JPH0654271B2 - Semiconductor pressure sensor - Google Patents

Description

Description: FIELD OF THE INVENTION The present invention relates to an improvement of a semiconductor pressure sensor suitable as, for example, an automobile engine manifold pressure detector.

[Background of the Invention]

JP-A-55-103438 is known in relation to this type of semiconductor pressure sensor. FIG. 3 is a sectional view of a conventional semiconductor pressure sensor, and FIG. 4 is a bottom view of the vicinity of the connector portion and the lock portion of FIG. In the figure, 1 is a semiconductor strain gauge, 2 is a plastic housing, 3 is a thick film circuit board, 4 is an air introduction hole provided in the plastic housing 2, 5 is a connector portion, 6 is a cap of the strain gauge 1 housing portion, 7 Is a lock portion of the direct insertion connector portion, and is formed by projecting integrally with the plastic housing together with the connector portion 5. 8 is an adhesive for fixing the storage portion of the strain gauge 1 to the plastic housing 2, 9 is a chip amplifier (CCB chip), 10 is a chip capacitor, 11 is a connecting pad, and each is connected to the thick film circuit board 3 by the solder 12. ,
The thick film circuit board 3 is fixed to the plastic housing 2 with an adhesive 8.

Reference numeral 13 is an atmosphere-conducting hole of the cap 6, 14 is a nickel wire for connecting the strain gauge 1 and the connecting pad 11, and 15 is an electronic component such as a connecting pad 11, a chip capacitor 10 and a CCB chip 9 on the thick film circuit board 3. Resin injected to cover and protect the. Reference numeral 16 denotes a terminal terminal, one end side of which is projected into the connector portion 5 having a substantially oval cross section and the other end side of which is projected and molded into the plastic housing 2 when the plastic housing 2 is molded. Space 20 on the upper surface of the lead frame 17 and the resin 15 which are soldered to the thick film circuit board 3 inside
It is electrically connected by spot welding. Reference numeral 18 is a pressure introducing pipe for the strain gauge 1, and 21 is a lid.

Then, when the pressure P ₁ is applied from the pressure introducing pipe 18,
The pressure P ₁ causes strain in the strain gauge 1 and is changed into an electric current, that is, the pressure P ₁ is converted into an electric signal, and this electric signal is transmitted to the thick film circuit board 3 by the nickel wire 14 and is transmitted by the CCB chip 9. The amplified signal is taken out through the lead frame 17 and the terminal terminal 16 and transmitted to the control unit or the like. The protruding portion of the lock portion 7 is adapted to be fitted and fixed to a mating concave portion (not shown), and the male coupler is to be inserted into the connector portion 5.

In the above structure, the lock portion 7 is provided with the air introduction hole 4, and the air introduction hole 4 is an absolutely indispensable structure because the relative pressure type strain gauge 1 based on the atmospheric pressure is adopted. The electrically conductive portion of the connector portion 5 is covered with the protruding portion of the oval connector portion 5 and is waterproof, but the atmosphere introducing hole 4 provided in the lock portion 7 is waterproof. Since water does not enter because water pressure is directly applied when running, etc., the terminal terminal 16 and the lead frame 1
The connecting portion 7 is exposed in the space 20, and there is a drawback that electrolytic corrosion occurs inside the pressure sensor, that is, in the thick film circuit board 3. The defect that water drops enter the air introduction hole and enter the inside of the sensor is apparent by conducting a water resistance test, JIS DO203, SI × 30 minutes.

[Object of the Invention]

The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a semiconductor pressure sensor that can improve the water resistance without entering water into the sensor and can increase the degree of freedom of the mounting location. is there.

[Outline of Invention]

The semiconductor pressure sensor of the present invention is a hybrid thick film circuit board in which a semiconductor strain gauge for converting an external pressure into an electric signal, a chip amplifier for amplifying the output of the strain gauge, and a chip capacitor are attached and the upper surface is covered with a resin. And a plastic housing in which the above-mentioned strain gauge is built-in and a space is formed on the upper surface of the resin and the above-mentioned strain gauge and which is covered with a lid, and a terminal terminal which is fixedly secured to the plastic housing and is projected and electrically connected to the outside. A direct insertion connector portion and a lock portion, and an atmosphere introduction hole that is provided inside the lock portion and communicates with the space to form a reference pressure of the strain gauge, and is provided in a protruding height direction of the lock portion. A waterproof wall is provided so as to surround the atmosphere introducing hole together with the lock portion.

Example of Invention

Hereinafter, the semiconductor pressure sensor of the present invention will be described with reference to the embodiments, the same parts as those of the conventional one will be denoted by the same reference numerals, and description of the structure of the same parts will be omitted.
This will be described with reference to FIGS. FIG. 1 is a bottom view of the vicinity of the connector part and the lock part of FIG. 3, and FIG. 2 is a front view of FIG. In the figure, reference numeral 1 denotes a waterproof wall, which is a connector portion 5 projectingly formed on the plastic housing 2.
Is formed integrally with the plastic housing 2 at the same height as the lock portion 7 so as to surround the entire circumference of the atmosphere introducing hole 4 together with the lock portion 7. Therefore, since one end face side of the air introduction hole 4 is opened by the waterproof wall 19 but the entire circumference is covered, the water is not directly applied to the space 20 from the air introduction hole 4. Water can be prevented from entering. The waterproof wall 19 provided almost all around the connector portion 5 does not interfere with the attachment and detachment of the male coupler.

As described above, in the semiconductor pressure sensor of the present embodiment, the waterproof wall having the same height as the lock portion is integrally formed on the entire circumference of the connector portion so as to surround the lock portion and the atmosphere introduction hole from the plastic housing. As a result, it is possible to prevent water pressure from being directly applied to the air introduction hole, and thus to prevent water from entering the sensor, preventing electrolytic corrosion from occurring in the thick film hybrid circuit, and making it environmentally resistant. In particular, it has excellent water resistance and can improve reliability. Further, since it is excellent in water resistance, even when it is mounted in the engine room, the degree of freedom of the mounting position can be improved without limiting the mounting place to a narrow range.

In the above embodiment, the case where the waterproof wall 19 is provided so as to surround the outside of the oval portion of the connector portion has been described. However, the connector of the portion facing the lock portion without enclosing the outside of the elliptical portion is provided. Even if a waterproof wall is provided so as to surround the atmosphere introducing hole by using the above-mentioned part, the same operation and effect can be obtained.

〔The invention's effect〕

As described above, the semiconductor pressure sensor of the present invention has an effect that the water resistance can be improved without the intrusion of water into the inside of the sensor and the degree of freedom of the mounting place can be increased.

[Brief description of drawings]

FIG. 1 is an embodiment of the semiconductor pressure sensor of the present invention, and is a bottom view of the vicinity of the connector portion and the lock portion of FIG.
2 is a front view of FIG. 1, FIG. 3 is a cross-sectional view of a conventional semiconductor pressure sensor, and FIG. 4 is a bottom view of the vicinity of the connector portion and the lock portion of FIG. 1 ... Strain gauge, 2 ... Plastic housing, 3 ...
… Thick film circuit board, 5 …… Connector part, 7 …… Lock part,
9: Chip amplifier, 10: Chip capacitor, 15
...... Resin, 16 ...... Terminal terminals, 19 ...... Waterproof wall, 20 ...... Space, 21 ...... Lid.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Shinichi Yamaguchi 3085 Higashiishikawa Nishikonai, Katsuta City, Ibaraki Prefecture 5 Ritsudoku Automotive Engineering Co., Ltd. (56) Reference JP-A-55-103438 (JP, A) Actual Open Sho 59-47838 (JP, U) Actual Open Sho 61-122543 (JP, U)

Claims (2)

[Claims] 1. A mixed thick film circuit board having a semiconductor strain gauge for converting an external pressure into an electric signal, an amplifier for amplifying the output of the strain gauge, and the strain gauge built-in, and a space is provided on the upper surface of the strain gauge. A plastic housing formed and covered with a lid, a direct-insertion connector portion and a lock portion, which are provided in the plastic housing and projecting from the plastic housing and electrically connected to the outside, and a lock portion; In the one provided with an atmosphere introducing hole that communicates with the space and forms the reference pressure of the strain gauge, a waterproof wall is provided so as to surround the atmosphere introducing hole with the lock portion in the protruding height direction of the lock portion. A semiconductor pressure sensor characterized by being provided. 2. The semiconductor pressure sensor according to claim 1, wherein the waterproof wall is formed at the height of the lock portion so as to surround the outer periphery of the connector portion together with the lock portion.