JP2905984B2 - Push button switch and molding method thereof - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a push button switch having a conductive portion on the upper inside of a hollow mesa-shaped (reverse bowl-shaped) elastic body.

"Prior art" The above-mentioned push-button switch has a known example such as JP-A-64-3930 and JP-A-63-18727, and as shown in FIG. 6, an insulating member made of an elastic material such as silicone rubber is used. Conductive portion 2 made of a conductive material on the upper portion inside the elastic hollow mesa-shaped elastic body 1
Have a shape integrally formed downward, and the elastic body 1
The contact 12 and the conductive part 2 on the substrate 15 are
Are brought into contact with each other.

[Problem to be Solved by the Invention] The above-described push button switch has a structure in which the conductive portion 2 is integrally protruded inside the hollow mesa-shaped elastic body 1. As shown in the drawing, the injection gate 11 has to be set on the lower surface of the conductive portion 2, and thus the lower surface of the formed conductive portion 2, that is, the flat contact surface 5 of the conductive portion 2 is formed.
In addition, the remaining protrusions 4 based on the injection gate 11 are generated, the remaining protrusions 4 become harmful substances, and the poor contact between the conductive portion 2 and the contact 12 is likely to occur. Therefore, it is necessary to remove the remaining protrusions 4 to prevent it. As a result, there is a problem that the unnecessary removal process increases and the cost increases.

Further, since the above-mentioned conventional structure has a structure in which the elastic body 1 made of an insulating material and the conductive part 2 made of a conductive material mixed with carbon or the like are integrally bonded or integrated by injection molding, In order to prevent the two from separating when the switch is used, a weight must be used for the adhesion between the two, so the combination of the elastic body 1 and the conductive part 2 is limited to a narrow range, and the degree of freedom in material selection is hindered. There are drawbacks.

The present invention provides a push button switch that solves the above-mentioned drawbacks of the conventional means, and a method of forming the same.

"Means for Solving the Problems" The present invention for solving the above technical problems is a push button switch in which a conductive portion having a flat contact surface facing downward is integrally provided on the upper inside of a hollow mesa-shaped elastic body. A push button switch having a gist of a structure in which a columnar conductive portion is inserted and locked by locking means including a lower end enlarged diameter portion, an intermediate reduced diameter portion, and an upper end enlarged diameter portion in the upper and lower through holes of the elastic body, "When forming a pushbutton switch having a columnar conductive part in the center upper and lower through-holes of the hollow mesa shape, it is joined by a part line, and a mating die is formed to unite the molding cavity of the pushbutton switch at the joint part. A first position having an outer edge of a body cavity, an inner edge of a through hole, and an ejection gate for an elastic body, and a second position having an outer edge of a push button switch cavity and an ejection gate for a columnar conductive portion? A movable mold having an inner edge of an elastic body cavity, a lower end enlarged diameter cavity, and a molding pin that makes the lower end enlarged diameter cavity solid or hollow by moving back and forth. Is joined to the first position of the fixed mold, and the elastic body is injection-molded by advancement of the molding pin with the lower end enlarged diameter cavity solid, and then the movable mold is moved to the second position of the fixed mold. To form the hollow at the lower end enlarged diameter portion by retracting the molding pin,
A method of forming a column-shaped conductive portion integrally with an elastic body formed by the first position.

[Operation] Since the push button switch of the present invention has a structure in which a column-shaped conductor penetrating vertically is provided at the center of a hollow mesa-shaped elastic body, an injection gate for injection-molding the conductive portion is formed by a conductive material. Since it is possible to set and mold on the upper side of the portion (outside the elastic body), the remaining protrusion based on the injection gate does not occur on the contact surface with the contact.

Further, since the through hole of the elastic body and the columnar conductive portion inserted and formed in the through hole are mechanically locked in the vertical direction by the locking means, the bonding between the elastic body and the columnar conductive portion is performed. Requirement of properties is unnecessary, and the degree of freedom of material selection based on each function is improved.

"Example" Hereinafter, a detailed description will be given based on an example. First, referring to FIG. 1 showing one embodiment of a push button switch of the present invention,
In the push button switch in which the flat contact surface 5 faces downward in the center of the hollow meter-shaped elastic body 1, through holes 13 are provided in the center of the elastic body 1 so that the columnar conductive portion 2 is inserted and locked. Have been. More specifically, the columnar conductive portion 2 has a lower swelling portion 17.
A stepped columnar body consisting of an intermediate reduced diameter portion 18 and an upper end enlarged diameter portion 19 of a straight cylinder and closely adhered to the inner periphery of the through hole 13,
The lower end enlarged diameter portion 17 engages with the lower end edge of the through hole 13 and is exposed,
The upper end enlarged diameter portion 19 is embedded in the through hole 13. And
Due to the step formed between the inner periphery of the through hole 13 and the joining surface of the columnar conductive portion 2, the two have locking means that are mechanically locked and fixed.

2 and 3 show other embodiments of the push button switch according to the present invention.
The column-shaped conductive portion 2 is inserted and locked in the through-hole 13 of the elastic body 1 with a locking means including an upper end enlarged diameter portion 19 and an upper end enlarged diameter portion. 19 engages with the upper end of the through-hole 13. FIG.
The 19 sections are truncated cylinders.

The push-button switch of each embodiment described above has the above-described operation.
That is, the columnar conductive portion 2 inserted and locked in the central through-hole 13 of the hollow meter-shaped elastic body 1 is mechanically and accurately locked to the through-hole 13 by the locking means. Mutual adhesion between the column 13 and the columnar conductive portion 2 becomes unnecessary. Therefore, there is no need to consider the adhesiveness between the two, and the elastic body 1 and the columnar conductive portion 2
Can select a material that gives priority to "elasticity, durability, and temperature assurance" that satisfies each function, and the "degree of freedom of material selection" is particularly improved. Since the bonding operation is unnecessary, the molding process of the hollow mesa type push button switch is simplified, and the molding productivity is improved.

Next, an embodiment of the molding method of the present invention will be described with reference to FIGS. As shown in FIG. 4, the molding die used in this molding method is composed of a combination of a movable die 20 and a fixed die 21 which are joined together at the part line 6 to form a molding cavity of a push button switch at the joint thereof. The fixed mold 21 includes "the first edge 22 having the outer edge 24 of the elastic body cavity 30, the inner edge 25 of the through hole, and the injection gate 11A for the elastic body" and the "outer edge 26 of the push button switch cabin 31 and the injection for the columnar conductive portion. The other movable mold 20 is composed of the inner edge 27 of the elastic cavity 30.
And a lower-end enlarged diameter portion cavity 28, and a retractable molding pin 29 that makes the lower-end enlarged diameter portion cavity 28 solid or hollow by moving forward and backward. It moves between the first position 22 and the second position 23 and is joined at each position, and the following molding process is performed.

That is, referring to FIG. 5 showing the processing procedure, first, the movable mold 20 is combined with the first position 22 of the fixed mold 21 and the forming pin 29 is advanced to make the lower end enlarged diameter cavity 28 solid. . Then, the molten material is eluted from the injection gate 1A into the elastic body cavity 30 that has been united and formed by the die joining, whereby the elastic body 1 is formed.

Then, after the elastic body 1 is cooled and solidified, the movable mold 20 moves with the molded elastic body 1 attached, and is joined to the second position 23 of the fixed mold 21, and the molding pin 29 is retracted to the lower end. The enlarged diameter portion cavity 28 is not hollow, and a columnar conductive portion cavity is generated. Then, the molten material is injected into the conductive portion cavity 31 from the injection gate 11B, the columnar conductive portion 2 is integrally formed with the already formed elastic body 1, and after cooling and solidification, the mold is opened and taken out.

When the movable mold 20 moves from the first position 22 to the second position 23, the elastic body 1 formed by the first position 22 is formed by the upper end expanded portion 19 of the columnar conductive portion 2 and the intermediate reduced diameter portion.
It is retracted from the protruding pin 32 on the fixed mold side corresponding to 18 and easily pulled out, and is moved while being attached to the movable mold 20.

In the drawing, reference numeral 33 denotes an injection runner groove, and reference numeral 34 denotes an injection nozzle.

The elastic body 1 of the push button switch of the present invention is formed of a thermoplastic elastomer or a thermosetting rubber having injection moldability, and the conductive part 2 is provided with conductivity by adding carbon powder or metal powder. Molded thermoplastic elastomer or thermosetting rubber having injection moldability.

[Effect of the Invention] As described above, the push-button switch of the present invention is a hollow maser-shaped elastic body in which a columnar conductive portion is integrally provided in a central through hole, and the adhesion between the through hole and the columnar conductive portion is provided. Since the locking becomes unnecessary, each of the two is not restricted by the adhesiveness, and the material can be selected by giving priority to the respective functions. By selecting the material, the push button switch performance is more stable, and the switch quality is improved and stabilized.

Furthermore, since harmful residual protrusions on the lower surface of the columnar conductive portion become non-existent, the push button switch performance by the columnar conductive portion is stabilized, and the conventional protrusion removal work due to the absence of the residual protrusion is omitted. By omitting the conventional bonding operation due to the non-use of bonding, a series of processing for forming the push button switch is simplified, the processing productivity is improved, and the molding cost is reduced. There are the above effects.

[Brief description of the drawings]

FIG. 1 shows a push button switch according to an embodiment of the present invention, and FIG.
Fig. 2B is a front view of a push button switch according to another embodiment of the present invention, and Fig. 4 is a front view of a molding die according to an embodiment of the present invention. Figure, Figure 5: Figure 4
FIG. 6 is a front view of a conventional push button switch, and FIG. 7 is a front view showing a method of forming a conventional push button switch. Main symbols, 1: elastic body, 2: conductive Part, 4: residual protrusion, 5: flat contact surface, 6: part line, 11: injection gate, 12: contact, 13:
Through-hole, 17: bottom bulge, 18: middle bulge, 19: top bulge, 20: mobile, 21: fixed, 22: first position, 23: second position, 28: bottom bulge Diameter cavity, 29: molding pin, 30: elastic cavity, 31: push button cavity

Claims (2)

(57) [Claims] 1. A push-button switch in which a conductive portion having a flat contact surface facing downward is integrally provided on an upper portion inside a hollow mesa-shaped elastic member. A push button switch having a structure in which a columnar conductive portion is inserted and locked by locking means including a reduced diameter portion and an upper end enlarged diameter portion. 2. A method of forming a push button switch having a columnar conductive portion in the center upper and lower through-holes of a hollow mesa-shaped elastic body by joining at a part line and forming a molding cavity of the push button switch at the joined portion. From the first position having the outer edge of the elastic body cavity and the inner edge of the through hole, and the injection gate for the elastic body, and the second position having the outer edge of the push button switch cavity and the injection gate for the columnar conductive portion. A movable mold having an inner edge of an elastic body cavity, a lower end enlarged diameter cavity, and a molding pin that makes the lower end enlarged diameter cavity solid or hollow by moving back and forth. Is joined to the first position of the fixed mold, and the elastic body is injection-molded by advancing the molding pin to solidify the cavity at the lower end expanded portion. Thereafter, the movable mold is joined to the second position of the fixed mold, the molding pin is retracted to make the lower end expanded diameter cavity hollow, and the elastic body molded by the first position is formed into a columnar shape. A method for forming a push button switch, wherein a conductive portion is integrally formed.