JPH06281519A - Pressure sensor - Google Patents

Abstract

PURPOSE:To reduce the size of sensor and lower the cost by combining the connector inserted by a terminal and the cover and fixing a capacitor to the cover after soldering on a shield cover. CONSTITUTION:A connector 18 formed by inserting a terminal 17 and a cover 16 are combined in one and a capacitor 20 is soldered on a shield cover 19 and then fixed to the cover 16. A base plate 21 fixed with a pressure sensing element 22 and an overlapping electronic circuit 23 with the use of a long lead 23a and a base 24 containing a filter 25 are fixed to the cover 16. When pressure from a measured object reaches a diaphragm having the pressure sensing element 22 through the medium, the filter 25 and a pressure introduction part 26, the diaphragm is distorted, the balance of the bridge resistors formed on the diaphragm is lost to generate a resistance difference. This is converted to voltage to transmit to the electronic circuit 23, amplified and temperature- compensated there, and the output is transmitted to the terminal and a computer, etc.

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 measuring the pressure of gas or liquid.

[0002]

2. Description of the Related Art FIG. 3 is a sectional view of a conventional pressure sensor disclosed in, for example, Japanese Utility Model Laid-Open No. 4-64741, and FIG. 4 is a top view of FIG. In the figure, 1 is a terminal electrically connected to the outside, 2 is a connector that includes the terminal 1 and is mechanically connected to an external connector (not shown), and 3 is a capacitor that cuts out radio wave noise from the outside, Soldered to the shield plate 4 and the terminal 1. Reference numeral 5 is, for example, a pressure sensitive element using a piezoresistive effect by a semiconductor 6, an electronic circuit (HIC) 7 having a function of amplifying an output signal of the pressure sensitive element 6 and further performing temperature compensation, and shielding radio wave noise from the outside. A board on which a shield cover 8 and the like are mounted is connected to the terminal 1 by a soldering portion 9. Reference numeral 10 is a pressure introducing portion, that is, a nipple of the pressure sensitive element 6, 11 is an O-ring for sealing between the nipple 10 portion and the cup 12, and 13 is between the cup 12 and the base 14 integrated with the terminal 1 and the connector 2. The inserted filter, 15 is the pressure sensitive element 6, the electronic circuit 7, the substrate 5
A cover that protects the like and is fixed to the base 14.

Next, the operation will be described. Filter 13
The pressure transmitted to the pressure sensitive element 6 through the strain distorts the diaphragm in the pressure sensitive element 6, which utilizes, for example, the semiconductor piezoresistive effect, and transmits a resistance value change corresponding to the strain amount to the electronic circuit 7. Therefore, the temperature is compensated so that it can be amplified several tens of times and can be accurately measured even in a wider temperature range. The change in the output voltage according to the pressure is transmitted to an external device (not shown) such as a computer through the terminal 1 in the connector 2.

[0004]

Since the conventional pressure sensor is constructed as described above, the area of the pressure sensitive element 6 and the electronic circuit 7 occupied on the substrate 5 becomes large, and therefore the shield cover 8 is large. In addition to the shape, the shield plate 4 for soldering the capacitor 3 is required, and the outer shape is increased, and at the same time, the cost is increased.

The present invention has been made to solve the above problems, and an object thereof is to obtain a pressure sensor which can be downsized and at the same time cost reduced.

[0006]

In a pressure sensor according to the present invention, a connector having a terminal inserted and a cover are integrated, a capacitor is soldered to a shield cover and then fixed to the cover, and a pressure sensitive element and an electronic circuit are provided. The substrates mounted in layers are fixed to the cover, and the base with the built-in filter is fixed to the cover.

[0007]

In the pressure sensor of the present invention, the pressure-sensitive element and the electronic circuit are superposed on each other and mounted on the substrate to integrate the connector with the cover, whereby the pressure sensor is downsized and the cost is reduced.

[0008]

【Example】

Example 1. An embodiment of the present invention will be described below with reference to FIGS. 1 is a sectional view, and FIG. 2 is a view of FIG. 1 seen from above. In the figure, 16 is a cover integrated with a connector 18 in which a terminal 17 is insert-molded, and 19 is a shield cover to which a capacitor 20 is soldered, which is fixed in the cover 16. Reference numeral 21 denotes a substrate on which a pressure-sensitive element 22 and an electronic circuit (HIC) 23 using long leads 23a are stacked and mounted, and soldered 21a to the terminal 17. Reference numeral 24 denotes a base having a filter 25 built therein, which is fixed to the cover 16.

Next, the operation will be described. When the pressure medium to be measured reaches the not-shown diaphragm of the pressure-sensitive element 22 through the filter 25 from the pressure introducing portion 26, the diaphragm is distorted and the four bridges formed on the diaphragm are distorted. -Shaped resistance is out of balance, resulting in a resistance difference. This is voltage-converted and transmitted to the electronic circuit 23, where it is amplified and temperature-compensated and transmitted from the terminal 17 to a computer (not shown) as a change in the output voltage. Further, the capacitor 20 shields radio wave noise coming from the terminal 17 and the shield cover 19 shields external radio wave noise, respectively, and protects the pressure sensor so as to function normally.

When the pressure-sensitive element 22 and the electronic circuit 23 are stacked and mounted on the substrate 21 as described above, the overall volume becomes 2/3 and the weight becomes 2/3 as compared with the conventional type. The size can be reduced and the cost can be reduced at the same time.

Embodiment 2. Although the electronic circuit 23 is mounted above the pressure sensitive element 22 in the above embodiment, the pressure sensitive element 22 may be provided above the electronic circuit 23. The same applies when the filter 25 is not provided. Further, in the above-described embodiment, the case of the pressure sensor has been described, but the same effect as that in the above-described embodiment can be obtained even if another sensor such as an acceleration sensor or a current sensor is used.

[0012]

As described above, according to the present invention, the pressure sensitive element and the electronic circuit are mounted on the substrate in an overlapping manner, and the connector and the cover are integrally structured and the shield cover is fixed to the cover. Therefore, it is possible to obtain the effect that the device has a shape that is ⅔ of that of the conventional product, is small, and is inexpensive.

[Brief description of drawings]

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

FIG. 2 is a view of FIG. 1 seen from above.

FIG. 3 is a cross-sectional view showing a conventional pressure sensor.

FIG. 4 is a view of FIG. 3 seen from above.

[Explanation of symbols]

 16 Cover 17 Terminal 18 Connector 19 Shield Cover 20 Capacitor 21 Board 22 Pressure Sensitive Element 23 Electronic Circuit 24 Base 25 Filter

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[Procedure amendment]

[Submission date] August 5, 1993

[Procedure Amendment 1]

[Document name to be corrected] Drawing

[Name of item to be corrected] Figure 3

[Correction method] Change

[Correction content]

[Figure 3]

[Procedure Amendment 2]

[Document name to be corrected] Drawing

[Name of item to be corrected] Figure 4

[Correction method] Change

[Correction content]

[Figure 4]

Claims (1)

[Claims] 1. A cover integrated with a connector into which a terminal is inserted, a shield cover fixed to the cover and soldered with a capacitor, and a pressure-sensitive element and an electronic circuit which are soldered to the terminal and overlap each other. A pressure sensor, comprising: a substrate mounted on the cover; and a base fixed to the cover and having a built-in filter.