JP2000028001A - Metal gasket - Google Patents

Abstract

PROBLEM TO BE SOLVED: To reduce manufacturing cost of a metal gasket capable of securing roundness around a cylinder by making surface pressure uniform compaired without cost of a conventional technique. SOLUTION: This metal gasket 10 is the one that a metallic substrate 1 and an edge plate 2 increasing seal pressure around a cylinder are laminated. A seal width around the cylinder by the edge plate 2 is made narrow near a bolt hole 12 in which surface pressure generated at the time of tightening a bolt becomes high and is made wide between the bolt hole 12 and the bolt hole 12 in which surface pressure becomes low.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a metal gasket, and more particularly, to a metal gasket interposed at a joint surface between a cylinder block and a cylinder head of an internal combustion engine to prevent leakage of fluid such as combustion gas, cooling water and lubricating oil. Metal gasket to prevent.

[0002]

2. Description of the Related Art In general, a joint surface between a cylinder block constituting an automobile engine or other internal combustion engine and a cylinder head mounted thereon is provided with a fluid such as combustion gas, cooling water, lubricating oil or the like from the joint surface. In order to prevent leakage, a gasket is interposed, and both are fastened with fasteners such as bolts to provide a sealing function. Such a gasket is rich in heat resistance, compression resistance, and durability,
Metal gaskets having good resilience (spring properties) and thermal conductivity are widely used.

[0003] In recent years, in order to achieve higher performance of engines, developments such as miniaturization, weight reduction, high output, and fuel saving have been advanced. To achieve these,
An aluminum alloy is used for each member constituting the engine, and the interval between adjacent cylinders in the cylinder block tends to be formed as narrow as possible.

On the other hand, when an engine member is formed using an aluminum alloy as described above, the overall rigidity is significantly reduced as compared with a case where the engine member is formed using, for example, cast iron. Further, as a new inconvenience caused by downsizing and lightening of the engine, an increase in the amount of heat generated by the operation of the engine is raised, and as a countermeasure, the cooling water channel is expanded. As a result, the overall rigidity of the engine is further reduced.

Further, the cooling water passage is formed near the cylinder in order to improve the cooling efficiency, whereby a tightening portion such as a bolt for tightening the cylinder block and the cylinder head is formed at a position away from the cylinder. Will be done. Then, the tightening force is large at a position close to the bolt, and conversely, the tightening force is small at a position far from the bolt.

[0006] As described above, when the overall rigidity of the engine is reduced and the deviation of the tightening force of the fastener such as a bolt is increased, the metal gasket interposed between the joint surfaces becomes
At the end of the cylinder hole opened corresponding to the cylinder, an extremely small gap is generated between the cylinder block and the cylinder head. When such a phenomenon occurs, the surface pressure becomes unbalanced around the cylinder hole, and the roundness of the cylinder hole is impaired. Also, when the engine is running, the heat conduction from the cylinder block to the cylinder head is partially different,
Deformation of the cylinder is promoted.

Further, when the gap is generated, the joining surface side of the metal gasket is directly exposed to the combustion gas, and the life of the metal gasket is shortened, and the sealing property cannot be ensured for a long time. obtain.

Therefore, conventionally, a bead is formed along the circumferential direction of the cylinder hole at the peripheral portion of the cylinder hole of the substrate of the metal gasket, and the bead is elastically deformed by the tightening force of the bolt. In order to prevent the gap from occurring, a measure is taken by providing a sealing function by the elastic restoring force of the above. Further, in order to prevent the bead from being plastically deformed to deteriorate the sealing property, a stopper for limiting the deformation of the bead is provided on the cylinder hole side of the bead.

Further, from the deviation of the tightening force, the surface pressure distribution on the connecting surface between the cylinder block and the cylinder head is high at the fastening position of the fastening bolt and becomes low at a position away from the fastening bolt (position between the fastening bolts). It has been proposed to change the thickness of the stopper of the metal gasket in accordance with the surface pressure distribution, thereby making the surface pressure uniform and ensuring roundness around the cylinder. For example, JP-A-4-
In the metal gasket described in JP-A-307178, the stopper is constituted by a metal ring (shim plate) and a deposit layer of metal particles formed by a thermal spraying method, and by changing the thickness of the deposit layer, The thickness of the stopper is changed according to the surface pressure distribution.

[0010]

However, as described above, as a method of changing the thickness of the stopper in order to make the surface pressure uniform, a method described in the above-mentioned publication (for example, a method of depositing a metal particle deposit layer by a thermal spraying method). Forming a portion having a changed thickness) is the most effective method. However, even if this method is employed, a thermal spraying step is required for a metal ring, so there is room for improvement in terms of reduction in manufacturing costs.

Japanese Utility Model Registration No. 2514490 discloses that the sealing pressure around the cylinder is increased by fixing a support plate (edge plate) at a position surrounding the cylinder in the main body (substrate) of the metal gasket. Although described, the support plate is formed in a shape overlapping the peripheral portion of the cylinder hole of the main body, and the seal width around the cylinder by the support plate is constant.

The present invention provides a metal gasket capable of ensuring uniform roundness around a cylinder by making the surface pressure uniform, the manufacturing cost of which can be reduced compared with the prior art.

[0013]

SUMMARY OF THE INVENTION In order to solve the above-mentioned problems, the present invention provides a bolt hole for mounting, a hole for a cylinder provided in correspondence with a cylinder, and a water hole in the periphery of the cylinder. In a metal gasket in which a metal substrate having a water passage hole and an edge plate for increasing the seal pressure around the cylinder are stacked, the seal width around the cylinder by the edge plate is set to a surface pressure distribution generated at the time of bolt fastening. Accordingly, a portion where the surface pressure is high (for example, near the bolt hole) is narrow, and a portion where the surface pressure is low (for example, between the bolt holes).
Provides a metal gasket characterized by being formed widely.

According to this metal gasket, the sealing pressure around the cylinder by the edge plate is small at the portion where the surface pressure generated at the time of bolt fastening is high, and is large at the portion where the surface pressure is low. Therefore, as compared with the case where the seal width around the cylinder by the edge plate is constant, the surface pressure at the portion where the surface pressure is increased is reduced or alleviated, and the surface pressure at the portion where the surface pressure is reduced is increased. As a result, the surface pressure generated around the cylinder can be made uniform.

The metal gasket of the present invention may be composed of one or two substrates. When one substrate is used, the substrate and the edge plate are stacked by overlapping the edge plate on one surface of the substrate. When there are two substrates, the substrate and the edge plate are laminated by sandwiching the edge plate between the two substrates.

In order to change the seal width around the cylinder by the edge plate in accordance with the surface pressure distribution generated when bolts are fastened, the shape of the edge plate is set, for example, in claim 2 or 3.
As shown.

In the metal gasket according to the second aspect, the edge plate has an inner edge located at an edge of the cylinder hole of the substrate, and an outer edge located at a portion of the peripheral edge of the cylinder where the surface pressure generated at the time of bolt fastening is high. It is located inside the line of the board corresponding to the inner end line of the hole, and in the portion where the surface pressure generated at the time of bolt fastening is low, outside the line and inside the line of the board corresponding to the outer end line of the water hole Is formed so as to be located in a certain range. Further, the edge plate and the substrate are joined at the position in the range. That is, the edge plate is connected to the substrate at the position of the water hole on the periphery of the cylinder. Therefore, this metal gasket can employ a coupling means for forming a protruding portion in a water hole of the engine.

In the metal gasket of the third aspect, the inner edge of the edge plate is formed so as to be located at the edge of the cylinder hole of the substrate. In addition, the outer edge of the edge plate is located along the line of the substrate corresponding to the inner end line of the water hole on the peripheral edge of the cylinder in the portion where the surface pressure generated at the time of bolt fastening is low, The hole is formed so as to be located in a range inside the line of the substrate corresponding to the outer end line of the hole. For the portion where the surface pressure generated at the time of bolt fastening is high, the outer edge of the edge plate is located within the above range, and an opening is provided near the line of the substrate corresponding to the inner end line of the water hole in this portion. Accordingly, the outer end line of the seal width by the edge plate of this portion is formed inside the above line (the line of the substrate corresponding to the inner end line of the water hole). In addition, the edge plate and the substrate are joined at a portion located within the range outside the opening. That is, the edge plate is connected to the substrate at the position of the water hole on the periphery of the cylinder. Therefore, this metal gasket can employ a coupling means for forming a protruding portion in a water hole of the engine.

According to a fourth aspect of the present invention, there is provided the metal gasket according to the second and third aspects, wherein the connecting portion between the edge plate and the substrate is an outer edge portion of the edge plate, and an outer end line is an outer end line of the water hole. It is formed so as to be outside the line of the corresponding substrate, and this outer edge portion has a folded structure slightly folded inside the outer end line of the water hole, and in this case, Since the connection between the edge plate and the substrate is performed at the folded portion, the strength of the connection is increased.

[0020] The metal gasket of claim 5 is characterized in that:
In the metal gasket of No. 4, the inner edge of the edge plate is formed such that the inner edge line of the edge plate is inside the line of the cylinder hole, and this inner edge portion is folded back at the line of the cylinder hole. The folded-back structure has at least one of the thickness and the folded width of the folded inner edge portion according to the surface pressure distribution generated at the time of bolt fastening. It is characterized in that the portion is thin, the portion where the surface pressure is low is thick, and the turnback width is formed such that the portion where the surface pressure is high is narrow and the portion where the surface pressure is low is wide.

According to this metal gasket, the sealing pressure due to the folded portion of the inner edge of the edge plate is reduced near the bolt where the surface pressure increases when the bolt is fastened, and the surface pressure decreases as between the bolts. Since the pressure is increased in the portion, the surface pressure generated around the cylinder can be made more uniform.

The metal gasket according to the sixth aspect is the first aspect.
In the metal gasket of No. 5, a bead is formed at a peripheral portion of the cylinder hole of the substrate, and a portion of an edge plate disposed between an end of the bead opposite to the cylinder hole side and the cylinder hole is formed. A bead having a wavy cross section having a vertex at a circle concentric with the cylinder hole is formed.

According to this metal gasket, the bead provided on the edge plate can effectively prevent the bead of the substrate from being plastically deformed and the sealing property from deteriorating, and the cross section of the edge plate is corrugated. Processing accuracy errors can be absorbed.

[0024]

Embodiments of the present invention will be described below. 1 and 2 are views showing a first embodiment of the metal gasket of the present invention. FIG. 1 is a plan view showing a state where the upper substrate of the metal gasket is removed.
FIG. 2 is a view showing an arrangement of the metal gasket with respect to the engine, and corresponds to a sectional view taken along line AA of FIG.

First, as shown in FIG. 2, the metal gasket 10 is attached to each of the deck surfaces 105, 1 of the cylinder block 103 and the cylinder head 104 of the engine which face each other.
06, a seal is provided between the two deck surfaces 105 and 106. A cylinder 107 is formed in the cylinder block 103. As is well known in the cylinder block 103, power is generated by raising and lowering a piston by exploding a gas mixture of fuel and air.

The cylinder block 103 is made of an aluminum alloy, and a cast iron sleeve 108 forming a peripheral wall of a cylinder 107 is mounted on the cylinder block 103 as a part of the cylinder block 103 to form a so-called aluminum engine. In addition, this cast iron sleeve 10
Numeral 8 denotes a step formed with a step 108a. Here, a step in which the step 108a is supported on the upper surface of the step 103a of the cylinder block 103 is shown. Alternatively, it may be mounted on the cylinder block 103 by casting.

A well-known water jacket 109 is provided around the cylinder 107 of the cylinder block 103.
Are formed, and the cooling water passes therethrough to mainly cool the cylinder block 103. The water jacket 109 is an example of a water hole referred to in the present invention. Cylinder head 10
As shown in FIG. 2, a water hole 111 communicating with the water jacket 109 is also formed on the cylinder head 104 so that the cylinder head 104 is cooled. Water jacket 1 for cylinder block 103
Although 09 is formed in a cylindrical shape on the entire outer periphery of the cylinder 107, the water holes 111 of the cylinder head 104 are not formed on the entire surface facing the water jacket 109, but are formed partially in the circumferential direction of the surface. I have.

Next, the metal gasket 10 is composed of two substrates 1 and one edge plate 2 laminated and sandwiched between these substrates 1, and has an engine having one cylinder. The substrate 1 has one cylinder hole 1
1 is provided. At four corners of the substrate 1, bolt holes 12 for attachment are formed. Note that reference numeral 1 in FIG.
0a is an oil hole.

The cylinder hole 11 and the bolt hole 12 of the substrate 1
A water passage hole 13 is provided at a position overlapping the water hole 111 of the cylinder head 104. That is, the water passage hole 13 corresponds to a line 109a corresponding to an inner end line (a circle concentric with the cylinder 107) of the water jacket 109 of the cylinder block 103 and an outer end line (a circle concentric with the cylinder 107). A plurality of lines (in this case, at four locations near the bolt holes 12) are partially provided along the circumferential direction of these lines between the lines 109b.

The substrate 1 has a cylinder hole 11.
A bead 14 having an arcuate cross-section is formed at a portion of the peripheral edge of the hole closer to the cylinder hole 11 than the water passage hole 13. The vertex line 14a of the bead 14 is shown by a dashed line in FIG.

The edge plate 2 is for increasing the sealing pressure around the cylinder 107.
09b and the hole 11 for cylinders. The edge plate 2 is provided with a cylinder hole 21 having the same size as the cylinder hole 11 of the substrate 1.
By laminating the substrates 1 and 21 together with the substrate 1, the inner edge of the edge plate 2 is positioned at the edge of the cylinder hole 11 of the substrate 1.

The outer edge of the edge plate 2 is formed by alternately arranging an outer portion 22 located outside the line 109a and an inner portion 23 located inside the substrate 109 at four locations along the circle forming the line 109a. Have each. This outer part 22
Is disposed between adjacent water passage holes 13 of the substrate 1, and the inner portion 23 is located between the water passage holes 13 and the cylinder hole 1.
It is arranged at a position on one side. In other words, the outer end line of the edge plate 2 has a shape in which arc-shaped concave portions are provided at four locations which are concentric with the circle forming the line 109b and are separated at equal intervals around a circle having a slightly smaller diameter. This recess corresponds to the inner portion 23 of the outer edge of the edge plate 2.

At the outer portion 22 of the outer edge of the edge plate 2, the edge plate 2 and the substrate 1 are joined by the joining means 3. That is, the edge plate 2 is joined to the substrate 1 at a position between the bolt holes 12 and the water jacket 109 of the cylinder block 103.

As described above, the edge plate 2 has the seal width around the cylinder and the bolt hole 12 where the surface pressure increases when the bolt is fastened.
Are formed narrow between the bolt holes 12 where the surface pressure is reduced when the bolts are fastened. Therefore, according to this metal gasket 10,
The sealing pressure around the cylinder by the edge plate 2 is small in the vicinity of the bolt hole 12 where the surface pressure generated at the time of bolt fastening is high, and is large in the portion between the bolt holes 12 where the surface pressure is low. Become.

Therefore, as compared with the case where the seal width around the cylinder by the edge plate is constant, the surface pressure in the vicinity of the bolt hole 12 is reduced and alleviated, and the portion between the bolt hole 12 and the bolt hole 12 is reduced. Surface pressure increases. As a result, the surface pressure generated around the cylinder can be made uniform. Also,
The surface pressure generated around the cylinder can be made uniform by simply sandwiching the edge plate 2 cut into a predetermined shape between the substrates 1 and joining the same. Can be reduced.

As shown in FIG. 2, in the arrangement of the metal gasket 10 with respect to the engine, the connecting means 3
Is the water jacket 1 of the cylinder block 103
09 is provided below the water hole 111 of the cylinder head 104. Since the deck surfaces 105 and 106 do not exist at this position, the coupling means 3 that forms a protrusion in the water jacket 109 or the water hole 111 can be employed.

FIG. 3 shows an example of such a coupling means 3. The joining means 3 cuts each of the laminated plates (the substrate 1 and the edge plate 2) at two mutually independent main cutting lines 3a, and cuts the laminated plate between the main cutting lines 3a with a step larger than the laminated plate thickness. And projecting in the direction of the water jacket 109 or the water hole 111 to form the protruding portion 3b.
And a pair of inclined portions 33 inclined from the central portion 32 toward the surface of the plate.
Among them, a total of four slope forming lines 34a forming the slope portion 33 are formed such that adjacent ones in the circumferential direction face different directions in the plane of both plates. Note that reference numeral 3
c is a sub cutting line.

The water jacket 10 that makes the size of the protruding portion 3b protrude by employing such a coupling means 3 is adopted.
9 or the size of the opening of the water hole 111, the protrusion 3b hits the periphery of the opening of the water jacket 109 or the water hole 111.
Positioning on the zero deck surface is facilitated. However,
The coupling means 3 is not limited to this, and may be a rivet, an eyelet, or the like.

FIGS. 4 to 6 are views showing a second embodiment of the metal gasket of the present invention. FIG. 4 is a plan view showing the arrangement of the edge plate with respect to the substrate. 5 is a view corresponding to a cross section taken along line BB of FIG. 4 in a state where the lower substrate is removed, and FIG. 6 is a view corresponding to a cross section taken along line CC in FIG. 4 in a state where the lower substrate is removed. FIG.

In the metal gasket 10, the shape of the substrate 1 is the same as that of the first embodiment, and the basic shape of the edge plate 2 is also the same. That is, the outer edge of the edge plate 2 has the outer portion 22 and the inner portion 23 alternately at four locations, and the substrate 1 and the edge plate 2 are joined at the outer portion 22. However, it differs from the first embodiment in that the outer portion (coupling portion) 22 has a folded structure and the inner edge of the edge plate 2 also has a folded structure.

An outer portion 22 forming an outer edge of the edge plate 2
The outer edge portion 2 of the edge plate 2 is indicated by a two-dot chain line in FIG.
2a is formed so that the outer end line is outside the line 109b, and the outer edge portion 22a is
It has a folded structure that is folded back along a line along line 109b, which is slightly inside 9b.

The inner edges 24a, 24a of the edge plate 2
b, as shown by a two-dot chain line in FIG. 4, the inner edge portion 24 of the edge plate 2 is formed so that the inner end line is inside the line of the cylinder hole 21, and the inner edge portion 24 is This is a folded structure that is folded at the line. As shown in FIGS. 5 and 6, the thickness T1 of the folded portion 24a between the bolt holes 12 at which the surface pressure decreases when the bolts are fastened is the bolt hole 12 at which the surface pressure increases when the bolts are fastened. Is thicker than the thickness T2 of the folded portion 24b in the vicinity, and the width W1 of the folded portion 24a is formed wider than the width W2 of the folded portion 24b.

Here, the folded portion 24a and the folded portion 2
As a method of providing a difference in the thickness of 4b, a method of changing the pressure at the time of forming a folded portion by a pressure press and the like can be mentioned. Further, as a method for providing a difference between the folded width of the folded portion 24a and the folded width of the folded portion 24b, there is a method of setting the inner end line of the inner edge portion 24 in consideration of an increase by the press.

Therefore, according to the metal gasket 10, the edge plate 2 and the substrate 1 are joined together at the outer portion 22 having a structure in which the outer edge of the edge plate 2 is folded. In addition to this, there is an effect that the strength of the connection is increased. Further, the sealing pressure due to the folded portion of the inner edge of the edge plate 2 becomes lower at the portion where the surface pressure becomes higher at the time of bolt fastening,
Since the surface pressure increases in the portion where the surface pressure decreases, the surface pressure generated around the cylinder can be made more uniform than in the first embodiment.

FIGS. 7 and 8 are views showing a third embodiment of the metal gasket of the present invention. FIG. 7 is a plan view showing a state where the upper substrate of the metal gasket is removed.
FIG. 8 is a diagram corresponding to a cross section taken along line DD of FIG. 7 in a state where the upper substrate is provided.

The shape of the metal gasket 10 is the same as that of the first embodiment except that the arrangement of the water passage holes 13 is between the bolt holes 12. The inner edge of the edge plate 2 is formed so as to be located at the edge of the cylinder hole 11 of the substrate 1 by providing the same cylinder hole 21 as the cylinder hole 11 of the substrate 1 as in the first embodiment. Have been.

The outer edge of the edge plate 2 is connected to the line 109a.
With reference to a circle concentric with the circles forming these lines arranged in the middle between the reference circle and the line 109b, a convex portion 25 bulging toward the line 109b from the reference circle and a concave portion 26 concave to the line 109a are formed by the reference circle. The shape is provided alternately at equal intervals around the circumference. The recess 26 is provided to prevent the outer edge of the edge plate 2 from overlapping the water passage hole 13 of the substrate 1 and has the same shape as the inner line of the water passage hole 13.

That is, the outer edge of the edge plate 2 is partially formed between the bolt holes 12 of the substrate 1 (the water passage hole 1).
3) is located along the line 109a, and the rest is located between the line 109a and the line 109b.
The portion near 2 is formed so as to be located within the range between the line 109a and the line 109b.

An opening 27 is provided in the vicinity of the line 109a of the projection 25, and the opening 27 of the projection 25 is provided.
The portion on the side of the line 109b is a connecting portion by the connecting means 3. That is, the edge plate 2 is
2 and at the position of the water jacket 109 of the cylinder block 103, it is connected to the substrate 1. Therefore, as in the first embodiment, the coupling means 3 shown in FIG. 3 can be employed.

The opening 27 is connected to the line 109a.
From the side of the line 109b and the side of the cylinder hole 21 are cut out in an arc shape, and the cylinder hole is formed so that the width of the projection 25 on the line 109b side is a width that can be connected by the connecting means 3. On the 21 side, it is cut out outside the bead 14. Thereby, the bolt hole 1
The outer end line of the seal width by the edge plate 2 in the vicinity of 2 is
It is inside the line 109a.

As described above, the edge plate 2 is such that the seal width around the cylinder is narrow near the bolt hole 12 where the surface pressure increases when the bolt is fastened, and the bolt hole 12 and the bolt decrease the surface pressure when the bolt is fastened. It is widely formed in a portion between the hole 12.

As shown in FIG. 8, the edge plate 2
An end (outer peripheral line L of the bead 14) of the bead 14 of the substrate 1 on the opposite side to the cylinder hole 11 side and the cylinder hole 21
A bead 28 having a corrugated cross section is formed between them. All the apex positions 28a of the bead 28 forming the wave irregularities
Is a circle concentric with the cylinder hole 11.

Therefore, according to the metal gasket 10, the sealing pressure around the cylinder by the edge plate 2 becomes small at the portion where the surface pressure generated at the time of bolt fastening is high, and is large at the portion where the surface pressure is low. The surface pressure generated around the cylinder can be made uniform. Further, the surface pressure generated around the cylinder can be made uniform only by sandwiching the edge plate 2 cut into a predetermined shape between the substrates 1 and joining the same, thereby reducing the manufacturing cost and the conventional surface pressure. It can be reduced from technology. Further, the bead 28 provided on the edge plate 2 can effectively prevent the sealing property from being deteriorated due to the plastic deformation of the bead 14 of the substrate 1. Further, since the cross section of the bead 28 is corrugated, there is an effect that errors in the processing accuracy of the edge plate 2 are absorbed.

The metal gasket 1 of each of the above embodiments
0 is for an engine having one cylinder, so the substrate 1 is provided with one cylinder hole 11. However, the present invention is not limited to this, and a metal gasket for an engine having a plurality of cylinders is provided. Also applies. In that case,
Since the surface pressure at the portion between the adjacent cylinder holes becomes particularly small, the seal width by the edge plate at this portion is particularly widened so that the surface pressure distribution becomes uniform.

In each of the above embodiments, a metal gasket having two substrates has been described. However, the present invention is not limited to this, and includes a metal gasket having only one substrate. Then, even when only one substrate is provided, the structure of the edge plate of each of the above embodiments can be adopted as it is.

[0056]

As described above, according to the metal gasket of the present invention, the seal width around the cylinder by the edge plate is changed around the cylinder by a simple structure in which the seal width is changed according to the surface pressure distribution generated when bolts are fastened. Since the generated surface pressure can be made uniform, the manufacturing cost can be reduced compared to the conventional technology for making the surface pressure uniform.

In particular, according to the metal gasket of the fourth aspect, in addition to the above effects, the effect of increasing the bonding strength between the edge plate and the substrate can be obtained. In particular, according to the metal gasket of the fifth aspect, the effect of making the above-mentioned surface pressure generated around the cylinder uniform becomes particularly high.

In particular, according to the metal gasket of claim 6, in addition to the above effects, it is possible to effectively prevent the bead of the substrate from being plastically deformed and the sealing property from deteriorating.
There is also an effect that errors in processing accuracy of the edge plate can be absorbed.

[Brief description of the drawings]

FIG. 1 is a diagram showing a first embodiment of a metal gasket of the present invention, and is a plan view showing a state where an upper substrate is removed.

FIG. 2 is a view showing an arrangement of a metal gasket of the first embodiment with respect to an engine, and corresponds to a cross-sectional view taken along line AA of FIG. 1;

FIG. 3 is a perspective view illustrating an example of a coupling unit.

FIG. 4 is a view showing a second embodiment of the metal gasket of the present invention, and is a plan view showing an arrangement of an edge plate with respect to a substrate.

5 is a view showing the metal gasket of the second embodiment, and is a view corresponding to a cross section taken along line BB of FIG. 4 with a lower substrate removed.

FIG. 6 is a view showing a metal gasket according to the second embodiment, and is a view corresponding to a cross section taken along line CC of FIG. 4 with a lower substrate removed.

FIG. 7 is a view showing a third embodiment of the metal gasket of the present invention, and is a plan view showing a state where an upper substrate is removed.

FIG. 8 is a view showing a metal gasket according to a third embodiment, and is a view corresponding to a cross section taken along line DD of FIG. 7 in a state where an upper substrate is provided.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Substrate 2 Edge plate 3 Coupling means 3a Main cutting line 3b Projecting part 3c Subcutting part 10 Metal gasket 11 Substrate cylinder hole 12 Bolt hole 13 Water passage hole 14 Board bead 14a Board bead vertex line 21 Edge plate Cylinder hole 22 Outer portion of outer edge of edge plate 22a Outer edge portion of edge plate 23 Inner portion of outer edge of edge plate 24 Inner edge portion of edge plate 24a Inner edge of edge plate (returned portion) 24b Inner edge (returned portion) 27 Opening 28 Bead of edge plate 28a Vertex position of bead of edge plate 32 Center portion of coupling means 33 Slope portion of coupling means 34a Slope forming line of coupling means 103 Cylinder block 104 Cylinder head 105 Cylinder Deck surface of block 106 Deck surface of cylinder head 109 Water jacket (water hole around cylinder) Inner end line 109b thickness of thickness T2 folded portion of the width T1 folded portion of the width W2 folded portion of the water hole W1 folded part of the outer end line 111 cylinder head of the cylinder periphery of the water hole of 09a cylinder periphery of the water hole

Claims (6)

[Claims] 1. A metal substrate having a mounting bolt hole, a cylinder hole provided corresponding to a cylinder, and a water passage hole provided corresponding to a water hole on a peripheral edge of the cylinder, and a sealing pressure around the cylinder. In the metal gasket in which the edge plate is stacked, the seal width around the cylinder by the edge plate is reduced according to the surface pressure distribution generated at the time of bolt fastening. A metal gasket characterized by being formed widely. 2. An inner edge of the edge plate is located at an edge of a cylinder hole of the substrate, and an outer edge of the edge plate is located at an inner end line of a water hole at a peripheral edge of the cylinder in a portion where a high surface pressure is generated at the time of bolt fastening. It is located inside the line of the corresponding board, and in the portion where the surface pressure generated at the time of bolt fastening is low, it is located outside the line and inside the line of the board corresponding to the outer end line of the water hole. 2. The metal gasket according to claim 1, wherein the edge plate and the substrate are connected at the position in the range. 3. The inner edge of the edge plate is located at the edge of the cylinder hole of the substrate, and the outer edge is located at the inner end line of the water hole at the peripheral edge of the cylinder in the portion where the surface pressure generated at the time of bolt fastening is low. Along the line of the corresponding board, or located outside the line and inside the line of the board corresponding to the outer end line of the water hole, the area where the surface pressure generated at the time of bolt fastening is high is the range. By providing an opening near the line of the substrate corresponding to the inner end line of the water hole of the portion, the outer end line of the seal width by the edge plate of the portion is inside the line 2. The metal gasket according to claim 1, wherein the edge plate and the substrate are joined at a portion located within the range outside the opening. 4. The connecting portion of the edge plate with the substrate is formed such that the outer edge portion of the edge plate is outside the line of the substrate corresponding to the outer edge line of the water hole. The metal gasket according to claim 2 or 3, wherein the portion has a folded structure slightly folded inside the outer end line of the water hole. 5. The inner edge of the edge plate is an inner edge portion of the edge plate,
The inner end line is formed so as to be inside the line of the cylinder hole, and the inner edge portion has a folded structure folded back by the line of the cylinder hole, and the thickness and the folded width of the folded inner edge portion are formed. According to the distribution of surface pressure generated at the time of bolt fastening, at least one of the thickness is thinner at the portion where the surface pressure is higher, the portion at the lower surface pressure is thicker, and The metal gasket according to any one of claims 1 to 4, wherein a portion where the surface pressure is high is narrow and a portion where the surface pressure is low is wide. 6. A bead is formed at a peripheral portion of a cylinder hole of a substrate, and a portion of an edge plate disposed between an end of the bead opposite to the cylinder hole side and the cylinder hole includes: The metal gasket according to any one of claims 1 to 5, wherein a bead having a corrugated cross section is formed with a vertex at a circle concentric with the cylinder hole.