JP2004150576A - Sealing structure - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a sealing structure of members to display sealing performance by making them face against each other by interposing a hardenable liquid sealant, excellent in an initial pressure proofing property and without causing leakage even when oscillation and impact is added to it. <P>SOLUTION: Projected parts along an overall circumference of flanges are provided at a center in the cross direction and on both ends in the cross direction of a mounting surface of the first flange in the sealing structure to seal the flanges by connecting them to each other by interposing the hardenable liquid sealant on a connecting surface of the flanges, the central projected part is projected higher than the projected parts on the both ends in the cross direction, only the central projected part makes contact with the second flange part and the liquid sealant is injected into the central part and a stepped part formed between the projected parts on the both ends when the first flange and the second flange are connected to each other. <P>COPYRIGHT: (C)2004,JPO

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a seal structure for members that face each other and exhibit sealing properties, and more particularly to a seal structure that seals between the seal surfaces by interposing a curable liquid sealant on a flange surface. More specifically, the present invention relates to a seal structure in which a sealant is filled between flanges by providing a unique protrusion structure on the flange surface.
[0002]
[Prior art]
In some cases, it is necessary to seal the inside and outside of automobile parts and electric parts in order to prevent internal liquids and gases from leaking to the outside, and conversely, to prevent external liquids, gases and dirt from entering the inside. Normally, a seal, ie, a seal, can be obtained by bringing the members into close contact with each other. However, even if hard members are brought into close contact with each other, an effective sealing effect cannot be obtained. In such a case, a relatively soft sheet such as a packing or a gasket is sandwiched between the sheets to make contact. At this time, the contact portion is usually called a flange.
[0003]
If the conditions for sealing are moderate, the above structure may be used.However, it is difficult to seal high-pressure components such as automobile engines and those with severe conditions such as violent vibrations with the above-mentioned structure. In-situ molded gaskets are used in which a curable liquid sealing agent such as a liquid gasket is applied between the flanges, the flanges are fastened, and the sealing agent is cured.
[0004]
The in-situ molded gasket is a very effective sealing method because it fills the shape between the flanges and the fine irregularities on the flange surface and cures.However, since it exists as a thin film in the slight gap between the flange contact surfaces, the sealing member When is used in applications with severe vibration, the cured sealant may peel off. In addition, when the flanges are made of different materials such as metal and plastic, a deviation occurs between the flanges due to a difference in the coefficient of thermal expansion, and the liquid sealing agent cured film of the thin film causes interfacial peeling, cohesive failure, and leakage occurs therefrom. There was a problem.
[0005]
For this reason, a method has been devised in which a groove is formed in the flange, a liquid sealant is filled in this portion, and a liquid gasket is applied to the joint of the flange and bonded. The principle is that the liquid sealant filled in the groove portion follows the vibration and the displacement between the flanges to prevent peeling by utilizing the rubber elasticity. However, even if grooves are actually formed, most of the portions between the flanges are thin films, and the grooves are peeled off along the thin film portions, which may cause leakage.
[0006]
Furthermore, the flange is provided with a projection instead of a groove, and the projection is brought into contact with the other flange, and the clearance is formed between both sides of the projection and the other flange, and the sealant is filled with the sealant to improve the structure. These are described in Japanese Patent Nos. 3248435 and 2923657.
[0007]
[Problems to be solved by the invention]
However, in recent years, there has been a tendency that the number of bolts for fastening flanges has been reduced for the purpose of lightness and shortness, and the spacing between the bolts has been increased, so that sufficient surface pressure of the flanges has not been obtained. For this reason, it was not possible to cope with the problem simply by providing the protrusions. Moreover, it is difficult to fill the clearance formed around the above-mentioned protrusion with the sealant, and the liquid sealant is applied to the protrusion and the clearance until the flange is assembled and cured. 4 ran down and became as shown in FIG. 4, and it was not possible to obtain a cured product that could follow the vibration and displacement.
[0008]
As described above, it is important to provide a part filled with a liquid sealant in order to improve the ability to follow the vibration and displacement of the flange, but ordinary curable liquid sealants are cured by the moisture in the air. Because the curing is slow, it becomes difficult to completely cure the sealing agent in the filling portion as the sealing agent filling portion is large. In particular, in the case of a seal for an automobile member, since an initial leak test and a firing test are performed immediately after the engine is assembled, there is a disadvantage that leakage occurs when there are many uncured portions. Further, in the case of the flange shape of Japanese Patent No. 3248435, the liquid sealant sometimes drips in the initial leak test when it is not cured, and there is a risk that not only the sealing property but also the contents may be contaminated.
[0009]
In other words, in order to solve the leakage at the time of the initial pressure, a flange structure in which the contact area between the flanges is large and the sealant filling portion is small is effective, and the followability to the movement of the flange such as vibration and displacement during use is effective. In the case of improvement, there is a contradictory aspect that a flange design having a large clearance and a large sealant filling portion is effective, and it has been difficult to satisfy these.
[0010]
[Means for Solving the Problems]
The inventor of the present invention has made intensive efforts to solve the above problems, and as a result, has accomplished the present invention. That is, the present invention relates to a seal structure in which a flange is joined to each other by interposing a curable liquid sealant on a joint surface of the flange to seal the flanges, and the widthwise center and the both ends in the width direction of the mounting surface of the first flange extend over the entire circumference of the flange. Protrusions are provided, and the center protrusion is a protrusion higher than the protrusions at both ends in the width direction, and only the center protrusion contacts the second flange portion, and the first flange and A sealing structure wherein a liquid sealing agent is filled in a step formed between the central projection and the projections at both ends when the second flange is joined. Further, as a further preferred embodiment of the present invention, it is preferable that the protrusion at the center in the width direction has a structure that is equal to or less than half of the entire first flange width.
[0011]
BEST MODE FOR CARRYING OUT THE INVENTION
In the seal structure of the present invention, for example, as shown in FIG. 1A, the first flange 11 has projections 1, 2, 2 'at the center and both ends in the flange width direction. In addition, the central projection 1 protrudes higher than the projections 2 and 2 'at both ends. This can also be described as a kanji “mountain”. Due to such a configuration, when the first flange and the second flange 12 abut against each other, only the central projection 1 comes into contact with the flange surface of the second flange 12 as shown in FIG. The central projection 1 and the projections 2 and 2 'at both ends are preferably formed continuously without being interrupted over the entire circumference of the flange. Here, the height of the protrusion is the distance from the lowest point of the step formed between the two protrusions to the top of the protrusion. For example, a step formed between the central projection 1 and the end projection 2
Therefore, the liquid sealing agent can be filled in the step portions 3 and 3 ′ formed at the central projection 1 and the projections 2 and 2 ′ at the flange ends. The height h2 of the projections 2 and 2 'at both ends may be lower than the height h1 of the center projection 1, but if it is too low, the liquid sealant cannot be sufficiently filled. The preferred height is h2 / h1 = 0.5-0.9. If h2 / h1 is larger than 0.9, the projections 2 and 2 'at both ends come into contact with the flange surface of the second flange 12 when butted against the second flange, and vibration impact or the like is applied between the flanges. When a stress is applied to separate the flanges, the principle of leverage works and the liquid sealant is peeled off and broken. If h2 / h1 is smaller than 0.5, the liquid sealant cannot be filled and held sufficiently, and the liquid sealant is peeled off and destroyed when the above-mentioned stress is applied. Here, the heights h1 and h2 are distances from the lowest part of the space 3 formed between the two protrusions to the highest part of the protrusion. Also, the projections 2 and 2 'at both ends need not be at the same height.
[0013]
Further, it is preferable that the dimension X of the central projection 1 in the flange width direction be equal to or less than half of the entire first flange width Y. However, if it is too small, the strength of the flange itself is reduced and it is not possible to withstand the surface pressure when the flanges are fastened to each other. Therefore, X is a value obtained by multiplying the dimension of Y by 0.5 to 0.2. preferable. If it is larger than 0.5, the width of the liquid sealant-filled portion becomes small, and it becomes impossible to follow the vibration and displacement.
[0014]
However, when the diameter of the bolt fastening hole becomes larger than the dimension of the central projection, the diameter is not limited to this and may be 0.5 or more. In this case, the surface pressure applied to the flange is very high in the vicinity of the bolted portion even if the portion filled with the liquid sealant becomes smaller at 0.5 or more. This is because there is no peeling or destruction.
[0015]
FIG. 2 shows another example of the flange structure according to the present invention. However, it is not limited to this.
[0016]
In addition, the position of the central projection does not need to be located at the center of the flange symmetrical to the left and right, but may be at any position between both ends of the flange.
[0017]
A curable liquid sealant is applied to the flange portion of the first flange 11 as described above, and is brought into contact with the second flange. Thereafter, the flange is fastened by fastening means such as bolts. As shown in FIG. 3, a liquid sealant is filled in the step portion.
[0018]
The liquid sealant interposed between the flanges in the present invention can be used as long as it has rubber elasticity and adhesiveness after curing, such as a moisture-curable silicone resin, but the present invention has a filling portion of the liquid sealant. Since it takes a very long time to cure the inside of the sealant from the surface of the sealant due to the moisture in the air, it is preferable to use a two-part type that cures by mixing. However, the conventional two-component addition-curable silicone composition had poor adhesion. Therefore, a preferred sealant composition of the present invention is a composition comprising the following (A) to (E).
(A) 100 parts by weight of dimethylpolysiloxane having both ends of a molecular chain blocked by a hydroxyl group and having a viscosity at 25 ° C. of 1,000 to 100,000 mPa · s;
(B) General formula CH ₂ ＣＨCH—Si (ON = CR ¹ R ² ) ₃
(Wherein R ¹ and R ² are the same or different and may be a monovalent hydrocarbon group having 1 to 6 carbon atoms) or a partial hydrolyzate thereof 2 to 15 parts by weight;
(C) Ketone compound An amount in which 0.001 to 1.0 mol of a reactive carbonyl group is present based on 100 parts by weight of the component (A);
(D) an amino compound having a primary amino group: an amount in which 0.001 to 1.0 mol of the primary amino group is present based on 100 parts by weight of the component (A);
(E) 5-150 parts by weight of zinc oxide subjected to surface hydrophobization treatment;
[0019]
With the above-mentioned sealant composition, after mixing the two liquids, it can be cured from the inside without contact with the moisture in the air, and since the original composition is a moisture-curable siloxane, it has excellent adhesive strength and rubber elasticity. Demonstrates excellent sealing performance.
[0020]
【The invention's effect】
The seal structure of the present invention can easily fill the liquid sealant between the flanges by providing not only the protrusion at the center of the flange but also the protrusions at both ends of the flange, and the sealant drips during application or curing. Not flowing. If the configuration of the present invention is not adopted, the sealant drips during curing, and the area of the sealant that comes into contact with the second flange is reduced, so that it is impossible to follow the displacement and movement of the flange due to stress. In addition, the sealing agent that has flowed down flows down inside and outside the flange, and contaminates inclusions and the like. By adopting the configuration of the present invention, those disadvantages do not occur. In addition, when a two-part curable silicone composition having a specific composition is used, good initial pressure resistance can be exhibited even when the volume and clearance of the filling portion are large as in the present invention. Therefore, it can be sufficiently used even on a workpiece such as a casting surface where surface pressure cannot be obtained, and the cost can be reduced.
[0021]
Therefore, according to the seal structure of the present invention, it is possible to obtain the pressure resistance when uncured, to obtain good followability to the vibration in the horizontal and vertical directions, and to obtain high seal reliability. it can.
[0022]
[Brief description of the drawings]
1 is a cross-sectional view showing a flange structure of the present invention; FIG. 2 is a cross-sectional view showing an example of the configuration of the present invention; FIG. 3 is a cross-sectional view of a state in which a sealing agent is interposed in the flange structure of the present invention; Sectional view showing a conventional flange structure [Explanation of symbols]
1. Projection 11 at the center of flange 11 First flange 2, 2 'Projection 22 at the end of flange 2nd flange 3, 3' Step

Claims (3)

In a seal structure in which a flange is joined to each other with a curable liquid sealant interposed on the joint surface of the flange to seal the flanges, a projection is provided at the center in the width direction and at both ends in the width direction of the mounting surface of the first flange. And, the central projection is a projection that is higher than the projections at both ends in the width direction, and only the central projection is in contact with the second flange portion, and the first flange and the second flange are formed. A sealing structure in which a liquid sealing agent is filled into a step formed between the central projection and the projections at both ends when the two are joined. 2. The seal structure according to claim 1, wherein the dimension of the central projection in the width direction is equal to or less than half of the overall dimension of the first flange width. 3. The sealing structure according to claim 1, wherein the curable liquid sealing agent contains the following components.
(A) 100 parts by weight of dimethylpolysiloxane having both ends of a molecular chain blocked by a hydroxyl group and having a viscosity at 25 ° C. of 1,000 to 100,000 mPa · s;
(B) General formula CH ₂ ＣＨCH—Si (ON = CR ¹ R ² ) ₃
(Wherein R ¹ and R ² are the same or different and may be a monovalent hydrocarbon group having 1 to 6 carbon atoms) or a partial hydrolyzate thereof 2 to 15 parts by weight;
(C) Ketone compound An amount in which 0.001 to 1.0 mol of a reactive carbonyl group is present based on 100 parts by weight of the component (A);
(D) an amino compound having a primary amino group: an amount in which 0.001 to 1.0 mol of the primary amino group is present based on 100 parts by weight of the component (A);
(E) 5-150 parts by weight of zinc oxide subjected to surface hydrophobization treatment;

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