JP5228901B2 - Push-on switch - Google Patents

Description

  The present invention relates to a push-on switch that is used in an operation unit of various electronic devices, is mounted with an operation unit protruding from an end of a wiring board, and is pressed from a direction parallel to the surface of the wiring board.

  In recent years, along with the thinning of various electronic devices, there are an increasing number of electronic devices in which operation buttons are also arranged on the side surfaces. The operation buttons can be pressed from a direction parallel to the mounted wiring board surface. A push-on switch suitable for thinning is used. On the other hand, static electricity charged on the human body during the pressing operation flows from the operation button to the signal circuit via the push-on switch, which may cause malfunction or failure of electronic devices. Yes.

  Such a conventional push-on switch will be described with reference to FIGS.

  8 is an external view of a conventional push-on switch, FIG. 9 is a sectional view thereof, FIG. 10 is an exploded perspective view thereof, FIG. 11 is a plan view of the switch case, FIG. 12 is a sectional view of the same operation state, and FIG. It is an external view of a mounting state. For the convenience of explanation, the external view and the exploded perspective view are viewed from obliquely rearward.

  In the figure, reference numeral 1 denotes a switch case made of a substantially rectangular insulating resin having a corner protrusion 1B having an L-shape when viewed from above at four corners on the upper surface and having a recess 1A at the center of the upper surface. The center fixed contact 2 and the outer fixed contact 3 are exposed at two points in the left-right direction of the point target position centered on the center fixed contact 2 at the center of the inner bottom surface of 1A. Then, as shown in FIG. 11, the central contact terminals 4 are led out one by one from the rear side of the left and right side walls connected to the central fixed contact 2, and connected to the outer side fixed contact 3 to the front part of the left and right side walls. The outer contact terminals 5 are led out one by one from the side to the outside. That is, the center contact terminal 4 and the outer contact terminal 5 are one set each, and one set is led out from the left and right side walls of the switch case 1. Each of the terminals 4 and 5 is extended in a planar shape substantially the same as the lower surface of the switch case 1 in a direction perpendicular to the side wall.

  Reference numeral 6 denotes a movable contact made of an elastic metal thin plate having an upward convex circular dome shape. The lower end of the outer periphery is placed on the two outer fixed contacts 3 and is accommodated in the recess 1A of the switch case 1. Yes.

  Reference numeral 7 denotes a protective sheet made of a flexible insulating film, which has an adhesive layer (not shown) on its lower surface, and is mounted on the upper surface of the switch case 1 by the adhesive layer so as to cover the concave portion 1A, and the movable contact 6 is recessed. It is housed and held in 1A.

  Reference numeral 8 denotes an operating body in which an operating portion 8A protrudes forward from the switch case 1, and a driving portion 8B having a bar-like pressing portion 8C having a spherical tip is protruded behind the operating portion 8A. Further, a frame portion 8D is provided so as to surround the drive portion 8B, and this frame portion 8D is placed on the protective sheet 7 adhered to the upper surface of the switch case 1.

  9 has an inclined portion 9B which is bent so that the front end side is inclined downwardly downward toward the center position of the flat plate portion 9A, and a ground leg portion 9C is extended downward at the central portion of the rear end. A cover made of a thin metal plate, with the pressing portion 8C at the tip of the driving portion 8B of the operating body 8 in contact with the front surface of the inclined portion 9B, the locking portions 9D provided at the four corner portions are switch cases. 1 is fixed to the outer surface of the corner projection 1B. The lower end position of the ground leg 9C is set to be substantially the same position as the lower surface position of the switch case 1.

  The operating body 8 is in contact with the protective sheet 7 adhered to the upper surface of the switch case 1 at both sides of the frame 8D and the flat plate portion 9A of the cover 9 so that the upper and lower surfaces are in sliding contact with the corner projection 1B of the switch case 1. It can be moved back and forth within the enclosed range.

  As described above, the conventional push-on switch is configured, and the operation thereof will be described.

  First, when the operation portion 8A of the operation body 8 is pushed from the front toward the rear, the operation body 8 moves rearward, and the pressing portion 8C at the distal end of the drive portion 8B follows the inclined portion 9B of the cover 9 along with the movement. To move diagonally downward. Then, when the pressing portion 8C presses the dome-shaped apex portion of the movable contact 6 through the protective sheet 7 and exceeds a predetermined pressing force, the movable contact 6 is elastically inverted, as shown in FIG. The lower surface of the dome-shaped apex portion contacts the center fixed contact 2, and the outer fixed contact 3 and the center fixed contact 2 are electrically connected.

  When the pushing operation applied to the operation portion 8A is stopped, the dome-shaped portion of the movable contact 6 self-resets to the original upward convex shape and is separated from the central fixed contact 2, and the outer fixed contact 3 and the central fixed contact 2 Is in an insulated state. Due to the restoring force of the movable contact 6, an upward biasing force acts on the pressing portion 8 </ b> C of the operating body 8 via the protective sheet 7, and the pressing portion 8 </ b> C moves obliquely upward along the inclined portion 9 </ b> B of the cover 9. With the movement of the pressing portion 8C, the operating body 8 is returned to the original front position shown in FIG.

  Next, the mounting state of this push-on switch will be described with reference to FIG.

  Reference numeral 10 denotes a wiring board provided with soldering lands 11 on the upper surface near the end thereof. The lands 11 include two outer contact terminal lands 11A, two central contact terminal lands 11B, and one ground leg. A set of land 11C is provided.

  Corresponding outer contact terminals 5, center contact terminals 4, and ground leg portions 9C are soldered to the lands 11 (11A, 11B, 11C) of the wiring board 10, and push-on switches are mounted.

  When static electricity charged on the human body flows into the operation part 8A of the push-on switch through the fingertip or the like in this mounted state, the static electricity is transmitted to the cover 9 made of a metal plate located above the operation part 8A, and is grounded. The circuit is configured to flow from a leg portion 9C to a ground circuit (not shown) connected to the ground leg portion land 11C, so that malfunction of the mounted electronic device does not occur.

As prior art document information related to the invention of this application, for example, Patent Document 1 and Patent Document 2 are known.
JP 2002-343178 A Japanese Patent Laid-Open No. 11-39987

  However, in the conventional push-on switch, static electricity from a human body or the like to be operated is transmitted from the operation portion 8A to the cover 9, and flows from the ground leg portion 9C of the cover 9 to the grounding circuit of the wiring board 10. The operation part 8A may flow to the outer contact terminal 5 led to the front side of the switch case 1, and static electricity flows to the signal circuit connected to the outer contact terminal 5, thereby causing malfunction or failure of the mounted electronic device. Since there is a possibility of the occurrence, there has been a demand for improvement of static electricity flowing into the outer contact terminal 5 located on the front side of the switch case 1.

  The present invention solves such a conventional problem, and provides a push-on switch configured to protect against static electricity flowing into a terminal located on the front side of a switch case close to an operation unit. With the goal.

  In order to achieve the above object, the present invention has the following configuration.

Invention of Claim 1 of this invention has a switch case provided with a pair of fixed contacts in a crevice, and an operation object arranged so that an operation part may protrude from the front of the above-mentioned switch case, A push-on switch in which the pair of fixed contacts are brought into and out of contact with each other by being pressed in a direction parallel to the wiring board in a mounted state in which terminals are mounted on the wiring board, and the switch on / off state is switched. The terminals include two contact terminals from the switch case that are electrically connected to the pair of fixed contacts, respectively, and a ground terminal from the switch case that is electrically independent of the pair of fixed contacts. The ground terminal is provided on the front side of the switch case as compared to the two contact terminals, and the switch on / off state is switched off. Despite is obtained by a push-on switch, characterized in that where the structure obtained between the ground terminal above two, which is positioned behind the contact terminals, are located on the front side of the switch case, close to the operating unit By making the terminal a ground terminal that is electrically independent from the fixed contact for the switch, even if static electricity flows into the terminal (ground terminal) located on the front side via the operation section, problems such as malfunction or failure of electronic devices occur. This has the effect that a push-on switch can be provided.

  According to a second aspect of the present invention, there is provided a wiring board according to the first aspect, wherein a metal cover is attached to the switch case, and a leg portion extends from the cover in the vicinity of the grounding terminal. The above-mentioned legs are soldered to a land integrally formed with the grounding terminal land, and the grounding land on the cover side can be shared with the grounding terminal land and flow to the cover. The static electricity can be surely passed through the grounding circuit against the static electricity, and the cover leg is soldered at a position close to the switch operation side, so the soldered part is peeled off by the pressing load applied to the operation part. It has the effect of providing a material that is strong against strength.

  As described above, according to the present invention, it is possible to provide a push-on switch configured to reliably flow static electricity flowing into a terminal located on the front side near the operation unit to the grounding circuit. Is obtained.

  Hereinafter, embodiments of the present invention will be described with reference to FIGS. In addition, the same code | symbol is attached | subjected to the part of the structure same as the structure demonstrated in the term of the prior art, and detailed description is simplified.

(Embodiment)
FIG. 1 is a cross-sectional view of a push-on switch according to an embodiment of the present invention, FIG. 2 is an exploded perspective view thereof, FIG. 3 is a plan view of the switch case, and FIG. For convenience of explanation, the external view and the exploded perspective view are as seen from obliquely rearward as in the conventional case.

  In the figure, reference numeral 21 denotes a switch case made of an insulating resin having a substantially rectangular recess 21A on the upper surface and having a substantially rectangular shape when viewed from the upper surface, and a corner protrusion 21B protruding upward in an L shape toward the four corner portions of the upper surface. And a cylindrical center fixed contact 22 and a prismatic outer fixed contact 23 are exposed on the inner bottom surface of the recess 21A.

  As shown in FIG. 3, the center fixed contact 22 is positioned at the center of the inner bottom surface of the substantially circular recess 21 </ b> A, and the outer fixed contact 23 is disposed away from the center fixed contact 22 and on the left peripheral edge of the recess 21 </ b> A. In addition, a rectangular column-shaped receiving portion 21 </ b> C of insulating resin having the same size as the outer fixed contact 23 is provided on the right peripheral portion at a position symmetrical to the outer fixed contact 23 with respect to the central fixed contact 22. Then, the central contact terminal 24 is led out from the rear part of the right side wall of the switch case 21 in connection with the central fixed contact 22, and the outer contact terminal 25 is led out from the rear part of the left side wall of the switch case 21 in connection with the outer fixed contact 23. Yes.

  In addition, a flat ground terminal 26 that is electrically fixed from the center fixed contact 22 and the outer fixed contact 23 to the switch case 21 by insert molding is led out from the front portions of the left and right side walls one by one. .

  That is, the ground terminal 26 is led out on the front side and the central contact terminal 24 is led out on the rear side of the right side wall of the switch case 21, and the ground terminal 26 is led out on the front side and the outer contact terminal 25 is led out on the rear side of the switch case 21. The lower surfaces of the terminals 24, 25, and 26 are led out in a flat plate shape on the same plane as the lower surface of the switch case 21.

  Reference numeral 6 denotes a movable contact made of an elastic metal thin plate made of a stainless steel plate or the like, which has a circular dome shape that bulges upward and has an outer peripheral lower end placed on the outer fixed contact 23 and the receiving portion 21C. 23 and the movable contact 6 are in a conductive state and are accommodated in the recess 21A of the switch case 21 with the lower surface of the dome-shaped apex facing the central fixed contact 22 and a gap.

  Reference numeral 7 denotes a protective sheet made of an insulating film, which is provided with an adhesive layer (not shown) on the lower surface. The adhesive layer is adhesively fixed to the upper surface of the switch case 21 and covers the recess 21A.

  Reference numeral 8 denotes an operating body made of an insulating resin. An operating portion 8A that protrudes forward of the switch case 21 and an elastic rod-shaped pressing portion 8C that protrudes rearward from the center of the rear surface of the operating portion 8A. It is formed in a shape having a drive unit 8B and a frame portion 8D provided so as to surround the drive unit 8B with a space from the drive unit 8B from both ends of the rear surface of the operation unit 8A. The frame portion 8D is placed on the upper surface of the protective sheet 7. The operating body 8 is configured such that the frame portion 8D is movable in the front-rear direction within a range surrounded by the corner projection 21B by restricting the movement in the left-right direction by the corner projection 21B of the switch case 21.

  Reference numeral 9 denotes a cover made of a metal plate having a slanted portion 9B formed at the center of the flat plate portion 9A and bent so that the front end side is inclined downward and downward, and is placed on the upper surface of the corner projection 21B of the switch case 21. The engaging portions 9D provided at the four corner portions of the flat plate portion 9A are arranged outside the corner projection portion 21B of the switch case 21 with the pressing portion 8C at the tip of the driving portion 8B in contact with the front surface of the inclined portion 9B. Locked to the wall and fixed. In addition, a ground leg 9C bent downward is provided at the center of the rear end.

  Since the switch operation of the push-on switch configured as described above is the same as the conventional one, description thereof is omitted.

  Next, the mounting state of this push-on switch will be described with reference to the external view of the mounting state of FIG.

  As shown in FIG. 4, the push-on switch is soldered and mounted on a wiring board 30 of an electronic device (not shown) having a push-on switch mounting land 31 on the upper surface. The land 31 is provided with five corresponding to the four terminals 24, 25, 26 led out from the switch case 21 of the push-on switch and the ground leg 9 C of the cover 9.

  Specifically, a ground terminal land 31C is provided at a position corresponding to the ground terminal 26 on the front side of the left and right side walls of the switch case 21, and the outer contact terminal is positioned at a position corresponding to the outer contact terminal 25 led out to the rear side of the left side wall. The land 31A is provided, the center contact terminal land 31B is provided at a position corresponding to the center contact terminal 24 led out on the rear side of the right side wall, and the cover 9 is grounded at a position corresponding to the ground leg 9C. A leg land 31D is provided.

  The ground terminal 26, the outer contact terminal 25, the central contact terminal 24, and the ground leg 9C are respectively connected to the ground terminal land 31C, the outer contact terminal land 31A, the central contact terminal land 31B, and the ground leg land 31D. Is soldered and the push-on switch is mounted on the wiring board 30. The ground terminal land 31C and the ground leg land 31D are connected to a ground circuit (not shown).

  As described above, according to the present embodiment, when static electricity from the human body or the like flows into the operation unit 8A and is transmitted to the cover 9 side, the ground leg 9C connected to the ground leg land 31D is grounded. The ground terminal 26 is electrically independent from the fixed contacts 22 and 23 in the switch case 21 even if static electricity flows into the ground terminal 26 located near the operation portion 8A. Since it is not connected to the circuit, the push-on switch can be provided which can be surely passed through the grounding circuit via the grounding terminal land 31C and does not cause problems such as malfunction or failure of the electronic device. As described above, the ground terminal 26 led out from the left and right has a configuration in which a single flat plate member connected between them is embedded in the switch case 21 to form the switch case 21. Although it is possible to prevent generation of unnecessary warping including the time and soldering, and it is preferable to make it excellent in strength, the left and right ground terminals 26 may be fixed as individual members.

  Moreover, it is good also as a structure as shown in the external view explaining the mounting by the form of another cover of FIG.

  5 differs from that shown in FIGS. 1 to 4 in that the ground leg portion 49C provided on the flat plate portion 49A of the cover 49 is positioned at the position of the ground terminal 46 led out to the front side of the left and right side walls of the switch case 41. In addition, the flat plate portion 49 </ b> A extends downward from the front side end portion, and is bent and soldered so that the front end portion thereof is parallel to the upper surface of the wiring substrate 32. The ground terminal 46 from the switch case 41 is set to a length that does not hinder the ground leg portion 49C having the above-described configuration.

  In the case of the push-on switch configured as described above, the ground terminal 46 led out from the switch case 41 and the ground leg portion 49C of the cover 49 can be shared and soldered by the same ground terminal land 32C. Even if static electricity flows through the cover 49 or through the ground terminal 46, it can be surely passed through the grounding circuit, and the ground leg land 31D of the wiring board 30 shown in FIG. 4 is unnecessary. Thus, circuit pattern design is easy and design flexibility can be improved. Furthermore, since the ground leg 49C is also soldered at a position close to the operation side, it is possible to provide a push-on switch that is strong against the peeling strength of the soldering portion due to the pressing load applied to the operation portion 8A.

  Moreover, it is good also as a structure as shown in the external view explaining the mounting by the form of another cover of FIG.

  The configuration shown in FIG. 6 eliminates the bending of the tip of the ground leg 59C of the cover 59 as compared with the configuration of FIG. 5, and the tip extending vertically downward as it is is provided in the land 33C for the ground terminal of the wiring board 33. The through hole 33D is soldered and attached.

  With this configuration, the same ground terminal land 33C is used for the ground terminal 46 and the ground leg portion 59C for both static electricity flowing to the cover 59 side and static electricity flowing to the ground terminal 46 side. In addition, the push-on switch can be provided which is stronger against the peeling strength of the soldering portion due to the pressing load applied to the operation portion 8A of the push-on switch.

  Furthermore, it is good also as a structure as shown in the external view explaining the mounting by the form of another cover of FIG.

  In the configuration shown in FIG. 7, the shape portion for inserting the through hole shown in FIG. 6 is provided at the tip of the ground terminal 56 from the switch case 51. That is, the ground leg 49C of the cover 49 has the shape shown in FIG. 5, and the tip of the ground terminal 56 led out from the switch case 51 is bent downward and perpendicular to the surface of the wiring board 34. The shape of the wiring board 34 that is soldered and attached to a through hole 34D provided in the ground terminal land 34C is different from the above-described shape.

  With this configuration, as in the case shown in FIG. 6, the ground terminal land 34 </ b> C can be integrally formed and shared for the ground terminal 56 and the ground leg 49 </ b> C of the cover 49, and push-on can be performed. It is possible to provide a push-on switch that is strong in the peeling strength of the soldering portion due to the pressing load applied to the switch operation portion 8A.

  Note that the terminals and ground legs described above are not limited to those formed in a planar shape in substantially the same plane as the lower surface of the corresponding switch case, but other terminal shapes of surface mount type, for example, It may be in the form of a J vent terminal. In addition, the detailed configuration of the contact portion of the switch and the operation body is not limited to the above-described one.

  The push-on switch according to the present invention has an advantageous effect that the static electricity flowing into the terminal located on the front side near the operation unit can be surely passed through the grounding circuit, and is useful for the operation unit of various electronic devices. .

Sectional drawing of the push-on switch by one embodiment of this invention Exploded perspective view Top view of the switch case External view of the same mounting state External view explaining mounting in the form of another cover External view explaining mounting in the form of another cover External view explaining mounting in the form of another cover External view of conventional push-on switch Cross section Exploded perspective view Top view of the switch case Sectional view in the same operating state External view of the mounted state

Explanation of symbols

6 movable contact 7 protective sheet 8 operation body 8A operation portion 8B drive portion 8C pressing portion 8D frame portion 9, 49, 59 cover 9A, 49A flat plate portion 9B inclined portion 9C, 49C, 59C ground leg portion 9D locking portion 21, 41 , 51 Switch case 21A Recess 21B Corner protrusion 21C Receiving part 22 Center fixed contact 23 Outer fixed contact 24 Center contact terminal 25 Outer contact terminal 26, 46, 56 Earth terminal 30, 32, 33, 34 Wiring board 31 Land 31A Outer contact Land for terminal 31B Land for central contact terminal 31C, 32C, 33C, 34C Land for ground terminal 31D Land for ground leg 33D, 34D Through hole

Claims (2)

In a mounted state having a switch case provided with a pair of fixed contacts in the recess, and an operation body arranged so that the operation part protrudes from the front of the switch case, the terminal is mounted on the wiring board. A push-on switch in which the pair of fixed contacts are brought into contact with and separated from each other by a pressing operation in a direction parallel to the wiring board, and the switch on / off state is switched, and the terminals are electrically connected to the pair of fixed contacts, respectively. Two contact terminals from the switch case connected to each other and a ground terminal from the switch case that is electrically independent of the pair of fixed contacts. It is provided on the front side of the switch case compared to two contact terminals, and the switching of the switch on / off state is behind the ground terminal. Push switch, characterized in that it has a structure obtained between location has been the two contact terminals. A metal cover is attached to the switch case, a leg is extended from the cover in the vicinity of the ground terminal, and the leg is soldered to a land integrally formed with the land for the ground terminal of the wiring board to be mounted. The push-on switch according to claim 1, wherein the push-on switch is used.

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