JP2012003945A - Water proofed push button switch member - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a water proofed push button switch member especially with excellent waterproofness and an excellent switch pushing operation feeling.SOLUTION: A water proofed push button switch member 1 comprises a first elastic member 2 including one or more loop-like ribs 21 continuously formed along an outer circumference of each tubular part 2a in communication with one or more tubular parts 2a opened in two opposite directions and a flange part 2b extending outward in a radial direction from one opening of the tubular part 2a; a tubular reinforcing member 30 opened in both opening directions of the tubular part 2a and fixed inside the first elastic member 2; and a second elastic member 40 opened on the flange part 2b of the first elastic member 2, having a bottom on a side opposite to the flange part 2a and fixed inside the reinforcing member 30. The first elastic member 2 is made of an elastic body with hardness of 60 or less measured by Type A durometer (JIS K6253), and the second elastic member 40 is made of an elastic body with hardness of 70 or more measured by Type A durometer (JIS K6253).

Description

  The present invention relates to a waterproof push button switch member provided in a device having a waterproof function.

  Recently, there is an increasing demand for highly waterproof electronic devices (for example, mobile phones). Most of the water inlets are gaps between the push button and the housing. As a waterproof structure for preventing water from entering the gap, for example, a structure of a waterproof push button switch member in which an elastic body is interposed between a push button and a switch on a circuit board inside the device is known (patent) Reference 1).

  The waterproof structure disclosed in Patent Document 1 includes a cup member made of an elastic material attached to a through-hole so that the opening side faces the outside of the device, and a push button including a shaft portion inserted into the opening of the cup member. And a cylindrical holder made of resin or metal is mounted inside the cup member. Due to the presence of the cylindrical holder, the shape of the cup member can be maintained and the adhesion between the through hole and the cup member can be maintained.

JP 2006-344528

  However, the conventional waterproof structure as described above has the following problems to be solved. Said cup member is comprised from the elastomer represented by silicone rubber, in order to improve adhesiveness with the through-hole of a case. In order to improve the adhesion, it is preferable to use an elastomer having a relatively low hardness. On the other hand, the cup member is also a constituent member that pushes the dome switch, and if it is made of a low-hardness elastomer, the operational feeling of the switch becomes worse. In order to improve the operational feeling of the switch, it is preferable to form the cup member with a high-hardness elastomer, but the adhesiveness with the through-hole is inferior and the waterproof property is lowered. In order to improve the operational feeling of the switch while maintaining waterproofness, a method of reducing the thickness of the bottom surface portion of the cup member is also conceivable, but by repeatedly pressing, the bottom surface portion of the cup member is easily broken, The problem is that the product life is shortened.

  The present invention has been made to solve such a problem, and an object of the present invention is to provide a waterproof pushbutton switch member which is excellent in both waterproofness and a feeling of pressing operation of a switch.

  The present inventor can improve both waterproofness and press operation feeling by configuring the part to be waterproofed with a low-hardness elastomer and forming the part that enhances the press operation feeling with a high-hardness elastomer. As a result, the inventors have found out that the present invention can be achieved. Specific forms of the waterproof push button switch member are as follows.

  In an embodiment of the present invention, one or two or more cylindrical portions that open in opposite directions are connected to a flange portion that extends radially outward from one opening of the cylindrical portion. A first elastic member comprising one or more loop-shaped ribs continuously formed along the outer periphery of each cylindrical part, and the first elastic member that opens in the opening direction of both the cylindrical parts. A cylindrical reinforcing member fixed to the inside of the member; a second elastic member that opens to the flange portion side of the first elastic member and has a bottom on the opposite side of the flange portion and is fixed to the inside of the reinforcing member; The first elastic member is composed of an elastic body having a hardness measured by a type A durometer (JIS K6253) of 60 or less, and the second elastic member has a hardness measured by a type A durometer (JIS K6253). More than 70 elasticity This is a waterproof pushbutton switch member composed of a body.

  Another embodiment of the present invention is a waterproof pushbutton switch member in which the first elastic member and the second elastic member are both made of silicone rubber.

  Another embodiment of the present invention is a waterproof pushbutton switch in which both the outer side surface and the inner side surface of the reinforcing member are respectively subjected to a primer treatment for enhancing the adhesion to the first elastic member and the second elastic member. It is a member.

  Another embodiment of the present invention is a waterproof pushbutton switch member that includes a plunger protruding in a direction away from the bottom on either the outer side or the inner side of the bottom of the second elastic member.

  Another embodiment of the present invention is a waterproof pushbutton switch member further comprising a pushbutton inserted and disposed in a space formed inside the second elastic member from the opening of the second elastic member toward the bottom. .

  ADVANTAGE OF THE INVENTION According to this invention, both the waterproofness of an electronic device provided with a pushbutton switch member and the press operation feeling of a pushbutton switch can be improved.

FIG. 1 is a perspective view of a waterproof pushbutton switch member according to an embodiment of the present invention. FIG. 2 is an exploded perspective view of the waterproof pushbutton switch member shown in FIG. FIG. 3 is a plan view of the main part of the waterproof pushbutton switch member shown in FIG. FIG. 4 is a bottom view of the waterproof pushbutton switch member shown in FIG. FIG. 5 is an assembly cross-sectional view showing a state in which the waterproof pushbutton switch member shown in FIG. 1 is incorporated in the device, and shows only a portion indicated by B in the cross-sectional view along the line AA in FIG. 6 is a cross-sectional view showing a state assembled from the state shown in FIG. FIG. 7 is a cross-sectional view showing the vicinity of the cylindrical portion of the waterproof pushbutton switch member shown in FIG. FIG. 8 is a sectional view showing a manufacturing process of the waterproof pushbutton switch member shown in FIG. 7 and showing a state in which the reinforcing member and the second elastic member are integrally formed. FIG. 9 is a cross-sectional view showing a molded body taken out from the mold after the integral molding step shown in FIG. FIG. 10 is a cross-sectional view showing a state in which the molded body shown in FIG. 9 is arranged in a mold and the first elastic member and the molded body are integrally molded. FIG. 11 is a cross-sectional view showing a first modification of the waterproof pushbutton switch member. FIG. 12 is a cross-sectional view showing a second modification of the waterproof pushbutton switch member. FIG. 13 is a diagram for explaining a click rate evaluation method.

  Next, an embodiment of the waterproof pushbutton switch member of the present invention will be described with reference to the drawings.

<1. Structure of waterproof push button switch member>
FIG. 1 is a perspective view of a waterproof pushbutton switch member according to an embodiment of the present invention. FIG. 2 is an exploded perspective view of the waterproof pushbutton switch member shown in FIG. FIG. 3 is a plan view of the main part of the waterproof pushbutton switch member shown in FIG. FIG. 4 is a bottom view of the waterproof pushbutton switch member shown in FIG.

  The waterproof pushbutton switch member 1 according to this embodiment is made of an elastic material, and is made of three cylindrical portions 2a that open in opposite directions (up and down in FIG. 1) and an elastic material. And a flange portion 2b formed by extending from one opening (lower opening in FIG. 1) of the tubular portion 2a to the radially outer side of the tubular portion 2a. 2 is provided. The preferred thickness (T), width (W), and length (L) of the flange portion 2b are 0.2 to 1.5 mm, 3.0 to 10.0 mm, and 7.0 to 60.0 mm, respectively. is there. The three cylindrical portions 2a are arranged on a substantially straight line on the elongated flange portion 2b. The cylindrical portion 2a is continuously formed along the outer periphery of the cylindrical portion 2a in the middle from the coupling portion with the flange portion 2b to the tip portion of the cylindrical portion 2a, and protrudes outward in the radial direction of the cylindrical portion 2a. Loop-shaped rib 21 is provided. The flange portion 2b includes one through hole 4 in the vicinity of both ends thereof. The through-hole 4 is used, for example, for fixing the waterproof pushbutton switch member 1 to a housing or the like of the device. The first elastic member 2 is made of an elastic material such as a thermoplastic elastomer or a thermosetting elastomer, and preferably made of silicone rubber.

  As shown in FIG. 2, the waterproof pushbutton switch member 1 includes a cylindrical reinforcing member 30 that opens in both opening directions of the respective cylindrical portions 2a and is fixed to the inside of each cylindrical portion 2a. Both opening end faces of each reinforcing member 30 are exposed on both opening sides of the cylindrical portion 2a. Reinforcing member 30 is a metal such as stainless steel, aluminum, aluminum alloy, iron; resin such as polypropylene (PP), polyethylene terephthalate (PET), polycarbonate (PC); ceramics such as alumina, silicon nitride, zirconia; suitable from graphite Configured. However, the material of the reinforcing member 30 is not limited thereto, and any material may be used as long as the material has higher hardness than the first elastic member 2 and the second elastic member 40 described later.

  A second elastic member 40 having a bottom is fixed to the inside of each reinforcing member 30 while opening to the flange portion 2b side of the first elastic member 2 and on the opposite side to the flange portion 2b. Each second elastic member 40 includes one plunger 42 that protrudes outwardly with a smaller diameter than the bottom, outside the bottom. The second elastic member 40 is made of an elastic material such as a thermoplastic elastomer or a thermosetting elastomer, preferably made of silicone rubber, and made of a material having a higher hardness than that of the first elastic member 2. Each hardness of the first elastic member 2 and the second elastic member 40 will be described in detail later.

  A bag-shaped space 7 is formed inside the second elastic member 40, and the waterproof pushbutton switch member 1 can be inserted and installed in each space 7 formed inside the second elastic member 40. 13 is provided. The push button 13 includes a shaft 15 that is inserted into the space 7, and a flange portion 14 that is formed at one end of the shaft 15 and has a larger area than the opening surface of the space 7. The flange portion 14 preferably has a step in the thickness direction, and the upper step has a smaller area than the lower step. The push button 13 is not particularly limited to a material, and is formed of, for example, resin, metal, ceramics, glass, or the like. The push button 13 can also be formed of the same material as that of the reinforcing member 30.

  The waterproof pushbutton switch member 1 includes the first elastic member 2, the reinforcing member 30, and the second elastic member 40 as minimum constituent members, and can further include a pushbutton 13. For this reason, even the structure in which the push button 13 is not provided is referred to as the waterproof push button switch member 1.

  FIG. 5 is an assembly cross-sectional view showing a state in which the waterproof pushbutton switch member shown in FIG. 1 is incorporated in the device, and shows only a portion indicated by B in the cross-sectional view along the line AA in FIG. 6 is a cross-sectional view showing a state assembled from the state shown in FIG. FIG. 7 is a cross-sectional view showing the vicinity of the cylindrical portion of the waterproof pushbutton switch member shown in FIG.

  A casing 50 of a device (for example, a device including a push button represented by a mobile phone, a mobile terminal, a television, a radio, an audio device, etc.) has a through hole 51 into which the cylindrical portion 2a of the first elastic member 2 can be inserted. Have The device includes a dome-shaped switch 60 at the position of the through hole 51 inside the housing 50. The dome-shaped switch 60 is electrically connected to the ring-shaped electrode plate 62 on the printed circuit board (PCB) 61, the electrode plate 63 disposed inside the electrode plate 62, and the electrode plate 62. A conductive dome 64 that is not electrically connected to the electrode plate 63 is provided, and is fixed on the fixing member 65. The dome 64 is elastically deformed by receiving pressure from the cylindrical portion 2 a side and comes into contact with the electrode plate 63. As a result, the electrode plate 62 and the electrode plate 63 are electrically connected. The dome 64 may be made of only a conductive material (metal or the like), or may be made of a non-conductive material and coated with a conductive material on its inner surface. Further, the electrode plate 62 may have a shape other than the ring shape, and the number thereof may be two or more instead of one. A protrusion made of resin or metal that can come into contact with the plunger 42 may be formed on the top of the dome 64.

  The reinforcing member 30 is fixed in a state where the reinforcing member 30 is inserted inside the cylindrical portion 2 a, and the second elastic member 40 is fixed in a state where it is inserted inside the reinforcing member 30. The fixing method may be any method such as adhesion using an adhesive, welding by heating, fitting, clamping, etc., but in order to ensure waterproofness, it is fixed by adhesion using an adhesive. preferable. When the adhesive is used, the primer layer 31 is provided on the outer side surface 30a and the inner side surface 30b of the reinforcing member 30 so as to be firmly bonded to the cylindrical portion 2a of the first elastic member 2 and the second elastic member 40, respectively. Preferably formed. As a material (primer) of the primer layer 31, alkyd resin, modified alkyd resin such as phenol modified / silicone modified, oil-free alkyd resin, acrylic resin, silicone resin, epoxy resin, fluorine resin, phenol resin, polyamide resin, urethane Examples thereof include resins and mixtures thereof. If desired, a crosslinking agent for curing and / or crosslinking the resin can be used. Examples of such a crosslinking agent include isocyanate compounds, melamine compounds, epoxy compounds, peroxides, phenol compounds, and hydrogen siloxane compounds. Etc. A suitable thickness of the primer layer 31 is about 0.1 to 10 μm. Further, when a resin is used for the reinforcing member 30, it is obtained by oxidizing plasma treatment, UV treatment, silicon tetrachloride gas, etc. with an oxidization flame in addition to blasting to roughen the surface of the resin instead of applying a primer. Silicon oxide may be applied to the surface of the reinforcing member 30 to perform surface treatment such as so-called itro treatment for forming a silicon oxide film.

  When the reinforcing member 30 is made of a metal cylinder, the outer side surface 30a and the inner side surface 30b of the reinforcing member 30 are covered with the first elastic member 2 and the second elastic member 40, respectively. Can be achieved. In particular, when the first elastic member 2 and the second elastic member 40 are made of silicone rubber, the corrosion resistance of the reinforcing member 30 is further increased due to the water repellency of silicone.

  The rib 21 continuously formed along the outer periphery of the tubular portion 2 a is deformed by being compressed from the inner wall of the through hole 51 in a state where the tubular portion 2 a is pushed into the through hole 51 of the housing 50 and incorporated. Thereby, a high waterproof function can be realized. Moreover, the rib 21 is formed in the cylindrical part 2a in the position and magnitude | size which do not remove | deviate from the through-hole 51 of the housing 50 in the movable range of the cylindrical part 2a.

  The first elastic member 2 is made of an elastic body having a low hardness because it is necessary to maintain a high waterproof property by improving the adhesion with the inner wall of the through hole 51 of the housing 50. Specifically, an elastic body having a hardness measured by a type A durometer (JIS K6253) of 60 or less is used as the first elastic member 2. If the hardness exceeds 60, the deformation amount of the rib 21 is reduced, and a gap is likely to be formed between the inner wall of the through hole 51 and the waterproof property is inferior. On the other hand, if the 1st elastic member 2 is comprised with the said elastic body with the said hardness 60 or less, the rib 21 becomes easy to deform | transform flexibly and can maintain high waterproofness.

  The second elastic member 40 is a member having a role of pressing the dome 64 with a plunger 42 formed on the outer side of the bottom 41 and turning on the dome 64. In order to enhance the pressing feeling, the second elastic member 40 is made of an elastic body having a hardness measured by a type A durometer (JIS K6253) of 70 or more. If the second elastic member 40 is formed of an elastic body having a hardness of less than 70, when the dome 64 is pressed, the amount of deformation in the pressing direction of the second elastic member 40 is too large, and the pressing operation feeling is reduced. On the other hand, when the second elastic member 40 is composed of an elastic body having a hardness of 70 or more, the deformation amount in the pressing direction of the second elastic member 40 is small, and the pressing operation feeling is improved.

  The material of the first elastic member 2 and the second elastic member 40 is not particularly limited. For example, silicone rubber, ethylene-propylene-diene rubber, butadiene rubber, isoprene rubber, chloroprene rubber, natural rubber, acrylonitrile butadiene rubber Styrene butadiene rubber, styrene rubber, butyl rubber, halogenated butyl rubber, polyisobutylene, chlorosulfonated polyethylene rubber, acrylic rubber, urethane rubber, polyether copolymer, epichlorohydrin copolymer, etc. can be used. Even if it uses alone, it can also be used in mixture of 2 or more types. Of the materials exemplified above as the material of the first elastic member 2 and the second elastic member 40, a particularly preferable material is silicone rubber. The hardness of the elastic body can vary depending on the type of uncrosslinked rubber material used, the degree of crosslinking, the amount of filler added, and the like. In order to make the hardness of the second elastic member 40 larger than the hardness of the first elastic member 2, the second elastic member 2, 40 has a second elasticity even when the same uncrosslinked rubber material is used in addition to changing the uncrosslinked rubber material of each elastic member 2, 40. A method of further promoting the crosslinking of the member 40 or increasing the amount of filler added to the second elastic member 40 can be employed.

<2. Manufacturing Method of Waterproof Pushbutton Switch Member>
(1) Primer layer forming step The primer treatment of the reinforcing member 30 is performed prior to molding. The primer layer 31 is formed on the reinforcing member 30 by coating the primer on the outer side surface 30a and the inner side surface 30b of the reinforcing member 30 or by immersing the reinforcing member 30 in a primer solution in a mesh basket. Is preferably performed. After the primer treatment, the formation of the primer layer 31 is completed by drying the reinforcing member 30 for a predetermined time. When the primer layer 31 is formed by the ittro process, a silicon oxide film is formed on the outer side surface 30a and the inner side surface 30b of the reinforcing member 30 by oxidizing silicon tetrachloride gas or the like with an oxidizing flame.

(2) Primary Integrated Molding Step FIG. 8 is a cross-sectional view showing a manufacturing process of the waterproof pushbutton switch member shown in FIG. 7 and showing a state where the reinforcing member and the second elastic member are integrally molded. FIG. 9 is a cross-sectional view showing a molded body taken out from the mold after the integral molding step shown in FIG.

  The reinforcing member 30 after the primer treatment is set in the first mold 70, and an uncrosslinked elastomer composition 90, which is dispensed and processed into a sheet shape after predetermined mixing, is placed inside the reinforcing member 30, and the first Cover the second mold 80. The second mold 80 includes a protrusion 81 for forming the space 7. The first mold 70 includes a recess 71 for forming the plunger 42. By compressing and heating at a desired temperature and pressure for a predetermined time, as shown in FIG. 9, a molded body 100 with the second elastic member 40 fixed inside the reinforcing member 30 is completed.

  Note that the primer layer 31 may be formed again on the outer surface 30a of the reinforcing member 30 after the above-described primary integral molding. Further, the formation of the primer layer 31 is divided into two stages. Before the primary integral molding, the primer layer 31 is formed only on the inner surface 30b of the reinforcing member 30, and after the primary integral molding, the outer surface of the reinforcing member 30 is formed. The primer layer 31 may be formed only on 30a.

(3) Second Integrated Molding Step FIG. 10 is a cross-sectional view showing a state in which the molded body shown in FIG. 9 is arranged in a mold and the first elastic member and the molded body are integrally molded.

  After the first integral molding, the molded body 100 shown in FIG. 9 is set in a third mold 110, and the elastomer composition in an uncrosslinked state is processed into a sheet shape after predetermined mixing on the outside of the reinforcing member 30. The object 130 is put and a fourth mold 120 is put on the object 130. The third mold 110 includes a protrusion 111 for insertion into the space 7. The fourth mold 120 includes a recess 121 for forming the rib 21. By compressing and heating at a desired temperature and pressure for a predetermined time, the waterproof pushbutton switch member 1 in a state in which the first elastic member 2 is integrally formed outside the reinforcing member 30 is completed.

(4) Assembly After the second integral molding step, the push button 13 is inserted into the space 7 in the tubular portion 2a, and the assembly of the waterproof push button switch member 1 is completed.

<3. Modification of Waterproof Pushbutton Switch Member>
FIG. 11 is a cross-sectional view showing a first modification of the waterproof pushbutton switch member. FIG. 12 is a cross-sectional view showing a second modification of the waterproof pushbutton switch member.

  As shown in FIG. 11, the waterproof pushbutton switch member 1 in which the plunger is not formed outside the bottom 41 of the second elastic member 40 can be manufactured. In that case, it is preferable to form a plunger that protrudes toward the bottom 41 at the top of the dome 64 in order to improve the pressing feeling.

  Moreover, as shown in FIG. 12, the waterproof pushbutton switch member 1 in which the plunger 42 and the plunger 43 are respectively formed on both the outside and the inside of the bottom 41 of the second elastic member 40 can be manufactured.

  The waterproof pushbutton switch member according to the present invention is not limited to the above-described embodiment, and can be implemented with various modifications.

  In the above-described embodiment, the reinforcing member 30 has a flange-less sleeve shape. However, the reinforcing member 30 may include a flange portion at the opening portion on the flange portion 2b side. Similarly, the 2nd elastic member 40 may be provided with the flange part in the opening part by the side of the flange part 2b. Moreover, you may form the rib 21 formed in the outer peripheral part of the cylindrical part 2a of the 1st elastic member 2 two or more steps | paragraphs in the length direction of the cylindrical part 2a. The opening end of the cylindrical portion 2a in the dome 64 direction protrudes in the dome 64 direction from the opening end of the reinforcing member 30 in the same direction, or the opening end of the reinforcing member 30 in the dome 64 direction is the same as that of the cylindrical portion 2a. You may make it protrude in the dome 64 direction from the opening end of a direction.

  In the integral molding of the reinforcing member 30 and the first elastic member 2 or the second elastic member 40, the method for charging the uncrosslinked rubber material into the mold is performed by compression molding, injection molding, transfer molding, extrusion molding, or the like. Can do.

  Next, an embodiment of the waterproof push button switch member of the present invention will be described.

<1. Manufacture of waterproof pushbutton switch member>
A primer (product of Shin-Etsu Chemical Co., Ltd.) is formed on the outer side surface 30a and the inner side surface 30b of the cylindrical reinforcing member 30 (inner diameter: 2.65 mm, outer diameter: 2.95 mm, length: 1.55 mm) made of SUS304. Name: Primer No. 23) was applied, air-dried for 30 minutes, and subjected to a heat treatment at 100 ° C. for 60 minutes in a dryer to form a primer layer 31 on the reinforcing member 30.

Next, the 1st metal mold | die 70 and the 2nd metal mold | die 80 which are shown in FIG. 8 are prepared, the above-mentioned reinforcement member 30 with the primer layer 31 is set to the 1st metal mold | die 70, Shin-Etsu Chemical Co., Ltd. A silicone rubber compound (trade name: KE-981U) made of 100 parts by weight of a cross-linking agent (trade name: C-8) manufactured by Shin-Etsu Chemical Co., Ltd. was kneaded and separated into a sheet. Silicone rubber A was put inside the reinforcing member 30, and the second mold 80 was put over and the mold was clamped. Thereafter, the first mold 70 and the second mold 80 were heated at 170 ° C. for 5 minutes under a pressure of 180 kg / cm ² . Next, after sufficiently cooling, the first mold 70 and the second mold 80 are opened, and the molded body 100 in which the second elastic member 40 and the reinforcing member 30 are integrated (see FIG. 9). Was taken out. The second elastic member 40 had an inner diameter of 2.55 mm, an outer diameter of 2.65 mm, a base thickness of 0.3 mm, a presser length: 0.6 mm, and a presser diameter: 0.2 mm.

Next, the 3rd metal mold | die 110 and the 4th metal mold | die 120 which are shown in FIG. 10 are prepared, the molded object 100 is set to the 3rd metal mold | die 110, and the silicone rubber compound (product of Shin-Etsu Chemical Co., Ltd.) Name: KE-931U) 100 parts by weight of a cross-linking agent (trade name: C-8) manufactured by Shin-Etsu Chemical Co., Ltd. is kneaded with 2 parts by weight of uncrosslinked silicone rubber B which is separated into a sheet, and reinforcing member 30 The mold was put on the outside and the fourth mold 120 was put on and clamped. Then, the 3rd metal mold | die 110 and the 4th metal mold | die 120 were heated for 5 minutes at 170 degreeC under 180 kg / cm < ² > pressurization. Next, after sufficiently cooling, the third mold 110 and the fourth mold 120 are opened, and a molded body in which the first elastic member 2, the reinforcing member 30, and the second elastic member 40 are integrated. I took it out. The cylindrical portion 2a of the first elastic member 2 has an inner diameter of 2.95 mm and an outer diameter of 3.45 mm at a portion other than the rib 21, and an outer diameter of 3.25 mm at the most protruding portion of the rib 21. The shape was 85 mm.

  In the waterproof pushbutton switch member 1 manufactured by the above manufacturing process, the second elastic member 40 having a hardness of 80 according to the type A durometer (JIS K6253) is fixed inside the reinforcing member 30 and the type A outside the reinforcing member 30 is fixed. The first elastic member 2 having a durometer (JIS K6253) hardness of 30 is fixed. In addition, another five types of silicone rubber compounds (trade names: KE-931U, KE-941U, KE-951U, KE-961U manufactured by Shin-Etsu Chemical Co., Ltd.) are used as silicone rubber compounds of the uncrosslinked silicone rubber A. , KE-971U), and five other types of silicone rubber compounds (trade names: KE-941U, KE-951U, KE- manufactured by Shin-Etsu Chemical Co., Ltd.) as the silicone rubber compound of the uncrosslinked silicone rubber B 961U, KE-971U, KE-981U). As a result, a total of 36 types of waterproof pushbutton switch members 1 were prepared by combining the first elastic member 2 and the second elastic member 40 each using six types of silicone rubber compounds.

<2. Characteristic evaluation>
Each waterproof pushbutton switch member 1 was subjected to the following evaluation of waterproofness and pressing operability.

(1) Evaluation method of waterproof property The waterproof property of each waterproof pushbutton switch member 1 was evaluated by a differential pressure method using an air circuit. In this method, determination is made based on the pressure difference between the tank in which the test item is stored and the reference tank, and both tanks are connected by the same circuit. In the apparatus, the test article was put into a jig having a predetermined shape and pressurized, and the test was accepted when the differential pressure in the circuit after a lapse of a certain time was within 1 kPa.

(2) Evaluation method of pressing operability Using a feeling tester (product number: MODEL1013) manufactured by Ikko Engineering Co., Ltd., a substantially cylindrical shaft having a lower surface diameter of 1.8 mm or more and an upper surface diameter of 2.2 mm or less is used. The push button 13 is mounted in the space 7 of the second elastic member 40, and the degree of pressing operation feeling was evaluated based on the click rate (%) when the pressing operation was performed. The click rate is the maximum load (F1) immediately before the dome 64 is dented when the push button 13 is pushed in the stroke-load curve shown in FIG. The minimum load (F2) is a value calculated by 100 × (F1−F2) / F1. The larger the numerical value of the click rate, the better the feeling of pressing operation. The click rate when the dome 64 portion of the dome-shaped switch 60 was directly pressed by the push button 13 was 39%. Therefore, when pressing through the second elastic member 40, the ideal pressing feeling is close to 39%.

<3. Evaluation results>
Table 1 shows the results of characteristic evaluation of 36 types of waterproof pushbutton switch members manufactured by combining 6 types of silicone rubber compounds.

  As shown in Table 1, when the hardness of the first elastic member 2 is 60 or less, good waterproof properties can be maintained, whereas when the hardness exceeds 60, the waterproof properties are lowered. Further, when the hardness of the second elastic member 40 is 70 or more, the click rate is 30% or more, and a good pressing feeling is obtained. On the other hand, when the hardness is less than 70, the click rate is 20% or less, and the pressing operation is good. The feeling was not obtained. From the above, the hardness of the first elastic member 2 fixed to the outside of the reinforcing member 30 is made of a low-hardness elastic material having a hardness of 60 or less, and the hardness of the second elastic member 40 fixed to the inside of the reinforcing member 30 is 70. It was found that both the waterproof property and the feeling of pressing operation can be improved by using the above-described high-hardness elastic material.

  The present invention can be used as a push button switch member incorporated in a waterproof device.

DESCRIPTION OF SYMBOLS 1 Waterproof pushbutton switch member 2 1st elastic member 2a Tubular part 2b Flange part 7 Space 13 Pushbutton 21 Rib 30 Reinforcement member 30a Outer side surface 30b Inner side surface 31 Primer layer 40 Second elastic member 41 Bottom part 42 Plunger 43 Plunger

Claims (5)

One or two or more cylindrical parts that open in opposite directions and a flange part that extends from one opening part of the cylindrical part to the outside in the radial direction are connected to each other. A first elastic member comprising one or more loop-shaped ribs continuously formed along the outer periphery of the cylindrical portion;
A cylindrical reinforcing member that opens in both opening directions of the cylindrical portion and is fixed inside the first elastic member;
A second elastic member that opens to the flange portion side of the first elastic member and has a bottom on the opposite side of the flange portion, and is fixed to the inside of the reinforcing member;
With
The first elastic member is composed of an elastic body having a hardness measured by a type A durometer (JIS K6253) of 60 or less,
The waterproof pushbutton switch member, wherein the second elastic member is made of an elastic body having a hardness measured by a type A durometer (JIS K6253) of 70 or more.   The waterproof pushbutton switch member according to claim 1, wherein both the first elastic member and the second elastic member are made of silicone rubber.   The primer treatment for improving the adhesiveness with said 1st elastic member and said 2nd elastic member is respectively made | formed on both the outer surface and the inner surface of the said reinforcement member, respectively. Item 3. A waterproof push button switch member according to Item 2.   The waterproof pushbutton switch according to any one of claims 1 to 3, further comprising a plunger that protrudes in a direction away from the bottom portion on either the outer side or the inner side of the bottom portion of the second elastic member. Element.   5. The push button inserted and disposed in a space formed inside the second elastic member from the opening of the second elastic member toward the bottom thereof, further comprising: The waterproof push button switch member according to claim 1.

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