Seal structure and method for manufacturing the seal structure

Abstract

This invention provides a sealing structure that can improve sealing performance by suppressing variations in the thickness of the liquid gasket after curing. [Solution] A sealing structure is provided in which a hardened liquid gasket (20) formed on a first member (11) is compressed between the first member and a second member (70) to seal the space between the first member and the second member, wherein the first member has a liquid-repellent portion (30) that has been treated to repel liquid and a non-liquid-repellent portion (41a) that has not been treated to repel liquid, and the hardened liquid gasket is in contact with the liquid-repellent portion and the non-liquid-repellent portion.

Description

Technical Field

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[0001] The present invention relates to a sealing structure sealed by a liquid gasket after curing.

Background Art

[0007] According to the above configuration, the cured liquid gasket is formed by applying a liquid curable composition to the first member and then curing it. In the sealing structure, the cured liquid gasket is compressed between the first member and the second member to seal the space between the first member and the second member.

[0008] Here, the first member has a liquid-repellent portion that has been treated to repel liquid. Since the cured liquid gasket is in contact with the liquid-repellent portion, when the liquid curable composition is applied to the first member, the curable composition that comes into contact with the liquid-repellent portion is repelled by the liquid-repellent portion. Therefore, the spreading of the applied liquid curable composition to the surface of the first member before it hardens is suppressed, and variations in the height of the curable composition can be suppressed. Consequently, variations in the thickness of the cured liquid gasket can be suppressed, and the cured liquid gasket can be compressed evenly between the first member and the second member, thereby improving the sealing performance of the seal structure.

[0009] Furthermore, the first member has a non-liquid-repellent portion that has not been treated to repel liquid. The cured liquid gasket is in contact with the non-liquid-repellent portion. Therefore, even if the adhesion between the liquid-repellent portion and the cured liquid gasket decreases in the cured liquid gasket compressed by the first and second members, the adhesion between the non-liquid-repellent portion and the cured liquid gasket can be increased. Consequently, movement of the cured liquid gasket relative to the first member can be suppressed, and the cured liquid gasket can be sufficiently compressed by the first and second members to ensure a seal.

[0010] In the second method, at least a portion of the second member that presses against the cured liquid gasket is not treated with a liquid-repellent coating. With this configuration, the adhesion between at least a portion of the second member that presses against the cured liquid gasket and the cured liquid gasket can be increased, and movement of the cured liquid gasket relative to the second member can be suppressed. Therefore, the cured liquid gasket can be sufficiently compressed between the first member and the second member, and the sealing performance of the seal structure can be ensured.

[0011] In the third method, the first member has groove-shaped recesses, a portion of the cured liquid gasket is placed inside the recesses, the remaining portion is placed outside the recesses, and the non-liquid portion is formed on at least a portion of the concave surface of the recesses.

[0012] According to the above configuration, a portion of the cured liquid gasket is placed in a groove-shaped recess, and the remaining portion is placed outside the recess. Therefore, if the cured liquid gasket attempts to move relative to the first member, the portion of the cured liquid gasket placed in the recess catches on the recess, thereby preventing the cured liquid gasket from moving.

[0013] Furthermore, since the non-liquid-repellent portion is formed on at least a portion of the concave surface of the recess, it is possible to suppress the spreading of the applied liquid curable composition onto the surface of the first member compared to the case where the non-liquid-repellent portion is formed on a flat surface. Therefore, it is possible to further suppress variations in the height of the curable composition and, consequently, variations in the thickness of the liquid gasket after curing.

[0014] Furthermore, since groove-like recesses can be used when determining the position to apply the liquid curable composition, the workability when applying the liquid curable composition can be improved.

[0015] In the fourth means, the liquid-repellent portion is formed on the periphery of the opening of the recess in the first member. With this configuration, when the liquid curable composition is applied to the first member, the portion of the liquid curable composition that is dropped outside the recess is easily repelled by the liquid-repellent portion formed on the periphery of the opening of the recess. This makes it possible to suppress a decrease in the height of the curable composition, and consequently, variations in the height of the curable composition, and further suppress variations in the thickness of the liquid gasket after curing.

[0016] In the fifth method, the cross-sectional shape of the concave surface is V-shaped, and the non-liquid-repellent portion is formed over the entire concave surface. With this configuration, when applying the liquid curable composition, the amount of curable composition that flows into the concave surface is reduced, while ensuring a contact area between the cured liquid gasket and the non-liquid-repellent portion. Therefore, movement of the cured liquid gasket is suppressed, and the decrease in the height of the liquid curable composition, and consequently the variation in the height of the curable composition, can be further suppressed.

[0017] In the sixth means, the concave surface includes a bottom surface and a side surface, the non-liquid-repellent portion is formed on the bottom surface, and the liquid-repellent portion is formed on the side surface.

[0018] According to the above configuration, since the non-liquid-repellent portion is formed on the bottom surface of the concave surface, it is possible to suppress the spreading of the applied liquid curable composition onto the surface of the first member compared to the case where the non-liquid-repellent portion is formed on a flat surface. Furthermore, since the liquid-repellent portion is formed on the side surface of the concave surface, when applying the liquid curable composition to the first member, the liquid curable composition is more easily repelled by the liquid-repellent portion formed on the side surface of the concave surface. Therefore, it is possible to further suppress the reduction in the height of the curable composition, and consequently the variation in the height of the curable composition, and to further suppress variations in the thickness of the liquid gasket after curing.

[0019] In the seventh means, the concave surface includes a bottom surface and a side surface, the liquid-repellent portion is formed on the bottom surface, and the non-liquid-repellent portion is formed on the side surface.

[0020] According to the above configuration, since the liquid-repellent portion is formed on the bottom surface of the concave surface, applying the liquid curable composition to the bottom surface of the concave surface makes it easier for the liquid curable composition to be repelled by the liquid-repellent portion. Therefore, it is possible to suppress a decrease in the height of the curable composition, and consequently, to suppress variations in the height of the curable composition, thereby suppressing variations in the thickness of the liquid gasket after curing. Furthermore, since the non-liquid-repellent portion is formed on the side surface of the concave surface, when the cured liquid gasket attempts to move relative to the first member, a portion of the compressed cured liquid gasket adheres closely to the non-liquid-repellent portion formed on the side surface of the concave surface, thereby suppressing the movement of the cured liquid gasket.

[0021] In the eighth means, the first member has a first portion facing the hardened liquid gasket in a first direction for compressing the hardened liquid gasket, and a second portion extending bent from the first portion and facing the hardened liquid gasket in a second direction perpendicular to the first direction, wherein the liquid-repellent portion is formed on the first portion and the non-liquid-repellent portion is formed on the second portion.

[0022] According to the above configuration, the first member has a second portion that bends and extends from the first portion and faces the cured liquid gasket in a second direction perpendicular to the first direction, and the non-liquid-repellent portion is formed on the second portion. Therefore, even if the adhesion between the liquid-repellent portion formed on the first portion and the cured liquid gasket decreases in the cured liquid gasket compressed by the first and second members, the adhesion between the non-liquid-repellent portion formed on the second portion and the cured liquid gasket can be increased. Consequently, movement of the cured liquid gasket relative to the first member can be suppressed, and the cured liquid gasket can be sufficiently compressed by the first and second members to ensure a seal.

[0023] The ninth means is a method for manufacturing a sealing structure that compresses the cured liquid gasket formed on the first member between the first member and the second member to seal between the first member and the second member, a step of forming a liquid-repellent portion and a non-liquid-repellent portion that is not liquid-repellent processed on the first member, a step of applying a liquid curable composition to a predetermined range including at least a part of the liquid-repellent portion in the first member, a step of curing the applied curable composition to form the cured liquid gasket, a step of compressing the cured liquid gasket between the first member and the second member to bring the cured liquid gasket into close contact with the non-liquid-repellent portion, and is provided with.

[0024] According to the above steps, a liquid curable composition is applied to a predetermined range including at least a part of the liquid-repellent portion in the first member. For this reason, the curable composition in contact with the liquid-repellent portion is repelled by the liquid-repellent portion. Therefore, it is possible to suppress the spread of the applied liquid curable composition on the surface of the first member until it is cured, and it is possible to suppress the variation in the height of the curable composition.

[0025] Thereafter, the applied curable composition is cured to form the cured liquid gasket. Here, since the variation in the height of the curable composition is suppressed, it is possible to suppress the occurrence of variation in the thickness of the cured liquid gasket.

[0026] Subsequently, the cured liquid gasket is compressed between the first and second members to ensure close contact between the cured liquid gasket and the non-liquid-repellent portion. Here, variations in the thickness of the cured liquid gasket are suppressed, allowing the cured liquid gasket to be compressed uniformly between the first and second members, thereby improving the sealing performance of the seal structure. Furthermore, even if the adhesion between the liquid-repellent portion and the cured liquid gasket decreases after compression by the first and second members, the adhesion between the non-liquid-repellent portion and the cured liquid gasket can be increased. Therefore, movement of the cured liquid gasket relative to the first member can be suppressed, and the cured liquid gasket can be sufficiently compressed between the first and second members to ensure a good seal.

[0027] The tenth means comprises the steps of forming a groove-shaped recess in the first member, forming the non-liquid-repellent portion on at least a part of the concave surface of the recess, and applying the liquid curable composition to the predetermined range including the non-liquid-repellent portion.

[0028] According to the above process, the non-liquid-repellent portion is formed on at least a part of the concave surface of the groove-shaped recess, and the liquid curable composition is applied to the predetermined range including the non-liquid-repellent portion. Therefore, the groove-shaped recess can be used when determining the position to apply the liquid curable composition, and the workability when applying the liquid curable composition can be improved. Furthermore, compared to the case where the non-liquid-repellent portion is formed on a flat surface, it is possible to suppress the spreading of the applied liquid curable composition on the surface of the first member. Therefore, it is possible to further suppress variations in the height of the curable composition, and consequently variations in the thickness of the liquid gasket after curing.

[0029] The eleventh means includes the step of forming the liquid-repellent portion on the peripheral edge of the opening of the recess in the first member. With this step, when the liquid curable composition is applied to the first member, the portion of the liquid curable composition that is dropped outside the recess is more easily repelled by the liquid-repellent portion formed on the peripheral edge of the opening of the recess. As a result, it is possible to suppress a decrease in the height of the curable composition, and consequently, variations in the height of the curable composition, and further suppress variations in the thickness of the liquid gasket after curing. [Brief explanation of the drawing]

[0030] [Figure 1] A perspective view showing the main body of the PLC I / O case. [Figure 2] A schematic diagram illustrating a conventional method of applying a liquid curable composition to a molded surface. [Figure 3] A schematic diagram illustrating how a liquid curable composition spreads across a surface formed by a conventional technology. [Figure 4] A schematic diagram illustrating a conventional method of compressing a liquid gasket after curing. [Figure 5] A schematic diagram showing an embodiment in which a liquid curable composition is applied to the liquid-repellent layer of a comparative example. [Figure 6] An enlarged view showing an example of a water-repellent texture. [Figure 7] A schematic diagram showing how to compress the liquid gasket after curing in the comparative example. [Figure 8] A schematic diagram showing how the liquid gasket moves after curing in the comparative example. [Figure 9] A partial cross-sectional view showing the seal structure of the first embodiment. [Figure 10] A flowchart illustrating the manufacturing method of a seal structure. [Figure 11] A partial cross-sectional view showing an example of a modification to the seal structure of the first embodiment. [Figure 12] A partial cross-sectional view showing another modification of the seal structure of the first embodiment. [Figure 13] A partial cross-sectional view showing the seal structure of the second embodiment. [Figure 14]A partial cross-sectional view showing the liquid gasket after curing according to the third embodiment. [Figure 15] A partial cross-sectional view showing the seal structure of the third embodiment. [Figure 16] A partial cross-sectional view showing the liquid gasket after curing according to the fourth embodiment. [Figure 17] A partial cross-sectional view showing the seal structure of the fourth embodiment. [Figure 18] A partial cross-sectional view showing an example of a modified seal structure. [Figure 19] A partial cross-sectional view showing other examples of modifications to the seal structure. [Modes for carrying out the invention]

[0031] (First Embodiment) The following describes the first embodiment, which is embodied in the sealing structure of an I / O case for a PLC (Programmable Logic Controller), with reference to the drawings.

[0032] As shown in Figure 1, the PLC I / O case comprises a case body 11 and a lid (not shown).

[0033] The case body 11 (first member) is formed in the shape of a rectangular parallelepiped with an opening in one direction. Inside the case body 11, there is a space for housing electronic components that constitute the PLC I / O. The case body 11 has a female threaded portion 12 into which a male thread (not shown) is screwed for assembling the lid (second member) to the case body 11. The case body 11 and the lid are made of engineering plastics such as PBT (polybutylene terephthalate), aluminum, and iron, for example.

[0034] A forming surface 15 is provided around the entire circumference of the opening 13 of the case body 11, where the hardened liquid gasket 20 will be formed. The forming surface 15 is formed in an annular shape around the periphery of the opening 13. Side walls 17 are erected around the entire circumference of the outer periphery of the forming surface 15. The side walls 17 are formed in an annular shape around the outer periphery of the forming surface 15.

[0035] On the forming surface 15, a cured liquid gasket 20 is formed on the inside of the side wall portion 17. In this embodiment, the cured liquid gasket 20 is, for example, a silicone gel and is formed from an ultraviolet-curable silicone composition (liquid curable composition). The ultraviolet-curable silicone composition is, for example, a composition containing a polyorganosiloxane having (meth)acrylic groups and a radical-type photoinitiator, or a composition containing a polyorganosiloxane having epoxy groups and a photocationic catalyst, but is not limited to these.

[0036] Then, the opening 13 of the case body 11 is closed with the lid, and the male threads are screwed into each female threaded portion 12. As a result, the hardened liquid gasket 20 is compressed between the case body 11 and the lid, sealing the space between the case body 11 and the lid. The case body 11, the hardened liquid gasket 20, and the lid constitute the sealing structure.

[0037] Figure 2 is a schematic diagram showing a conventional method of applying a liquid curable composition Lg to a molded surface 115 (coated surface). The liquid curable composition Lg is dropped from the coating nozzle Nz of the coating apparatus, and the coating nozzle Nz is moved along the molded surface 115. The molded surface 115 is in its as-molded state and has not undergone any special processing.

[0038] As shown in Figure 3, the liquid curable composition Lg applied to the conventional forming surface 115 spreads across the forming surface 115 according to the wettability of the liquid curable composition Lg to the forming surface 115 before curing. The dashed circle C represents a state in which the liquid curable composition Lg has not spread across the forming surface 115. Here, due to variations in wettability caused by variations in the surface condition of the forming surface 115, variations occur in the range (degree of spreading) of the liquid curable composition Lg spreading across the forming surface 115. As a result, as shown in Figure 4, variations occur in the height of the liquid curable composition Lg (the height differs in each part), and consequently, variations occur in the height of the liquid gasket 20 after curing.

[0039] Figure 4 is a schematic diagram showing how to compress a conventional liquid gasket 20 after curing. Due to variations in the height of the cured liquid gasket 20, a recess 20b is formed, and the height of the recess 20b is lower than the uppermost surface 20t. Therefore, when compressing the cured liquid gasket 20 between the forming surface 115 of the case body 11 and the opposing surface 71 of the lid 70, the recess 20b may not be sufficiently compressed, potentially reducing the sealing performance.

[0040] Therefore, as shown in Figure 5, it is conceivable to form a liquid-repellent layer 30 on the surface of the case body 11 (apply a liquid-repellent treatment) so that the liquid curable composition Lg is repelled by the liquid-repellent layer 30. The liquid-repellent layer 30 is, for example, a layer with a water-repellent (liquid-repellent) texture formed on it (a textured layer), as shown in Figure 6. With this configuration, it is possible to suppress the spreading of the liquid curable composition Lg on the surface 31 of the liquid-repellent layer 30 and to suppress variations in the height of the liquid curable composition Lg. The liquid-repellent layer 30 may be a fluororesin layer formed by a fluororesin coating, etc.

[0041] Figure 7 is a schematic diagram showing the compression of a comparative example liquid gasket 20 after curing, which was formed by applying it to the surface 31 of the liquid-repellent layer 30 in Figure 5. The opposing surface 71 of the lid 70 is in its as-molded state and has not undergone any special processing, and is a non-liquid-repellent area. The cured liquid gasket 20 is highly tacky. Therefore, the contact area between the upper part of the liquid gasket 20 and the opposing surface 71 of the lid 70 is tightly bonded, forming an adhesion area 50. On the other hand, the liquid-repellent layer 30 is low tacky. Therefore, the contact area between the lower part of the liquid gasket 20 and the liquid-repellent layer 30 is not tightly bonded, and does not form an adhesion area.

[0042] Therefore, if the cured liquid gasket 20 repeatedly expands and contracts due to temperature changes, or if vibration or shock is applied to the cured liquid gasket 20, the cured liquid gasket 20 may move as shown in Figure 8. In this case, the cured liquid gasket 20 may not be able to be sufficiently compressed, and the sealing performance between the case body 11 and the lid 70 may decrease.

[0043] Therefore, in this embodiment, as shown in Figure 9, a groove-shaped recess 41 is formed in the case body 11. The recess 41 extends along the annular side wall portion 17 shown in Figure 1, and is formed annularly on the inner circumference side of the side wall portion 17 on the forming surface 15. That is, the recess 41 is formed on the forming surface 15 at the position where the hardened liquid gasket 20 is formed. The cross-sectional shape of the recessed surface 41a of the recess 41 is V-shaped. The entire recessed surface 41a (i.e., at least a part of it) is in its as-molded state, has not undergone liquid-repellent processing (special processing), and is a non-liquid-repellent portion.

[0044] In the case body 11, a liquid-repellent layer 30 (liquid-repellent portion) is formed on the peripheral edge 15a of the opening of the recess 41. The liquid-repellent layer 30 is formed in at least the area where the liquid gasket 20 is formed, excluding the area where the recess 41 is formed on the forming surface 15. In other words, the case body 11 has a liquid-repellent portion, which is the liquid-repellent layer 30, and a recess 41 (non-liquid-repellent portion), which is the portion that is not treated with a liquid-repellent process. Note that the parts of the case body 11 other than the portion where the liquid-repellent layer 30 is provided are in their as-molded state and have not undergone any liquid-repellent treatment (special processing).

[0045] The lower portion 20a of the cured liquid gasket 20 is housed within the recess 41. In other words, the lower portion 20a fills the interior of the recess 41. That is, a portion of the cured liquid gasket 20 is located inside the recess 41, while the remaining portion is located outside the recess 41.

[0046] The opposing surface 71 of the lid 70, which is the surface that compresses the hardened liquid gasket 20, is in its as-molded state and has not undergone any liquid-repellent treatment (special processing). Furthermore, the parts of the lid 70 other than the opposing surface 71 are also in their as-molded state and have not undergone any liquid-repellent treatment (special processing).

[0047] Then, the opening 13 of the case body 11 is closed with the lid 70, and the male threads are screwed into each of the female threaded portions 12. As a result, the hardened liquid gasket 20 is compressed between the case body 11 and the lid 70, sealing the space between the case body 11 and the lid 70 with the liquid gasket 20, thus forming a sealing structure.

[0048] The liquid gasket 20, after curing, is highly adhesive. Therefore, the contact area between the upper part of the liquid gasket 20 and the opposing surface 71 of the lid 70 is a contact area 50 where the upper part of the liquid gasket 20 and the opposing surface 71 of the lid 70 are in close contact. Also, the contact area between the lower part 20a of the liquid gasket 20 and the concave surface 41a of the recess 41 of the case body 11 is a contact area 51 where the lower part 20a of the liquid gasket 20 and the concave surface 41a of the recess 41 are in close contact.

[0049] On the other hand, at the peripheral edge 15a of the opening of the recess 41, the liquid-repellent layer 30 and the hardened liquid gasket 20 are in contact. That is, the hardened liquid gasket 20 is in contact with the liquid-repellent layer 30 (liquid-repellent portion) and the concave surface 41a (non-liquid-repellent portion) of the recess 41. The hardened liquid gasket 20 and the side wall portion 17 may or may not be in contact. The portion where the hardened liquid gasket 20 and the side wall portion 17 are in contact becomes a sealed portion. Also, the hardened liquid gasket 20 and the inner wall portion 73 erected from the lid 70 may or may not be in contact. The portion where the hardened liquid gasket 20 and the inner wall portion 73 are in contact becomes a sealed portion.

[0050] Figure 10 is a flowchart showing a method for manufacturing a seal structure. This series of steps may be performed automatically by production equipment, or manually by an operator controlling the production equipment. Furthermore, this series of steps may include both automatically performed and manually performed steps.

[0051] First, a recess 41 is formed on the forming surface 15 of the case body 11 (S10). The recess 41 (non-liquid-repellent portion) may be integrally molded with the side wall portion 17 etc. during the molding of the case body 11, or it may be formed by cutting or other processes after the molding of the case body 11. Then, the concave surface 41a of the recess 41 is left in the as-molded state and no liquid-repellent treatment (special processing) is performed. In other words, the entire (or at least a part of) concave surface 41a of the recess 41 is made a non-liquid-repellent portion.

[0052] Next, a liquid-repellent layer 30 (liquid-repellent portion) is formed by a textured (liquid-repellent) process (S11). The textured process is performed in the area where the hardened liquid gasket 20 is formed, but not in the recessed portion 41, and includes the peripheral edge 15a of the opening of the recessed portion 41. The liquid-repellent layer 30 (liquid-repellent portion) may be integrally molded with the side wall portion 17 etc. when the case body 11 is molded, or it may be processed after the case body 11 is molded.

[0053] Next, a liquid curable composition Lg is applied to a predetermined area including the groove-shaped recess 41 (S12). Specifically, the liquid curable composition Lg is applied in an annular shape along the annular recess 41. At this time, the groove-shaped recess 41 is used to determine the position where the liquid curable composition Lg is applied. The liquid curable composition Lg that comes into contact with the concave surface 41a of the recess 41 spreads onto the concave surface 41a. On the other hand, the liquid curable composition Lg that comes into contact with the liquid-repellent layer 30 is repelled by the liquid-repellent layer 30. As a result, variations in the height of the liquid curable composition Lg are suppressed.

[0054] Next, the applied liquid curable composition Lg is cured by irradiating it with ultraviolet light (S13). The time from applying the liquid curable composition Lg to curing it by irradiating it with ultraviolet light is, for example, several tens of seconds. This forms the cured liquid gasket 20.

[0055] Next, the lid 70 is assembled to the case body 11 (S14). Specifically, the opening 13 of the case body 11 is closed with the lid 70, and the male threads are screwed into each female thread portion 12. As a result, the hardened liquid gasket 20 is compressed between the case body 11 and the lid 70, and the hardened liquid gasket 20 adheres tightly to the opposing surface 71 of the lid 70 and the concave surface 41a of the case body 11. In this way, the space between the case body 11 and the lid 70 is sealed by the liquid gasket 20, and a sealing structure is manufactured.

[0056] The embodiment described in detail above has the following advantages.

[0057] The case body 11 has a liquid-repellent layer 30 formed by a liquid-repellent treatment. Since the cured liquid gasket 20 is in contact with the liquid-repellent layer 30, when the liquid curable composition Lg is applied to the case body 11, the curable composition Lg that comes into contact with the liquid-repellent layer 30 is repelled by the liquid-repellent layer 30. Therefore, the spreading of the applied liquid curable composition Lg onto the forming surface 15 of the case body 11 before it hardens is suppressed, and variations in the height of the curable composition Lg can be suppressed. Consequently, variations in the thickness of the cured liquid gasket 20 can be suppressed, and the cured liquid gasket 20 can be evenly compressed between the case body 11 and the lid 70, thereby improving the sealing performance of the seal structure.

[0058] The case body 11 has a recess 41 that is not treated with a liquid-repellent coating. The cured liquid gasket 20 is in contact with the concave surface 41a of the recess 41. Therefore, even if the adhesion between the liquid-repellent layer 30 and the cured liquid gasket 20 decreases when the cured liquid gasket 20 is compressed between the case body 11 and the lid 70, the adhesion between the concave surface 41a of the recess 41 and the cured liquid gasket 20 can be increased. Consequently, movement of the cured liquid gasket 20 relative to the case body 11 can be suppressed, and the cured liquid gasket 20 can be sufficiently compressed between the case body 11 and the lid 70 to ensure a good seal.

[0059] The opposing surface 71 on the lid 70 that presses against the hardened liquid gasket 20 is not treated with a liquid-repellent coating. With this configuration, the adhesion between the opposing surface 71 on the lid 70 that presses against the hardened liquid gasket 20 and the hardened liquid gasket 20 can be increased, and movement of the hardened liquid gasket 20 relative to the lid 70 can be suppressed. Therefore, the hardened liquid gasket 20 can be sufficiently compressed between the case body 11 and the lid 70, and the sealing performance of the seal structure can be ensured.

[0060] - A portion of the cured liquid gasket 20 is placed inside the groove-shaped recess 41, while the remaining portion is placed outside the recess 41. Therefore, if the cured liquid gasket 20 attempts to move relative to the case body 11, the lower part 20a of the cured liquid gasket 20 placed inside the recess 41 catches on the recess 41, thereby preventing the cured liquid gasket 20 from moving.

[0061] Since a non-liquid-repellent portion is formed over the entire concave surface 41a of the recess 41, it is possible to suppress the spreading of the applied liquid curable composition Lg onto the forming surface 15 of the case body 11, compared to the case where a non-liquid-repellent portion is formed on a flat surface. Therefore, it is possible to further suppress variations in the height of the curable composition Lg, and consequently, variations in the thickness of the liquid gasket 20 after curing.

[0062] • When determining the position to apply the liquid curable composition Lg, the groove-shaped recesses 41 can be used, thereby improving the workability when applying the liquid curable composition Lg.

[0063] In the case body 11, a liquid-repellent layer 30 is formed on the peripheral edge 15a of the opening of the recess 41. With this configuration, when applying the liquid curable composition Lg to the case body 11, the portion of the liquid curable composition Lg that is dropped outside the recess 41 is easily repelled by the liquid-repellent layer 30 formed on the peripheral edge 15a of the opening of the recess 41. Therefore, it is possible to suppress the decrease in the height of the curable composition Lg, and consequently the variation in the height of the curable composition Lg, and further suppress variations in the thickness of the liquid gasket 20 after curing.

[0064] The cross-sectional shape of the concave surface 41a is V-shaped, and the entire concave surface 41a is a non-liquid-repellent area. With this configuration, when applying the liquid curable composition Lg, the amount of curable composition Lg that flows into the recess 41 can be reduced while ensuring a contact area between the cured liquid gasket 20 and the non-liquid-repellent area. Therefore, movement of the cured liquid gasket 20 can be suppressed, and the decrease in the height of the liquid curable composition Lg, and consequently the variation in the height of the curable composition Lg, can be further suppressed.

[0065] A liquid curable composition Lg is applied to a predetermined area of ​​the case body 11 that includes the liquid-repellent layer 30. As a result, the curable composition Lg that comes into contact with the liquid-repellent layer 30 is repelled by the liquid-repellent layer 30. Therefore, it is possible to suppress the spread of the applied liquid curable composition Lg onto the forming surface 15 of the case body 11 before it hardens, and to suppress variations in the height of the curable composition Lg.

[0066] Subsequently, the applied curable composition Lg is cured to form the cured liquid gasket 20. Here, since variations in the height of the curable composition Lg are suppressed, variations in the thickness of the cured liquid gasket 20 can be suppressed.

[0067] Subsequently, the cured liquid gasket 20 is compressed between the case body 11 and the lid 70 to make it adhere tightly to the concave surface 41a (non-liquid-repellent portion) of the case body 11. Here, variations in the thickness of the cured liquid gasket 20 are suppressed, so the cured liquid gasket 20 can be compressed evenly between the case body 11 and the lid 70, improving the sealing performance of the seal structure. Furthermore, even if the adhesion between the liquid-repellent layer 30 and the cured liquid gasket 20 decreases in the cured liquid gasket 20 compressed between the case body 11 and the lid 70, the adhesion between the concave surface 41a and the cured liquid gasket 20 can be increased. Therefore, movement of the cured liquid gasket 20 relative to the case body 11 can be suppressed, and the cured liquid gasket 20 can be sufficiently compressed between the case body 11 and the lid 70 to ensure sealing performance.

[0068] - A non-liquid-repellent area is formed on the entire concave surface 41a of the groove-shaped recess 41, and the liquid curable composition Lg is applied to a predetermined area including the non-liquid-repellent area. Therefore, the groove-shaped recess 41 can be used when determining the position to apply the liquid curable composition Lg, improving the workability when applying the liquid curable composition Lg. Furthermore, compared to the case where a non-liquid-repellent area is formed on a flat surface, it is possible to suppress the spreading of the applied liquid curable composition Lg onto the forming surface 15 of the case body 11. Thus, it is possible to further suppress variations in the height of the curable composition Lg, and consequently, variations in the thickness of the liquid gasket 20 after curing.

[0069] - In the case body 11, a liquid-repellent layer 30 is formed on the peripheral edge 15a of the opening of the recess 41. With this process, when the liquid curable composition Lg is applied to the case body 11, the portion of the liquid curable composition Lg that is dropped outside the recess 41 is easily repelled by the liquid-repellent layer 30 formed on the peripheral edge 15a of the opening of the recess 41. As a result, it is possible to suppress the decrease in the height of the curable composition Lg, and consequently the variation in the height of the curable composition Lg, and further suppress variations in the thickness of the liquid gasket 20 after curing.

[0070] The first embodiment can also be implemented with the following modifications. Parts identical to those in the first embodiment are denoted by the same reference numerals, and their descriptions are used accordingly.

[0071] As shown in Figure 11, a groove-shaped recess 42 may be formed in the case body 11. The recessed surface of the recess 42 includes a bottom surface 42a and a side surface 42b. The entire bottom surface 42a and side surface 42b (or at least a part of the recessed surface) are in their as-molded state and have not undergone any liquid-repellent treatment (special treatment), and are non-liquid-repellent areas. In this case, when a liquid curable composition Lg is applied along the recess 42, the liquid curable composition Lg that is in contact with the bottom surface 42a and side surface 42b of the recess 42 spreads to the bottom surface 42a and side surface 42b. On the other hand, the liquid curable composition Lg that is in contact with the liquid-repellent layer 30 is repelled by the liquid-repellent layer 30. Therefore, variations in the height of the liquid curable composition Lg are suppressed. Then, when the case body 11 and the lid 70 compress the hardened liquid gasket 20, the contact area between the liquid gasket 20 and the bottom surface 42a and side surface 42b of the recess 42 becomes a contact area 51 where the liquid gasket 20 and the bottom surface 42a and side surface 42b are in close contact. Therefore, this configuration can also produce the same effects as the first embodiment.

[0072] As shown in Figure 12, the entire bottom surface 42a and side surface 42b, and the peripheral edge 15a of the opening of the recess 42, may be left in their as-molded state without liquid-repellent treatment (special processing), and may be left as non-liquid-repellent areas. In this case, when the liquid curable composition Lg is applied along the recess 42, the liquid curable composition Lg in contact with the bottom surface 42a and side surface 42b, and the peripheral edge 15a of the recess 42 will spread to the bottom surface 42a and side surface 42b, and the peripheral edge 15a. On the other hand, the liquid curable composition Lg in contact with the liquid-repellent layer 30 will be repelled by the liquid-repellent layer 30. Therefore, variations in the height of the liquid curable composition Lg are suppressed. When the case body 11 and the lid 70 compress the hardened liquid gasket 20, the contact areas between the liquid gasket 20 and the bottom surface 42a, side surface 42b, and peripheral edge 15a of the recess 42 become tightly adhered to each other, forming a contact area 51. Therefore, this configuration can also produce the same effects as the first embodiment.

[0073] (Second Embodiment) In this embodiment, as shown in Figure 13, a trapezoidal recess 43 is formed in the case body 11, and a liquid-repellent layer 30 is formed up to the side surface 43b of the recess 43. The other configurations are the same as in the first embodiment. Parts identical to those in the first embodiment are denoted by the same reference numerals and their descriptions are used accordingly.

[0074] The concave surface of the recess 43 includes a bottom surface 43a and a side surface 43b. The bottom surface 43a (i.e., at least a portion of the concave surface) is in its as-molded state and has not undergone any liquid-repellent treatment (special treatment), making it a non-liquid-repellent area. The side surface 43b is liquid-repellent, and a liquid-repellent layer 30 is formed thereon. In this case, when the liquid curable composition Lg is applied along the recess 43, the liquid curable composition Lg that comes into contact with the bottom surface 43a of the recess 43 spreads onto the bottom surface 43a. On the other hand, the liquid curable composition Lg that comes into contact with the liquid-repellent layer 30 is repelled by the liquid-repellent layer 30. This suppresses variations in the height of the liquid curable composition Lg. When the cured liquid gasket 20 is compressed between the case body 11 and the lid 70, the contact area between the liquid gasket 20 and the bottom surface 43a of the recess 43 becomes a contact area 51 where the liquid gasket 20 and the bottom surface 43a are in close contact. Therefore, this configuration can also produce the same effects as the first embodiment.

[0075] Furthermore, since a liquid-repellent layer 30 is formed on the concave side surface 43b, when applying the liquid curable composition Lg to the case body 11, the liquid curable composition Lg is more easily repelled by the liquid-repellent layer 30 formed on the concave side surface 43b. This further suppresses a decrease in the height of the curable composition Lg, and consequently, variations in the height of the curable composition Lg, thereby further suppressing variations in the thickness of the cured liquid gasket 20.

[0076] (Third embodiment) In this embodiment, as shown in Figure 14, a groove-shaped recess 42 is formed in the case body 11. The recessed surface of the recess 42 includes a bottom surface 42a and a side surface 42b. The upper part of the side surface 42b (i.e., at least a portion of the recessed surface) is in its as-molded state and has not undergone any liquid-repellent treatment (special processing), making it a non-liquid-repellent portion. A liquid-repellent layer 30 is formed on the bottom surface 42a by liquid-repellent treatment. The width of the bottom surface 42a is such that the liquid gasket 20, after curing before compression, does not come into contact with it. That is, a gap is formed between the periphery of the opening of the recess 42 and the liquid gasket 20, after curing before compression. The formed surface 15 is also in its as-molded state and has not undergone any liquid-repellent treatment (special processing), making it a non-liquid-repellent portion. The other configurations are the same as in the first embodiment. Parts identical to those in the first embodiment are denoted by the same reference numerals, and their descriptions are used accordingly.

[0077] In this case, when the liquid curable composition Lg is dropped along the recess 42, the liquid curable composition Lg is repelled by the liquid-repellent layer 30 and does not come into contact with the side surface 42b of the recess 42 and the forming surface 15. Therefore, variations in the height of the liquid curable composition Lg are suppressed. Then, as shown in Figure 15, when the cured liquid gasket 20 is compressed by the case body 11 and the lid 70, the contact area between the liquid gasket 20 and the periphery of the opening of the recess 43 becomes a tightly adhering contact area 51. Therefore, this configuration can also produce the same effects as the first embodiment.

[0078] Furthermore, since a non-liquid-repellent portion is formed on the concave side surface 42b, when the hardened liquid gasket 20 attempts to move relative to the case body 11, a portion of the compressed hardened liquid gasket 20 adheres closely to the non-liquid-repellent portion formed on the concave side surface 42b, thereby suppressing the movement of the hardened liquid gasket 20.

[0079] (Fourth Embodiment) In this embodiment, as shown in Figure 16, no recess is formed on the forming surface 15. The other configurations are the same as in the third embodiment. Parts identical to those in the third embodiment are denoted by the same reference numerals and their descriptions are used accordingly.

[0080] In this case, when the liquid curable composition Lg is dropped onto the forming surface 15, the liquid curable composition Lg is repelled by the liquid-repellent layer 30. This suppresses variations in the height of the liquid curable composition Lg. The liquid curable composition Lg does not come into contact with the side wall portion 17 of the case body 11.

[0081] Then, as shown in Figure 17, when the case body 11 and the lid 70 compress the hardened liquid gasket 20, the contact area between the liquid gasket 20 and the side wall portion 17 becomes a tightly adhering portion 52. Therefore, this configuration can also produce the same effects as the first embodiment. Note that the hardened liquid gasket 20 and the inner wall portion 73 erected from the lid 70 may or may not be in contact. The portion where the hardened liquid gasket 20 and the inner wall portion 73 are in contact becomes a tightly adhering portion.

[0082] In other words, the case body 11 has a first portion 16 that faces the hardened liquid gasket 20 in a first direction (vertical direction) that compresses the hardened liquid gasket 20, and a side wall portion 17 (second portion) that bends and extends from the first portion 16 and faces the hardened liquid gasket 20 in a second direction (horizontal direction) perpendicular to the first direction. A liquid-repellent layer 30 is formed on the first portion 16, and a non-liquid-repellent portion is formed on the side wall portion 17.

[0083] According to the above configuration, even if the adhesion between the liquid-repellent layer 30 formed on the first portion 16 and the hardened liquid gasket 20 decreases after it has been compressed between the case body 11 and the lid 70, the adhesion between the non-liquid-repellent portion formed on the side wall portion 17 and the hardened liquid gasket 20 can be increased. Therefore, it is possible to suppress the movement of the hardened liquid gasket 20 relative to the case body 11, and to ensure a seal by sufficiently compressing the hardened liquid gasket 20 between the case body 11 and the lid 70.

[0084] Furthermore, the first to fourth embodiments can also be implemented with the following modifications. Parts identical to those in the first to fourth embodiments are denoted by the same reference numerals, and their descriptions are used accordingly.

[0085] As shown in Figure 18, the case body 11 may have a pair of side walls 17. The two side walls 17 face each other. The cured liquid gasket 20 is placed between the two side walls 17. The cured liquid gasket 20 is compressed between the forming surface 15 of the case body 11 and the opposing surface 71 of the lid 70. This configuration can also produce the same effects as the first embodiment. The cured liquid gasket 20 and the side walls 17 may or may not be in contact. The portion where the cured liquid gasket 20 and the side walls 17 are in contact becomes a sealed portion. In addition, Figure 18 shows the case where the case body 11 and lid 70 of Figure 18 are applied to the first embodiment, but the case body 11 and lid 70 of Figure 18 can also be applied to the second to fourth embodiments. In that case as well, the same effects as the second to fourth embodiments can be produced.

[0086] As shown in Figure 19, a hole 75 may be formed in the lid 70, and a protrusion 18 that fits (engages) with the hole 75 may be formed on the case body 11. By fitting the protrusion 18 into the hole 75 (so-called snap-fit), the hardened liquid gasket 20 may be compressed between the formed surface 15 of the case body 11 and the opposing surface 71 of the lid 70. Note that in Figure 19, the indication of liquid-repellent and non-liquid-repellent parts is omitted. The configuration shown in Figure 19 can be applied to the first to fourth embodiments. Furthermore, at least a part of the opposing surface 71 of the lid 70, which is the surface that compresses the hardened liquid gasket 20, may be in its as-molded state and not have been treated with a liquid-repellent coating (special processing). That is, the opposing surface 71 of the lid 70, which is the surface that compresses the hardened liquid gasket 20, may include a portion that has been treated with a water-repellent coating.

[0087] The curable composition Lg that forms the liquid gasket 20 is not limited to an ultraviolet-curable silicone composition, but can also be a photocurable silicone composition other than an ultraviolet-curable type, such as a silicone composition containing a polyorganosiloxane having a vinylsiloxane group, a polythiol compound, and a radical-type photoinitiator.

[0088] The curable composition Lg that forms the liquid gasket 20 is not limited to a photocurable composition; a thermocurable composition or a moisture-curable composition can also be used. Even when each embodiment and its modifications are applied to these curable compositions Lg, it is possible to suppress the spreading of the applied liquid curable composition Lg onto the surface of the first member before it hardens, and to suppress variations in the height of the curable composition Lg. Consequently, it is possible to suppress variations in the thickness of the liquid gasket 20 after hardening.

[0089] Each embodiment and its modifications can be applied not only to PLC I / O cases but also to various waterproof (fluid-proof) cases. For example, the waterproof (fluid-proof) case may house an ECU (Electronic Control Unit), battery pack, camera, distance measuring device, sensor, etc. [Explanation of symbols]

[0090] 11...Case body (first component), 20...Liquid gasket after curing, 30...Liquid-repellent layer (liquid-repellent part), 41a...Concave surface (non-liquid-repellent part), 70...Lid (second component).

Claims

1. A sealing structure in which a hardened liquid gasket formed on the first member is compressed between the first member and the second member to seal the space between the first member and the second member, The first member has a liquid-repellent portion that has been treated to repel liquid and a non-liquid-repellent portion that has not been treated to repel liquid. The cured liquid gasket has a sealing structure in which it is in contact with the liquid-repellent portion and the non-liquid-repellent portion.

2. The sealing structure according to claim 1, wherein at least a portion of the second member that presses against the cured liquid gasket is not treated with a liquid-repellent coating.

3. The first member has a groove-shaped recess formed therein. A portion of the cured liquid gasket is placed inside the recess, and the remaining portion is placed outside the recess. The seal structure according to claim 1 or 2, wherein the non-liquid-repellent portion is formed on at least a part of the concave surface of the recess.

4. The seal structure according to claim 3, wherein the liquid-repellent portion is formed on the peripheral edge of the opening of the recess in the first member.

5. The cross-sectional shape of the concave surface is V-shaped, The seal structure according to claim 4, wherein the non-liquid-repellent portion is formed over the entire surface of the concave surface.

6. The aforementioned concave surface includes a bottom surface and a side surface, The non-liquid-repellent portion is formed on the bottom surface. The seal structure according to claim 4, wherein the liquid-repellent portion is formed on the side surface.

7. The aforementioned concave surface includes a bottom surface and a side surface, The liquid-repellent portion is formed on the bottom surface. The seal structure according to claim 3, wherein the non-liquid-repellent portion is formed on the side surface.

8. The first member has a first portion that faces the hardened liquid gasket in a first direction for compressing the hardened liquid gasket, and a second portion that bends and extends from the first portion and faces the hardened liquid gasket in a second direction perpendicular to the first direction. The liquid-repellent portion is formed on the first portion, The seal structure according to claim 1 or 2, wherein the non-liquid-repellent portion is formed in the second portion.

9. A method for manufacturing a seal structure in which a hardened liquid gasket formed on a first member is compressed between the first member and a second member to seal the space between the first member and the second member, The first member comprises the steps of forming a liquid-repellent portion that has been treated to repel liquid and a non-liquid portion that has not been treated to repel liquid, The first member comprises the step of applying a liquid curable composition to a predetermined area including at least a portion of the liquid-repellent portion, A step of curing the applied curable composition to form the cured liquid gasket, A step of compressing the hardened liquid gasket between the first member and the second member to make the hardened liquid gasket adhere to the non-liquid-repellent portion, A method for manufacturing a seal structure, comprising the features described above.

10. The first member comprises the step of forming a groove-shaped recess, A step of forming the non-liquid portion on at least a part of the concave surface of the recess, A step of applying the liquid curable composition to the predetermined area including the non-liquid-repellent portion, A method for manufacturing a seal structure according to claim 9, comprising:

11. The method for manufacturing a seal structure according to claim 10, comprising the step of forming the liquid-repellent portion on the peripheral edge of the opening of the recess in the first member.

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