JPH08121597A - Metal gasket - Google Patents

Abstract

PURPOSE: To heighten tightening pressure of a cylinder opening edge part to the maximum and to display a sufficient sealing property by abuttedly polymerizing a ridge of a full bead of each main plate with a folded part of an auxiliary plate as well as sandwiching the auxiliary plate with two pieces of the main plates. CONSTITUTION: A main plate 1 is formed in a specified shape having openings of a cylinder opening 5, a bolt hole, a cooling water opening, a lubricating oil opening, a chamber, etc., and a full bead 11 is provided on a peripheral edge part of the cylinder opening 5 on a metal gasket for a cylinder head consisting of two pieces of the main plates which are comparatively thick and one piece of the auxiliary plate 2 which is comparatively thin. Thereafter, the auxiliary plate 2 is formed in a specified shape having the openings except for the cylinder opening 5, an outer edge 2b of a folded part 2a is positioned on the outside of the central line CL of the full bead 11 by folding the peripheral edge part of the cylinder opening of the auxiliary plate 2, this auxiliary plate 2 is sandwiched by two pieces of the main plates 1, and a mound 11a of the full bead 11 is abuttedly polymerized with the folded part 2a.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a metal gasket for a cylinder head of an internal combustion engine.

[0002]

2. Description of the Related Art FIGS. 3 to 5 show a conventional metal gasket, in which 1 is a main plate made of a relatively thick metal plate, and 2 is a relatively thin plate. Metal plate 3,4
Is a metal gasket for a cylinder head formed by sandwiching the secondary plate 2 between two main plates 1 and 1, and 5 is a cylinder port, 6 is a bolt hole, and 7 is a cooling water port. , 8 is a lubricating oil port, 9 is a chamber, 1
0 is a caulking hole.

Reference numeral 11 denotes a circular full bead formed on the peripheral portion of each cylinder port 5 of the main plate 1, 12 denotes a half bead formed on the main plate 1 so as to enclose each cooling water port 7,
Reference numeral 3 is a half bead formed on the main plate 1 so as to enclose each lubricating oil port 8, and 14 is a half bead formed on the main plate 1 so as to enclose the chamber 9. Further, 3a (see FIG. 4) is a wide folded portion in which the cylinder edge portion of one metal plate 3 of the sub plate 2 is folded back, and the other metal plate 4 is sandwiched, and 3b (see FIG. 5). (Refer to) is a folded portion that is also narrow.

[0004]

Since the conventional metal gasket as described above is composed of the two main plates 1 and the sub plate 2 obtained by superimposing the two metal plates 3 and 4, the number of laminated layers is relatively large. Therefore, the thickness of the gasket is large, the amount of steel used increases, and the heat conduction becomes poor.
There was a problem that a heat spot was formed on the refraction part 3c and the crack was easily generated. Especially as shown in FIG.
When the width of the folded portion 3b is narrow and the peak of the full bead 11 is off the folded portion 3b, this folded portion 3b
There is a problem that the restoring force of the full bead 11 on the side cannot be obtained sufficiently.

[0005]

In order to solve the above-mentioned problems, in the present invention, two main plates having a relatively large thickness and a thickness interposed between these two main plates are relatively large. In a metal gasket for a cylinder head, which is composed of one thin auxiliary plate, the main plate is formed into a predetermined shape having openings such as a cylinder port, a bolt hole, a cooling water port, a lubricating oil port, and a chamber. A full bead is provided on the peripheral edge, and the sub-plate is formed into a predetermined shape having openings other than the cylinder port, and the cylinder plate peripheral part of the sub-plate is folded back so that the outer edge of this folded-back part is closer to the center line of the full bead. The auxiliary plate is positioned outside, and the auxiliary plate is sandwiched between the two main plates, and the peaks of the full beads of each of the main plates are polymerized so as to abut the folded-back portion of the auxiliary plate, and the metal gasket Constitute a.

[0006]

The function of the metal gasket of the present invention is as described above.
Since one auxiliary plate is sandwiched between two main plates, the number of laminated plates is smaller and the amount of steel used is reduced as compared with the conventional metal gasket in which laminated auxiliary plates are inserted between the main plates. The overall thickness is also reduced. In addition, the cylinder edge of the sub plate is formed by folding back the sub plate directly to form a wide folded portion, and the crest of the full bead formed on the main plate abuts against this folded portion. The tightening pressure of the part becomes the highest, and sufficient sealing performance can be exhibited. In addition, because the thickness of the gasket as a whole is small, heat conduction is better than that of conventional thick gaskets.
In particular, when folded back, it is difficult to form a heat spot on the bent portion, and therefore, the risk of cracking is reduced.

[0007]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to FIGS. In the figure, the same symbols as the above-mentioned symbols indicate the same items. That is, in the figure, 1 is a main plate made of a metal plate having a relatively large thickness, 2 is a sub plate having a relatively thin thickness, and G sandwiches the sub plate 2 between two main plates 1 and 1 in a sandwich shape. The metal gasket for a cylinder head formed in step 5 is a cylinder port, 6 is a bolt hole, 7 is a cooling water port, 8 is a lubricating oil port, 9 is a chamber, and 10 is a caulking hole.

Reference numeral 11 denotes a circular full bead formed on the peripheral portion of each cylinder port 5 of the main plate 1, 12 denotes a half bead formed on the main plate 1 so as to enclose each cooling water port 7,
3 is a half bead formed on the main plate 1 so as to enclose each lubricating oil port 8, and 14 is a half bead formed on the main plate 1 so as to enclose the chamber 9.

In this embodiment, there are two main plates 1 having a relatively large thickness and one auxiliary plate 2 having a relatively small thickness interposed between the two main plates 1. In a metal gasket for a cylinder head, the main plate 1 is formed into a predetermined shape having openings such as a cylinder port 5, a bolt hole 6, a cooling water port 7, a lubricating oil port 8 and a chamber 9, and at the periphery of the cylinder port 5. With a full bead 11,
The sub-plate 2 is formed into a predetermined shape having openings other than the cylinder port 5, and the peripheral edge of the cylinder port of the sub-plate 2 is folded back so that the outer edge 2b of the folded-back part 2a is closer to the center line CL of the full bead 11. So that it ’s located outside,
The sub-plate 2 is sandwiched between the two main plates 1, and the peaks 11a (see FIG. 2) of the full beads 11 of each main plate 1 are sub-plates 2.
The metal gasket G is formed by superimposing the metal gasket G so as to collide with the folded-back portion 2a.

[0010]

Since the metal gasket G of the present invention sandwiches one sub-plate 2 between the two main plates 1 and 1 as described above, a conventional laminated sub-plate is inserted between the main plates. Compared with a metal gasket, the number of laminated layers is smaller, the amount of steel used is reduced, and the thickness of the entire gasket is reduced. The cylinder edge of the sub-plate 2 is formed by directly folding the sub-plate 2 to form a wide folded portion 2a, and the crest 11a of the full bead 11 formed on the main plate 1 is formed on the folded portion 2a.
Since they are abutted against each other, the tightening pressure at the rim of the cylinder is maximized, and sufficient sealing performance can be achieved.

As described above, according to the present invention, a shim step type metal gasket can be manufactured at low cost. In addition, the plate thickness of the used steel plate (for example, stainless steel plate) is, for example,
By arbitrarily selecting within the range of 0.25 to 0.05 mm, it becomes possible to finely adjust the step of the shim.

Further, the metal gasket G of the present invention has better heat conduction than the conventional thick gasket since the thickness of the entire gasket is small, and especially the bent portion 2c when folded back.
(See FIG. 2) It is difficult to form a heat spot, and therefore, there is an effect that the risk of cracking is reduced.

[Brief description of drawings]

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

FIG. 2 is an enlarged cross-sectional view taken along the line AA of FIG.

FIG. 3 is a plan view showing an example of a conventional metal gasket.

FIG. 4 is an enlarged sectional view taken along line BB of FIG.

5 is an enlarged plan view showing a modified example of FIG.

[Explanation of symbols]

 1 Main Plate 2 Sub Plate 2a Folded Part 2b Outer Edge 2c Bent Part 3 Metal Plate 3a Wide Folded Part 3b Narrow Folded Part 3c Bent Part 4 Metal Plate G Metal Gasket 5 Cylinder Port 6 Bolt Hole 7 Cooling Water Port 8 Lubrication Oil port 9 Chamber 10 Caulking hole 11 Full bead 11a Full bead mountain CL Center line 12, 13, 14 Half bead

Claims (1)

[Claims] 1. A metal gasket for a cylinder head comprising two main plates having a relatively large thickness and one auxiliary plate having a relatively small thickness interposed between the two main plates, The main plate is formed into a predetermined shape with openings such as a cylinder port, bolt hole, cooling water port, lubricating oil port, and chamber, and a full bead is provided at the peripheral edge of the cylinder port, and the sub plate is the other opening except the cylinder port. And the peripheral edge of the cylinder of the secondary plate is folded back so that the outer edge of the folded back portion is located outside the center line of the full bead.
A metal gasket, which is sandwiched between a plurality of main plates, and is piled up so that the peaks of the full beads of each main plate collide with the folded portions of the sub plates.