JP2000035134A - Metal gasket - Google Patents

Abstract

PROBLEM TO BE SOLVED: To reduce nonuniformity of bearing distribution around a hole for a cylinder. SOLUTION: An auxiliary plate 10 to be accumulated on a metallic base plate is constituted by connecting an inside part 10A forming a part to surround a hole 10a for a cylinder and an outside part 10B forming a remaining part within a horizontal surface. A boundary line of the inside part 10A and the outside part 10B is made so that at least a region of the base plate to be overlapped with a bead is included in the inside part 10A. Additionally, plate width around the hole 10a for the cylinder of the inside part 10A is made narrow at a position near a straight line passing a center O of the hole 10a for the cylinder and a center of a bolt hole 10c and wider as it parts from there in the peripheral direction.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a metal gasket interposed between a cylinder block and a cylinder head constituting an internal combustion engine to prevent leakage of fluid such as combustion gas, cooling water, lubricating oil and the like. In particular, in a metal gasket having a metal substrate and a sub-plate, the nonuniformity of the surface pressure distribution around the cylinder hole is reduced.

[0002]

2. Description of the Related Art As a conventional metal gasket, for example, there is a metal gasket disclosed in Japanese Patent Application Laid-Open No. 7-243531.

[0003] That is, the metal gasket disclosed in this publication has a configuration in which a metal sub-plate is sandwiched between two metal substrates, and the sub-plate appropriately covers a peripheral portion of a cylinder hole. A thick metal plate surrounding the opening and a thin metal plate that forms a part other than the metal plate surrounding the opening are laser-welded to each other. Are formed by bonding with each other. The sub-plate is sandwiched between the substrates so that the peak of the bead formed on the peripheral portion of the cylinder hole of each substrate hits the thick plate portion of the sub-plate. As a result, the sealing performance is improved.

In other words, the thickness of the sub-plate is increased at the peripheral portion of the cylinder hole and reduced at other portions, so that when the bolt is fastened, the surface pressure of the peripheral portion of the cylinder hole is higher than that of the other portions. And the surface pressure is concentrated on the peak of the bead, and there is no danger that the hem of the bead will escape from the thick part of the sub-plate, and furthermore, the thick plate and the thin plate constituting the sub-plate are welded by laser welding There is no displacement as a unit, and no gap is formed in that part, so that the sealing performance is improved.

[0005]

However, in the above-mentioned conventional metal gasket, since the auxiliary plate is formed of two types of metal plates having different thicknesses, the above effects can be expected. When applied to the latest internal combustion engines that have been developed or are being developed in recent years, it is not possible to sufficiently reduce the unevenness of the surface pressure distribution that occurs when bolts are fastened, and it is hoped that the sealing performance will be further improved. It is rare.

[0006] In other words, vehicle engines and the like that have been or are being developed in recent years have been reduced in size and weight, increased in output, and saved in fuel to achieve higher performance. In order to satisfy the above, there is a tendency that a lightweight aluminum alloy is used for each member constituting the engine, and the interval between adjacent cylinders in the cylinder block is formed as narrow as possible. However, when each member is formed using an aluminum alloy, the overall rigidity is significantly reduced as compared with, for example, a case using cast iron. In addition, since the heat capacity of each member of the engine is reduced due to the reduction in size and weight of the engine, the cooling water passage is expanded, and the overall rigidity of the engine also tends to decrease. Furthermore, in order to improve the cooling efficiency, the cooling water passage is formed near the cylinder, but by this, the tightening portion of the bolt for tightening the cylinder block and the cylinder head is formed at a position away from the cylinder. ,
As a result, the tightening force is large at a position close to the bolt, and conversely, is small at a position far from the bolt.

As described above, when the overall rigidity of the engine decreases and the deviation of the tightening force by the bolts increases, that is, the unevenness of the surface pressure distribution becomes remarkable, the cylinder gas at the edge of the cylinder hole of the metal gasket is This increases the possibility that a large gap difference occurs between the block and the cylinder head.

Particularly, in the case of the metal gasket disclosed in the above-mentioned publication, the width of the thick plate portion of the sub plate (the plate width around the hole for the cylinder) is not particularly changed, so that it is used for an engine having low rigidity. At the time of bolt fastening, the amount of deformation of the cylinder head tends to be large in a portion close to a straight line connecting the centers of the cylinder hole and the bolt hole, and the amount of deformation of the cylinder head tends to be small in a portion far from the straight line. In other words, the sub-plate has a plate thickness difference that the portion near the cylinder hole is thick and the portion far from the cylinder hole is thin. As a result, when the bolt is tightened, the portion around the thick cylinder hole first becomes the cylinder block. Between the cylinder head and the cylinder head, and further tighten the bolts from that state,
Since the surface pressure around the bolt hole is high, even the thin part is sandwiched between the cylinder block and the cylinder head, and at that time, the step between the thick part and the thin part of the sub plate is removed. As a fulcrum, the cylinder head is deformed, and the angle of the deformation is large in a portion close to a straight line connecting the centers of the cylinder holes and the bolt holes, and is small in a portion far from the straight line.

Further, the metal gasket disclosed in the above publication has a disadvantage that the production cost is increased because the two metal plates constituting the sub-plate are joined by laser welding. In addition, since laser welding is a welding method that locally raises the temperature of a portion to be welded to an extremely high temperature, the temperature difference between the portion to be welded and its surrounding portion is large, so that a large thermal distortion remains, The possibility of destruction due to vibration during engine operation cannot be ruled out.

The present invention has been made in view of such an unsolved problem of the prior art, and has a sub-plate composed of a thick portion around a cylinder hole and other thin portions. It is an object of the present invention to further reduce the non-uniformity of the surface pressure distribution at the time of bolt fastening and to reduce the manufacturing cost of such a sub-plate in a metal gasket provided with:

[0011]

In order to achieve the above object, the invention according to claim 1 is a bead having a hole for a cylinder and a bolt hole and being continuous in a circumferential direction so as to surround the hole for a cylinder. Formed at least one metal substrate and a sub-plate having a cylinder hole and a bolt hole,
The sub-plate is laminated so that the positions of the cylinder hole and the bolt hole coincide with each other, and the sub-plate includes an inner portion forming a peripheral portion of the cylinder hole including at least a region overlapping the bead, An outer portion forming an outer portion than the outer portion, and a metal gasket configured by combining plate materials having different thicknesses so that the thickness of the inner portion is greater than the thickness of the outer portion. The width of the plate around the cylinder hole of the inner portion is close to a straight line connecting the centers of the cylinder hole and the bolt hole so that the unevenness of the surface pressure distribution generated at the time of bolt fastening is reduced. The portion was narrower and the portion farther from the straight line was wider.

According to a second aspect of the present invention, in the metal gasket according to the first aspect of the present invention, the thickness of the inner portion is adjusted so that non-uniformity of surface pressure distribution generated at the time of bolt fastening is reduced. In addition, the portion near the straight line is thin,
The portion far from the straight line was thickened.

According to a third aspect of the present invention, in the metal gasket according to the first or second aspect,
The thickness of the inner portion is thicker on the cylinder hole side,
On the side far from the cylinder hole, the thickness was reduced.

Further, according to a fourth aspect of the present invention, in the metal gasket according to the first to third aspects of the present invention, the metal gasket is recessed at a predetermined position on the outer peripheral portion of the plate material forming the inner portion inward of the plate material. A concave portion is formed, and a convex portion that fits with the concave portion is formed on the inner peripheral portion of the outer portion. When the concave portion and the convex portion are fitted, the inner edge portion of the concave portion is formed with the convex portion. By deforming so as to protrude above the part, the plate material forming the inner part and the plate material forming the outer part were joined.

In order to achieve the above object, the invention according to claim 5 is directed to at least one of a plurality of circumferentially continuous beads having a cylinder hole and a bolt hole and surrounding the cylinder hole. A metal substrate and a sub-plate having a cylinder hole and a bolt hole are laminated so that the positions of the cylinder hole and the bolt hole coincide with each other, and the sub-plate has at least the bead and An inner portion forming a peripheral portion of the cylinder hole including an overlapping region, and an outer portion forming an outer portion than the inner portion, wherein the thickness of the inner portion is greater than the thickness of the outer portion. In order to increase the thickness, in a metal gasket configured by combining plate materials having different plate thicknesses, the plate thickness of the inner portion is reduced so that non-uniformity of surface pressure distribution generated at the time of bolt fastening is reduced. Thin at a portion close to the serial straight and thick at a portion far from the straight line.

In order to achieve the above object, the invention according to claim 6 is directed to at least one of a cylinder-shaped hole and a bolt hole, wherein at least one circumferentially continuous bead is formed so as to surround the cylinder hole. A metal substrate and a sub-plate having a cylinder hole and a bolt hole are laminated so that the positions of the cylinder hole and the bolt hole coincide with each other, and the sub-plate has at least the bead and An inner portion forming a peripheral portion of the cylinder hole including an overlapping region, and an outer portion forming an outer portion than the inner portion, wherein the thickness of the inner portion is greater than the thickness of the outer portion. In a metal gasket configured by combining plate materials having different plate thicknesses so as to be thicker, the plate thickness of the inner portion is thicker on the cylinder hole side and is larger on the side farther from the cylinder hole. Kushida.

In order to achieve the above object, the invention according to claim 7 is directed to at least one of a plurality of beads having a cylinder hole and a bolt hole and having a circumferentially continuous bead formed so as to surround the cylinder hole. A metal substrate and a sub-plate having a cylinder hole and a bolt hole are laminated so that the positions of the cylinder hole and the bolt hole coincide with each other, and the sub-plate has at least the bead and An inner portion forming a peripheral portion of the cylinder hole including an overlapping region, and an outer portion forming an outer portion than the inner portion, wherein the thickness of the inner portion is greater than the thickness of the outer portion. In a metal gasket configured by combining plate members having different plate thicknesses so as to be thicker, a concave portion recessed inward of the plate member is provided at a predetermined position on the outer peripheral portion of the plate member forming the inner portion. While forming, a convex portion that fits with the concave portion is formed on the inner peripheral portion of the outer portion, and the inner edge portion of the concave portion is placed on the convex portion in a state where the concave portion and the convex portion are fitted. By deforming so as to protrude, the plate material forming the inner portion and the plate material forming the outer portion were joined.

According to the first aspect of the present invention, the width of the plate around the cylinder hole of the inner portion constituting the sub plate is set to be smaller than the straight line connecting the centers of the cylinder hole and the bolt hole. Since it is positively changed so that it becomes wider at narrow and distant parts, even if the cylinder head is deformed with the step between the inner part and the outer part of the sub plate as a fulcrum at the time of bolt fastening, the cylinder hole and the bolt hole The difference between the deformation angle of the cylinder head near the straight line connecting the centers of the cylinder head and the deformation angle of the cylinder head far from the straight line is smaller than before, and the unevenness of the surface pressure distribution is reduced accordingly I will be.

According to the second aspect of the present invention, the thickness of the inner portion of the sub-plate is made thinner in a portion near a line connecting the center lines of the cylinder holes and the bolt holes, and thicker in a far portion. In addition, since the inflection is applied in the direction along the edge of the cylinder hole, even when the cylinder head is deformed around the step between the inner part and the outer part of the sub-plate at the time of bolt fastening, the surface pressure is high. As a result, the fulcrum is low in a position where the surface pressure is likely to be low, and conversely, the fulcrum is high in a portion where the surface pressure is easily lowered.
As compared with the conventional case where the height of the fulcrum is constant, the non-uniformity of the surface pressure distribution is reduced accordingly, and the non-uniformity of the surface pressure distribution is further reduced in combination with the invention according to claim 1. I will be.

According to the third aspect of the present invention, the thickness of the inner portion of the sub-plate is set so as to be thicker on the cylinder hole side and thinner on the outer peripheral side along the radiation centered on the cylinder hole. The difference in the direction
Even if the cylinder head is deformed with the step between the inner part and the outer part of the sub-plate as a fulcrum, the thickness of the sub-plate is adjusted in a direction that matches the deformation of the cylinder head. The surface pressure difference between the inner peripheral side and the outer peripheral side of the inner portion of the sub-plate is smaller than in the conventional case where the thickness is constant.
As a result, the range of functioning as a seal is widened and stable sealing performance is obtained, and the high-performance metal is combined with the invention according to claim 1 or 2 wherein unevenness of surface pressure distribution is achieved. It becomes a gasket.

Further, according to the fourth aspect of the present invention, the concave portion formed on the outer peripheral portion of the plate material constituting the inner portion of the sub-plate and the inner peripheral portion of the plate material constituting the outer portion of the sub-plate are formed. The convex part is fitted in such a way that the pieces of the jigsaw puzzle fit together, and in this fitted state, the inner edge of the concave part is deformed so as to protrude above the convex part, and the concave part and the convex part are integrated. Since the inner part and the outer part are joined as a welding work such as laser welding in the manufacturing process of the sub-plate is unnecessary, and in addition to the effects of the invention according to claims 1 to 3, cost reduction and the like can be achieved. It will be planned.

On the other hand, in the invention according to claim 5, the thickness of the inner portion of the sub-plate is thin near the line connecting the center lines of the cylinder hole and the bolt hole and thin at the far portion. As described above, since the inflection is applied in the direction along the edge of the cylinder hole, even when the cylinder head is deformed around the step between the inner part and the outer part of the sub-plate at the time of bolt fastening, the surface pressure is reduced. The fulcrum is low in the position where it is likely to be high, and conversely the fulcrum is high in the part where the surface pressure is apt to be low. Is reduced.

Further, in the invention according to claim 6, the thickness of the inner portion of the sub-plate is adjusted to the radiation centered on the cylinder hole so that the thickness is larger on the cylinder hole side and thinner on the outer peripheral side. Since the thickness is made different in the direction along the cylinder head, even if the cylinder head is deformed with the step between the inner part and the outer part of the sub-plate as a fulcrum at the time of bolt fastening, in the direction matching the deformation of the cylinder head Since the thickness of the sub-plate is adjusted, the surface pressure difference between the inner peripheral side and the outer peripheral side of the inner part of the sub-plate is smaller than in the conventional case where the thickness of the sub-plate is constant. Become. As a result, the range of functioning as a seal is expanded, and stable sealing performance is obtained.

Furthermore, in the invention according to claim 7,
By the same operation as the invention according to the fourth aspect, welding work such as laser welding is not required in the manufacturing process of the sub-plate.

[0025]

Embodiments of the present invention will be described below with reference to the drawings. 1 to 11 are views showing an embodiment of the present invention. FIG. 1 is a partially cutaway plan view of a sub-plate 10 constituting a metal gasket 1 according to the present invention.
When the metal gasket 1 with the sub-plate 10 sandwiched between two metal substrates 2 and 3 is interposed between the cylinder block 4 and the cylinder head 5 of the engine, the bolt is not fastened. FIG. 4 is a partial cross-sectional view showing the positional relationship of FIG.

First, the overall structure of the metal gasket 1 will be briefly described with reference to FIG. 2. The metal gasket 1 is interposed between the mutually opposing deck surfaces 4A and 5A of the cylinder block 4 and the cylinder head 5. It seals between both deck surfaces 4A and 5A. The cylinder block 4 includes a cylinder 4a, a water hole 4b, a bolt hole 4c, and an oil hole 4d.
Are formed in place. The cylinder head 5 is also provided with a cylinder 5 corresponding to the configuration of the cylinder block 4.
a, a water hole 5b, a bolt hole 5c, an oil hole 5d, and the like are formed at appropriate places. In FIG. 2, O is the center of the cylinder 4a.

Cylinder block 4 and cylinder head 5
Is formed of, for example, an aluminum alloy, but a portion of the cylinder block 4 forming the cylinder 4a includes:
A cast iron sleeve 4e for forming the inner peripheral wall surface of the cylinder 4a is mounted. In this example, the entire outer peripheral surface of the cast iron sleeve 4e is covered with the aluminum alloy forming the main body of the cylinder block 4. However, only the lower end (not shown) of the cast iron sleeve 4e is covered with the cylinder block. 4 and a large part of the outer peripheral surface of the cast iron sleeve 4 is provided with a water hole 4 such as a water jacket.
b may be directly defined.

The two substrates 2 and 3 among the plate members constituting the metal gasket 1 are plane-symmetric members whose upside down shapes are upside down, and each of the substrates 2 and 3 has a cylinder 4a. Circumferentially continuous beads 2A and 3 so as to surround
A, and mountain-shaped projections 2B, 3B for sealing the water hole 4b and the oil hole 4d. The substrates 2 and 3 have cylinder holes 2a and 3a corresponding to the cylinders 4a and the like.
a, water passage hole (not shown in FIG. 2), bolt hole 2
c, 3c and oil passage holes 2d, 3d are formed at appropriate places.

On the other hand, similarly to the substrates 2 and 3, the sub-plate 10 is provided with a cylinder hole 10a, a water passage hole 10b (not shown in FIG. 2), a bolt hole 10c, and an oil passage hole 10d. And the cylinder holes 2a, 3a, 10a
The metal gasket 1 is formed by sandwiching the sub-plate 10 between the substrates 2 and 3 so that the positions such as coincide with each other.

Here, the sub-plate 10 is a member made of soft metal which is thicker than the substrates 2 and 3, and forms a portion surrounding the periphery of the cylinder hole 10a as shown in FIG. The inner part 10A and the outer part 10B forming the remaining part are connected in a horizontal plane. In FIG. 1, the beads 2a, 3a of the substrates 2, 3
Indicates the trajectory of the vertex in the line L ₁ of the one-dot chain line, also shows the trajectory of both the inner wall of the water hole 4b of the cylinder block 4 by the line L _2, L ₃ of the two-dot chain line.

The structure of the sub-plate 10 will be described in more detail. A plurality of cylinder holes 10a are formed in the sub-plate 10 in such a manner that their centers are aligned on a straight line, corresponding to the cylinders 4a of the cylinder block 4. And cylinder block 4
A plurality of water passage holes 10b are formed at appropriate places corresponding to the water holes 4b.

A plurality of bolt holes 10c are formed further outside the water passage hole 10b so as to be located at four vertices of a rectangle concentric with the respective cylinder holes 10a. In this example, since a plurality of cylinder holes 10a are provided in one row, four bolt holes 10c surrounding one cylinder hole 10a from four directions and another adjacent cylinder hole 10c are formed.
Of the four bolt holes 10c that surrounds a from four directions, two bolt holes 10c located between the two cylinder holes 10a are common. Bolt hole 10c
An oil passage hole 10d is formed at an appropriate place outside the oil passage.

The above-described inner portion 10A and outer portion 10
The boundary of B is at least the beads 2a, 3a of the substrates 2, 3.
Is included in the inner portion 10A, and the outer line of the inner region 10A is the outer line L of the water hole 4b.
It is decided to pass inside than ₃ .

As shown in FIG. 3, which is a partially broken plan view of the inner portion 10A, the plate width around the cylinder hole 10a of the inner portion 10A is set at the center O of the cylinder hole 10a.
And narrow at a position close to a straight line M passing through the center of the bolt hole 10c, widens with distance therefrom in the circumferential direction, so as to overlap substantially in line L ₃ with a straight line N near shifted 45 degrees from the straight line M. However, actually, the water passage hole 10b
Are formed everywhere, so that the water passage hole 10b,
In a portion where the boundary between the inner portion 10A and the outer portion 10B intersects, the outer peripheral shape of the inner portion 10A is complicated. For the same reason, as shown in FIG. 4 which is a partially broken plan view of the outer portion 10B, the portion where the boundary between the inner portion 10A and the outer portion 10B intersects the outer portion 10B.
Has an intricate inner peripheral shape.

The plate thickness of the inner portion 10A varies along the circumferential direction of the cylinder hole 10a so that the portion near the straight line M is thinner and the portion near the straight line N is thicker. That is, the inner part 10A around the cylinder hole 10a
As shown in FIG. 5, the thickness of the inner portion 10A is the thickest at the position of the straight line N, gradually decreases as the position approaches the straight line M, and becomes the thinnest at the position of the straight line M.

Further, as shown in FIG. 5, the thickness of the inner portion 10A is changed not only along the circumferential direction of the cylinder hole 10a but also along the width direction.

Here, as shown in FIG. 6 in which the deformation of the cylinder head 5 with respect to the deck surface 5A at the position along the line AA in FIG.
The deck surface 5A is pressed against the deck surface 4A by applying a force to the bolt fastening position BT. The inner surface 1 of the sub-plate of the metal gasket 1 is located between the deck surfaces 4A and 5A.
If the bolt is further tightened even after 0A is sandwiched, a portion outside the step between the inner portion 10A and the outer portion 10B tends to further approach the deck surface 4A side. 5A is deformed,
As shown in FIG. 6, the shape becomes such that the center O is higher than the end. FIG. 6A shows the cylinder head 5.
FIG. 6B shows a case where the rigidity of the cylinder head 5 is low. FIG.
Portions indicated by hatching in (a) and (b) are cross sections of the inner portion 10 </ b> A of the sub-plate 10.

On the other hand, as shown in FIG. 7 in which the deformation of the cylinder head 5 with respect to the deck surface 5A at a position along the line BB in FIG. When the bolts are fastened, the center O is deformed into a shape in which the center O rises more than the end. However, since it is far from the bolt, the amount of deformation is smaller than that shown in FIG. The hatched portion in FIG. 7 is a cross section of the inner portion 10 </ b> A of the sub-plate 10.

Accordingly, the angle of deformation of the deck surface 5A at the time of bolt fastening with the above-mentioned step as a fulcrum becomes steep at a position close to the bolt (position close to the straight line M) in the circumferential direction, and becomes distant from the bolt (line N). (Position close to).

The difference in the deformation angle is due to the cylinder hole 10.
This is one of the factors that cause the non-uniformity of the surface pressure distribution around the area a. In order to alleviate this, in the present embodiment, first, the cylinder hole 10
Secondly, the width of the plate around "a" is varied, and second, the plate thickness of the inner portion 10A is varied along the circumferential direction of the cylinder hole 10a. Further, in order to prevent a decrease in sealing performance due to the deformation angle, the inner portion 10 is formed.
The thickness of A is different between its inner and outer circumferences.

That is, the cylinder hole 10 of the inner portion 10A
If the width of the plate around a is given the width as described above, the step between the inner portion 10A and the outer portion 10B, which is a fulcrum when the deck surface 5A is deformed, is a portion where the surface pressure is likely to increase (in the vicinity of the straight line M). In the portion near the cylinder hole 10a, the portion where the surface pressure is likely to decrease (in the vicinity of the straight line N) is the cylinder hole 10a.
Since it is far from a, the difference in the angle of deformation of the deck surface 5A with the step as a fulcrum is reduced, and the unevenness of the surface pressure is reduced.

Further, as shown in FIG.
Is changed along the circumferential direction of the cylinder hole 10a, the portion of the inner portion 10A where the surface pressure is likely to be low (near the straight line N) is the portion where the surface pressure is likely to be high (the straight line). (Near M) before being sandwiched between the deck surfaces 4A and 5A, which also reduces the non-uniformity of the surface pressure.

[0043] Further, in FIG. 8 (a) the thickness change of the inner part 10A shown in C ₁ of FIG. 6 (a), FIG plate thickness change of the inner part 10A shown in C ₂ in FIG. 6 (b) 8 (b), the show in FIGS 8 (c) the thickness change of the inner part 10A shown in C ₃ in FIG. 7, at any position, the plate thickness of the inner portion,
In order to match the deformation of the deck surface 5A at each position with the step as a fulcrum, the inner surface is thicker and the outer surface is thinner so that a deformation angle with the step of the deck surface 5A as a fulcrum occurs. Also, the tendency that the inner surface pressure is lower than the outer surface pressure is reduced, and stable sealing performance can be obtained. Although shown in FIG. 8 (d) the thickness change of the inner part 10A shown in C ₄ in FIG. 7, this is because it is between two adjacent cylinder bore 10a, the thickness is constant .

As described above, in the present embodiment, since the width and thickness of the inner portion 10A are appropriately changed,
The non-uniformity of the surface pressure around the cylinder hole 10a can be greatly reduced, and as a result, the cylinder 4a
Can be greatly improved, and the sealing performance is also improved, so that a high-performance metal gasket 1 can be obtained.

The optimum values of the width and thickness of the inner portion 10A are determined by the sub-plate 1 having the same width and thickness of the inner portion 10A.
The metal gasket 1 constituted by using 0 is interposed between the cylinder block 4 and the cylinder head 5, and in that state, a surface pressure distribution measurement around the cylinder 4a and a lead bullet test are performed, and a detailed selection is made based on the result. It is desirable.

Next, the connection structure of the inner portion 10A and the outer portion 10B of the sub-plate 10 will be described. That is, as shown in FIGS. 1 and 3, of the outer peripheral surface of the inner portion 10 </ b> A,
At a position that intersects a straight line N orthogonal to a line connecting the centers O of the cylinder holes 10a, a concave portion 1 having a substantially circular shape is provided.
1 is formed. On the other hand, as shown in FIGS. 1 and 4, a convex portion 12 that fits into the concave portion 11 is formed on the inner peripheral surface of the outer portion 10B. In the present embodiment, each of the concave portion 11 and the convex portion 12 is formed twice as many as the number of the cylinder holes 10a.

[0047] An enlarged view of a C ₅ parts of FIG. 1 in FIG. 9, FIG. 10 to D-D line cross-sectional view of FIG. 9, shown in FIGS. 11 to line E-E sectional view of FIG. Then, the concave portion 11 and the convex portion 12
When the inner part 10A and the outer part 10B are formed by punching out a plate material, they have substantially the same shape so that they can be fitted from a direction perpendicular to the surface of the plate material. For this reason, if the inner part 10A and the outer part 10B are combined from a direction perpendicular to the plane so that the convex part 12 fits into the concave part 11, the inner part 10A and the outer part 10B will be integrated for the time being. However, they are easily separated as they are. Therefore, the center in the thickness direction of the inner portion 10A and the outer portion 10B coincide with each other,
With the concave portion 11 and the convex portion 12 fitted together, the concave portion 11
By pressing the fitting portion of the convex portion 12 from the front and back surfaces with a jig whose tip end surface is slightly larger than the concave portion 11 and applying pressure, the inner edge portion of the concave portion 11 is deformed and the step portion 11a is formed. To form Then, the step 11
As a result, the inner edge portion of the concave portion 11 protrudes above the convex portion 12, and the protruding portion sandwiches the convex portion 12 from above and below, resulting in the concave portion 11 and the convex portion 1.
2 can not be easily separated in the front and back direction,
Thereby, the inner part 10A and the outer part 10B are joined to form the sub-plate 10.

As described above, the structure in which the inner portion 10A and the outer portion 10B are integrated by using the concave portion 11 and the convex portion 12 greatly reduces the manufacturing cost as compared with the case where they are integrated by laser welding or the like. Can be reduced,
Since no thermal distortion remains, the possibility that the sub-plate 10 is broken by vibration during operation of the engine is significantly reduced.

Further, since the inner edge portion of the concave portion 11 projects over the convex portion 12, the concave portion 11 and the convex portion 12 are formed.
Does not increase the thickness of the joint portion.
Therefore, since the thickness of the metal gasket 1 does not increase so much, there is an advantage that the positions where the concave portions 11 and the convex portions 12 are formed are not particularly limited. That is, the concave portion 11 and the convex portion 12 do not have to be formed in accordance with the position of the water hole 4b.

If the recess 11 is formed in the inner member 10A, it is not necessary to increase the size of the original plate for punching the inner member 10A due to the formation of the recess 11. There is no effect on costs. Note that the outer member 10B is formed by punching out the portion where the inner member 10A is fitted from the plate material of the book in the first place. Therefore, forming the convex portion 12 does not affect the material cost.

The beads 2A formed on the substrates 2 and 3
The sealing action by the 3A, the mountain-shaped projections 2B, 3B and the like is the same as that of a known metal gasket. Further, in the above embodiment, the metal gasket 1 has the configuration in which the sub-plate 10 is sandwiched between the two substrates 2 and 3 with the vertices of the beads 2A and 3A facing outward, but is not limited thereto. Instead, as shown in FIG. 12A, the sub-plate 1 is placed between the two substrates 2 and 3 with the vertices of the beads 2A and 3A facing inward.
0 or a bead 2
One of A and 3A may be directed outward and the other may be directed inward. Further, the number of the substrates 2 and 3 is not limited to two, and the metal gasket 1 may be formed by laminating one substrate 2 and the sub-plate 10 as shown in FIG. Good.

In the above embodiment, as described with reference to FIGS. 9 to 11, the inner edge of the concave portion 11 is deformed by pressing with a jig. However, the present invention is not limited to this. For example, FIG. 1 is a sectional view similar to FIG.
As shown in FIG. 3, the inner portion 10 extends along the inner edge of the recess 11.
While forming a V-shaped cut 13 on the surface A,
May protrude over the convex portion 12.

Further, in the above embodiment, the concave portion 11 and the convex portion 12 are substantially circular, but the present invention is not limited to this. For example, as shown in FIG. 14, which is an enlarged view similar to FIG. The concave portion 11 may have a trapezoidal shape in which the inside is wider than the opening side, and the convex portion 12 may have a similar trapezoidal shape in which the distal end side is wider than the base end side. In this case, it is desirable that the shape of the tip of the jig for forming the step portion 11 a be a rectangle slightly larger than the recess 11. Also, this recess 1
The number of fitting portions including the one and the convex portion 12 is not limited to two per cylinder, and the number thereof is arbitrary. Then, the formation position of each fitting portion is determined by the hole 10 for the cylinder.
If the shape of the fitting portion is not symmetrical with respect to the line connecting the centers O of a, or different from the shape of the fitting portion at the position symmetrical with respect to the line connecting the centers O, An error in the combination direction of the portion 10A and the outer portion 10B can be reliably prevented.

In the above embodiment, the width of the inner portion 10A of the sub-plate 10 is set to be inner than the outer shape of the water hole 4b. However, the present invention is not limited to this. In order to do so, the plate width may be widened outside the water hole 4b.

[0055]

As described above, claims 1, 2, 5
According to the invention according to the invention, since the width and thickness of the inner portion constituting the sub-plate are appropriately selected, the unevenness of the surface pressure around the cylinder can be reduced, and the circularity of the cylinder can be reduced. Has the effect of greatly improving

According to the third and sixth aspects of the present invention,
There is an effect that the sealing performance is improved. Further, according to the fourth and seventh aspects of the invention, there is an effect that the manufacturing cost can be reduced and the possibility that the sub-plate is broken can be reduced.

[Brief description of the drawings]

FIG. 1 is a partially broken plan view of a sub-plate.

FIG. 2 is a partial cross-sectional view illustrating a usage state of a metal gasket.

FIG. 3 is a partially broken plan view of an inner portion of a sub-plate.

FIG. 4 is a partially broken plan view of an outer portion of a sub-plate.

FIG. 5 is a diagram showing a change in plate thickness around a cylinder hole in an inner portion of a sub plate.

FIG. 6 is a view for explaining deformation of the cylinder head along the line AA in FIG. 1;

FIG. 7 is a view for explaining deformation of the cylinder head along the line BB in FIG. 1;

FIG. 8 is a diagram showing a change in the thickness of the inner portion of the sub-plate in the width direction.

9 is an enlarged view of a C ₅ parts of FIG.

FIG. 10 is a sectional view taken along line DD of FIG. 9;

FIG. 11 is a sectional view taken along line EE of FIG. 9;

FIG. 12 is a sectional view showing another example of the metal gasket.

FIG. 13 is a view showing a modified example of a connecting portion between an inner portion and an outer portion of a sub-plate.

FIG. 14 is a view showing a modified example of a connecting portion between an inner portion and an outer portion of a sub-plate.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Metal gasket 2, 3 Substrate 4 Cylinder block 5 Cylinder head 10 Subplate 10A Inside part 10B Outside part 10a Cylinder hole 10c Bolt hole 11 Concave part 12 Convex part

Claims (7)

[Claims] At least one metal substrate having a cylinder hole and a bolt hole and having a circumferentially continuous bead surrounding the cylinder hole, and a cylinder hole and a bolt hole. And a sub-plate having the following configuration. The sub-plate forms a peripheral portion of the cylinder hole including at least a region overlapping the bead. An inner portion and an outer portion forming an outer portion of the inner portion are provided, and plate materials having different thicknesses are combined so that the inner portion has a greater thickness than the outer portion. In the metal gasket thus configured, the plate width of the inner portion around the cylinder hole is adjusted so that the unevenness of the surface pressure distribution generated at the time of bolt fastening is reduced. Narrow at a portion close to a straight line connecting the centers of the bets holes, metal gasket, characterized in that it has widely distant portion from the straight line. 2. The thickness of the inner portion is thinner at a portion close to the straight line and thicker at a portion far from the straight line so as to reduce unevenness in surface pressure distribution generated at the time of bolt fastening. The described metal gasket. 3. The metal gasket according to claim 1, wherein a plate thickness of the inner portion is thicker on the cylinder hole side and thinner on a side farther from the cylinder hole. 4. A concave portion which is recessed in an inward direction of the plate material at a predetermined position on an outer peripheral portion of the plate material constituting the inner portion, and a convex portion which fits with the concave portion is formed on an inner peripheral portion of the outer portion. Forming a portion and deforming the inner edge portion of the concave portion so as to protrude above the convex portion in a state where the concave portion and the convex portion are fitted to each other, so that the plate member constituting the inner portion and the outer portion are formed. The metal gasket according to any one of claims 1 to 3, wherein the metal gasket is combined with a plate material constituting the metal gasket. 5. At least one metal substrate having a cylinder hole and a bolt hole and having a circumferentially continuous bead surrounding the cylinder hole, and a cylinder hole and a bolt hole. And a sub-plate having the following configuration. The sub-plate forms a peripheral portion of the cylinder hole including at least a region overlapping the bead. An inner portion and an outer portion forming an outer portion of the inner portion are provided, and plate materials having different thicknesses are combined so that the inner portion has a greater thickness than the outer portion. In the metal gasket that is configured, the thickness of the inner portion is thinner at a portion close to the straight line and farther from the straight line so that unevenness of surface pressure distribution generated at the time of bolt fastening is reduced. In thicker metal gasket, characterized in that the. 6. At least one metal substrate having a cylinder hole and a bolt hole and having a circumferentially continuous bead surrounding the cylinder hole, and a cylinder hole and a bolt hole. And a sub-plate having the following configuration. The sub-plate forms a peripheral portion of the cylinder hole including at least a region overlapping the bead. An inner portion and an outer portion forming an outer portion of the inner portion are provided, and plate materials having different thicknesses are combined so that the inner portion has a greater thickness than the outer portion. In the metal gasket thus configured, the plate thickness of the inner portion is thicker on the cylinder hole side,
A metal gasket characterized by being thinner on a side far from the cylinder hole. 7. At least one metal substrate having a cylinder hole and a bolt hole, and having a circumferentially continuous bead surrounding the cylinder hole, and a cylinder hole and a bolt hole. And a sub-plate having the following configuration. The sub-plate forms a peripheral portion of the cylinder hole including at least a region overlapping the bead. An inner portion and an outer portion forming an outer portion of the inner portion are provided, and plate materials having different thicknesses are combined so that the inner portion has a greater thickness than the outer portion. In the metal gasket that is configured, a concave portion that is recessed in the inward direction of the plate material is formed at a predetermined position on the outer peripheral portion of the plate material that forms the inner portion, and the inner peripheral portion of the outer portion has the concave portion. The inner part is formed by forming a convex part to be fitted with the part and deforming the inner edge part of the concave part so as to protrude above the convex part in a state where the concave part and the convex part are fitted. A metal gasket characterized by combining a plate material to be formed and a plate material constituting the outer portion.