airtight structure

Abstract

To provide an airtight structure which can maintain airtightness over a long period.SOLUTION: An airtight structure according to the disclosure includes: a case 1 in which a through hole 12 is provided at a wall part (a side wall 11); a cylindrical body 2 having a flange 22 and penetrating through the through hole 12 in a manner that the flange 22 faces an outer surface of the wall part; and a packing 3 disposed between the outer surface and the flange 22 in an airtight manner. The airtight structure includes: a support plate 4 through which the cylindrical body 2 penetrates and which sandwiches the flange 22 with the outer surface to support the cylindrical body 2; and a buffer member 5 which is disposed between the support plate 4 and the flange 22 and covers the packing 3 to shield light.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] The present disclosure relates to an airtight structure.

Background Art

[0002] Conventionally, an airtight structure in which a cylindrical body penetrates the wall portion of a case airtightly has been used. In the switch described in Patent Document 1, a bushing, which is a cylindrical body, penetrates the wall portion of the case airtightly.

Prior Art Document

Patent Document

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] The cylindrical body penetrates through a through-hole provided in the wall portion of the case. When the cylindrical body has a flange and the flange is arranged so as to face the outer surface of the wall portion of the case, a packing may be interposed airtightly between the outer surface of the wall portion of the case and the flange. Due to the interposition of the packing, it is possible to prevent gas from entering and leaving the inside and outside of the case through the gap between the case and the cylindrical body. However, especially when the case is exposed to direct sunlight, the packing is liable to deteriorate by receiving ultraviolet rays, so it is difficult to maintain airtightness over a long period.

[0005] An object of the present disclosure is to provide an airtight structure capable of maintaining airtightness over a long period.

Means for Solving the Problems

[0006] The airtight structure according to this disclosure comprises a case with a through hole in its wall, a cylindrical body having a flange which penetrates the through hole with the flange facing the outer surface of the wall, and a packing which is airtightly interposed between the outer surface and the flange, wherein the airtight structure comprises a support plate through which the cylindrical body is passed and which supports the cylindrical body by sandwiching the flange between itself and the outer surface, and a buffer member interposed between the support plate and the flange and which covers the packing to block light. The airtight structure according to this disclosure comprises a case with a through hole in its wall, a cylindrical body having a flange which penetrates the through hole with the flange facing the outer surface of the wall, and a packing which is airtightly interposed between the outer surface and the flange, wherein the structure further comprises a support plate through which the cylindrical body is penetrated and which supports the cylindrical body by sandwiching the flange between itself and the outer surface, and a buffer member interposed between the support plate and the flange and covering the packing to block light, wherein the wall extends vertically, a gap is formed surrounded by the outer surface, the flange and the packing, the buffer member covers the gap, and a drain port for discharging liquid that has entered the gap is provided at the lower part of the portion of the buffer member that covers the gap. The airtight structure according to this disclosure comprises a case with a through hole in its wall, a cylindrical body having a flange which penetrates the through hole with the flange facing the outer surface of the wall, and a packing which is airtightly interposed between the outer surface and the flange, wherein the structure comprises a support plate through which the cylindrical body passes and which supports the cylindrical body by sandwiching the flange between itself and the outer surface, and a buffer member interposed between the support plate and the flange and which covers the packing and shields light, wherein the buffer member is interposed between the support plate and the flange and has a buffer portion through which the cylindrical body passes, a light-shielding portion whose inner circumferential surface faces the outer circumferential surface of the flange at an appropriate distance apart, extending from the outer circumferential surface of the buffer portion toward the outer surface and covering the packing, and an extension portion extending along the outer surface toward the packing from the tip of the light-shielding portion, and the packing is integrally provided at the tip of the extension portion. The airtight structure according to this disclosure comprises a case with a through hole in its wall, a cylindrical body having a flange which penetrates the through hole with the flange facing the outer surface of the wall, and a packing which is airtightly interposed between the outer surface and the flange, wherein the structure comprises a support plate through which the cylindrical body passes and which supports the cylindrical body by sandwiching the flange between itself and the outer surface, and a buffer member interposed between the support plate and the flange and which covers the packing to shield from light, wherein a light-shielding piece extends from the periphery of the support plate toward the outer surface, covering at least a part of the buffer member, a gap is provided between the outer surface and the tip of the light-shielding piece, and the packing is positioned opposite the gap. The airtight structure according to this disclosure comprises a case having a through hole in its wall, a cylindrical body having a flange which penetrates the through hole with the flange facing the outer surface of the wall, and a packing which is airtightly interposed between the outer surface and the flange, wherein the structure comprises a support plate through which the cylindrical body passes and which supports the cylindrical body by sandwiching the flange between itself and the outer surface, and a buffer member interposed between the support plate and the flange which covers the packing and shields light, wherein the buffer member is separate from the packing, and the buffer member is interposed between the support plate and the flange and integrally comprises a buffer portion through which the cylindrical body passes, and a light-shielding portion extending from the outer circumference of the buffer portion so as to contact the outer surface and cover the packing.

[0007] In this disclosure, a through-hole is provided in the wall of the case, and a cylindrical body passes through the through-hole. The cylindrical body has a flange, which faces the outer surface of the wall. A packing is airtightly interposed between the outer surface of the case wall and the flange, so that gas does not enter or leave the case through the gap between the case and the cylindrical body. The cylindrical body penetrates the support plate. The cylindrical body is supported by a flange sandwiched between the support plate and the outer surface of the wall. A cushioning member is interposed between the support plate and the flange, and a packing is interposed between the wall of the case and the flange, so deformation or damage to the flange due to external forces from the support plate and the wall of the case can be prevented.

[0008] The packing is covered and shielded from light by a cushioning material. Therefore, the packing is prevented from being exposed to ultraviolet rays. Consequently, deterioration of the packing can be prevented over a long period, and airtightness can be maintained over a long period. Moreover, since there is no need for a separate material to cover and shield the packing from light, the number of parts can be reduced.

[0009] The airtight structure according to this disclosure is such that the buffer member is interposed between the support plate and the flange, and comprises a buffer portion through which the cylindrical body passes, and extends from the outer circumference of the buffer portion toward the outer surface, It is characterized by having a light-shielding portion that covers the packing and a light-shielding portion that are integrally connected to each other.

[0010] In this disclosure, the cushioning member has a cushioning portion and a light-shielding portion integrally with each other. The cushioning portion is interposed between the support plate and the flange, and a cylindrical body penetrates the inside of the cushioning portion. The light-shielding portion extends from the outer circumference of the cushioning portion toward the outer surface of the case wall, covering the packing and shielding it from light. In other words, the shape of the cushioning member is simple.

[0011] The airtight structure according to this disclosure is characterized in that the wall portion extends vertically, a gap is formed between the outer surface, the flange, and the packing, the buffer member covers the gap, and a drain port for discharging liquid that has entered the gap is provided at the lower part of the portion of the buffer member that covers the gap.

[0012] In this disclosure, a gap is formed between the outer surface of the case wall, the flange, and the packing, and the cushioning member covers this gap. Since the case walls extend vertically, there is a risk that liquid (rainwater, dew, etc.) may enter this gap by running along the outer surface of the walls. A drainage port is provided at the bottom of the part of the buffer member that covers this gap. In other words, there is a drainage port on the lower side of this gap. Therefore, any liquid that enters this gap will be discharged through the drainage port. Since the drain port is located at the bottom of the buffer material, direct exposure of the packing to ultraviolet rays through the drain port is suppressed.

[0013] The airtight structure according to this disclosure is characterized in that the packing and the cushioning member are provided integrally with each other.

[0014] In this disclosure, since the packing and the cushioning member are integrated with each other, the number of parts can be further reduced.

[0015] The airtight structure according to this disclosure is characterized in that the cushioning member is interposed between the support plate and the flange, and integrally comprises a cushioning portion through which the cylindrical body passes, a light-shielding portion whose inner circumferential surface faces the outer circumferential surface of the flange at a suitable distance apart, extending from the outer circumferential surface of the cushioning portion toward the outer surface and covering the packing, and an extension portion extending from the tip of the light-shielding portion toward the packing along the outer surface, with the packing integrally provided at the tip of the extension portion.

[0016] In this disclosure, the cushioning member integrally comprises a cushioning portion, a light-shielding portion, and an extension portion. The cushioning portion is interposed between the support plate and the flange, with a cylindrical body passing through the inside of the cushioning portion. The light-shielding portion extends from the outer circumference of the cushioning portion toward the outer surface of the case wall, covering the packing and shielding it from light. The inner circumferential surface of the light-shielding portion faces the outer circumferential surface of the flange at an appropriate distance. The extension portion extends from the tip of the light-shielding portion toward the packing, along the outer surface of the wall. The packing is integrally provided at the tip of the extension portion.

[0017] The light-shielding portion is easily exposed to ultraviolet rays and therefore prone to deterioration. However, an extension is interposed between the light-shielding portion and the gasket, and the extension located inside the light-shielding portion is less exposed to ultraviolet rays and therefore less prone to deterioration. Thus, it is possible to prevent damage to the light-shielding portion due to deterioration from spreading to the gasket and causing the gasket to deteriorate as well.

[0018] The airtight structure according to this disclosure is characterized in that a light-shielding piece extends from the periphery of the support plate toward the outer surface, covering at least a portion of the cushioning member, a gap is provided between the outer surface and the tip of the light-shielding piece, and the packing is positioned opposite the gap.

[0019] In this disclosure, a light-shielding piece extends from the periphery of the support plate toward the outer surface of the wall. A gap is provided between the outer surface of the wall and the tip of the light-shielding piece. The packing is arranged at a position facing this gap. However, since the buffer member covers the packing to block light, it is possible to prevent the packing from being exposed to the ultraviolet rays passing through this gap. Further, since at least a part of the buffer member is covered by the light shielding piece and shielded from light, deterioration of the buffer member due to exposure to ultraviolet rays is suppressed.

[0020] This gap is a clearance for absorbing distortion or dimensional error of each member, etc., and it is possible to prevent the inconvenience that the separation distance between the support plate and the outer surface of the wall portion becomes longer than a predetermined value when the light shielding piece contacts the outer surface of the wall portion of the case. As a result, the flange can be appropriately sandwiched between the support plate and the outer surface of the wall portion, and the packing can be appropriately compressed between the flange and the outer surface of the wall portion, so that airtightness can be maintained.

Effect of the Invention

[0021] According to the airtight structure of the present disclosure, airtightness can be maintained over a long period of time.

Brief Description of the Drawings

[0022] [Figure 1] It is a cross-sectional view of the airtight structure according to Embodiment 1. [Figure 2] It is a front view of the airtight structure. [Figure 3] It is a perspective view of the buffer member. [Figure 4] It is a cross-sectional view of the airtight structure according to Embodiment 2. [Figure 5] It is a perspective view of the buffer member. [Figure 6] It is a cross-sectional view of the airtight structure according to Embodiment 3.

Mode for Carrying Out the Invention

[0023] <00001{17}>Hereinafter, embodiments of the present disclosure will be described. In the following description, up and down, front and back, and left and right indicated by arrow signs in the drawings are used.

[0024] Embodiment 1. Figure 1 is a cross-sectional view of the airtight structure according to Embodiment 1. Figure 1 shows the vicinity of the upper part of the flange 22, which will be described later. The airtight structure shown in the figure comprises a case 1, a cylindrical body 2, a packing 3, a support plate 4, and a cushioning member 5.

[0025] Case 1 is, for example, a case that constitutes a switch. Case 1 has a side wall 11. The side wall 11 is a wall portion that extends in the vertical, horizontal, and vertical directions. In Figure 1, the left side (right side) of the side wall 11 is the outside (inside) of Case 1. The front surface of the side wall 11 is part of the outer surface of Case 1. The side wall 11 is provided with through holes 12. Although not shown in the diagram, multiple through holes 12 are arranged side by side.

[0026] Figure 2 is a front view of the airtight structure. The cylindrical body 2 is, for example, an insulating bushing that constitutes a switch. As shown in Figures 1 and 2, the cylindrical body 2 comprises a cylindrical body 21 and a flange 22 integrally with each other. The cylindrical body 21 is cylindrical in shape, and its outer diameter is slightly smaller than the inner diameter of the through-hole 12. The cylindrical body 21 passes through the through-hole 12 coaxially. Inside the cylindrical body 21, for example, a conductor 6 is arranged. The conductor 6 is connected to an electric wire (not shown) on the outside of the case 1 and to a vacuum valve (not shown) on the inside of the case 1.

[0027] The flange 22 is positioned midway through the cylindrical body 21. The outer diameter of the flange 22 is sufficiently larger than the inner diameter of the through hole 12. The flange 22 faces the front surface of the side wall 11.

[0028] The packing 3 shown in Figure 1 is annular in shape. The outer diameter of the packing 3 is larger than the outer diameter of the through hole 12 and less than or equal to the outer diameter of the flange 22. The inner diameter of the packing 3 is larger than the outer diameter of the cylindrical body 21. A fitting groove 31 is provided around the entire circumference of the outer circumference of the packing 3. The packing 3 is attached to the periphery of the through hole 12 by fitting the periphery of the through hole 12 into the fitting groove 31 around its entire circumference.

[0029] After the packing 3 is installed, the cylindrical body 21 of the cylindrical body 2 is inserted through the inside of the packing 3 from the front side of the side wall 11. At this time, the portion of the packing 3 corresponding to the bottom wall of the fitting groove 31 is positioned between the outer surface of the cylindrical body 2 and the inner surface of the through hole 12. In addition, the portion of the packing 3 corresponding to the front side wall of the fitting groove 31 is interposed between the rear surface of the flange 22 and the front surface of the side wall 11.

[0030] The support plate 4 and the cushioning member 5 are located on the outside of the case 1. As shown in Figures 1 and 2, the support plate 4 is rectangular in shape. The shorter side of the support plate 4 is oriented vertically and is longer than the outer diameter of the flange 22. A through hole 41 is provided in the center of the support plate 4 in the direction along the shorter side. Multiple (three in the figures) through holes 41 are arranged along the longer side of the support plate 4 at appropriate intervals from each other, and their number and pitch are equal to the number and pitch of the through holes 12. One side of the support plate 4 faces the front of the side wall 11 and the front of the flange 22, and it is attached to the side wall 11 such that the cylindrical body 21 passes through the through hole 41 coaxially from the rear.

[0031] In this embodiment, a bolt 71, a nut 72, and a washer 73 are used to attach the support plate 4 to the side wall 11. The bolt 71 is a stepped bolt, having a large-diameter disc-shaped head 711, a medium-diameter cylindrical stepped portion 712, and a small-diameter cylindrical shaft portion 713 integrally with each other. The head 711, stepped portion 712, and shaft portion 713 are arranged in this order and provided coaxially with respect to each other. The head 711 is welded to the front surface of the side wall 11 such that the stepped portion 712 and shaft portion 713 face forward and the axial length direction is perpendicular to the front surface of the side wall 11. The shaft portion 713 passes through a through hole (not shown) provided in the peripheral edge of the support plate 4 from the rear. Male threads are provided on the circumferential surface of the shaft portion 713. The head 711 and stepped portion 712 may have the same diameter.

[0032] The support plate 4 is passed through by multiple bolts 71. In this embodiment, as shown in Figure 2, eight bolts 71 are arranged along the periphery of the support plate 4 at appropriate intervals from one another. As shown in Figure 1, the male thread of the shaft portion 713 of the bolt 71 is screwed into the female thread of the nut 72. By placing the support plate 4 between the stepped portion 712 of the bolt 71 and the nut 72 with a washer 73 in between, and tightening the nut 72 firmly, the support plate 4 can be securely attached to the side wall 11. Since the head portion 711 and the stepped portion 712 function as spacers between the side wall 11 and the support plate 4, the distance between the side wall 11 and the support plate 4 can be kept constant even when the nut 72 is tightened firmly.

[0033] By attaching the support plate 4 to the side wall 11, the flange 22 can be sandwiched between the front surface of the side wall 11 and the rear surface of the support plate 4. At this time, the portion of the packing 3 corresponding to the front side wall of the fitting groove 31 is compressed between the front surface of the side wall 11 and the rear surface of the flange 22, and airtight interposition occurs between the front surface of the side wall 11 and the rear surface of the flange 22. With the flange 22 sandwiched between the side wall 11 and the support plate 4, the cylindrical body 2 is supported by the side wall 11 and the support plate 4.

[0034] Light-shielding pieces 42 extend from the edges of the support plate 4 toward the front surface of the side wall 11. In this embodiment, four light-shielding pieces 42 are provided on the four sides of the support plate 4, including the top, bottom, left, and right. Each light-shielding piece 42 is perpendicular to the support plate 4. The two upper and lower light-shielding pieces 42 are parallel to each other, and the two left and right light-shielding pieces 42 are parallel to each other.

[0035] The tip of each light-shielding piece 42 and the front surface of the side wall 11 are spaced apart from each other, and a gap (hereinafter referred to as the non-light-shielding gap) is provided between them. The non-light-shielding gap between the tips of the two upper and lower light-shielding pieces 42 and the front surface of the side wall 11 is opposed vertically to the packing 3 (specifically, the portion of the packing 3 interposed between the flange 22 and the support plate 4). Similarly, the non-light-shielding gap between the tips of the two left and right light-shielding pieces 42 and the front surface of the side wall 11 is opposed horizontally to the packing 3.

[0036] The support plate 4 and each light-shielding piece 42 are integrally provided with each other. For example, the support plate 4 and the light-shielding pieces 42 are formed by the manufacturer raising the four sides of a rectangular metal plate in the same direction. Note that the support plate 4 is not limited to being made by bending a metal plate, but may also be made by molding, for example.

[0037] Figure 3 is a perspective view of the cushioning member 5. The buffer member 5 is a bottomed cylindrical shape with a coaxial through-hole in its bottom wall. More specifically, the buffer member 5 integrally comprises an annular buffer portion 51 and a cylindrical light-shielding portion 52. The buffer portion 51 corresponds to the bottom wall of the bottomed cylinder, which has a coaxial through-hole. The light-shielding portion 52 corresponds to the peripheral wall of the bottomed cylinder. The inner diameter of the light-shielding portion 52 is greater than or equal to the outer diameter of the flange 22.

[0038] As shown in Figure 1, the buffer portion 51 is interposed between the support plate 4 and the flange 22 such that the cylindrical body 21 passes coaxially through the inside of the buffer portion 51 from the rear. The light-shielding portion 52 extends from the outer circumference of the buffer portion 51 toward the front surface of the side wall 11. The tip of the light-shielding portion 52 is in contact with the front surface of the side wall 11 all around. The light-shielding portion 52 covers the packing 3 all around from the outer circumference side of the packing 3. The cushioning member 5 has light-shielding properties and appropriate elasticity. Since the shape of the cushioning member 5 is simple, it can be easily manufactured. For example, the cushioning member 5 is a molded product made of synthetic rubber or synthetic resin.

[0039] With the airtight structure described above, the packing 3 is airtightly interposed between the front surface of the side wall 11 of case 1 and the flange 22 of the cylindrical body 2, thereby preventing gas from entering or leaving case 1 through the gap between case 1 and cylindrical body 2. Since the cushioning portion 51 of the cushioning member 5 is interposed between the support plate 4 and the flange 22, and the packing 3 is interposed between the side wall 11 and the flange 22, deformation or damage to the flange 22 due to external forces from the support plate 4 and the side wall 11 can be prevented.

[0040] The packing 3 is completely covered from both the front and rear by the flange 22 and the side wall 11, and is covered all around from the outer periphery by the light-shielding portion 52 of the cushioning member 5, thereby shielding it from light. Therefore, the packing 3 is prevented from being exposed to ultraviolet rays. Consequently, deterioration of the packing 3 can be prevented over a long period of time, and airtightness can be maintained over a long period of time. Moreover, since there is no need for a separate member to cover and shield the packing 3 from light, the number of parts can be reduced.

[0041] Even without the buffer member 5, the packing 3 is partially covered by the light-shielding pieces 42 on the top, bottom, left, and right, so it is shielded from light to some extent. However, the presence of the buffer member 5 prevents the packing 3 from being exposed to ultraviolet rays that pass through the non-shielding gap. The tip of the buffer portion 51 faces the non-shielding gap, but the portion of the buffer portion 51 excluding the tip is covered and shielded from light by the light-shielding pieces 42, so that the buffer member 5 does not deteriorate due to exposure to ultraviolet rays.

[0042] The non-light-shielding gap is a relief to absorb distortion or dimensional errors in each component, and the contact of the light-shielding piece 42 with the front surface of the side wall 11 prevents the inconvenience of the distance between the support plate 4 and the front surface of the side wall 11 becoming longer than a predetermined value. As a result, the flange 22 is properly sandwiched between the support plate 4 and the front surface of the side wall 11, and the packing 3 can be properly compressed between the flange 22 and the front surface of the side wall 11, thereby maintaining airtightness.

[0043] Furthermore, the case 1 and cylindrical body 2 are not limited to the case and bushing that constitute the switch. The side wall 11 is not limited to wall portions extending vertically, horizontally, or to the left or right. The buffer portion 51 is not limited to an annular shape, but may be a rectangular annular shape, for example, and the light-shielding portion 52 is not limited to a cylindrical shape, but may be a square tube shape, for example. The buffer member 5 is not limited to a configuration in which the buffer portion 51 and the light-shielding portion 52 are integrally formed with each other, but may be interposed between the support plate 4 and the flange 22 and cover the packing 3 to shield from light.

[0044] Next, embodiments 2 and 3 will be described. The configuration of the airtight structure in embodiments 2 and 3 is substantially the same as that of the airtight structure in embodiment 1, and the airtight structure in embodiments 2 and 3 provides substantially the same effects and benefits as the airtight structure in embodiment 1. In the following, the differences from embodiment 1 will be explained, and other components identical to those in embodiment 1 will be denoted by the same reference numerals, and their descriptions will be omitted.

[0045] Embodiment 2. Figure 4 is a cross-sectional view of the airtight structure according to Embodiment 2. As shown in the figure, since the outer diameter of the packing 3 is smaller than the outer diameter of the flange 22, a gap is formed between the front surface of the side wall 11, the rear surface of the flange 22, and the outer circumference of the packing 3. This gap is covered by the light-shielding portion 52 of the buffer member 5, but it is not airtight. Hereafter, this gap will be referred to as an unsealed gap.

[0046] In case 1, the side wall 11 extends vertically, so there is a risk that liquids such as rainwater or dew may enter the unsealed gap by traveling along the front surface of the side wall 11. In particular, if exposed to acidic liquids for a long period of time, the packing 3 may deteriorate. Therefore, the buffer member 5 of this embodiment is provided with a drain port 53 for discharging liquid that has entered the unsealed gap.

[0047] Figure 5 is a perspective view of the cushioning member 5. The drain port 53 is a notch provided at the tip of the light-shielding portion 52, and is, for example, rectangular in shape. Alternatively, the drain port 53 may be a through-hole provided in the light-shielding portion 52.

[0048] As shown in Figure 4, the buffer member 5 is inserted through the cylindrical body 21 of the cylindrical body 2 such that the drain port 53 is located at the bottom of the buffer member 5. At this time, the drain port 53 is located below the portion of the light-shielding part 52 that covers the unsealed gap. In other words, there is a drain port 53 on the lower side of the unsealed gap. Therefore, any liquid that enters the unsealed gap is discharged through the drain port 53. Consequently, it is possible to prevent the packing 3 from being exposed to the liquid that enters the unsealed gap for an extended period of time. The drain port 53 is located at the bottom of the buffer member 5 and is partially covered from below by the light-shielding piece 42. Therefore, ultraviolet rays rarely directly reach the packing 3 through the drain port 53.

[0049] Embodiment 3. Figure 6 is a cross-sectional view of the airtight structure according to Embodiment 3. In the airtight structure of this embodiment, the packing 3 is integrally provided with the cushioning member 5. Therefore, the number of parts can be further reduced. The packing 3 does not need to have a fitting groove 31.

[0050] In Embodiment 1, the inner diameter of the light-shielding portion 52 may be equal to the outer diameter of the flange 22. In this case, the inner circumferential surface of the light-shielding portion 52 may be in contact with the outer circumferential surface of the flange 22 over its entire circumference. On the other hand, in this embodiment, the inner diameter of the light-shielding portion 52 is larger than the outer diameter of the flange 22. The inner circumferential surface of the light-shielding portion 52 is spaced appropriately away from the outer circumferential surface of the flange 22 over its entire circumference and faces the outer circumferential surface of the flange 22.

[0051] The cushioning member 5 further comprises an extension 54. The extension 54 is annular in shape. The outer circumference of the extension 54 is integrally provided with the inner circumference of the tip of the light-shielding portion 52. The outer circumference of the packing 3 is integrally provided with the inner circumference of the extension 54. The axial length of the extension 54 is shorter than the axial length of the packing 3 (i.e., the extension 54 is thinner in the front-rear direction than the packing 3). The packing 3 and the extension 54 are each coaxially opposed to the cushioning portion 51.

[0052] Similar to the first embodiment, the portion of the cylindrical body 21 in front of the flange 22 passes through the inside of the buffer portion 51. The portion of the cylindrical body 21 behind the flange 22 passes through the inside of the packing 3. The packing 3 is compressed between the front surface of the side wall 11 and the rear surface of the flange 22, and is airtightly interposed between them. The light-shielding portion 52 covers the packing 3 from the outer circumference around its entire circumference. In this embodiment, the extension portion 54 extends from the tip of the light-shielding portion 52 toward the packing 3 along the front surface of the side wall 11. The packing 3 is located at the tip of the extension portion 54.

[0053] The light-shielding portion 52 is susceptible to deterioration due to ultraviolet rays passing through the non-light-shielding gap. However, an extension portion 54 is interposed between the light-shielding portion 52 and the packing 3, and the extension portion 54, located inside the light-shielding portion 52, is less exposed to ultraviolet rays and therefore less prone to deterioration. Thus, it is possible to prevent damage to the light-shielding portion 52 due to deterioration from spreading to the packing 3 and causing deterioration of the packing 3. Furthermore, the extension portion 54 is not limited to an annular shape.

[0054] The embodiments disclosed herein should be considered in all respects to be illustrative and not restrictive. The scope of the present invention is intended to include, but not in the sense described above, the equivalents of the claims and all modifications within the claims. The constituent elements (technical features) disclosed in each embodiment are combinable with each other, and new technical features can be formed by these combinations. Furthermore, the independent and dependent claims described in the claims can be combined with each other in any combination, regardless of the form of reference. Moreover, while the claims use a multi-claim format in which claims refer to two or more other claims (multi-claim format), the claims are not limited to this. A multi-claim format in which at least one multi-claim is referenced (multi-multi-claim format) may also be used. [Explanation of symbols]

[0055] 1 case; 11 side wall (wall section); 12 through hole; 2 cylindrical body; 22 flange; 3 packing; 4 support plate; 42 light-shielding piece; 5 buffer member; 51 buffer section; 52 light-shielding section; 53 drain port; 54 extension section

Claims

1. Cases in which through holes are provided in the wall, A cylindrical body having a flange, the flange passing through the through hole so as to face the outer surface of the wall portion, A packing is airtightly interposed between the outer surface and the flange. In an airtight structure equipped with, A support plate through which the cylindrical body is penetrated, and which supports the cylindrical body by sandwiching the flange between itself and the outer surface, A buffer member interposed between the support plate and the flange, and covering the packing to block light, Equipped with, The aforementioned wall portion extends vertically, A gap is formed between the outer surface, the flange, and the packing. The buffer member covers the gap, An airtight structure characterized in that a drain port for discharging liquid that has entered the gap is provided at the lower part of the portion of the buffer member that covers the gap.

2. A case in which a through hole is provided in the wall, A cylindrical body having a flange, the flange passing through the through hole so as to face the outer surface of the wall portion, A packing is airtightly interposed between the outer surface and the flange. In an airtight structure equipped with, A support plate through which the cylindrical body is penetrated, and which supports the cylindrical body by sandwiching the flange between itself and the outer surface, A buffer member interposed between the support plate and the flange, and covering the packing to block light, Equipped with, The cushioning member is Interposed between the support plate and the flange, the cushioning portion through which the cylindrical body passes, The inner circumferential surface faces the outer circumferential surface of the flange at an appropriate distance, and the light-shielding portion extends from the outer circumferential surface of the buffer portion toward the outer surface and covers the packing, An extension extending from the tip of the light-shielding portion toward the packing along the outer surface and They possess each other as one, The airtight structure is characterized in that the packing is integrally provided at the tip of the extension.

3. A case in which a through hole is provided in the wall, A cylindrical body having a flange, the flange passing through the through hole so as to face the outer surface of the wall portion, A packing is airtightly interposed between the outer surface and the flange. In an airtight structure equipped with, A support plate through which the cylindrical body is penetrated, and which supports the cylindrical body by sandwiching the flange between itself and the outer surface, A buffer member interposed between the support plate and the flange, and covering the packing to block light, Equipped with, A light-shielding piece extends from the periphery of the support plate toward the outer surface, covering at least a portion of the buffer member. A gap is provided between the outer surface and the tip of the light-shielding piece. The airtight structure is characterized in that the packing is positioned opposite the gap.

4. A case having through holes in the wall, A cylindrical body having a flange, the flange passing through the through hole so as to face the outer surface of the wall portion, A packing is airtightly interposed between the outer surface and the flange. In an airtight structure equipped with, A support plate through which the cylindrical body is penetrated, and which supports the cylindrical body by sandwiching the flange between itself and the outer surface, A buffer member interposed between the support plate and the flange, and covering the packing to block light, Equipped with, The cushioning member is separate from the packing, The cushioning member is Interposed between the support plate and the flange, the cushioning portion through which the cylindrical body passes, A light-shielding portion extends from the outer circumference of the buffer portion so as to contact the outer surface and covers the packing. An airtight structure characterized by having these elements integrally with one another.

5. The cushioning member is Interposed between the support plate and the flange, the cushioning portion through which the cylindrical body passes, A light-shielding portion extending from the outer circumference of the buffer portion toward the outer surface and covering the packing, The airtight structure according to claim 1 or 3, characterized in that it integrally comprises the elements.

6. The aforementioned wall portion extends vertically, A gap is formed between the outer surface, the flange, and the packing. The buffer member covers the gap, The airtight structure according to any one of claims 2 to 4, characterized in that a drain port for discharging liquid that has entered the gap is provided at the lower part of the portion of the buffer member that covers the gap.

7. The airtight structure according to claim 1 or 3, characterized in that the packing and the cushioning member are provided integrally with each other.

8. The cushioning member is Interposed between the support plate and the flange, the cushioning portion through which the cylindrical body passes, The inner circumferential surface faces the outer circumferential surface of the flange at an appropriate distance, and the light-shielding portion extends from the outer circumferential surface of the buffer portion toward the outer surface and covers the packing, An extension extending from the tip of the light-shielding portion toward the packing along the outer surface and They possess each other as one, The airtight structure according to claim 7, characterized in that the packing is integrally provided at the tip of the extension portion.

9. A light-shielding piece extends from the periphery of the support plate toward the outer surface, covering at least a portion of the buffer member. A gap is provided between the outer surface and the tip of the light-shielding piece. The airtight structure according to claim 1, 2, or 4, characterized in that the packing is positioned opposite the gap.

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