JP6446682B2 - Contact rubber switch - Google Patents

Description

  The present invention relates to a contact rubber switch that performs input by conducting contact with a conductive contact of a circuit board.

  The contact rubber switch is fixed inside the electronic device, and is used to input conduction to the conductive contact of the circuit board by pressing the contact portion. As a method for fixing the contact rubber switch inside the electronic device, there are a method of screwing it to a structural member such as a casing or a circuit board, or a method of sandwiching it with a resin component forming the structural member. However, these methods require a screw for fixing the contact rubber switch and a resin part having a sandwiching structure, which increases the number of parts and increases the number of assembly steps.

  On the other hand, there is also a method of fixing the contact rubber switch by providing an engagement hole in a resin component forming a circuit board or a structural member, and providing a boss portion to be inserted and fixed in the contact rubber switch. Conceivable. FIG. 5 shows an example thereof. A base portion 2 of a contact rubber switch 1 made of a rubber-like elastic body such as silicone rubber is provided with a boss portion 3 projecting downward, and the boss portion 3 engages with a circuit board or the like. The engaging portion 4 is provided in a form that swells in an annular shape so as to surround the outer periphery of the boss portion 3 (see Patent Documents 1 and 2). According to this, it is possible to easily fix the contact rubber switch 1 to a circuit board or the like while reducing the number of parts and the number of assembly steps.

Japanese Utility Model Publication No. 2-104398, FIGS. 3 and 4 Japanese Utility Model Publication No. 2-37425, FIG. 2 (A)

  By the way, the engagement part 4 for fixing the contact rubber switch 1 is more strongly engaged with the mounting target member such as a circuit board or a structural member so that the engagement part 4 does not come off from the boss part 3 as the height protruding from the boss part 3 increases. Can be fixed. However, in that case, when the molded contact rubber switch 1 is removed from the mold, it is difficult to remove the engaging portion 4, and the boss portion 3 is cut off, resulting in a defective product. Part 3 remains in the mold. In order to prevent such inconvenience, it takes time for demolding and it is difficult to shorten the cycle time.

  As a countermeasure against such boss portion 3 tearing, for example, it is conceivable to make the rubber hardness of the contact rubber switch 1 low to make it soft and easy to come off. However, if it does so, it will become difficult to obtain required load characteristics with a small pressing load of the contact rubber switch 1. Moreover, even if the rubber hardness is lowered somewhat, the demolding property does not greatly improve, so that it does not lead to a reduction in cycle time after all.

  The present invention has been made against the background of the prior art as described above. The purpose of the contact rubber switch having a boss part with an engagement part is to have a suitable load characteristic as a contact rubber switch, and to securely remove it from the molding die while realizing secure fixing to the mounting target member. It is to make it easy.

  In order to achieve the above object, the present invention provides the following contact rubber switch.

  That is, the present invention relates to a contact rubber switch having a base portion made of a rubber-like elastic body and fixed to an attachment target member, and a contact portion in contact with a conductive contact, the surface of the base portion facing the attachment target member. A boss portion to be inserted into the attachment target member, and the boss portion includes an engaging portion that bulges in a direction intersecting with the axial direction of the boss portion, and does not bulge from the outer peripheral surface of the boss portion. It has a plane part which forms the side of the above-mentioned engaging part.

  The boss portion of the present invention includes an engaging portion that bulges in a direction intersecting with the axial direction of the boss portion, and a flat portion that forms the side surface of the engaging portion without bulging from the outer peripheral surface of the boss portion. Therefore, the engaging part of the present invention does not protrude annularly over the entire circumference of the boss part. That is, it has a flat surface portion that forms the side surface of the engaging portion without bulging from the outer peripheral surface of the boss portion. For this reason, at the time of demolding from the molding die, the flat portion is not caught in the cavity of the die. Therefore, unlike the conventional contact rubber switch in which the engaging part of the boss part is caught in the cavity over the entire circumference, it can be easily removed without breaking. And since it is not damaged, it is not necessary to lower the rubber hardness of the rubber-like elastic body forming the contact rubber switch, and an appropriate load characteristic can be exhibited as the contact rubber switch. Of course, reliable fixing to the attachment target member can be realized by the engaging portion of the boss portion.

  The base portion has a plurality of the boss portions on the facing surface, and the flat portions of the plurality of boss portions can be formed in parallel to each other.

  According to this, while the base portion is securely fixed by the engaging portions of the plurality of boss portions, the plurality of boss portions are separated from the molding die by aligning the flat portion in the pulling direction when removing the mold. Can be removed more easily.

  The boss portion is formed to have a tip end side narrower than a base end side sandwiching the engaging portion.

  According to this, it is easy to insert the boss part into the attachment target member, and workability can be improved. Moreover, since the base end side is thick, the boss portion 13 can be engaged with an attachment portion such as an engagement hole in the attachment target member without a gap.

  The engagement portion bulges larger in the crossing direction on the proximal end side than on the distal end side of the boss portion.

  According to this, since the engaging portion is thick on the proximal end side and thin on the distal end side, it is easy to insert the engaging portion into the attachment target member, and the proximal end of the engaging portion is against pulling in the pulling direction. It can be difficult to get caught on the side.

  The engaging portion is inclined at a larger angle of inclination of the bulging surface with respect to the axial direction on the proximal end side than on the distal end side of the boss portion.

  According to this, since the inclination angle of the bulging surface forming the outer surface of the engaging portion is greatly inclined on the base end side rather than the distal end side, the engaging portion can be easily inserted into the attachment target member, and the removal direction Can be prevented from being pulled out by the bulging surface on the proximal end side where the engaging portion is greatly inclined.

  According to the contact rubber switch of the present invention, to the attachment target member to be fixed by the flat portion of the engagement portion while having an appropriate load characteristic as the contact rubber switch and realizing reliable fixation to the attachment target member. Can be easily inserted and fixed, and can be easily removed from the molding die without breaking the boss. Therefore, it is possible to efficiently perform the fixing operation to the attachment target member, and it is possible to shorten the cycle time of the mold forming.

The front view of the contact rubber switch by one Embodiment. The right view of FIG. The top view of FIG. FIG. 3 is a sectional view taken along line SA-SA in FIG. 2. Sectional drawing of the contact rubber switch by one prior art example.

  Hereinafter, an embodiment of the present invention will be described with reference to the drawings.

  The contact rubber switch 10 according to the present embodiment is a molded body formed by molding a rubber-like elastic body. The structure includes a base portion 11, a contact portion 12 that protrudes upward from the upper surface 11 a of the base portion 11, and a boss portion 13 that protrudes downward from the lower surface 11 b of the base portion 11.

  As a rubber-like elastic body used as the material of the contact rubber switch 10, a known synthetic rubber or thermoplastic elastomer can be used. Among these, silicone rubber is preferable because it has a small compression set and good properties such as heat resistance. The rubber hardness is measured using a type A durometer based on JISK6253, and those between A30 and 70 can be used as those suitable for the contact rubber switch 10 that performs the pressing operation described later, but those of A40 to 60 are particularly preferable. . If it is smaller than A40, it is difficult to satisfy the load characteristics required for the contact rubber switch 10, and the mold release property from the molding die also deteriorates. Moreover, when larger than A60, the demolding property from a shaping die will fall and it will become easy to break. In this embodiment, the rubber hardness is A50.

  The base part 11 is formed in a sheet shape. The planar shape is substantially square as shown in FIG. 3, but is not limited thereto, and can be formed in any shape. The lower surface 11b of the base portion 11 is formed as a flat surface having no irregularities except for the contact portion 12 and the boss portion 13, and is placed so as to follow the surface shape of the circuit board P as the attachment target member. Is done. Therefore, if there is a mounting element or the like directly under the lower surface 11b, it is placed so as to cover it. In this embodiment, the circuit board P is exemplified as the “attachment target member”, but a resin component that is a structural member such as a casing of the electronic device may be used as the “attachment target member”. Alternatively, for example, a circuit board may be installed on a structural member such as a housing, and both or both of them may be included as other “attachment target members” that are inserted and fixed.

  The contact portion 12 is formed by a base portion 12a, a flexible portion 12b, and a conductive contact 12c provided at the tip of the base portion 12a. When a load for displacing the base portion 12a is applied by the pressing operation, the flexible portion 12b bends and the conductive contact 12c comes into contact with the circuit contact P1 of the circuit board P located below, so that a switch input is made. The base portion 12a is formed in a thick disk shape, and an operation button (not shown) made of a hard resin that is exposed and pressed on the casing of an electronic device (not shown) is installed on the upper surface 12d. In addition, it is good also as a press operation part which exposes the upper surface 12d of the base 12a to the outer surface of the housing | casing of an electronic device, without providing such an operation button. The flexible portion 12b is formed in a truncated cone shape extending in a skirt shape from the lower end of the base portion 12a. The flexible portion 12b is formed thinner than the base portion 12a so as to be easily bent, and exhibits an operational feeling with a click feeling when buckled by a pressing operation. The conductive contact 12c is formed of a conductive member, for example, a conductive coating film or a metal layer.

  In the present embodiment, two boss portions 13 are formed so as to protrude downward from the lower surface 11 b of the base portion 11. Note that the number is not limited to two but may be one or more. The boss portions 13 have the same shape, and a base end portion 13a, an engaging portion 13b, and a tip end portion 13c are formed in this order from the base portion 11 side.

  Both the base end portion 13a and the tip end portion 13c have a cylindrical shape, and the tip end portion 13c is formed with a smaller diameter than the base end portion 13a, and can be easily inserted into the engagement hole P2 of the circuit board P. It has become. On the other hand, the base end portion 13a having a diameter larger than that of the tip end portion 13c is slightly smaller than the engagement hole P2, and is securely fixed when inserted therethrough.

  In addition, the length of the base end portion 13a is formed to have a depth along the hole axis direction of the engagement hole P2 of the circuit board P, that is, substantially the same as the plate thickness of the circuit board P. On the other hand, the front end portion 13c is formed longer than the thickness of the circuit board P and the base end portion 13a so that the insertion state of the front end portion 13c inserted into the engagement hole P2 can be maintained first. . That is, if the engaging portion 13b passes through the engaging hole P2, the boss portion 13 cannot be easily removed. However, if the tip portion 13c is short, there is a possibility that the boss portion 13 may come out of the engaging hole P2 when only the tip portion 13c is inserted. For this reason, by increasing the length of the distal end portion 13c, it is difficult to remove even when only the distal end portion 13c is inserted. Specifically, the length of the tip of the tip 13c penetrates the engagement hole P2 and protrudes from the edge of the hole with only the tip 13c inserted into the engagement hole P2.

  The engaging portion 13b is formed at two locations for one boss portion 13. That is, it is an outer peripheral surface portion located on the opposite side with respect to the axial center of the boss portion 13. The engaging portion 13b has a shape in which the base end portion 13a side is thick and the tip end portion 13c side is thin. A shoulder portion 13d is formed on the side of the base end portion 13a of the engaging portion 13b. This shoulder portion 13d is caught by the hole edge and the hole wall (inner wall) of the engaging hole P2 of the circuit board P and exhibits a resistance force. The part 13 is retained. Accordingly, the bulging surface (inclined surface) 13e forming the shoulder portion 13d rises and projects at a steep inclination angle with respect to the axial direction of the boss portion 13. The lower end of the shoulder portion 13d is formed with a protruding portion 13f that protrudes outwardly beyond the hole diameter of the engaging hole P2 in the engaging portion 13b. The protruding portion 13f is a portion that is press-fitted into the engagement hole P2 of the circuit board P. A bulging surface 13g that is gently inclined toward the axial direction of the boss portion 13 is formed at the lower end of the protruding portion 13f. The bulging surface 13g guides the press-fitting of the boss portion 13 into the engagement hole P2 so that the insertion resistance gradually increases.

  On both side surfaces of the engaging portion 13b that bulges as described above, the base end portion 13a and the distal end extend in the radial direction of the boss portion 13 and extend on the extended line of the outer surface of the base end portion 13a of the boss portion 13. A flat portion 13h that does not protrude from the portion 13c is formed. The flat surface portion 13h is formed as a side surface of the engaging portion 13b of each of the two boss portions 13 and 13. The space between the flat surface portions 13h has the same length as the outer diameter of the base end portion 13a. Therefore, the space between the flat portions 13h is longer than the outer diameter of the tip portion 13c.

  The two flat portions 13h of one boss portion 13 are formed in parallel to each other, and the flat portion 13h is provided so that it is not broken by being caught in the mold when being removed from the mold cavity after molding. Therefore, it can be easily removed. Further, the flat portions 13h of the two boss portions 13 are formed in parallel to each other. This is also to facilitate demolding after molding. And when inserting in the engagement hole P2 of the circuit board P, insertion resistance does not generate | occur | produce over the perimeter of the boss | hub part 13, but rather than the engagement part 13b, the insertion resistance which generate | occur | produces in the plane part 13h is produced. Since it can be made smaller, the contact rubber switch 10 can be attached to the circuit board P more easily than in the prior art.

  In addition to being parallel to each other, the plane portions 13h of the two boss portions 13 are arranged in parallel so that the plane portions 13h face each other. The contact rubber switch 10 can be stably fixed to the circuit board P by arranging the plane portions 13h in parallel and in parallel. If the flat portions 13h of the two boss portions 13 are arranged along the same straight line, when the base portion 11 is pulled in the extending direction of the flat portion 13h, the boss portions 13 that move back and forth in the turning direction are formed. Since it is engaged with the engagement hole P2 one by one with a time difference and is prevented from coming off, it is easy to come off with a small removal force. On the other hand, when the flat portions 13h of the boss portions 13 are arranged in parallel, the two boss portions 13 arranged in parallel in the turning direction are pulled when pulled in the same manner. At the same time, it engages with the engagement hole P2 and is prevented from coming off. Therefore, it can be made more difficult to come off.

  Furthermore, in the present embodiment, the flat portions 13h of the boss portions 13 are arranged in parallel and in parallel on both sides with the contact portion 12 as the center. As a result, even if the contact portion 12 is repeatedly displaced and moved with elastic deformation by the pressing operation, the base portion 11 can be securely fixed to the circuit board P reliably on both sides of the contact portion 12.

  The contact rubber switch 10 of the present embodiment as described above is fixed by inserting the boss portion 13 into the engagement hole P2 of the circuit board P. At this time, the boss portion 13 is pressed into the engagement hole P2 so as to be pressed from the upper surface 11a side of the base portion 11. In order to facilitate the press-fitting, it is preferable to insert the boss portion 13 at a slight angle so that the engaging portion 13b of the boss portion 13 is inserted into the engaging hole P2 one side at a time. This is because the insertion resistance is maximized when the bulging surfaces 13g and the protruding portions 13f of the two boss portions 13 are simultaneously press-fitted into the engagement holes P2.

  When the contact rubber switch 10 is removed from the circuit board P, the shoulder portions 13d of the boss portions 13 are not simultaneously caught in the engagement holes P2, as in the insertion at the time of attachment. Further, all the shoulder portions 13d of the two boss portions 13 are prevented from being simultaneously caught in the engagement holes P2. In this way, it is possible to remove the hook more easily by shifting the catch by the shoulder portion 13d in terms of time.

  According to the contact rubber switch 10 as described above, since it is not necessary to reduce the rubber hardness of the rubber-like elastic body in consideration of the demolding property, the contact portion 12 (flexible portion) is used as the contact rubber switch 10. It is possible to exhibit appropriate load characteristics in 12b). In addition, reliable fixing to the circuit board P (attachment target member) can be realized. Furthermore, since the flat portion 13h is formed, it can be easily inserted into and fixed to the circuit board P to be fixed, and can be easily removed from the molding die. Therefore, there is an advantage that the fixing operation can be performed efficiently and the molding cycle time can be shortened.

  In the above embodiment, the boss portion 13 has the same shape, but the size of the plurality of boss portions 13 may be changed depending on the size of the engagement hole P2. Moreover, you may change the formation position of the engaging part 13b in the length direction of the boss | hub part 13. As shown in FIG.

  The boss portion 13 of the above embodiment has been shown in an example in which the flat surface portion 13h is arranged in parallel / parallel. Good.

  In the above embodiment, one example of the contact portion 12 is shown, but a plurality of contact portions 12 may be provided, and the shape of the contact portion 12 may be changed to another shape.

DESCRIPTION OF SYMBOLS 10 Contact rubber switch 11 Base part 11a Upper surface 11b Lower surface 12 Contact part 12a Base part 12b Flexible part 12c Conductive contact 12d Upper surface 13 Boss part 13a Base end part 13b Engagement part 13c Front end part 13d Shoulder part 13e Swelling surface 13f Projection part 13g Swelling Exit surface 13h Planar part P Circuit board (attachment target member)
P1 contact P2 engagement hole

Claims (7)

A base portion made of a rubber-like elastic body and fixed to a member to be attached;
In a contact rubber switch having a contact portion that contacts a conductive contact,
The base portion has a columnar boss portion to be inserted into an engagement hole formed in the attachment target member on a surface facing the attachment target member.
The boss is
A base end portion extending from the base portion;
An engagement portion that locks against the engagement hole and prevents the boss portion from coming off;
A plane portion forming a side surface adjacent to the engaging portion;
A tip portion that extends in the axial direction of the boss portion from the engagement portion and the flat portion to facilitate the insertion of the boss portion into the engagement hole;
The tip is formed with a smaller diameter than the engagement hole,
The engaging portion bulges outward in the radial direction of the boss portion at two locations on the outer peripheral surface portion located on the opposite side with the shaft center of the boss portion as the center. Has a protruding part,
The contact rubber switch according to claim 1, wherein the flat portion extends on an extension line of the outer surface of the base end portion, and is formed without protruding from the base end portion in the radial direction of the boss portion.   The contact rubber according to claim 1, wherein the tip has a length such that the tip of the tip penetrates through the engagement hole and protrudes from a hole edge of the engagement hole in a state where the tip is inserted into the engagement hole. switch.   3. The contact rubber switch according to claim 1, wherein the engaging portion has a shoulder portion having a bulging surface that is inclined while bulging outward from the base end portion in the radial direction of the boss portion. The base portion has a plurality of the boss portions on the facing surface,
The contact rubber switch according to any one of claims 1 to 3, wherein flat portions of the plurality of boss portions are formed in parallel to each other.   The contact rubber switch according to any one of claims 1 to 4, wherein the boss portion is formed so that a tip end side is narrower than a base end side sandwiching the engaging portion.   The contact rubber switch according to any one of claims 1 to 5, wherein a thickness of the engaging portion in a crossing direction with respect to the axial direction bulges larger on a proximal end side than on a distal end side of the boss portion.   The contact rubber switch according to any one of claims 1 to 6, wherein the engagement portion is inclined at a larger inclination angle on the base end side than the distal end side of the boss portion with respect to the axial direction. .

Images