JPH0972423A - Bead for oiling hole - Google Patents

Abstract

PROBLEM TO BE SOLVED: To improve the sealing performance of a bead for a metallic cylinder head gasket oiling hole wherein an oiling hole bead and a bolt hole bead are integrally formed. SOLUTION: An oiling hole bead 1 surrounding the oiling hole 3 and the bolt hole 4 of a cylinder head gasket 2 is formed by one bead, a rising angle θ2 in the bolt hole 4 side is set smaller than a rising angle θ1 in the oiling hole 3 side and the width t1 of the top part of the bolt hole 3 side is formed narrower than the width t2 of that of the oiling hole 4.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an oil hole bead, and more particularly to a sealing bead provided in an oil hole of a cylinder head gasket made of a thin metal plate.

[0002]

2. Description of the Related Art Cylinder head gaskets provided between a cylinder head and a cylinder body of an internal combustion engine include a cylinder hole forming a combustion chamber, lubricating oil, cooling water,
There are many holes for head bolts and push rods. With the increase in output of engines, metal gaskets made of thin metal plates have come to be widely used not only for diesel engines generally used for high output, but also for gasoline engines.

[0003] The seal of a metal gasket is usually provided around a hole to be sealed with a bead in which a metal plate is bulged in a loop shape, and the metal of the gasket is pressed by a reaction force generated when the gasket is tightened to compress the bead. The space between the boards is pressed against the deck surface for sealing. As is well known, cylinder holes are arranged in a horizontal row on the joint surface between a cylinder head and a cylinder body of a multi-cylinder in-line internal combustion engine, and the various holes are arranged around the cylinder holes. And, the head bolt is around the cylinder hole that becomes high pressure,
Since it is arranged to exert a more uniform tightening force,
The liquid holes such as oil holes and water holes are located unevenly with respect to the head bolts, and there is a problem that the tightening force of the beads provided in the liquid holes is not uniform.

Further, in order to reduce the weight of the engine and to provide high output,
In recent years, aluminum alloy cylinder heads have come into use. Therefore, the cylinder head is likely to be subjected to the reaction force of the bead and the deformation force of the center portion thereof to be warped, and the tightening force of the bead provided in the liquid hole tends to be more uneven. By the way, the oil passage is provided for lubrication of the valve mechanism provided in the upper part of the cylinder head, and since there are few parts directly related to the cylinder body and the cylinder head, it has hitherto been projected from the corner part of the engine or the main body. It is often installed in the part where it is installed. Therefore, the tendency that the tightening force by the head bolt becomes uneven becomes more remarkable than that of the water hole.

Therefore, the oil passage is arranged near the head bolt so that the tightening force of the bolt can be easily exerted, so that the oil hole bead of the cylinder head gasket is
Conventionally, the oil hole beads are formed so as to surround the bolt holes so as not to interfere with the bolt holes. In order to improve the sealing performance by this common bead, the applicant of the present invention has devised to set the bead spring constant to a smaller value on the oil hole side than on the bolt hole side.
101061).

[0006]

By the way, as is well known, there is a demand from the market for higher performance of internal combustion engines, especially automobile internal combustion engines, and improvements are constantly being made. Along with this, higher performance is also required for the seal of the oil hole of the cylinder head gasket.

The present invention has been made in view of the above problems. In a metal cylinder head gasket in which a bead for an oil hole is integrally formed with a bead for a bolt hole, an oil hole having a further improved sealing performance is provided. Providing beads for use is a challenge to solve.

[0008]

In order to achieve the above object, the oil hole bead according to the present invention has an oil passage extending from the cylinder body to the cylinder head on the outer peripheral side of the engine near the head bolt. An oil hole for the oil passage and a bolt hole for the head bolt are formed in a metal cylinder head gasket for an internal combustion engine, and beads surrounding the holes are formed by one bead common to both holes. However, the cross-sectional shape of the bead in the width direction is formed such that the rising angle on the bolt hole side is smaller than the rising angle on the oil hole side, and the top width on the bolt hole side is narrower than the top width on the oil hole side.

As means for forming the bead on the oil hole side so as to be wider than the bolt hole side,
The bead width and the bead height can be kept constant, and the bead rising angles on both sides in the bead width direction can be adjusted. However, the present invention is not limited to this, and may be performed by other means such as changing the bead width or the bead height.

There is no particular limitation on the change in the apex shape and the rising angle of the beads on the oil hole side and the bolt hole side, and they may be changed stepwise, but in general, the bead hole side and the oil hole side are changed. It is preferable to gradually change, for example, continuously changing between. Also, the cross-sectional shape of the bead is not particularly limited, but when compressed, the top of the bead on the oil hole side bends in a valley shape and is easily trapezoidal or more trapezoidal so as to easily form an inverted W shape. It can be shaped.

The oil hole and the bolt hole are surrounded by one bead, and the cross-sectional shape in the width direction of the bead has a rising angle on the oil hole side larger than a rising angle on the bolt hole side and a top width on the oil hole side. With the means formed wider than the top width on the bolt hole side, the bead is easily deformed into an inverted W shape with a lower tightening load, so that the restoring force and the restoring amount to be restored are increased.

[0012]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below in detail with reference to the accompanying drawings. The oil hole bead 1 of the first embodiment shown in FIGS. 1 and 2 surrounds both an oil hole 3 and a bolt hole 4 formed in a cylinder head gasket (hereinafter simply referred to as a gasket) 2 made of a single plate. It is provided.

The oil hole 3 has an outer periphery 5 of the gasket 2.
Is provided at the corner portion of the cylinder and is located on the opposite side of the cylinder hole 6 with respect to the bolt hole 4. A plurality of bolt holes (other than the bolt holes 4 are not shown) are arranged around the cylinder hole 6. Reference numeral 7 shown in FIG. 1 is a water hole, 8 is a cylinder hole bead, and 9 is a water hole bead.

The oil hole bead 1 is formed in a trapezoidal shape having a constant bead width W and height h, as shown in FIG. Then, the rising angle θ ₁ of the bolt hole 4 side A is formed smaller than the rising angle θ ₂ of the oil hole side B (θ ₁ <θ ₂ ), and the width t ₁ of the top of the bolt hole side A is set to the oil hole side B. Was formed so as to have a width (width t ₁ <t ₂ ) narrower than the top width t ₂ .

The dimensions of each part of the trapezoidal bead are not constant depending on the specifications of the target internal combustion engine, but in the case of an ordinary cylinder head gasket, W is generally 1.5 to 3 mm, h is 0.2 to ₁ mm, and w ₁ is Around 1.5 mm, t ₁ is 0.5
.About.1.0 mm, w ₂ is ₂ to 3 mm, and t ₂ is 1.0 to ₂ .
The value is preferably about 0 mm. In general, waveforms,
When a bead having a cross-sectional shape in the width direction such as an arc is compressed, the apex is bent to the opposite side and deformed into an inverted W shape. In the case of the oil hole bead 1 formed as described above, the apex on the oil hole 3 side is formed. Since t ₂ is formed wide, it is easy to bend,
As shown in FIG. 3, an inverted W shape is easily obtained. When this inverted W type is further compressed, the bead width W is deformed more uniformly,
When the rising angle is small, a more uniform reaction force can be obtained, and a weaker compressive force can generate a more uniform surface pressure over the entire bead width W. The symbols shown in FIG.
Reference numeral 10 is a cylinder head, 11 is a cylinder body, and 12 is an oil passage formed in the cylinder head 10 and the cylinder body 11.

On the other hand, on the bolt hole 4 side, when compressed, the width of the top t ₁ is narrow and the rising angle is small, so the bead can be easily compressed. By the way, the tightening force of the bolt (not shown) acts more uniformly on the cylinder hole 6 side, but the oil hole 3 is in a partially tightened state. Further, the tightening force pulsates due to the operation of the internal combustion engine (not shown), and the effect is that the tightening condition on the oil hole side B of the oil hole 3 has a larger pulsation amplitude than on the bolt hole side A.

However, in the oil hole bead 1 of the first embodiment, the outer periphery 5 side where the tightening force is weak and the pulsation of the tightening force is severe can be compressed with a weak tightening force, and is deformed into an inverted W shape. The pulsation can be easily expanded and contracted, and high sealing performance can be maintained. The oil hole bead 1 according to the second embodiment shown in FIG. 4 is formed by a laminated cylinder head gasket 13 and has a cross-sectional shape in the width direction formed in a continuous arc shape. The oil hole bead 1 of Example 2 also provided the same high sealing performance as the oil hole bead 1 of Example 1. Reference numeral 14 shown in FIG. 4 is a head bolt.

[0018]

As described above, in the bead for an oil hole of the present invention, the cross-sectional shape in the width direction is such that the rising angle on the bolt hole side is smaller than the rising angle on the oil hole side, and the top width on the bolt hole side is the oil. Since it is formed narrower than the top width on the hole side, the entire bead width is compressed more uniformly on the outer peripheral side part of the gasket where a lower compression force acts, generating a wide surface pressure, and following the pulsating compression force. It was possible to maintain high sealing performance and improve the reliability of the cylinder head gasket.

[Brief description of drawings]

FIG. 1 is a partial plan view of an oil hole bead according to a first embodiment of the present invention.

2A is a sectional view taken along line IIA-IIA of FIG.
2B is a sectional view taken along line IIB-IIB in FIG. 1.

FIG. 3 is an explanatory view showing a state where the bead cross section shown in FIG. 2 is deformed.

FIG. 4 is a partial sectional view of an oil hole bead according to a second embodiment of the present invention.

[Explanation of symbols]

1 Bead for oil hole 2 Gasket (cylinder head gasket) 3 Oil hole 4 Bolt hole 5 Outer circumference 6 Cylinder hole 11 Cylinder body 12 Oil passage 13 Multi-layer cylinder head gasket 14 Head bolt A Bolt hole side B Oil hole side h Height t ₁ width t ₂ width W bead width w ₁ width w ₂ width θ ₁ rising angle θ ₂ rising angle

Claims (3)

[Claims] 1. A metal cylinder head gasket for an internal combustion engine, wherein an oil passage communicating from a cylinder body to a cylinder head is formed on an outer peripheral side of the engine near the head bolt, and an oil hole for the oil passage and the head bolt are provided. Bolt holes are formed, and the beads surrounding these holes are formed by one bead that is common to both holes, and the cross-sectional shape in the width direction of this bead is raised on the bolt hole side from the rise angle on the oil hole side. A bead for an oil hole with a small angle and a top width on the bolt hole side narrower than a top width on the oil hole side. 2. The oil hole according to claim 1, wherein the top shape and the rising angle of the bead on the oil hole side and the bolt hole side are gradually changed between the bolt hole side and the oil hole side. Beads. 3. The bead for an oil hole according to claim 1, wherein the bead has a trapezoidal sectional shape.