JP2930833B2 - Metal gasket - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a metal gasket used for sealing a space between opposed contact surfaces between a cylinder head and a cylinder block of a multi-cylinder engine.

[0002]

2. Description of the Related Art In a multi-cylinder engine, a cylinder head and a cylinder block are connected by bolts. To prevent gas from leaking from a mounting surface between the cylinder head and the cylinder block, a metal gasket is provided between the mounting surfaces. Is interposed. As shown in FIG. 1, a metal gasket in which a plurality of cylinder bore holes 2 are formed in a single elastic metal plate 1 having elasticity and beads 3 are formed around each hole 2 is generally well known. I have. This metal gasket is
Due to the tightening force of the bolt, the bead 3 forms a seal portion on the mounting surface to achieve an effective seal. Recently, a metal gasket has been developed in which, between two adjacent holes 2, respective beads 3 meet with each other at an associated portion 4, and a common bead portion 5 is formed between the holes 2 [for example, JP-A-63-210465 (U.S. Pat.
No. 15750) or Japanese Utility Model Publication No. 1-8678].

[0003] The above-described metal gasket will be outlined with reference to FIGS. 10 and 11. In the following drawings, the same parts of the metal gasket are denoted by the same reference numerals.

FIG. 10 is an enlarged explanatory view showing an example of an associated portion of a conventional metal gasket. In FIG. 10, the metal gasket is formed in an arc shape along the hole 2 in the shared bead portion 5 between the holes 2.
The two-dot chain line indicates the center line 6 of the bead.
The center line 6 of the two beads 3 is in contact with the central part of the common bead part 5 between them. Since the bead 3 has such a shape, the bead widths L ₁ , L ₂ (L ₁ =
L ₂ ) is substantially equal to the bead width L ₃ at the center of the common bead portion 5. In contrast, the meeting section 4 where the beads 3 meet
Bead width L ₄ of has about twice the width of the bead width L ₃ of the central portion of the bead width L _1, L ₂ and common bead 5 of the noncontact portion.

As a result, as can be seen from the value of the bead surface pressure (kgf / mm ² ) shown in the graph of FIG. The surface pressure is greatly reduced in the vicinity of the contact portion, that is, in the vicinity of the meeting position (regions X and Y surrounded by circles). However, the surface pressure is a reaction force generated in a bead formed along the hole of the metal gasket when the metal gasket is mounted in a pressed state between the cylinder head and the cylinder block. In particular, the contact pressure is remarkably reduced at a portion (region X) near the center of the common bead portion 5. It is considered that this decrease in the surface pressure is caused by a small spring constant at the joint 4. In other words, since the ratio of the bead width to the bead width is suddenly larger at the meeting position than at the non-meeting portion, the spring constant at the meeting portion 4 becomes smaller, and therefore the surface pressure decreases near the meeting position. Is thought to occur. As described above, in the metal gasket of FIG. 10, since the contact pressure is significantly reduced at the joint portion 4, sufficient sealing performance cannot be ensured with respect to the sealing performance affected by the contact pressure of the bead.

FIG. 11 is an enlarged explanatory view showing another example of the associated portion of the conventional metal gasket. The metal gasket shown in FIG. 11 is an improvement of the metal gasket shown in FIG. In this metal gasket, a bead 3 is formed in an elastic metal plate 1 to perform sealing. A plurality of holes 2 are provided in the elastic metal plate 1, and a bead 3 surrounding the hole 2 is formed around each hole 2. Each bead 3 meets between adjacent holes 2, and the bead 3 has a straight portion 7 at the center of the common bead portion 5. The metal gasket is moved toward the associated portion 4 so that the bead width of the associated portion 4 of the bead 3 for sealing each sealing portion provided on the elastic metal plate 1 is substantially equal to the bead width of the non-associated portion. The bead width of the non-association part was gradually narrowed. In other words, the bead width of the bead width _{L 4} of the meeting part 4 noncontact portion _{L 1, L} 2 _(L
1 = L ₂ ), and by forming the bead width L ₄ of the associated portion ₄ and the bead widths L ₁ and L _{2 of the} non-associated portion to be the same size, the The purpose is to increase the spring constant, avoid the problem of a decrease in the seal pressure at the meeting portion 4, and prevent the surface pressure from becoming uneven. This metal gasket does not
Has a large spring constant, and the surface pressure does not decrease when only the joint portion 4 is taken.

[0007]

However, according to analytical calculation by the finite element method,
Sealing surface pressure is as shown in FIG. 11, significantly decrease in the surface pressure P _L in the meeting part 4 bounds of noncontact portion, which is about half of the surface pressure P _M of the noncontact portion. Also, since the spring constant of the meeting part 4 is increased, the contact pressure P _MAX
Shows a very high value, which results in uneven surface pressure.

The fact that the metal gasket is brought into the unbalanced surface pressure state as described above does not mean that the sealing performance is high. Rather, if the spring constant and the surface pressure are increased, there is a problem of durability, for example. , Which may cause settling or cracking, which is not preferable.

[0009] Therefore, when we consider the shape of the bead of the metal gasket shown in FIG. 11, the bead width L ₄ of the meeting part 4
Despite having the same size as the bead widths L ₁ and L ₂ of the non-associating portion, the joining portion 4 has two bead center lines 6 as indicated by the two-dot chain line. Of course, since the height of the bead 3 does not change between the associated portion 4 and the non-associated portion, the cross-sectional shape of the bead 3 at the associated portion 4 is such that the bead width of the non-associated portion gradually decreases toward the associated portion 4. It has a shape where two sharp peaks are connected. As described above, since the bead itself is originally very thin and the bead width is narrowed at the meeting portion 4, the cross-sectional shape of the bead 3 changes complicatedly and rapidly at the meeting portion 4, and therefore, the At the portion 4, the contact pressure becomes extremely large, and the reaction causes a phenomenon that the contact pressure sharply decreases on both sides of the joining portion 4, and the working of the joining portion 4 is extremely difficult. In particular, it is extremely difficult to manufacture a die for forming the bead 3 having such a complicatedly changing cross-sectional shape, and the actual processing is costly and impossible.

[0010] It is an object of the present invention to form a bead in a shape that does not narrow the bead width at the meeting portion, to form the change in the cross-sectional shape of the bead as small and smooth as possible, and to share the spring constant of the meeting portion. By configuring the spring constant of the bead portion and the single bead portion so as to approach the spring constant of the non-association portion, the peak value of the surface pressure at the association portion is kept as low as possible, and the surface pressure generated at the boundary between the association portion and the non-association portion is reduced. By minimizing the decrease in the surface pressure, equalization of the surface pressure in the vicinity of the joint is ensured, thereby ensuring durability and preventing the occurrence of settling and cracks, and achieving high reliability.
It is constructed so that it can be manufactured at low cost, and furthermore, it is designed to control the surface pressure generated at the associated bead, and to set the spring constant at the associated bead to an appropriate size.
An object of the present invention is to provide a metal gasket in which the load stress of a bead in an associated bead portion does not become extremely high, and settling and cracks are not generated from the associated bead portion and durability can be improved.

[0011]

Means for Solving the Problems The present invention is configured as follows in order to solve the above-mentioned object. That is, according to the present invention, an annular bead for sealing is formed along one of a plurality of cylinder bores formed in an elastic metal plate, with one surface being convex and the other being concave, and the bead is adjacent to the cylinder bore. Each single bead portion formed in a region other than between the cylinder bore hole, two associated bead portions formed in a region where the single bead portion and the adjacent single bead portion meet together, and the associated bead portion The single bead portion is formed between the cylinder bore holes connected to the bead portion, and the bead width of the single bead is determined by the length between the inner border and the outer border along the cylinder bore hole. A bead width of the common bead portion is determined by a length between each of the inner borders extending adjacent to each of the adjacent cylinder bore holes, The common bead portion is formed in a straight shape with substantially the same bead width, and the single bead portion is formed with substantially the same bead width as the common bead portion and along the cylinder bore hole. To make the spring constant or surface pressure of the portion and the spring constant or surface pressure of the common bead portion and the region of the single bead portion adjacent to the associated bead portion close to the spring constant or surface pressure of the shared bead portion,
The association bead portion is formed of a smooth curve having a curvature smaller than the curvature of the inner border of the single bead portion, and is connected to the inner border of the shared bead portion and the inner border of each of the single bead portions. The bead center line of the single bead portion and the bead center line of the shared bead portion are surrounded by an arc-shaped inner border, and the bead center line of the associated bead portion is a curve that smoothly curves or is bent at least at an angle of a right angle or more. And the bead width of the associated bead portion is determined by the length between the arc-shaped inner borders and gradually increases from the shared bead portion to the single bead portion. The present invention relates to a metal gasket characterized by being made.

In the metal gasket, the bead width of the single bead portion is formed to be substantially the same along the circumference of the cylinder bore hole, and the associated bead portion is formed of the single bead portion. An arc-shaped outer border connected by a smooth curve to the outer border and the outer border of the single bead portion adjacent to the outer border, and the inner border of the single bead portion and the inner border of one of the shared bead portions are connected. One of the arc-shaped inner borders connected with a smooth curve by an arc having a curvature smaller than the curvature of the cylinder bore hole, the inner border of the adjacent single bead part, and the other inner border of the common bead part are formed. A circle surrounded by the other arc-shaped inner border connected by a circular arc having a curvature smaller than the curvature of the cylinder bore to be connected. They are formed in the part.

In this metal gasket, in order to control the surface pressure of the meeting bead portion, the meeting surrounded by the arc-shaped outer border, one of the arc-shaped inner borders, and the other of the arc-shaped inner borders is controlled. A surface pressure adjusting recess is formed at the center of the portion.

Further, in this metal gasket, the surface pressure adjusting recess is formed in a triangular shape.

In this metal gasket, the surface pressure of the associated bead portion can be adjusted by adjusting the size and depth of the surface pressure adjusting recess.

In the metal gasket, the bead center line connected to the bead center line of the single bead and the bead center line of the common bead is one meeting point in the meeting bead portion. And the length of the perpendicular to the bead center line from the bead center line to the inner border and the arc-shaped inner border of the bead and the length of the perpendicular to the outer border are substantially excluding the vicinity of the meeting point. The length of the vertical line is the same, and the length is gradually increased near the meeting point and becomes the maximum length at the meeting point.

[0017] In the metal gasket, the joint bead portion may be connected to the bead center line for connecting the bead center lines of the two single beads to each other and the bead center line of each of the single beads. A triangular flat portion surrounded by the bead center line interconnecting the bead center line of the bead portion and the bead center line is formed, and the triangular flat portion is formed from each bead center line to each of the inner borders and each of the arc-shaped inner borders. The lengths of the perpendiculars are substantially the same.

In this metal gasket, the arc-shaped outer border is formed of an arc having a center outside the outer border and extending along a center line of the common bead portion.

[0019]

The metal gasket according to the present invention is constructed as described above and operates as follows. That is, the metal gasket has an arc-shaped inner border having a smooth curve having a curvature smaller than the curvature of the inner border of the single bead in the area of the associated bead, and the inner border of the common bead and the inner border of the single bead. The portion having a larger bead width can be formed shorter than the conventional metal gasket shown in FIG. 10, and the spring constant at the associated bead becomes larger than that of the metal gasket shown in FIG. However, it is not as large as the metal gasket shown in FIG. In addition, the metal gasket has a smaller spring constant than the metal gasket shown in FIG. 11, so that the peak value of the surface pressure at the associated bead portion can be suppressed to a considerably low value. It is possible to considerably suppress the decrease in the surface pressure generated at the boundary of the common bead portion, and to equalize the surface pressure in the vicinity of the associated bead portion.

Further, the metal gasket has a structure in which the bead center lines connected to the bead center line of both single beads and the bead center line of the common bead meet at one meeting point at the meeting bead portion. Can be. In this case, the length of the perpendicular from the center line of the bead to the bead boundary (the inner and outer borders) is substantially constant except for the vicinity of the meeting point, and the length of the perpendicular increases gradually near the meeting point. As a result, the width of the bead in the associated bead portion is small, and the cross-sectional shape of the bead is not significantly changed. Therefore, this metal gasket has a smaller spring constant and a lower peak value of the surface pressure than the conventional metal gasket of FIG. As described above, the peak value of the surface pressure at the associated bead portion can be suppressed to a considerably low value, and the reduction of the surface pressure generated at the boundary between the associated bead portion, the single bead portion, and the non-associated portion of the shared bead portion can be achieved. Can be considerably suppressed, so that the surface pressure in the vicinity of the associated bead portion can be equalized.

In the metal gasket, a bead center line connecting both bead center lines of both single beads to each other, and a bead center line of each single bead and a bead center line of a common bead portion are formed at the associated bead portion. It can have a structure that forms a triangular flat portion surrounded by a bead center line connected to each other. In this case, the Δ portion surrounded by the center line of the three beads is formed in the area of the associated bead portion, and the perpendiculars from the center line to the inner border of the bead and the arc-shaped inner border are substantially the same. 10, the bead length is shorter at a portion where the ratio of the bead width to the bead height is larger than that of the metal gasket of FIG. 10. Therefore, the spring constant at the associated bead portion is larger than that of the metal gasket of FIG. Therefore, in this metal gasket, the decrease in the surface pressure is not so large as in the metal gasket of FIG.

In this metal gasket, a surface pressure adjusting recess is formed at the center of the associated portion of the associated bead portion to control the surface pressure of the bead.
Therefore, the spring constant in the associated bead portion can be set to an appropriate surface pressure by the size of the surface pressure adjusting concave portion.
The load stress of the bead in the associated bead portion does not become extremely high, and no settling or cracks are generated from the associated bead portion, so that the durability can be improved. In addition, the surface pressure can be easily controlled by simply forming the surface pressure adjusting recess in the associated portion of the associated bead portion with a press or the like.

In the metal gasket, the peak value of the spring constant of the associated bead portion of the bead is reduced to approach the spring constant of the shared bead portion, and the spring constant of the region on both sides of the associated bead portion is reduced. Is reduced to approach the spring constant of the single bead portion and the shared bead portion, so that the surface pressure in the vicinity of the associated bead portion can be equalized and an appropriate surface pressure can be obtained.

Further, in this metal gasket, the peak value of the surface pressure of the associated bead portion of the bead is reduced to approach the surface pressure of the common bead portion, and the surface pressure of the region on both sides of the associated bead portion is reduced. Since the decrease in pressure is suppressed to approach the surface pressure of the single bead portion and the common bead portion, the surface pressure in the vicinity of the associated bead portion can be equalized and appropriately controlled, and the sealing performance can be improved.

Further, since the metal gasket can considerably suppress the decrease in the surface pressure generated at the boundary between the associated bead portion and both sides thereof, the surface pressure on both sides of the associated bead portion can be secured, and Since the surface pressure does not become unnecessarily high in the bead portion, the surface pressure in the vicinity of the associated bead portion is equalized, and stable sealing performance can be secured.

[0026]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of a metal gasket according to the present invention will be described below with reference to the drawings. FIG. 1 is a plan view showing a part of a metal gasket according to the present invention. In this metal gasket, a plurality of holes such as a plurality of cylinder bore holes 2 (hereinafter, referred to as holes 2) and bolt holes are formed in one elastic metal plate 1 having elasticity. A bead 3 is formed around each hole 2. The two-dot chain line indicates the center line 6 of the bead 3. When a metal gasket is interposed between the cylinder head and the cylinder block and tightened with a fastening bolt, the bead 3 elastically deforms to form a seal between the mounting surfaces, thereby preventing leakage of gas or oil.

FIG. 2 is an enlarged explanatory view showing one embodiment of the portion between the holes 2 of the metal gasket according to the present invention.
This metal gasket forms a bead 3 for sealing having a convex surface on one surface and a concave surface on the other surface along a plurality of holes 2 formed in the elastic metal plate 1. Bead 3 is hole 2
Each single bead portion 9 in the region C other than the inter-beads, the associated bead portion 4 in the region J where the single bead portion 9 and the adjacent single bead portion 9 meet, and one shared bead portion 5 in the region S between the holes 2 It is composed of

FIG. 2 shows the shape of the bead 3 at a portion between two adjacent holes 2 in the metal gasket, and the dotted lines extending along the holes 2 indicate the inner border 8 and the outer border 8 indicating the bead width of the bead 3. 11 is shown. The common bead portion 5 is formed straight with substantially the same bead width. The single bead portion 9 has substantially the same bead width as the common bead portion 5 and is formed by an arc along the hole 2. Further, the region J of the associated bead portion 4 connects the common bead portion 5 and the single bead portion 9 with a smooth arc having a curvature smaller than the curvature of the single bead portion 9 and moves from the common bead portion 5 to the single bead portion 9. The bead width is formed in an expanded state in which the bead width gradually increases, and is divided into two single bead portions 9 having the same bead width.

In this metal gasket, the bead width L ₁ of the single bead portion 9, the bead width L _{2 of} the adjacent single bead portion 9, and the bead width L ₃ of the common bead portion 5 are substantially the same (L ₁ ≒). L ₂ ≒ L ₃ ). Bead width L of the association bead part 4 where the single bead part 9 and the common bead part 5 meet.
_{In 4} , the bead width gradually increases from the common bead portion 5 to the single bead portion 9, in other words, gradually decreases from the two single bead portions 9 to one common bead portion 5. .

In this metal gasket, FIG.
The sectional shape of the common bead portion 5 in the A section is as shown in FIG. 3, and the single bead portion 9 also has the same sectional shape.
In FIG. 2, a two-dot chain line is a bead center line 6 of each bead portion 5. The bead center line 6 of the single bead section 9 and the bead center line 6 of the adjacent single bead section 9 correspond to the associated bead section 4.
, Bead center lines 6a, 6a formed in an arc shape, that is, an R shape
And both bead center lines 6a, 6a
0 is connected. In the associated bead portion 4, the bead center line 6b connected to the bead center line 6 of the shared bead portion 5 and located on the extension of the bead center line 6 is associated with the two bead center lines 6a, 6a at the meeting point 10. I have. The meeting point 10 of each bead center line 6a, 6a, 6b is located at the center of the meeting part 4. A perpendicular drawn down from each bead center line 6 of the common bead portion 5 and the individual bead portion 9 and each bead center line 6a, 6a, 6b in the associated bead portion 4 to the inner and outer bead boundaries, that is, the inner border 8 and the outer border 11. Are approximately the same except for the vicinity of the meeting point 10,
, And gradually approaches the meeting point 10 and becomes the maximum length at the meeting point 10.

The meeting bead section 4 is composed of a single bead section 9.
Outer border 15 connected to the outer border 11 of the adjacent bead part 9 and the outer border 11 of the adjacent bead part 9 by a smooth curve (that is, an arc shape, that is, an R shape), the inner border 8 of the single bead part 9 and the common bead. One arc-shaped inner border 16 connected by an arc having a curvature smaller than the curvature of the hole 2 connected to one inner border 8 of the portion 5 and a smooth curve, and the inner border 8 of the adjacent single bead portion 9 and the common bead. The portion 5 is formed by a portion surrounded by the other arc-shaped inner border 16 connected by a smooth curve with an arc having a smaller curvature than the curvature of the hole 2 connected to the other inner border 8 of the portion 5.

Next, the spring constant of the metal gasket according to the present invention shown in FIG. 2 and the conventional metal gasket will be compared. The spring constant shown in FIG. 12 is a result obtained by cutting out the common bead portion 5 from this metal gasket. Here, sample A is the conventional metal gasket of FIG. 11, sample B is the conventional metal gasket of FIG. 10, and sample C is the spring constant with respect to the load of the metal gasket of FIG. As can be seen from FIG. 12, when comparing the measured values of the spring constant in the overall shape, Sample C is located between Sample A and Sample B, but there is no significant difference.

However, the spring constant of the bead 3 in the narrow region J of the associated bead portion 4, that is, the associated bead portion 4
1/4 of the common bead portion 5 (the portion corresponding to the graph in FIG. 2) including the finite element method F within the elastic limit range.
Calculation by EM analysis revealed that there was a difference between the analysis values of the spring constant of each metal gasket. The spring constant of sample A is 3.146 × 10 ³ kgf
/ Mm, the spring constant of sample B is 1.517 × 10 ³ k
gf / mm, the spring constant of sample C is 1.582 × 10
It was ³ kgf / mm. Thus, it can be seen that Sample C has a slightly higher spring constant than Sample B and is much lower than Sample A. Note that the spring constant of the associated bead portion 4 alone is set to a practical range of deflection of 100 to 15.
When actually measured at 0 μm, the spring constant of sample A is high, the spring constant of sample B is small, and sample C is located in the middle. The tendency similar to the value calculated by the analysis by the finite element method FEM is similar. I found it.

FIG. 2 shows the surface pressure of the bead, that is, the reaction force generated when the metal gasket is tightened between the cylinder block and the cylinder head and mounted in a compressed state.
And a conventional metal gasket shown in FIGS. 10 and 11 will be compared. Meeting Bead 4
The peak value of the surface pressure seen in FIG. 11 is considerably smaller than that in FIG. 11 and slightly smaller than that in FIG. Looking at the decrease in surface pressure generated before and after the associated bead portion 4, the metal gasket shown in FIG. 2 shows that the surface pressure of the single bead portion 9 and the adjacent single bead portion 9 are reduced. No degradation occurs. In addition, the decrease in surface pressure on the side of the common bead portion 5 is smaller than that in FIG. That is,
It can be seen that the metal gasket of FIG. 2 has a more even surface pressure than the conventional metal gasket.

FIG. 4 is an enlarged view showing another embodiment between the holes of the metal gasket. FIG. 5 is an enlarged view of a main part of an associated portion of the metal gasket shown in FIG. Bead center lines 6c and 6 of the single bead portion 9 and the common bead portion 5 indicated by a two-dot chain line.
c and 6d meet at the meeting point 10 at an angle of 120 degrees to each other. Thus, the bead center lines 6c, 6c,
The angle at which 6d intersects between two adjacent ones is 120
Due to the degree, the surface pressure can be made more uniform than that of the metal gasket shown in FIG.

FIG. 6 is an enlarged view showing still another embodiment between the holes of the metal gasket, and FIG. 7 is an enlarged sectional view of the associated bead portion along line BB of the metal gasket shown in FIG. The shape of the center line of the bead in the associated bead portion 4 is the same as the center line of the bead in the embodiment enlarged and shown in FIG. Referring also to FIG. 8, the bead center line 6 of the single bead 9 in the association bead 4
Are connected to the bead center line 6 of the adjacent single bead portion 9 by a bead center line 6e describing an arc. In addition, the bead center line 6 of the single bead section 9 and the common bead section 5
The bead center line 6 and the center line 6 of the adjacent single bead portion 9 and the center line 6 of the common bead portion 5 are also connected to each other by arcuate bead center lines 6f, 6f. Therefore, three arc-shaped borders 15, 16 and 16 (specifically, arc-shaped bead center line 6
e, 6f, 6f), a flat surface 14 is formed. The shape of the BB cross section including the flat surface 14 is as shown in FIG. Also, the metal gasket is formed so that the lengths of perpendiculars drawn from the bead center line 6 including the bead center lines 6e, 6f, 6f to the inner border 8 including the arc-shaped inner border 16 of the bead are substantially the same. Is formed. This metal gasket can also suppress the peak value of the surface pressure at the associated bead portion 4 to a considerably low value as well as the above-described respective embodiments, and can significantly suppress the reduction of the surface pressure generated at the boundary on both sides of the associated bead portion 4. Therefore, the surface pressure in the vicinity of the associated bead portion 4 can be equalized.

As shown in FIGS. 8 and 9, the metal gasket of this embodiment has an arcuate outer border 15, one of the arcuate inner borders 16 and the other, for controlling the surface pressure of the associated bead portion 4. The surface pressure adjusting recess 13 can be formed at the center of the meeting portion 17 surrounded by the arc-shaped inner border 16. The surface pressure adjusting recess 13 is formed in a substantially triangular shape, one surface is formed in a concave shape and the other surface is formed in a convex shape, and is formed at a height smaller than the thickness of the bead 3. Surface pressure adjusting recess 1 in the center of flat surface 14
3, the bead of the associated bead portion 4 is formed into a triangular bead composed of three-sided bead portions 18,
The bead width of the triangular bead is smaller than the bead width of the single bead portion 9 and the common bead portion 5. The configuration of the bead center lines 6e and 6f has already been described, and thus will not be described here.

In this metal gasket, when the size of the surface pressure adjusting recess 13 is increased, the bead width of the associated bead portion 4 is further reduced. Further, when the depth of the surface pressure adjusting recess 13 is increased, the three bead portions 18 of the associated bead portion 4 are formed.
Becomes acute and the surface pressure increases. Thereby, the surface pressure of the associated bead portion 4 can be adjusted to an appropriate surface pressure by controlling the size and depth of the surface pressure adjusting recess 13.

Therefore, in the metal gasket shown in FIGS. 8 and 9, by forming the surface pressure adjusting recess 13 in the associated bead portion 4, the peak surface pressure at the associated bead portion 4 can be reduced.
It is possible to reduce the surface pressure at the boundary between the associated bead part 4 and the single bead part 9 and the boundary part between the associated bead part 4 and the common bead part 5 without abruptly lowering the surface pressure. The surface pressure of the single bead portion 9 and the common bead portion 5 can be approximated, the surface pressure can be controlled to be uniform over the entire circumference of the hole 2, and the sealing performance of the metal gasket can be improved.

[0040]

The metal gasket according to these inventions
The configuration described above has the following effects. That is, in the metal gasket according to the present invention, since the spring constant at the associated bead portion can be set to an appropriate value, the load stress of the bead at the associated bead portion does not become extremely high. Therefore, this metal gasket does not cause settling or cracking from the bead, and can improve durability.

In addition, since this metal gasket has a bead shape in which the change in the bead width is small and the cross-sectional shape of the bead does not change so much, the bead is formed at the associated bead portion as in the conventional metal gasket. There is no need to squeeze, making the mold easier to manufacture, easier to manufacture, and lowering manufacturing costs.

Further, in this metal gasket, a decrease in the surface pressure generated at the boundary between the associated bead portion and the non-associated bead portion can be considerably suppressed, so that the surface pressure at the non-associated bead portion can be secured. Since the surface pressure does not increase unnecessarily in the associated bead portion, the surface pressure near the associated bead portion is equalized, and stable sealing performance can be secured.

In this metal gasket, a surface pressure adjusting recess is formed at the center of the associated portion of the associated bead portion to control the surface pressure of the bead.
Therefore, the spring constant in the associated bead portion can be set to an appropriate surface pressure by the size of the surface pressure adjusting concave portion.
The load stress of the bead in the associated bead portion does not become extremely high, and no settling or cracks are generated from the associated bead portion, so that the durability can be improved. In addition, the surface pressure can be easily controlled by simply forming the surface pressure adjusting recess in the associated portion of the associated bead portion with a press or the like.

[Brief description of the drawings]

FIG. 1 is a schematic plan view showing one embodiment of a metal gasket according to the present invention.

FIG. 2 is an enlarged explanatory view showing one embodiment of a bead between holes of the metal gasket.

FIG. 3 is a sectional view taken along line AA in FIG. 2;

FIG. 4 is an enlarged explanatory view showing another embodiment of a bead between holes of the metal gasket.

FIG. 5 is an enlarged explanatory view of an associated bead portion showing a portion denoted by reference numeral D in FIG. 4;

FIG. 6 is an enlarged explanatory view showing another embodiment of a bead between holes of the metal gasket.

FIG. 7 is an enlarged cross-sectional view of the association bead portion along line BB in FIG. 6;

FIG. 8 is an enlarged explanatory view showing another embodiment of the associated bead portion indicated by reference numeral E in FIG.

9 is an enlarged cross-sectional view of the associated bead portion along line CC in FIG. 8;

FIG. 10 is an enlarged explanatory view showing an example of an associated portion of a conventional metal gasket.

FIG. 11 is an enlarged explanatory view showing another example of a joint portion of a conventional metal gasket.

FIG. 12 is a graph comparing the measurement results of the spring constant of each metal gasket shown in FIGS. 2, 10 and 11;

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Elastic metal plate 2 Cylinder bore hole 3 Bead 4 Associative bead part 5 Common bead part 6, 6a-6f Bead center line 8 Bead boundary line (width line) 9 Individual bead part 10 Joint point 13 Surface pressure adjusting concave part 14 Flat part 15 Arc-shaped outer border 16 Arc-shaped inner border 17 Meeting part 18 Bead part

──────────────────────────────────────────────────続 き Continued on front page (58) Field surveyed (Int.Cl. ⁶ , DB name) F16J 15/08 F02F 11/00

Claims (8)

(57) [Claims] 1. A sealing annular bead having a convex surface on one side and a concave surface on the other side is formed around a plurality of cylinder bores formed in an elastic metal plate, wherein the beads are adjacent to the cylinder bores. Each single bead portion formed in a region other than between the cylinder bore hole, two associated bead portions formed in a region where the single bead portion and the adjacent single bead portion meet together, and the associated bead A single bead portion formed between the cylinder bore holes connected to each other, the bead width of the single bead is determined by the length between the inner border and the outer border along the cylinder bore hole, In the metal gasket, a bead width of the common bead portion is determined by a length between the inner borders extending adjacent to the adjacent cylinder bores. Use bead portion is formed in a straight shape in substantially the same bead width, the single bead portion is formed along and the cylinder bore hole in the common bead portion substantially the same bead width, further the association bead portion Spring constant or surface
Pressure and said meeting of said shared bead section and said single bead section
The spring constant or surface pressure of the area near the bead is
To approximate the spring constant or the surface pressure of the use bead portion, the association bead portion of the smooth consists curve and the common bead portion having a curvature <br/> smaller curvature of the inner border of the sole bead portion and the inner border of said each single bead portions
A pair of arcuate inner border to be connected to said inner border
Surrounded by each bead center line of the two independent bead portions.
The bead center line of the common bead section is the
A smoothly curved curve or at least a right angle
The bead center line consisting of the curves that bend at the above angles
Connected to each other and the bead width of the associated bead portion is
A metal gasket, which is defined by a length between the arc-shaped inner borders , and is formed to be gradually larger from the common bead portion to the single bead portion. 2. The bead width of the single bead portion is formed to be substantially the same width around the cylinder bore hole, and the associated bead portion is adjacent to the outer border of the single bead portion. arcuate outer baud da connecting a smooth curve and the outer border of the sole bead portion to
When the single bead portion and the inner border and the common bead portion while the inner border and said cylinder bore hole while the arcuate inner baud da connecting a smooth curve in an arc of curvature less than the curvature of the connection of the When the single bead portion and the other of the arcuate inner inner border and the other of said inner border of said common bead portion connected by a smooth curve in an arc of curvature less than the curvature of the cylinder bore hole for connecting the adjacent metal gasket according to claim 1, characterized in that it is formed at a meeting portion surrounded by the baud da. 3. The center of the meeting portion surrounded by the arc-shaped outer border, one of the arc-shaped inner borders, and the other of the arc-shaped inner borders for controlling a surface pressure of the meeting bead portion. The metal gasket according to claim 2, wherein a pressure adjusting recess is formed. 4. The metal gasket according to claim 3, wherein the surface pressure adjusting recess has a triangular shape. 5. The metal gasket according to claim 3, wherein the surface pressure of the associated bead portion is adjusted by adjusting the size and depth of the surface pressure adjusting recess. 6. Oite the meeting bead portion, said both single
At the bead center line of the German bead and the common bead
In each bead connected to the bead center line respectively
Core wire associated with one meeting point, the bead, the bead
The inner voter and the arc of the bead from the bead center line
It is substantially the same length of the length of the normal to Jo inner border and perpendicular to the outer border and is except for the vicinity of the front Symbol Junction, 且
One metal gasket according to claim 1, the length of the perpendicular line is characterized in that it is formed so as to maximize the length in the meeting point gradually becomes longer near the meeting point. 7. the meeting bead portion, said both alone Bee
In the bead interconnecting the bead centerlines of the bead
Core wire and the bead center line of each single bead
Connect the bead center line of the common bead section to each other
A triangular flat portion surrounded by the following bead center line is formed, and each of the inner borders is formed from each of the bead center lines.
The metal gasket according to claim 1, wherein a length of a perpendicular to each of the arc-shaped inner borders is substantially the same. 8. The arc-shaped outer border according to claim 1, wherein the arc-shaped outer border is formed outside the outer border and has a center on an extension of a center line of the common bead portion. Metal gasket.