JP2016143496A - Push-button switch - Google Patents

Abstract

PROBLEM TO BE SOLVED: To improve stability and reliability of switch operation so that no slide defect occurs.SOLUTION: A push-button switch accommodated in a case 20 and having a key top 31 positioned at an opening 23 of the case 20 comprises: the key top 31; a push button 30 having a shaft part 32 projected in the center of a reverse surface 31c thereof; a guide part 41 having a through hole 43 for guiding the shaft part 32 formed; a guide 40 having a support plate part 42 supporting the guide part 41; and a switch contact pressed by a tip of the shaft part 32 to be operated. Two ribs 33 extending axially are projected and formed on an outer peripheral surface of the shaft part 32 in directions which are not mutually different straight lines around the shaft, and a plurality of grooves 44 for guiding the ribs 33 to slide are formed on an inner peripheral surface of the through hole 43. There is provided at least one of a guide-side intrusion prevention wall 45 projected and formed on a support plate part 42 surrounding the guide part 41 and a push button-side intrusion prevention wall 34 projected and formed on the reverse surface 31c of the key top 31 surrounding the shaft part 32.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a push button switch that is arranged and used on an operation panel of various devices such as FA (Factory Automation) devices.

  8 and 9 show an outline of the switch operation panel described in Patent Document 1. The key top 11 of each switch is inserted into the key top guide 12, and the key top 11 in the key top operation direction. Is guided by the key top guide 12. The key top 11 is closed at the upper end of a substantially rectangular cylindrical peripheral wall, and its outer surface is a key top top surface 11a. The key top guide 12 is also a rectangular tube that is substantially coaxial with the cylinder of the key top 11. Yes.

  On the inner surface of the key top guide 12, one guide groove 13 parallel to the key top operating direction is formed on each of the three planes of the peripheral wall, and the outer peripheral surface protrudes by a protrusion corresponding to the guide groove 13. 14 is configured. A rib 15 inserted into the guide groove 13 is formed on the outer peripheral surface of the key top 11 in parallel with the key top operation direction. With these guide grooves 13 and ribs 15, the key top 11 is correctly held in the operation direction by the key top guide 12.

  The key top guide 12 is configured separately from a case (not shown) constituting the operation panel. Each key top guide 12 is inserted through a guide holding plate 16, and a part of the key top guide 12 is held between the guide holding plate 16 and the case. The case is provided with a hole through which each key top 11 faces the outside.

  The guide groove 13 is formed from the end surface opposite to the key top top surface 11a to the middle, and the key top top surface 11a side of the rib 15 is removed. When the key top 11 is pulled in the direction opposite to the operation direction, the upper end of the rib 15 engages with the upper end of the guide groove 13, so that the key top 11 does not come out.

  On the other hand, one side plate of the key top guide 12 is formed with a drop-off preventing piece 17 extending in the key top operating direction, and a protrusion is formed on the inner surface of the upper end of the drop-off preventing piece 17. The top of the key top 11 is engaged with the upper end of the drop-off prevention piece 17 and is prevented from dropping from the lower side. In FIG. 8, 18 is a switch element provided on a substrate (not shown) and operated by the key top 11, and 19 is a light emitting element for illumination attached to the substrate. The operation pin of the switch element 18 is in contact with the inner surface of the key top top surface 11a.

Japanese Patent Laid-Open No. 11-102622

  As described above, in the switch operation panel described in Patent Document 1, the three ribs 15 formed on the outer peripheral surface of the key top 11 are inserted into the guide grooves 13 formed in the key top guide 12 and guided. Thus, when the key top 11 is operated, there is almost no backlash, and stable switch operation is possible even if the corner of the key top 11 is pressed.

  However, since the guide structure including the rib 15 and the guide groove 13 is located at the peripheral edge of the key top 11, a liquid containing dust from a gap between the key top and the case in the hole of the case facing the outside of the key top 11 When dust, dust, or the like enters, the foreign matter easily enters the sliding portion between the rib 15 and the guide groove 13, which causes a situation where sliding failure occurs and the stability of the switch operation is impaired.

  In view of this problem, an object of the present invention is to provide a pushbutton switch that is less likely to cause a sliding failure, thereby having excellent switch operation stability and providing a good operation feeling.

  According to the first aspect of the present invention, the push button switch housed in the case and having the key top positioned in the opening formed in the case has the key top and a shaft portion that is formed to project at the center of the back surface of the key top. A push button, a guide having a through hole formed to receive and guide the shaft, a support plate that supports the guide, and a switch contact that is operated by being pushed by the tip of the shaft. A plurality of ribs extending in the axial direction of the shaft portion and projecting in directions different from each other in a different straight line around the shaft, and slidingly guiding the ribs respectively. Is formed on the inner peripheral surface of the through hole, and is formed on the support plate portion so as to protrude around the guide portion, or on the push button side formed on the back surface of the key top so as to protrude around the shaft portion. Intrusion prevention wall, at least One is assumed to be provided or.

  In the invention of claim 2, in the invention of claim 1, both the guide side intrusion prevention wall and the push button side intrusion prevention wall are provided.

  In the invention of claim 3, in the invention of claim 2, the guide side intrusion prevention wall and the push button side intrusion prevention wall are formed so as to alternate.

  In the invention of claim 4, in the invention of claim 2, the guide side intrusion prevention wall and the push button side intrusion prevention wall are formed at positions facing each other.

  According to a fifth aspect of the present invention, in the invention according to any one of the first to fourth aspects, the number of the ribs is two, and the ribs are formed at positions that are 90 ° to each other.

  In the invention of claim 6, in the invention of any one of claims 1 to 4, three ribs are formed at intervals of 90 °.

  According to the present invention, there is a low possibility that foreign matter will enter the sliding guide portion composed of the rib and the groove, so that a situation in which a sliding failure occurs is unlikely to occur. It is possible to obtain a push button switch that is excellent in performance and provides a good operational feeling.

Sectional drawing which shows the state in which one Example of the pushbutton switch in this invention was arranged and accommodated in the case. A is a partially enlarged view of FIG. 1, and B is a cross-sectional view showing a state where a pushbutton switch shown in A is operated. 1A is a plan view of the push button in FIG. 1, B is a front view thereof, C is a bottom view thereof, and D is a perspective view thereof. A is a top view which shows the principal part of the guide in FIG. 1, B is the perspective view. The top view which shows an example of the operation panel in which many pushbutton switches are accommodated in a case. A is a sectional view showing another embodiment of the pushbutton switch according to the present invention, and B is a sectional view showing a state in which the pushbutton switch shown in A is operated. A is a perspective view of a push button having four ribs, and B is a perspective view of a push button having two ribs. The top view which shows a part of the state which removed the case of the conventional switch operation panel. FIG. 9A is a bottom view showing a state in which the key top in FIG. 8 is inserted into the key top guide, and FIG.

  Embodiments of the present invention will be described with reference to the drawings.

  FIG. 1 shows a configuration of an embodiment of a pushbutton switch according to the present invention arranged and accommodated in a case, and FIG. 2A shows an enlarged view of one pushbutton switch portion.

  In FIG. 1, 21 indicates a front case, and 22 indicates a rear case. The pushbutton switch is accommodated in a case 20 including the front case 21 and the rear case 22. The push button switch includes a push button 30, a guide 40, a rubber sheet 50, and a substrate 60. The guide 40, the rubber sheet 50, and the substrate 60 are shared by a plurality of push button switches.

  FIG. 3 shows details of the push button 30, and the push button 30 includes a key top 31 and a shaft portion 32. The key top 31 has a rectangular cylindrical shape with one end closed, and the outer surface of the closed one end is an operation surface 31a. A flange 31b is formed on the outer periphery of the other end side of the key top 31 so as to protrude in a square shape.

  The shaft portion 32 has a cylindrical shape, and is formed so as to protrude from the center of the back surface 31c of the key top 31 (the surface opposite to the operation surface 31a). The shaft portion 32 has a length protruding from the other end of the key top 31, and a hole 32 a is provided at the center of the shaft portion 32. A rib 33 that protrudes in the radial direction of the shaft portion 32 and extends in the axial direction of the shaft portion 32 is formed over the entire length of the shaft portion 32 on the outer peripheral surface of the shaft portion 32. In this example, three ribs 33 are formed around the axis of the shaft portion 32 at intervals of 90 °.

  Further, in this example, a push button side intrusion prevention wall 34 having a cylindrical shape is formed to protrude from the back surface 31 c of the key top 31 so as to surround the shaft portion 32. The height (protrusion height) of the push button side intrusion prevention wall 34 is set so as not to protrude from the other end of the key top 31.

  FIG. 4 shows the structure of the main part of the guide 40. The guide 40 is provided with a guide part 41 for guiding the push button 30, and the guide part 41 is supported by a support plate part. The guide portion 41 has a cylindrical shape, and a through hole 43 is formed at the center thereof. A groove 44 extending in the through direction of the through hole 43 is formed on the inner peripheral surface of the through hole 43. Three grooves 44 are formed at intervals of 90 ° in the circumferential direction of the through hole 43 corresponding to the three ribs 33 of the push button 30, and are formed over the entire length of the through hole 43.

  A guide-side intrusion prevention wall 45 is formed on the guide 40. The guide-side intrusion prevention wall 45 has a cylindrical shape and is formed on the support plate portion 42 so as to surround the guide portions 41.

  Although not shown in detail in FIGS. 1 and 2 on the substrate 60, a pair of fixed contacts forming the constituent elements of the push button switch are formed at positions constituting the push button switches. The pair of fixed contacts are, for example, a pair of comb contacts formed so as to be engaged with each other.

  The substrate 60 is disposed and fixed on the inner surface of the rear case 22, and the rubber sheet 50 is mounted on the substrate 60. A columnar portion 51 is formed on the rubber sheet 50 so as to face each fixed contact of the substrate 60, and the columnar portion 51 is surrounded and supported by an elastically deformable skirt portion 52 so as to be movable up and down. A movable contact 53 is provided on the lower end surface of the columnar part 51. The movable contact 53 is formed, for example, by printing a conductive material, and the movable contact 53 and a pair of fixed contacts formed on the substrate 60 constitute a switch contact.

  The guide 40 is positioned on the rubber sheet 50 at a predetermined distance from the sheet portion 54 of the rubber sheet 50. The through hole 43 of each guide portion 41 of the guide 40 is located on each columnar portion 51 of the rubber sheet 50.

  The push button 30 is attached to the guide 40 with the shaft portion 32 inserted into the through hole 43 of the guide 40. The three ribs 33 formed on the shaft portion 32 are respectively accommodated in grooves 44 formed on the inner peripheral surface of the through hole 43, and the tip (lower end) of the shaft portion 32 is above the columnar portion 51 of the rubber sheet 50. Located on the end face.

  An opening 23 is formed in the front case 21 corresponding to each pushbutton switch, and the key top 31 of each pushbutton switch is located in the opening 23 and a part thereof protrudes from the front case 21. The key top 31 is prevented from being detached from the case 20 by the flange 31 b abutting against the inner surface of the front case 21. Although not shown in detail in FIG. 1, the rubber sheet 50 and the guide 40 are each positioned in the case 20 by a predetermined positioning structure.

  In the configuration as described above, the shaft portion 32 of the push button 30 is accommodated and guided in the through hole 43 of the guide 40, and when the operation surface 31 a of the key top 31 is pushed in, the tip of the shaft portion 32 is As a result, the columnar portion 51 of the rubber sheet 50 is pushed, the skirt portion 52 is deformed, and the columnar portion 51 is displaced downward. As a result, the movable contact 53 formed on the columnar portion 51 comes into contact with the pair of fixed contacts formed on the substrate 60, the pair of fixed contacts are conducted, and the switch contact is turned on. FIG. 2B shows a state in which the switch contact is operated and turned on in this way.

  On the other hand, when the pressing force to the key top 31 is released, the skirt portion 52 is elastically restored to the original state, and the switch contact is turned OFF when the movable contact 53 is separated from the pair of fixed contacts, and the push button 30 is returned to the original position. Return.

  As described above, three ribs 33 are formed on the shaft portion 32 of the push button 30, and three grooves 44 for slidingly guiding the ribs 33 are formed on the inner peripheral surface of the through hole 43 of the guide 40. In the example, the guide structure including the rib 33 and the groove 44 does not cause backlash or tilt when the push button 30 is operated, and a good operation feeling can be obtained.

  In this example, the guide structure including the rib 33 and the groove 44 is not located at the peripheral edge of the key top as in the prior art, but is located at the center of the back side of the key top 31, that is, the key top 31 faces the outside. The opening 23 of the front case 21 is located at a position away from the gap between the key top 31 and the front case 21. Therefore, even if foreign matter such as liquid containing dust, dust, or dust enters from the gap between the key top 31 and the front case 21, it is unlikely that the foreign matter will enter the sliding portion between the rib 33 and the groove 44. A situation in which a malfunction occurs is unlikely to occur.

  In addition, in this example, the guide 40 and the push button 30 are provided with a guide side intrusion prevention wall 45 and a push button side intrusion prevention wall 34, respectively. The guide side intrusion prevention wall 45 and the push button side intrusion prevention wall 34 are shown in FIG. As shown in FIG. 2, since they are formed in a staggered manner and are located in the foreign substance intrusion path, the possibility that the foreign substance enters the sliding portion between the rib 33 and the groove 44 is further reduced.

  FIG. 5 shows an operation panel of an FA device as an example of an operation panel in which pushbutton switches are accommodated and arranged in a case 20, and a large number of pushbutton switches (FIG. 5 shows pushbuttons 30 of the pushbutton switch). Are arranged in high density. In such an operation panel, for example, when it is required to reduce the size of the operation panel or increase the number of push button switches, it is inevitable that the pitch of the push button switches is narrowed. In this respect, in the conventional configuration example as shown in FIGS. 8 and 9, the guide structure including the rib 15 and the guide groove 13 is formed on the periphery of the key top 11, that is, from the operation surface of the key top 11 (key top top surface 11a). Since it is located outside, it is disadvantageous for narrowing the pitch. On the other hand, in the above-described embodiment of the present invention, the guide structure composed of the rib 33 and the groove 44 is located at the center on the back side of the key top 31, so that the structure is advantageous for narrowing the pitch.

  FIG. 6A shows another embodiment of the pushbutton switch according to the present invention, and FIG. 6B shows its operation state. In this example, the guide side intrusion prevention wall 45 and the push button side intrusion prevention wall 34 are formed not to be alternate but to face each other. The guide side intrusion prevention wall 45 and the push button side intrusion prevention wall 34 may be formed in such a positional relationship. Note that the guide-side intrusion prevention wall 45 and the push button-side intrusion prevention wall 34 do not necessarily have to be provided. For example, only the guide-side intrusion prevention wall 45 may be configured to increase the protruding height.

  On the other hand, for example, when there is a concern about the intrusion of oil (dirty oil) containing dust or chips, the oil enters through the surface, so the guide side intrusion prevention wall 45 and the push button side intrusion prevention wall 34 In order to increase the creepage distance, it is preferable to arrange them alternately as shown in FIGS.

  In the embodiment described above, three ribs 33 are provided around the axis of the shaft portion 32 of the push button 30 at 90 ° intervals. However, the number of the ribs 33 is not limited to three, and is, for example, the push button 30 ′ shown in FIG. 7A. Four may be provided at intervals of 90 °. Moreover, it is good also considering the number of the ribs 33 as the push button 30 '' shown to FIG. 7B. In FIG. 7B, the two ribs 33 are formed at positions that form 90 ° around the axis.

  Two ribs 33 may be formed in at least two directions that are not on a straight line different from each other around the axis, thereby suppressing backlash and tilting and enabling good switch operation. If the ribs 33 having no rotational symmetry such as the push button 30 shown in FIG. 3 or the push button 30 ″ shown in FIG. When the portion 32 is inserted, positioning in the rotational direction is performed, and the directions of the push buttons 30 and 30 ″ are uniquely determined. The groove 44 on the inner peripheral surface of the through hole 43 of the guide 40 is provided so as to correspond to the position and number of the ribs 33.

  Here, by providing the rib 33 on the shaft portion 32 of the push button 30 and providing the groove 44 for slidingly guiding the rib 33 in the through hole 43 that accommodates the shaft portion 32, the operability of the switch is improved. What can be achieved will be described.

  For example, when a simple cylindrical shaft portion is guided by a circular through hole, when the shaft portion tilts (falls down), the upper and lower two points hit the inner peripheral surface of the through hole and slide. In this case, cylindrical surfaces such as the outer peripheral surface of the shaft part and the inner peripheral surface of the through hole are generally difficult to finish with a good surface (mirror surface) with a small friction coefficient, so the sliding friction force increases and good switch operation Sex cannot be obtained.

  On the other hand, if the portion that slides when the shaft portion is guided by the through hole is limited to the inner wall of the rib and groove, the shape of the rib and groove is configured by a flat surface, so that mirror finish is easy. Even if the shaft portion is inclined and the rib and the inner wall of the groove slide, the sliding frictional force is small, and thus, good switch operability can be obtained.

  In the above-described embodiment, when the shaft portion 32 is inclined, the rib 33 is configured such that the side surface (side surface in the width direction) slides with the inner wall of the groove 44 instead of the front end surface in the protruding direction. For this reason, the clearance in the width direction between the rib 33 and the groove 44 is reduced, and the clearance in the protruding direction of the rib 33 is increased. That is, as shown in the embodiment, when the ribs 33 are formed at intervals of 90 °, even if the shaft portion 32 is inclined and the side surface of a certain rib 33 hits the inner wall of the groove 44, the rib 33 in the tilting direction. The front end surface in the protruding direction of the rib 33 in a direction shifted by 90 ° from the rib 33 where the inner wall and the side surface of the groove 44 are in contact with each other is prevented from contacting the inner wall of the groove 44. In this way, the sliding guided portion is limited to only the side surface of the rib 33, and if the clearance in the width direction of the rib 33 and the groove 44 is reduced, rattling and inclination during switch operation can be suppressed, and a good switch Operability can be realized. It should be noted that such good switch operability can be realized by providing at least two ribs 33 in directions that are not on different straight lines around the axis of the shaft portion 32.

  In the present invention, when the clearance in the width direction of the rib and the groove and the clearance of the conventional example including the columnar shaft portion and the circular through hole as described above have the same size, in other words, both effective Comparing the present invention and the above-described conventional example with respect to the case where it can be said that the clearance is equal and the amount of the same is equivalent to the rattling suppression, the present invention differs from the above-described conventional example in the present invention where the part does not participate in the sliding action for suppressing the rattling. More specifically, the clearance in the outer periphery of the shaft portion where no rib is provided and the protruding direction of the rib can be formed as a useless clearance space. As a result, the total volume of the gap that the present invention has between the shaft portion and the through hole is much larger than the volume of the gap that the conventional example has between the shaft portion and the through hole. And when foreign materials, such as dust and chips, intrude, in the present invention, it is highly probable that the foreign materials will retreat to the useless clearance space and reach a state where the sliding action is not hindered.

  In other words, in the above conventional example, the strict clearance that cannot be implemented because the sliding is immediately inhibited by the entry of a small amount of foreign matter, that is, the required specification for suppressing rattling is achieved while sufficiently avoiding the inhibition of the sliding. This is possible in the present invention.

DESCRIPTION OF SYMBOLS 11 Key top 11a Key top top surface 12 Key top guide 13 Guide groove 14 Projection 15 Rib 16 Guide holding plate 17 Fall-off prevention piece 18 Switch element 19 Light emitting element 20 Case 21 Front case 22 Rear case 23 Opening 30, 30 ', 30 '' Push button 31 Key top 31a Operation surface 31b Flange 31c Back surface 32 Shaft portion 32a Hole 33 Rib 34 Push button side intrusion prevention wall 40 Guide 41 Guide portion 42 Support plate portion 43 Through hole 44 Groove 45 Guide side intrusion prevention wall 50 Rubber sheet 51 Columnar part 52 Skirt part 53 Movable contact 54 Sheet part 60 Substrate

Claims (6)

A push button switch housed in a case and having a key top positioned in an opening formed in the case,
A push button having the key top and a shaft portion formed to project from the center of the back surface of the key top;
A guide having a guide portion in which a through hole for accommodating and guiding the shaft portion is formed; and a support plate portion for supporting the guide portion;
A switch contact operated by being pushed by the tip of the shaft portion,
Two ribs extending in the axial direction of the shaft portion are formed on the outer peripheral surface of the shaft portion so as to protrude at least in two different directions around the shaft.
A plurality of grooves for slidingly guiding the ribs are formed on the inner peripheral surface of the through hole,
At least one of a guide-side intrusion prevention wall that protrudes and surrounds the guide portion on the support plate portion, or a push-button-side intrusion prevention wall that protrudes and surrounds the shaft portion on the back surface of the key top. A push button switch characterized in that is provided. The pushbutton switch according to claim 1, wherein
A push button switch, wherein both the guide side intrusion prevention wall and the push button side intrusion prevention wall are provided. The pushbutton switch according to claim 2,
The push button switch, wherein the guide side intrusion prevention wall and the push button side intrusion prevention wall are formed alternately. The pushbutton switch according to claim 2,
The pushbutton switch, wherein the guide-side intrusion prevention wall and the pushbutton-side intrusion prevention wall are formed at positions facing each other. The pushbutton switch according to any one of claims 1 to 4,
2. The push button switch according to claim 1, wherein the rib is formed at a position where the rib is 90 [deg.]. The pushbutton switch according to any one of claims 1 to 4,
The push button switch is characterized in that the ribs are three and are formed at intervals of 90 °.

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