JPH03121376A - Metal gasket - Google Patents

Abstract

PURPOSE:To obtain a metal gasket having no warp by forming a turn-down portion of a sub-plate, keeping the form of a warp in the bead projecting direction between the combustion chamber hole side edge of a base plate and a bead forming portion, which is produced by the residual stress at the time of forming a bead. CONSTITUTION:A turn-down portion 16a of a sub-plate 16 is formed, keeping the form of a warp in the bead projecting direction of a non-bead forming portion 14b of a base plate 14, which is produced by the residual stress at the time of forming a bead. The non-bead forming portion 14b of the base plate 14 is superposed on the turn-down portion 16a of the sub-plate 16 without deformation of the warp form. Accordingly, at the time of bending the end of the sub-plate 16 to be superposed on the non-bead forming portion 14b of the combustion chamber hole side edge of the base plate 14, no reaction force is produced in the non-bead forming portion 14b of the base plate 14, and there is no warp in the manufactured metal gasket itself.

Description

Detailed Description of the Invention [Industrial Application Field 1] The present invention relates to a metal gasket having a bead formed thereon to seal the joint surface between a cylinder head and a cylinder block of an internal combustion engine, particularly on the combustion chamber hole side. The present invention relates to a metal gasket in which an overlapping portion is formed.

[Prior Art 1] A force that expands and contracts the deck surface gap around the combustion chamber acts on the joint surface between the cylinder head and cylinder block of an internal combustion engine due to the combustion gas pressure during combustion. For this reason, conventionally, the cylinder head and cylinder block are bolted together via a metal gasket with a bead formed on the joint surface.
Efforts have been made to improve the sealing performance of the joint surface between the cylinder head and the cylinder block.

However, when the cylinder head and cylinder block are bolted together via a metal gasket as described above, the bolt tightening force causes the cylinder head to curve and cause distortion around the combustion chamber, causing combustion gas to leak from that location. Also, due to the alternating loads during combustion, the bead of the metal gasket may become sagging, resulting in disadvantages such as reducing the sealing effect of the metal gasket.

As an example of a metal gasket made in order to eliminate such inconveniences, a metal gasket described in Japanese Patent Application No. 60-29282 is shown in FIG. Illustrated metal gasket 1
2, a sub-plate 16 is laminated on the substrate 14 on which the bead 14a is formed, and the sub-plate is stacked on the non-bead formed part 14 of the edge of the substrate 14.
Overlapping part 18 that is folded back to the b side and is thicker than other laminated parts
The overlapping portion compensates for the gap around the combustion chamber that occurs when the cylinder head and cylinder block are bolted together.

[Problems to be Solved by the Invention] However, metal gas scalers 1 to 1 in which a sub-plate is superimposed on a substrate on which beads are formed as described above and the sub-plate is folded back toward the substrate at the edge of the substrate, As shown by reference numeral 12 in the drawings and FIG. 4, there is a disadvantage that the finished state is not flat and the metal gasket itself is warped.

The cause of warping of metal gaskets is the seventh
This is due to the manufacturing method of the metal gasket 12 shown in Figs. Form. Due to the residual stress generated during this bead forming, the non-bead formed portion 14 at the edge of the substrate 14
b is the inclination angle α with respect to the horizontal plane 15 in the bead protrusion direction.
A warpage having a value of `` occurs. Next, a sub-plate 16 having a folded portion 16a formed in a substantially vertical direction as shown in FIG. 7(ial) is attached to the warped substrate 14 as shown in FIG.
) as shown in FIG. The mold 21 is pressed in the direction of the mold 21 according to the arrows, facing the mold 22 having a pressing surface. At this time, the folded portion 6a of the sub-plate 16 is folded back toward the non-bead formed portion 14b side of the substrate 14, and the folded portion 16 shown in FIG.
By the flat pressing process for close contact polymerization in a, the non-bead molded portion 14b of the substrate 14 is deformed so as to be forcibly warped along the direction of the flat pressing surface of the mold 21. However, in the metal gasket created in this way, the non-bead formed portion 1 of the substrate 14 is formed when the flat pressing process is completed.
4b tries to restore itself again due to the reaction force at the time of deformation, causing the metal gasket 12 itself to warp.

When this warped metal gasket 12 is interposed between the joint surface of the cylinder head (not shown) of the internal combustion engine 52 and the cylinder block 54, the cylinder 59 as shown in FIG.
When the metal gasket 12 is mounted with the warp facing upward on a deck surface with positioning pins 58 provided on both sides in the arrangement direction, the positioning holes 56 are fitted with the positioning pins 58 as shown in FIG. positioning. However, if the metal gasket 12 is inserted with its warp facing downward with respect to the deck surface as shown in FIG. 5, the positioning hole 56 cannot be fitted into the positioning pin 58 as shown in FIG. , metal gasket 12
There was a problem that positioning could not be performed reliably.

When installing a warped metal gasket between the joint surfaces of the cylinder head and cylinder block, it may not be possible to position it reliably depending on the orientation of the metal gasket, resulting in the problem that the assembly line cannot run smoothly. was there.

Therefore, the present invention prevents warping of the metal gasket during bead forming, and makes it possible to position the metal gasket by reliably interposing it between the joining surfaces of the cylinder head and the cylinder block, regardless of the direction of orientation of the metal gasket. The purpose is to provide metal gaskets.

[Means for Solving the Problems 1] The above problems are solved by providing a sub-plate laminated on at least one side of a substrate made of an elastic metal plate on which beads surrounding a combustion chamber are formed. In a metal gasket in which a folded portion is formed by folding and overlapping the combustion chamber hole side edge of the sub-plate to the combustion chamber hole side edge of the substrate, the combustion chamber hole side edge of the substrate generated due to residual stress during the bead forming. This problem can be solved by a metal gasket characterized in that the folded portion of the secondary plate is formed so that the warpage in the bead protrusion direction between the bead forming portion and the bead forming portion is substantially unchanged.

[Effect 1: When forming a bead on the board by pressing a mold against the bead forming part, warping occurs from the bead forming part of the board to the non-bead forming part of the edge of the board on the side of the combustion chamber hole. .

In the metal gasket of the present invention, the folded portion of the sub-plate is formed by keeping the warpage of the non-bead-formed portion of the substrate in the bead protrusion direction substantially unchanged due to residual stress during bead-forming. , the non-bead formed portion of the substrate is superimposed on the folded portion of the sub-plate without changing the shape of the warp.

Therefore, when the edge of the sub-plate is bent and superimposed on the bead-formed part of the edge of the combustion chamber hole Ill of the board, no reaction force is generated in the non-bead-formed part of the board, and the metal gasket is produced. It does not cause warping itself.

[Embodiment 1] Hereinafter, embodiments of the present invention will be described with reference to the drawings.

FIG. 1 (al to fe) shows a method of manufacturing the metal gasket of this example. However, Fig. 7 fat~iel
The same reference numerals are used for the same parts.

On the substrate 14 shown in FIG. 1 (bl), a bead 14a as shown in the figure is formed by pressing a mold (not shown) on the original plate in advance.As shown in the figure, the residual stress generated during bead forming , a warpage having an inclination angle α with respect to the horizontal plane 15 occurs from the bead-formed portion of the substrate 14 toward the non-bead-formed portion 14b at the edge of the substrate.

Next, the substrate 14 having such a warp is subjected to a process as shown in FIG.
FIG. 1 shows a sub-plate 16 in which a folded part 16a is formed in a substantially vertical direction as shown in FIG. As shown in (c), the non-bead forming part 1
4b and the inclined part 16b overlap, and then the first
As shown in FIG.
An inclined pressing surface 23a) having approximately the same inclination angle α as 6b, and an otherwise flat upper die 23 are provided on the back side, and from the opposite direction, the folded portion 16a is formed into a curved pressing surface 22 having a radius R.
It is pressed in the direction of the upper mold 23 while facing the lower mold 22 having the shape a. At this time, the folded portion 16a of the sub-plate 16 is folded back toward the non-bead-formed portion 14b of the substrate 14, but the non-bead-formed portion 14b of the substrate 14 is inserted into the inclined portion of the upper mold 23 through the inclined portion 16b of the sub-plate 16. Since the non-bead forming portion 14b of the substrate 14 is in contact with the shaped pressing surface 23a, the folded portion 16a of the sub-plate 16 is attached to the non-bead forming portion 14b through the flat pressing process shown in FIG. 1(e) without being deformed. Polymerized. Thus, substrate 1
No reaction force is generated in the non-bead molded portion 14b of No. 4, and no warping occurs in the metal gasket 10 itself taken out from the upper and lower molds 22 and 23.

Note that the pressing step shown in FIG. 1 (el) can be carried out using the mold shown in FIGS. 8 and 9. The mold shown in FIG. An upper mold 23 having an inclined pressing surface 23a formed at an angle, a lower curling mold 22 having a curved pressing surface 22a having a radius R, and a lower bead mold 2 having a bead receiving surface 24a.
It consists of 4. A spring spring 26 is interposed between the bead part side lower mold 24 and the base 27, and the bead part side lower mold 24
The pressing surface of is provided to protrude from that of the lower curling mold 22 due to the interposition of this spring 26.

Therefore, when the base 27 is raised toward the upper mold 23 side.

The bead receiving surface 24a and other flat parts of the lower mold 24 on the bead side come into contact with the bead part 14a of the substrate 14 and the flat plate part thereof, but as the base 27 rises, they resist the spring 26. From the time when the bead part side lower die 24 descends and the curved pressing surface 22a of the curling side lower die 22 comes into contact with the folded part 16a of the secondary plate 16, the folded part 16a
are gradually folded back and overlapped toward the non-bead forming portion 14b side of the substrate 14. Note that 25 is a buffer member made of, for example, rubber or sponge, which is attached on the bead receiving surface 24a.

In this mold as well, as in the above mold, the non-bead forming part 14b of the base i14 is in contact with the inclined pressing surface 23a of the upper mold 23 via the inclined part 16b of the sub-plate 16.
The non-bead molded portion 14b of No. 4 is attached to the sub-plate 16 without being deformed.
The folding part! , 6a are folded and polymerized, so no reaction force is generated on the substrate 14, so the metal gasket l
O itself does not warp. Note that, according to this mold, when the folded portion 16a of the sub-plate 16 is folded back, the substrate 14 has already been folded.
Since the bead forming portion 14b and other flat plate portions are pressed against the bead portion side lower mold 24 against the elastic force of the spring 26, the substrate 14 is It does not warp (recurve),
The entire substrate 14 can be held under pressure with a substantially uniform pressing force.

Further, the mold shown in FIG. 9 has an inclined pressing surface 28a formed on the upper mold 28 at approximately the same angle as the inclined portion 16b of the sub-plate 16,
The lower mold 29 facing this has an inclined suppressing surface 29a that is inclined similarly to the above-mentioned inclined suppressing surface 28a, and the non-bead molded portion 1 of the substrate 14 is provided between the upper and lower inclined suppressing surfaces 28a and 29a.
b and the inclined part 16b of the sub-plate 16, and the upper mold 28
By suppressing and holding between the mold 29 and the lower mold 29, the folded part 16a of the sub-plate 16 can be overlapped without deforming the non-bead molded part 14b of the substrate 14, as with the mold described above,
The metal gasket 10 itself does not warp.

In addition, in the said Example, it is for convenience of explanation.

A substrate 14 and a sub-plate 16 are used to create the metal gasket 10.
Although the illustration shows that a stack of the substrate 14 and the sub-plate 16 is pressed against the lower mold while in contact with the upper mold 23 or 28 side, the stack of the substrate 14 and the sub-plate 16 is placed on the lower mold. Suppression is performed while the positioning pin is placed in the position and positioned with the positioning pin.

Moreover, the non-bead molded portion 14 of the substrate 14 is preliminarily formed on the sub-plate 16.
It is designed to overlap the non-bead formed portion 14b of the substrate 14 with the inclined portion 16b having approximately the same angle as the inclined angle α of the sub-plate 16.
It is also possible to form a slope similar to that of the slope part 16b by pressing the slope pressing surface 23a or 28a of the upper mold during pressing, and overlap it with the non-bead molded part 14b of the substrate 14, with only part a formed. good.

[Effect of the invention 1] As explained above, according to the present invention, the bead protrusion between the edge of the combustion chamber hole side of the substrate and the bead formed portion (non-bead formed portion) caused by residual stress during bead forming is reduced. Since the folded part of the sub plate is formed with the warpage in the direction almost unchanged, no reaction force is generated in the non-bead formed part during this folding process, and therefore, the metal is made without warping. You can get a gasket.

When installing such a metal gasket on the joint surface between the cylinder head and cylinder block, it can be oriented in the desired direction and positioned accurately, which is also beneficial for smooth operation of the assembly line. .

[Brief explanation of drawings]

FIGS. 1 fa) to fel are schematic cross-sectional views showing a method of manufacturing a metal gasket according to an embodiment of the present invention. Second
The figure is a cross-sectional view of a conventional metal gasket. 3 to 6 are perspective views or side views for explaining the drawbacks of conventional metal gaskets. Figure 7 (at~te
1 is a schematic cross-sectional view illustrating a conventional method of manufacturing a metal gasket. FIG. 8 and FIG. 9 are schematic cross-sectional views showing a mold as another embodiment of the present invention. 10...Metal gasket 14...Substrate 14a...Bead forming part 14b...Non-bead forming part 16...Subplate 16a...Folded part 16b...Slanted part 22.28... Lower mold 23, 29... Upper mold 22a... Curved suppression surfaces 23a, 28a of the lower mold... Inclined pressing surface 29a of the upper mold...
Slanted suppressing surface 0 of lower mold...metal gasket 4...substrate 4a, bead forming part 4b...non-bead forming part 6, sub-plate 6a...delayed part 6b...1' Around, Ll part 2.28...lower die 3.2...upper die 2a...curved pressing surface 3a, 28a of lower die...slanted pressing surface 9a of upper die...lower die The inclined pressing surface of Fig. 4a Mouth ■

Claims (1)

[Claims] A sub-plate is laminated on at least one side of a substrate made of an elastic metal plate formed with a bead surrounding the combustion chamber, and an edge of the sub-plate on the combustion chamber hole side is folded back to an edge of the substrate on the combustion chamber hole side. In a metal gasket in which a folded portion is formed by polymerization, the warpage in the bead protrusion direction between the edge of the combustion chamber hole side of the substrate and the bead formed portion, which is caused by residual stress during the bead forming, is maintained almost as is. A metal gasket characterized in that the sub-plate is shaped to form a folded portion.