JP2006038034A - Metallic gasket - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a metallic gasket capable of restricting deterioration of sealability with the lapse of time in comparison with a current one by restricting the generation of deformation (recess or the like) due to local concentration of excessive load to a bonding surface. <P>SOLUTION: A combustion chamber hole 2 is opened on a central side of a board 1, and a thickness increased part 3 is provided to surround the periphery of the combustion chamber hole 2. A plurality of bolt holes 8 are opened on the peripheral side of the board 1, and dummy beads 9 not contributing for seal are provided on the more peripheral side than the bolt holes 8. The dummy bead 9 is structured of a metal bead 10 and a rubber bead. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention has a function of sealing combustion gas, water pressure, oil pressure, and the like by being interposed between a joint surface of a cylinder block constituting an internal combustion engine and a joint surface of a cylinder head and bolted. The present invention relates to a metal gasket useful as a cylinder head gasket.

  Conventionally, as this type of metal gasket, for example, there is a gasket described in Patent Document 1. That is, a hard stopper (thickened portion) is formed on the inner peripheral side by attaching a grommet to the peripheral portion of the combustion chamber hole or turning back the end portion of the combustion chamber hole of the substrate. In addition, the outer peripheral edge of the substrate and a part of the end of the opening end of the bolt hole are folded back to form a stopper on the outer peripheral side that serves as a counter for the thickened portion, and these stoppers are formed along the seal line. The amount of compressive deformation of the bead is regulated. In the above stopper, a leaf spring or the like may be built in the folded portion or the like to give a slight spring, or a film may be formed on the surface. The contact portion is hard.

Here, as a bead arranged along the seal line, in addition to a soft rubber material (elastic seal material) as in Patent Document 1, as described in Patent Document 2, the substrate itself is bent and formed. It is common practice to form a bead.
JP-A-6-101761 Japanese Patent Laid-Open No. 11-247998

As described above, conventionally, the stopper that regulates the deformation amount of the bead is a hard metal one, and at least the stopper arranged on the outer peripheral side is formed by folding or the like, so that the periphery of the bolt hole Otherwise, it is limited to a partial position, and the surface pressure tends to increase.
In recent years, the evolution of the engine has been remarkably advanced, and the distance between the cylinder bores has become extremely narrow due to the progress of miniaturization, weight reduction and high performance, and the metal gasket placed between the cylinder block and the cylinder head is also in strict demand. It is necessary to respond to the conditions. In addition, due to the high compression ratio in the engine with reduced rigidity, rapid change from low cold to high temperature, etc., partly the opening between the seal faces and displacement between the cylinder block and the cylinder head may occur. The surface width also tends to be narrowed.Accordingly, both the inner peripheral side stopper arranged around the combustion chamber hole and the outer peripheral side stopper arranged on the outer peripheral side have a narrower stopper setting place, that is, the joint surface of the stopper. The opposing area of becomes smaller. As a result, the load is concentrated on the hard and small stopper, and there is a possibility that a part of the joint surface of the cylinder block and the cylinder head is depressed. When the joint surface portion that contacts the stopper is depressed, an excessive surface pressure is applied to the bead, leading to excessive deformation of the bead. In particular, when the cylinder block and the cylinder head are made of a soft material such as aluminum, the above problem becomes large. Moreover, the position where the outer peripheral stopper as described above can be formed is also limited.

The stopper serves to prevent over-compression of the bead formed on the metal plate substrate, and the inner peripheral stopper (thickening portion) seals high-temperature and high-pressure gas due to explosion occurring in the combustion chamber. Have a role.
The present invention focuses on the above points, and can prevent deformation (such as dents) caused by excessive surface pressure concentration on the joint surface and suppress deterioration in sealing performance over time. It is an object to provide a simple metal gasket.

In order to solve the above-described problems, the invention described in claim 1 of the present invention surrounds the end portion of the combustion chamber hole with respect to a substrate made of a thin metal plate having at least a combustion chamber hole and a bolt hole. In the metal gasket in which the thickened portion having a thicker plate thickness than the other portions is provided, and the inner peripheral side seal line is set so as to surround at least the outer periphery of the combustion chamber hole and the thickened portion,
For one or more of the bolt holes, a discarded bead that does not contribute to sealing is provided for the substrate portion located between the bolt hole and the outer peripheral edge of the substrate, and the discarded bead From the synthesis of a metal bead that is bent in a concavo-convex shape and a rubber bead made of an elastic sealing material that adheres to the convex side surface of the metal bead and the concave part on the back side of the convex part and elastically deforms in the plate thickness method together with the metal bead It is characterized by being configured.

  Next, the invention described in claim 2 is directed to the configuration described in claim 1, in which a bead formed along the inner peripheral seal line is protruded on the thickening side by the thickening portion. A metal bead that is bent in a shape or an uneven shape, and a rubber bead made of an elastic sealing material that is fixed to the convex portion side surface and the concave portion on the rear side of the convex portion of the metal bead and elastically deformed in the plate thickness method together with the metal bead It consists of composition.

Next, the invention described in claim 3 is the second aspect in which the end of the bolt hole is folded back or the outer peripheral end of the substrate is partially folded over the configuration described in claim 1 or claim 2. A thickened portion is formed, and the second thickened portion and the discarded bead are shared.
Here, the invention of claim 3 will be supplemented.
The second thickened portion formed by folding the end portion of the bolt hole or by folding one portion of the outer peripheral end portion of the substrate is often formed by this folding because a large area cannot be taken because of the structure. If only the stopper with the above-mentioned second thickened portion having a small area is used, the surface pressure on the stopper may increase due to body expansion due to temperature rise when the bolt is tightened and further when the engine is running, and the seal surface of the engine may be depressed. There is. On the other hand, as in claim 3 of the present application, a discarded bead that does not have a sealing function is formed between the outer periphery of the bolt hole and the outer periphery of the substrate, and an elastic sealing material having elasticity is provided on both surfaces of the metal bead. By using the discarded bead together with the stopper by the second thickened portion, the stopper effect can be further ensured.

When the present invention is adopted, a metal gasket capable of increasing the load on the thickened portion provided around the combustion chamber hole while suppressing the depression of the joint surface of the cylinder head or cylinder block to be sealed when tightening the bolt. Can be provided.
Furthermore, the metal gasket of the present invention primarily seals the high-temperature and high-pressure combustion gas by applying a maximum load to the thickened portion around the combustion chamber hole. The other seal lines seal cooling water and lubricating oil, but the seal pressure is 10 kg / cm ² or less, and the seal line is sealed with an elastic elastic sealing material. Therefore, the overall load can be reduced, the axial force of the bolt can be reduced, and the effect can be exerted more and more on an engine whose rigidity is further reduced by reducing the weight and size.

Next, embodiments of the present invention will be described with reference to the drawings.
FIG. 1 is a plan view showing a metal gasket K according to the present embodiment.
First, the configuration will be described.
The substrate 1 is composed of a thin metal plate such as a stainless steel plate or a mild steel plate. When a low-priced product or the like is targeted, the substrate 1 may be composed of a mild steel plate. In this embodiment, since the bead has a bead structure composed of a metal bead and a rubber bead as will be described later, it is possible to set the bead seal pressure low, and as a result, the substrate 1 involved in the spring of the metal bead. It is possible to set the rigidity of the correspondingly low. That is, even if a mild steel sheet having a low hardness is used, it is possible to ensure a sufficient seal surface pressure by the beads. In addition, this is because the seal line is a face seal with a soft seal material, so the gasket coefficient can be kept low, the overall seal face pressure can be reduced, and the tightening axial force is reduced, resulting in a low seal pressure. This makes it possible to perform a desired seal.

As shown in FIG. 1, a combustion chamber hole 2 is opened at a substantially central portion of the substrate 1. A hard thickened portion 3 is formed on the entire circumference of the end edge of the combustion chamber hole 2 by folding the end portion upward or by fixing another metal plate to the upper surface of the substrate 1. The thickened portion 3 shown in FIG. 1 illustrates a case where the end portion is formed by folding back.
The first seal line SL1 (inner peripheral side seal line) is arranged so as to surround the outer periphery of the combustion chamber hole 2 and the thickened portion 3 in an endless annular shape. Further, a liquid hole 11, a chain chamber hole 7, and a bolt hole 8 are opened on the outer peripheral side of the substrate 1 with respect to the first seal line SL <b> 1. A plurality of bolt holes 8 are provided along the outer peripheral edge of the substrate 1.

  Further, the second and third seal lines SL2 and SL3 are set so as to surround the outer periphery of the first seal line SL1 and the liquid hole 11 and the chain chamber hole 7. A part of the second seal line SL2 and the third seal line SL3 (part D in FIG. 1) is shared. In addition, arrangement | positioning of the seal line shown by this embodiment is an example.

  As shown in FIG. 3, the bead formed along the first seal line SL1 is a full bead-shaped metal bead 4 formed by bending the substrate 1 in the plate thickness direction so as to be convex only upward. And a rubber bead made of elastic sealing materials 13a and 13b formed by molding on both upper and lower surfaces of the metal bead 4. The bead height of the metal bead 4 is set slightly higher than the thickened portion 3. The elastic sealing material 13a on the back side of the convex portion is filled in the concave portion on the back side of the convex portion so as to be substantially flush with the lower surface of the substrate 1. The height of the elastic sealing material 13 b formed on the convex surface side of the metal bead 4 is set to be equal to or slightly higher than the height of the metal bead 4. The height of the elastic sealing material 13b on the convex side is preferably in the range of 0.9 to 1.1 times the height of the metal bead 4. However, as long as the maximum compressive deformation amount of the rubber bead regulated by each thickened portion 3 is smaller than an amount causing compression failure (for example, 40% or more) and a desired spring force can be exhibited, the range is not limited to the above range. . The same applies to the rubber beads of beads arranged along other seal lines.

  Also, the bead formed along the second and third seal lines SL2 and SL3 bends the substrate 1 in the plate thickness direction so as to be convex only upward as shown in FIGS. The half-bead-shaped metal beads 5 and 6 are combined with rubber beads made of elastic sealing materials 14a, 14b, 18a, and 18b formed on the upper and lower surfaces of the metal beads 5 and 6 by molding. The elastic seal members 14a and 18a on the back side of the convex part are filled in the concave part on the back side of the convex part so as to be substantially flush with the lower surface of the substrate 1. The height of the elastic sealing materials 14b, 18b formed on the convex surface side of the metal beads 5, 6 is set to be equal to or slightly higher than the height of the metal beads 5, 6.

As for the bead line along the shared part of the second and third seal lines SL2 and SL3 (part D located between the combustion chamber hole 2 and the chain chamber hole 7), as shown in FIG. Similar to the bead of one seal line SL1, the metal bead 6 is composed of a full bead.
In addition, each bolt hole 8 of the present embodiment is arranged at a position where the distance to the outer peripheral end of the substrate 1 is smaller than the distance to the combustion chamber hole 3, and on the outer peripheral side of each bolt hole 8. In each case, a discarded bead 9 that does not contribute to the seal is formed.

  As shown in FIG. 3, the discarded bead 9 of the present embodiment includes a full bead-shaped metal bead 10 formed by bending the substrate 1 in the thickness direction so as to be convex only downward, and the metal bead. 10 is composed of a rubber bead made of elastic sealing materials 16a and 16b formed on both upper and lower surfaces by molding. The elastic sealing material 16a on the rear side (upper surface side) of the convex portion is filled in the concave portion on the rear side of the convex portion so as to be substantially flush with the upper surface of the substrate 1. The height of the elastic sealing material 16b formed on the convex side surface (lower surface side) of the metal bead 10 is set to be equal to or slightly higher than the height of the metal bead 10. In FIG. 1, reference numeral 12 indicates a bead that connects the discarded beads 9.

Next, the operation and effect of the metal gasket having the above configuration will be described.
When the metal gasket K having the above configuration is loaded between the joint surface of the cylinder block constituting the engine and the joint surface of the cylinder head, and tightened with a tightening bolt (not shown) penetrating the bolt hole 8, the rubber beads of each bead Compresses and deforms to generate a predetermined seal pressure along the seal lines SL1, SL2, and SL3 together with the metal beads 4, 5, and 6 to perform sealing.

  Further, by making the thickened portion 3 around the combustion chamber hole 2 a hard stopper and a seal portion having the highest surface pressure, the high pressure of the explosion combustion pressure at the bore is sealed, and the thickened portion 3 An excessive load deformation of the bead forming the first seal line SL1 formed around is prevented. That is, the thickened portion 3 is formed around the end of the combustion chamber hole 2 to generate a high surface pressure, and the high-temperature and high-pressure combustion gas pressure is primarily sealed. Further, the bead along the first seal line performs secondary sealing of the combustion gas from the combustion chamber side and prevents leakage of cooling water from the outside to the combustion chamber side.

  Here, the load distribution at the time of bolt tightening is large in the vicinity of the tightening bolt and small at a position away from the tightening bolt. Since the position of the tightening bolt to which the tightening load is input is at a position away from the combustion chamber hole 2, assuming that the folded portion 18 and the discard bead 9 are not present on the outer peripheral side of the substrate 1, In order to generate the target high pressure, it is necessary to design it to have a large tightening load. Further, as the tightening load is increased, the joint surface is deformed toward the bolt hole 8 side by the plate thickness difference between the thickened portion 3 and the bolt hole 8 with the thickened portion 3 around the combustion chamber hole 2 as a fulcrum. And further deformed outside the bolt hole 8. In addition, as the tightening load of each bolt is increased, uneven distribution of the tightening load applied to the gasket becomes more prominent, and the surface pressure along the circumferential direction of the thickened portion 3 may be difficult to equalize.

On the other hand, when the folded portion 19 and the discarded bead 9 of the present embodiment are provided on the outer peripheral side of the substrate 1, the folded portion 19 and the discarded bead 9 act as a counter on the thickened portion 3, and the above deformation is caused. In addition, the tightening force can be concentrated around the combustion chamber hole 2 from the peripheral edge side of the substrate 1. That is, the surface pressure at the bead along the first seal line SL1 located on the thickened portion 3 or the outer periphery of the thickened portion increases. As a result, the tightening load can be suppressed accordingly.
Here, assuming the case where the counter action is exerted only by the folded portion 19 formed on the outer peripheral portion of the substrate 1, the folded portion 19 cannot take a wide width, so that an area receiving pressure is reduced and an overcompressed state is obtained. In addition, since the folded portion 19 is hard, the joint surface may be recessed.

  On the other hand, if the discarded bead 9 is employed as in the embodiment of the present application, it is possible to reduce the risk of denting the joint surface due to elasticity. In particular, the discarded bead 9 is not only a soft elastic sealing material whose contact with the joint surface is mainly soft, but even if a high load is applied to the metal bead 10, the surface of the elastic sealing material having the same height as the metal bead 10 may be used. Since the load is handled, it is possible to prevent an excessive load from being applied to the metal bead portion 10 and further prevent the joint surface from being recessed. Further, when the discarded bead 9 is employed, it is possible to receive a load in a wider area than the folded portion, and the counter efficiency is improved. This is particularly effective when the engine is made of a material having low rigidity such as aluminum in order to reduce the weight of the engine.

  Further, the surface pressure in the vicinity of the bolt is reduced, and the change in load applied to the elastic seal material of the bead along the seal line is suppressed by the discarded bead 9, so that the flow of the elastic seal material is suppressed and stable for a long time. Can guarantee the seal. Further, the flow of the elastic sealing members 16 a and 16 b of the discarded bead 9 is also suppressed by the metal bead 10.

  Further, since the surface pressure necessary for sealing the gasket is generated by the elasticity of the metal bead and the elastic sealing material, it is not necessary to increase the hardness of the metal constituting the substrate 1. Fatigue failure is not generated at the bending portion R of the portion. That is, since the sealing surface pressure can be secured by the combined repulsive force of the metal bead and the rubber bead, there is no need for a material having high hardness as the metal plate constituting the substrate 1, and conversely, bending at the time of forming the metal bead by reducing the material hardness. The R portion is prevented from causing fatigue failure due to the vibration amplitude of the engine, and since a high hardness is not required, a mild steel product having a low material unit price can be used.

In addition, in the bead for sealing composed of the above-mentioned metal bead and rubber bead, since the contact with the joint surface is a soft elastic sealing material, it is ensured even if there are minute irregularities or wrinkles on the joint surface. It becomes possible to seal. Further, even if there is a cast hole generated during casting, it can be reliably sealed within the surface width of the elastic sealing material.
Here, the metal bead 6 of the bead along the third seal line SL3 on the outer peripheral side does not need to be a full bead, and is a half bead in the present embodiment. Even in this case, by bending the substrate 1 so as to be convex upward, the elastic sealing material is fixed to the convex side and the concave part on the back side of the convex part to form a rubber bead.

6 to 8 show modified examples of the bead and the discard bead 9 formed along the seal line.
The example shown in FIG. 6 is an example in which a bead formed along the second seal line SL2 is composed of a metal bead 5 made of an upward convex full bead and a synthetic bead of rubber beads placed on both sides thereof. In this case, the discarded bead 9 is composed of a metal bead 10 protruding upward and rubber beads provided on the front and back thereof. Although FIG. 6 illustrates an example in which the metal bead 10 is a full bead, a half bead may be used.

The example shown in FIG. 7 is an example when the metal beads 4 and 5 of the beads formed along the first and second seal lines SL1 and SL2 are configured by half beads. FIG. 8 shows an example in which the thickened portion 3 is formed by attaching a thin plate instead of being folded, and the bead forming the seal line is composed of only the metal beads 4 and 5.
Further, as shown in FIGS. 2 and 9, the second thickened portion is formed by forming the folded portion 17 around the bolt hole 8 or by forming the folded portion 19 at one portion of the outer peripheral portion of the substrate. Then, it may be used in combination with the discarded bead 9.

  Here, in the said embodiment, although the metal bead 10 which comprises the discard bead 9 is comprised by cross-section arc-shaped full bead shape or step shape (half bead), the case where predetermined | prescribed compressive deformation is permitted is illustrated, It is not limited to this. In the case where the tightening load can be kept small, for example, as shown in FIG. 10, the left and right rising portions of the metal bead 10 rise in a step shape, and the metal bead 10 hardly deforms in the plate thickness direction. good. In this case, the area facing the joining surface of the metal bead 10 can be gained, and the rubber bead made of the elastic sealing material 16b is arranged on the side thereof, so that the area of the discarded bead 9 as a whole can be earned, and the joining is made accordingly. Surface deformation can be suppressed. In this case, it is preferable to set the height of the elastic sealing material 16 b higher than that of the metal bead 10.

Here, in the above-described embodiment, the metal gasket used for the one-cylinder engine has been described for ease of explanation. However, the same effect can be obtained with a metal gasket used for a multi-cylinder engine or a water-cooled engine. .
Moreover, in the said embodiment, although illustrated in the shape which becomes convex only to the one surface side of a board | substrate as a metal bead, you may shape | mold so that it may become uneven | corrugated toward the front and back both surfaces. However, the bead width is increased.

It is a top view which shows the metal gasket which concerns on embodiment based on this invention. It is a top view which shows the metal gasket which concerns on embodiment based on this invention. It is AA sectional drawing in FIG. It is BB sectional drawing in FIG. It is CC sectional drawing in FIG. It is AA sectional drawing which shows the modification of the bead based on this invention. It is AA sectional drawing which shows the modification of the bead based on this invention. It is AA sectional drawing which shows the modification of the bead based on this invention. It is sectional drawing which shows the modification around the bolt hole based on this invention. It is sectional drawing which shows another example of a discard bead.

Explanation of symbols

K metal gaskets SL1, SL2, SL3 Seal line 1 Substrate 2 Combustion chamber hole 3 Thickened part 7 Chain chamber hole 8 Bolt hole 9 Discarded bead 10 Metal beads 16a, 16b Elastic seal material 17 Bolt hole folded part 19 Outer end folded part

Claims (3)

At least a combustion chamber hole and a board made of a thin metal plate having a bolt hole are provided with a thickened portion surrounding the combustion chamber hole end and thicker than other portions, and at least the combustion chamber hole And in the metal gasket in which the inner peripheral side seal line is set so as to surround the outer periphery of the thickened portion,
For one or more of the bolt holes, a discarded bead that does not contribute to sealing is provided for the substrate portion located between the bolt hole and the outer peripheral edge of the substrate, and the discarded bead From the synthesis of a metal bead that is bent in a concavo-convex shape and a rubber bead made of an elastic sealing material that adheres to the convex side surface of the metal bead and the concave part on the back side of the convex part and elastically deforms in the plate thickness method together with the metal bead A metal gasket characterized by comprising.   A bead formed along the inner peripheral side seal line, a metal bead formed by bending the substrate into a convex shape or a concavo-convex shape on the thickened side by the thickened portion, a convex portion side surface of the metal bead, and 2. The metal gasket according to claim 1, wherein the metal gasket is composed of a rubber bead made of an elastic sealing material which is fixed to a concave portion on the back side of the convex portion and elastically deforms in the plate thickness method together with the metal bead.   The second thickened portion is formed by folding back the end portion of the bolt hole or by partially folding the outer peripheral end portion of the substrate, and the second thickened portion and the discarded bead are shared. The metal gasket according to claim 1 or 2, wherein

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