JP2005076877A - Seal structure - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To make seal faces smooth, thereby obtaining high sealing property and durability. <P>SOLUTION: While seal faces 2a, 3a of a cylinder head 2 and a cylinder block 3 are made flat by machining process, minute recessed parts are formed by this machining process and blow holes. The minute recessed parts are charged with a filler 5 to make the seal faces smoother than the flat faces, and, additionally, the seal faces 2a, 3a are provided, together with the filler, with a metal gasket 4 with a smooth surface therebetween, which allows the materials for the cylinder head 2 and cylinder block 3 to be exposed. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a seal structure, and more particularly to a seal structure that seals between a seal surface of a first member and a seal surface of a second member.

Today, as a seal structure that seals between the seal surface of the first member and the seal surface of the second member, it is known that a high sealing performance can be obtained if these seal surfaces are smoothly finished and adhered to each other. However, it has been difficult in terms of cost to finish these surfaces smoothly by machining.
Therefore, conventionally, in order to seal the sealing surfaces facing each other, it is common to insert a gasket as a sealing member between the sealing surfaces facing each other as shown in Patent Documents 1 and 2 below.
Japanese Utility Model Publication No. 62-177963 Japanese Patent Laid-Open No. 10-61527

However, even if a gasket is inserted between the sealing surfaces as described above, the sealing surfaces are usually formed with minute recesses by machining or casting, and fluids such as gas and oil are in minute amounts. Leaked from between the concave portion and the gasket, it was not possible to obtain a sufficient sealing performance.
On the other hand, in these Patent Documents 1 and 2, a coating layer is formed on a gasket or a cylinder head, so that the coating layer is bitten into the minute recesses and sealing is performed, but pressure is applied only to the coating layer. As a result, various problems have occurred, such as insufficient durability.
Therefore, the present invention provides a seal structure that can achieve high sealing performance and durability.

That is, the seal structure according to claim 1 forms the seal surface of the first member on a flat surface where the material of the first member is exposed, and fills the minute recesses formed on the surface of the flat surface with a filler. Filling and forming the sealing surface on a smooth surface smoother than the flat surface where both the filler and the material of the first member are exposed,
The seal surface of the second member is formed on a flat surface where the material of the second member is exposed, and a filler is filled in a minute recess formed on the surface of the flat surface, and the seal surface is filled with the filler. And a smooth surface that is smoother than the flat surface where the material of the second member is exposed,
Further, the sealing surface of the first member and the sealing surface of the second member are closely adhered to each other to seal both sealing surfaces.

Further, in the sealing structure according to claim 2, the sealing surface of the first member is formed on a flat surface where the material of the first member is exposed, and a filler is filled in a minute recess formed on the surface of the flat surface. Then, the sealing surface is formed on a smooth surface that is smoother than the flat surface where both the filler and the material of the first member are exposed,
The seal surface of the second member is formed on a flat surface where the material of the second member is exposed, and a filler is filled in a minute recess formed on the surface of the flat surface, and the seal is used as a filler. Forming a smooth surface smoother than the flat surface where the material of the second member is exposed together,
A metal gasket having a smooth surface is interposed between both of these seal surfaces, and the seal surface of the first member and the metal gasket are in close contact with each other, and the seal surface of the second member and the smooth surface of the metal gasket The two sealing surfaces are sealed by sticking them together.

According to the first aspect of the present invention, since the sealing surface of each member is formed on a smooth surface where both the filler and the material of each member are exposed, high sealing performance can be obtained by bringing these sealing surfaces into close contact with each other. Can be obtained.
Moreover, since both the filler and the material of each member are exposed on the seal surface, when both the seal surfaces are brought into close contact, the pressure is dispersed between the filler and the material, and the filler is difficult to sag and is high. Durability can be obtained.

According to the invention of claim 2, since the sealing surface of each member is formed on a smooth surface where both the filler and the material of each member are exposed, a metal gasket having a smooth surface is adhered to the sealing surface. Thus, high sealing performance can be obtained.
In addition, since both the filler and the material of both members are exposed on the surface of the seal surface, when the metal gasket is brought into close contact with the seal surface, the pressure is dispersed between the filler and the material, and the filler is reduced. High durability can be obtained.

FIG. 1 shows a cross-sectional view when the sealing structure according to the present invention is applied to an engine 1, and the engine 1 includes a cylinder head 2 as a first member, and a second member. It consists of a cylinder block 3 as a member and a metal gasket 4 sandwiched between them.
In this embodiment, the cylinder head 2 is a cast product made of aluminum, the cylinder block 3 is a cast product made of cast iron, and the sealing surfaces 2a and 3a of the cylinder head 2 and the cylinder block 3 facing each other are respectively milled or the like. Has been cut.
By cutting the sealing surfaces 2a and 3a, the sealing surfaces 2a and 3a are processed into flat surfaces, but actually, a minute recess of about 2 to 9 μm is formed on the surface.
Further, since the cylinder head 2 and the cylinder block 3 are cast, the cast hole may be exposed as a minute recess on the seal surfaces 2a and 3a, and the recess by the cast hole is generally formed by the above cutting process. It is deeper than the recess.

In this embodiment, the minute recesses formed on the seal surfaces 2a and 3a are filled with a filler 5 made of a resin such as rubber.
Specifically, after the sealing surfaces 2a and 3a of the cylinder head 2 and the cylinder block 3 are cut, the liquefied filler 5 is applied to the entire sealing surfaces 2a and 3a by means of a roller or a spray. Fill the recess.
Thereafter, the filler 5 deposited on the seal surfaces 2a and 3a is removed using a spatula or the like, and the remaining filler is dried, so that the seal surfaces 2a and 3a are formed between the filler and the cylinder head 2 or the cylinder block 3. It is formed on a smooth surface that is smoother than the flat surface where the material is exposed together.

Next, FIG. 2 shows a plan view of the metal gasket 4, and FIG. 1 shows a cross section taken along line AA in FIG.
The metal gasket 4 has a plurality of combustion chamber holes 6 drilled in accordance with the cylinder bores 3b of the cylinder block 3, a plurality of bolt holes 7 through which fastening bolts (not shown) are inserted, and an oil hole through which lubricating oil flows. 8 and a water hole 9 for circulating cooling water are formed, and a cross-sectional circle projecting toward the cylinder head 2 as shown in FIG. An arc-shaped full bead 10 is formed.
Further, the metal gasket 4 of the present embodiment is manufactured from a SUS plate, and the surface thereof is a smooth surface that is smooth with respect to the flat surface of the cylinder head 2 or the cylinder block 3 at the time of the cutting process. ing.

The following effects are obtained by the seal structure of the present embodiment having the above-described configuration.
As a first effect, as in the case of forming a coating layer on a metal gasket as in Patent Documents 1 and 2, high sealing performance can be obtained.
That is, by filling the filler 5 into the minute recesses of the seal surfaces 2a and 3a and making the surface smooth, the gap between the seal surfaces 2a and 3a and the metal gasket 4 is blocked by the filler. Become.
Accordingly, the metal gasket 4 can be brought into close contact with the sealing surfaces 2a and 3a, so that gas and oil are prevented from leaking from these, and high sealing performance can be obtained.

As a second effect, by using the seal structure of the present embodiment, it is possible to reduce oil rise and deterioration of piston sliding performance.
That is, since the seal surfaces 2a and 3a and the metal gasket 4 are both smooth surfaces, sufficient sealing performance can be obtained even when the tightening force between the cylinder head 2 and the cylinder block 3 is small when the engine 1 is assembled. Is possible.
Therefore, when the tightening force is reduced, the load concentrated around the bolt hole 7 is relieved and the cylinder bore 3b is not deformed, so that the oil rise and the piston sliding performance are reduced.

On the other hand, in the said patent document 1, since the coating layer was formed only in the metal gasket, in order to obtain favorable sealing performance, big clamping force was required.
That is, even in the above-mentioned Patent Document 1, a minute recess is formed on the seal surface, but in order to eliminate the gap between the seal surface and the metal gasket, the coating layer of the metal gasket must be bitten into the minute recess. For this purpose, a large tightening force was required.

As a third effect, there is an effect that the manufacturing cost can be reduced.
That is, in the case of the present embodiment, even if the minute recess includes a recess due to a cast hole or the processing accuracy is somewhat poor, the filler 5 is filled regardless of the depth of the minute recess. 3a can be a smooth surface, and a good sealing property can always be obtained.
Therefore, it is not necessary to prevent the formation of a cast hole in the cylinder head 2 or the cylinder block 3, and it is not necessary to increase the processing accuracy at the time of cutting. As a result, the cost of manufacturing can be reduced.

On the other hand, in Patent Document 1, the thickness of the coating layer formed on the metal gasket is set assuming the deepest recess among minute recesses formed on the sealing surface by cutting, and the coating layer is It tried to completely bite into the recess.
For this reason, in order to reduce the thickness of the coating layer, it is necessary to increase the processing accuracy to make the minute concave portions shallow, and a manufacturing cost for improving the processing accuracy is required.
In addition, since the concave portion formed by the cast hole formed on the seal surface is deeper than the concave portion formed by cutting, even if the coating layer set to the depth of the concave portion by cutting is bitten, the concave portion can be completely blocked. It was not possible to obtain good sealability.

As a fourth effect, the durability of the seal between the cylinder head 2 and the cylinder block 3 can be improved.
That is, in this embodiment, since the material of the cylinder head 2 or the cylinder block 3 is exposed on the seal surfaces 2a and 3a in addition to the filler 5, the pressure received by the seal surface from the bore bead of the metal gasket on the cylinder block side, for example. Will be dispersed in the material of the filler 5 and the cylinder block 3.
Therefore, since the pressure of the metal gasket 4 is not applied only to the filler 5, the sag of the filler 5 is prevented and high durability can be obtained as a seal structure.

On the other hand, in Patent Document 1, as described above, the thickness of the coating layer is set assuming the deepest position of the concave portion on the seal surface. Therefore, in the other shallow portion of the concave portion, the coating layer is a concave portion. It will not go into completely.
Then, since the pressure from the metal gasket is applied only to the coating layer located between the metal gasket and the minute recesses, the coating layer falls and the durability of the seal is lowered.
In addition, since the surface of the metal gasket is smooth as described above, it is difficult to adhere the coating layer to the metal gasket. If a coating layer that is too thick is used, the coating layer is more than the metal gasket during engine use. The risk of peeling increases.

Further, in Patent Document 2, a coating layer is also provided on the cylinder head side. As is apparent from FIG. 7 of Patent Document 2, the coating layer covers the entire sealing surface, and the material of the cylinder head is Not exposed from the coating layer.
For this reason, the tightening force is applied to both the coating layer of the metal gasket and the coating layer of the sealing surface of the cylinder head, so that the coating layer falls during use of the engine and the durability of the seal is reduced. End up.

Although the coating layer is not formed on the metal gasket 4 in the above embodiment, a thin coating layer of 10 μm or less may be formed on the surface of the metal gasket 4.
In this way, the coating layer compensates for the lack of filler at a position where the sufficient filler 5 is not filled. Therefore, the sealing surface 2a, 3a and the metal gasket 4 are formed by the filler 5 and the coating layer. Sealing can be performed. Further, in the past, a coating layer having a thickness of 20 to 25 μm was formed on the surface of the metal gasket. However, in this case, the thickness was set to 10 μm or less, so that it is possible to prevent deterioration of the sealing performance due to the sag of the coating layer.
Further, the metal gasket 4 can be omitted unless the sealing structure is such that a high pressure is applied to the sealing portion such as an engine.
In this case, since the surfaces of the seal surfaces 2a and 3a facing each other are made smooth by the filler 5, it is possible to obtain a high sealing performance by simply bringing both the seal surfaces 2a and 3a into close contact with each other. Since the filler 5 and the top of the minute recess are exposed in 2a and 3a, only the filler 5 is not subjected to pressure and high durability can be obtained.

Sectional drawing which shows the seal structure concerning a present Example. The top view which shows the metal gasket of a present Example.

Explanation of symbols

2 Cylinder head 3 Cylinder block 2a, 3a Seal surface 4 Metal gasket 5 Filler

Claims (4)

A seal structure for sealing between a seal surface of a first member and a seal surface of a second member,
The sealing surface of the first member is formed on a flat surface from which the material of the first member is exposed, and a filler is filled in a minute recess formed on the surface of the flat surface, and the sealing surface is filled with the filling material. And a smooth surface which is smoother than the flat surface where the material of the first member is exposed,
The seal surface of the second member is formed on a flat surface where the material of the second member is exposed, and a filler is filled in a minute recess formed on the surface of the flat surface, and the seal surface is filled with the filler. And a smooth surface that is smoother than the flat surface where the material of the second member is exposed,
Further, the sealing structure is characterized in that both the sealing surfaces are sealed by bringing the sealing surfaces of the first member and the second member into close contact with each other. A seal structure for sealing between a seal surface of a first member and a seal surface of a second member,
The sealing surface of the first member is formed on a flat surface from which the material of the first member is exposed, and a filler is filled in a minute recess formed on the surface of the flat surface, and the sealing surface is filled with the filling material. And a smooth surface which is smoother than the flat surface where the material of the first member is exposed,
The seal surface of the second member is formed on a flat surface where the material of the second member is exposed, and a filler is filled in a minute recess formed on the surface of the flat surface, and the seal is used as a filler. Forming a smooth surface smoother than the flat surface where the material of the second member is exposed together,
A metal gasket having a smooth surface is interposed between both of these seal surfaces, and the seal surface of the first member and the metal gasket are in close contact with each other, and the seal surface of the second member and the smooth surface of the metal gasket A seal structure characterized by sealing both sealing surfaces by bringing them into close contact with each other. The metal gasket has a bead that bulges toward either the first member or the second member. The top of the bead and one of the sealing surfaces are in close contact with each other, and the base of the bead and the other The seal structure according to claim 2, wherein the seal surface is closely attached. Forming a thin film coating layer on the surface of the metal gasket at the portion where the seal surface and the metal gasket are in close contact, and filling the concave portion with the filler and the coating layer to seal the seal surface and the metal gasket. The sealing method according to any one of claims 2 and 3.

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