JP4956583B2 - Movable contact member and switch device - Google Patents

Description

  The present invention relates to a movable contact member and a switch device, and more particularly to a movable contact member and a switch device incorporated in a small electronic device such as a mobile phone.

  In general, as a movable contact member used in a switch device, a metal thin plate is processed and formed into a dome shape with a predetermined curvature is known. This movable contact member is reversed by pressing, and is restored by elastic restoring force by removing the pressing. In this case, the operation feeling is adjusted by changing the curvature of the movable contact member, but it is difficult to obtain a desired operation feeling such as operating force and click feeling only by changing the curvature of the movable contact member. It was.

  As a movable contact member that solves this problem, a combination of a dome-like bulge and a skirt that supports the outer peripheral side of the bulge is known (for example, see Patent Document 1). . The movable contact member has a skirt portion that rises inward in the radial direction from the outer peripheral edge portion at a predetermined inclination angle, and a bulging portion that continues to the skirt portion and bulges upward at a predetermined curvature. . In this way, by configuring the movable contact member by combining the bulging portion and the skirt portion, the curvature of the bulging portion, the inclination angle of the skirt portion, and the height can be adjusted to obtain a desired operation feeling. I have to.

Japanese Patent Laid-Open No. 11-67002

  By the way, it is known that a disk-shaped member receiving a concentrated load at the center generates a maximum stress amplitude in the circumferential direction at the outer peripheral edge. Moreover, the movable contact member is formed by punching, and there is a tendency for cracks to be generated on the inner side from the outer peripheral edge portion that becomes the fracture surface during processing.

  The movable contact member described in Patent Document 1 has a structure in which an operating force applied to the movable contact member by a pressing operation is received by the skirt portion, so that a circumferential stress amplitude generated at the outer peripheral edge portion of the skirt portion is large. Therefore, although this movable contact member is easy to adjust the operation feeling, it is easy to cause cracks from the outer peripheral edge of the skirt portion to the inside due to repeated pressing operations, and it cannot be given sufficient life performance. There was a problem.

  The present invention has been made in view of such circumstances, and it is easy to adjust the operation feeling, and the movable contact member that can increase the life by reducing the stress amplitude in the circumferential direction at the outer peripheral edge. And it aims at providing a switch apparatus.

  The movable contact member of the present invention has a bulging portion that bulges in a dome shape and a skirt portion that extends radially outward from the outer peripheral edge portion of the bulging portion, and the skirt portion includes the bulging portion. It is characterized by continuing from the outer peripheral edge of the bulging part so as to substantially coincide with the tangential direction of the tangent extending in the radial direction of the dome at the outer peripheral edge of the protruding part.

  According to this configuration, since the extending directions of the outer peripheral edge portion of the bulging portion and the portion connected to the bulging portion of the skirt portion substantially coincide with each other, the bulging portion and the skirt portion are smoothly connected. Thus, when the movable contact member placed on the installation surface is pressed, the operating force due to the pressure is transmitted from the contact portion with the placement surface in the radial direction and the circumferential direction, and transmitted in the skirt portion. However, since the extension direction of the bulge part and the skirt part are substantially the same, the connection is made along the transmission direction of the actuation force, so that the transmission of the actuation force is blocked by the connection part. Instead, it is transmitted from the skirt to the bulge. Therefore, the operating force applied to the movable contact member is received not only at the skirt portion but also at the bulging portion. Therefore, the stress amplitude in the circumferential direction generated at the outer peripheral edge of the skirt portion by the repeated pressing operation of the movable contact member is reduced, and the life of the movable contact member can be extended. Moreover, since it is formed by the bulging part and the skirt part, the curvature of the bulging part, the boundary position between the skirt part and the bulging part, etc., compared with the movable contact member formed in a dome shape with a predetermined curvature. By adjusting this, it becomes easy to obtain a desired operation feeling. Note that the term “continuous so as to substantially match” is not limited to the case where the tangential direction at the outer peripheral edge of the bulging portion is completely matched, and the operating force is not received only by the skirt portion. It is only necessary to match the tangential direction within such a range, that is, within a range that does not block the transmission of stress from the outside toward the center during the pressing operation.

  In the movable contact member according to the present invention, the skirt portion is linearly formed along a tangential direction of a tangent extending in the radial direction of the dome at the outer peripheral edge of the bulging portion. .

  According to this configuration, it is possible to reduce the circumferential stress amplitude generated in the outer peripheral edge portion of the skirt portion, thereby extending the life, and adjusting the inclination angle of the skirt portion to adjust the operation feeling.

  According to the present invention, in the movable contact member, the skirt portion is formed along a circumscribed circle with respect to a tangent extending in the radial direction of the dome at the outer peripheral edge of the bulged portion.

  According to this configuration, it is possible to extend the life by reducing the stress amplitude in the circumferential direction generated at the outer peripheral edge of the skirt portion, and it is possible to adjust the operation feeling by adjusting the curvature of the arc.

  In the movable contact member according to the present invention, the movable contact member may further include a leg portion extending radially outward from the outer peripheral edge portion of the skirt portion, and the skirt portion and the leg portion may be the skirt portion of the leg portion. It is characterized by being continuous so as to substantially coincide with a tangential direction of a tangent extending in the radial direction of the dome in a portion connected to the dome.

  According to this configuration, since the skirt portion and the leg portion are connected so as to substantially coincide with the tangential direction of the tangent line in the portion connected to the skirt portion of the leg portion, the skirt portion and the leg portion are connected gently. The operating force applied to the movable contact member is received not only at the leg portion but also at the skirt portion. Accordingly, the repeated stress operation of the movable contact member reduces the circumferential stress amplitude generated in the outer peripheral edge portion of the leg portion, thereby extending the life of the movable contact member. In addition, it is not limited only to connect so that it may correspond to the tangential direction in the part connected to the skirt part of a leg part completely, and an operating force is not received only by a leg part. It is only necessary to match the tangential direction within such a range, that is, within a range that does not block stress transmission from the outside toward the center during the pressing operation.

  The switch device of the present invention includes the above-described movable contact member, and a switch base having a fixed contact on which the movable contact member is arranged and separated from and in contact with the bulging portion.

  According to this configuration, the life of the movable contact member can be extended and the switch device can be maintained at a predetermined quality.

  ADVANTAGE OF THE INVENTION According to this invention, while making it easy to adjust an operation feeling, the stress amplitude of the circumferential direction in an outer peripheral part can be reduced, and lifetime can be achieved.

It is a figure which shows embodiment of the movable contact member which concerns on this invention, and is a perspective view of a switch apparatus. It is a figure which shows embodiment of the movable contact member which concerns on this invention, and is an exploded perspective view of a switch apparatus. It is a figure which shows embodiment of the movable contact member which concerns on this invention, and is explanatory drawing of a movable contact member. It is explanatory drawing of the modification of the movable contact member which concerns on this invention. It is explanatory drawing of the conventional movable contact member which concerns on the comparative example of the movable contact member which concerns on this invention. It is a figure which shows embodiment of the movable contact member which concerns on this invention, and is explanatory drawing of the stress pattern in a part of movable contact member. It is a figure which shows embodiment of the movable contact member which concerns on this invention, and is explanatory drawing of the inversion operation | movement of a movable contact member. It is a figure which shows embodiment of the movable contact member which concerns on this invention, and is a figure which shows the load-displacement curve of a movable contact member. It is a figure which shows embodiment of the movable contact member which concerns on this invention, and is a figure which shows the relationship between the operating force of a movable contact member, and a click rate. It is explanatory drawing of the other modification of the movable contact member which concerns on this invention.

In the switch device to which the present invention is applied, it is desired to reduce the diameter of the movable contact member as the electronic device is downsized. In general, in a disk that receives a concentrated load at the center, the stress amplitude σ in the circumferential direction generated at the outer peripheral edge of the disk is expressed by the following equation (1) where φ is the diameter of the disk and t is the thickness of the disk. As shown in FIG. 3, the diameter increases in inverse proportion to the square of the diameter of the disk.
σ∝t / φ ² (1)
Therefore, due to the reduction in the diameter of the movable contact member, a large stress amplitude is generated in the circumferential direction at the outer peripheral edge of the movable contact member.

  Further, the present applicant describes the circumferential stress amplitude generated at the outer peripheral edge of the movable contact member and the life of the movable contact member (here, the number of keystrokes of repeated pressing operations in which a crack occurs in the movable contact member). As a result of investigating the relationship, it was confirmed that the lifetime decreased logarithmically with increasing stress amplitude. As described above, the decrease in the diameter of the movable contact member increases the stress amplitude in the circumferential direction generated at the outer peripheral edge, greatly reducing the life of the movable contact member. It is important to reduce the stress amplitude in the circumferential direction generated at the outer peripheral edge of the steel sheet.

  Here, when the movable contact member is formed by simply combining the dome-shaped bulge portion and the skirt portion connected to the bulge portion, the operating force applied to the movable contact member is received only by the skirt portion. The circumferential stress amplitude generated at the outer peripheral edge of the movable contact member increases. This is because the direction of stress transmission is changed when a fulcrum is generated at the connecting part between the bulging part and the skirt part during the pressing operation. This is because transmission is interrupted at the boundary (connecting portion) between the bulging portion and the skirt portion. Therefore, when the diameter of the movable contact member described above is reduced, sufficient life performance cannot be obtained in a state in which a desired operating force and operation feeling are maintained.

  Therefore, as a result of examining the connection shape between the bulging portion and the skirt portion, the applicant of the present application substantially matches the tangential direction of the tangent line extending in the dome radial direction at the boundary between the bulging portion and the skirt portion. It was discovered that the stress transmission is not interrupted by connecting the skirts gently. That is, the essence of the present invention is to reduce the stress amplitude at the outer peripheral edge, which is increased by reducing the diameter of the movable contact member, by suppressing the interruption of stress transmission at the connecting portion between the bulging portion and the skirt portion. This is to extend the life of the member.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings. The switch device of the present invention is mainly attached to various electronic devices such as a mobile phone, a remote controller, an audio device, and an electronic camera, and functions as an input operation unit. With reference to FIG. 1, the overall configuration of the switch device will be described. FIG. 1 is a perspective view of a switch device according to an embodiment of the present invention. FIG. 2 is an exploded perspective view of the switch device shown in FIG.

  As shown in FIGS. 1 and 2, the switch device 1 according to the present embodiment is incorporated in a housing of an electronic device (not shown), and is mounted on a housing 2 whose upper surface is opened, and an opening of the housing 2. And a cover member 3 that forms a storage portion. In the housing portion, a movable contact member 4 placed on the bottom wall of the housing 2 and an operation key 5 that abuts on the upper portion of the movable contact member 4 to reversely move the movable contact member 4 are housed.

  The housing 2 is formed in a box shape having an upper surface opened by an insulating material. Positioning projections 11 for positioning the cover member 3 are formed at the four corners of the side wall portion of the housing 2 so as to protrude upward from the upper surface. The bottom wall portion of the housing 2 is provided with a central fixed contact portion 13 located at the center and a pair of outer fixed contact portions 14 positioned opposite to each other with the central fixed contact portion 13 interposed therebetween. The portion 13 and the pair of outer fixed contact portions 14 are slightly projected into the housing portion. The central fixed contact portion 13 and the pair of outer fixed contact portions 14 are connected to an external terminal 15 via a conductor pattern (not shown), and are connected to a substrate of an electronic device (not shown) via the external terminal 15.

  The cover member 3 is formed in a plate shape having a substantially square shape when viewed from above. Cutouts 17 are formed at the four corners of the cover member 3, and the cover member 3 is positioned front-rear and left-right with respect to the housing 2 by engaging the cutouts 17 with the positioning protrusions 11 of the housing 2. . A circular opening 18 for exposing the key top of the operation key 5 to the outside is formed in the center of the cover member 3.

  The movable contact member 4 is formed in a thin and substantially dome shape using a conductive material such as a metal plate. The movable contact member 4 is placed on the pair of outer fixed contact portions 14 with the bulging direction facing upward, and the central portion thereof is positioned directly above the central fixed contact portion 13. When the movable contact member 4 is reversed by the pressing operation, the central portion of the movable contact member 4 is brought into contact with the central fixed contact portion 13, and the central fixed contact portion 13 and the pair of outer fixed contact portions 14 connect the movable contact member 4. Through. The detailed configuration of the movable contact member 4 will be described later.

  The operation key 5 includes a columnar head portion 21, a flange portion 22 having a substantially square shape when viewed from the top from the lower side of the head portion 21, and a columnar pressing protrusion portion that protrudes downward from the center of the flange portion 22. 23 (see FIG. 7). The head portion 21 is formed to have a slightly smaller diameter than the circular opening 18 of the cover member 3, and protrudes to the outside from the housing portion via the circular opening 18. The flange portion 22 prevents the operation key 5 from coming off, and comes into contact with the lower surface of the cover member 3 when the movable contact member 4 is returned. The pressing protrusion 23 protrudes so as to contact the apex portion of the movable contact member 4, and concentrates the pressing force applied to the operation key 5 on the apex portion of the movable contact member 4.

  The movable contact member will be described in detail with reference to FIG. 3A and 3B are explanatory views of the movable contact member according to the embodiment of the present invention, in which FIG. 3A is a perspective view of the movable contact member, FIG. 3B is a sectional view of the movable contact member cut in a radial direction, and FIG. ) Is a partially enlarged view of (b). FIG. 4 is an explanatory view of a modification of the movable contact member according to the embodiment of the present invention, where (a) is a perspective view of the movable contact member, and (b) is a cut of the movable contact member in the radial direction. Sectional drawing and (c) are the elements on larger scale of (b).

  As shown in FIGS. 3A and 3B, the movable contact member 4 includes a bulging portion 25 that bulges in a dome shape, and a radially outward direction from the outer peripheral edge portion 25a of the bulging portion 25 downward. And a widening skirt portion 26. Therefore, since the skirt part 26 is formed continuously to the outer peripheral edge part 25 a of the bulging part 25, the skirt part 26 is to support the bulging part 25. The bulging portion 25 is formed to be curved with a predetermined curvature, and the skirt portion 26 is formed to be inclined at a predetermined angle. In this case, the bulging portion 25 is gently connected to the skirt portion 26 so that a fulcrum serving as an inflection point at the time of inversion is not formed at the boundary between the bulging portion 25 and the skirt portion 26.

  Further, as shown in FIG. 3C, the tangent line T <b> 1 extending in the radial direction of the dome in contact with the outer peripheral edge 25 a of the bulging portion 25 has an inclination angle (tangential direction) with the horizontal plane H being the inclination of the skirt portion 26. Is matched to the angle. More specifically, when a virtual circle C1 is taken along the curved surface of the bulging portion 25 in the cross section along the radial direction of the movable contact member 4, the outer peripheral edge 25a of the bulging portion 25 of the virtual circle C1. The inclination angle between the tangent line T1 and the horizontal plane H coincides with the inclination angle of the skirt portion 26.

  Thus, since the skirt part 26 is extended in the tangent T1 direction from the outer peripheral edge part 25a of the bulging part 25, the bulging part 25 and the skirt part 26 are connected gently. With this configuration, during the reversal operation of the movable contact member 4, since no fulcrum is generated at the connection portion, stress transmission from the outside to the inside is not blocked at the boundary between the bulging portion 25 and the skirt portion 26. It is possible to reduce the stress amplitude generated at the outer peripheral edge of the.

  Here, the inclination angle formed by the tangent line T1 and the horizontal plane H and the inclination angle of the skirt portion 26 coincide with each other. However, the present invention is not limited to this structure, and the difference between these inclination angles is the reversal operation of the movable contact member 4. It suffices if it is within an angular range that does not interrupt stress transmission from the outside toward the center. That is, it is only necessary that the extending direction of the skirt portion 26 is close enough not to block the stress transmission from the outside toward the center during the reversing operation with respect to the tangential T1 direction.

  Moreover, instead of the configuration in which the skirt portion is inclined linearly as described above, the skirt portion may be curved as shown in FIG. As shown in FIGS. 4A and 4B, in the movable contact member 31 according to the modified example, the bulging portion 32 is formed to be curved in a convex shape with a predetermined curvature, and the skirt portion 33 is a predetermined portion. It is formed to be concavely curved with a curvature of. In this case, the bulging portion 32 is gently connected to the skirt portion 33 so that a fulcrum at the time of reversal is not formed at the boundary between the bulging portion 32 and the skirt portion 33.

  Further, as shown in FIG. 4C, the inclination angle (tangential direction) formed between the tangent line T2 extending in the radial direction of the dome in contact with the outer peripheral edge portion 32a of the bulging portion 32 and the horizontal plane H is bulging of the skirt portion 33. It is in agreement with the inclination angle formed by the tangent T3 extending in the radial direction of the dome and the horizontal plane H in contact with the portion 33a connected to the protruding portion 32. More specifically, when a virtual circle C2 along the curved shape of the bulge portion 32 and a virtual circle C3 along the curved shape of the skirt portion 33 are taken in the cross section along the radial direction of the movable contact member 31, the virtual circle C3 is assumed. A tangent line T2 at the outer peripheral edge portion 32a of the bulging portion 32 of the circle C2 and a tangent line T3 at a portion 33a connected to the bulging portion 32 of the skirt portion 33 of the virtual circle T3 are connected in a straight line. In other words, the virtual circle C2 is a circumscribed circle with respect to the tangent T3 of the virtual circle C3, and the virtual circle C3 is a circumscribed circle with respect to the tangent T2 of the virtual circle C2.

  Thus, since the skirt part 33 curves and continues from the outer peripheral edge part 32a of the bulging part 32 so as to have the tangent T2, the bulging part 32 and the skirt part 33 are smoothly connected. Even in the configuration according to this modification, stress transfer from the outside to the inside is interrupted at the boundary between the bulging portion 32 and the skirt portion 33 because no fulcrum is generated at the connection portion during the reversing operation of the movable contact member 31. Therefore, the stress amplitude generated at the outer peripheral edge of the skirt 33 can be reduced.

  Here, the inclination angle formed between the tangent line T2 and the horizontal plane H is the same as the inclination angle formed between the tangent line T3 and the horizontal plane H. However, the present invention is not limited to this configuration. It suffices if it is within an angle range that does not block stress transmission from the outside toward the center during the reversing operation of the member 31. That is, it is only necessary that the tangential T3 direction is close to the tangent T2 direction so as not to interrupt the transmission of stress from the outside toward the center during the reversing operation.

  Here, before explaining the stress pattern appearing on the movable contact member by the pressing operation, a conventional movable contact member according to the comparative example will be briefly described with reference to FIG. 5A and 5B are explanatory views of a conventional movable contact member according to a comparative example. FIG. 5A is a perspective view of the movable contact member, and FIG. 5B is a cross-sectional view of the movable contact member cut in the radial direction.

  As shown in FIGS. 5 (a) and 5 (b), in the conventional movable contact member 35, a bulging portion 36 that is convexly curved with a predetermined curvature and a skirt portion 37 that is inclined at a predetermined angle, It is connected to bend. That is, the inclination angle formed between the tangent line extending in the dome radial direction in contact with the outer peripheral edge portion of the bulging portion 36 and the horizontal plane does not coincide with the inclination angle of the skirt portion 37. As described above, the conventional movable contact member 35 is formed such that the connection portion between the bulging portion 36 and the skirt portion 37 is slightly angular.

  Hereinafter, with reference to FIG. 6, the stress pattern of the movable contact member which concerns on this Embodiment, the movable contact member which concerns on a modification, and the movable contact member which concerns on a comparative example is demonstrated. Each stress pattern is obtained from analysis by a finite element method.

  FIG. 6 is an explanatory diagram of a stress pattern in a part of the movable contact member, where (a) and (b) are movable contact members according to a comparative example, and (c) and (d) are movable according to the present embodiment. Contact members (e) and (f) respectively show stress patterns of the movable contact member according to the modification. In FIGS. 6A, 6C, and 6E, the solid line indicates the stress pattern during the non-pressing operation, and the broken line indicates the stress pattern during the pressing operation. FIGS. In (f), a solid line indicates a non-pressing operation, and a broken line indicates a pressing operation. Further, for convenience of explanation, the stress pattern in the case where the boundary between the bulging portion and the skirt portion is the same position is shown.

  As shown in FIG. 6A, in the movable contact member 35 according to the comparative example, a triangular stress pattern appears, and the stress has a peak value at the outer peripheral edge of the skirt portion 37. Further, the stress generated by the reversing operation of the movable contact member 35 spreads only in the circumferential direction without spreading in the radial direction. This is because the connecting portion between the bulging portion 36 and the skirt portion 37 is formed to be slightly angular, and as shown in FIG. 6B, the skirt portion 37 swells while standing upright during the reversing operation. A fulcrum is formed at the connecting portion with the protruding portion 36. For this reason, the transmission direction of the stress generated by the reversing operation of the movable contact member 35 is slightly changed at the fulcrum portion, and due to the influence of the change in the transmission direction, from the connection portion between the bulging portion 36 and the skirt portion 37 to the inside. It is because it spreads out.

  As described above, since the operating force applied to the movable contact member 35 is received only by the skirt portion 37, particularly the circumferential stress amplitude generated at the outer peripheral edge portion of the skirt portion 37 is increased. Further, as described above, the life of the movable contact member 35 has a relationship that it decreases logarithmically as the stress amplitude increases. Therefore, in the movable contact member 35 according to the comparative example, cracks are likely to occur in the outer peripheral edge portion, and a sufficient life cannot be obtained. In particular, when the diameter of the movable contact member 35 is reduced, the stress amplitude is inversely proportional to the square of the diameter, so the life is significantly shortened.

  On the other hand, as shown in FIG. 6C, in the movable contact member 4 according to the present embodiment, a triangular stress pattern appears as in the movable contact member 35 according to the comparative example. The generated stress spreads not only in the circumferential direction but also in the radial direction. This is because the skirt portion 26 is smoothly connected in a tangential direction from the outer peripheral edge portion 25a of the bulging portion 25, and therefore, as shown in FIG. A fulcrum is not formed at the connecting portion. Therefore, the transmission of the stress generated by the reversing operation of the movable contact member 4 is not affected at all by the connection portion between the bulge portion 25 and the skirt portion 26, and the inner side from the connection portion between the bulge portion 25 and the skirt portion 26. This is because it is not blocked.

  As described above, since the operating force applied to the movable contact member 4 is received not only by the skirt portion 26 but also by the bulging portion 25, it is generated at the outer peripheral edge portion of the skirt portion 26 as compared with the movable contact member 35 according to the comparative example. The stress amplitude in the circumferential direction is reduced by about 20 to 30%. Therefore, in the movable contact member 4 according to the present embodiment, the lifetime is logarithmically increased with respect to the decrease in the stress amplitude, so that the lifetime is significantly longer than that of the movable contact member 35 according to the comparative example. It becomes possible to do. In addition, even when the diameter of the movable contact member 4 is reduced, a desired life can be ensured.

  On the other hand, as shown in FIG. 6E, in the movable contact member 31 according to the modification, a stress pattern in which the stress in the radially inner portion is larger than the stress in the outer peripheral edge portion appears. 33 has a stress peak value closer to the inner side than the outer peripheral edge portion 33. Further, the stress generated by the reversing operation of the movable contact member 31 spreads not only in the circumferential direction but also in the radial direction. This is because the skirt portion 33 is gently connected so as to have a common tangent line from the outer peripheral edge portion 32a of the bulging portion 32, and therefore, as shown in FIG. No fulcrum is formed at the connecting portion during the reversing operation. Therefore, the transmission of stress generated by the reversing operation of the movable contact member 31 is not affected at all by the connection portion between the bulge portion 32 and the skirt portion 33, and the inside from the connection portion between the bulge portion 32 and the skirt portion 33. This is because it is not blocked.

  As described above, the operating force applied to the movable contact member 31 is received not only in the skirt portion 33 but also in the bulging portion 32, and the peak value of the stress is located on the inner side from the outer peripheral edge portion. Compared with the contact member 35, the circumferential stress amplitude generated at the outer peripheral edge of the skirt 33 is reduced to about half. Therefore, in the movable contact member 31 according to the modified example, it is possible to further increase the life as compared with the movable contact member 35 according to the comparative example and the movable contact member 4 according to the present embodiment. Further, even when the diameter of the movable contact member 31 is reduced, it becomes easier to secure a desired life.

  With reference to FIGS. 7 and 8, the reversing operation of the movable contact member will be briefly described. FIG. 7 is an explanatory diagram of the reversing operation of the movable contact member according to the embodiment of the present invention. FIG. 8 is a diagram showing a load-displacement curve of the movable contact member according to the embodiment of the present invention.

  As shown in FIG. 7A, in an initial state where the operation key 5 is not pressed, the operation key 5 is lifted upward by the elastic force of the movable contact member 4. In this case, the outer peripheral edge portion of the movable contact member 4 is in contact with the pair of outer fixed contact portions 14, and the central portion is separated from the central fixed contact portion 13. When the operation key 5 is pressed from this initial state, the pressing force is concentrated on the top of the movable contact member 4 via the operation key 5, and the movable contact member 4 starts to bend gradually from the outside in the radial direction toward the center.

  Furthermore, when the load applied to the movable contact member 4 becomes large and exceeds a predetermined load, the movable contact member 4 is reversed as shown in FIG. When the movable contact member 4 is reversed, the central portion of the movable contact member 4 is brought into contact with the central fixed contact portion 13, and the central fixed contact portion 13 and the pair of outer fixed contact portions 14 are electrically connected via the movable contact member 4. . When the operating force is removed from the movable contact member 4, the movable contact member 4 is restored by its own elastic force and pushes the operation key 5 upward.

Next, the reversing operation shown in FIG. 7 will be described with reference to the load-displacement curve of FIG. In the case of the movable contact member 4 according to the present embodiment, when the operation key 5 is pressed, the load applied to the movable contact member 4 gradually increases, and the peak load P _max is obtained at the displacement S1. Further, when the operation key 5 is pressed, the movable contact member 4 is reversed and the load applied to the movable contact member 4 is reduced, and the bottom load _Pmin is obtained at the displacement S2. In this case, the click rate of the movable contact member 4 is obtained by (peak load P _max −bottom load P _min ) / peak load P _max . In the movable contact member 4, the operation feeling is changed by the click rate and the operating force applied to the movable contact member.

  The adjustment of the operation feeling of the movable contact member will be described with reference to FIG. FIG. 9 is a diagram showing the relationship between the operating force of the movable contact member and the click rate according to the present embodiment. In FIG. 9, the adjustment area A1 is the adjustment area of the operation feeling in a state where the movable contact member according to the present embodiment has ensured a life longer than a predetermined period, and the adjustment area A2 is the predetermined value by the movable contact member according to the comparative example. The operation feeling adjustment areas in a state where the above-mentioned lifetime is ensured are shown.

  As shown in FIG. 9, the adjustment regions A1 and A2 of the movable contact member 4 according to the present embodiment and the movable contact member 35 according to the comparative example are regions in which the operation feeling can be adjusted by the operating force and the click rate. The adjustment area A1 has a wide range including the adjustment area A2. For example, when the click rate is 50%, the movable contact member 4 according to the present embodiment can have an operating force of about twice as much as that of the movable contact member 35 according to the comparative example. It becomes.

  In this case, when the diameter of the movable contact member 35 according to the comparative example is reduced, it is necessary to reduce the operating force of the movable contact member 35 in order to ensure a predetermined life, and a sufficient operation feeling cannot be obtained. . For example, in order to set the diameter of the movable contact member 35 according to the comparative example to 2.5 mm and obtain a life of about 300,000 times, the click rate is 50% and the operating force is about 0.8 N. . The operating force of a switch having a general operation feeling is 1.6 N, and the movable contact member 35 cannot obtain a desired operation feeling. In addition, it is possible to approximate the desired operation feeling by stacking two movable contact members 35, but in this case, the number of parts is increased by one point. On the other hand, when the diameter of the movable contact member 4 according to the present embodiment is 2.5 mm, the life can be increased to 300,000 times or more with a click rate of 50% and an operating force of 1.6 N.

  Thus, even when the movable contact member 4 according to the present embodiment is reduced in diameter compared to the movable contact member 35 according to the comparative example, the life of the movable contact member 4 is maintained while maintaining the operation feeling. It is possible to suppress the decrease. In FIG. 9, the adjustment area of the movable contact member 31 according to the modification is not described, but a wide adjustment area can be obtained also in the movable contact member 31 according to the modification.

  As described above, according to the movable contact member 4 according to the present embodiment, the bulging portion 25 and the skirt portion 26 are smoothly connected, and the stress transmission from the outside toward the center is transmitted to the bulging portion 25 and the skirt portion 26. It will not be blocked at the border. Therefore, the repeated stressing operation of the movable contact member 4 reduces the circumferential stress amplitude generated at the outer peripheral edge of the skirt portion 26, and the movable contact member 4 can have a long life. Further, since the bulging portion 25 and the skirt portion 26 are formed, the curvature of the bulging portion 25, the skirt portion 26 and the bulging portion 25 are compared with the movable contact member formed in a dome shape with a predetermined curvature. It is possible to obtain a desired operation feeling by adjusting the boundary position and the like.

  The movable contact member according to the present invention is not limited to the movable contact member according to the present embodiment and the movable contact member according to the modification. As shown in FIG. 10, as long as each part such as the bulging part and the skirt part forming the movable contact member is connected so as not to prevent the stress transmission from the outer peripheral edge part to the inside, any shape can be obtained. Also good. For example, the movable contact member shown in FIG. 10A has a bulged portion curved in a convex shape with a predetermined curvature and a skirt portion curved in a convex shape with a curvature different from that of the bulged portion. In this case, the part connected to the bulging part of the skirt part is formed so as to substantially coincide with a tangent extending in the radial direction of the dome in contact with the outer peripheral edge part of the bulging part.

  Further, the movable contact member shown in FIG. 10 (b) has a bulging portion curved in a convex shape with a predetermined curvature, and the skirt portion curved in a concave shape with a curvature different from that of the bulging portion. Is horizontal. Also in this case, the portion of the skirt portion that is connected to the bulging portion is formed so as to substantially coincide with a tangent line that is in contact with the outer peripheral edge portion of the bulging portion and extends in the dome radial direction.

  Further, like the movable contact member shown in FIGS. 10C and 10D, a leg portion may be further connected to the outer peripheral edge portion of the skirt portion. In the movable contact member shown in FIGS. 10C and 10D, the bulging portion is curved in a convex shape with a predetermined curvature, the skirt portion is inclined at a predetermined angle, and the curved portion is convex in a predetermined curvature or It is concavely curved. In this case, the portion connected to the bulging portion of the skirt portion is formed so as to be substantially coincident with the tangential direction of the tangent extending in the radial direction of the dome in contact with the outer peripheral edge portion of the skirt portion, and the outer peripheral edge of the skirt portion. The portion is formed so as to substantially coincide with a tangential direction of a tangent extending in the radial direction of the dome in contact with a portion connected to the outer peripheral edge portion of the skirt portion of the leg portion. Note that the term “substantially coincidence” as used herein is not limited to perfect coincidence, and may have some deviation as long as the stress transmission from the outside to the inside is not blocked by the pressing operation.

  In the above-described embodiment, the bulging portion is formed with a predetermined curvature. However, the present invention is not limited to this configuration. The bulging portion may be any shape as long as it is smoothly connected to the skirt portion and receives a pressing force from a pressing member such as an operation key.

  In the above-described embodiment, the switch device in which the movable contact member is held in the housing has been described as an example. However, the present invention is not limited to this configuration. As long as it is a switch device using the movable contact member according to the present invention, any configuration may be used. For example, a sheet-type switch device in which the movable contact member is held on the substrate by a holding sheet may be used.

  The embodiment disclosed this time is illustrative in all respects and is not limited to this embodiment. The scope of the present invention is shown not by the above description of the embodiments but by the scope of the claims, and is intended to include all modifications within the meaning and scope equivalent to the scope of the claims.

  As described above, the present invention has the effect of facilitating adjustment of the operation feeling and reducing the stress amplitude in the circumferential direction at the outer peripheral edge portion, thereby prolonging the service life. It is useful for a movable contact member and a switch device incorporated in a small electronic device such as a telephone.

DESCRIPTION OF SYMBOLS 1 Switch apparatus 2 Housing 3 Cover member 4, 31 Movable contact member 5 Operation key 11 Positioning projection part 13 Center fixed contact part 14 Outer fixed contact part 15 External terminal 17 Notch part 18 Circular opening 21 Head part 22 Flange part 23 Pressing projection part 25, 32 Swelling part 26, 33 Skirt part C1, C2, C3 Virtual circle T1, T2, T3 Tangent A1, A2 Adjustment area

Claims (5)

A bulge that bulges into a dome shape;
A skirt that extends radially outward from the outer peripheral edge of the bulging portion;
The movable contact member, wherein the skirt portion is continuous from the outer peripheral edge portion of the bulging portion so as to substantially coincide with a tangential direction of a tangent extending in the radial direction of the dome at the outer peripheral edge portion of the bulging portion. . 2. The movable contact member according to claim 1, wherein the skirt portion is formed in a straight line along a tangential direction of a tangent extending in a radial direction of the dome at an outer peripheral edge portion of the bulging portion.   2. The movable contact member according to claim 1, wherein the skirt portion is formed along a circumscribed circle with respect to a tangent extending in the radial direction of the dome at the outer peripheral edge of the bulged portion. Having leg portions that continuously extend radially outward from the outer peripheral edge of the skirt portion;
The said skirt part and the said leg part are continuing so that it may correspond substantially to the tangent direction of the tangent extended in the dome radial direction in the part connected to the said skirt part of the said leg part. Item 4. The movable contact member according to any one of Items 3 to 4.   A movable contact member according to any one of claims 1 to 4, and a switch base having a fixed contact in which the movable contact member is disposed and separated from and in contact with the bulging portion. Switch device to do.

Images