JPH07311108A - Sealing structure of electronic device - Google Patents

Abstract

PURPOSE:To make the incorporation of an O-ring into a case easier so that perfect sealing is obtained without dismounting by forming the accommodation gap of the O-ring as it extends toward an open part and making the tip of a spacer come into the gap. CONSTITUTION:A gap 31 between a cylindrical surface 20a formed at the bottom of a connector 20 and the internal periphery surface of a case 18 is formed so that it extends toward an open part. A ring-like projecting part 26' a comes into the gap 31, and an O-ring 30 is pressed up from under with the plane formed at its tip. With this, since the open part of the case 18 is set so that it faces upward at incorporation so that the ring 30 is dropped into it, the ring 30 comes into the gap 31. Then, a spacer 26' is dropped in, and by applying external force with the projecting part 26' a, the ring 30 contacts with the internal peripheral surface of case 18, the entire peripheral surface of circular clamping part at the bottom of the connector 20, and the flat surface of the projecting part 26'a, three surfaces in all, so that sealing characteristic is assured.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a seal structure for an electronic device used for measuring the pressure of engine oil for automobiles.

[0002]

2. Description of the Related Art A seal structure for a pressure sensor, which is one of the electronic devices currently under development, will be described with reference to FIG. That is, 1 is a pressure sensor element as shown in FIG. 4, and this pressure sensor element 1 has a cylindrical case 2 which internally protects a semiconductor diffusion strain gauge (not shown).
And a flange 3 formed around the cylindrical case 2.
And the pressure introducing pipe 4 and the lead pin 5 which are spent from the cylindrical case 2.

Further, in FIG. 3, reference numeral 6 denotes a disk-shaped holder for protecting the pressure sensor element 1, and a through hole for inserting the pressure introducing pipe 4 is formed in the center of the holder 6. Has been done.

Reference numeral 10 denotes a frame member which is superposed on the upper side of the holder 6, and a through hole 11 into which the pressure introducing pipe 4 of the pressure sensor element 1 is fitted, and a fixing screw 12 in the central portion of the frame member 10. Each of the insertion holes 13 is formed. A terminal 14 connected to the lead pin 5 of the pressure sensor element 1 is embedded in the frame member 10. Reference numeral 35 denotes a pressing member that is stacked on the upper side of the frame member 10, and has a through hole 36 into which the cylindrical case 2 of the pressure sensor element 1 is inserted and an insertion hole 37 of the fixing screw 12 formed in the center thereof. There is.

Reference numeral 16 is a stem having a pressure introducing hole 17 in the central portion, 18 is a case fitted on the upper side of the stem 16, and an outer connecting terminal 19 is fixed through the outer upper end portion of the case 18. The connector portion 20 is formed integrally with the case 18.

Reference numeral 21 is a circuit board, and 22 and 23 are stems 1.
6 and the pressure introducing pipe 4, a sealing material and an O-ring, 24 is an O-ring interposed between the stem 16 and the case 18, 25 is a circuit pattern on the circuit board 21, and an external connection terminal 19 Is a conductive spring that electrically conducts between and, and this spring 25 is inserted and held in a through hole 27 formed in a spacer 26 that is fitted over the front frame member 10. ing.

The case 18 having the above structure,
Next, a structure for improving waterproofness between the case 18 and the connector portion 20 insert-molded on the top surface thereof will be described. In this prior art example, a through-hole 29 for penetrating the external connection terminal 19 is bored in the top surface of the inverted cup-shaped metallic case 18 to integrally form a connector portion 20 integrated with the metallic case 18. In doing so, insert molding of the connector portion 20 with the external connection terminal 19 penetrating the through hole 29 is performed, insert molding of the connector portion 20 is further performed, and the inner peripheral surface of the metal case 18 and insert molding are performed. The waterproof property inside the case 18 is further enhanced by the action of the O-ring 30 for sealing between the connector 20 and the connector 20.

Next, the assembly and operation of the above structure will be described. The frame member 10 to which the pressure sensor element 1 is fixed is fixed onto the stem 16. At the time of this fixing, the sealing material 2 is inserted into the pressure introducing hole 17 provided in the stem 16.
After the 2 and the O-ring 23 are fitted, the pressure introduction pipe 4 of the pressure sensor element 1 held by the frame member 10 is airtightly inserted into the center hole of the sealing material 22 and the O-ring 23. After that, the frame member 10 and the pressing member 35
The mounting screw 12 penetrating through is screwed into the stem 16 to fix the pressure sensor element 1, the frame member 10, and the pressing member 35 on the stem 16.

Next, the circuit board 21 is placed on the frame member 10. As a result, the lead pin 5 of the pressure sensor element 1 and the circuit pattern provided on the circuit board 21 are electrically connected. After that, the circuit board 2
A spacer 26 is placed in a fixed position on the frame member 10 from above 1, and then a conductive spring 25 is inserted into a through hole 27 provided in the spacer 26 and installed. Further, cover the case 18 having the connector 20 from the upper part thereof,
The pressure sensor is constructed by swaging the lower end opening edge of the above to the collar portion of the stem 16 and sealing it.

[0010]

However, in the conventional seal structure for an electronic device such as a pressure sensor as described above, the upper end surface of the spacer 26 and the lower end surface of the connector portion 20 are in contact with each other, and the O-ring is formed. Since the structure for preventing the separation of the space 30 from the gap 31 is used, for example, when the height dimension of any one of the spacer 26 and the frame member 10 is short due to defective molding or the like, or the case 18 and the stem 16.
If the caulking between and is loose, the spacer 2
Since the upper end surface of 6 and the lower end surface of the connector portion 20 do not contact each other and a gap is formed, the O-ring 30 may be separated from the gap 31 and the sealing function may not be exhibited.

A gap 31 for accommodating the O-ring 30 is also provided.
Since the cross-sectional shape of No. 1 is rectangular, when assembling the O-ring 30, it is necessary to push it in using a jig or the like.
The problem was that workability was poor.

Therefore, an object of the present invention is to provide a seal structure for an electronic device which has a good workability of assembling an O-ring and a good sealability.

[0013]

In order to achieve the above object, a seal structure for an electronic device according to the present invention has a lower case for housing the electronic device and a housing for a connector portion through which a terminal connected to the electronic device penetrates. In an electronic device comprising an upper case in which an upper wall surface is sandwiched by a pair of upper and lower cylindrical sandwiching portions formed in the above, an outer peripheral surface of the cylindrical sandwiching portion on the lower side of the connector portion and an inner periphery of the lower case The gap formed between the surface and the surface is set so that its size gradually widens toward the opening, and the tip plane is formed with a ring-shaped convex portion having a size smaller than the opening size of the gap. A pressing member provided on the lower case side is provided, and when the upper case is assembled to the lower case, the tip portion of the ring-shaped convex portion enters into the gap, and the O-ring is attached to the tip portion. And the surface, and the inner peripheral surface of the upper case and the structure sandwiched by three surfaces of the lower circular clamping portion of the peripheral surface of the connector portion.

[0014]

In the seal structure of the electronic device constructed as described above, since the space for accommodating the O-ring is formed so as to widen toward the opening, it is easy to insert the O-ring. Also, since the tip of the spacer enters the gap, the O-ring will not come off.

[0015]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The structure will be described with reference to FIGS. In FIGS. 1 and 2, the same or equivalent components as those shown in FIGS. 3 to 4 are designated by the same reference numerals, and the description of only different portions will be omitted.

That is, in FIGS. 1 and 2, the cylindrical surface 20a formed at the lower end of the connector 20 and the case 18 are
The gap 31 between the inner peripheral surface of the
That is, it is formed so as to widen toward the opening. The spacer 26 'is the spacer 26 in FIG.
On the other hand, the convex portion 26 'is formed over the entire periphery of the upper end surface
a is formed, and the ring-shaped convex portion 26'a enters into the gap 31 and becomes O in a plane formed at the tip.
Push the ring 30 up from below.

As a result, the opening of the case 18 is set upward during assembly, and the O-ring 30 is placed therein.
Since the O-ring 30 is inserted into the gap 31, the spacer 26 'is then dropped, and an external force is applied by the ring-shaped convex portion 26'a, the O-ring 30 is attached to the inner peripheral surface of the case 18 and the connector portion 20. The entire peripheral surface of the circular sandwiching portion at the lower end and the flat surface of the convex portion 26'a of the spacer 26 'come into contact with each other, and the sealing performance is secured.

[0018]

As described above, according to the present invention, the O-ring can be very easily incorporated into the case, and the O-ring can be reliably sealed without being detached.

[Brief description of drawings]

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

FIG. 2 is an explanatory view of a main part for explaining the present invention.

FIG. 3 is an explanatory view of a sectional structure of a conventional pressure sensor.

4 is a perspective view of the pressure sensor element 1 in FIG.

[Explanation of symbols]

 1 Pressure Sensor Element 3 Flange 4 Pressure Introducing Pipe 6 Holder 10 Frame Member 16 Stem (Lower Case) 17 Pressure Introducing Hole 18 Case (Upper Case) 20 Connector Part 21 Circuit Board 23, 24, 30 O-ring 25 Conductive Spring 26, 26 'Spacer 26'a Ring-shaped convex portion 31 Gap 35 Holding member

Claims (1)

[Claims] 1. A lower case (16) for housing an electronic device (1) and a terminal (1) connected to the electronic device (1).
An electronic device comprising an upper case (18) in which an upper wall surface is sandwiched by a pair of upper and lower cylindrical clamping portions formed in a housing of a connector portion (20) through which the connector portion (20) penetrates. The gap (31) formed between the circumferential surface of the lower cylindrical sandwiching portion and the inner circumferential surface of the upper case (18) is set so that its dimension gradually widens toward the opening. Further, a ring-shaped convex portion (26'a) having a plane of the tip portion smaller than the opening dimension of the gap (31) is formed, and a pressing member (26 ') provided on the lower case (16) side is provided, When the upper case (18) is assembled to the lower case (16), the tip portion of the ring-shaped convex portion (26'a) enters the gap (31), and the O-ring (30) is attached to the tip portion. Plane and the upper The inner peripheral surface of the over scan (18), the sealing structure of an electronic device characterized by sandwiching in three surfaces of the lower circular clamping portion of the peripheral surface of the connector portion (20).