JP2005332664A - Diaphragm for key switch, and its manufacturing method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a diaphragm for key switch having a plurality of leg parts provided around the center part with a spacing in which cracks are not brought about even if pushing operations are repeated. <P>SOLUTION: The diaphragm 1 for the key switch is manufactured by a metal sheet having elasticity and is provided with a center part 3 curved in dome shape and a plurality of leg parts 5 provided around the center part 3 in the periphery direction with a spacing mutually. Cut-out pieces 7 of the bridge portion still remain at the peripheral part of the leg parts 55. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a diaphragm for a key switch and a manufacturing method thereof.

  Conventionally, as shown in the plan view and the cross-sectional view of FIGS. 5A and 5B, the key switch diaphragm 100 is formed from a sheet metal having elasticity and curved in a dome shape. A plurality of legs 104 are provided around 102 and spaced apart from each other in the circumferential direction.

  This diaphragm is used, for example, as a push switch installed on a circuit board. In this case, for example, when the central portion 102 is pressed via a key top or the like on the circuit board (arrow A in FIG. 5B), the diaphragm is elastically deformed, and the contacts provided on the circuit board are connected to each other. It is electrically connected through the diaphragm.

    The key switch diaphragm 100 is conventionally manufactured through a manufacturing process shown in FIG. 6, for example.

  More specifically, first, a thin metal plate 106 is sequentially pressed or molded using a mold, for example, to leave a band-shaped bridge portion 108 between the sheet metal remaining material (or sheet metal frame material) 106. A large number of diaphragms 100 are formed.

  Thereafter, by cutting the bridge portion 108, the diaphragm 100 and the sheet metal residue 106 are separated, and each diaphragm 100 is obtained.

As a method of forming a key switch diaphragm by pressing a thin plate or the like, for example, a method described in Non-Patent Document 1 is known.
Fujikura Technical Review No. 104, April 2003, p43

  However, in the above manufacturing method, as shown in FIG. 5, the cut piece 110 of the bridge portion 108 usually remains between the two leg portions 104 of the diaphragm 100 after the bridge portion 108 is cut.

  The diaphragm 100 has a problem that the crack 112 shown in FIG. 5 is generated from the periphery of the cut piece 110 of the bridge portion 108 while the pressing operation is repeated.

  The present invention has been made in view of the above problems, and in a diaphragm for a key switch having a plurality of legs provided at intervals around a central portion, the pressing operation can be repeated. An object of the present invention is to provide a diaphragm for a key switch which does not generate a crack.

  As a result of intensive studies on the cause of the crack, the present inventors have found that the crack 112 occurs due to stress concentration between the legs 104 when the diaphragm 100 is pushed in.

  Furthermore, it has been found that the stress concentration is further increased by the presence of the cut piece 110.

  Accordingly, the diaphragm for a key switch according to the present invention is manufactured from a sheet metal having elasticity, and has a central portion curved in a dome shape and a plurality of legs provided around the central portion and spaced apart from each other in the circumferential direction. And a cutting piece of the bridge portion remains on the peripheral edge portion of the leg portion.

  The diaphragm has, for example, a bridge piece at the tip of the leg.

  The diaphragm has, for example, a bridge piece at the side edge of the leg.

  The diaphragm manufacturing method for a key switch according to the present invention is a method for manufacturing a diaphragm having a dome-shaped central portion and a plurality of legs provided around the central portion. By cutting the sheet metal having elasticity along the outer shape, cutting the sheet metal leaving the bridge portion between the diaphragm and the sheet metal remaining material, and cutting the bridge portion, Separating the diaphragm from the sheet metal remaining material, and in the step of cutting the sheet metal, the bridge portion is formed between a peripheral portion of the leg portion and the sheet metal remaining material. .

  In the method, it is preferable that the bridge portion is formed between a tip end of the leg portion and a sheet metal remaining material.

  The diaphragm for a key switch according to the present invention is less likely to crack even when used repeatedly.

  FIG. 1 is a perspective view showing a schematic configuration of a key switch diaphragm 1 manufactured according to an embodiment of the present invention, and FIG. 2 is a cross-sectional view showing a IIA-IIB cross section in FIG.

  This key switch diaphragm (hereinafter sometimes simply referred to as “diaphragm”) 1 is used, for example, as a push button switch of an electronic device.

  This key switch diaphragm 1 is formed by pressing a thin plate-like body (a flat plate-like body having a thickness of, for example, 60 to 90 μm) made of a metal member such as stainless steel or phosphor bronze. A center portion 3 obtained by molding and curved in a dome shape and a plurality of leg portions 5 provided around the center portion 3 (in the circumferential direction) at intervals from each other are provided.

  As shown in the drawing, each leg 5 projects radially from the center 3 in four directions.

  In addition, when the diaphragm 1 is formed from the plate-like body, the diaphragm 1 and a portion other than the diaphragm 1 are connected to each other at the distal ends of the pair of opposing legs 5 of the legs 5. The connected piece 7 of the bridge portion remains.

  More details are as follows.

  First, the center part 3 curved in the dome shape will be described.

  As shown in FIG. 2, the central portion 3 curved in a dome shape has a spherical shell-shaped central dome shape portion 9 having a radius of curvature R1 of about 35 to 40 mm and a central dome shape portion 9. It is formed by a donut-shaped peripheral dome-shaped portion 11 provided integrally with the central dome-shaped portion 9. As shown in the drawing, the cross section of the peripheral dome-shaped portion 11 has the shape of the side surface of the truncated cone.

  The upper side (inner diameter side) of the peripheral dome-shaped portion 11 is connected to the outer periphery of the central dome-shaped portion 9.

  An inner diameter d1 of the peripheral dome-shaped portion 11 is, for example, about 4 to 5 mm, and an outer diameter d3 of the peripheral dome-shaped portion 11 is, for example, about 6 to 7 mm.

  Further, the generatrix of the peripheral dome-shaped portion 11 (a line segment extending from the apex of the cone formed by extending the side surface of the truncated cone of the peripheral dome-shaped portion 11 to the bottom surface of the cone along the side surface of the cone) The intersection angle θ1 between 11A and the horizontal plane h1 including the inner diameter portion of the peripheral dome-shaped portion 11 is, for example, 10 to 15 °.

  Next, each leg 5 will be described.

  As shown in FIG. 1, the diaphragm 1 is formed in a “ten” shape by four legs 5.

  Each leg portion 5 has a base end portion 13 provided integrally with the peripheral dome shape portion 11 and a tip end portion 15 provided integrally with the base end portion 13 around the peripheral dome shape portion 11.

  The side edge portion 13A of each base end portion 13 is formed to have an arc shape 17 (see FIG. 1) when the diaphragm 1 is viewed from above.

  As shown in FIG. 1, the central portion 17 </ b> A of the arc length of the arc shape 17 is in contact with the peripheral dome-shaped portion 11.

  Further, the radius R3 of the circular arc 17 is designed to be larger than that of a conventional diaphragm in order to avoid pressure concentration during pressing, and is, for example, about half of the outer diameter d7 of the tip portion 15.

  By selecting the radius R3 in this way, it is possible to reduce the stress concentration when the switch is pressed and to obtain a good click feeling.

  As shown in FIGS. 1 and 2, the upper side of the base end portion 13 is connected to the outer periphery of the lower side of the peripheral dome-shaped portion 11, and the lower side of the base end portion 13 is connected to the peripheral dome-shaped portion. The direction extends away from the outer periphery of the portion 11 and extends obliquely downward in FIG.

  Moreover, the intersection angle θ3 between the bus bar 13A of the base end portion 13 and the horizontal surface h3 including the outer diameter portion on the lower side of the peripheral dome-shaped portion 11 is, for example, 15 to 20 °.

  Furthermore, the outer diameter d5 of the circumscribed circle on the lower side of the base end portion 13 is, for example, 8 to 9 mm.

  As shown in FIG. 2, the inner side of the distal end portion 15 is connected to the outer periphery of the proximal end portion 13, and the outer side of the distal end portion 15 extends from the outer periphery of the proximal end portion 13 in the outer horizontal direction. Yes.

  The outer diameter d7 of the circumscribed circle of the tip 15 is about 10 mm, for example.

  As shown in FIG. 1, the bridge piece 7 described above remains at the tip of each of the four leg portions 5 of the four leg portions 5 facing each other.

    Next, the function and effect of the diaphragm 1 will be described.

  As already described, the diaphragm 1 is used for a push button switch installed on a circuit board, for example. Therefore, a case where the diaphragm is pressed by a switch operation will be described.

  The diaphragm 1 is placed on the circuit board so that the tip of the leg part 5 is in contact with a flat circuit board (not shown) and the central part 3 is separated from the circuit board. The diaphragm 1 is installed on the circuit board using a diaphragm support sheet or the like.

  Then, the central portion 3 of the diaphragm 1 is pressed in a direction indicated by an arrow AR1 shown in FIG. 1 through a key top (not shown) or the like.

  By the pressing, the diaphragm 1 is elastically deformed, the central portion 3 is in contact with the circuit board, and the contacts provided on the circuit board are electrically connected to each other.

  When the key switch diaphragm 1 is pressed, stress is applied to the diaphragm 1, and the applied stress is concentrated in the central portion 17 </ b> A of the arc shape 17 or in the vicinity thereof, as in the conventional diaphragm 100.

  However, according to the diaphragm 1 for a key switch of the present invention, since the cut piece 7 of the bridge portion 23 is provided at the distal end portion 15 of the leg portion 5, the stress is applied to the arc-shaped central portion 17A as described above. Even if the concentration occurs, further stress concentration due to the cut piece 7 does not occur, and generation of cracks can be avoided.

  According to the experiment, in the diaphragm 1 of this embodiment, no crack was generated even by the pressing operation of 1 million times or more.

  Next, a manufacturing method of the diaphragm 1 will be described with reference to FIG.

  First, as shown in FIG. 3, the diaphragm 1 is formed from a thin metal plate 19 having elasticity by pressing or molding.

  At this time, a bridge portion 23 that connects between the diaphragm 1 and a sheet metal remaining material (or sheet metal frame material) 21 other than the diaphragm 1 is left.

  Thereby, many diaphragm 1 is formed in the state which is easy to handle.

  The bridge portion 23 is formed in, for example, a narrow rectangular shape, and one end portion thereof is connected to the distal end portion 15 of the leg portion 5 of the diaphragm 1 and the other end portion thereof is connected to the sheet metal remaining material 21. It is connected.

    Subsequently, the bridge portion 23 is cut in the vicinity of the leg portion 5 of the diaphragm 1, and the diaphragm 1 is separated from the sheet metal remaining material 21.

  By cutting the bridge portion 23, as shown in FIG. 1, a cut piece 7 of the bridge portion 23 that protrudes slightly from the distal end portion 15 is formed at the distal end portion 15 of the leg portion 5 of the diaphragm 1.

  According to this manufacturing method, as described above, for example, it is possible to manufacture a diaphragm that does not crack with respect to a pressing operation of 1 million times or more, and since the bridge portion 23 is provided at the distal end portion 15 of the leg portion, The bridge portion 23 can be efficiently removed using a large cutting cutter.

  The present invention is not limited to the above embodiment, and can be implemented in other forms based on the technical idea of the present invention.

  FIG. 4 is a plan view of another embodiment of the diaphragm 1 for a key switch. As shown in the drawing, in this diaphragm, a cut piece 7 a of a bridge portion is formed on a side edge portion of the leg portion 5.

  Moreover, in the diaphragm 1 for key switches, you may provide the protrusion which protruded below in the bottom face of a pair of leg part front-end | tip part 15 which each said leg part 5 opposes.

  By providing such a projection, when the diaphragm is installed on a flat circuit board, the diaphragm has three points (the two projections and the tip portion 15 of one leg portion 15 having no projection). Point), it comes into contact with the circuit board, and the backlash of the diaphragm can be suppressed, and the click feeling can be improved.

  Further, if the two protrusions are provided on the leg portion 5 having the cut piece 7, even if the cut piece 7 slightly protrudes downward from the leg portion 5, the influence of this protrusion can be avoided. That is, when the diaphragm 1 is installed on the circuit board, the cut piece 7 can be prevented from coming into contact with the circuit board, and rattling of the diaphragm 1 can be avoided.

  The key switch diaphragm 1 may be configured such that the distal end portion 15 having a slight size located on the outermost side is deleted, and the outer diameter of the proximal end portion 13 is 10 mm. .

It is a figure which shows schematic structure of the diaphragm for key switches which concerns on embodiment of this invention. It is a figure which shows the IIA-IIB cross section in FIG. It is a figure explaining the case where the diaphragm for key switches is manufactured. It is a top view of other embodiment of the diaphragm for key switches. It is a top view which shows the general view of the diaphragm for the conventional key switch. It is a figure which shows a part of manufacturing process of the diaphragm for the conventional key switch.

Explanation of symbols

1 Diaphragm for key switch 3 Center part 5 Leg part 7 Bridge piece

Claims (5)

A diaphragm for a key switch, which is manufactured from an elastic sheet metal and has a central portion curved in a dome shape and a plurality of legs provided around the central portion and spaced apart from each other in the circumferential direction. There,
A diaphragm for a key switch, wherein a cut piece of a bridge portion remains on a peripheral portion of the leg portion. A diaphragm for a key switch according to claim 1,
The key switch diaphragm, wherein the peripheral edge portion is a tip portion of the leg portion. A diaphragm for a key switch according to claim 1,
The key switch diaphragm, wherein the peripheral edge is a side edge of the leg. A method for manufacturing a key switch diaphragm comprising a dome-shaped central portion and a plurality of legs provided around the central portion,
A step of cutting an elastic sheet metal along the outer shape of the diaphragm to be manufactured, and a process of cutting the sheet metal leaving a bridge between the diaphragm and the remaining sheet metal material,
Cutting the diaphragm from the sheet metal residue by cutting the bridge; and
In the process of cutting the sheet metal, the bridge portion is formed between the peripheral edge portion of the leg portion and the remaining sheet metal material. The diaphragm manufacturing method according to claim 4, wherein the bridge portion is formed between a lower end portion of the leg portion and a sheet metal remaining material.

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