JP7331389B2 - Manufacturing method for airtight structure - Google Patents

Description

The present invention relates to a method for manufacturing an airtight structure and an airtight structure.

Solving social problems using IoT (Internet of Things) is spreading, and in various scenes/environments, motion information, biological information, location information, climate information, chemical information, etc. are required. As a result, the sensing devices used to obtain the desired information have a wide variety of requirements in terms of function, shape, and required quantity, and production sites are required to respond quickly to a wide variety of products.

On the other hand, the environment in which the equipment is installed is also diverse, and it is required to continue to operate even in environments exposed to wind and rain, or in environments where oil and chemicals are splashed on it. For this reason, it is necessary to provide airtightness so that water, dust, chemicals, etc., will not enter the inside of the device and cause the device to malfunction.

In this way, as a method that can easily achieve airtightness for a wide variety of devices, structural design is easy, production automation and multi-product compatibility are high, and miniaturization needs can be met. Expectations are high for the realization of a structure/construction method using a liquid sealing material that can

In the past, electronic devices used in environments such as those exposed to water and dust, such as those described above, were mainly structured to be sealed with preformed packings or gaskets. However, in recent years, in order to meet the needs for automated assembly and miniaturization of equipment, a method using a liquid sealing material instead of packing has been adopted in many cases.

There are two major ways to use such a liquid sealing material. One is a method of applying a sealing material to a target portion of one of the housings, curing the applied sealing material to form a sealing portion, and compressing the sealing portion between the housings to obtain an airtight seal. This method is called CIPG (Cured In Place Gasket, hereinafter referred to as CIPG), and is hereinafter referred to as CIPG in this specification. In the CIPG, the sealing material is compressed to obtain airtightness. Therefore, if the height of the sealing material varies, uniform compression cannot be obtained when the sealing material is compressed, resulting in deterioration of airtightness. Therefore, in CIPG, it is necessary to control the application height of the sealing material with high precision. A technique for solving this problem is disclosed in Patent Document 1, for example. In this technique, a thermosetting silicone rubber is first cast in a bead shape in the longitudinal direction, and then the concave surface of a heated concave mold is brought into contact with the surface of the thermosetting silicone rubber to cure it. . Thereby, the height of the sealing material can be controlled with high accuracy.

Another method of using the liquid sealing material is to apply the liquid sealing material to the target location and bond the housings together before curing. This method is called FIPG (Formed In Place Gasket), and is hereinafter referred to as FIPG in this specification. In the FIPG, the housings are glued or glued together. In the FIPG, since the sealing material is in a liquid state when the housings are overlapped, high-precision height control as in the CIPG is not required. Moreover, there is an advantage that airtightness can be ensured without applying compression to the sealing material. The above two advantages are extremely useful in electronic equipment, for which there is a strong demand for miniaturization in recent years. An example of a method for waterproofing a small portable electronic device using FIPG is disclosed in Patent Document 2.

JP-A-05-246456 JP 2011-086817 A

However, in the technique disclosed in Patent Document 1, a molding die is used to control the height of the sealing material, and there is a problem that a molding die must be prepared for each product type. In addition, the FIPG as disclosed in Patent Document 2 has a problem that it cannot be easily disassembled because the housings are adhered or adhered to each other. Moreover, even if it can be disassembled successfully, it is difficult to reassemble because the sealing material cannot be reused.

SUMMARY OF THE INVENTION It is an object of the present invention to provide a method of manufacturing an airtight structure that can easily form a detachable and highly reliable airtight structure.

In order to solve the above problems, in the method of manufacturing an airtight structure of the present invention, first, a liquid sealing material is applied to the first sealing surface of the first housing 1 . Next, a second housing having a second sealing surface having a shape facing the first sealing surface is brought close. Then, the second sealing surface is brought into close contact with the liquid sealing material so that the first sealing surface and the second sealing surface face each other. In this state, the sealing material is cured. Next, a force is applied in a direction in which the first sealing surface and the second sealing surface approach each other, compressing the hardened sealing material. In this state, the positional relationship between the first housing and the second housing is fixed by compression fixing means.

An effect of the present invention is to provide a method for manufacturing an airtight structure that can easily form a detachable and highly reliable airtight structure.

It is a cross-sectional schematic diagram which shows the manufacturing method of the airtight structure of 1st Embodiment. It is a perspective view which shows the airtight structure of 2nd Embodiment. It is a perspective view which shows the disassembled state of the airtight structure of 2nd Embodiment. FIG. 11 is a perspective view showing a method of applying a sealing material according to the second embodiment; It is a partial cross-sectional view showing the airtight structure of the second embodiment. It is a sectional view showing the composition near the seal part of a 2nd embodiment. It is sectional drawing which shows a part of manufacturing method of the airtight structure of 2nd Embodiment. It is a sectional view showing another part of the manufacturing method of the airtight structure of the second embodiment. FIG. 11 is a cross-sectional view showing a seal portion after application of a sealing material according to the second embodiment; FIG. 11 is a cross-sectional view showing the sealing portion when the sealing material of the second embodiment is cured; FIG. 10 is a cross-sectional view showing the sealing portion when the sealing material is compressed according to the second embodiment; FIG. 8 is a cross-sectional view showing the seal portion when the second embodiment is disassembled; It is sectional drawing which shows the dimension of each part regarding the manufacturing method of 2nd Embodiment. It is sectional drawing which shows a part of manufacturing method of the airtight structure of 3rd Embodiment. It is a sectional view showing another part of the manufacturing method of the airtight structure of the third embodiment. It is a cross-sectional view showing still another part of the manufacturing method of the airtight structure of the third embodiment. It is sectional drawing which shows a part of manufacturing method of the airtight structure of 4th Embodiment. It is a cross-sectional view showing another part of the manufacturing method of the airtight structure of the fourth embodiment. It is sectional drawing which shows another part of the manufacturing method of the airtight structure of 4th Embodiment.

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. However, the embodiments described below are technically preferable for carrying out the present invention, but the scope of the invention is not limited to the following. In addition, the same number may be attached|subjected to the same component of each drawing, and description may be abbreviate|omitted.

(First embodiment)
FIG. 1 is a schematic cross-sectional view showing a method for manufacturing an airtight structure according to the first embodiment. In the airtight structure of this embodiment, a closed space is formed by sandwiching a sealing material between the first housing and the second housing.

Method for Manufacturing the Airtight Structure of the Present Embodiment First, as shown in FIG. Although not shown, the first sealing surface 1a and the applied liquid sealing material 2 form a closed curve.

Next, a second housing 3 having a second sealing surface 3a having a shape facing the first sealing surface 1a is brought close. Then, as shown in FIG. 1B, the second sealing surface 3a is brought into close contact with the liquid sealing material 2 so that the first sealing surface 1a and the second sealing surface 3a face each other. In this state, the sealing material 2 is cured.

Next, as shown in FIG. 1(c), a force is applied in a direction in which the first sealing surface 1a and the second sealing surface 3a approach each other to compress the hardened sealing material 2. Then, as shown in FIG. In this state, the positional relationship between the first housing 1 and the second housing 3 is fixed by the compression fixing means 4 . In addition, in FIG.1(c), the compression fixing means 4 is drawn so that it may have a U-shaped cross section, but the compression fixing method is arbitrary and it is not restricted to this. For example, it may be screwed or locked with a claw. According to the above process, similarly to the FIPG, it is possible to fill the sealing material without gaps between the housings without controlling the application of the sealing material with high accuracy. Further, by compressing the sealing material after curing, the reliability of the seal can be improved.

If the second sealing surface 3a does not have adhesion to the sealing material 2, the first housing 1 and the second housing 3 can be easily separated by releasing the fixation. . Alternatively, the first sealing surface 1a may not have adhesion to the sealing material 2. FIG.

As described above, according to the present embodiment, a detachable and highly reliable airtight structure can be easily formed.

(Second embodiment)
FIG. 2 is a perspective view of the airtight device 100 of this embodiment. The base housing 10 and the cover housing 20 are fixed with screws 30 . Although not shown in FIG. 2, a sealing material seals between the base housing 10 and the cover housing 20 to form an airtight structure in which the space surrounded by the two housings is airtight. A cover housing 20 is provided with a screw hole 21. - 特許庁

FIG. 3 is an exploded view of the airtight device 100. FIG. It is a structure in which a substantially box-shaped base housing 10 and a substantially lid-shaped cover housing 20 are fastened and fixed with screws 30 . The base housing 10 has a screw hole 11 for fastening and fixing and a depression 12 for positioning during assembly, and the cover housing 20 has a through hole 22 through which the screw 30 is passed, and an empty screw hole 21 facing the depression 12. have A sealing material 40 is interposed between the two housings, and the sealing material 40 is sandwiched between the two housings and compressed and fixed with screws 30 to keep the inside of the device airtight.

FIG. 4 is a perspective view schematically showing how the sealing material 40 is applied. The sealing material 40 is applied along a path surrounding the space inside the base housing 10 . The coating is formed by drawing a predetermined trajectory along the sealing surface 13 while discharging the sealing material 40 in a syringe (not shown) from the nozzle 200 by air pressure. For the sealing material 40, for example, a resin that becomes a rubber elastic body when hardened can be used. Specifically, for example, a liquid silicone-based sealing material can be used.

FIG. 5 is a partial cross-sectional view of the airtight device 100 assembled in an airtight state (FIG. 2). FIG. 6 is an enlarged view of part A in FIG. 5, and is a diagram schematically showing the fastening portion of the screw 30 and the cross-sectional portion of the sealing material 40. As shown in FIG. The cover housing 20 is fastened to the base housing 10 with screws 30 . The sealing material 40 is sandwiched and crushed between the sealing surface 23 of the cover housing 20 and the sealing surface 13 of the base housing 10 (B section).

7 and 8 are diagrams for explaining the manufacturing method of this embodiment. As shown in FIG. 7, first, a fixing screw 30 is screwed from the front surface of the cover housing 20 into the screw hole 22 provided separately from the installation location of the through hole 21, and the back surface of the cover is screwed by a predetermined length t. protrude from According to FIG. 7, the protrusions are fitted into recesses 12 of depth tg provided in the opposing base housings 10 to determine the position in the plane direction and to set the gap between the housings to be g. The position of the cover housing 20 in the height direction is determined. At this time, the sealing member 40 is kept in contact with the sealing surface 23 of the cover housing 20 over the entire circumference. After curing the sealing material 40 in this state, the screw 30 is pulled out and screwed into the screw hole 11 through the fixing through hole 21 as shown in FIG. As a result, the cover housing 20 and the base housing 10 abut each other, the hardened sealing material 40 is compressed, the base housing 10 and the cover housing 20 are fixed at the final assembly position, and the airtightness of the airtight device 100 is improved. Complete.

Next, a specific example of this embodiment will be described. FIG. 9 is an enlarged view of part C in FIG. 7, and is a cross section of the vicinity of the sealing material 40 before assembly. Here, the applied height h of the sealing material 40 was set to 1.7 mm. The sealing surface 23 of the opposing cover housing 20 has a depth d of 0.9 mm so that the thickness of the sealing material at the final assembly position is h2=0.9 mm (FIG. 11, the amount of compression is p2=0.4 mm). The groove bottom was 9 mm. The sealing surface 13 on the base housing 10 side to which the sealing material 40 is applied is on the rib with a width w=2.4 mm. This is because by defining the application width of the sealing material 40, variations in application shape and application height can be suppressed, and when the sealing material 40 is compressed, the sealing material 40 can be easily deformed by escaping to both sides. (Fig. 11).

FIG. 10 is an enlarged view of part D in FIG. 8, showing a cross section near the sealing material when the gap between the housings is g=0.4 mm. At this point, the height of the sealing material 40 is h1=1.3 mm (the crushing amount p1=0.4 mm). Since the sealing material 40 is in an uncured state, it is in a state of flow deformation following the contact surface, and no repulsive force is generated. When the sealing material 40 is cured in this state, it becomes a rubber elastic body uniformly in contact with the sealing surface 23 of the cover housing 20 over the entire circumference.

FIG. 11 is an enlarged view of part B in FIG. 6, showing a completed state in which the sealing material 40 is screwed to the final assembly position after hardening. This is a state in which p2=0.4 mm is further pushed in from the previous state (g≈0, the final assembly position where the airtight device 10 and the base housing collide), and the thickness of the sealing material 40 is h2=0.9 mm, which is about 30 mm. % compressed. Since it is hardened, the deformation of the sealing material 40 is elastic deformation, and the sealing material 40 is in a close contact state with a repulsive force.

FIG. 12 is a cross section near the seal member in a state where the cover housing 20 is removed for repair or the like after assembly. When the cover housing 20 and the base housing 10 are fastened and fixed, the sealing material 40 is in a state of compressing the elastic body. For this reason. When the cover housing 20 is separated from the base housing 10, the sealing material 40 is released from the compressed state and returns to the state when it was cured (height h1≈1.3 mm of the sealing material 40). Therefore, when reassembled, it is similarly compressed and a repulsive force is obtained, so airtightness can be reproduced.

Here, a method for deriving the coating height h, the gap g, and the seal surface groove depth d will be described.
As shown in FIG. 13, the coating height can be written as h=p1+p2+h2. Also, there is a relationship of p2=g and h2=d.

Here, if c is the amount of warp of the sealing surface 23 and the sealing surface 13, it is designed so that p1≧c. This is because the sealing member 40 must always be in contact with the airtight device 10 without interruption over the entire circumference when assembled with the gap g provided.

Also, it is designed to satisfy h2≧2c. This is because if the thickness h2 of the sealing material 40 at the final assembly position does not sufficiently exceed the amount of warp c, the portion where the seal gap is narrowed by the warp cannot be fully compressed. If a predetermined compressibility cannot be obtained as a whole, there is a possibility that desired airtightness cannot be obtained.

Assuming that the compressibility of the sealing material 40 at the final assembly position is s, the relationship is p2:h2=s:1-s. It should be noted that the compression rate should be about 5 to 40%.
From the above,
h = p1 + p2 + h2
=c + h2 x s/(1-s) + h2
The above numerical values were calculated by setting h2=0.9 (≧2c) and compression rate 30% when the amount of warp c=0.4 mm. i.e.
h = 0.4 + 0.4 (0.386 rounded up) + 0.9
= 1.7mm
Further, the gap g=p2=0.4 mm (0.386 is rounded up), and the seal surface groove depth d=0.9 mm.

The sealing surface 23 is preferably coated so that the sealing material 40 can be easily peeled off. For example, there are methods such as applying a fluorine-based release agent and plating with good release properties. After applying the sealing material 40, the adhesive force may be reduced by leaving the surface to the extent that it begins to harden or until a thin hardened film is formed before assembling.

It is preferable that the sealing surface 13 of the base housing 10 has increased adhesion to the sealing material 40 . For this purpose, for example, roughening by etching or sandblasting, providing an anchor shape (not shown) that physically fits, or applying a primer to increase adhesion can be performed. To leave the sealing material 40 on the side of the base housing 10 at the time of disassembly by increasing the adhesive strength between the sealing material 40 and the base housing 10 and decreasing the adhesive strength between the sealing material 40 and the cover housing 20. - 特許庁can be done.

As described above, according to the present embodiment, a highly reliable airtight structure can be formed without precisely controlling the application height of the sealing material. In addition, it is possible to obtain an airtight device that is easily disassembled and has high airtightness reliability even after reassembly.

(Third Embodiment)
14-16 show a second embodiment of the invention. As shown in FIG. 14, the boss 50 is press-fitted into the fitting hole 24 in the cover housing 20 with a force that does not come off due to the weight of the cover housing 20 and that the boss 50 can be pulled out by the screw fastening force. The boss 50 protrudes from the rear surface of the cover so as to provide a housing gap g when assembled. As the cover housing 20 approaches the base housing 10, as shown in FIG. The interbody gap is controlled to g. At this time, the sealing material 40 is uniformly in contact with the sealing surface 23 of the cover housing 20 over the entire circumference. The sealing material 40 is cured in this state. Next, as shown in FIG. 16, the screw 30 is screwed into the front surface screw hole 11 of the cover housing 20 and tightened. Then, the hardened sealing material 40 is compressed, the boss 50 is pulled out by the fastening force, and the cover housing 20 abuts against the base housing 10 to reach the final assembly position, completing the airtightness of the device.

As described above, according to the present embodiment, it is possible to obtain an airtight device similar to that of the second embodiment while reducing the number of man-hours required for attaching and detaching screws.

(Fourth embodiment)
17-19 show a fourth embodiment of the invention. Similar screw holes 25 are provided in the cover housing 20 at positions facing the fixing screw holes 11 on the base housing 10 side. At the stage where the sealing material 40 is applied to the sealing surface 13 of the base housing 10, as shown in FIG. is screwed so that the tip protrudes from the The projection amount of the screw 31 is set so that the housing gap g can be obtained after the screw 31 is fitted into the screw hole 11 of the base housing when assembled. Next, when the cover housing 20 is brought closer to the base housing 10, as shown in FIG. At the same time, the gap between the housings is controlled to g. At this time, the sealing material 40 is uniformly in contact with the sealing surface 23 of the cover housing 20 over the entire circumference. The sealing material 40 is cured in this state. Next, as shown in FIG. 19, when the screw 31 is tightened into the screw hole 11, the cylindrical portion 31a does not interfere with the screw hole 25, and the final assembly position is reached where the cover housing 20 and the base housing 10 abut each other. , the airtightness of the device is completed.

As described above, according to this embodiment, it is possible to obtain an airtight device similar to that of the second and third embodiments while reducing the number of parts.

The present invention has been described above using the above-described embodiments as exemplary examples. However, the invention is not limited to the above embodiments. That is, within the scope of the present invention, various aspects that can be understood by those skilled in the art can be applied to the present invention.

1 first casing 2, 40 sealing material 3 second casing 4 compression fixing means 10 base casing 11, 25 screw hole 12 recess 13, 23 sealing surface 20 cover casing 21 screw hole 22 through hole 24 fitting Matching hole 30, 31 Screw 50 Boss 100 Airtight device

Claims (6)

applying a sealing material to the first sealing surface of the first housing;
bringing the second sealing surface of a second housing having a second sealing surface facing the first sealing surface into close contact with the sealing material;
curing the sealing material;
A position of the first housing and the second housing in a state in which pressure is applied in a direction in which the first housing and the second housing approach each other, and the hardened sealing material is compressed. fix the relationship
A method of manufacturing an airtight structure, comprising: maintaining a gap between the first housing and the second housing at a predetermined value when the sealing material is cured. 2. The method for manufacturing an airtight structure according to claim 1, wherein the distance between the first housing and the second housing is reduced by fixing means. After curing the sealing material,
3. The method for manufacturing an airtight structure according to claim 1, wherein the first housing and the second housing are brought into close contact with each other. Adjusting the gap between the first housing and the second housing,
4. The method for manufacturing an airtight structure according to any one of claims 1 to 3 , wherein a screw screwed into at least one of said first housing and said second housing is rotated. abutting the tip of the screw against one of the first housing and the second housing where the screw is not threaded;
5. The method of manufacturing an airtight structure according to claim 4, further comprising: adjusting a gap between the first housing and the second housing to a predetermined value. Either one of the sealing material and the first sealing surface or the second sealing surface is adhesive, and the other is non-adhesive.
The method for manufacturing an airtight structure according to any one of claims 1 to 5 , characterized in that:

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