JP3994347B2 - Cylinder head gasket manufacturing method - Google Patents

Description

  The present invention relates to a method for manufacturing a cylinder head gasket, and more particularly to a method for manufacturing a cylinder head gasket including a gasket substrate and a shim ring.

Conventionally, a cylinder head gasket is sandwiched between a cylinder head and a cylinder block of an engine, and a combustion chamber hole is formed in the cylinder head gasket in accordance with the position of the cylinder bore.
As such a cylinder head gasket, one having a substrate provided with combustion chamber holes and a shim ring provided around the combustion chamber holes and fixed to the substrate is known. What has prevented exhaust leakage from the air is known. (Patent Document 1)
In order to manufacture the cylinder head gasket of Patent Document 1, first, the substrate and the shim ring are polymerized, and in this state, the substrate and the shim ring are welded to each other. Finally, the substrate and the shim ring are placed at the position of the combustion chamber hole. It cuts together.
Further, as a cylinder head gasket having another configuration, it is known to have three substrates, upper, middle, and lower, of which an intermediate plate located in the middle is formed with a bent portion in accordance with the position of the combustion chamber hole. Yes. (Patent Document 2: Especially the configuration of FIG. 11)
According to the cylinder head gasket of Patent Document 2, exhaust gas leakage from the cylinder bore is prevented by the bent portion, and the bent portion can be manufactured by a conventionally known hemming process or the like. Yes.
JP-A-4-296256 JP-A-8-291863

However, in the method of manufacturing a cylinder head gasket according to Patent Document 1, it is necessary to manufacture a shim ring separately from the substrate. However, since the shim ring has a ring shape, there is a problem that the yield is poor.
Further, when the substrate and the shim ring are welded, the substrate and the shim ring must be positioned, and there has been a problem that a positioning process, a positioning jig, and the like must be separately prepared.
On the other hand, when the intermediate plate described in Patent Document 2 is manufactured, it is only necessary to perform hemming, so it is not necessary to perform welding or positioning as in Patent Document 1, but the bent portion includes Since a strong spring force exists, the surface pressure is concentrated at the position of the bent portion, and indentation may occur in the cylinder block or the cylinder head.
In view of such problems, the present invention provides a method of manufacturing a cylinder head gasket that can obtain a cylinder head gasket having a gasket substrate and a shim ring that is less likely to cause the above-mentioned indentation at a lower cost than conventional ones. To do.

That is, the method of manufacturing a cylinder head gasket according to the present invention includes a gasket substrate sandwiched between a cylinder head and a cylinder block and having a combustion chamber hole formed at a cylinder bore, and surrounding the combustion chamber hole. A method of manufacturing a cylinder head gasket comprising a shim ring fixed to
A through-hole having a smaller diameter than the combustion chamber hole is formed in the plate-shaped gasket material, and the peripheral portion of the through-hole is folded outward in the radial direction. When the gasket material is superposed on the gasket material while the gasket material and the polymerized peripheral portion are fixed to each other, the folded portion is removed at the position of the combustion chamber hole and the peripheral portion is removed. Is a shim ring.

Since the cylinder head gasket obtained by the above manufacturing method does not have a bent portion around the cylinder bore as in the above-mentioned Patent Document 2, there is no possibility that indentation will occur in the cylinder head or cylinder block.
In addition, since the gasket substrate and shim ring can be obtained from a single gasket material, there is no need to manufacture the shim ring separately, and there is no need to perform positioning for welding. Can also be manufactured at low cost.

The illustrated embodiment will be described below. FIG. 1 shows a cylinder head gasket 1, which is sandwiched between a cylinder head (not shown) and a cylinder block to seal between them.
As shown in FIG. 1, the cylinder head gasket 1 is provided with a plurality of combustion chamber holes 2 formed in accordance with the cylinder bores of the cylinder block, a plurality of bolt holes 3 for inserting fastening bolts (not shown), and lubricating oil. An oil hole 4 to be circulated and a water hole 5 to circulate cooling water are formed.
2 shows a cross section taken along line II-II in FIG. 1. The cylinder head gasket 1 includes three metal first to third gasket substrates 11 to 13, and a first gasket substrate located in the center. A shim ring 14 that surrounds the combustion chamber hole 2 is provided between the first gasket substrate 12 and the second gasket substrate 12 positioned thereabove.
The first gasket substrate 11 is formed by drilling the combustion chamber hole 2 and the bolt hole 3 in a flat gasket material, and the first gasket substrate 11 is provided with the second gasket substrate 12 and a third gasket provided below. It is sandwiched between gasket substrates 13.
The surfaces of the second gasket substrate 12 and the third gasket substrate 13 are each coated with a coating made of rubber, resin or the like, and each substrate surrounds the combustion chamber hole 2 in an endless manner. Full beads 12A and 13A projecting toward the substrate 11 are formed.
The shim ring 14 is made of the same material as the first gasket substrate 11, surrounds the periphery of the combustion chamber hole 2 with a substantially constant width, and is disposed closer to the combustion chamber hole 2 than the full beads 12A, 13A. It is fixed to the upper surface of the gasket substrate 11 by welding.
Here, the shim ring 14 is welded to the first gasket substrate 11 in order to prevent the shim ring 14 from shifting with respect to the cylinder bore, and the coating in which the second and third gasket substrates 12 and 13 are made of rubber, resin, or the like. This is because it is covered by and cannot be welded.

According to the cylinder head gasket 1 having such a configuration, exhaust leakage and the like from the cylinder bore can be satisfactorily prevented by the full beads 12A and 13A and the shim ring 14.
Further, by providing the shim ring 14, the pressure acting on the full beads 12A and 13A can be dispersed when the cylinder head gasket 1 is sandwiched between the cylinder block and the cylinder head, and the durability of the cylinder head gasket 1 is improved. Can be improved.

Next, a method for manufacturing the cylinder head gasket 1 will be described. Here, since the manufacturing method of the second and third gasket substrates 12 and 13 is not different from a conventionally known manufacturing method, the description thereof will be omitted, and the manufacturing method of the first gasket substrate 11 and the shim ring 14 will be described.
FIGS. 3A to 3D show a method for manufacturing the first gasket substrate 11 and the shim ring 14, and show the manufacturing process for the position of the II-II cross section of FIG. A two-dot chain line in the figure indicates the position of the combustion chamber hole 2.
First, FIG. 3A shows the gasket material 15 to be the first gasket substrate 11 and the shim ring 14, and a through hole 15 a having a smaller diameter than the combustion chamber hole 2 is formed at the position to become the combustion chamber hole 2. The process to set is shown.
The center of the through hole 15a is provided so as to coincide with the center of the combustion chamber hole 2, and its diameter is determined by the width of the shim ring 14 and the range of the folded portion 15c described below. Also, the bolt hole 3, the oil hole 4 and the water hole 5 can be formed simultaneously with the through hole 15a.

The process shown in FIG. 3B is a process in which the peripheral edge 15b of the through hole 15a is turned back outward in the radial direction by a conventionally known hemming process.
Specifically, first, the peripheral edge 15b having a predetermined width is pushed upward from the through hole 15a, and then the peripheral edge 15b is folded back so as to protrude to the outer peripheral side from the combustion chamber hole 2, and then the peripheral edge 15b. And the gasket material 15 positioned therebelow are polymerized.
At this time, the folded portion 15c formed by the hemming process is positioned on the inner peripheral side with respect to the combustion chamber hole 2, and on the outer peripheral side with respect to the combustion chamber hole 2, the peripheral portion 15b, the gasket material 15, and Are both flat.
Here, the distance from the position of the combustion chamber hole 2 to the end of the peripheral edge portion 15b is set to be the same as the width of the shim ring 14, and the distance from the position of the combustion chamber hole 2 to the turning portion 15c is turned back. The portion having the curvature of the portion 15 c is set so as not to be positioned on the outer peripheral side of the combustion chamber hole 2.

The step shown in FIG. 3C is a step of welding the peripheral edge portion 15b and the gasket material 15 to each other. In this embodiment, conventionally known laser welding is employed for welding.
In the present embodiment, the peripheral portion 15b and the gasket material 15 may not be in close contact with each other only by performing the above-described hemming process, so that the peripheral portion 15b is pressed against the gasket material 15 from above using the pressing member 16. It has become.
From the state in which the peripheral edge portion 15 b is pressed by the pressing member 16 in this way, the position that is the outer periphery from the combustion chamber hole 2 is welded endlessly using a conventionally known laser welding means 17.
At this time, welding can be intermittent, and other welding methods can be used besides the laser welding means 17. For example, when using resistance welding means, welding can be performed while pressing the peripheral edge portion 15b against the gasket material 15 by means of electrodes, so that the pressing member 16 becomes unnecessary.

Finally, the step shown in FIG. 3D shows a step of removing the folded portion 15 c at the position of the combustion chamber hole 2.
The folded portion 15c is removed by shearing, and by removing the folded portion 15c, the gasket material 15 located on the outer peripheral side of the combustion chamber hole 2 becomes the first gasket substrate 11, and the peripheral portion 15b becomes the shim ring 14. The first gasket substrate 11 and the shim ring 14 can be obtained from one gasket material 15.

By using the first gasket substrate 11 and the shim ring 14 thus manufactured for the cylinder head gasket 1, the following effects can be obtained.
First, since the folded portion 15c is removed in the step of FIG. 3D, when the cylinder head gasket 1 is sandwiched between the cylinder block and the cylinder head, the folded portion 15c causes the cylinder block and the cylinder head to be indented. Will not occur.
Further, since the first gasket substrate 11 and the shim ring 14 can be obtained from the one gasket material 15, it is not necessary to prepare the first gasket substrate 11 and the shim ring 14 separately as in the prior art, and the material cost is reduced. Can be reduced.
In particular, since the shim ring 14 has a narrow ring shape surrounding the combustion chamber hole 2, it is very expensive to manufacture this separately from the first gasket substrate 11 in terms of yield. It was.
Moreover, since the said folding | returning part 15c is removed after welding the peripheral part 15b and the gasket raw material 15, it is not necessary to position a shim ring and a board | substrate like patent document 1, and the jig | tool for positioning and its process The manufacturing cost can be reduced by shortening the manufacturing time.

In this embodiment, since the resin coating is applied to the second and third gasket substrates 12 and 13, the shim ring 14 could not be welded to the second and third gasket substrates 12 and 13, When coating is unnecessary, either the second gasket substrate 12 or the third gasket substrate 13 can be used as the first gasket substrate 11, and the above manufacturing method can be applied to the first gasket substrate 11.
At this time, the shim ring 14 may be welded to the lower surface of the first gasket substrate 11. In this case, in the above manufacturing method, only the hemming direction is set to the lower side.
As described above, the present invention is not limited to the manufacturing method of the cylinder head gasket 1 including the three gasket substrates as in the above-described embodiment, and has a configuration in which the gasket substrate and the shim ring 14 are welded to each other. Any cylinder head gasket 1 is applicable.

The top view which shows the cylinder head gasket in a present Example. Sectional drawing which shows the II-II part in FIG. It is a figure which shows the manufacturing method of a 1st gasket board | substrate, Comprising: The schematic process drawing which showed the manufacturing method about the same part as the said FIG.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Cylinder head gasket 2 Combustion chamber hole 11-13 The 1st-3rd gasket board | substrate 14 Shim ring 15 Gasket material 15a Through-hole 15b Peripheral part 15c Folding part

Claims (3)

A cylinder head gasket comprising: a gasket substrate sandwiched between a cylinder head and a cylinder block and having a combustion chamber hole formed at a cylinder bore; and a shim ring surrounding the combustion chamber hole and fixed to the gasket substrate. A manufacturing method comprising:
A through-hole having a smaller diameter than the combustion chamber hole is formed in the plate-shaped gasket material, and the peripheral portion of the through-hole is folded outward in the radial direction. When the gasket material is superposed on the gasket material while the gasket material and the polymerized peripheral portion are fixed to each other, the folded portion is removed at the position of the combustion chamber hole and the peripheral portion is removed. A method of manufacturing a cylinder head gasket, characterized in that a shim ring is used.   The cylinder head gasket includes at least a first gasket substrate and a second gasket substrate that are superposed on each other, the shim ring is provided on the second gasket substrate side of the first gasket substrate, and the second gasket substrate 2. A bore bead surrounding the combustion chamber hole and projecting toward the first gasket substrate is formed, and the shim ring is arranged to be located closer to the combustion chamber hole than the bore bead. The manufacturing method of the cylinder head gasket of description.   A third gasket substrate is superposed on the opposite side of the second gasket substrate to the first gasket substrate, and a bore bead surrounding the combustion chamber hole and projecting toward the first gasket substrate is formed on the third gasket substrate. 3. The method of manufacturing a cylinder head gasket according to claim 2, wherein the shim ring is formed and disposed so as to be positioned closer to the combustion chamber hole than the bore bead.

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