JP3075984B2 - 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 interposed between joint surfaces of a cylinder head and a cylinder block of an internal combustion engine to seal the joint.

[0002]

2. Description of the Related Art As a conventional metal gasket of this type, for example, as shown in FIG. 8, double grommets b and c are fixed to the periphery of a combustion chamber hole a formed corresponding to the end of a cylinder bore. In addition, a wire ring e having a larger wire diameter than the substrate d is inserted into the double grommet b or c, or a shim plate f is attached to the periphery of the combustion chamber hole a as shown in FIG.
Are fixed by welding.

[0003] In any of these metal gaskets, the lamination thickness of the peripheral portion of the combustion chamber hole a is made larger than other portions to provide a plate thickness difference, and the cylinder head g and the cylinder block h (see FIG. 10, refer to FIG. 11) so that the surface pressure is most concentrated on the peripheral edge when tightening with the fastening bolt by interposing between the joining surfaces with the joint surface with the joint surface, thereby applying the maximum load to the peripheral edge of the cylinder bore end to seal. Combustion chamber hole a at the periphery
The bead i provided around the side away from the side is protected and the intrusion of the combustion gas is prevented.

[0004]

By the way, the tendency of recent engines is to make the cylinder head g and the cylinder block h all aluminized due to the demand for weight reduction and the wet liner system in which the cylinder liner is directly cooled with water. However, in the wet liner method, as shown in FIGS. 12 and 13, the deck surfaces of the cylinder sleeves j adjacent to each other may be irregular due to the processing accuracy, and a step t ₀ may occur. Many. In particular, the cylinder sleeve j having the shape shown in FIG. 13, step t ₀ is likely to occur.

However, in the above-described conventional metal gasket, the lamination thickness of the peripheral portion of the combustion chamber hole a is made thicker than other portions without providing a space portion in the thickness direction, so that the peripheral portion has a maximum thickness. Since a load is applied, a step t is formed on each deck surface of the cylinder sleeve j adjacent to each other.
_{When 0} occurs, there is a disadvantage that the step t ₀ cannot be absorbed when tightening with the fastening bolt, and a sufficient sealing effect cannot be obtained.

In addition, the use of aluminum for the engine has spurred the reduction of the rigidity of the engine, and the influence of heat has been increasing. In the case, the cast iron sleeve sinks or the flanged sleeve has no aluminum support, so the cylinder bore deforms greatly,
Problems such as power loss of the engine, increase in oil consumption, blow-through of explosive gas, etc. occur, which causes the engine durability to decrease.

More specifically, as shown in FIGS. 10 and 11, a cast iron cylinder sleeve m having a thickness of about 2 to 5 mm is formed on an inner peripheral portion of a cylinder bore k of an aluminum cylinder block of an aluminum engine. The metal gasket is provided while being held in the cylinder block body n. In each of the above-described metal gaskets, the end portion of the cylinder bore k is located at a position shifted from the holding surface o of the cylinder block body n to the cylinder bore k side. The maximum load is applied, and the maximum load becomes 1.5 to 2 times that of the cold state due to the cold cycle of the engine or the volume expansion due to the heat during the operation, and the pulsation due to the explosion is added. Since the area of the surface o is small, the cylinder bore k is greatly deformed.

SUMMARY OF THE INVENTION The present invention has been made to solve such a problem, and has been made in view of the above circumstances.
The seal effect can be improved by absorbing the steps on the deck surfaces adjacent to each other on the leave ,
Prevents cylinder bore deformation and improves engine durability
It is an object of the present invention to provide a metal gasket capable of achieving the following.

[0009]

[0010]

In order to achieve the above object, a metal gasket according to claim 1 is provided with a portion having the largest number of metal substrates in a thickness direction around a combustion chamber hole and a cylinder block. An internal combustion engine in which a maximum load is applied to a portion having the largest number of substrates when a fastening bolt is inserted and interposed between the joint surfaces of the substrate and the cylinder head, thereby sealing between the joint surfaces. In the metal gasket for use, the substrate is provided with a first space portion.
Bend the substrate in the thickness direction to the periphery of the combustion chamber hole
Two sheets are arranged, and the end of the bent portion is set in the second empty space.
The combustion chamber at the peripheral portion is bent inward with a space therebetween.
Three substrates are arranged in the thickness direction around the side away from the hole.
A metal gasket, wherein the metal gasket is placed on a portion having the largest number of substrates .

[0011] Metal gasket according to claim 2, wherein the circumferential
The fastening bolt having heat resistance in a first space portion of the edge portion.
Deformable member that can be deformed in the thickness direction by the load when tightened with
It is characterized by having been charged .

[0012] The metal gasket according to the third aspect is the metal gasket .
A soft wire rod capable of being deformed in the thickness direction by a load when tightened by the fastening bolt is inserted into the space portion (2) .

[0013] A metal gasket according to a fourth aspect is characterized in that the deformable member is an elastic material. The metal gasket according to claim 5 is characterized in that a bead made of a rubber-based material having a thickness higher than the total thickness of the portion is provided outside the portion having the largest number of substrates.

According to a sixth aspect of the present invention, in the metal gasket, the edge of the substrate disposed outside the bolt hole of the fastening bolt is bent so that the two substrates are arranged in the thickness direction. A shim for adjusting the total thickness is sandwiched between the plurality of substrates.

According to a seventh aspect of the present invention, there is provided a metal gasket, wherein a sub-plate is provided outside a portion where the number of substrates is the largest, and at least one of the substrate and the sub-plate surrounds a hole formed in the substrate. An uneven full bead or a stepped half bead is formed.

The metal gasket according to claim 8 is characterized in that a heat-resistant sealant is applied.

[0017]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is an explanatory cross-sectional view for explaining a metal gasket as an example of an embodiment of the present invention, and FIG. 2 is a cross-sectional view showing a state where the metal gasket is interposed between joint surfaces of a cylinder block and a cylinder head. FIG. 3 and FIG. 3 are cross-sectional views showing an interposed state between adjacent cylinder sleeves.

In FIG. 1, reference numeral 1 denotes a metal gasket. The metal gasket 1 is formed by bending a single substrate 1a made of an elastic metal plate such as a stainless steel plate. Cylinder bore 2 of substrate 1a
Space in a portion corresponding to the end portion is formed with a combustion chamber hole 3, the peripheral edge portion 4 of the combustion chamber holes 3 in the radial direction outer side of the combustion chamber holes 3 (see FIG. 2) (the first space Part) and two sheets are arranged in the thickness direction by being bent upwards with 5 present. A deformable member 9 such as expanded graphite, which has heat resistance and is elastically deformable in the thickness direction, is inserted in the space 5 of the peripheral portion 4.

As shown in FIG. 1, the distal end 4a of the bent portion of the peripheral portion 4 is bent downward toward the radially inner side of the combustion chamber hole 3 with a space (second space ) 6a. Have been. As a result, the three substrates 1a are arranged in the thickness direction around the periphery of the peripheral portion 4 on the side separated from the combustion chamber hole 3, and the portion 6 having the largest number of the substrates 1a is formed. A flat portion 7 is formed by disposing one substrate 1a having a smaller number than the peripheral portion 4 in the thickness direction at a portion on the side away from the combustion chamber hole 3. It is preferable that the width A of the portion 6 having the largest number of substrates 1a be equal to or less than half the width B of the peripheral portion.

The flat portion 7 around the portion 6 having the largest number of substrates 1a is provided with a seal other than around the combustion chamber hole 3 (excluding the peripheral portion 4 and the portion 6 having the largest number of substrates 1a). A bead 7a made of a rubber-based material is provided on both surfaces so as to be higher than the total thickness of the portion 6, and around the bead 7a, bolt holes for fastening bolts (not shown) are formed in the circumferential direction. A plurality are formed at predetermined intervals. Here, before fastening by the fastening bolt, FIG.
As shown, the initial thickness t ₁ of the peripheral portion 4 including a deformable member 9 is thicker than the thickness t ₂ of the largest portion 6 of the number of substrates 1a, and the initial thickness t ₁ is 2 As shown in
It is set so as to follow the deformed thickness t ₃ of the portion 6 having the largest number of substrates 1a after fastening (after deformation) by the fastening bolt.

Although not shown, one or both sides of the substrate 1a are made of a heat-resistant rubber coating or molybdenum disulfide mixed with resin in order to absorb the surface roughness of the sealing surface on the engine side. Is subjected to a surface microseal treatment by baking. Seals other than the periphery of the combustion chamber hole 3, that is, seals around water holes and oil holes (not shown) in addition to the bolt holes, use a method such as a rubber print, a rubber mold, or a single stroke using a dispenser. As shown in FIGS. 1 and 2, the outer edge 1b of the substrate 1a outside the bolt holes and the ends such as oil holes are used to balance the load with the periphery of the combustion chamber hole 3 when the bolts are fastened. And two substrates 1a are arranged in the thickness direction by bending upward, and a shim 10 for adjusting the total thickness is sandwiched between the two substrates 1a arranged in the thickness direction.

FIG. 3 shows cylinder sleeves 1 adjacent to each other.
Step t ₀ (the step t ₀ is between 3 usually at most 0.
It is about 1 mm. FIG. 2 is a cross-sectional view showing a state after the metal gasket 1 is interposed between the joint surface of the cylinder head 11 and the joint surface of the cylinder block 12 of the aluminum engine in which the occurrence of () occurs, and the metal gasket 1 is tightened with fastening bolts. The cylinder block 12 includes a cylinder sleeve 13 made of cast iron having a thickness of about 2 to 5 mm provided on an inner peripheral portion of the cylinder bore 2.
Flange 1 formed on the outer periphery of the upper end of sleeve 13
And an aluminum cylinder block main body 15 having a stepped holding surface 14 for holding 3a.

When fastening with the fastening bolt, the peripheral edge 4 of the metal gasket 1 is arranged on the upper surface of the end of the sleeve 13 corresponding to the peripheral edge of the end of the cylinder bore 2, and the portion 6 having the largest number of substrates 1a is removed. The cylinder 13 is disposed on the upper surface of the flange portion 13a of the sleeve 13 on the side radially outwardly separated from the peripheral edge of the end of the cylinder bore 2, and the tightening is performed in this state.

The cylinder sleeve 13 on the higher side (right side in FIG. 3) of the cylinder sleeves 13 adjacent to each other
In the portion arranged on the deck surface, the peripheral portion 4 is first compressed and deformed, and the space 6a of the portion 6 having the largest number of substrates 1a is compressed and deformed together with the peripheral portion 4 while being gradually crushed from the middle. Finally, the three substrates 1a arranged in the thickness direction of the portion 6 are brought into close contact with each other and stopped. At this time, the surface pressure is concentrated most on the portion 6 having the largest number of substrates 1a, and the maximum load is applied on the side radially outwardly separated from the peripheral edge of the end of the cylinder bore 2, and the load is applied below the flange portion 13a. Is received by the holding surface 14 of the cylinder block body 15 located at the position. As a result, deformation of the cylinder bore 2 is prevented, and
In this case, a sufficient surface pressure is applied by the elastic deformation of the deformable member 9 in the thickness direction, the primary seal is performed at the peripheral portion 4, and the secondary seal is performed at the portion 6 having the largest number of substrates 1a. A good sealing effect can be obtained due to the sealing structure.

On the other hand, at the lower portion (left side in FIG. 3) of the portion arranged on the deck surface of the cylinder sleeve 13, the peripheral portion 4 is first compressed and deformed similarly to the above-described high side,
The space 6a of the portion 6 where the number of substrates 1a is the largest from the middle
Is gradually compressed and deformed together with the peripheral portion 4, but this deformation is limited by the step of the cylinder sleeve 13 on the high side, and the three substrates 1a arranged in the thickness direction of the portion 6 are mutually deformed. It stops in a state where the space portion 6a is left without being in close contact with the entire surface.

However, since the bending R of the portion 6 having the largest number of substrates 1a disposed on the deck surface of the lower cylinder sleeve 13 is smaller, the joining area is smaller than that of the higher cylinder sleeve 13 but smaller. A surface pressure substantially equal to that of the cylinder sleeve 13 on the high side is generated in the R portion, and three substrates 1a arranged in the thickness direction are in close contact with each other on the cylinder sleeve 13 on the high side. As a result, no more fluctuating load is applied to the space 6a which functions as a stopper and remains on the lower side.

Therefore, the surface pressures are concentrated on the portions 6 having the largest number of substrates 1a disposed on the respective deck surfaces of the cylinder sleeves 13 adjacent to each other, and are separated radially outward from the peripheral edge of the end of the cylinder bore 2. A substantially equal maximum load is applied to the side of the flange 13a.
Holding surface 14 of cylinder block body 15 located below
Received by As a result, deformation of the cylinder bore is prevented, and a sufficient surface pressure is applied to the peripheral portion 4 by elastic deformation in the thickness direction of the deformation member 9,
A primary sealing is performed at the peripheral edge portion 4 and a secondary sealing is performed at the portion 6 having the largest number of substrates 1a, so that a good sealing effect can be obtained. As a result, it is possible to completely seal an engine having a step in adjacent cylinder sleeves, which was impossible with an existing metal gasket, and to reduce engine power loss, increase oil consumption, and explode due to deformation of a cylinder bore. Problems such as gas blow-through can be eliminated, and the durability of the engine can be improved.

Further, three substrates 1a are arranged in the thickness direction around the peripheral edge 4 of the combustion chamber hole 3, and the bolt hole 8 and the outer edge are disposed on one flat portion 7. In the fastening state by the bolts, it is conceivable that the deflection of the cylinder head 11 becomes too large and an excessive load is applied around the combustion chamber hole 3. In this embodiment, as shown in FIG. The outer edge 1b and the end of the oil hole are bent upward to arrange two substrates 1a in the thickness direction.
Since the load is balanced with the periphery of the combustion chamber hole 3 by holding the shim 10 for adjusting the total thickness between the two substrates 1a, an excessive load is applied around the combustion chamber hole 3. Can be overkill.

In the above-described embodiment, expanded graphite is taken as an example of the deformable member 9. However, the deformable member 9 is not necessarily limited to this, as long as it has heat resistance and is deformable. For example, a mica layer, a fluorine resin, a silicon resin, a mild steel wire, or a metal plate 17 having elasticity as shown in FIG. 6 may be used. Further, the member may not necessarily be an elastically deformable member, and may be a member that can be plastically deformed.

Further, in the above-described embodiment, a seal other than around the combustion chamber hole 3 is made by using a bead 7a made of a rubber-based material, but instead of this, as shown in FIG. An uneven full bead surrounding a water hole, an oil hole, a bolt hole, and the like is provided between the substrate 1a and the sub plate 1c with a single sub plate 1c provided on the upper surface of a portion of the substrate 1a except for the periphery of the combustion chamber hole 3. 20 or a step-shaped half bead 21 may be provided. Further, as shown in FIG. 5, a total of two sub-plates 1c are provided on the upper and lower surfaces of the substrate 1a except for the periphery of the combustion chamber hole 3.
The sub-plate 1c may be provided with an uneven full bead 20 or a stepped half bead 21 surrounding water holes, oil holes, bolt holes and the like. The thickness of the sub-plate 1c is smaller than that of the substrate 1a.

FIG. 7 shows another embodiment of the present invention, which is different from the above-described embodiment in that the space 6a of the portion 6 where the number of substrates 1a is the largest is tightened by fastening bolts. The point is that a soft wire 30 having a circular cross section that can be deformed in the thickness direction by a load is inserted.

Examples of the soft wire 30 include a copper wire, a lead wire, a zinc wire, a mild steel wire and a resin wire. In a diesel engine that requires high explosion pressure and high tightening pressure, the lower cylinder sleeve 1 after bolting is used.
If the space portion 6a remains in the portion 6 where the number of substrates 1a disposed on the deck surface of the third plate 3 is the largest, if the peripheral portion 4 as the primary seal cannot be completely sealed, the second The space 6a may be deformed by the pressure of the explosive gas or the like because the portion 6 as the next seal has a narrow width for generating a high surface pressure.

However, by inserting the soft wire 30 into the space 6a as in this embodiment, a high surface pressure is applied to the vicinity of the bolt on the circumference and a large amount of deformation is caused. The space between the bores is slightly deformed, and the circular cross section of the wire 30 deforms in proportion to the pressing force when deformed by pressing, so that the deformation of the space 6a due to the pressure is prevented and the surface pressure on the wire 30 is reduced. The sealing effect can be averaged by circumferential averaging (indicating the surface pressure per unit area).

[0034]

[0035]

[Effect of the Invention] As apparent from the above description, the present invention
According to the present invention, it is possible to completely seal an engine having a step in adjacent cylinder sleeves, which is impossible with an existing metal gasket, and it is possible to prevent deformation of a cylinder bore and to reduce power loss of an engine as in a conventional engine. This eliminates problems such as an increase in oil consumption and blow-through of explosive gas, and provides an effect of improving engine durability.

In addition, a high explosion pressure and a high tightening pressure are required by inserting a soft wire that can be deformed in the thickness direction by a load when tightened with a fastening bolt into a space portion where the number of substrates is the largest. In diesel engines,
The effect is obtained that the deformation of the space due to the explosion pressure or the like is prevented and the sealing effect on the circumference can be averaged.

Further, the outer edges of the substrate and the ends such as oil holes are bent upward to arrange two substrates in the thickness direction, and a shim for adjusting the total thickness is sandwiched between the two substrates. By balancing the load with the periphery of the combustion chamber hole, the effect of preventing an excessive load from being applied to the periphery of the combustion chamber hole can be obtained.

[Brief description of the drawings]

FIG. 1 is an explanatory cross-sectional view illustrating a metal gasket according to an embodiment of the present invention.

FIG. 2 is a cross-sectional view showing a state where the metal gasket is interposed between joining surfaces of a cylinder block and a cylinder head.

FIG. 3 is a sectional view showing an interposed state between adjacent cylinder sleeves.

FIG. 4 is an explanatory cross-sectional view illustrating a modified example of a bead.

FIG. 5 is an explanatory sectional view for explaining a modified example of a bead.

FIG. 6 is an explanatory cross-sectional view for explaining a modified example of the deformable member.

FIG. 7 is an explanatory cross-sectional view for explaining a metal gasket according to another embodiment of the present invention.

FIG. 8 is an explanatory sectional view for explaining a conventional metal gasket.

FIG. 9 is an explanatory cross-sectional view for explaining another conventional metal gasket.

10 is a cross-sectional view showing a state in which the metal gasket shown in FIG. 8 is interposed between joining surfaces of a cylinder block and a cylinder head.

FIG. 11 is a cross-sectional view showing a state where the metal gasket shown in FIG. 9 is interposed between joining surfaces of a cylinder block and a cylinder head.

12 is a cross-sectional view showing an interposed state between adjacent cylinder sleeves of the metal gasket shown in FIG. 8;

FIG. 13 is a cross-sectional view showing an interposed state between adjacent cylinder sleeves of the metal gasket shown in FIG. 9;

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 ... Metal gasket 1a ... Substrate 1c ... Sub-plate 3 ... Combustion chamber hole 4 ... Peripheral part 5 ... Peripheral part space 6 ... Part with the largest number of substrates 6a ... Part with the largest number of substrates no space part 7a ... Bead made of rubber-based material 9 ... Deformable member 10 ... Shim 11 ... Cylinder head 12 ... Cylinder block 20 ... Full bead 21 ... Half bead 30 ... Wire rod

Claims (8)

(57) [Claims] 1. A part having the largest number of metal substrates in the thickness direction is provided around a combustion chamber hole, and the metal substrate is interposed between joint surfaces of a cylinder block and a cylinder head and is tightened with a fastening bolt when tightened by a fastening bolt. A metal gasket for an internal combustion engine in which a maximum load is applied to a portion having the largest number of sheets, thereby sealing between the joining surfaces, wherein the substrate is bent with a first space portion. The combustion chamber
Along with arranging two substrates in the thickness direction at the periphery of the hole,
Fold the tip of the bent part inward with the second space part
Around the side of the peripheral portion that is separated from the combustion chamber hole.
Surrounding the three substrates in the thickness direction.
Metal gasket characterized by having the largest number of parts . 2. A heat-resistant material is provided in the first space of the peripheral portion.
In the thickness direction with the load when tightened with the fastening bolt
2. The metal gasket according to claim 1, wherein a deformable member is inserted in the metal gasket. 3. A process according to claim 1 or 2 metal gasket according to, characterized in that charged with deformable soft wire in the thickness direction of load when tightened by the fastening bolt to the second space. 4. The metal gasket according to claim 2, wherein the deformable member is an elastic material. 5. The method according to claim 1, wherein a bead made of a rubber-based material having a thickness higher than the total thickness of the portion is provided outside a portion having the largest number of substrates. Metal gasket. 6. An edge portion of the substrate disposed outside the bolt hole of the fastening bolt is bent to dispose two substrates in the thickness direction, and to dispose the two substrates in the thickness direction. The metal gasket according to any one of claims 1 to 5, wherein a shim for adjusting a total thickness is sandwiched between the metal gaskets. 7. An irregular full bead or a stepped shape surrounding a hole formed in a substrate provided on a sub-plate outside a portion where the number of substrates is largest, and provided on at least one of the substrate and the sub-plate. The metal gasket according to any one of claims 1 to 6, wherein a half bead is formed. 8. The metal gasket according to claim 1, wherein a sealant having heat resistance is applied.