JP2017054691A - Push switch, and manufacturing method of push switch - Google Patents

Abstract

PROBLEM TO BE SOLVED: To maintain a desired pressing operation feeling in a push switch even after heat treatment.SOLUTION: A case 2 comprises a recess 21. A first stationary conductive member 3 and a second stationary conductive member 4 are disposed within the recess 21. A movable electrode 5 is disposed within the recess 21 and elastically deformable between a first state where the first stationary conductive member 3 and the second stationary conductive member 4 are electrically insulated and a second state where the first and second stationary conductive members are electrically conducted. A first resin cover 6 has first flexibility and covers the recess 21. A second resin cover 7 has second flexibility that is lower than the first flexibility, and is fixed to the first resin cover 6 so as to oppose the movable electrode 5. A pressing member 8 is disposed between the first resin cover 6 and the second resin cover 7 and configured to elastically deform the movable electrode 5 via the second resin cover 7 in response to deformation of the first resin cover 6.SELECTED DRAWING: Figure 3

Description

  The present invention relates to a push switch mounted on an electronic device or the like. The present invention also relates to a method of manufacturing a push switch mounted on an electronic device or the like.

  The push switch described in Patent Document 1 includes a case having a recess. A plurality of fixed electrodes and movable electrodes are arranged in the recess. The movable electrode is elastically deformable between a state in which a plurality of fixed electrodes are electrically connected to each other and a state in which they are insulated. When no load is applied, the plurality of fixed electrodes are insulated. The recess is covered with a resin (nylon or PPS) cover. A pressing member is disposed between the cover and the movable electrode. When a pressing force is applied from the outside, the pressing member deforms the movable electrode in the recess. As a result, the plurality of fixed electrodes are conducted.

JP 2013-058380 A

  In the push switch described in Patent Document 1, a resin cover is laser welded to the case. As a result, even if the contact area between the cover and the case is reduced with the downsizing of the push switch, the fixing strength of the cover to the case can be secured.

  However, the inventor of the present application has found a decrease in mechanical characteristics in the push switch having the above-described configuration. FIG. 4A shows the relationship between the operation amount of the push switch (the displacement amount of the pressing member) and the operation force. A broken line indicates a characteristic when the push switch is assembled. A one-dot chain line indicates a characteristic after the push switch is mounted on a circuit board mounted on the electronic device. The solid line shows the characteristics after the annealing process for applying a thermal load.

  As a general tendency of the characteristic curve after the operation is started, first, the operating force increases as the displacement amount of the pressing member increases. This tendency corresponds to a phenomenon in which the elastic resistance of the movable electrode increases as the pressing member is displaced to deform the movable electrode. When the displacement amount of the pressing member reaches a certain value, the operating force is rapidly reduced. This tendency corresponds to a phenomenon in which the movable electrode is deformed to realize a click feeling and receives an operating force.

  From the result shown in FIG. 4A, it can be seen that the rising edge of stage A moves to the right as the push switch undergoes heat treatment. This fact means that the force for displacing the pressing member is not efficiently transmitted to the movable electrode. In addition, although not shown in the drawings, it was confirmed that the operating force does not decrease smoothly when the operating force rapidly decreases. From these results, it can be seen that the originally intended behavior of the push switch, that is, the desired pressing feeling is not stably maintained.

  It is an object of the present invention to maintain a desired pressing feeling in a push switch even after heat treatment.

In order to achieve the above object, a first aspect of the present invention is a push switch,
A case having a recess;
A plurality of fixed electrodes disposed in the recess;
A movable electrode disposed in the recess and elastically deformable between a first state electrically insulating the plurality of fixed electrodes and a second state electrically conductive;
A first resin cover having first flexibility and covering the recess;
A second resin cover having a second flexibility lower than the first flexibility, and being fixed to the first resin cover so as to face the movable electrode;
It is arranged between the first resin cover and the second resin cover, and is configured to elastically deform the movable electrode via the second resin cover according to the deformation of the first resin cover. A pressing member,
It has.

In order to achieve the above object, a second aspect of the present invention is a method of manufacturing a push switch,
Prepare a case where a plurality of fixed electrodes are arranged in the recess,
A movable electrode is disposed in the recess so as to be elastically deformable between a first state that electrically insulates the plurality of fixed electrodes and a second state that is electrically conductive.
Fixing the pressing member to the first resin cover having the first flexibility;
A second resin cover having a second flexibility lower than the first flexibility is fixed to the first resin cover so as to cover the pressing member,
The first resin cover to which the pressing member and the second resin cover are fixed is fixed to the case so as to cover the recess.

  According to the above configuration, an appropriate tension is applied to the first resin cover by the second resin cover, and deformation of the first resin cover due to the thermal load can be suppressed. Therefore, the desired operational feeling of the push switch can be maintained even after the heat treatment.

  Moreover, since the pressing member is arrange | positioned between the 1st resin cover and the 2nd resin cover, it can prevent that a pressing member peels from a 1st resin cover by the load added repeatedly through pressing operation. Since the positional relationship between the pressing member and the movable electrode is stably maintained, the desired operational feeling of the push switch can be maintained even after repeated use over a long period.

The push switch according to the first aspect can be configured as follows.
The first resin cover is made of nylon or PPS (polyphenylene sulfide).

  Nylon and PPS are materials with high laser transparency. Therefore, laser welding can be used to fix the first resin cover to the case. In this case, even if the push switch is small, not only the positioning of the first resin cover can be performed with high accuracy, but also the fixing strength to the case against a load repeatedly applied can be increased. Therefore, it is possible to further improve the stability of the pressing operation feeling while responding to the strict demand for miniaturization of the push switch.

  Therefore, the manufacturing method according to the second aspect can be configured as follows.

  The pressing member and the second resin cover are fixed to the first resin cover by laser welding.

The push switch according to the first aspect can be configured as follows.
The maximum width dimension of the case in the direction intersecting the displacement direction of the pressing member is 2.5 mm or less.

  According to said structure, the pressing operation feeling of a push switch can be maintained stably also to such a severe request | requirement of size reduction.

The manufacturing method according to the second aspect may be configured as follows.
After the first resin cover is fixed to the case, an annealing process is performed.

  According to said structure, even if it passes through the process supposing the thermal load in a mounting environment, the press operation feeling of a push switch can be maintained stably.

  According to the present invention, it is possible to maintain a desired pressing feeling in the push switch even after heat treatment.

It is a disassembled perspective view which shows the push switch which concerns on one Embodiment. It is a four-plane figure which shows the external appearance of the push switch of FIG. It is sectional drawing which shows the internal structure of the push switch of FIG. It is a figure which shows the mechanical characteristic of the push switch of FIG.

  Exemplary embodiments according to the present invention will be described below in detail with reference to the accompanying drawings. In each drawing used in the following description, the scale is appropriately changed to make each member a recognizable size. The expressions “front and rear”, “left and right” and “up and down” are used for convenience of explanation, and do not limit the posture and direction in the actual use state.

  FIG. 1 is an exploded perspective view showing a configuration of a push switch 1 according to an embodiment. FIG. 2 is a four-side view showing the appearance of the assembled push switch 1. FIG. 2A is a top view. FIG. 2B is a front view. FIG. 2C is a bottom view. FIG. 2D is a right side view. Since the shape seen from the left side is symmetrical to that shown in the right side view, the illustration is omitted. Since the shape seen from the back is symmetrical to that shown in the front view, the illustration is omitted. FIG. 3 shows a cross section viewed from the arrow direction along line III-III in FIG.

  As shown in FIG. 1, the push switch 1 includes a case 2. The case 2 is made of an insulating material such as resin. The case 2 has a recess 21.

  As shown in FIG. 1 and FIG. 2C, the push switch 1 includes a pair of first fixed conductive members 3. Each first fixed conductive member 3 is made of a conductive material such as copper. Each first fixed conductive member 3 is fixed integrally with the case 2 by insert molding or the like. The first portion 31 of each first fixed conductive member 3 is disposed in the recess 21 of the case 2 and functions as a fixed electrode. The second portion 32 of the first fixed conductive member 3 is exposed on the side surface of the case 2 and functions as an external terminal.

  As shown in FIG. 1 and FIG. 2C, the push switch 1 includes a second fixed conductive member 4. The second fixed conductive member 4 is made of a conductive material such as copper. The second fixed conductive member 4 is fixed integrally with the case 2 by insert molding or the like. The first portion 41 of the second fixed conductive member 4 is disposed in the recess 21 of the case 2 and functions as a fixed electrode. The second portion 42 of the second fixed conductive member 4 is exposed on the side surface of the case 2 and functions as an external terminal.

  As shown in FIG. 1, the push switch 1 includes a movable electrode 5. The movable electrode 5 is made of a conductive material such as copper. The movable electrode 5 has a dome-like appearance having a central part 51 and a peripheral part 52. As shown in FIG. 3, the movable electrode 5 is disposed in the recess 21 of the case 2. The central portion 51 of the movable electrode 5 is disposed so as to face the first portion 41 of the second fixed conductive member 4 with a space therebetween. The peripheral edge 52 of the movable electrode 5 is in contact with the first portion 31 of each first fixed conductive member 3. As will be described later, the central portion 51 of the movable electrode 5 is elastically deformable in the direction indicated by the arrow D1 in FIG.

  As shown in FIG. 1, the push switch 1 includes a first resin cover 6. The first resin cover 6 has flexibility. The first resin cover 6 has a central part 61 and a peripheral part 62. As shown in FIG. 3, the first resin cover 6 is fixed to the case 2 so as to cover the recess 21. Specifically, the peripheral edge portion 62 is fixed to the upper surface 22 of the case 2 so that the central portion 61 faces the concave portion 21.

  As shown in FIG. 1, the push switch 1 includes a second resin cover 7. The second resin cover 7 is made of a material having flexibility (second flexibility) lower than the flexibility (first flexibility) of the first resin cover 6. An example of the material is a polyimide film on which an acrylic adhesive surface is formed. As shown in FIG. 3, the second resin cover 7 is fixed to the first resin cover 6 via the adhesive surface so as to face the movable electrode 5.

  As shown in FIG. 1, the push switch 1 includes a pressing member 8. The pressing member 8 is made of a material having higher rigidity than the first resin cover 6. Examples of the material include thermoplastic resins such as polyamide resins, thermosetting resins such as epoxy resins, metals, and alloys thereof. As shown in FIG. 3, the pressing member 8 is disposed between the first resin cover 6 and the second resin cover 7.

  As shown in FIG. 2C and FIG. 3, the push switch 1 includes a third resin cover 9. The third resin cover 9 is made of an insulating material having heat resistance. An example of the material is a polyimide film on which an acrylic adhesive surface is formed. The first fixed conductive member 3 and the second fixed conductive member 4 are protected by bonding the bonding surface to the bottom surface 23 of the case 2.

  In the unloaded state shown in FIG. 3, the central portion 51 of the movable electrode 5 and the first portion 41 of the second fixed conductive member 4 are separated from each other. On the other hand, the first portion 31 of each first fixed conductive member 3 and the first portion 41 of the second fixed conductive member 4 are also spaced apart. Therefore, each first fixed conductive member 3 and second fixed conductive member 4 are electrically insulated (an example of the first state).

  When a load equal to or greater than a certain value is applied to the first resin cover 6 from above, the pressing member 8 causes the central portion of the movable electrode 5 via the second resin cover 7 according to the deformation of the first resin cover 6. 51 is elastically deformed downward. Although illustration is omitted, the central portion 51 of the movable electrode 5 thereby contacts the first portion 41 of the second fixed conductive member 4. Since the movable electrode 5 is made of a conductive material, each first fixed conductive member 3 and the second fixed conductive member 4 are electrically connected (an example of a second state).

  A method of manufacturing the push switch 1 having the above configuration will be described.

  First, the pressing member 8 is fixed to the lower surface of the first resin cover 6 (the surface facing the concave portion 21 of the case 2 when the push switch 1 is completed). The fixing method may be appropriately determined such as adhesion or welding.

  Subsequently, a drawing process is performed in which the first resin cover 6 is pressed against the pressing member 8 from above. Thereby, the center part 61 of the 1st resin cover 6 which has an upward convex shape is formed.

  Next, the second resin cover 7 is bonded to the lower surface of the first resin cover 6 so as to cover the pressing member 8. Accordingly, the pressing member 8 is sandwiched between the first resin cover 6 and the second resin cover 7.

  On the other hand, the movable electrode 5 is disposed in the recess 21 of the case 2 in which the third resin cover 9 is bonded to the bottom surface 23. Thereafter, the peripheral edge 62 of the first resin cover 6 in a state where the second resin cover 7 and the pressing member 8 are fixed is fixed to the upper surface 22 of the case 2. Thereby, the push switch 1 which has the structure mentioned above is obtained.

  The inventor of the present application has found that the change in the mechanical characteristics of the push switch described with reference to FIG. 4A is caused by the material of the cover covering the concave portion of the case. In the push switch, laser welding is used to fix the cover. For laser welding, nylon or PPS (polyphenylene sulfide), which has a high laser transmission property, is selected. However, it has been found that these materials are deformed by a thermal load applied through a soldering process or an annealing process, and acquire a spring property. As a result, it was found that the mechanical characteristics of the originally intended push switch changed. Furthermore, it was found that the method of changing the characteristics becomes unexpectedly unstable because the method of deformation due to heat load is not uniform.

  As a result of repeated studies, the inventor of the present application attaches a second cover having a lower flexibility than the first cover that covers the concave portion of the case to the first cover, thereby providing an appropriate tension for the first cover. I got the idea that the deformation due to heat load could be suppressed. Furthermore, by covering the pressing member fixed to the first cover with the second cover, it may be possible to prevent the pressing member from being peeled off from the first cover by a load repeatedly applied through the pressing operation. I got the idea.

  Based on this idea, in the push switch 1 according to the present embodiment, the second resin cover having lower flexibility than the first resin cover 6 so as to cover the pressing member 8 fixed to the first resin cover 6. 7 is provided. The pressing member 8 is sandwiched between the first resin cover 6 and the second resin cover 7.

  With respect to the push switch 1 configured as described above, changes in mechanical characteristics were examined under the same conditions as those shown in FIG. The result is shown in FIG. It can be seen that the mechanical characteristics of the push switch 1 are stably maintained even when a thermal load is applied. When the state of the first resin cover 6 after the annealing treatment was examined, no deformation due to heat load was confirmed.

  That is, in the push switch 1 according to the present embodiment, the second resin cover 7 having lower flexibility than the first resin cover 6 that covers the recess 21 of the case 2 is attached to the first resin cover 6. . Thereby, moderate tension | tensile_strength is given to the 1st resin cover 6, and the deformation | transformation of the 1st resin cover 6 resulting from a heat load can be suppressed. Therefore, the desired operational feeling in the push switch 1 can be maintained even after the heat treatment.

  Further, since the pressing member 8 is disposed between the first resin cover 6 and the second resin cover 7, it is possible to prevent the pressing member 8 from being peeled from the first resin cover 6 due to a load repeatedly applied through the pressing operation. Since the positional relationship between the pressing member 8 and the movable electrode 5 is stably maintained, a desired operational feeling in the push switch 1 can be maintained even after a long period of repeated use.

  In the present embodiment, nylon or PPS is used as the material of the first resin cover 6.

  Nylon and PPS are materials with high laser transparency. Therefore, laser welding can be used to fix the first resin cover 6 to the case 2. In this case, even if the push switch 1 is small, not only the positioning of the first resin cover 6 can be performed with high accuracy, but also the strength of fixing the case 2 to a load that is repeatedly applied can be increased. Therefore, it is possible to further improve the stability of the pressing operation feeling while responding to the strict demand for downsizing of the push switch 1.

  In the present embodiment, the maximum width dimension of the case 2 in the direction (the direction indicated by the arrow D2 in FIG. 3) intersecting the deformation direction of the movable electrode 5 (the direction indicated by the arrow D1 in FIG. 3) is 2.5 mm. It is as follows. According to the above-described configuration, the pressing operation feeling of the push switch 1 can be stably maintained even in response to such a strict demand for downsizing.

  In the present embodiment, after the push switch 1 is assembled, an annealing process is performed assuming a thermal load in the mounting environment. According to the above-described configuration, the pressing operation feeling of the push switch 1 can be stably maintained even through such heat treatment.

  The above embodiment is merely an example for facilitating understanding of the present invention. The configuration according to the above embodiment can be changed or improved as appropriate without departing from the spirit of the present invention. In addition, it is obvious that equivalents are included in the technical scope of the present invention.

  1: push switch, 2: case, 21: recess, 3: first fixed conductive member, 4: second fixed conductive member, 5: movable electrode, 6: first resin cover, 7: second resin cover, 8: Press member, D1: direction of displacement of movable electrode, D2: direction intersecting with direction of displacement of movable electrode

Claims (6)

A case having a recess;
A plurality of fixed electrodes disposed in the recess;
A movable electrode disposed in the recess and elastically deformable between a first state electrically insulating the plurality of fixed electrodes and a second state electrically conductive;
A first resin cover having first flexibility and covering the recess;
A second resin cover having a second flexibility lower than the first flexibility, and being fixed to the first resin cover so as to face the movable electrode;
It is arranged between the first resin cover and the second resin cover, and is configured to elastically deform the movable electrode via the second resin cover according to the deformation of the first resin cover. A pressing member,
With
Push switch. The first resin cover is made of nylon or PPS.
The push switch according to claim 1. The maximum width dimension of the case in a direction intersecting the displacement direction of the pressing member is 2.5 mm or less.
The push switch according to claim 1 or 2. A method of manufacturing a push switch,
Prepare a case where a plurality of fixed electrodes are arranged in the recess,
A movable electrode is disposed in the recess so as to be elastically deformable between a first state that electrically insulates the plurality of fixed electrodes and a second state that is electrically conductive.
Fixing the pressing member to the first resin cover having the first flexibility;
A second resin cover having a second flexibility lower than the first flexibility is fixed to the first resin cover so as to cover the pressing member,
Fixing the first resin cover to which the pressing member and the second resin cover are fixed to the case so as to cover the recess;
Production method. The pressing member and the second resin cover are fixed to the first resin cover by laser welding.
The manufacturing method according to claim 4. Annealing is performed after the first resin cover is fixed to the case.
The manufacturing method of Claim 4 or 5.

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