JP6376400B2 - Pushbutton switch and manufacturing method thereof - Google Patents

Description

  The present invention relates to a pushbutton switch and a manufacturing method thereof.

A push button switch is used as a data input device for electronic equipment.
In such a push button switch, as shown in FIG. 8, a pusher portion 1, a key top portion 2, and a dome portion 4 for supporting the key top portion 2 on a base portion 3 are integrally formed of an elastic material such as rubber. The dome portion 4 is formed in a thin dome shape so as to be elastically deformed by a pressing load applied to the key top portion 2.

FIG. 9 is a graph showing the pressure load and stroke (displacement) characteristics of such a pushbutton switch (hereinafter also referred to as a press characteristic).
When the user pushes in the key top portion 2, the load increases with the stroke due to the elastic deformation of the dome portion 4 (arrow 1 in FIG. 9).
When the load reaches the peak load (F _P ), the dome portion 4 buckles and the load decreases (arrow 2 in FIG. 9).
The user can feel a click feeling (operation feeling) of the push button switch due to this sudden load drop.

When the stroke becomes the on-stroke (S _O ), the tip of the pusher portion 1 reaches the substrate, and the conductive portion 5 provided at the tip of the pusher portion 1 contacts the fixed electrode 6 of the substrate to transmit an electrical signal.
When the user pushes in the key top part 2 even after the on-stroke, the load increases again due to bending of the pusher part 1 and the key top part 2 reaching the substrate (arrow 3 in FIG. 9). Full stroke ( _SF ) To reach.

When the user opens the key top portion 2, the bent pusher portion 1 and the key top portion 2 are turned on-stroke by the restoring force of rubber (arrow 4 in FIG. 9).
The load at this time is the return load (F _R ).
Thereafter, the buckled dome part 4 returns to the original state, and the elastically deformed dome part 4 returns to the initial state (arrows 5 and 6 in FIG. 9).
For example, such pushbutton switches are disclosed in Patent Documents 1 and 2.

JP-A-11-306908 Japanese Patent No. 4975637

By the way, in recent years, a higher click feeling (operation feeling) has been demanded, and for this reason, it is necessary to select a rubber material having a high rubber hardness as a rubber material used for a push button switch.
However, when a push button switch is made of a high hardness rubber material having a high rubber hardness, a high click feeling can be obtained, but a load increase after an on-stroke becomes abrupt, which gives the operator a mechanical feel. There's a problem.

  The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a pushbutton switch that can achieve both a high click feeling and a soft feel, and a method of manufacturing the pushbutton switch. .

The present invention is grasped by the following composition in order to achieve the above-mentioned object.
(1) The pushbutton switch of the present invention includes a key top in which a dome portion, a base portion connected by the dome portion and a key top portion are integrally formed of a first material, and a direction from the key top portion to the base portion And a pusher portion formed of a second material provided so as to protrude from the first material, wherein the second material is made of a softer material than the first material.
(2) In the configuration of (1) above, the hardness value of a type A durometer measured by the measurement method according to JIS K 6253-3: 2012 of the first material is X, and JIS K of the second material If the hardness value of the type A durometer measured by the measuring method according to 6253-3: 2012 is Y, the second material has a hardness X of the first material to a hardness Y of the second material. It is a soft material with a value W minus 5 being 5 or more.
(3) In the configuration of (1) or (2), the pusher portion protrudes 0.45 mm or more from the key top portion toward the base portion.

(4) In any one of the constitutions (1) to (3), the key top portion and the pusher portion are fused and integrated with each other.
(5) In the configuration of (4), the first material and the second material are silicone rubber.

(6) In any one of the constitutions (1) to (3), the key top portion and the pusher portion are bonded and integrated with an adhesive material.
(7) In the configuration of (6) above, a convex portion or a concave portion is formed on the key top portion side in a portion integrated with the adhesive material of the key top portion and the pusher portion, and on the pusher portion side. A concave portion or a convex portion that fits into the convex portion or the concave portion of the key top portion is formed.

(8) In any one configuration of the above (1) to (7), the pusher portion has an amount of entering the key top portion side of 50% or less of the height of the key top portion.

(9) In any one of the configurations (1) to (8), a conductive portion is provided on at least one end face of the pusher portion located on the opposite side to the key top portion.
(10) In the configuration of (9), the conductive portion has an outer shape equal to or smaller than an outer shape of the end surface of the pusher portion provided with the conductive portion.

(11) The manufacturing method of the pushbutton switch of the present invention includes a pusher part molding step for molding a pusher part with a second material made of a softer material than the first material, and a base connected with the dome part and the dome part. An integration step of integrating the pusher portion with the key top portion of the key top integrally molded with the first material so that the portion and the key top portion protrude from the key top portion toward the base portion; ,including.

(12) In the configuration of the above (11), the hardness value of a type A durometer measured by the measurement method according to JIS K 6253-3: 2012 of the first material is X, and JIS K of the second material If the hardness value of the type A durometer measured by the measuring method according to 6253-3: 2012 is Y, the second material has a hardness X of the first material to a hardness Y of the second material. It is a soft material with a value W minus 5 being 5 or more.

(13) In the configuration of (11) or (12) above, in the integration step, the pusher portion is integrated with the key top portion so that the pusher portion protrudes 0.45 mm or more from the key top portion toward the base portion. Is done.

(14) In any one of the constitutions (11) to (13), the first material and the second material are base materials having the same resin material and different hardness, In the integration step, the first material is heated in a state of being pressurized in the inner space of the mold, and when the key top is molded, the integration step is formed on the mold that opens to the inner space. In this step, the pusher portion disposed in the bottom recess is fused and integrated with the key top portion.

  According to the present invention, it is possible to provide a pushbutton switch that can achieve both a high click feeling and a soft feel, and a method for manufacturing the pushbutton switch.

It is a figure which shows the pushbutton switch of 1st Embodiment which concerns on this invention. It is a figure explaining the manufacturing method of the keytop of 1st Embodiment. It is a figure explaining the manufacturing method in case a pusher part enters into the keytop part of 1st Embodiment. It is a figure explaining the pushbutton switch when a pusher part enters into the key top part of 1st Embodiment. It is a graph which shows the characteristic of the pushbutton switch of 1st Embodiment. It is a figure which shows the pushbutton switch of 2nd Embodiment which concerns on this invention, (a) is a case where a pusher part is adhere | attached and integrated with a key top part, (b) A recessed part is provided in a key top part, and it protrudes in a pusher part. (C) is a case where a convex structure is added to the key top part and a concave part is provided to the pusher part to add a fitting structure in addition to adhesion. d) is a case where a flange is provided in the pusher portion to increase the bonding area. It is a modification of 1st and 2nd embodiment which does not provide an electroconductive part in the pusher part which concerns on this invention. It is a figure which shows the conventional pushbutton switch. It is a graph explaining the relationship between the stroke of a pushbutton switch, and a load.

DESCRIPTION OF EMBODIMENTS Hereinafter, embodiments for carrying out the present invention (hereinafter referred to as “embodiments”) will be described in detail with reference to the accompanying drawings.
Note that the same number is assigned to the same element throughout the description of the embodiment.

(First embodiment)
FIG. 1 is a diagram showing a cross-sectional structure of a pushbutton switch according to a first embodiment of the present invention.
As shown in FIG. 1, the pushbutton switch 10 of the first embodiment includes a key top 20, a pusher part 30, and a conductive part 40.

In the key top 20, a base portion 21 and a key top portion 23 connected by the dome portion 22 and the dome portion 22 are integrally formed of a first material.
Examples of the first material include, for example, urethane rubber, acrylic rubber, butyl rubber, silicone rubber, isoprene rubber, ethylene-propylene-diene terpolymer, synthetic rubber, natural rubber, polyester-based or urethane-based thermoplastic elastomer. Rubber elastic bodies such as these can be used, but among these, silicone rubber is preferred.

The pusher portion 30 is formed of a second material softer than the first material, and is provided so as to protrude from the key top portion 23 toward the base portion 21 (the lower side in FIG. 1).
Although the manufacturing method will be described later, in the present embodiment, the end surface 31 on the other side of the pusher portion 30 on the key top portion 23 side is fused and integrated at a contact portion 23 a that contacts the key top portion 23.

  By using a soft material for the pusher portion 30 in this way, a hard material is adopted for the key top 20 to obtain a click feeling, and when the pusher portion 30 is pressed toward the substrate 50 side, it is softly elastically deformed. Therefore, the pressing feeling of the push button switch 10 can be made soft, and the operator can be prevented from giving a mechanical feel when the push button switch 10 is pressed.

As the second material, similar to the first material, for example, urethane rubber, acrylic rubber, butyl rubber, silicone rubber, isoprene rubber, ethylene-propylene-diene terpolymer, synthetic rubber, natural rubber, polyester, etc. A rubber elastic body such as a thermoplastic elastomer of urethane type or urethane type can be used, among which silicone rubber is preferable.
Although the second material will be described later in the present embodiment, it is preferable that the base resin is the same resin-based material as the first material, provided that the second material needs to be softer than the first resin. is there.

  Specifically, the hardness value of the type A durometer measured by the measurement method according to JIS K 6253-3: 2012 for the first material is X, and the measurement method according to JIS K 6253-3: 2012 for the second material. When the hardness value of the type A durometer measured in step S is Y, the second material has a value W obtained by subtracting the hardness Y of the second material from the hardness X of the first material (W = X−Y). ) Is preferably a soft material with 5 or more, and more preferably, the second material is a soft material with W of 10 or more.

  The conductive portion 40 is provided on the end surface 32 on one side of the pusher portion 30 located on the opposite side of the key top portion 23. When the conductive portion 40 is pressed against the substrate 50 side, the fixed electrode 51 is conducted to transmit an electric signal. To.

  For example, a thin metal (hereinafter referred to as a metal foil) obtained by thinning nickel, copper, iron, brass, white, stainless steel or the like by roll stretching or the like is preferably used for the conductive portion 40, and the surface of these metal foils is suitably used. It is preferable to form a plating layer containing at least one of nickel, gold, and palladium by a wet plating method or a dry plating method (PVD, CVD).

  Further, the conductive portion 40 is formed with particles containing at least one of carbon, nickel, copper, silver, and gold and one or more plating layers containing at least one of nickel, gold, palladium, and silver on the surfaces of these particles. A conductive rubber containing any one or more of the particles as a filler can also be suitably used.

  Further, the conductive portion 40 is plated with at least one of nickel, gold, palladium, and silver on the surface of an insulating resin such as an acrylic resin, polycarbonate resin, urethane resin, polyester resin, or polystyrene resin. What formed one or more layers can also be used conveniently.

Next, the manufacturing method of the pushbutton switch 10 of 1st Embodiment comprised as mentioned above is demonstrated.
First, a pusher part forming step for forming the pusher part is performed.
Specifically, a sheet made of the second material to be the pusher part 30 and a conductive sheet to be the conductive part 40 are prepared.
As described above, a sheet made of a softer material than the first material is selected as the sheet made of the second material.
For example, as the conductive sheet, a metal sheet in which Ni and gold are sequentially laminated on one surface may be used.

  Then, after applying a primer on the other surface of the metal sheet and heat-drying with a dryer, the sheet is overlapped with the sheet made of the second material and placed in a mold, and compressed and integrated in a heated state. .

  Thus, after integrating the sheet | seat which consists of a 2nd material, and a metal sheet | seat, it punches out so that it may become the predetermined shape of the pusher part 30 using a press processing machine etc., and a pusher part is shape | molded.

  Next, an integration step of integrating the pusher portion 30 formed in the pusher portion forming step with the key top portion 23 so as to protrude from the key top portion 23 toward the base portion 21 is performed.

  In the manufacturing method of the present embodiment, the integration step is performed when the key top 20 is manufactured by integrally forming the base portion 21 and the key top portion 23 connected by the dome portion 22 and the dome portion 22.

The specific contents of the integration step will be described with reference to FIG.
FIG. 2 is a view showing a mold for molding the key top 20 using the first material. The mold includes a lower mold A and an upper mold B as shown in FIG. .

As shown in FIG. 2, the mold forms an internal space that becomes the shape of the key top 20 when the lower mold A and the upper mold B are combined. A bottomed recess A1 is provided in the internal space.
As shown in FIG. 2, prior to forming the key top 20, the pusher portion 30 that has been produced is disposed in the bottomed recess A <b> 1 of the lower mold A.

  At this time, the pusher is arranged so that the conductive part 40 of the end surface 32 on one side of the pusher part 30 is positioned on the side opposite to the key top part 23, that is, the conductive part 40 is disposed on the bottom side of the bottomed recess A1. The portion 30 is disposed in the bottomed recess A1.

In the present embodiment, since the conductive portion 40 is molded together when the pusher portion 30 is punched, the conductive portion 40 has substantially the same outer shape as the end surface 32 on one side of the pusher portion 30.
However, the conductive portion 40 may be affixed separately to the stamped pusher portion 30. In this case, the outer shape of the conductive portion 40 is equal to or smaller than the outer shape of the end surface 32 on one side of the pusher portion 30. It is preferable that

  When the outer shape of the conductive portion 40 is made larger than the outer shape of the end surface 32 on one side of the pusher portion 30, the size of the bottomed recess A1 is made conductive so that the conductive portion 40 can be disposed in the bottomed recess A1 shown in FIG. In this case, a gap is formed between the pusher portion 30 and the bottomed recess A1, and the material of the key top 20 may enter the gap.

  On the other hand, if the outer shape of the conductive portion 40 is made equal to or smaller than the outer shape of the end face 32 on one side of the pusher portion 30, the size of the bottomed recess A1 can be matched to the outer shape of the pusher portion 30. It can be avoided that a large gap is formed between the bottomed recess A1 and the material of the key top 20 can be prevented from entering the gap.

  Further, it is only necessary that the outer peripheral edge of the bottom surface of the bottomed recess A1 is connected to the peripheral wall of the bottomed recess A1 at a right angle. However, in reality, there are many cases where R exists, and the conductive portion 40 has a bottomed bottom. In order to prevent the conductive portion 40 from being deformed by being pressed by the R when disposed on the bottom surface of the recess A1, the outer shape of the conductive portion 40 is more than the outer shape of the end surface 32 on one side of the pusher portion 30. It is preferable to have a slightly smaller outer shape.

Let's go back and continue explaining the manufacturing method.
As described above, when the pusher portion 30 is disposed in the bottomed recess A1 of the lower mold A, the first material is introduced into the internal space formed by the lower mold A and the upper mold B, and pressurization is performed. In this state, the key top 20 is formed by integrally molding the base portion 21 and the key top portion 23 connected by the dome portion 22 and the dome portion 22 shown in FIG.

At this time, as described above, if the second material of the pusher portion 30 and the first material of the key top 20 are made of the same resin material as the base resin, when the key top 20 is molded, The contact portion between the portion that becomes the key top portion 23 and the end surface 31 on the other side of the pusher portion 30 is fused and integrated, and the push button switch 10 shown in FIG. 1 is formed.
In addition, fusion integration is not only mixing and integrating the portion that becomes the key top portion 23 of the key top 20 and the contact portion between the other end surface 31 of the pusher portion 30 during resin molding, Includes those that are chemically bonded and integrated, even if not mixed.

  As shown in FIG. 3, the end surface 31 on the other side of the pusher portion 30 slightly protrudes from the bottomed recess A <b> 1 of the lower mold A to the inside of the internal space formed by the lower mold A and the upper mold B. 4, the other end face 31 of the pusher portion 30 can be formed so as to enter the key top portion 23, and the area to be fused and integrated is increased. The portion 30 can be integrated with the key top portion 23.

  However, if the pusher part 30 enters too much into the key top part 23, the strength of the key top part 23 itself changes, and the key top part 23 is deformed when the pushbutton switch 10 is pressed. Will have an impact.

  Therefore, as shown in FIG. 4, when the pusher portion 30 enters the key top portion 23, the amount Y of the pusher portion 30 entering the key top portion 23 is equal to the height X of the key top portion 23. Is preferably 50% or less, that is, Y ≦ X × 0.5, and more preferably 30% or less.

  Further, as described above, since the pusher portion 30 is made of a softer material than the key top 20, the end surface on the other side of the pusher portion 30 is formed in order to mold the pusher portion 30 into the key top portion 23. If 31 protrudes from the bottomed recess A1 of the lower mold A into the inner space of the mold, the part may be deformed by losing the resin pressure when the key top 20 is molded. is there.

From this point of view, it is preferable not to make the condition that the pusher portion 30 enters the key top portion 23.
Specifically, the protrusion height at which the pusher portion 30 protrudes from the bottomed recess A1 of the lower die A into the inner space of the die (see Y in FIG. 4) is 50, which is the height X of the key top portion 23. % Or less, that is, Y ≦ X × 0.5 is preferable, and further, 30% or less is preferable.

The effects of the push button switch 10 of the present embodiment configured as described above will be described.
A push button switch 10 produced by the following procedure was prepared, and the push characteristics of the push button switch 10 at that time were evaluated.

(Comparative Example 1)
Silicone rubber compound KE-971-U (manufactured by Shin-Etsu Chemical Co., Ltd.) is mixed with 100 parts by weight of cross-linking agent C-8 (manufactured by Shin-Etsu Chemical Co., Ltd.), and this is 0.55 mm thick. The unvulcanized rubber sheet for the pusher part 30 was produced.
Also, prepare a metal sheet with Ni and Au plating on the surface, apply primer No18 (manufactured by Shin-Etsu Chemical Co., Ltd.) to the back of the metal sheet, and heat-treat at 200 ° C for 1 hour in a dryer. It was.

The back side of the metal sheet (primer coated surface) and the unvulcanized rubber sheet are put together in a mold with a length of 115 mm, a width of 65 mm, and a depth of 0.5 mm, and pressurized at 165 ° C. for 5 minutes. A 0.5 mm-thick sheet having a metal sheet provided on one side of the silicone rubber sheet is prepared by punching with a punching die adjusted so as to punch through to a diameter of 3 mm. The pusher portion 30 provided with the conductive portion 40 on the end face 32 was produced.
The hardness value of the type A durometer measured by the measuring method according to JIS K 6253-3: 2012 of the pusher portion 30 is 70.
In addition, the thickness of this shape | molded pusher part 30 is 0.45 mm, and the electroconductive part 40 is 0.05 mm.

  Next, a material obtained by kneading 2.0 parts by weight of a crosslinking agent C-8 (manufactured by Shin-Etsu Chemical Co., Ltd.) with 100 parts by weight of silicone rubber compound KE-971-U (manufactured by Shin-Etsu Chemical Co., Ltd.) After placing the pusher portion 30 in the bottomed recess A1 in the mold as described above as the material (first material), the first material is put into the inner space of the mold to form the dome portion 22 and the dome portion. The key top 20 was produced by integrally forming the base portion 21 and the key top portion 23 connected to each other at 22.

  In Comparative Example 1, since the pusher portion 30 has a small thickness, the material that becomes the key top 20 enters the bottomed concave portion A1, so that when the portion formed as the pusher portion 30 and the key top 20 are molded. A final pusher portion is formed with the material portion that has entered the bottomed recess A1, and the thickness of the pusher portion (the amount of protrusion protruding from the key top portion 23) is approximately 1.45 mm.

  When the key top 20 is molded, the first material molding the key top 20 has a hardness value of 70 for a type A durometer measured by the measuring method according to JIS K 6253-3: 2012. The portion of the pusher portion formed in the same has the same hardness as that of the pusher portion 30 disposed in the bottomed recess A1.

(Examples 1-3, 5)
Examples 1 to 3 and 5 use a silicone rubber compound as the base resin of the pusher part 30 as in Comparative Example 1, but each of the type A durometers measured by the measuring method according to JIS K 6253-3: 2012, respectively. A material having a hardness value of 65 in Example 1, 60 in Example 2, 50 in Example 3, and 30 in Example 5 is used.
Specifically, first, unvulcanized rubber sheets having type A durometer hardness values of 65, 60, 50, and 30 were prepared for Examples 1, 2, 3, and 5.
Also, prepare a metal sheet with Ni and Au plating on the surface, apply primer No18 (manufactured by Shin-Etsu Chemical Co., Ltd.) to the back of the metal sheet, and heat-treat at 200 ° C for 1 hour in a dryer. And put the back of the metal sheet (primer coated surface) and the unvulcanized rubber sheet together into a 300 mm long, 60 mm wide, 1.5 mm deep mold at 165 ° C. The sheet is heated for 5 minutes in a pressurized state, and a 1.5 mm thick sheet with a metal sheet provided on one side of the silicone rubber sheet is produced with each of the above rubber sheets having different hardnesses, and the sheet is punched to a diameter of 3 mm. The pusher part 30 in which the conductive part 40 was provided on the end surface 32 on one side of the pusher part 30 was manufactured by punching with the die thus adjusted.

The other points are the same as in Comparative Example 1. That is, the hardness value of the type A durometer measured by the measuring method according to JIS K 6253-3: 2012 of the key top 20 is 70.
In Examples 1 to 3, the height of the pusher portion 30 that just fits in the bottomed recess A1 when the pusher portion 30 is molded, and the pusher portion 30 made of a soft material approximately 1.45 mm from the key top portion 23 is provided. The push button switch 10 shown in FIG. The conductive portion 40 is 0.05 mm.

Example 4
Example 4 kneads 2.0 parts by weight of a crosslinking agent C-8 (manufactured by Shin-Etsu Chemical Co., Ltd.) in 100 parts by weight of silicone rubber compound KE-941-U (manufactured by Shin-Etsu Chemical Co., Ltd.). An unvulcanized rubber sheet for the pusher portion 30 was produced by dispensing to a thickness of 2.5 mm.

  Also, prepare a metal sheet with Ni and Au plating on the surface, apply primer No18 (manufactured by Shin-Etsu Chemical Co., Ltd.) to the back of the metal sheet, and heat-treat at 200 ° C for 1 hour in a dryer. And put the back side of the metal sheet (primer coated surface) and the unvulcanized rubber sheet together into a 300 mm long, 60 mm wide, 2.0 mm deep mold at 165 ° C. Heated in a pressurized state for 5 minutes to produce a 2.00 mm thick sheet with a metal sheet on one side of the silicone rubber sheet, and punched with a punching die adjusted to punch out to 3 mm in diameter. A pusher portion 30 in which the conductive portion 40 is provided on the end surface 32 on one side of the portion 30 was produced.

  In addition, the thickness of this pusher part 30 is 1.95 mm, the thickness of the conductive part 40 is 0.05 mm, and the hardness of the type A durometer measured by the measuring method of JIS K 6253-3: 2012 of the pusher part 30 The value of is 40.

  In the same manner as in Comparative Example 1, the pusher portion 30 thus prepared was added with 100 parts by weight of a silicone rubber compound KE-971-U (manufactured by Shin-Etsu Chemical Co., Ltd.) and a crosslinking agent C-8 (manufactured by Shin-Etsu Chemical Co., Ltd.) 2 After the pusher portion 30 is disposed in the bottomed recess A1 in the mold using the kneaded material of 0.0 parts by weight as the material of the key top 20 (first material), the pusher portion 30 and the key top portion 23 are integrally fused. The key top 20 was molded to obtain the pushbutton switch 10, but in Example 4, the other end face 31 of the pusher portion 30 was arranged so as to protrude from the bottomed recess A1 in the mold, The push button switch 10 shown in FIG. 4 has the end surface 31 on the other side of the pusher portion 30 entering the key top portion 23.

Specifically, the height (see X in FIG. 4) of the key top portion 23 is 2.0 mm, which is 25%, that is, the end surface 31 on the other side of the 0.5 mm pusher portion 30 is the key top portion. 23 (see Y in FIG. 4).
In Example 4, the pusher portion 30 protrudes from the key top portion 23 toward the 1.45 mm base portion 21 side.
Further, the hardness value of the type A durometer measured by the measuring method according to JIS K 6253-3: 2012 of the key top 20 is 70.

(Example 6)
Example 6 kneads 2.0 parts by weight of a crosslinking agent C-8 (manufactured by Shin-Etsu Chemical Co., Ltd.) in 100 parts by weight of silicone rubber compound KE-922-U (manufactured by Shin-Etsu Chemical Co., Ltd.). The unvulcanized rubber sheet for pusher part 30 was produced by dispensing to a thickness of 3.0 mm.

  Also, prepare a metal sheet with Ni and Au plating on the surface, apply primer No18 (manufactured by Shin-Etsu Chemical Co., Ltd.) to the back of the metal sheet, and heat-treat at 200 ° C for 1 hour in a dryer. And put the back side of the metal sheet (primer coated surface) and the unvulcanized rubber sheet together into a 300 mm long, 60 mm wide, 2.0 mm deep mold at 165 ° C. Heated in a pressurized state for 5 minutes to produce a 2.00 mm thick sheet with a metal sheet on one side of the silicone rubber sheet, and punched with a punching die adjusted to punch out to 3 mm in diameter. A pusher portion 30 in which the conductive portion 40 is provided on the end surface 32 on one side of the portion 30 was produced.

  In addition, the thickness of this pusher part 30 is 1.95 mm, the thickness of the conductive part 40 is 0.05 mm, and the hardness of the type A durometer measured by the measuring method of JIS K 6253-3: 2012 of the pusher part 30 The value of is 20.

  Thereafter, as in Example 4, 2.0 parts by weight of a crosslinking agent C-8 (manufactured by Shin-Etsu Chemical Co., Ltd.) was kneaded with 100 parts by weight of silicone rubber compound KE-971-U (manufactured by Shin-Etsu Chemical Co., Ltd.). The pushbutton switch 10 in which the pusher portion 30 was fused and integrated with the key top portion 23 was manufactured using the material as the key top 20 material (first material).

In the sixth embodiment, as in the fourth embodiment, the height of the key top portion 23 (see X in FIG. 4) is 2.0 mm, which is 25%, that is, on the other side of the 0.5 mm pusher portion 30. The pushbutton switch 10 has an end face 31 that has entered the key top portion 23 (see Y in FIG. 4), and the pusher portion 30 protrudes from the key top portion 23 toward the 1.45 mm base portion 21 side.
In addition, the hardness value of the type A durometer measured by the measuring method according to JIS K 6253-3: 2012 of the key top 20 is 70.

  Table 1 and FIG. 5 show the results of evaluating the characteristics during pressing of the push button switch 10 of Comparative Example 1 and Examples 1 to 6 manufactured as described above.

The hardness of the key top and the pusher part in Table 1 is a hardness value of a type A durometer measured by a measuring method according to JIS K 6253-3: 2012 as described above.
Moreover, the peak ( _FP ) in Table 1 shows the stroke that becomes the peak load and the peak load (N) at that time, and the make (S _O ) shows the stroke that becomes the on-stroke (S _O ) and the load at that time. (N) is shown, and in the return (F _R ), the return load (F _R ) described in FIG. 9 and the stroke at that time are shown.

Furthermore, the overstroke indicates how many strokes are required to reach the full stroke (S _F ) from the make (S _O ) stroke.
Note that the full stroke (S _F ) is a point where the load reaches 10 (N) when the push button switch 10 is pushed down. The load measurement in Table 1 is a load measuring device manufactured by Aiko Engineering Co., Ltd. Measurement was performed using MODEL1013.

  FIG. 5 is a graph of the values in Table 1, but shows only changes in stroke (mm) and load (N) when the pushbutton switch 10 is pressed down for easy viewing. The load change when the push button switch 10 returns to the original state after stopping the lowering is omitted.

As can be seen from Table 1 and FIG. 5, in Comparative Example 1 and Examples 1 to 6, the load change until the make (S 2 _{O 3} ) is substantially the same.
On the other hand, as compared with the case where the key top 20 and the pusher portion 30 of Comparative Example 1 are made of the same hardness material, the hardness of the material of the pusher portion 30 is reduced to be a soft material as in Examples 1-6. as you, as shown in Table 1, to increase the make-distance from (S _O) up to the full stroke (S _F) (see overstroke of Table 1) as indicated by the scope S _F in FIG. 5 It can be seen that the increase in load after the make ( _SO ) indicated by the arrow 3 in FIG.

That is, since the load applied to the operator's finger after the make (S _O ) is moderately increased, the touch of the push button switch 10 given to the operator can be made soft and soft.
From the viewpoint of sufficiently giving this soft feeling to the operator, it is preferable that the pusher portion 30 protrudes 0.45 mm or more from the key top portion 23, more preferably 1.0 mm or more. Further, it is preferable that the protrusion protrudes by 1.5 mm or more.

On the other hand, as described above, the load change from the peak (F _P ) to the make (S _O ) (see arrow 2 in FIG. 5) is almost the same as that in Comparative Example 1, and thus the key top 20 The operator can be given a high click feeling as the hardness of the material is increased.

As described above, according to the present embodiment, it is possible to realize the push button switch 10 having a soft click feeling while obtaining a high click feeling.
In the above description, the conductive portion 40 is provided only on the end surface 32 on one side of the pusher portion 30. However, when the other end surface 31 of the pusher portion 30 enters the key top portion 23, the other side of the pusher portion 30 is provided. Even if the conductive portion 40 is provided on the end surface 31, the key top portion 23 and the pusher portion 30 can be fused and integrated. Therefore, the conductive portion 40 may be provided on the other end surface 31 of the pusher portion 30.

As described above, if the conductive portion 40 is provided on both the end surface 32 on the one side and the end surface 31 on the other side of the pusher portion 30, there is no need to distinguish between the one side and the other side, and there is no bottom in the mold. Since the pusher portion 30 can be disposed in the recess A1, workability can be improved.
Even when the outer shape of the conductive portion 40 is smaller than the end surface of the pusher portion 30, the end surface of the pusher portion 30 and the key top portion 23 can be fused and integrated. Alternatively, the conductive portion 40 may be provided.

(Second Embodiment)
In the first embodiment, the case where the end surface 31 on the other side of the pusher portion 30 is fused and integrated with the key top portion 23 has been described. However, the present invention is not limited to the fusion integration and is shown in the second embodiment. In this way, the adhesive material may be used for bonding and integration.

  Specifically, in the second embodiment, for example, as shown in FIG. 6A, the pusher portion 30 and the key top 20 are separately formed, and the pusher portion 30 is formed on the key top portion 23 as a primer. -Adhesive and integrated with an adhesive material 60 such as an adhesive.

In this case, as in the first embodiment, the base material of the first material for molding the key top 20 and the second material for molding the pusher portion 30 are fused as the same resin-based material, for example. Since there is no need to consider improving the properties, the selection range of materials can be expanded.
However, since it is necessary to bond the pusher portion 30 to a predetermined position of the key top portion 23, the first embodiment is more suitable from the viewpoint of omitting the time and effort of alignment. I can say that.

In the second embodiment, as shown in FIGS. 6 (b) and 6 (c), the key top portion 23 and the pusher portion 30 are integrated with the adhesive material 60 in order to increase the alignment accuracy. A convex portion 26 (see FIG. 6C) or a concave portion 25 (see FIG. 6B) is formed on the key top portion 23 side so as to provide a fitting structure, and the key top portion 23 on the pusher portion 30 side. A concave portion 36 (see FIG. 6C) or a convex portion 35 (see FIG. 6B) that fits into the convex portion 26 or the concave portion 25 may be formed.
In this way, not only alignment can be easily performed with high accuracy, but also the adhesion area can be increased, so that high adhesion can be obtained.

  As shown in FIG. 6B, when the pusher portion 30 is provided with a convex portion 35 and the convex portion 35 is disposed in the key top portion 23, the convex portion 35 is a portion that enters the key top portion 23 side. Therefore, in the same manner as described with reference to FIG. 4 in the first embodiment, the amount of penetration into the key top portion 23 side is 50% or less, more preferably 30% or less. The height of the portion 35 is preferably 50% or less, more preferably 30% or less of the height of the key top portion 23.

Furthermore, as shown in FIG. 6 (d), the flange may be formed on the other end surface 31 to be bonded to the key top portion 23 of the pusher portion 30 so as to be wide. .
By doing in this way, the adhesion area can be increased, so that high adhesion can be obtained.

(Example)
The push button switch 10 having the configuration shown in FIG. 6A was produced as the push button switch 10 of the second embodiment, and the push characteristics were evaluated.
Specifically, 100 parts by weight of a silicone rubber compound KE-941-U (manufactured by Shin-Etsu Chemical Co., Ltd.) is kneaded with 2.0 parts by weight of a cross-linking agent C-8 (manufactured by Shin-Etsu Chemical Co., Ltd.). The unvulcanized rubber sheet for pusher part 30 was produced by dispensing to a thickness of 2.0 mm.

  Also, prepare a metal sheet with Ni and Au plating on the surface, apply primer No18 (manufactured by Shin-Etsu Chemical Co., Ltd.) to the back of the metal sheet, and heat-treat at 200 ° C for 1 hour in a dryer. And put the back of the metal sheet (primer coated surface) and the unvulcanized rubber sheet together into a 300 mm long, 60 mm wide, 1.5 mm deep mold at 165 ° C. Heated in a pressurized state for 5 minutes to produce a 1.50 mm thick sheet with a metal sheet on one side of the silicone rubber sheet, punched with a punching die adjusted to punch out to 3 mm in diameter, and pushed A pusher portion 30 in which the conductive portion 40 is provided on the end surface 32 on one side of the portion 30 was produced.

  In addition, the thickness of this pusher part 30 is 1.45 mm, the thickness of the electroconductive part 40 is 0.05 mm, and the hardness of the type A durometer measured by the measuring method of JIS K 6253-3: 2012 of the pusher part 30 The value of is 40.

  In addition, a material obtained by kneading 2.0 parts by weight of a cross-linking agent C-8 (manufactured by Shin-Etsu Chemical Co., Ltd.) with 100 parts by weight of silicone rubber compound KE-971-U (manufactured by Shin-Etsu Chemical Co., Ltd.) as a key top 20 A key top 20 having a hardness value of 70 of a type A durometer measured by a measuring method according to JIS K 6253-3: 2012 as a material (first material) was molded.

Then, the pusher portion 30 was bonded and integrated with the key top portion 23 of the key top 20 using an adhesive (Super X No. 8008 manufactured by Cemedine Co., Ltd.) on the other end surface 31 of the pusher portion 30.
When the pressing characteristics were evaluated, the same characteristics as in Example 4 could be obtained.

As mentioned above, although the pushbutton switch of this invention has been demonstrated based on specific embodiment, this invention is not limited to the said embodiment.
For example, as in the modification shown in FIG. 7, a dome-shaped conductive portion 55 (such as a metal dome / PET dome formed with a conductive layer) may be provided in advance on the substrate 50 side. Therefore, it is not necessary to provide the conductive portion in the pusher portion 30, and therefore providing the conductive portion 40 is not an essential requirement.
Thus, the present invention is not limited to a specific embodiment, and it goes without saying that modifications and improvements can be made without departing from the technical idea of the present invention. It will be clear to the person skilled in the art from the description of the scope of claims.

DESCRIPTION OF SYMBOLS 10 Pushbutton switch 20 Key top 21 Base part 22 Dome part 23 Key top part 30 Pusher part 40 Conductive part

Claims (14)

A key top in which a dome portion and a base portion and a key top portion connected by the dome portion are integrally formed of a first material;
A pusher portion formed of a second material provided so as to protrude from the key top portion toward the base portion,
The push button switch, wherein the second material is made of a softer material than the first material.   The hardness value of the type A durometer measured by the measurement method according to JIS K 6253-3: 2012 of the first material is X, and the measurement is performed by the measurement method according to JIS K 6253-3: 2012 of the second material. When the hardness value of the type A durometer is Y, the second material is a soft material having a value W obtained by subtracting the hardness Y of the second material from the hardness X of the first material is 5 or more. The pushbutton switch according to claim 1, wherein the pushbutton switch is made of a material.   3. The pushbutton switch according to claim 1, wherein the pusher portion protrudes 0.45 mm or more from the key top portion toward the base portion. 4.   4. The pushbutton switch according to claim 1, wherein a contact portion of the key top portion and the pusher portion is fused and integrated. 5.   5. The pushbutton switch according to claim 4, wherein the first material and the second material are silicone rubber.   The pushbutton switch according to any one of claims 1 to 3, wherein the key top portion and the pusher portion are bonded and integrated with an adhesive material.   In the part integrated with the adhesive material of the key top part and the pusher part, a convex part or a concave part is formed on the key top part side and fitted into the convex part or concave part of the key top part on the pusher part side. The push button switch according to claim 6, wherein a concave portion or a convex portion is formed.   The push button according to any one of claims 1 to 7, wherein the pusher portion has an amount of entering the key top portion side of 50% or less of the height of the key top portion. switch.   The push button according to any one of claims 1 to 8, wherein a conductive portion is provided on at least one end face of the pusher portion located on the opposite side to the key top portion. switch.   The push button switch according to claim 9, wherein the conductive portion has an outer shape equal to or smaller than an outer shape of the end face of the pusher portion provided with the conductive portion. A pusher part molding step of molding the pusher part with a second material made of a softer material than the first material;
The dome portion and a base portion and a key top portion connected by the dome portion are protruded from the key top portion toward the base portion in the key top portion of the key top integrally formed with the first material. And an integration step of integrating the pusher portion.   The hardness value of the type A durometer measured by the measurement method according to JIS K 6253-3: 2012 of the first material is X, and the measurement is performed by the measurement method according to JIS K 6253-3: 2012 of the second material. When the hardness value of the type A durometer is Y, the second material is a soft material having a value W obtained by subtracting the hardness Y of the second material from the hardness X of the first material is 5 or more. The method of manufacturing a pushbutton switch according to claim 11, wherein the pushbutton switch is made of a new material.   13. In the integration step, the pusher portion is integrated with the key top portion so as to protrude 0.45 mm or more from the key top portion toward the base portion. The manufacturing method of the pushbutton switch of description. The first material and the second material are materials of different hardness with the same resin base material,
The integration step includes
When the key top is molded by heating the first material in a pressurized state in the internal space of the mold, the first material is disposed in a bottomed recess formed in the mold that opens into the internal space. The method for manufacturing a pushbutton switch according to any one of claims 11 to 13, wherein the pusher portion is a step of fusing and integrating with the key top portion.

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