JP2000227047A - Metallic gasket - Google Patents

Abstract

PROBLEM TO BE SOLVED: To restrain and prevent deformation of a cylinder head or a cylinder bore by preventing the circumferential edge part only close to the cylinder bore from being in the condition of extremely high bearing pressure and stabilizing the bearing pressure on the circumferential edge of the cylinder bore. SOLUTION: A shim plate 6 is applied to the circumferential edge part of the bore hole 4 of a subplate 3 sandwiched with base plates, it is folded back on the opposite side through the bore hole 4, and the folded back part is pressed to be fixedly fitted to the subplate 3. The plate thickness is formed thin in order of the close part to the bore hole, bead, and the outside, the bearing pressure can be restrained to become extremely high only on the circumferential edge close to the cylinder bore. Further, the total plate thickness of the folded back shim plate 6 and the subplate 3 is changed on the circumferential edge of the bore hole 4, for example, by making the plate thickness thin on the parts of bolt holes 7, the bearing pressure on the circumferential edge of the cylinder bore can be uniformalized at assembling.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an engine which is provided on a joint surface between a block member (cylinder block) and a head member (cylinder head) of an engine to prevent leakage of combustion gas, cooling water and lubricating oil. It relates to a metal gasket to be prevented.

[0002]

2. Description of the Related Art The most important function of a gasket used for an engine is to prevent combustion gas from leaking from a cylinder bore. When this gasket is made of metal, a bead is formed around the bore of the metal gasket. When the cylinder block and the cylinder head are connected by bolts, the beads are elastically deformed so that the beads are crushed, the surface pressure is increased, and the sealing performance is improved. Even if a bead is formed, a single metal plate cannot provide a sufficient sealing function over the entire joint surface, so that a plurality of metal plates are usually stacked to form a metal gasket.

As such a laminated metal gasket, for example, Japanese Patent Publication No. 8-33178 (hereinafter, also referred to as a first conventional example) and Japanese Patent Publication No. 2560046 (hereinafter, referred to as a first conventional example).
Japanese Laid-Open Patent Publication No. 10-220852 (hereinafter also referred to as a third conventional example). Among them, in the first conventional example, a metal plate called an intermediate structure having a similar shape is sandwiched between substrates made of two elastic metal plates. The plates are stacked to form an intermediate structure, and the perimeter of the bore hole of one metal plate is folded back to the opposite side of the other metal plate, and the thickness of the intermediate structure at the perimeter of the bore hole inside the bead portion is increased. By doing so, the surface pressure in the immediate vicinity of the cylinder bore is increased to improve the sealing performance. Further, in the second conventional example, similarly, a metal plate called an intermediate plate having the same shape as the substrate is sandwiched between two elastic metal plates, and is sandwiched. Of the superposed metal plates, the periphery of the bore hole is opened to form a space, and a solid metal pool called a stopper is formed in this space by metal spraying, and the entire periphery of the bore hole inside the bead portion is formed. By increasing the thickness of the intermediate plate, the surface pressure in the immediate vicinity of the cylinder bore is increased to improve the sealing performance. Further, in the third conventional example, a narrow metal plate called a compensating plate corresponding to only the peripheral portion of the bore hole is sandwiched between substrates made of two elastic metal plates, and the peripheral portion of the bore hole is formed. By directly folding and superimposing, and by increasing the thickness of the compensating plate at the periphery of the bore hole inside the bead portion, the surface pressure in the immediate vicinity of the cylinder bore is increased to improve the sealing performance. The compensating plate is sandwiched so as to be pressed between beads of the substrate.

[0004]

However, in the first and second prior arts, only the thickness of the intermediate structure and the intermediate plate at the peripheral portion of the bore hole is large, and the other portions are uniform. Only the surface pressure is extremely large. Generally, the bolts connecting the cylinder block and the cylinder head are connected at, for example, four diametrical directions perpendicular to the cylinder bore, so that the surface pressure between the metal gasket, the cylinder block, and the cylinder head at the periphery of the cylinder bore is compared. Then, the surface pressure in the portion near the bolt is maximum, and the surface pressure in the portion between the bolts is smaller than that. In other words, when only the surface pressure near the cylinder bore is extremely large, the cylinder block and the cylinder head are connected by bolts, and the metal gasket is sandwiched between them.If the cylinder head made of aluminum bends, the periphery of the cylinder bore becomes extremely sharp. The surface pressure is increased, and the surface pressure difference is large between the bolts and between the bolts and between the bore holes. In particular, near the high bolts, the sleeve is inclined inward, and the bore is deformed and does not become a perfect circle. On the other hand, in the third conventional example, since the width of the compensating plate is narrow, the surface pressure between the metal gasket, the cylinder block, and the cylinder head at the peripheral edge of the cylinder bore greatly differs between the bolt portion and the portion between them. Absent. However, in the third conventional example, since the compensating plate having a small width is sandwiched so as to be pressed between the beads of the substrate, it is difficult to position both compensating plates and the assembling workability is poor.

The present invention has been developed in view of these problems, and by stabilizing the surface pressure of the peripheral portion of the cylinder bore, it is possible to secure the perfect circle of the cylinder bore and improve the deformation of the cylinder head while improving the sealing performance. It is an object of the present invention to provide a metal gasket that can prevent the occurrence of a gasket and that is excellent in assemblability.

[0006]

In order to solve the above-mentioned problems, a metal gasket according to a first aspect of the present invention is a metal gasket interposed between a block member and a head member joined by bolts. A sub-plate is laminated between substrates made of a plurality of elastic metal plates having beads formed around a bore hole, and a shim plate having a bead hole peripheral portion turned back is attached to the sub-plate. The sum of the thickness of the substrate, the thickness of the sub-plate, and the thickness of the shim plate is smaller in the order of the periphery of the bore hole, the bead portion, and the outside of the bead portion.

According to a second aspect of the present invention, there is provided a metal gasket according to the first aspect, wherein the shim plate is a metal plate applied to one surface of the sub-plate. It is characterized by being folded back to the other surface and covering the peripheral edge of the bore hole. In the metal gasket according to claim 3 of the present invention, in the invention of claim 2, by pressing the folded portion of the shim plate against the sub-plate and changing the surface pressure at the periphery of the bore hole,
The thickness of the folded back shim plate and the sub plate varies at the periphery of the bore hole.

According to a fourth aspect of the present invention, in the metal gasket according to the third aspect of the present invention, the surface pressure at the time of pressing is changed by changing the width of the folded portion of the shim plate. It is characterized by being changed. According to a fifth aspect of the present invention, in the metal gasket according to the first aspect of the present invention, the shim plate is formed such that a peripheral portion of the bore hole is independently folded, and an unfolded portion is fixed to the sub-plate. It is characterized by having been done.

According to a sixth aspect of the present invention, in the metal gasket according to the fifth aspect, the width of the folded portion of the shim plate changes at the periphery of the bore hole. is there. The metal gasket according to claim 7 of the present invention is the metal gasket according to claim 2 or 5 or 6, wherein the thickness of the sub-plate corresponding to the folded portion of the shim plate is changed at the periphery of the bore hole. The thickness of the folded-up shim plate and the sub-plate is changed at the periphery of the bore hole.

The metal gasket according to claim 8 of the present invention is the metal gasket according to claims 2 to 7, wherein the thickness of the folded portion of the shim plate and the thickness of the plate at the mounting portion between the shim plate and the sub-plate are increased. The sub-plate and the shim plate are formed so that at least one of the plate thickness changes is equal on both sides of the sub-plate.

[0011]

1 and 2 show an embodiment of a metal gasket according to the present invention. In this embodiment, a metal gasket is formed by sandwiching a metal sub-plate 3 having a lower material hardness than a substrate metal plate between two elastic metal substrates. Each of the substrates 1 and 2 and the sub-plate 3 are formed with two or more bore holes 4 penetrating when they are laminated to form a metal gasket. These bore holes 4
When a metal gasket is interposed between a cylinder block and a cylinder head to construct an engine, the metal gasket is provided at a position communicating with a cylinder bore of the engine. Similarly, a bolt hole 7 through which a bolt connecting the cylinder block and the cylinder head passes is also formed.
Further, oil holes communicating with the oil gallery of the engine, water holes communicating with the water jacket, and the like are formed in the substrates 1, 2 and the sub plate 3, but are not shown here.

The two substrates 1 and 2 have, for example, the same shape in plan view corresponding to the axial direction of the cylinder bore of the engine, but are formed symmetrically with respect to each other with the sub-plate 3 interposed therebetween. That is, for example, the bead 5 formed on the peripheral portion of the bore hole 4 is formed to have a downward convex shape on the upper substrate 1 shown in FIG. 3 are formed so as to face each other. Therefore, when the cylinder head and the cylinder block are connected via the metal gasket, the beads 5 are pressed against the sub-plate 3 and crushed, and the elastic force accompanying the deformation contributes to an increase in the surface pressure.

On the other hand, in the sub-plate 3, a shim plate 6 having a U-shaped cross section is attached to a peripheral portion of the bore hole 4. The shim plate 6 is a sub-plate for adjusting the plate thickness, that is, the surface pressure. As shown in FIG. 2, the shim plate 6 covers only the peripheral portion of the bore hole 4 of the sub-plate 3, and is formed in this embodiment. Then, a flat plate member projecting into the bore hole 4 is applied to the illustrated lower surface of the sub-plate 3, and the portion projecting from the bore hole 4 is folded back to the illustrated upper surface of the sub-plate 3 through the bore hole 4,
The folded portion is pressed and fixed to the sub-plate 3. Therefore, as shown in FIG. 1, the folded shim plate 6, the sub-plate 3, and the substrates 1 and 2 are present at the periphery of the bore hole 4 inside the bead 3 of the substrates 1 and 2, and the bead 5 is provided. Since there is only the shim plate 6, the sub-plate 3, and the substrates 1 and 2, and only the sub-plate 3 and the substrates 1 and 2 exist outside thereof, the total thickness is reduced in this order. become. Therefore, when the cylinder head and the cylinder block are connected to each other with the metal gasket interposed therebetween, the surface pressure gradually decreases in the order of the peripheral portion, the bead portion, and the outer portion in the immediate vicinity of the cylinder bore. Can be avoided. Further, the shim plate 6 is attached to the sub-plate 3 first, and then the sub-plate 3 is attached to the substrates 1 and 2, so that the positioning of the shim plate 6 becomes easy.

Further, in this embodiment, even in the peripheral portion of the same bore hole 4, the portion where the bore holes 4 are adjacent to each other (section A-
A), a shim plate folded back at each of the intermediate portion of the bolt hole 7 (cross section BB), the portion of the bolt hole 7 (cross section CC), and the portion slightly deviated from the bolt hole 7 (cross section DD) 6 and the sub plate 3 are configured such that the total plate thickness is different.
Specifically, the total thickness of the shim plate 6 and the sub plate 3 in the portion where the bore holes 4 are adjacent to each other is the largest as shown in FIG. 2B. This is because the rigidity between the adjacent cylinder bores is weak and the cylinder bores are easily deformed, and this portion is most likely to leak gas.

On the other hand, the total thickness of the folded shim plate 6 and the sub plate 3 at the bolt hole 7 is the smallest as shown in FIG. 2D, and the portion slightly deviated from the bolt hole 7 is shown in FIG. 2
As shown in FIG. 2e, the middle portion of the bolt hole 7 is slightly larger than that shown in FIG. 2c. That is, the total thickness of the folded shim plate 6 and the sub plate 3 gradually decreases from the middle portion of the bolt hole 7 to the portion of the bolt hole 7. This is mainly because the aluminum cylinder head bends when the bolt is tightened, and the surface pressure of the bolt hole 7 in the peripheral portion of the bore hole 4 tends to be high and the surface pressure of the intermediate portion of the bolt hole 7 tends to be low. The purpose is to reduce the surface pressure by reducing the plate thickness at the bolt hole 7 portion, and to increase the surface pressure by increasing the plate thickness at the intermediate portion of the bolt hole 7. By making the surface pressure of the peripheral portion of the bore hole 4 uniform in this way, it is possible to prevent the cylinder head from being excessively bent and to suppress the deformation of the cylinder bore to secure a perfect circle. is there.

In the present embodiment, when adjusting the total thickness of the shim plate 6 and the sub plate 3 folded as described above, the width of the folded portion of the shim plate 6 to be pressed is changed. Yes, it is. That is, if the width of the folded portion of the shim plate 6 is large, the surface pressure at the time of pressing between the sub-plate 3 and the folded portion of the shim plate 6 becomes small, and if the width is small, the surface pressure at the time of pressing becomes large. The amount by which the shim plate 6 sinks into the sub-plate 3 can be changed by pressurization, whereby the total thickness of the shim plate 6 and the sub-plate 3 in the folded portion after pressing can be changed around the bore hole. You can.
Therefore, the folded width of the shim plate 6 is large in the portion adjacent to the bore hole 4 where the total thickness of the folded shim plate 6 and the sub plate 3 is the largest, and then the middle portion of the bolt hole 7 and the portion slightly shifted from the bolt hole 7. The width of the folded portion of the shim plate 6 becomes smaller in the order of the bolt holes 7. Therefore, in this metal gasket, it is possible to change the total plate pressure of the folded shim plate 6 and the sub plate 3 at the periphery of the bore hole 4 without changing the pressing force of a pressing machine such as a press in a part. It becomes possible.

The adjustment of the total thickness of the folded-back shim plate 6 and the sub-plate 3 is not limited to the adjustment of the surface pressure at the time of pressing. For example, as shown in FIG. The thickness of the sub plate 3 may be adjusted. That is, FIG.
As shown in FIG. 4, for example, in the middle of the bolt hole 7 having the second largest plate thickness in the above description, as shown in FIG. 4A, the sub plate 3 corresponding to the folded portion of the shim plate 6 is slightly cut off and thinned. Next, in the portion slightly deviated from the bolt hole 7 having a small thickness, as shown in FIG. 4B, the sub-plate 3 is slightly cut away to make it thinner.
As shown in (2), the sub-plate 3 is further cut off and thinned. By doing so, the total thickness of the folded shim plate 6 and the sub-plate 3 can be changed only by subsequently folding the shim plate 6.

Note that, as described above, in the portion where the shim plate 6 is folded back with respect to the side to which the shim plate 6 is applied before the shim plate 6 is folded back, only that portion is the substrate 1 or the other portion. It will project to the two sides,
There is a possibility that the influence of the change in the plate thickness is biased only to that side. Therefore, as seen in the first prior art and as shown in FIG. 1B, the sub plate 3 and the shim plate 6 are formed, and the folded portion of the shim plate 6 and the shim plate 6 are attached to the sub plate 3. For example, in this example, a step 8 is formed on the sub
When a and 8b are formed, the influence of the thickness of the folded portion of the shim plate 6 and the thickness of the shim plate 6 alone also appears on the side to which the shim plate 6 is originally applied, and the surface pressure is balanced on both sides. By doing so, the stopper effect on the bead, the compressive deformation and the spring stress value are equal on both sides, and fatigue failure of the bead is not biased, and a stable seal can be provided for a long period of time.

Next, FIG. 5a shows a different embodiment of the metal gasket of the present invention. In this embodiment, the periphery of the bore hole of the shim plate 6 is independently folded, and the unfolded portion is fixed to the sub-plate 3 by spot welding, YAG laser welding, caulking, or the like. Even in this case, the periphery of the bore hole 4 inside the bead 3, the bead 5
Since the total thickness becomes smaller in the order of the part and the outside, the surface pressure at the time of assembling the engine gradually decreases in the order of the periphery near the cylinder bore, the bead part, and the outside thereof, and the surface pressure in the vicinity of the cylinder bore becomes extremely large. Therefore, various deformations can be avoided. Of course, since the shim plate 6 is attached to the sub-plate 3 first, the positioning of the shim plate 6 is easy.

In such a case, for example, FIG.
As shown in the figure, the change in the thickness of the folded portion of the shim plate 6 and the portion where the shim plate 6 is attached to the sub-plate 3
For example, in this example, the auxiliary plate 3
When the steps 8a and 8b are formed on the auxiliary plate 3, the influence of the thickness of the folded portion of the shim plate 6 and the thickness of the shim plate 6 alone appears.
On both sides so that fatigue failure of the bead is not biased and stable sealing can be achieved for a long period of time.

Also, as described above, even at the peripheral edge of the same bore hole 4, a portion where the bore holes 4 are adjacent to each other, an intermediate portion between the bolt holes 7, a portion of the bolt holes 7, and a portion slightly shifted from the bolt holes 7. Alternatively, the total thickness of the folded shim plate 6 and the sub plate 3 may be different. Further, the total thickness of the folded back shim plate 6 and the sub plate 3 may be gradually reduced from the middle portion of the bolt hole 7 to the portion of the bolt hole 7.

[0022]

As described above, according to the metal gasket according to the first aspect of the present invention, a sub-plate is laminated between a plurality of elastic metal plates each having a bead formed around a bore hole. At the same time, a shim plate having a bore hole periphery turned back is attached to the sub-plate, and the sum of the thickness of the substrate, the thickness of the sub-plate, and the thickness of the shim plate is determined by using the periphery of the bore hole, the beads, Department,
Since the surface pressure is gradually reduced in the order of the outer periphery of the bead portion, the peripheral pressure in the immediate vicinity of the cylinder bore, the bead portion, and the outside thereof, it is possible to avoid various deformations due to the extremely large surface pressure in the vicinity of the cylinder bore. In addition, it is possible to prevent the cylinder head from being bent, and to secure a perfect circle of the cylinder bore.

According to the metal gasket according to the second aspect of the present invention, the metal plate applied to one surface of the sub-plate is folded back to the other surface of the sub-plate to form the bore hole. In this configuration, the shim plate is placed over the peripheral edge of the base plate, so that when this sub-plate is attached to the substrate, the shim plate is automatically positioned with respect to the substrate. Further, according to the metal gasket according to claim 3 of the present invention, the folded back portion of the shim plate is pressed against the sub plate, and the surface pressure is changed at the periphery of the bore hole, so that the folded shim plate and the sub plate are changed. The thickness of the cylinder bore is changed at the periphery of the bore hole, so that the surface pressure at the periphery of the cylinder bore can be adjusted, thereby preventing the cylinder head from bending and securing the cylinder cylinder's perfect circle. .

According to the metal gasket of the fourth aspect of the present invention, the surface pressure at the time of pressing is changed at the periphery of the bore hole by changing the width of the folded portion of the shim plate. It is possible to change the total plate pressure of the folded-back shim plate and the sub-plate at the periphery of the bore hole without changing the pressing force of the pressing machine such as a part at a partial portion.

Further, according to the metal gasket of the present invention, the periphery of the bore hole of the shim plate is folded back in advance, and the unfolded portion of the shim plate is fixed to the sub plate. As a result, the positioning of the substrate, the auxiliary plate, and the shim plate becomes easy. Further, according to the metal gasket according to claim 6 of the present invention, since the width of the folded portion of the shim plate is changed at the periphery of the bore hole, the surface pressure of the periphery of the cylinder bore can be adjusted.

Further, according to the metal gasket according to the seventh aspect of the present invention, by changing the thickness of the sub-plate corresponding to the folded portion of the shim plate at the periphery of the bore hole, the folded-up shim plate and the sub-plate are changed. Because the plate thickness with the plate is changed at the periphery of the bore hole, the surface pressure of the peripheral portion of the cylinder bore can be adjusted, thereby preventing the cylinder head from bending,
It is possible to secure the perfect circle of the cylinder bore.

According to the metal gasket of the present invention, the change in the thickness of the folded portion of the shim plate and the change in the thickness of the attachment portion between the shim plate and the sub-plate are equal on both sides of the sub-plate. Since the sub-plate and the shim plate are formed at the same time, the surface pressure is balanced on both sides, and a stable seal can be obtained for a long period.

[Brief description of the drawings]

FIG. 1 is a longitudinal sectional view showing one embodiment of a metal gasket of the present invention.

2 (a) is a bottom view, FIG. 2 (b) is a sectional view taken along line AA, FIG. 2 (c) is a sectional view taken along line BB, and FIG. FIG. 3C is a cross-sectional view, and FIG.

FIG. 3 is a longitudinal sectional view showing a different embodiment of the metal gasket of the present invention.

FIG. 4 is a longitudinal sectional view of a sub-plate used for the metal gasket of FIG.

FIG. 5 is a longitudinal sectional view showing another embodiment of the metal gasket of the present invention.

[Explanation of symbols]

 Reference numerals 1 and 2 are substrates 3 is a sub plate 4 is a bore hole Linder bore hole 5 is a bolt hole 6 is a shim plate 7 is a bolt hole 8a and 8b is a step

Claims (8)

[Claims] 1. A metal gasket interposed between a block member and a head member joined by bolts, wherein the metal gasket is formed between a plurality of elastic metal plates having beads formed around a bore hole. Along with stacking the sub-plates, attached to the sub-plates are shim plates with bead hole peripheral parts turned back,
The sum of the thickness of the substrate, the thickness of the sub-plate, and the thickness of the shim plate,
A metal gasket, which is smaller in the order of a bore hole peripheral portion, a bead portion, and an outer side of the bead portion. 2. The shim plate according to claim 1, wherein the metal plate applied to one surface of the sub-plate is folded over the other surface of the sub-plate, and is covered on the periphery of the bore hole. The metal gasket according to claim 1, characterized in that: 3. The folded portion of the shim plate is pressed against the sub-plate, and the surface pressure is changed at the periphery of the bore hole, so that the thickness of the folded shim plate and the sub-plate changes at the periphery of the bore hole. The metal gasket according to claim 2, wherein: 4. The metal gasket according to claim 3, wherein the surface pressure at the time of pressing is changed at the periphery of the bore hole by changing the width of the folded portion of the shim plate. 5. The metal gasket according to claim 1, wherein the shim plate is formed by independently folding a peripheral portion of a bore hole, and an unfolded portion is fixed to the sub-plate. 6. The metal gasket according to claim 5, wherein the width of the folded portion of the shim plate changes at the periphery of the bore hole. 7. The plate thickness of the folded back shim plate and the sub plate changes at the periphery of the bore hole by changing the plate thickness of the sub plate corresponding to the folded portion of the shim plate at the periphery of the bore hole. 7. The metal gasket according to claim 2, wherein the metal gasket is a metal gasket. 8. A change in the thickness of at least one of the thickness changes occurring at the folded portion of the shim plate and the attachment portion between the shim plate and the sub-plate becomes equal on both sides of the sub-plate. 8. The metal gasket according to claim 2, wherein the auxiliary plate and the shim plate are formed as described above.