JPH0963391A - Installing structure of electric part - Google Patents

Abstract

PROBLEM TO BE SOLVED: To reliably prevent mixing of air in resin from the electric part side and the inflow of resin into the electric part side when a printed circuit is covered with resin by covering the whole electric part installed on the printed circuit board or the like with a sealing member, and pressing down a peripheral part of the sealing member by a pressing-down metal fitting. SOLUTION: An electric part 1 installed on a printed circuit board 20 is covered with a sealing member 5 having an annular groove 9, and a peripheral part 7 and the annular groove 9 of the sealing member 5 are pressed against a surface of the printed circuit board 20 by a pressing-down metal fitting 10 having a projecting part 15. The pressing-down metal fitting 10 presses the peripheral part 7 of the sealing member 5 against the printed circuit board 20, and the projecting part 15 of the pressing-down metal fitting 10 bites into the annular groove 9 of the sealing member 5, and a sealing degree of a very high degree is realized. Therefore, when the printed circuit board 20 is covered with resin or the like, mixing of air in the resin from the electric part 1 side is not caused, and that the resin flows in the electric part 1 side and infiltrates into the electric part 1, can be reliably prevented.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a mounting structure for an electric component that is mounted by covering a microswitch or the like with a seal rubber or the like.

[0002]

2. Description of the Related Art Micro switches are widely used in various electric equipments, but when they are used, it is necessary to take measures against water and dust to cope with the environment.

As such a waterproof and dustproof measure, for example, a micro switch mounted on a circuit board is covered with a rubber seal member, and further, the periphery of the seal member, the circuit board, and the micro on the back surface of the circuit board are covered. The soldered parts of the switch connection terminals are integrally covered with a resin material such as urethane, and thus, the upper surface of the microswitch,
It completely blocks the entry of water and dust from the bottom surface.

[0004]

However, in the case of the structure in which the contact portion between the peripheral portion of the seal member and the mounting surface is covered with the resin material as described above, the following problems occur.

That is, for example, a contact portion is covered by heating and curing a resin material such as urethane resin. At this time, the contact between the peripheral portion of the seal member and the mounting surface is in a sealed state. If not removed, the air from the bottom side of the microswitch will enter the urethane resin through the contact portion. As a result, the urethane resin is foamed and the strength of the urethane resin portion is reduced.

On the contrary, when the urethane resin enters the bottom surface of the micro switch from the contact portion, it further enters the inside of the switch through the gap portion of the micro switch, which causes malfunction of the contacts.

The present invention is made to solve the above problems, and it is an object of the present invention to reliably prevent foaming of the above resin material and intrusion of urethane resin into the microswitch.

[0008]

In order to achieve the above object, in the invention according to claim 1 of the present invention, an electric component is mounted on a mounting surface, and the entire electric component is covered with a seal member, and , In a mounting structure of an electric component in which a peripheral edge of the sealing member is brought into contact with a mounting surface at a peripheral position of the electric component, a pressing metal fitting for pressing the peripheral edge to the mounting surface is mounted on the peripheral edge of the sealing member. It has been configured as follows.

According to a second aspect of the present invention, in the first aspect of the present invention, the pressing fitting further includes a protrusion that presses the peripheral edge of the seal member.

According to a third aspect of the present invention, in addition to the first aspect of the invention, an annular continuous protrusion is further formed on the lower surface of the peripheral edge of the seal member.

[0011]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1 is an assembly exploded perspective view showing a mounting structure of an electric component of the present invention. First, each member will be described with reference to this drawing.

Reference numeral 1 denotes a micro switch as an electric component, in which an operation switch 3 is provided on the upper surface of a casing 2 and three connecting terminals 4 project from the lower surface.

Reference numeral 5 denotes a seal rubber as a seal member, which is made of a rubber material such as CR, EPDM or silicon rubber. The seal rubber 5 has a shape along the outer shape of the micro switch 1, and a pressing operation portion 6 is formed on the upper surface at a position facing the operation switch 3 of the micro switch 1. Further, a peripheral edge portion 7 is provided on the entire lower circumference of the seal rubber 5 so as to project laterally, and a projection portion 8 continuous in an annular shape is integrally formed on the lower surface thereof as shown in FIG. Further, an annular groove 9 is formed on the upper side of the base of the peripheral edge portion 7.
Are formed.

Reference numeral 10 is a holding metal fitting, which has a rectangular opening 1
1 is provided with an annular portion 13 composed of four sides, and the annular portion 1
As shown in FIG. 3, an annularly continuous protrusion 15 is formed so as to protrude downward from the inner peripheral edge of 3. A bifurcated locking projection 17 is formed so as to project downward from the center position of each side of the outer circumference of the annular portion 13.

Reference numeral 20 denotes a printed circuit board which constitutes a mounting surface, and is provided with three terminal insertion holes 21 into which the connection terminals 4 of the microswitch 1 are respectively inserted, and a locking projection of the pressing metal fitting 10. Four locking holes 23 for locking each of 17 are formed.

The mounting structure will be described below. FIG. 4 is a perspective view showing the mounting structure of the microswitch 1,
FIG. 5 is a sectional view.

The connection terminals 4 of the microswitch 1 are inserted into the respective terminal insertion holes 21 of the printed circuit board 20, and the ends of the connection terminals 4 are soldered to the connection patterns on the back surface of the printed circuit board 20. A seal rubber 5 is attached so as to cover the micro switch 1, the annular portion 13 is placed on the peripheral edge portion 7, and the locking protrusions 17 are locked in the locking holes 23, respectively. Therefore, the metal fitting 10 is attached. Since the locking projections 17 are formed in a bifurcated shape, when the locking projections 17 are inserted into the locking holes 23, the inclined portions 28 on both sides are pushed by the edges of the locking holes 23 so that the width of the locking projections 17 is narrowed. In the completed state, the locking portion 29 is elastically opened to lock with the lower surface of the printed circuit board 20.

In the state where the pressing metal fitting 10 is attached as described above, the annular portion 13 of the pressing metal fitting 10 is attached to the seal rubber 5.
The peripheral edge portion 7 of the is elastically pressed against the printed circuit board 20 surface,
As a result, the lower surface of the peripheral edge portion 7 and the surface of the printed circuit board 20 are sealed. In particular, at that time, the annular protrusion 15 of the holding metal fitting 10 bites into the annular groove 9 of the seal rubber 5 on the one hand, and the annular protrusion 8 on the lower surface of the peripheral edge 7 is compressed to the crushed state on the other hand. , A very high degree of sealing is achieved.

Therefore, when the urethane resin 40 is coated, the air from the microswitch 1 side does not enter the urethane resin 40, and the urethane resin 4
It is reliably prevented that 0 flows into the micro switch 1 side and enters the inside of the switch.

[0020]

According to the present invention, the pressing metal member presses the peripheral edge of the seal member against the mounting surface, thereby sealing between the lower surface of the peripheral edge and the mounting surface.
When the urethane resin is coated, air from the electric component side does not enter the resin, and the resin is surely prevented from flowing into the electric component side and entering the electric component. It

As a result, a stable coating structure of resin can be obtained, and malfunctions of electric parts can be eliminated.

In particular, if the pressing metal fitting is provided with an annular projection for pressing the peripheral edge of the seal member, or if an annular projection is provided on the lower surface of the seal member for pressure contact with the mounting surface,
Further high sealing property is obtained, and the above effect becomes more effective.

[Brief description of drawings]

FIG. 1 is an exploded perspective view showing a mounting structure of a micro switch.

FIG. 2 is a sectional view of a seal rubber.

FIG. 3 is a cutaway sectional view of a holding metal fitting.

FIG. 4 is a perspective view showing a mounting structure of a micro switch.

FIG. 5 is a sectional view showing a mounting structure of a micro switch.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Micro switch (electrical component) 5 Seal rubber (seal member) 7 Peripheral part 8 Projection part 10 Holding metal fittings 15 Projection part 20 Printed circuit board (mounting surface)

Claims (3)

[Claims] 1. An electric component is mounted on a mounting surface, and the entire electric component is covered with a seal member.
And, in the mounting structure of the electrical component in which the peripheral portion of the sealing member is brought into contact with the mounting surface at the peripheral position of the electrical component, in the peripheral portion of the sealing member, a pressing metal fitting for pressing the peripheral portion to the mounting surface is provided. A mounting structure for electric parts, which is characterized by being mounted. 2. The pressing member includes a protrusion that presses a peripheral portion of the seal member.
Attachment structure for the described electrical components. 3. The mounting structure for an electric component according to claim 1, wherein a protrusion continuous in an annular shape is formed on a lower surface of a peripheral portion of the seal member.