JP4380599B2 - Switch device - Google Patents

Description

  The present invention relates to a switch device in which a switch mechanism is housed in an airtight housing.

  2. Description of the Related Art Conventionally, as this type of switch device, an apparatus provided with an operation element that projects from an opening provided in a housing to the outside of the housing and is operated so as to open and close a switch mechanism in the housing is provided.

In the switch device provided with the opening, a gap is formed between the housing and the operation element in the opening, so that water and dust do not enter the housing through the gap. A sealing cap that is hermetically bonded to the periphery of the opening over the entire periphery of the opening and seals the gap is provided (see Patent Document 1). The sealing cap needs to be deformed along with the operation of the operation element so as not to hinder the operation of the operation element, and is preferably made of silicone rubber because it is desirable to have excellent durability and excellent temperature characteristics. There are many things.
JP-A-4-167315 (page 3)

  However, the conventional sealing cap formed of silicone rubber or the like cannot prevent gas permeation, and the gas that has permeated the sealing cap enters the housing through the gap between the housing and the operation element at the opening. There is a possibility of intrusion. Therefore, for example, when this type of switch device is used in an environment where the concentration of corrosive gas is high, there is a problem that the contact of the switch mechanism is corroded by the corrosive gas entering the housing, resulting in poor contact. Arise.

  The present invention has been made in view of the above-described reasons, and an object thereof is to provide a switch device in which gas hardly enters the housing from the outside of the housing.

According to the first aspect of the present invention, there is provided an airtight housing in which the switch mechanism is accommodated, an operating element that protrudes to the outside of the housing through an opening provided in the housing and is operated to open and close the switch mechanism, and a housing A seal that is hermetically joined to the periphery of the opening on the outer side of the opening, seals a gap formed between the housing and the operating element in the opening, and deforms in accordance with the operation of the operating element. And a protective film comprising a thin film formed on at least one surface in a thickness direction of the sealing cap and preventing gas permeation through the sealing cap, the protective film being a surface on which the protective film of the sealing cap is provided There are formed in the most stretched state in the movable range of the operating element, characterized in Rukoto.

According to this configuration, the gap formed between the housing and the operation element in the opening is sealed by the sealing cap, and the gas is not transmitted through the sealing cap by the protective film. It is possible to prevent gas from entering the housing through a gap formed between the housing and the operation element. And since a protective film consists of thin films, it can prevent that gas permeate | transmits a sealing cap, without impairing the performance of sealing cap itself. Further, when forming the protective film, the protective film is formed in a state where the surface of the sealing cap on which the protective film is provided is stretched most within the movable range of the operating element. Regardless, the film thickness of the protective film can be maintained to be equal to or greater than the film thickness at the time of molding, and the effect of preventing the permeation of gas through the sealing cap is reliably exhibited.

  The invention of claim 2 is characterized in that, in the invention of claim 1, the protective film is formed on both surfaces in the thickness direction of the sealing cap.

  According to this structure, there exists an advantage that gas becomes difficult to permeate | transmit a sealing cap rather than forming a protective film only in one surface of the thickness direction of a sealing cap.

  According to a third aspect of the present invention, in the first aspect of the invention, the protective film is formed on one surface having a smaller amount of expansion and contraction when the operation element is operated among the respective surfaces in the thickness direction of the sealing cap. It is characterized by being.

  According to this configuration, since the expansion / contraction amount of the protective film when the operating element is operated is relatively small, there is an advantage that the protective film is hardly deteriorated even if the operating element is operated.

  According to a fourth aspect of the present invention, in the first to third aspects of the present invention, the operation element has an operation surface to which an external force is applied at the time of operation at a distal end protruding from the housing, and the sealing cap The insertion hole is formed to project the tip of the operation element outward, and the periphery of the insertion hole is hermetically joined to the peripheral surface of the operation element over the entire circumference of the insertion hole.

  According to this configuration, since the tip of the operation element having the operation surface protrudes from the sealing cap, the operation element can be operated without touching the sealing cap, and the protective film formed on the sealing cap Has an advantage that it does not easily deteriorate even if the operation element is operated. Further, since the surface area of the sealing cap can be reduced as compared with the case where the entire operation element is covered with the sealing cap, the gas is less likely to enter the housing.

  According to a fifth aspect of the present invention, in the first to fourth aspects of the invention, the protective film is formed by a thin film forming method selected from a vacuum deposition method and a sputtering method.

  According to this configuration, in any switch device using a sealing cap of any shape, it is possible to prevent gas from entering the housing through the opening by providing the protective film on the sealing cap. In addition, since a protective film can be formed on a plurality of sealing caps at the same time, an increase in man-hours when manufacturing a large number of switch devices can be suppressed, leading to cost reduction.

  A sixth aspect of the invention is characterized in that, in the first to fifth aspects of the invention, the sealing cap is made of silicone rubber, and the protective film is made of diamond-like carbon.

  According to the present invention, the gap formed between the housing and the operation element in the opening is sealed by the sealing cap, and gas permeation in the sealing cap is prevented by the protective film. Gas can be prevented from entering the housing through a gap formed between the control member and the operating element. And since a protective film consists of a thin film, there exists an advantage that gas can be prevented from permeate | transmitting a sealing cap, without impairing the performance of sealing cap itself.

  As shown in FIG. 2, the switch device of the present embodiment accommodates the switch mechanism 2 (see FIG. 1A) in a housing 1 formed in a rectangular parallelepiped shape, and has an opening 3 ( The operation element 4 protrudes to the outside of the housing 1 through FIG. In the following, the basic configuration of the switch device will be described first with the vertical and horizontal directions in FIG.

  The housing 1 includes a body 5 formed in a box shape with one side surface (the right end surface in FIG. 2A) opened, and the terminal plates 6 to 8 (FIG. 1) of the switch mechanism 2 from the side surface of the body 5. The switch mechanism 2 is accommodated in such a manner that (see (a)) faces outward, and the sealing agent 10 is filled so as to seal the side face with the lead wires 9 connected to the terminal plates 6 to 8 respectively. To ensure airtightness. The opening 3 opens in a circular shape on the upper surface of the housing 1. Further, the housing 1 is provided with an attachment hole 11 used when the switch device is attached to an electric device or the like.

  As shown in FIG. 1B, the operation element 4 is formed in a columnar shape that is long in the vertical direction according to the shape of the opening 3, and has a gap 12 between the opening 3 and the housing 1. This makes it possible to move straight in the axial direction. Further, grease is applied to the inner peripheral surface of the opening 3 in the housing 1, and friction between the housing 1 and the operation element 4 is reduced. As will be described in detail later, the operation element 4 opens and closes the switch mechanism 2 in the housing 1 when the upper end portion is pushed.

  Here, the flange 13 provided at the lower end portion of the operation element 4 functions as a retainer for the operation element 4 by coming into contact with the peripheral edge of the opening 3 on the inner side surface of the housing 1. In this embodiment, the holding frame 14 that is cylindrical and has the opening 3 penetrating in the axial direction is fitted from above into a through hole 15 that penetrates the upper wall of the body 5. The housing 1 is formed, and the operation element 4 can be inserted into the opening 3 from the inside of the housing 1 when the housing 1 is assembled. The holding frame 14 is configured such that a locking piece 16 provided over the entire circumference of the outer peripheral surface is placed on a step 17 formed on the inner peripheral surface of the through hole 15 so that no gap is generated between the holding frame 14 and the body 5. Is combined with the body 5.

  Further, a sealing cap 18 formed in a bottomed cylindrical shape with a bottom opening from silicone rubber projects the upper end of the operation element 4 from an insertion hole 19 (see FIG. 3A) penetrating the upper wall. The controller 4 is mounted in the form. A fitting groove 20 is formed over the entire circumference of a part of the outer peripheral surface of the operation element 4, and the sealing cap 18 has the insertion hole 19 in a state in which the periphery of the insertion hole 19 is fitted into the fitting groove 20. Are hermetically joined to the operating element 4 over the entire circumference. Further, the lower end portion of the sealing cap 18 is sandwiched between the inner peripheral surface of the through hole 15 and the outer peripheral surface of the holding frame 14 in the body 5 and is ultrasonically welded to the body 5 over the entire periphery of the opening 3. It is airtightly joined. That is, the gap 12 between the housing 1 and the operation element 4 in the opening 3 is sealed by the sealing cap 18.

  As shown in FIG. 3A, an annular concave portion 21 that protrudes downward and an annular convex portion 22 that protrudes upward are formed around the insertion hole 19 on the upper wall of the sealing cap 18. Thus, the cross section passing through the insertion hole 19 and extending in the vertical direction (that is, the cross section shown in FIG. 3A) is meandering in the vertical direction. When the concave portion 21 and the convex portion 22 are provided in this manner, the distance between the outer peripheral edge of the upper wall of the sealing cap 18 and the peripheral edge of the insertion hole 19 is extended, as shown in FIG. Even when the operation element 4 is pushed in, the portion of the sealing cap 18 that has formed the concave portion 21 and the convex portion 22 is stretched, so that the sealing cap 18 itself deforms with little expansion or contraction. Will do. Therefore, the stress applied to the sealing cap 18 with the operation of the operation element 4 can be reduced.

  On the other hand, as shown in FIG. 1A, the switch mechanism 2 includes a pair of terminal plates 6 and 7 that are fixed in positions facing each other in the vertical direction, and a tip portion between the terminal plates 6 and 7. And a terminal plate 8 connected to the movable element 23 inserted through a support plate 24 described later. A normally closed contact 25 and a normally open contact 26 are respectively provided on the opposing surfaces of the pair of terminal plates 6 and 7, and correspond to the normally closed contact 25 and the normally open contact 26 at the tip of the mover 23. A common contact point 27 is provided at the site to be operated. The mover 23 is rotatably supported using a connecting portion with the support plate 24 as a fulcrum so that the common contact 27 can be contacted and separated from the normally closed contact 25 and the normally open contact 26, respectively. The support plate 24 is rotatable about the connecting portion with the terminal plate 8 as a fulcrum so that the base end portion of the mover 23 (that is, the connecting portion of the mover 23 to the support plate 24) is movable in the vertical direction. Supported. Furthermore, the mover 23 is spring-springed in a direction in which the common contact 27 is brought into contact with either the normally closed contact 25 or the normally open contact 26 by a reversing spring 28 formed of a leaf spring that generates a spring force with the terminal plate 8. Be energized. The switch mechanism 2 configured as described above is disposed at a position where the base end portion of the movable element 23 is brought into contact with the lower end surface of the operation element 4.

  Hereinafter, the operation of the switch device of this embodiment will be briefly described. First, as shown in FIG. 1A, in a state where the flange portion 13 of the operation element 4 is in contact with the lower surface of the holding frame 14 (hereinafter referred to as an initial state), the mover 23 normally closes the common contact 27. The terminal plate 6 and the terminal plate 8 are electrically connected to each other by being biased by the reversing spring 28 in the direction of contact with the contact 25. On the other hand, when the operating element 4 is pushed in, the movable element 23 is pressed by the operating element 4 and moves downward. Here, when the mover 23 is pushed to a predetermined position, the direction in which the reversing spring 28 biases the mover 23 is reversed, and the common contact 27 instantaneously moves from the normally closed contact 25 side to the normally open contact 26 side. Moving. That is, when the operating element 4 is pushed in and the lower end portion of the support plate 24 is in contact with the inner surface of the housing 1 (hereinafter referred to as an operating state) as shown in FIG. The common contact 27 is spring-biased by the reversing spring 28 in a direction in which the common contact 27 is brought into contact with the normally open contact 26, and the terminal plate 7 and the terminal plate 8 are conducted. When the pressing of the operation element 4 is stopped, the movable element 23 and the operation element 4 are returned to the initial state by the spring force of the reversing spring 28.

  By the way, the switch device according to the present embodiment employs the configuration described below in addition to the basic configuration described above, so that the gas passes through the gap 12 between the housing 1 and the operation element 4 in the opening 3 and enters the housing 1. To prevent intrusion.

  That is, in this embodiment, as shown in FIG. 3, protective films 29 that prevent gas permeation through the sealing cap 18 are formed on both surfaces of the sealing cap 18 in the thickness direction. The protective film 29 is a thin film made of diamond-like carbon (DLC), and is formed with a film thickness (for example, several to several thousand mm) sufficiently smaller than the thickness dimension of the sealing cap 28. Thereby, it is possible to prevent gas from entering the housing 1 through the gap 12 sealed with the sealing cap 18. As a result, even when the switch device is used in an environment where the concentration of corrosive gas is high, the corrosive gas does not enter the housing 1, and the contact of the switch mechanism 2 is corroded. Can be prevented. Diamond-like carbon is known as amorphous carbon having intermediate characteristics between diamond and graphite.

  Here, since the upper surface serving as an operation surface to which external force is applied during operation in the operation element 4 is exposed from the sealing cap 18, the operation element 4 can be operated without touching the sealing cap 18. The protective film 29 formed on the cap 18 is hardly deteriorated even when the operation element 4 is operated. In addition, since the performance of the sealing cap 18 itself is not impaired by making the protective film 29 a thin film, the sealing cap 18 is operated in the present embodiment in which the sealing cap 18 is formed of silicone rubber. The performance of the sealing cap 18 having excellent durability and excellent temperature characteristics is maintained as well as being deformed in accordance with the operation of the child 4.

  The protective film 29 described above is formed by a thin film forming method selected from a vacuum vapor deposition method and a sputtering method, so that not only the sealing cap 18 having the shape described above but also any shape of the sealing cap 18 can be obtained. In contrast, the protective film 29 can be formed. Further, as shown in FIG. 4, when a protective film 29 is formed by the above-described thin film forming method on a rubber sheet 30 in which a plurality of sealing caps 18 are integrally formed on one surface, a plurality of the rubber sheets 30 are formed. Since the protective film 29 can be simultaneously formed on the sealing cap 18, an increase in man-hours due to the formation of the protective film 29 when manufacturing a large number of switch devices can be suppressed, leading to a reduction in cost. . In addition, since the grease is applied to the inner peripheral surface of the opening 3 as described above, even if a part of the protective film 29 may be peeled off from the sealing cap 18, the peeled protective film The pieces of 29 adhere to the grease, and the pieces of the protective film 29 do not enter the housing 1 through the gap 12.

  In the present embodiment, the protective film 29 is formed on both surfaces of the sealing cap 18 in the thickness direction. However, the protective film 29 is formed on any one of the surfaces in the thickness direction of the sealing cap 18. Also good. In this case, as the surface on which the protective film 29 is formed, it is desirable to select one surface of the surfaces in the thickness direction of the sealing cap 18 that has the smaller expansion / contraction amount when the operation element 4 is operated. When forming the protective film 29, it is desirable to form the protective film 29 in a state where the surface of the sealing cap 18 on which the protective film 29 is provided is most stretched within the movable range of the operation element 4. Thus, the film thickness of the protective film 29 can be maintained to be equal to or greater than the film thickness at the time of molding regardless of the operation of the operation element 4, and the effect of preventing the permeation of gas through the sealing cap 18 can be reliably achieved. .

  Further, the structure in which the entire operation element 4 is covered with the sealing cap 18 without providing the insertion hole 19 in the sealing cap 18, and the operation element 4 is operated through the sealing cap 18 as described above. Further, by forming the protective film 29 on both surfaces (or one surface) of the sealing cap 18 in the thickness direction, it is possible to prevent the gas from passing through the sealing cap 18 and prevent the gas from entering the housing 1. .

  FIG. 5 shows an example of a switch device in which a protective film 29 is formed on the sealing cap 18 and having a basic configuration different from that of the above-described switch device. However, the protective film 29 is not particularly shown in FIG.

  Hereinafter, the operation of the switch device of FIG. 5 will be briefly described. When the operating element 4 is pushed in, a movable spring 23 ′ composed of a leaf spring provided in place of the movable element 23 and the support plate 24 in FIG. 1A uses the base end portion supported by the terminal plate 8 as a fulcrum. It is pressed by the operating element 4 and moves downward. Here, when the movable spring 23 ′ is pushed to a predetermined position, the direction in which the reversing spring 28 biases the movable spring 23 ′ is reversed, and the common contact 27 provided at the tip of the movable spring 23 ′ is normally closed. It moves instantaneously from the contact 25 side to the normally open contact 26 side. In addition, in the housing 1 shown in FIG. 5, the structure which the opening part 3 was penetrated by the body 5 itself without providing the holding frame 14 (refer FIG. 1) is employ | adopted, and the lower end part of the sealing cap 18 is the following. The body 5 is hermetically joined to the body 5 by being inserted into a joining groove 31 that is recessed around the opening 3 on the upper surface of the body 5 over the entire circumference of the opening 3.

  By the way, in the present embodiment, a so-called micro switch in which the direction in which the reversing spring 28 biases the movable element 23 (or the movable spring 23 ′) in accordance with the pressing operation of the operating element 4 is reversed and the switch mechanism 2 opens and closes is used as a switching device. Although illustrated, the switch device in which the present invention is adopted is not limited to a micro switch. Further, the present invention is not limited to the push button type switch device in which the operation element 4 is pushed. For example, as shown in FIG. 6, the switch mechanism 2 is opened and closed by tilting the operation element 4 in the left-right direction. The present invention can also be applied to a lever type switch device. However, the protective film 29 is not particularly shown in FIG. In the configuration shown in FIG. 6, when the switch device is formed to have the same size as the push button type switch device, the gap 12 formed between the housing 1 and the operation element 4 in the opening 3 is a push button type switch device. Although it is larger than the switch device, in the present invention, gas is prevented from permeating through the sealing cap 18, so that gas can enter the housing 1 through the gap 12 regardless of the size of the gap 12. Can be prevented.

  The material of the sealing cap 18 and the material of the protective film 29 are not limited to the combination of silicone rubber and diamond-like carbon. For example, the sealing cap 18 may be formed from a synthetic rubber other than silicone rubber.

The structure of embodiment of this invention is shown, (a) is a partially broken sectional view of an initial state, (b) is a sectional view of the principal part of (a), (c) is a partially broken sectional view of an operating state, (D) is sectional drawing of the principal part of (c). The external appearance is shown, (a) is a front view, (b) is a side view. The sealing cap used for the above is shown, (a) is a sectional view, (b) is a sectional view of the main part. The rubber sheet used at the time of manufacture same as the above is shown, (a) is a top view and (b) is a front view. It is sectional drawing which shows the other example same as the above. The main part of the lever type switch device is shown, (a) is a cross-sectional view, (b) is a cross-sectional view with the operating element tilted to the left, and (c) is a state with the operating element tilted to the right. FIG.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Housing 2 Switch mechanism 3 Opening part 4 Operator 12 Gap | interval 18 Sealing cap 19 Insertion hole 29 Protective film

Claims (6)

An airtight housing in which the switch mechanism is housed, an operator projecting to the outside of the housing through an opening provided in the housing and operated to open and close the switch mechanism, and an opening on the outer surface of the housing A sealing cap that is hermetically bonded to the surroundings of the entire periphery of the opening, seals a gap formed between the housing and the operating element in the opening, and is deformed in accordance with the operation of the operating element; and a sealing cap And a protective film that prevents gas permeation through the sealing cap. The protective film has a surface on which the protective film is provided within the movable range of the operation element. in it is formed in the most stretched state switching device according to claim Rukoto.   The switch device according to claim 1, wherein the protective film is formed on both surfaces of the sealing cap in the thickness direction.   2. The switch according to claim 1, wherein the protective film is formed on one surface of the surfaces in the thickness direction of the sealing cap that has a smaller amount of expansion and contraction when the operation element is operated. apparatus.   The operation element has an operation surface to which an external force is applied at the time of operation at a distal end portion projecting to the outside of the housing, and the sealing cap has an insertion hole for projecting the distal end portion of the operation element outward. The switch device according to any one of claims 1 to 3, wherein the periphery of the insertion hole is hermetically joined to the peripheral surface of the operation element over the entire circumference of the insertion hole.   The switch device according to any one of claims 1 to 4, wherein the protective film is formed by a thin film forming method selected from a vacuum deposition method and a sputtering method.   6. The switch device according to claim 1, wherein the sealing cap is made of silicone rubber, and the protective film is made of diamond-like carbon.

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