JPS61226625A - Semiconductor pressure sensor - Google Patents

Abstract

PURPOSE:To improve water resistance without the invasion of water into the sensor by providing the wall for water-proof so as to surround the circumference of the air introducing hole together with the locking part in the projected height direction of the locking part. CONSTITUTION:A wall 19 for water-proof is formed by molding in a single body with a plastic housing 2 at the same height as the locking part 7 so as to surround the circumference of an air introducing hole 4 together with the locking part 7 at the whole circumference of a connector part 5 projected and formed to a plastic housing 2. Consequently, the air introducing hole 4 is opened at one edge surface side by the wall for water-proof, other whole circumference is covered, and therefore, the water pressure is not loaded directly and the invasion of the water in a space 20 from the air introducing hole 4 can be prevented.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Application of the Invention] The present invention relates to an improvement in a semiconductor pressure sensor suitable as, for example, an engine manifold pressure detector for an automobile.

[Background of the invention]

Regarding this kind of semiconductor pressure sensor, Japanese Patent Application Laid-Open No. 55-1034
38 are known. 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 lock portion of FIG. 3. In the figure, 1 is a semiconductor strain gauge, 2 is a plastic housing, 3 is a thick film circuit board, and 4
is the atmosphere introduction hole provided in the plastic housing 2,
5 is the connector part, 6 is the cap of the strain gauge l storage part, 7
1 is a locking portion of the direct-insertion connector portion, which is integrally molded with the plastic housing and protrudes together with the connector portion 5. 8 is the adhesive that fixed the storage part of the strain gauge 1 to the plastic housing 2, and 9 is the chip amplifier (CCB).
chip), 10 is a chip capacitor, 11 is a connection bat, and each is connected to the thick film circuit board 3 by solder 12, and the thick film circuit board 3 is connected to the thick film circuit board 3 by adhesive 8.
Fixed to Uzing 2.

13 is an atmospheric conduction hole in the cap 6, 14 is a nickel wire that connects the strain gauge 1 and the connection plate 11, and 15 is an electronic wire such as the connection pad 11 on the thick film circuit board 3, the chip capacitor 10, and the CCB chip 9. A resin injected to cover and protect parts.

Reference numeral 16 denotes a terminal terminal, which has a roughly oval cross section and has one end protruding into the protruding connector portion 5, and the other end thereof is protruded into the plastic housing 2 when the plastic housing 2 is molded, and the plastic housing 2
Inside, the thick film circuit board 3rc is connected by spot welding to the lead frame 17 connected by soldering and the space 20 above the resin 15 in a spot welding manner. A pressure introduction pipe for the 18Fi strain gauge l, 21 is a lid, and when pressure P1 is applied from the pressure introduction pipe 18,
The pressure PI causes strain in the strain gauge l and is changed into a current, that is, the pressure P1 is converted into an electrical signal, and this electrical signal is transmitted to the thick film circuit board 3 through the nickel wire 14 and amplified by the CCB step 9. The signal is taken out to the outside via the lead frame 17 and the terminal terminal 16 and transmitted to a control unit or the like. The protruding portion of the lock portion 7 is fitted into a mating recess (not shown), and a male coupler is inserted into the connector portion 5.

In the above structure, the lock part 7 is provided with an atmosphere introduction hole 4, and the atmosphere introduction hole 4 is an absolutely essential structure because it uses a relative pressure type strain gauge l based on atmospheric pressure. . 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 air introduction hole 4 provided in the lock portion 7 is not waterproof. Therefore, water pressure is directly applied during driving, etc., and water does not enter the terminal terminal 16 and lead frame 17.
There is a drawback that the connecting portion of the pressure sensor is exposed in the space 20, and electrolytic corrosion occurs inside the pressure sensor, that is, the thick film circuit board 3.

The drawback of water droplets entering the air inlet hole and entering the inside of the sensor becomes clear by conducting a water resistance test for 30 minutes.

[Purpose of the invention]

The present invention was made in view of the above situation, and an object of the present invention is to provide a semiconductor pressure sensor that can improve water resistance without water intrusion into the sensor, and can increase the degree of freedom in mounting location. It is.

[Summary of the invention]

The semiconductor pressure sensor of the present invention includes a semiconductor strain gauge that converts external pressure into an electrical signal, a chip amplifier that amplifies the output of the strain gauge, and a hybrid thick film circuit board that is equipped with a chip capacitor and whose upper surface is covered with resin. and a plastic housing containing the strain gauge and having a space formed above the resin and the strain gauge and covered with a lid, and a built-in terminal terminal that is fixed to and protrudes from the plastic housing and is electrically connected to the outside. A direct plug connector portion and a lock portion are provided, and an atmosphere introduction hole is provided inside the lock portion and communicates with the space to form a reference pressure of the strain gauge. A waterproof wall is provided to surround the air introduction hole and the lock portion.

[Embodiments of the invention]

Hereinafter, the semiconductor pressure sensor of the present invention will be explained using an embodiment, referring to FIGS. 1 and 2, in which the same parts as those in the conventional art are denoted by the same reference numerals, and the explanation of the structure of the same parts will be omitted. 1 is a bottom view of the vicinity of the same parts as the connector section and lock section of FIG. 3, and FIG. 2 is a front view of FIG. 1. In the figure, reference numeral 19 denotes a waterproof wall, and the connector portion 5 is formed protruding from the plastic housing 2.
It is integrally formed with the plastic housing 2 at the same height as the lock part 7 so as to surround the atmosphere introduction hole 4 together with the lock part 7 on the entire circumference. Therefore, one end side of the air inlet hole 4 is opened in the waterproof wall 19, but the other entire circumference is covered, so water pressure is not applied directly and the air inlet hole 4 flows into the space 20. can prevent water from entering. It should be noted that the waterproof wall 19 provided around the entire circumference of the connector portion 5 does not impede attachment and detachment of the male coupler at all.

In this way, the semiconductor pressure sensor of this embodiment has a waterproof wall that is integrally molded with the lock part and has the same height as the lock part so as to surround the atmosphere inlet hole and protrude from the plastic housing all around the connector part. Because it can prevent
It can prevent electrolytic corrosion from occurring in thick film hybrid circuits, has excellent environmental resistance, especially water resistance, and can improve reliability. 19. Excellent water resistance. 9. Even when installed in the engine room, the installation location is not limited to a narrow range, and the degree of freedom in the installation location can be improved.

In the above embodiment, the case where the waterproof wall 19 is provided so as to surround the outside of the oval part of the connector part has been described. The effect is the same even if a waterproof wall is provided to surround the air inlet hole. □ [Effects of the Invention] As described above, the semiconductor pressure sensor of the present invention has the effect of being able to improve water resistance without water infiltrating inside the sensor, and increasing the degree of freedom in mounting location.

[Brief explanation of the drawing]

FIG. 1 shows an embodiment of the semiconductor pressure sensor of the present invention, and is a bottom view of the vicinity of the same parts as the connector section and lock section of FIG. 3;
2 is a front view of FIG. 1, 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 lock portion of FIG. 3.

Claims (2)

[Claims] 1. A semiconductor strain gauge that converts external pressure into an electrical signal, a chip amplifier that amplifies the output of the strain gauge, and a hybrid thick film circuit board whose top surface is coated with resin and has a chip capacitor attached thereto, and a built-in strain gauge. A plastic housing with a space formed on the upper surface of the strain gauge and covered with a lid, a direct plug connector part and a lock part that have built-in terminal terminals that are fixed to and protrude from the plastic housing and are electrically connected to the outside. and an atmosphere inlet hole provided inside the lock part and communicating with the space to form the reference pressure of the strain gauge, wherein the periphery of the atmosphere inlet hole is provided in the direction of the protruding height of the lock part. A semiconductor pressure sensor characterized in that a waterproof wall is provided to surround the lock portion. 2. 2. The semiconductor pressure sensor according to claim 1, wherein the waterproof wall is formed at a height of the lock portion so as to surround the outer periphery of the connector portion together with the lock portion.