JPH0960729A - Metallic cylinder head gasket - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent oil beads from being permanently set, and also prevent lubricant from leaking even if there are flaws close to the outer circumference over the upper surface of a cylinder block or the lower surface of a cylinder head. SOLUTION: Leak of cooling water passing through water holes 5 is tried to be prevented by water beads 9 formed at the inner sides rather than by cylinder beads 7 around bore holes 3, oil holes 4 and bolt holes 6. Leak of lubricant passing through the oil holes 4 is tried to be prevented by the oil beads 8 formed around the respective oil holes 4. Each oil bead 8 is prevented from being permanently set by bridging beads 18 formed close to the tip end rather than the oil beads 8.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION A metal cylinder head gasket according to the present invention is sandwiched between an upper surface of a cylinder block of an engine and a lower surface of the cylinder head to maintain airtightness and liquid tightness between the two surfaces.

[0002]

2. Description of the Related Art A cylinder head gasket is sandwiched between an upper surface of a cylinder block and a lower surface of a cylinder head which form an engine, and a high pressure combustion gas generated in a cylinder and a flow between the cylinder block and the cylinder head. Prevent the lubricating oil and cooling water from leaking to the outside. In recent years, as such a cylinder head gasket, a metal cylinder head gasket made of a thin metal plate having elasticity such as a galvanized steel plate or a stainless steel plate is often used. Further, many publications describing such a cylinder head gasket have existed conventionally, as described in, for example, Japanese Utility Model Publication No. 4-16026.

The metal cylinder head shown in FIG. 2 is an example of a metal cylinder head gasket that has been conventionally used. The metal cylinder head gasket 1 is composed of at least one (usually two or three or more) metal thin plates 2. This thin metal plate 2
(When aligning a plurality of metal thin plates, the positions of the metal thin plates are aligned with each other), the bore holes 3 and 3, the oil holes 4 and 4 which are the first through holes, and the second through holes are provided. Water holes 5, 5
And bolt holes 6 and 6 are formed. The bore holes 3 and 3 of these holes are aligned with the cylinder holes opened at the top of the cylinder block. Further, the oil holes 4 and 4 allow the lubricating oil, which is the first fluid, flowing between the cylinder block and the cylinder head to pass therethrough. In addition, the water holes 5, 5
Allows the cooling water, which is the second fluid, flowing between the cylinder block and the cylinder head to pass through. Furthermore,
Bolts for connecting the cylinder head and the cylinder block are inserted into the bolt holes 6, 6.

Cylinder beads 7, 7 serving as contact pressure improving means are provided on the peripheral portions of the bore holes 3, 3 respectively.
3 is formed so as to surround the entire circumference. In the drawings of the present application, each bead is shown by a chain line for simplification, but each bead has a bent cross-sectional shape as shown in FIG. 3 (A) or (B) described later. Have. The cylinder beads 7, 7 are a part of the thin metal plate 2, and each of the bore holes 3,
The position surrounding the entire circumference of 3 is formed by curving the cross-sectional shape as shown in FIG. Due to the presence of such cylinder beads 7, 7, the contact pressure at the peripheral edge of each of the bore holes 3, 3 becomes high over the entire circumference, and the high-pressure combustion gas generated in the cylinder holes leaks to the outside. Prevent doing.
In the case of a metal cylinder head gasket formed by laminating two or more thin metal plates, a part of the thin metal plates is folded back at the peripheral edge of the bore hole, and the thickness of the peripheral edge of the bore hole is set to be smaller than that of the other part. The contact pressure improving means may be used by slightly increasing the contact pressure. In this case, a cylinder bead may be used together.

Oil beads 8 and 8 as the first beads are provided around the oil holes 4 and 4 and the bolt holes 6 and 6 adjacent to the oil holes 4 and 4, respectively. 4 and the bolt holes 6, 6 are formed so as to surround them. As the cross-sectional shape of the oil beads 8 and 8, a curved shape as shown in FIG. 3 (A) and a shape as shown in FIG. 3 (B) can be adopted. The bead having the cross-sectional shape shown in FIG. 3B is a so-called diaphragm bead, and is formed by connecting flat portions adjacent to each other on the inner peripheral side and the outer peripheral side with inclined portions. The contact pressure obtained by such a diaphragm bead is lower than the contact pressure obtained by the bead as shown in FIG. 3 (A), but the sealing property required at the peripheral portions of the oil holes 4 and 4 is not sufficient. However, it is lower than the sealing property required for the peripheral portions of the bore holes 3, 3. Therefore, the oil beads 8 and 8 may be the diaphragm beads.

Further, a water bead 9 which is a second bead is formed on the outer peripheral edge of the metal thin plate 2 over the entire circumference. Similar to the oil beads 8 and 8, the water beads 9 are also mountain-shaped beads having a curved shape as shown in FIG. 3 (A) or diaphragm beads as shown in FIG. 3 (B). The water bead 9 thus formed on the outer peripheral edge of the thin metal plate 2 is combined with the cylinder bead 7, 7 and the oil bead 8 to leak the cooling water passing through the water holes 5, 5. Prevent.

It is to be noted that the metal thin plate 2 is formed with protrusions 10 and 10 which are protruded to the outside, and the oil holes 4 and 4 are formed.
Is formed on each of these protrusions 10, 10. When using a metal cylinder head gasket, these protrusions 1
Nos. 0 and 10 are used in a state of being sandwiched between the end faces of the protrusions protruding from the side faces of the cylinder block and the cylinder head. That is, in some engines, as shown in FIG. 4, the cylinder block 11 and the cylinder head 1
Projections 13 and 14 are formed on the side surface of No. 2. And, these cylinder block 11 and cylinder head 12
Lubricating oil flow paths 16 and 17 for circulating lubricating oil between
Are opened at the end faces of these protrusions 13 and 14.

Further, a part of the water bead 9 passes through a portion between the tip edges of the protrusions 10, 10 and the oil beads 8, 8 formed around the oil holes 4, 4. There is. Therefore, the tip edges of the protrusions 10, 10 and the oil holes 4,
The oil beads 8 and 8 and the water beads 9 are present as a double bead having a cross-sectional shape as shown in FIG. 5, for example. In this way, each of the protrusions 10, 10
The reason for forming a double bead in the portion between the tip edge of the oil holes 4 and the oil holes 4 and 4 is to secure the sealing property between the end surfaces of the projecting portions 13 and 14 which are easily deformed. That is, the protrusions 13 and 14 protruding from the side surface of the cylinder block 11 or the cylinder head 12 have low rigidity against the repulsive force caused by compressing the metal cylinder head gasket 1.
It is easy to deform in the direction indicated by arrow α in FIG. Further, during operation of the engine, combustion (explosion) that is repeatedly performed in the cylinder hole tends to expand or contract the distance between the end faces of the protrusions 13 and 14.

Therefore, if no measures are taken, the bead existing in the above-mentioned portion is repeatedly beaten between the above-mentioned end faces, the bead existing in the above-mentioned portion is dented early, and the sealing property by the bead is secured. Becomes difficult. Therefore, even if the beads of the above-mentioned space portion are doubled and the above-mentioned bead 8 and 9 portions are sufficiently stretched between the end faces and repeatedly beaten between the end faces, these bead 8,
9 makes it hard to get tired.

[0010]

However, in the case of the conventional metal cylinder head gasket constructed as described above, there are the following points to be solved. That is, the upper surface of the cylinder block or the lower surface of the cylinder head may be slightly scratched when the cylinder block or the cylinder head is manufactured. Further, such a scratch is likely to be formed on the outer peripheral portion of each surface. On the other hand, the distance L (FIG. 4) between the tip edges of the protrusions 13 and 14 and the opening peripheral edges of the lubricating oil flow paths 16 and 17 is only about 6 to 8 mm. Therefore, when there is a scratch between the tip edges of the protrusions 13 and 14 and the peripheral edges of the openings of the lubricating oil flow paths 16 and 17, a part of the oil bead 8 or the water bead 9 is damaged by the scratch. The likelihood of matching increases. In particular, there is a high possibility that the water bead 9 formed near the outer periphery will match the scratch. Then, when the water bead 9 is aligned with the scratch, the sealing of the cooling water passing through the water holes 5 and 5 becomes incomplete and cooling water leakage easily occurs. The metal cylinder head gasket of the present invention was invented in view of such circumstances.

[0011]

The metal cylinder head gasket of the present invention satisfies all of the following requirements.
Among these requirements, requirements (1) to (4) are the same as those of the conventional metal cylinder head gasket described above, but the metal cylinder head gasket of the present invention solves the above-mentioned problems by providing the requirements. A bore hole formed of at least one thin metal plate and aligned with a cylinder hole opened at the top of the cylinder block, and a first transparent member for passing a first fluid flowing between the cylinder block and the cylinder head. A hole, a second through hole for passing a second fluid flowing between the cylinder block and the cylinder head, a bolt hole for inserting a bolt for connecting the cylinder head and the cylinder block, and And a contact pressure improving means for increasing the contact pressure at the peripheral portion of the bore hole over the entire circumference of the bore hole. At the time of use, at least one first through hole is sandwiched between the upper surface of the cylinder block and the lower surface of the cylinder head, each of which has a protruding portion on a part of each side surface, while being positioned between the protruding portions. It In order to prevent the leakage of the first fluid, the first bead formed by bending the cross-sectional shape of the metal thin plate is present in a state of surrounding the entire circumference of the first through hole. In order to prevent the leakage of the second fluid, the second bead formed by bending the cross-sectional shape of the metal thin plate, between the second through hole and the peripheral portion of the metal thin plate, The second fluid is present inside the first through hole, and the second through hole is present between the second bead and the contact pressure improving means, thereby providing the second fluid. The leakage is prevented. A third bead formed by bending the cross-sectional shape of the thin metal plate is present at the tip of the portion of the thin metal plate that is sandwiched by the protrusions. When the metal cylinder head gasket is used, the metal cylinder head gasket is clamped between the tip ends of the protrusions.

[0012]

In the case of the metal cylinder head gasket of the present invention configured as described above, the third bead that is provided in parallel with the first bead that is sandwiched between the protrusions is provided together with the first bead. It is stretched between the end faces of the protrusion to prevent the first bead from sagging. If there is a scratch on the tip end of the protrusion, this scratch and the third bead may be aligned, but this third bead prevents the first bead from sagging. It is provided only for the purpose of having no function of sealing fluid. Therefore, even if the end portion of the projecting portion near the tip of the end surface is scratched, the poor sealing property does not occur.

[0013]

FIG. 1 shows an embodiment of the present invention. The feature of the metal cylinder head gasket of the present invention is that the oil beads 8, 8 as the first bead and the water bead 9 as the second bead have been devised in the installation positions, and further the third bead, the striking bead. 18 and 18 are provided independently of the oil beads 8 and 8 and the water beads 9. Since the configuration and operation of the other parts are the same as those of the conventional structure described above, the same parts are designated by the same reference numerals to omit or simplify the overlapping description, and the characteristic parts of the present invention will be mainly described below. .

The oil beads 4 are formed around the oil holes 4 and 4 which are the first through holes so as to surround the entire circumference of the oil holes 4 and 4 to form a first fluid. We are trying to prevent the leakage of lubricating oil. Particularly, in the case of the illustrated embodiment, unlike the case of the above-described conventional structure, the oil beads 8 and 8 are provided only in the peripheral portions of the oil holes 4 and 4. In other words, the bolt holes 6, 6 are arranged outside the oil beads 8, 8. The cross-sectional shape of each of these oil beads 8 is
It is one of FIGS. 3 (A) and 3 (B).

The water bead 9 which is the second bead, which is provided to prevent the leakage of the cooling water which is the second fluid, includes the bore holes 3, 3 and the water holes 5, 5 and the peripheral portion of the metal thin plate 2. Between
The oil holes 4 and 4 and the bolt holes 6 and 6 are present on the inner side (the central portion of the thin metal plate 2) over the entire circumference. By providing the endless water bead 9 at such a position, each of the water holes 5 and 5 is formed by the cylinder beads 7 and 7 formed around the bore holes 3 and 3 and the water bead 9. It comes to exist in the part sandwiched from both inside and outside.
Therefore, the leakage of the cooling water flowing inside the water holes 5 and 5 is prevented by the cylinder beads 7 and 7 and the water bead 9.

Further, a protrusion 1 is formed on a part of the thin metal plate 2.
0 and 10 are formed. When the metal cylinder head gasket 1 is used, these protrusions 10 and 10 are
As shown in, protruding from the side surface of the cylinder block 11,
It is sandwiched between the upper end surface of the protruding portion 13 and the lower end surface of the protruding portion 14 protruding from the side surface of the cylinder head 12. At the tip of each of the protrusions 10 and 10 closer to the tip than the oil bead 8 is provided a tension bead 18, 18.
The protrusions 10 and 10 are formed so as to penetrate from one circumferential edge to the other circumferential edge. When using the metal cylinder head gasket 1, each of these tension beads 18,
18 is sandwiched between the upper and lower front end portions of the protruding portions 13 and 14 protruding from the side surfaces of the cylinder block 11 and the cylinder head 12.

In the case of the metal cylinder head gasket 1 of the present invention configured as described above, the oil beads 8 and 8 held between the protrusions 13 and 14 protruding from the side surfaces of the cylinder block 11 and the cylinder head 12 are provided. Stretching beads 18, 18 provided in parallel with the above and the oil beads 8, 8 are stretched between the upper and lower surfaces of the projecting portions 13, 14. As a result, only the oil beads 8 and 8 are prevented from being strongly beaten between these two surfaces, and the oil beads 8 and 8 are prevented from sagging. Each of the protrusions 13,
If the top and bottom end surfaces of 14 are scratched near the tip, the scratch and the bead 18, 18 may be aligned with each other. However, these thrust beads 18, 18 are
It is provided only to prevent the oil beads 8 and 8 from sagging, and does not serve to seal lubricating oil or cooling water. Therefore, even when the upper and lower end surfaces of the respective protruding portions 13 and 14 are scratched near the tips of the upper and lower end surfaces, defective sealing does not occur.

In the case of the embodiment shown in the figures, the above-mentioned striking beads 18 and 18 are formed at the tips of the projecting portions 10 and 10, and both ends of these striking beads 18 and 18 are provided at the projecting portions 10 and 18, respectively. It is formed by penetrating to both end edges in the circumferential direction of 10. Therefore, this strut bead 18, 1
By forming 8, the local stress is not generated in the metal thin plate 2, and the deformation of the metal thin plate 2 can be prevented. There is also a metal cylinder head gasket in which the planar shape of the metal thin plate 2 is larger than the upper surface of the cylinder block 11 and the lower surface of the cylinder head 12. In the case of such a metal cylinder head gasket, the protrusions 13 and 14 described above are used.
The portion separated from the above protrudes from the outer side surfaces of the cylinder block 11 and the cylinder head 12. When forming the above-mentioned striking bead 18 on the metal cylinder head gasket having such a large planar shape, the striking bead 18 is made endless and is formed over the entire circumference of the outer peripheral edge portion of the metal thin plate 2. You can also In short, in order to prevent the metal thin plate 2 from being deformed by forming the strut bead 18, the end portion of the strut bead 18 does not exist inside the outer peripheral edge of the metal thin plate 2.

[0019]

Since the metal cylinder head gasket of the present invention is constructed and operates as described above, even if the end portions of the end faces of the protrusions formed on the cylinder block and the cylinder head are scratched, It is possible to sufficiently secure the sealing property of the portion. Moreover, it is possible to prevent the bead held between the portions from sagging, and to maintain the sealing property in a good state for a long period of time.

[Brief description of drawings]

FIG. 1 is a partial plan view showing an embodiment of the present invention.

FIG. 2 is a partial plan view showing a conventional example.

FIG. 3 is a partially enlarged sectional view showing two examples of sectional shapes of beads.

FIG. 4 is a cross-sectional view of a protrusion formed on a side surface of a cylinder block and a cylinder head.

FIG. 5 is a sectional view showing an example of a double bead formed on a protruding portion of a metal cylinder head gasket.

[Explanation of symbols] 1 metal cylinder head gasket 2 metal thin plate 3 bore hole 4 oil hole 5 water hole 6 bolt hole 7 cylinder bead 8 oil bead 9 water bead 10 protrusion 11 cylinder block 12 cylinder head 13, 14 protrusion 15 lubrication Oil 16, 17 Lubricating oil flow path 18 Stretching bead

Claims (1)

[Claims] 1. A metal cylinder head gasket satisfying all of the following requirements. A bore hole formed of at least one thin metal plate and aligned with a cylinder hole opened at the top of the cylinder block, and a first transparent member for passing a first fluid flowing between the cylinder block and the cylinder head. A hole, a second through hole for passing a second fluid flowing between the cylinder block and the cylinder head, a bolt hole for inserting a bolt for connecting the cylinder head and the cylinder block, and And a contact pressure improving means for increasing the contact pressure at the peripheral portion of the bore hole over the entire circumference of the bore hole. At the time of use, at least one first through hole is sandwiched between the upper surface of the cylinder block and the lower surface of the cylinder head, each of which has a protruding portion on a part of each side surface, while being positioned between the protruding portions. It In order to prevent the leakage of the first fluid, the first bead formed by bending the cross-sectional shape of the metal thin plate is present in a state of surrounding the entire circumference of the first through hole. In order to prevent the leakage of the second fluid, the second bead formed by bending the cross-sectional shape of the metal thin plate, between the second through hole and the peripheral portion of the metal thin plate, The second fluid is present inside the first through hole, and the second through hole is present between the second bead and the contact pressure improving means, thereby providing the second fluid. The leakage is prevented. A third bead formed by bending the cross-sectional shape of the thin metal plate is present at the tip of the portion of the thin metal plate that is sandwiched by the protrusions. When the metal cylinder head gasket is used, the metal cylinder head gasket is clamped between the tip ends of the protrusions.