means of the present invention.

FIG. 5 shows the relationship between the caulking load and the torque around the connector in that case. As can be seen from FIG. 14A, a large torque around the connector is obtained with a small caulking load. Therefore, similar to the one shown in FIG.
Even if a is located on the corner of the step portion 1e of the housing 1, it is possible to suppress the deformation of the terminal assembly 10 and satisfy the required value of the torque around the connector.
The setting of the caulking load can be facilitated.

FIG. 6 is an exploded sectional view of the main parts shown in FIG. 1, and FIGS. 7 to 10 show the steps of manufacturing them to assemble the pressure detecting device. In each of the process diagrams shown in FIGS. 7 to 10, (a) shows a top view and (b) shows a cross-sectional view. [Step in FIG. 7] First, a paste glass 5 is printed on the sensing body 2 and the sensor chip 4 is joined by firing. Next, the housing 1 is put on the sensing body 2, the sensing body 2 is press-fitted into the housing 1, and the end 1 b of the housing 1 and the step 2 of the sensing body 2
c, and the butted portion is tightly fixed by electric welding or the like. [Step of FIG. 8] Next, an adhesive is thinly and uniformly applied to the upper surface of the housing 1 around the sensing body 2 by a stamp or the like, and the multilayer ceramic substrate 7a on which the circuit chip 7b is mounted is set thereon. Bonding. Then, the conductor of the multilayer ceramic substrate 7a and the sensor chip 4 are electrically connected by ultrasonic bonding using wires 8. Thereafter, coating is performed with the coating material 9. [Step in FIG. 9] Next, the connector terminal 10a of the terminal assembly 10 and the post 7a of the multilayer ceramic substrate 7 are aligned and joined by electric welding or the like. [Step in FIG. 10] Thereafter, the connector case 11 and the O-ring 12 are set in the housing 1 and the caulking portion 1d of the housing 1 is swaged to seal and fix the inside of the connector case 11 and the housing 1. In this case, as shown in FIG. 4, the concave portion 11b of the connector case 11 and the convex portion 13a of the caulking jig 13 are aligned and caulked and fixed. Thus, the pressure detecting device shown in FIG. 1 is configured.

In the above-described embodiment, the case where one recess 11b is formed in the connector case 11 is shown. However, a plurality of recesses 11b may be formed, and instead of the recess 11b, FIG. The convex portion 11b 'shown in FIG. 11A or the beveled portion 11b''shown in FIG. 11B may be used. Further, the swaging portion 1d of the housing 1 may be formed in an uneven shape instead of the connector case 11 side. In short, when the connector case 11 and the housing 1 are caulked and fixed, if the projection-shaped portion of the concave portion or the convex portion is partially formed in the caulked and fixed portion, the torque around the connector can be improved. it can. The connector case 11 or the housing 1
All the concave and convex shapes provided in (1) correspond to the caulking auxiliary means of the present invention.

In the above embodiment, the semiconductor substrate 41
Although the sensor chip 4 is formed by forming the strain gauges 42a to 42d in FIG. 1, the sensor chip may be formed by forming a metal strain gauge on the insulating film by vapor deposition or the like. Further, in the above-described embodiment, the housing 1 and the sensing body 2 are configured as separate bodies. However, as shown in FIG.
May be integrally configured.

[Brief description of the drawings]

FIG. 1 is a sectional view of a pressure detecting device according to an embodiment of the present invention.

FIG. 2 is a diagram showing an external shape of a sensing body 2. FIG.

FIG. 3 is a partial cross-sectional perspective view showing a configuration of a sensing body 2 and a sensor chip 4.

FIG. 4 is a view showing an external shape of a connector case 11 and a caulking jig 13;

FIG. 5 is a diagram illustrating a relationship between a caulking load and a torque around the connector when the caulking is fixed in this embodiment.

FIG. 6 is an exploded sectional view of main components shown in FIG.

FIG. 7 is a diagram showing a step of manufacturing the pressure detecting device shown in FIG.

FIG. 8 is a view showing a step following the step shown in FIG. 7;

FIG. 9 is a view showing a step following the step shown in FIG. 8;

FIG. 10 is a view showing a step following the step shown in FIG. 9;

FIG. 11 is a view showing an external shape of a connector case 11 according to another embodiment of the present invention.

FIG. 12 is a cross-sectional view of a pressure detecting device according to another embodiment of the present invention.

FIG. 13 is a cross-sectional view showing a configuration of a pressure detecting device previously manufactured by the present inventors.

14 is a diagram showing a relationship between a caulking load and a torque around a connector and a relationship between a caulking load and a displacement amount of a terminal assembly in the pressure detection device shown in FIG. 13;

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Housing, 1e ... Step part, 2 ... Sensing body, 2a ... Pressure introduction hole, 2b ... Thin part, 3 ... Gap, 4 ...
Sensor chip, 5 ... low melting point glass, 7 ... circuit board, 8 ...
Wire, 9: coating material, 10: terminal assembly, 10a: connector terminal, 11: connector case, 11b: concave portion, 12: O-ring, 13: caulking jig.

Claims (3)

[Claims] 1. A sensing body (2) having a pressure introducing hole (2a) inside and a thin end (2b) at the end, and a sensing body (2) outside and inside the sensing body (2). A housing part (1) having a stepped part (1e) and attached to the object to be detected.
2) a sensor chip (4) fixed to the opposite side of the thin portion (2b) from the pressure introduction side and outputting an electric signal according to the displacement of the thin portion (2b); The sensor chip (4) is fixed inside and is electrically connected to the sensor chip (4) by a wire (8) to process an electric signal from the sensor chip (4). A terminal having a circuit board (7) having an electrode (7c) and a connector terminal (10a) electrically connected to the extraction electrode (7c), wherein the connector terminal (10a) is integrally formed of resin. An O-ring (12) with the bottom of the assembly (10) and the terminal assembly (10) positioned on the step (1e);
The connector case (1) which is caulked and fixed to the housing together with the terminal assembly (10) via
The connector case (11) has a portion (11a) to which a caulking load is applied, and the portion (1) to which the caulking load is applied.
1a) is located on a corner of the step (1e), and the connector case (11) and the housing (1).
Is a pressure detection device characterized by having a concave portion or a convex portion and being caulked and fixed. 2. A housing body (1, 2) having a recess.
A circuit board (7) adhesively fixed in the recess of the housing body (1, 2); a sensor chip (4) arranged in the recess of the housing body (1, 2); A wire (8) for electrically connecting the circuit board (7) and the sensor chip (4); and a resin connector case (11) having connector pins (11c) partially exposed to the outside, The connector case (11) accommodates the circuit board (7), the sensor chip (4), and the wire (8) in the recess, and the connector pin (11).
c) and the sensor chip (4) are caulked and fixed between the housing body (1, 2) so as to close the recess in a state where the sensor chip (4) is electrically connected to allow signal transmission to the outside. The connector case (11) and the housing body (1, 2) are at least connected to the connector case (11).
Assisting means (11b, 11b) for suppressing the rotation of
b ', 11b'', 13a), and are caulked and fixed. 3. The caulking auxiliary means (11b, 11
b ′, 11b ″, and 13a) correspond to the connector case (1).
1) or concave portions (11b, 11b ′, 11b ″) and convex portions (13) provided in the housing body (1, 2).
The pressure detecting device according to claim 2, wherein a) is satisfied.