JP2000097340A - Metal cylinder head gasket with interbore slit - Google Patents

Abstract

PROBLEM TO BE SOLVED: To secure a prescribed sealing performance by a small clamping axial force by providing a slit between beads in a gasket having the beads arranged in such a state as adjoiningly surrounding adjoining bores between them. SOLUTION: Beads 2 are arranged in such a state as adjoiningly surrounding adjoining bores 1 between them and a slit 3 is provided in a position P between them. The slit 3 which is a continuos groove is provided with circular holes 4 of a diameter larger than the width W in its both ends, the longitudinal length and the width W of the slit 3 are appropriately selected from the interval of the bores 1, the interval and the dimension and shapes of the beads 2, the clamping axial force, a surface pressure, etc., and a deformation absorbing space sufficient for the bead 2 smoothly exhibiting a prescribed spring performance in mounting can be secured. The bead 2 can thus secure the sealing performance by a prescribed clamping axial force, and avoid the crack from initiated in the beads by the increase in the loading stress and impression from generated in the contact face between the cylinder head and a block by the excessive surface pressure.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a cylinder head gasket for an engine, and more particularly to a metal cylinder head gasket for use in an automobile engine having a relatively small gap between bores.

[0002]

2. Description of the Related Art In recent years, it has been required that a cylinder head gasket of an automobile engine can be sealed with a thinner thickness against a higher internal pressure.
Metal gaskets with beads around the bore are often used. This type of metal cylinder head gasket performs a seal around the bore due to the bead spring characteristics. Further, in such a metal cylinder head gasket, the bead of each bore is formed integrally with one bead between the mutually adjacent bores. However, because the distance between adjacent bores is relatively small, the bead cannot be made with a sufficiently large size and shape, resulting in insufficient spring characteristics, causing seal leakage, and heat concentration during engine operation. As a result, the temperature between the bores becomes high, causing the beads to settle, making it difficult to ensure the sealing performance.

[0003] In order to solve such a lack of sealing performance due to the beads, a metal cylinder head gasket is provided between adjacent bores without being integrated with the beads of the respective bores and independently arranged in an independent shape. Has been proposed.

[0004]

However, in this type of metal cylinder head gasket, the bead width is reduced due to the relatively small space between the bores, the compression resistance of the bead becomes too high, and the metal cylinder head gasket is mounted on an engine. In some cases, the beads cannot be sufficiently compressed even if the beads are mounted with a predetermined tightening axial force, and sufficient sealing properties cannot be secured.
In addition, when a tightening axial force is applied, the load stress generated in the bead becomes too high, and not only has a disadvantage that a crack is easily generated in the bead, but also a high surface pressure generated in the bead,
There is also a possibility that an indentation may be generated at a contact portion of the joint surface of the cylinder head and / or the cylinder block with the bead.

According to the present invention, as described above, the beads formed so as to surround the respective bores between the adjacent bores can more effectively exhibit the sealing characteristics of the beads. In the metal cylinder head gasket of the type arranged in a manner to be arranged, the compression resistance of the bead can be reduced, whereby the bead can be sufficiently compressed with a relatively small tightening axial force to secure a required sealing property. And a metal cylinder head gasket capable of avoiding the generation of cracks in the bead and the generation of indentations on the joint surface due to the bead.

[0006]

SUMMARY OF THE INVENTION A metal cylinder head gasket according to the present invention comprises a bead formed so as to surround each bore between the adjacent bores. It is. A slit is provided at a position between the adjacent beads.

[0007] The slit provided between the beads can reduce the compressive resistance of the bead by reducing the restraining force of the part of the bead adjacent to the slit when the engine is mounted. The bead can be sufficiently compressed by the axial force to secure a predetermined sealing property, and the generation of cracks in the bead and the generation of indentation on the joint surface due to the bead can be avoided.

Further, in the metal cylinder head gasket according to the present invention, the slit is provided in one continuous groove shape, and has a diameter which is continuous with the groove portion at both ends of the slit and is larger than the width thereof. Circular holes can also be provided respectively. By forming the slit in such a form, the workability in the punching process of the slit can be enhanced, the life of the punching die can be extended, and the axial force at the time of mounting the engine, vibration of the slit during use, etc. It is possible to prevent cracks from being generated in the portions due to stress concentration on both end portions.

Further, in the metal cylinder head gasket according to the present invention, the slit is constituted by a pair of groove-shaped portions arranged on one line and spaced apart from each other, and each of the groove-shaped portions is not adjacent to each other. Section has the largest width and reduces its width from the non-adjacent end to the adjacent end, and the non-adjacent end of each groove portion is arcuate It can also be formed so as to bulge outward. By using such a groove-shaped portion, it is possible to improve the workability in punching, prolong the life of the punching die, and prevent the occurrence of cracks at both ends of the slit. With this configuration, the slit can be effectively disposed mainly even when the interval between the bores is too small to form the slit between the adjacent beads.

[0010]

BEST MODE FOR CARRYING OUT THE INVENTION

Embodiment 1 A metal cylinder head gasket according to an embodiment of the present invention, as shown in FIGS. 1 and 2, a bead formed so as to surround each bore 1 between adjacent bores 1 and 1. 2 are arranged adjacent to each other,
A slit 3 is provided at a position P between the beads 2 and 2 adjacent to each other.
Is provided.

The slit 3 has a single continuous groove shape, and at both ends thereof, the slit 3 is continuous with a portion of the groove shape.
Each of the circular holes 4 having a diameter larger than the width W is provided. The longitudinal length and width W of the slit 3 are determined by the distance between the adjacent bores 1 and 1, the distance between the adjacent beads 2 and 2, the dimensions and shape of each bead 2, the applied tightening axial force, and the required tightening. Although it is appropriately selected depending on various factors such as surface pressure, it should be selected so as to secure a sufficient space for deformation absorption so that the bead 2 can smoothly exhibit a predetermined spring property when the engine is mounted. .

On the other hand, in a case where the slit 3 having a sufficient width W cannot be formed between the adjacent beads 2, because the interval between the adjacent bores 1, 1 is small, the adjacent beads 2, 2 are formed by a spring. At the time of sexual deformation, the effect similar to the above can be exerted by separating or separating the beads so that at least each deformation does not interfere with each other, so that the slit 3 has no space or the width W is substantially zero. It can also be provided in the form of a notch.

The metal cylinder head gasket of the present invention configured as described above is mounted on the engine in the same manner as a conventional cylinder head gasket. At this time, when the slit 3 is not provided, the deformation of the bead 2 at the time of compression by the tightening axial force P can be freely deformed on the bore 1 side, while the bead 2 and the bead 2 are mutually deformed as shown by a dotted line in FIG. The deformation on the side adjacent to is restricted. Therefore, the internal deformation force generated by the compression deformation of the bead 2 concentrates on the mutually adjacent portions of the beads 2, and generates a large reaction force S against the bead 2. When the reaction force S is generated, the tightening surface pressure in the adjacent portion between the beads 2 is increased, and the sealing effect is generally the same as that of one bead. On the other hand, in the metal cylinder head gasket of the present invention, since the slit 3 is provided between the beads 2, as shown by a solid line in FIG. Can also be freely deformed, and the above-described reaction force against the bead 2 can be reduced. For this reason, the bead 2 can be sufficiently compressed by a predetermined tightening axial force to secure a predetermined sealing property. Also, since the bead 2 can be sufficiently compressed and mounted with a predetermined tightening axial force, the load stress generated on the bead becomes excessively high, causing cracks in the bead, or excessive surface pressure generated on the bead, resulting in a cylinder head. In addition, it is possible to reliably prevent the indentation due to the contact with the beads on the joint surface of the cylinder block.

Since the slit 3 is provided with the circular holes 4 at both ends thereof, stress concentration at both end portions of the slit due to tightening axial force, vibration during use, or the like is avoided, and a crack is generated at the portion. Can be reliably prevented. In addition, since the slit 3 has holes 4 at both ends thereof to eliminate a sharp-angled portion, the workability at the time of punching is enhanced, and a desired slit shape can be reliably formed. The service life can be extended.

[0015]

Embodiment 2 FIG. 4 is a view showing a metal cylinder head gasket according to another embodiment of the present invention, except that the form of the slit 3 provided at the position P between the adjacent beads 2 is different. This embodiment has the same configuration as that of the embodiment, and is particularly preferable when the interval between the bores 1 and 1 is too small to form the slit 3 between the adjacent beads 2 and 2.

In the present embodiment, the slit 3 is provided in the form of a single continuous groove having holes 4 at both ends, whereas the slit 3 of the above embodiment is spaced apart from each other on a line at a position P. And a pair of groove-shaped portions 5 and 6 arranged in the same manner. The pair of grooved portions 5 and 6 have the greatest width at the non-adjacent ends 5a and 6a and from the ends 5a and 6a to the mutually adjacent ends 5b and 6b. It is formed so as to reduce its width and preferably to be converged and terminated at one point at the ends 5b and 6b.

The longitudinal length of the groove portions 5 and 6 and the width at the end portions 5a and 6a are the same as the longitudinal length of the slit 3 and the width W of the groove-shaped portion described in the above embodiment.
Similarly, the distance between adjacent bores and adjacent beads, the dimensions and shape of the beads, the applied tightening axial force, the required tightening surface pressure, and the like are appropriately selected. It is selected so that a space for securing the sealing property by absorbing the sexual deformation can be secured. On the other hand, the interval between the end portions 5b and 6b adjacent to each other is limited mainly from the viewpoint of processing, but for the above-mentioned reason, it is preferable that the interval is set as small as possible. Therefore, the end 5 of the slit 3
The portions on the b and 6b sides can be formed to extend further in the form of a cut having no space.

The ends 5a, 6a of the groove-shaped portions 5, 6 which are not adjacent to each other are formed so as to bulge outward in an arc shape as shown in the figure. Arc-shaped ends 5a,
6a, like the circular holes 4 provided at both ends of the slit 3 described in the above embodiment, can enhance the workability at the time of punching, reliably form a desired slit shape, and extend the life of the punching die. Can also be longer, and
Avoids stress concentration due to tightening axial force, vibration during use, etc., and reliably prevents cracks from occurring.

In each of the embodiments of the present invention described above, the metal cylinder head gasket of the present invention is illustrated and described taking a one-layer metal gasket as an example. However, the metal cylinder head gasket may be configured as a multi-layer metal gasket. At this time, it is preferable to provide the slit 3 only in a layer having a structure in which the beads 2 of each bore are arranged adjacent to each other between the bores 1 and 1 adjacent to each other. However, when the slits 3 are provided between the same bores 1 and 1 of a plurality of layers, the slits 3 located above and below can smoothly perform the springy deformation of the bead 2 of the layer on the opposite side during assembly and use. It should be provided in position and / or size and shape respectively.

[Brief description of the drawings]

FIG. 1 is a schematic plan view showing a metal cylinder head gasket according to an embodiment of the present invention.

FIG. 2 is a partially enlarged sectional view taken along line II-II of FIG.

FIG. 3 is a schematic diagram for explaining a compression deformation state when the metal cylinder head gasket shown in FIG. 1 is used.

FIG. 4 is a view similar to FIG. 1 showing a metal cylinder head gasket according to another embodiment of the present invention.

[Explanation of symbols]

 1 Bore 2 Bead 3 Slit 4 Hole 5, 6 Groove

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Tomonori Funatsu 2894 Kozu, Kozu, Odawara City, Kanagawa Prefecture Inside Ishino Gas Sket Kogyo Co., Ltd. (72) Inventor Kazuto Tomokin No. 2 Takaracho, Kanagawa-ku, Yokohama-shi, Kanagawa F-term in Nissan Motor Co., Ltd. (reference) 3J040 AA01 AA12 BA01 EA08 EA18 FA01 HA01 HA02 HA17 HA30

Claims (3)

[Claims] 1. A metal cylinder head gasket in which beads formed between adjacent bores to surround each bore are disposed adjacent to each other, wherein a position between the adjacent beads is provided. A gasket, characterized in that a slit is provided in the gasket. 2. The slit has a continuous groove-shaped body, and circular holes having a diameter larger than the width of the groove are provided at both ends of the slit. The gasket according to claim 1, wherein the gasket is provided. 3. The slit comprises a pair of groove portions arranged on a line and spaced apart from each other, each groove portion having a largest width at an end on a side which is not adjacent to each other, and The width decreases from the non-adjacent end to the adjacent end, and the non-adjacent end of each groove-shaped portion is formed to bulge outward in an arc shape. The gasket according to claim 1, wherein the gasket is formed.