JPH0469462A - Cylinder head gasket - Google Patents

Abstract

PURPOSE:To ensure good seal performance around a cooling water hole by providing a seal member in the periphery of the cooling water hole, and setting thickness in a combustion chamber hole side larger than the thickness in an opposite side, of the seal member. CONSTITUTION:When a cylinder block is tightened to a cylinder head, a cooling water hole seal member 32 further thinner than a combustion chamber hole seal member 31 is closely attached to the cylinder block and the cylinder head to cut off communication between a combustion chamber hole 11 and a cooling water hole 12. Further in the cooling water hole seal member 32, thickness Tn in a side of a bead 15, providing a large clearance between the cylinder block and the cylinder head and of a high pressure side, is set large as compared with the thickness. To in an outer side part, providing a small clearance between the cylinder block and the cylinder head, so that the seal member is closely attached uniformly relating to a titled junction surface to obtain an almost equal surface pressure over the total periphery of the cooling water hole seal member 32.

Description

Detailed Description of the Invention [Field of Industrial Application] The present invention relates to a cylinder head gasket interposed between a cylinder head and a cylinder block of an internal combustion engine, and particularly relates to a cylinder head gasket interposed between a cylinder head and a cylinder block of an internal combustion engine. This relates to a cylinder head gasket with water holes.

[Prior Art] It is well known that gaskets are interposed between joint members to prevent pressure fluid from leaking from joint surfaces. For example, a cylinder head gasket interposed between a cylinder head and a cylinder block of an internal combustion engine is required to simultaneously seal combustion gas, cooling water, and lubricating oil. Especially for combustion gas, high temperature,
Sealing is difficult not only because of the high pressure but also because of the large temperature and pressure changes. For this reason, various gaskets have been proposed, and recently, metal gaskets made of metal plates, ie, metal gaskets, have been attracting attention. Specifically, multiple holes are drilled in a metal substrate through which pressurized fluid such as combustion gas passes, and a bead is formed in the substrate around each hole to ensure high surface pressure against the bonding members. This is what I did to get it. Regarding such cylinder head gaskets, for example, Japanese Utility Model Application No. 64-8556 proposes that a soft sealing member be provided at the base of the bead on the water hole side to prevent corrosion due to water penetration. ing.

[Problems to be Solved by the Invention] In the cylinder head gasket described in the above-mentioned publication, a sealing member is provided at the base of the bead, that is, at the hem, so that the sealing performance against combustion gas is improved. However, sufficient consideration is not necessarily given to the sealing properties around the cooling water holes, and the outside of the sealing member, that is, the side opposite to the bead, is filled with cooling water up to the outer edge of the board.
For example, problems such as corrosion of the cylinder head progressing and cooling water becoming more likely to become contaminated may occur.

Therefore, it is desirable to provide a seal member to surround the cooling water hole, but when the cylinder head and cylinder block are tightened, due to the positional relationship of their joints, there is a gap between the two on the combustion chamber hole side and the opposite side. The gap is different and the one on the combustion chamber hole side becomes a dog.

For this reason, it is not preferable to simply surround the cooling water hole in the vehicle with a sealing member of the same thickness, as this will result in a difference in surface pressure between the combustion chamber hole side and the opposite side. Furthermore, when a sealing member is provided to surround multiple cooling water holes, the sealing member must be attached to some or each of the cooling water holes to the board, and the sealing member must be attached to the substrate to surround the combustion chamber. Since it has to be attached to the small-diameter hole openings in larger numbers than the holes, workability is poor and costs increase.

Therefore, the present invention provides a cylinder head gasket in which a plurality of combustion chamber holes through which at least combustion gas passes and a plurality of cooling water holes through which cooling water passes are bored in a metal substrate. The purpose is to ensure sealing performance. Another object of the present invention is to enable sealing members to be efficiently disposed around the cooling water holes.

[Means for Solving the Problems] In order to achieve the above object, the present invention provides a metal substrate having at least a combustion chamber hole through which combustion gas passes and a cooling water hole through which cooling water passes. In the cylinder head gasket, a sealing member is provided around the cooling water hole, and the thickness of the sealing member on the combustion chamber hole side is made smaller than the thickness on the opposite side.

The present invention also provides a cylinder head gasket in which a plurality of combustion chamber holes through which at least combustion gas passes and a plurality of cooling water holes through which cooling water passes are formed in a metal substrate, in which the plurality of cooling water holes are provided. A sealing member is provided so as to surround at least some of the cooling water holes in a continuous line.

Note that the sealing member may be a vulcanized rubber layer attached to the substrate. Further, it is preferable to form a non-vulcanized rubber layer on the entire surface of the substrate including the sealing member.

[Operation] When the cylinder head gasket having the above configuration is interposed between the cylinder head and the cylinder block and the two are fastened together with a predetermined tightening force, the sealing member provided around the cooling water hole Since the thickness on the side of the combustion chamber hole is larger than the thickness on the outer edge side of the board on the opposite side, the sealing member is in close contact with the joint surface when the cylinder head and cylinder block are connected, and the sealing member is in close contact with the joint surface around the cooling water hole. A substantially concave surface pressure can be obtained.

If a sealing member is provided around the plurality of cooling water holes, it should be provided so that a continuous line surrounds at least a portion, for example, half of the cooling water holes, and the same applies to the remaining half of the cooling water holes. Provided for. Therefore, if the sealing member is provided using two nozzles, for example, the sealing member can be provided around the entire cooling water hole, making the work easier.

[Example 1] Hereinafter, an example of the cylinder head gasket of the present invention will be described with reference to the drawings.

1 and 3 show the bottom surface of a cylinder head gasket interposed between a cylinder head and a cylinder block of a multi-cylinder internal combustion engine, with the front side of the paper representing the cylinder block side. Hereinafter, for convenience of explanation, explanation will be given first with reference to FIGS. 3 to 7.

In FIG. 3, the cylinder head gasket 1 has a base plate 10 made of an elastic metal plate, for example, a stainless steel plate, and a combustion chamber hole 11 and the like are formed in the base plate 10, and a bead 1
5. Slanted portions 16 to 18 are formed. A plurality of cooling water holes 12 and lubricating oil holes 13 are bored in the substrate 10 . Note that the cooling water hole 12 has a smaller diameter than the opening area of a cooling water channel (not shown) formed in the cylinder block, and forms a diaphragm. This is to set a predetermined diameter according to each cooling waterway in order to adjust the effective cross section of the cooling waterway. Furthermore, a plurality of bolt holes 14 are bored around the combustion chamber hole 11 at substantially equal intervals.

As is clear from FIGS. 4 to 6, a bead 15 is formed around the combustion chamber hole 11, and in this embodiment, the convex portion 15a is on the cylinder block side and the concave portion 15b is on the cylinder head side. will be placed in As shown in FIG. 3, beads 1515 formed around adjacent combustion chamber holes 11.11 are connected to each other via a gathering portion 15c, and the width of the gathering portion 15c is equal to the width of each of the beads 1515 that gather. It is set to be smaller than the width and gradually decrease as it reaches the center. Further, as is clear from FIG. 7 showing the cross-section of ■-■ in FIG. A sloped portion 18 shown in FIG. 3 is formed to surround the oil hole 13, and a sloped portion 17 forming an angle β with the adjacent portion is formed on the outer edge of the substrate 10 to surround all the holes.
is formed. Incidentally, these inclined portions 16 to 18 correspond to the inclined portion on one side of the bead 15 and are therefore called a half bead. The substrate 10 from the bead 15 to the combustion chamber hole 11 is formed with a flat open end 10a, and a ring-shaped metal plate,
For example, a spacer made of stainless steel plate, the so-called shim ring 20
is fixed.

As shown in the cross-sectional views of FIGS. 5 to 7, a vulcanized rubber layer 30 made of vulcanized fluorine rubber is formed on the entire surface of the substrate 10 and shim ring 20. And bead 1
A combustion chamber hole sealing member 31 made of vulcanized fluororubber is formed so as to overlap with the hem edge of the convex portion 15a of 5 and continue along the bead 15, and a cooling water made of the same material is formed around the cooling water hole 12. A hole sealing member 32 is formed. The combustion chamber hole sealing member 31 is shown by a two-dot chain line in FIGS. 1 and 3, and the cooling water hole sealing member 32 is shown by a broken line in the same figure. As shown in FIG. 5, a predetermined booth fid exists between the two, and the thickness T1 of the combustion chamber hole sealing member 31 is set to be smaller than the thickness T2 of the cooling water hole sealing member 32. Furthermore, in order to ensure sealing performance when joining the cylinder block and cylinder head, the entire surfaces of the combustion chamber hole sealing member 31, the cooling water hole sealing member 32, the shim ring 20, and the substrate 10 are coated with unvulcanized or non-vulcanized material. Vulcanized rubber layer 3
3 is formed. Here, unvulcanized rubber refers to rubber that does not contain a vulcanizing agent, and unvulcanized rubber refers to rubber that contains a vulcanizing agent but has not been subjected to vulcanization treatment.

Therefore, although unvulcanized rubber initially has the same characteristics as unvulcanized rubber, vulcanization progresses during use and a strong rubber layer is formed.

The vulcanized rubber layer 30, the combustion chamber hole sealing member 31, and the cooling water hole sealing member 32 are made of fluorine-based non-vulcanized rubber with a vulcanizing agent added thereto, coated on the substrate 10, and then heated at a predetermined temperature. It can be formed by vulcanization. Incidentally, the combustion chamber hole sealing member 31 and the cooling water hole sealing member 32 in this embodiment both have the convex portion 15a of the beat 15.
Since the shim ring 20 is welded to one side of the substrate 10 and then formed as a vulcanized rubber layer on the same surface, manufacturing is easy.

Next, the cooling water hole sealing member 32 will be described in detail with reference to FIGS. 1 and 2. FIG. 1 shows the bottom surface of both ends of the cylinder head gasket 1 excluding the center part, and the cooling water hole sealing member 32 is a sealing member 32a provided approximately in two on both left and right sides, that is, on the intake side and the exhaust side.

32b. These seal members 32a.

Each of 32b is formed by one continuous line. That is, the fluororubber material constituting the seal members 32a, 32b is discharged from a nozzle (not shown) at a predetermined rate, and as this nozzle moves relatively along the curve shown in FIG. 1, the seal members 32a, 32b are attached and formed around the left and right cooling water holes 12 of the substrate 10, respectively, in a stroke-like manner. For example, if a pair of nozzles are arranged in parallel above the left and right sides of FIG. 1, and the movement is controlled along a predetermined trajectory stored in advance, a rubber material can be discharged from each pair of nozzles at a predetermined rate. , seal members 32a and 32b are formed on both the left and right sides as shown in FIG. By setting the discharge amount of the rubber material on the combustion chamber hole 11 side (inside in FIG. 1) to be larger than that on the outside, a seal member 32a having a cross-sectional shape as shown in FIG. 2 is formed. be able to.

That is, the combustion chamber hole 11 side of the seal member 32a (in FIG.
The thickness Tn of the flat part on the outside (on the right in Figure 2)
The thickness TO can be set larger than the thickness TO of the portion located at .

When a fastening force is applied to the cylinder head gasket 1 configured as described above, first the convex portion 1 of the bead 15 shown in FIG.
5a comes into contact with the joint surface of the cylinder block, and the beat 15
is deformed. Then, the shim ring 20 and the open end 10
When the bead 15 is tightened between the cylinder block and the cylinder head, the bead 15 will not deform any further and will come into close contact with both with its elastic restoring force. Since the bolt fastening position is separated from the combustion chamber hole 11, when the cylinder block and cylinder head are tightened, the bolt tightening position is separated from the combustion chamber hole 11.
The combustion chamber hole 11 and the substrate 1 on the opposite side compared to the gap between the two sides.
The gap between the two on the outer edge side of 0 becomes narrower. That is, the gap between the cylinder block and the cylinder head gradually decreases from the combustion chamber hole 11 to the outer edge side of the substrate 10, and the joint surface with the cylinder head gasket becomes a gently sloped surface.

Therefore, the combustion chamber hole sealing member 31 comes into close contact between the two. At the same time, the cooling water hole sealing member 32 (T2<TI), which is thinner than the combustion chamber hole sealing member 31, is brought into close contact with the cylinder block and cylinder head, and the combustion chamber hole 1
1 and the cooling water hole 12 is cut off. Moreover, as described above, the cooling water hole sealing member 32 has a large gap between the cylinder block and the cylinder head compared to the thickness To of the outer part where the gap between the cylinder block and the cylinder head is small after bolts are fastened. In addition, since the thickness Tn of the bead 15 side, which is the high pressure side, is set to be large, it adheres evenly to the inclined joint surface, and the contact pressure between the passages can be achieved over the entire length of the cooling water hole sealing member 32. It will be done.

From the viewpoint of the sealing function for the combustion chamber hole 11, the shim ring 20 maintains the sealing ability of the bead 15, and the shim ring itself functions as a sealing member. It forms a seal and ensures stable sealing performance against combustion gas. At the same time, good sealing performance for the cooling water is ensured by the cooling water hole sealing member 32 and the combustion chamber hole sealing member 31. That is, the combustion chamber hole sealing member 31 and the cooling water hole sealing member 32 are in close contact with the attached joint surface, and the sealing function on the combustion chamber hole 11 side against high-pressure combustion gas is achieved.
Appropriate sealing performance corresponding to the sealing function of the cooling water hole 12 side against low-pressure cooling water can be ensured. Moreover,
Since the unvulcanized or non-vulcanized rubber layer 33 is formed on the entire surface of the cylinder head gasket 1, the sealing performance is not impaired even if minute irregularities exist on the joint surface of the cylinder block and the cylinder head.

In the above-described embodiment, the cylinder head gasket 1 was arranged so that the convex part 15a of the bead 15 was on the cylinder block side, but it was turned upside down and arranged so that the convex part 15a was on the cylinder head side. It may also be a thing. In addition, only the cooling water hole sealing member 32 is attached to the bead 15.
It may also be formed by adhering to the surface of the concave portion 15b side.

Furthermore, the thickness of the seal members 32a, 32b may be changed between the intake side and the exhaust side (for example, the thickness on the exhaust side may be made thicker).

[Effects of the Invention] Since the present invention is configured as described above, it produces the effects described below.

That is, in the cylinder head gasket of the present invention,
Since the sealing member is thicker on the combustion chamber hole side or on the opposite side, it evenly contacts the joint surface between the cylinder head and the cylinder block, and the cooling water is reliably sealed.

In addition, in cylinder head gaskets in which a sealing member is provided so as to surround the cooling water hole in a continuous line, the sealing member can be provided with good workability, making mass production possible and reducing costs. It can be suppressed.

[Brief explanation of the drawing]

FIG. 1 is a bottom view of a part of a cylinder head gasket according to an embodiment of the present invention, FIG. 2 is a sectional view taken along the line II-II in FIG. 1, and FIG. 3 is a cylinder according to an embodiment of the present invention. FIG. 4 is a bottom view of a part of the head gasket; FIG. 5 is a partial cross-sectional perspective view of the cylinder head gasket; FIG.
-V line sectional view, Figure 6 is a Vl-VT line sectional view in Figure 3,
FIG. 7 is a sectional view taken along the line ■--■ in FIG. 3. 0a...opening end, 11...combustion chamber hole. 2...Cooling water hole, 13...Lubricating oil hole. 4...Bolt hole, 15...Bead. 0... Shim ring. 1... Seal member for combustion chamber hole. 2... Seal member for cooling water hole

Claims (2)

[Claims] (1) In a cylinder head gasket in which at least a combustion chamber hole through which combustion gas passes and a cooling water hole through which cooling water passes are bored in a metal substrate, a sealing member is provided around the cooling water hole; A cylinder head gasket characterized in that the thickness of the sealing member on the combustion chamber hole side is greater than the thickness on the opposite side. (2) In a cylinder head gasket in which a plurality of combustion chamber holes through which at least combustion gas passes and a plurality of cooling water holes through which cooling water passes are bored in a metal substrate, at least one of the plurality of cooling water holes is formed. A cylinder head gasket characterized in that a sealing member is provided so as to surround some of the cooling water holes in a continuous line.