JPH09120734A - Push-button switch - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a push-button switch which can be manufactured simply at a low cost and can be surface mounted simply on a printed circuit board using an electroconductive adhesive. SOLUTION: A switch wafer 3 made of an insulative resin and electroconductive resin members 4, 5 are formed in a single piece, and an electric path from a pair of stationary contacts 4a, 5a exposed at the oversurface of the safer 3 to terminal parts 4b, 5b exposed at the bottom surface of the wafer 3 is secured by these resin members 4, 5. An operating member 7 is installed in the wafer 3, and a movable contact 6 capable of contacting with and separating from the stationary contacts 4a, 5a is furnished on this operating member 7. The terminal parts 4b, 5b are connected with the land of a printed circuit board 2 by the use of an electroconductive adhesive 16, and the output signals from the stationary contacts 4a, 5a are sent to the circuit board 2 via the terminal parts 4b, 5b.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a push button switch, and more particularly to a push button switch suitable for surface mounting on a printed circuit board.

[0002]

2. Description of the Related Art A general push button switch known in the prior art includes a switch wafer made of an insulating resin, a pair of fixed contacts outsert-molded on the switch wafer, and a movable wafer built in the switch wafer. A contact and an operating body for bringing the movable contact into and out of contact with the fixed contact are provided. The fixed contact passes through the inside of the switch wafer and then protrudes to the outside of the switch wafer to form a terminal portion. ing. These fixed contacts and terminals are made of a conductive metal plate, and in the case of a surface mount type push button switch, they are bent along the side surface of the switch wafer.

In the push button switch having the above-mentioned general structure, the cream solder is applied to the land portion of the printed circuit board, the terminal portion is placed on the cream solder, and then the cream solder is melted by the reflow furnace. Due to
It is designed to be surface-mounted on a printed circuit board.

[0004]

By the way, in the above-mentioned conventional push button switch, since the push button switch has the terminal portion projecting along the side surface of the switch wafer, the conductive metal plate is outserted on the switch wafer. After molding, it is necessary to fold the terminal portion, which causes a problem of high manufacturing cost. In addition, because the fixed contact is formed by outsert molding a conductive metal plate on the switch wafer, the insulating resin of the switch wafer wraps around the surface of the fixed contact during outsert molding, and the movable contact does not contact the fixed contact. There was a concern that a defect would occur. Further, there is a problem in that the soldering work becomes complicated because the step of applying the cream solder and the step of melting the cream solder by the reflow furnace are required to connect the terminal portion to the land portion of the printed circuit board.

The present invention has been made in view of the above-mentioned circumstances in the prior art, and an object thereof is to easily surface-mount a printed circuit board using a conductive adhesive, and to make the manufacturing simple and inexpensive. To provide a simple push button switch.

[0006]

In order to achieve the above object, the present invention provides a switch wafer made of an insulating resin,
The switch wafer is provided with a fixed contact and a terminal portion thereof, a movable contact corresponding to the fixed contact, and an operating body for bringing the movable contact into and out of contact with the fixed contact. The most main feature is that resin is integrally molded, and a conductive path between the fixed contact and the terminal portion is formed by this conductive resin. Furthermore, the terminal portion is provided only on the bottom surface of the switch wafer. I made it exposed.

According to the present invention, the fixed contact and its terminal portion are formed of a conductive resin, and this conductive resin is integrally molded with the switch wafer made of an insulating resin. Therefore, the terminal portion exposed from the switch wafer is made conductive. Since it can be connected to the land portion of the printed circuit board by using an adhesive, it can be easily surface-mounted on the printed circuit board without complicated soldering. Also, since the switch wafer and the conductive resin are molded between the resins,
It is possible to prevent the surface of the fixed contact from being covered with resin,
The bending process of the terminal portion can be omitted.

[0008]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 is a sectional view of a push button switch according to an embodiment of the present invention, FIG. 2 is a plan view showing a state in which an operating body is removed from the push button switch, and FIG. 3 is a bottom view of the push button switch. It is a figure.

The push button switch 1 shown in FIG. 1 comprises a switch wafer 3 made of an insulating resin, conductive resin bodies 4 and 5 integrally formed on the switch wafer 3, and an operating body mounted on the switch wafer 3. 7 and a holding plate 13 for attaching the operating body 7 to the switch wafer 3. The upper ends of the conductive resin bodies 4 and 5 are exposed from the center of the upper surface of the switch wafer 3 to form fixed contacts 4a and 5a, and the lower ends of the conductive resin bodies 4 and 5 are exposed from the bottom surface of the switch wafer 3 to form terminals. The parts 4b and 5b are formed.

The operating body 7 is made of an elastic material such as silicon rubber, and has a bowl portion 9 and a pressing portion 8 projecting upward from the center of the bowl portion 9, and an inner bottom surface of the bowl portion 9 is provided. Is provided with a movable contact 6 which faces the fixed contacts 4a and 5a with a predetermined space therebetween. The bowl portion 9 buckles with a click feeling when the pushing portion 8 is pushed, and the buckling of the bowl portion 9 causes the movable contact 6 to come into contact with and separate from the fixed contacts 4a, 5a. There is.

An inner bottom portion 10 having a circular shape in plan view and an outer peripheral wall 11 surrounding the inner bottom portion 10 are formed on an upper portion of the switch wafer 3, and an annular protrusion 12 is projected upward from the inner bottom portion 10. There is. The outer peripheral edge of the lower end of the bowl portion 9 is fitted between the protrusion 12 and the outer peripheral wall 11, and the bowl portion 9
The operation body 7 is prevented from falling off the switch wafer 3 by pressing the upper part of the peripheral edge thereof with the pressing plate 13. The pressing plate 13 is inserted into the pins 14 formed at the four corners of the outer peripheral wall 12 and then the pins 14 are inserted.
The upper end of the outer peripheral wall 12 is fixed to the upper end of the outer peripheral wall 12 by deforming the upper end of the outer peripheral wall to form the caulked portion 15.

The conductive resin bodies 4 and 5 are integrally molded with the switch wafer 3 by a technique called a two-color molding method. The conductive resin body 4 is formed into an L shape as shown in FIG. 1 and forms a conductive path between the fixed contact 4a and the terminal portion 4b inside the switch wafer 3.
The other conductive resin bodies 5 are also the same, and form a conductive path between the fixed contact 5a and the terminal portion 5b inside the switch wafer 3.

As shown in FIG. 1, the push button switch 1 constructed as described above is mounted on the printed circuit board 2 and the terminal portions 4b and 5b exposed from the bottom surface of the switch wafer 3 are sandwiched by a conductive adhesive 16. The printed circuit board 2 is mounted on the printed circuit board 2 by being connected to a land portion (not shown) of the printed circuit board 2. When the operator presses the pressing portion 8 of the operating body 7, the bowl portion 9 buckles with a click feeling, and the movable contact 6 comes into contact with the fixed contacts 4a and 5a to be switched on. When the pressing force applied to the pressing portion 8 is removed, the bowl portion 9 returns to the posture shown in FIG. 1 due to its elasticity, and the movable contact 6 separates from the fixed contacts 4a and 5a and is switched off.

In the push button switch 1 thus constructed, the conductive resin bodies 4, 5 are integrally molded with the switch wafer 3 made of an insulating resin, and the fixed contacts 4a, Since the conductive paths between the terminals 5a and the terminals 4b and 5b are formed, the terminals 4b and 5b exposed from the switch wafer 3 can be connected to the lands of the printed circuit board 2 by using the conductive adhesive 16, and the complicated soldering is required. The printed circuit board 2 can be easily surface-mounted without requiring attachment. Also,
Since the switch wafer 3 and the conductive resin bodies 4 and 5 including the fixed contacts 4a and 5a are integrated by two-color resin molding, the surface of the fixed contacts 4a and 5a is covered with the insulating resin of the switch wafer 3. It becomes difficult, and the movable contact 6 can be reliably brought into contact with the fixed contacts 4a and 5a, and
Bending of the terminal portions 4b and 5b can be omitted. Furthermore, the terminal portions 4b and 5b can be exposed from any surface of the switch wafer 3, and particularly when the terminal portions 4b and 5b are exposed only from the bottom surface of the switch wafer 3 as in the above embodiment, the switch wafer 3 can be exposed. Since the live part is not exposed on the side surface of 3, it is possible to reliably prevent a short circuit accident in which other circuit parts or the like come into contact with the terminal parts 4b and 5b.

FIG. 4 is a sectional view of a push-button switch according to another embodiment of the present invention. In the figure, the same parts as those shown in FIGS.

The push-button switch 17 shown in FIG. 4 differs from the push-button switch 1 described above in that the tact spring 18 in which the movable contacts contacting and separating from the fixed contacts 4a and 5a are formed in a dome shape.
The operating body for bringing the tact spring 18 into contact with and separating from the fixed contacts 4a, 5a consists of the stem 19 for pressing the tact spring 18, and the other configurations are basically the same. With the push button switch 17 configured as above, the same effect as that of the push button switch 1 described above can be obtained.

[0018]

As described above, according to the present invention,
Since the fixed contacts and their terminals are made of conductive resin and this conductive resin is integrally molded with the switch wafer made of insulating resin, the terminals exposed from the switch wafer are printed on the printed circuit board land using a conductive adhesive. Can be connected to the board, and can be easily surface-mounted on the printed circuit board without the need for complicated soldering. In addition, since the switch wafer and the conductive resin are resin-molded with each other, the surface of the fixed contact is not covered with the insulating resin, the reliability of the contact of the movable contact with the fixed contact can be improved, and the terminal portion can be improved. The manufacturing cost can be reduced by omitting the bending process.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view of a push button switch according to an embodiment of the present invention.

FIG. 2 is a plan view showing a state in which an operating body is removed from the push button switch.

FIG. 3 is a view of the push button switch as seen from the lower surface side.

FIG. 4 is a cross-sectional view of a push button switch according to another embodiment of the present invention.

[Explanation of symbols]

 1 Push Button Switch 2 Printed Circuit Board 3 Switch Wafer 4,5 Conductive Resin Body 4a, 5a Fixed Contact 4b, 5b Terminal Part 6 Moving Contact 7 Operating Body 8 Pressing Part 9 Circle Bowl Part 16 Conductive Adhesive 17 Push Button Switch 18 Tact Spring (Movable contact) 19 Stem (Operator)

Claims (2)

[Claims] 1. A switch wafer made of an insulating resin,
The switch wafer is provided with a fixed contact and a terminal portion thereof, a movable contact corresponding to the fixed contact, and an operating body for bringing the movable contact into and out of contact with the fixed contact. A pushbutton switch, characterized in that resin is integrally molded, and a conductive path between the fixed contact and the terminal portion is formed by the conductive resin. 2. The pushbutton switch according to claim 1, wherein the terminal portion is exposed only on the bottom surface of the switch wafer.