JP6829619B2 - Push button switch member and its manufacturing method - Google Patents

Description

The present invention relates to a member for a push button switch and a method for manufacturing the same.

As switches for a wide variety of devices such as in-vehicle devices, communication devices, audio devices, and household electric devices, push button switch members having a pressing portion, a thin-walled movable portion, and a base portion (see, for example, Patent Documents 1, 2, and 3). ) Is known. The structure of a member similar to the push button switch member disclosed in these patent documents will be described below with reference to the drawings.

FIG. 9 is a vertical cross-sectional view (9A) of a conventionally known first push button switch member, a vertical cross-sectional view (9B) of a conventionally known second push button switch member, and a conventionally known third push button. The vertical sectional view (9C) of the switch member is shown respectively.

The first push button switch member 101 includes a thin-walled movable portion 102 made of a rubber-like elastic body such as silicone rubber, and a pressing portion 104 made of a thermosetting resin bonded to the upper surface thereof without interposing an adhesive or the like. A protruding portion 103 that projects downward from the lower surface of the thin-walled movable portion 102 and functions as a contact point. The second push button switch member 111 includes the above-mentioned thin-walled movable portion 102 and a pressing portion 112 formed of a rubber-like elastic body having a hardness higher than that of the thin-walled movable portion 102, which is joined to the upper surface thereof without interposing an adhesive or the like. , With a protruding portion 103. The third push button switch member 121 has substantially the same structure as the first push button switch member 101, and has a structure in which the thin-walled movable portion 102 and the pressing portion 104 are adhered by an adhesive layer 122.

On the other hand, as a conventionally known fourth push button switch member (not shown), a molded body including at least a pressing portion and a thin movable portion is produced from a rubber-like elastic body such as silicone rubber, and ultraviolet rays are applied to the pressing portion. It is also known that the hardness is increased by irradiation (see, for example, Patent Document 4).

Japanese Unexamined Patent Publication No. 9-6748 Jikkenwa 60-87125 Japanese Unexamined Patent Publication No. 2006-252816 Japanese Unexamined Patent Publication No. 7-238177

The conventionally known push button switch members 101, 111, 121 have excellent functions as push button switch members, but there is also a demand in the market for a more excellent push button switch member. One of them is to prevent the pressing portion 104 and the thin-walled movable portion 102 from peeling off. There is also a demand for a thinner pressing portion. In order to meet these demands, Patent Document 4 describes that the pressing portion and the thin-walled movable portion are made of the same rubber-like elastic body (silicone rubber, etc.) to reduce the adhesiveness peculiar to rubber and to increase the hardness. There is also disclosure technology. However, there is a desire to maintain low adhesiveness and high hardness of the pressed portion for a long period of time by reducing the adhesiveness and increasing the hardness to a portion deeper than the irradiation with ultraviolet rays.

The present invention has been made to solve the above problems, and can prevent peeling between the pressing portion and the thin-walled movable portion, realize a thin pressing portion, and maintain low adhesiveness and high hardness of the pressing portion for a long period of time. The purpose is to provide a member for a sustainable push button switch.

[1] The method for manufacturing a push button switch member according to an embodiment for achieving the above object is a pressing portion, a thin-walled movable portion connected to the outer periphery of the pressing portion, and a base portion connected to the outer periphery of the thin-walled movable portion. The pressing portion protrudes to one side with respect to the base portion, and at least the pressing portion and the thin-walled movable portion are made of the same type of rubber-like elastic body, and at least a part of the top surface of the pressing portion is formed. This is a method for manufacturing a push button switch member whose rubber hardness in some parts including is higher than that in other parts. At least the pressing part and the thin movable part are formed of a rubber-like elastic body to form a push button switch member. It includes a forming step of forming the element body and an irradiation step of irradiating a part of the pressing portion of the element body with an electron beam to make the part of the pressing portion harder than the other parts.

[2] In the method for manufacturing the push button switch member according to another embodiment, the irradiation dose of the electron beam may be further set to 100 kGy or more in the irradiation step.

[3] In the method for manufacturing the push button switch member according to another embodiment, the irradiation dose of the electron beam may be further set to the irradiation dose in the range of 100 kGy to 1200 kGy in the irradiation step.

[4] In the method for manufacturing the push button switch member according to another embodiment, the irradiation dose of the electron beam may be further set to the irradiation dose in the range of 100 kGy to 600 kGy in the irradiation step.

[5] In the method for manufacturing a member for a push button switch according to another embodiment, the rubber-like elastic body is made to contain silicone rubber, and the forming step is carried out by heating an element body containing silicone rubber containing a cross-linking agent to crosslink. It may be a step to do.

[6] In the method for manufacturing a member for a push button switch according to another embodiment, the rubber-like elastic body is made to contain silicone rubber, and the forming step is performed by applying an electron beam to the element body containing silicone rubber containing no cross-linking agent. It may be a step of irradiating and cross-linking.

[7] Further, the push button switch member according to the embodiment includes a pressing portion, a thin-walled movable portion connected to the outer periphery of the pressing portion, and a base portion connected to the outer periphery of the thin-walled movable portion, and the pressing portion is a base. It protrudes to one side with reference to the part, and at least the pressing part and the thin-walled movable part are made of the same type of rubber-like elastic body, and the rubber hardness of at least a part of the pressing part is higher than the rubber hardness of the other part. high.

[8] In the push button switch member according to another embodiment, the rubber hardness of at least a part of the pressing portion may be 30% or more higher than the rubber hardness of the other portion.

[9] In the push button switch member according to another embodiment, at least a part of the pressing portion may be the entire region of the pressing portion, and the rubber hardness of the entire region may be higher than the rubber hardness of the other portion. ..

[10] In the push button switch member according to another embodiment, the rubber-like elastic body may also contain silicone rubber.

[11] In the push button switch member according to another embodiment, the base portion is provided with a plurality of thin-walled movable portions, and the pressing portion is provided above the thin-walled movable portion, and a part of the one or a plurality of pressing portions. The rubber hardness of the portion may be higher than the rubber hardness of a part of the other one or a plurality of pressing portions.

According to the present invention, it is possible to prevent peeling between a pressing portion and a thin movable portion, realize a thin pressing portion, and provide a member for a push button switch that can maintain low adhesiveness and high hardness of the pressing portion for a long period of time. ..

FIG. 1 shows a vertical sectional view (1A) and a plan view (1B) of the push button switch member according to the first embodiment, respectively. FIG. 2 shows a flowchart of a method for manufacturing a push button switch member according to the first embodiment. FIG. 3 shows a method of manufacturing a push button switch member according to the first embodiment. FIG. 4 shows a vertical cross-sectional view of the push button switch member according to the second embodiment. FIG. 5 shows a vertical sectional view (5A) and a plan view (5B) of the push button switch member according to the third embodiment, respectively. FIG. 6 shows a vertical sectional view (6A) and a plan view (6B) of the push button switch member according to the fourth embodiment, respectively. FIG. 7 shows a vertical sectional view (7A) and a plan view (7B) of the push button switch member according to the fifth embodiment, respectively. FIG. 8 shows a vertical cross-sectional view of the element body for the push button switch member used in each Example and Comparative Example. FIG. 9 is a vertical cross-sectional view (9A) of a conventionally known first push button switch member, a vertical cross-sectional view (9B) of a conventionally known second push button switch member, and a conventionally known third push button. The vertical sectional view (9C) of the switch member is shown respectively.

Next, each embodiment of the push button switch member and the manufacturing method thereof according to the present invention will be described with reference to the drawings. It should be noted that the embodiments described below do not limit the invention according to the claims. Moreover, not all of the elements and combinations thereof described in each embodiment are essential for the solution of the present invention. In each embodiment, for components having the same basic configuration and features, the same reference numerals may be used across the embodiments, and the description may be omitted.

(First Embodiment)
First, a push button switch member and a manufacturing method thereof according to the first embodiment will be described.

FIG. 1 shows a vertical sectional view (1A) and a plan view (1B) of the push button switch member according to the first embodiment, respectively.

The push button switch member 1 according to the first embodiment includes a pressing portion 10, a thin-walled movable portion 20 connected to the outer periphery of the pressing portion 10, and a base portion 30 connected to the outer periphery of the thin-walled movable portion 20. The pressing portion 10, the thin-walled movable portion 20, and the base portion 30 are preferably made of the same type of rubber-like elastic body. Further, the base portion 30 may be made of a material (any of a rubber-like elastic body, a thermoplastic resin, or a thermosetting resin) different from the material constituting the pressing portion 10 and the thin-walled movable portion 20. In that case, at least the pressing portion 10 and the thin-walled movable portion 20 are made of the same type of rubber-like elastic body. The pressing portion 10, the thin-walled movable portion 20, and the base portion 30 may be separately molded and joined, or may be integrally molded. In the present specification, the meaning of "consisting of the same type of rubber-like elastic body" means that the materials of the rubber-like elastic body before or during molding are the same.

In the first embodiment and other embodiments described later, the rubber-like elastic body preferably includes urethane rubber, isoprene rubber, ethylene propylene rubber, natural rubber, ethylene propylene diene rubber, and nitrile rubber, in addition to silicone rubber. Examples of thermosetting elastomers such as (NBR) or styrene butadiene rubber (SBR), thermoplastic elastomers such as urethane-based, ester-based, styrene-based, olefin-based, butadiene-based, and fluorine-based, or composites of the above. it can. Among these illustrated rubber-like elastic bodies, silicone rubber is particularly preferable. Further, the rubber-like elastic body may contain a filler such as silica.

The pressing portion 10 projects to one side with reference to the base portion 30. In this embodiment, one side is the upper side or the front side corresponding to the side opposite to the circuit board when the push button switch member 1 is installed on the circuit board or the like. In the first embodiment and other embodiments described later, the pressing portion 10 is a cylindrical constituent member having a circular shape in a plan view. Depending on the installation location of the push button switch member 1, it may be referred to in another direction such as the left side or the right side instead of the upper side or the front side.

The rubber hardness of at least a part 15 of the pressing portion 10 is higher than the rubber hardness of the other parts. In this embodiment, as an example, a part of the portion 15 is a region from the entire top surface of the pressing portion 10 to a predetermined depth (a position in the middle of the thickness of the pressing portion 10 in the vertical direction) toward the lower side thereof. is there. However, the portion 15 of the pressing portion 10 is not limited to the above region shown in FIG. 1 as long as it includes at least a portion of the top surface. The rubber hardness of at least a part 15 of the pressing portion 10 is higher than the rubber hardness of other parts other than the part 15, and more preferably 30% or more. Here, the rubber hardness refers to the rubber hardness measured by a type A durometer conforming to JIS K 6253. In other figures including FIG. 1, some parts 15 are displayed in light ink (gray color) in order to distinguish them from other parts. In the cross-sectional views of FIGS. 1 and 1 and thereafter, hatching such as diagonal lines is omitted from the viewpoint of making it easier to see some parts 15. “Other location” means an electron beam non-irradiated region that is not irradiated with an electron beam, which will be described later. Therefore, the other portions are the pressing portion 10, the thin-walled movable portion 20, and the base portion 30, which are not irradiated with the electron beam, that is, the portions that have not been hardened. When the base portion 30 is made of a material different from that of the pressing portion 10 and the thin-walled movable portion 20, the base portion 30 is not included in other parts.

In this embodiment, the upper region of the pressing portion 10 in the vertical thickness direction is referred to as "at least a part of the portion". Therefore, the upper region of the pressing portion 10 has a higher rubber hardness than the lower region located below the upper region of the pressing portion 10. The rubber hardness of some parts 15 is preferably 30% or more higher than the rubber hardness of other parts, more preferably 30% or more and 125% or less, and 30% or more and 95% or less. Higher is even more preferable. It is preferable to make the rubber hardness of some parts 15 higher than the rubber hardness of other parts by 30% or more, which reduces the adhesiveness when the top surface of the pressing portion 10 is pressed and has high scratch resistance. This is because the sex can be secured. Further, it is more preferable to set the upper limit of the rubber hardness in the range of 125% or less, more preferably in the range of 95% or less, because the probability of cracks or the like occurring on the top surface of the pressing portion 10 can be reduced. However, such an upper limit is not indispensable, and the above upper limit is not required when the possibility of cracking is low or the yield of the product is not a concern due to the selection of the rubber-like elastic body.

The protruding portion 12 is a member that protrudes from the lower side (or back side) of the pressing portion 10 toward the circuit board or the like. When the push button switch member 1 is incorporated into the push button switch, the protruding portion 12 comes into contact with a component (for example, an electrode, a metal dome, or another type of switch) arranged directly under the pressing portion 10 to turn on the switch.・ It becomes a part that can be turned off. The protruding portion 12 is a cylindrical member having a circular plan view shape in the first embodiment and other embodiments described later. The protruding portion 12 may be integrated with the pressing portion 10 or may be a separate body. When the protruding portion 12 is separate from the pressing portion 10, for example, the protruding portion 12 is preferably adhered to the back side of the pressing portion 10. Further, the protruding portion 12 may be made of a conductive substance (for example, a metal or a conductive rubber-like elastic body). The protruding portion 12 is not included in other portions.

The thin-walled movable portion 20 is a member connected to the outer periphery of the pressing portion 10. The thin-walled movable portion 20 is preferably formed to be thinner than the pressing portion 10 and the base portion 30. The thin-walled movable portion 20 is an elastically deforming member that elastically deforms when the pressing portion 10 is pressed toward a circuit board or the like and returns to its original shape when the pressing on the pressing portion 10 is released. The thin-walled movable portion 20 is a portion included in other portions and has a rubber hardness lower than the rubber hardness of a part portion 15 of the pressing portion 10.

The base portion 30 is connected to the outer circumference of the thin-walled movable portion 20. The base portion 30 is a portion for fixing the push button switch member 1 to a circuit board or the like when the push button switch member 1 is incorporated into the push button switch. In the first embodiment and other embodiments, the top view shape of the base portion 30 is a quadrangle. The base portion 30 may be formed with holes, protrusions, or the like for mounting.

Next, a method of manufacturing the push button switch member according to the first embodiment will be described.

FIG. 2 shows a flowchart of a method for manufacturing a push button switch member according to the first embodiment. FIG. 3 shows a method of manufacturing a push button switch member according to the first embodiment. FIG. 3A is a vertical cross-sectional view after the element body forming step, FIG. 3B is a vertical cross-sectional view of the element body when irradiating an electron beam in the irradiation step, and FIG. 3C is a vertical cross-sectional view. It is a vertical cross-sectional view of the push button switch member after an irradiation process.

The method for manufacturing a push button switch member according to the first embodiment is a forming step in which the pressing portion 10, the thin-walled movable portion 20, and the base portion 30 are formed of a rubber-like elastic body to form the element body 1a of the push button switch member 1. (S100) and a part 15 of the pressing portion 10 in the element body 1a are irradiated with the electron beam e, and the part 15 is changed to another part (in this embodiment, a part of the pressing portion 10). The region below 15, the thin-walled movable portion 20 and the base portion 30) include an irradiation step (S200) to make the hardness higher than that of the base portion 30). The method for manufacturing the push button switch member 1 may further include other steps as long as the forming step S100 and the irradiation step S200 are included.

(1) Forming step S100
As shown in FIG. 3A, the forming step S100 is a step of forming the pressing portion 10, the thin-walled movable portion 20, and the base portion 30 with a rubber-like elastic body to form the element body 1a of the push button switch member 1. is there. However, the base portion 30 may not be included.

In the first embodiment, the rubber-like elastic body contains silicone rubber. The forming step S100 is preferably a step of heating a silicone rubber containing a cross-linking agent to form a connecting body of the pressing portion 10, the thin-walled movable portion 20, and the base portion 30. Further, as a modification, the forming step S100 is a step of irradiating a silicone rubber element body 1a composed of a pressing portion 10, a thin-walled movable portion 20 and a base portion 30 and containing no cross-linking agent with an electron beam to form the molding step S100. Is also good. Since the cross-linking agent and the electron beam have the effect of promoting the cross-linking of the silicone rubber, an appropriate molding method can be selected according to the type of the push button switch member 1 and the properties of the raw material. As a method for molding the pressing portion 10, the thin-walled movable portion 20, and the base portion 30, a method using a molding die can be preferably selected.

Further, when the protruding portion 12 is integrated with the pressing portion 10, the protruding portion 12 can also be integrally formed with the pressing portion 10 and the like. On the other hand, when the protruding portion 12 is separate from the pressing portion 10, for example, the protruding portion 12 may be adhered to the pressing portion 10 after molding the element body 1a. The adhesion may be carried out in the forming step, or may be carried out during the step by providing another step. In the first embodiment, the protruding portion 12 is a separate body from the pressing portion 10, and is adhered to the pressing portion 10 in the forming step.

(2) Irradiation step S200
As shown in FIG. 3B, the irradiation step S200 is a step of irradiating a part 15 of the element body 1a with an electron beam e to increase the hardness of the part 15. In the irradiation step S200 of this embodiment, the electron beam e is irradiated to the top surface of the pressing portion 10. By adjusting the acceleration voltage or irradiation time of the electron beam e, the thickness of a part of the portion 15 can be adjusted. The acceleration voltage of the electron beam e can be, for example, 200 kV to 500 kV. The irradiation time of the electron beam e is 3 seconds or less, preferably 2.5 seconds or less, more preferably 2.3 seconds or less, and even more preferably 2.0 seconds or less. Productivity can be improved by shortening the irradiation time of the electron beam e.

In the irradiation step S200, the irradiation dose of the electron beam e is preferably 100 kGy or more, more preferably 100 kGy to 1200 kGy, and even more preferably 100 kGy to 600 kGy. By setting the irradiation dose of the electron beam e to 100 kGy or more, the cross-linking of a part of the portion 15 can be sufficiently advanced and the hardness can be increased. Further, by setting the upper limit of the irradiation dose of the electron beam e to 1200 kGy and further to 600 kGy, it is possible to effectively prevent cracks and the like in some parts 15. In addition, in order to increase the irradiation dose, the electron beam e may be irradiated to the same position a plurality of times.

Further, instead of the electron beam e, for example, vacuum ultraviolet rays having a wavelength of 172 nm may be used. However, since the transparency of the electron beam e is not affected by the color (optical characteristics) of the substance, it is superior to the above-mentioned vacuum ultraviolet rays.

(Second Embodiment)
Next, the push button switch member and the manufacturing method thereof according to the second embodiment will be described. The push button switch member according to the second embodiment is different from the first embodiment in that its hardness is higher than that of other parts (thin-walled movable part and base part) over the entire thickness of the pressing part in the vertical direction. .. Further, the method for manufacturing the push button switch member according to the second embodiment is the first embodiment in that the irradiation dose of the electron beam irradiated from the top surface of the pressing portion is larger than that in the manufacturing method of the first embodiment. Different from the form. Since the parts other than these points are common to the first embodiment, the description and illustration of the common parts will be omitted.

FIG. 4 shows a vertical cross-sectional view of the push button switch member according to the second embodiment.

In the push button switch member 2 according to this embodiment, the entire region of the pressing portion 10 is a part portion 15 having a hardness higher than the hardness of other portions (thin-walled movable portion 20 and base portion 30). A part of the hardened portion 15 is formed in a portion from the entire top surface of the pressing portion 10 to the lower surface (the surface in contact with the protruding portion 12).

The push button switch member 2 according to this embodiment can be manufactured through the same manufacturing process as the push button switch member 1 according to the first embodiment. However, the irradiation step S200 is different from that of the first embodiment. In the irradiation step S200 of this embodiment, the acceleration voltage and / or the irradiation time of the electron beam e is further increased so that the cross-linking proceeds further in the vertical thickness direction of the pressing portion 10. In this way, the push button switch member 2 has a high hardness in the entire area of the pressing portion 10, so that the surface of the pressing portion 10 is worn away and increased by repeating the pressing operation of the pressing portion 10 with use for a long period of time. It is possible to prevent the situation where the hardened region disappears and a sticky feeling is generated.

(Third Embodiment)
Next, the push button switch member and the manufacturing method thereof according to the third embodiment will be described. The push button switch member according to the third embodiment is different from the first embodiment in that the hardness of the push button switch member is increased to an intermediate position in the thickness direction except for a part of the top surface of the pressing portion. Further, the method for manufacturing the push button switch member according to the third embodiment is different from the first embodiment in that a part of the top surface of the pressing portion is not irradiated with an electron beam. Since the parts other than these points are common to the first embodiment, the description and illustration of the common parts will be omitted.

FIG. 5 shows a vertical sectional view (5A) and a plan view (5B) of the push button switch member according to the third embodiment, respectively.

The push button switch member 3 according to this embodiment has other parts (lower region of the pressing portion 10, thin-walled movable portion 20) except for the character region 16 of "A" exemplified as a part of the top surface of the pressing portion 10. And a part 15 having a hardness higher than the hardness of the base portion 30). A part of the hardened portion 15 is formed from the top surface of the pressing portion 10 to an intermediate position in the thickness direction. In this embodiment, in the plan view of the pressing portion 10, the non-hardness region in the depth direction from the character region 16 is formed only above the thickness of a part of the portion 15. However, a non-hardness region may be formed from the character region 16 to a part of the portion 15 over the entire length in the vertical depth direction. In particular, when a part 15 which is a high hardness region is formed in an extremely thin region from the top surface of the pressing portion 10, the character region 16 to the part 15 are not formed over the entire length in the vertical depth direction. High hardness region is likely to be formed. On the other hand, when a part of the portion 15 which is the hardness increasing region is formed to have a thickness from the top surface to the bottom surface of the pressing portion 10 (see the second embodiment), a part of the character region 16 is formed. A part of the portion 15 in the vertical depth direction is likely to be formed in the non-hardness region.

When increasing the hardness of the pressing portion 10 so as to exclude the character region 16, a method of irradiating the electron beam e while avoiding the character region 16 in the irradiation step (S200), or a material for shielding the character region 16 from the electron beam e. It is preferable to adopt a method of irradiating the entire top surface of the pressing portion 10 with the electron beam e by masking with.

(Fourth Embodiment)
Next, the push button switch member and the manufacturing method thereof according to the fourth embodiment will be described. The push button switch member according to the fourth embodiment has a structure in which two switch parts having different thicknesses at a part of each hardened portion in the two pressing portions are connected in the horizontal direction. Since the push button switch member according to the fourth embodiment is common to that of the first embodiment except for the above points, the description and illustration of the common parts will be omitted.

FIG. 6 shows a vertical sectional view (6A) and a plan view (6B) of the push button switch member according to the fourth embodiment, respectively.

As shown in FIG. 6, the push button switch member 4 according to the fourth embodiment includes a first switch component 4a having a pressing portion 10a, a protruding portion 12a, and a thin movable portion 20a, and a pressing portion 10b and a protruding portion 12b. It has a structure in which the second switch component 4b provided with the thin-walled movable portion 20b is connected in the horizontal direction in a form of sharing the base portion 30.

The pressing portion 10a of the first switch component 4a has a thin ink region that exceeds the position of half of the top surface in the vertical thickness direction at other locations (a region below the thin ink region of the pressing portion 10a, a thin movable portion 20a, and a base portion 30). It is provided with a part portion 15a having a higher hardness than that. On the other hand, the second switch component 4b has a thin ink region above the top surface in the vertical thickness direction half of the top surface at other locations (a region below the thin ink region of the pressing portion 10b, a thin movable portion 20b and a base portion 30). It is provided with a part of the portion 15b having a higher hardness than that of the above. That is, when the pressing portion 10a and the pressing portion 10b are compared, a part of the portion 15b as the hardness-increasing region formed in the pressing portion 10b is one as the hardness-increasing region formed in the pressing portion 10a. It is thinner than the part 15a. In the present application, such different forms of the hardness-enhancing region are referred to as "forms in which the patterns of some parts are different". That is, "a form in which the pattern of some parts is different" means that when one pressing part 10a and another pressing part 10b are compared, the positions of some parts 15a and 15b formed there or It means that the size and the like are not the same but different forms. In the push button switch member 4, the base portion 30 is provided with two thin-walled movable portions 20a and 20b, and the pressing portions 10a and 10b are provided above the thin-walled movable portions 20a and 20b, and a part of the pressing portion 10a. The rubber hardness of the portion 15a may be higher or lower than the rubber hardness of some portions 15b in the other pressing portion 10b.

The push button switch member 4 has basically the same manufacturing method as the push button switch member manufacturing method according to the first embodiment, that is, the element body (pressing portion) corresponding to the push button switch member 4 in the forming step S100. It can be manufactured by a method of forming 10a, 10b, a molded body including thin-walled movable portions 20a, 20b, and a base portion 30), and forming some portions 15a, 15b in the subsequent irradiation step S200. In order to form some of the locations 15a and 15b having different morphologies from each other, it is preferable to change the irradiation dose for irradiating the electron beam e at the time of formation.

(Fifth Embodiment)
Next, the push button switch member and the manufacturing method thereof according to the fifth embodiment will be described. The push button switch member according to the fifth embodiment is the fourth embodiment except that the second switch component of the fourth embodiment is replaced with a third switch component having a pressing portion which is not hardened at all. It is common with the push button switch member. Therefore, the description and illustration of the common part will be omitted.

FIG. 7 shows a vertical sectional view (7A) and a plan view (7B) of the push button switch member according to the fifth embodiment, respectively.

As shown in FIG. 7, the push button switch member 5 according to the fifth embodiment includes a first switch component 5a having a pressing portion 10a, a protruding portion 12a, and a thin movable portion 20a, and a pressing portion 10c and a protruding portion 12c. It has a structure in which a third switch component 5c having a thin-walled movable portion 20c and a third switch component 5c are connected in the horizontal direction in a form sharing the base portion 30.

The push button switch member 5 includes a part of the portion 15a in a region extending from the top surface of the pressing portion 10a of the first switch component 5a to a position beyond the middle in the vertical thickness direction. The part 15a is a part having a higher hardness than the other parts (the region below the part 15a of the pressing portion 10a, the thin-walled movable portion 20a and the base portion 30). The first switch component 5a has the same form as the first switch component 4a of the fourth embodiment. On the other hand, the pressing portion 10c of the third switch component 5c is not hardened at all and does not have a portion corresponding to a part of the portion 15a. As described above, the push button switch member 5 includes a part portion 15a only in a part of the switch parts (the first switch part 5a in this embodiment), and the other switch parts (in this embodiment, the third switch part 5a). A form in which a part of the switch component 5c) is not provided is also referred to as "a form in which the pattern of some parts is different" in the present application. That is, "a form in which the pattern of some parts is different" means that when one pressing portion 10a and another pressing portion 10c are compared, the position or size of some parts formed therein, etc. Is not the same, but different forms.

The push button switch member 5 has basically the same manufacturing method as the push button switch member manufacturing method according to the first embodiment, that is, the element body (pressing portion) corresponding to the push button switch member 5 in the forming step S100. 10a, 10c, a molded body including thin-walled movable portions 20a, 20c, and a base portion 30), and in the subsequent irradiation step S200, a part of the portion 15a is formed only on one pressing portion 10a. be able to.

(Other embodiments)
Although the preferred embodiments of the present invention have been described above, the push button switch member according to the present invention can be modified in various ways as described below without being restricted by the respective embodiments.

Pressing portions 10, 10a, 10b, 10c (referred to as pressing portion 10 and the like), protruding portions 12, 12a, 12b and 12c (referred to as pressing portion 12 and the like), thin-walled movable portions 20, 20a, 20b and 20c in each of the above-described embodiments. Each shape of the base portion 30 (referred to as a thin-walled movable portion 20 or the like) is an example, and various shapes can be obtained according to the intended use or the like. Further, the plan-view shapes of the pressing portion 10 and the like, the protruding portion 12 and the like, and the thin-walled movable portion 20 and the like do not have to be the same, and for example, the plan-view shapes of the pressing portion 10 and the like and the protruding portion 12 and the like are made circular. The plan view shape of the outer edge portion of the thin-walled movable portion 20 or the like may be a quadrangle. On the contrary, the plan-view shapes of the pressing portion 10 and the like, the protruding portion 12 and the like, the thin-walled movable portion 20 and the like may all be the same circle or the same quadrangle.

Some of the locations 15, 15a and 15b are examples and can be formed at various positions or sizes according to the intended use.

In the above-described fourth embodiment, the number of the pressing portions 10a and 10b and the number of the thin-walled movable portions 20a and 20b are only two, but the number may be three or more. This also applies to the fifth embodiment. Further, in such a case, the rubber hardness of a part of the one or more pressing portions may be higher than the rubber hardness of a part of the other pressing portion. Further, in the fourth embodiment and the fifth embodiment, the push button switch members 4 and 5 sharing the base portion 30 are illustrated, but the first switch component 4a and the second switch component 4b have different bases, respectively. A portion 30 may be provided, or a separate base portion 30 may be provided for each of the first switch component 5a and the third switch component 5c.

In each of the above-described embodiments, the rubber-like elastic body contains silicone rubber, but it does not necessarily have to contain silicone rubber. The rubber-like elastic body may be a material that can increase the rubber hardness by irradiation with an electron beam e and that is elastically deformable and suitable for switch operation.

Further, the components of the push button switch members 1 to 5 (referred to as push button switch members 1 and the like) in each embodiment and each modification can be arbitrarily combined with each other except when they cannot be combined. For example, the push button switch member 2 (see FIG. 4) according to the second embodiment is the first switch component 4a or the second switch component 4b of the push button switch member 4 (see FIG. 6) according to the fourth embodiment. May be substituted for. Similarly, the push button switch member 3 (see FIG. 5) according to the third embodiment is the first switch component 5a or the third switch component of the push button switch member 5 (see FIG. 7) according to the fifth embodiment. It may be substituted for 5c.

Next, examples of the present invention will be described with reference to the drawings. However, the present invention is not restricted to the following examples.

(Examples 1 to 6 and Comparative Example 1)
(1) Form of Element Body for Push Button Switch Member FIG. 8 shows a vertical cross-sectional view of the element body for the push button switch member used in each Example and Comparative Example.

The element body 1b was made of silicone rubber. Here, the diameter a of the cylindrical pressing portion 10 constituting the element body 1b is 3.5 mm. The height b from the top surface of the pressing portion 10 of the body 1b to the bottom surface of the base portion 30 is 2.6 mm. The distance c from the bottom surface of the protruding portion 12 to the bottom surface of the base portion 30 is 0.8 mm. The thickness d of the base portion 30 is 0.7 mm. The diameter e of the lower opening surface of the thin-walled movable portion 20 is 5.2 mm. The wall thickness of the thin movable portion 20 is 0.23 mm. In order to confirm the effect of the irradiation dose of the electron beam, a plurality of element bodies 1b were formed.

(2) Method for Manufacturing Element Body of Push Button Switch Member First, the element body 1b shown in FIG. 8 was formed by a method corresponding to the forming step S100 in the first embodiment. As a curable silicone rubber composition (mirable compound) for forming the element body 1b, C manufactured by Shin-Etsu Chemical Co., Ltd. as a vulcanizing agent for 100 parts by mass of KE-941-U (product number). -8 (Product No.) 2 parts by mass was added. The element body 1b was molded using a mold. Curing was performed by a 10-minute primary vulcanization at 175 ° C. and a subsequent 60-minute secondary vulcanization at 200 ° C. After the molding, the protruding portion 12 was adhered to the lower surface of the pressing portion 10 to complete the element body 1b.

(3) Method for increasing hardness of thin-walled movable portion The pressing portion 10 of the element body 1b was irradiated with an electron beam under various conditions. An electron beam irradiation device (model: EPS-3000) manufactured by NHV Corporation was used for electron beam irradiation. The electron beam was applied to the top surface of the pressing portion 10. The acceleration voltage of the electron beam was 3000 kV. The beam current was 12.9 mA, and the processing speed of electron beam irradiation was 3 m / min.

The irradiation dose of the electron beam was changed in 7 steps within the range of 0 to 1200 kGy to complete the push button switch member. Comparative Example 1 when no electron beam was irradiated (irradiation dose: 0 kGy), Example 1 when the irradiation dose was 100 kGy, Example 2 when the irradiation dose was 200 kGy, and the case where the irradiation dose was 300 kGy. Example 3, the case where the irradiation dose of 600 kGy was irradiated was referred to as Example 4, the case where the irradiation dose of 900 kGy was irradiated was designated as Example 5, and the case where the irradiation dose of 1200 kGy was irradiated was designated as Example 6.

(4) Evaluation of Elementary Body The rubber hardness and sensory evaluation of each pressing portion 10 were performed on a plurality of elemental bodies 1b produced under the above conditions. The rubber hardness was determined by measuring with a Type A durometer conforming to JIS K 6253. The rubber hardness was measured at three points for each sample, and the average value was taken as the rubber hardness of the sample. The rubber hardness thus obtained means the hardness “before irradiation” in Table 1 described later.

(5) Evaluation of push button switch members The rubber hardness of the pressing portion 10 was measured for seven types of push button switch members manufactured by changing the irradiation dose. The measurement conditions are the same as before irradiation with the electron beam. The measured rubber hardness means the hardness “after irradiation” in Table 1. Further, with respect to the above seven types of push button switch members, the tack feeling when the top surface of the pressing portion 10 was pressed was evaluated (sensory test). In such a sensory test, the tack feeling is large when the tack feeling (also called adhesive feeling) is hardly felt as "◎" and when the tack feeling is slightly felt but the operation feeling is not adversely affected. The case where the operation feel is uncomfortable is marked with "x".

Since the wear resistance, compression set, and oil resistance of the push button switch member prepared by changing the irradiation dose cannot be measured directly, a sample having a shape suitable for each measurement was prepared and evaluated. First, the wear resistance was evaluated by preparing a sample having a length of 120 mm, a width of 120 mm, and a thickness of 2 mm, performing electron beam irradiation in the same manner as the pressing portion 10, and then performing a wear test. A rotary ablation tester (model: TS-2) manufactured by Toyo Seiki Seisakusho Co., Ltd. was used as the testing machine. Set the wear wheel to H-22, the load to 9.8N (4.9N on one side), the rotation speed to 60rpm, and the rotation speed to 1000 rotations, and evaluate the wear resistance in accordance with JIS K 7204. went. In the evaluation of the abrasion test shown in Table 1, when the amount of mass loss after the test was less than 0.025 g, it was evaluated as “◯”, and when the amount of decrease was 0.025 g or more, it was evaluated as “x”.

The compression set was evaluated after preparing a disk-shaped sample having a diameter of 25 mm and a thickness of 6.3 mm and performing the same electron beam irradiation as that of the pressing portion 10. The evaluation of the compression set was performed in accordance with JIS K 6262 at a temperature of 180 ° C., a time of 22 hours, and a compression amount of 25%.
After the compression set, if no cracks or cracks can be confirmed, "◎" is displayed, and if some cracks are observed but no cracks can be confirmed and it is recognized that there is no problem, "○" is displayed. When some cracks were observed but the level was not a problem, it was evaluated as "Δ".

Regarding the oil resistance test, a sample having a length of 35 mm, a width of 52 mm, and a thickness of 2 mm was prepared, and after performing the same electron beam irradiation as the pressing portion 10, it was evaluated under the following conditions. IRM903 was used as the oil. The contact conditions with the oil were a temperature of 150 ° C. and a time of 72 hours. The oil resistance was evaluated by the volume change rate before and after the test, and it was judged that the lower the volume change rate, the less the sample swells due to oil. Specifically, in the evaluation of oil resistance shown in Table 1, "◎" is given when the volume change rate before and after the test is less than 29%, and "○" is given when the volume change rate is 29% or more and less than 38%. And, when the same volume change rate was 38% or more, it was evaluated as "x".

Table 1 shows the evaluation results of each Example and Comparative Example.

It was found that the rubber hardness tended to increase as the electron beam irradiation dose increased. The higher the rubber hardness, the better the sensory evaluation and oil resistance. With regard to wear resistance, almost the same good results were obtained regardless of the irradiation dose of the electron beam. Regarding the compression set, there was no big problem in the range of the electron beam irradiation dose in the range of 100 kGy to 1200 kGy, but 100 kGy to 600 kGy was more preferable, and 100 kGy to 200 kGy was more preferable. Considering the compression set, the rubber hardness of some parts 15 is preferably higher in the range of 31% or more and 122% or less than the rubber hardness of other parts, and is higher in the range of 31% or more and 94% or less. Is more preferable, and higher in the range of 31% or more and 44% or less is even more preferable.

The push button switch member according to the present invention is used in various devices having a press-type key, such as a portable communication device, a personal computer, a camera, an automobile, an in-vehicle electronic device, a home audio device, and a home electric appliance. It can be used to configure a push button switch.

1,2,3,4,5 ... Push button switch member, 1a, 1b ... Element body, 10,10a, 10b, 10c ... Pressing part, 15,15a, 15b ... Partial Locations, 20, 20a, 20b, 20c ... thin-walled movable parts, 30 ... base parts, e ... electron beams.

Claims (10)

It includes a pressing portion, a thin-walled movable portion connected to the outer periphery of the pressing portion, and a base portion connected to the outer periphery of the thin-walled movable portion, and the pressing portion projects to one side with reference to the base portion. , at least the pressing portion and the thin movable part, made of the same kind of rubber-like elastic material, seen including at least a portion of the top surface of the pressing portion does not reach from the top surface to the bottom surface toward its lower predetermined A method for manufacturing a push button switch member, wherein the rubber hardness of the upper region up to the depth of is higher than the rubber hardness of the lower region located below the upper region .
A forming step of forming at least the pressing portion and the thin-walled movable portion with the rubber-like elastic body to form a base body of the push button switch member.
An irradiation step of irradiating the upper region of the pressing portion of the element body with an electron beam to make the upper region harder than the lower region .
A method for manufacturing a member for a push button switch including. The method for manufacturing a push button switch member according to claim 1, wherein in the irradiation step, the irradiation dose of the electron beam is 100 kGy or more. The method for manufacturing a push button switch member according to claim 2, wherein in the irradiation step, the irradiation dose of the electron beam is set to an irradiation dose in the range of 100 kGy to 1200 kGy. The method for manufacturing a push button switch member according to claim 3, wherein in the irradiation step, the irradiation dose of the electron beam is set to an irradiation dose in the range of 100 kGy to 600 kGy. The rubber-like elastic body shall contain silicone rubber.
The method for manufacturing a push button switch member according to any one of claims 1 to 4, wherein the forming step is a step of heating and cross-linking the element body containing a silicone rubber containing a cross-linking agent. The rubber-like elastic body shall contain silicone rubber.
The method for manufacturing a push button switch member according to any one of claims 1 to 4, wherein the forming step is a step of irradiating the element body containing a silicone rubber containing no cross-linking agent with an electron beam to cross-link. Pressing part and
A thin movable portion connected to the outer circumference of the pressing portion and
The base portion connected to the outer circumference of the thin-walled movable portion and
With
The pressing portion projects to one side with respect to the base portion.
At least the pressing portion and the thin-walled movable portion are made of the same type of rubber-like elastic body.
The rubber hardness of the upper region , which includes at least a part of the top surface of the pressing portion and does not reach the bottom surface downward from the top surface , is the rubber hardness of the lower region located below the upper region. Higher push button switch member. The push button switch member according to claim 7, wherein the rubber hardness of the upper region of the pressing portion is 30% or more higher than the rubber hardness of the lower region . The push button switch member according to claim 7 or 8 , wherein the rubber-like elastic body contains silicone rubber. The base portion is provided with a plurality of the thin-walled movable portions, and the pressing portion is provided above each thin-walled movable portion, and the rubber hardness of the upper region in the one or the plurality of the pressing portions is the other one or the plurality of said. The push button switch member according to any one of claims 7 to 9 , which is higher than the rubber hardness of the upper region of the pressing portion.