JPH07158507A - Cylinder head gasket - Google Patents

Abstract

PURPOSE:To provide the seal structure of fluid holes matching the surface pressure caused by clamping a cylinder head to a cylinder block. CONSTITUTION:Seal performance in a clamping direction of the seal structure of fluid holes 34b, 34c, 34d of a cylinder head gasket 20 placed in the vicinity of a head bolt to clamp the intermediate part of the cylinder head in an air cylinder row direction is enhanced higher than the seal performance in the clamping direction of the seal structure of fluid holes 34a, 34e of the cylinder head gasket 20 placed in the vicinity of the head bolt to clamp together both ends of the cylinder head in the air cylinder row direction.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a seal structure for a fluid hole of a cylinder head gasket provided between a cylinder head and a cylinder block, and more particularly to a cylinder having a fluid hole sealing structure according to a surface pressure due to fastening. Regarding head gasket.

[0002]

2. Description of the Related Art As an example of prior art relating to a cylinder head gasket, Japanese Utility Model Laid-Open No. 4-1778 is known. In the gasket of this publication, a rubber ring is provided in the fluid hole to enhance the sealing property. By providing the rubber ring in the fluid hole, the sealing function can be sufficiently maintained even if the relative displacement amount of the cylinder head and the cylinder block during the engine operation is large.

FIG. 6 shows an example of a conventional cylinder head gasket used in an in-line four-cylinder engine. In FIG. 6, reference numeral 1 denotes a cylinder head gasket. Four combustion chamber holes 2 are formed in the cylinder head gasket 1. In the vicinity of the combustion chamber hole 2 of the cylinder head gasket 1, a plurality of bolt holes 3a to 3j into which head bolts for fastening a cylinder head and a cylinder block (not shown) are inserted are formed.

The bolt holes 3a to 3e are arranged on one side of the combustion chamber holes 2 arranged in a straight line. Bolt holes 3f-3j
Are arranged on the other side of the combustion chamber holes 2 arranged in a straight line. The cylinder head gasket 1 has bolt holes 3f ...
Fluid holes 4a to 4e are provided adjacent to 3j. Each of the fluid holes 4a to 4e is used as a flow path for returning the oil supplied to the cylinder head to the crankcase side and for flowing the blow-by gas. A thin metal plate called a metal eyelet is fixed around the fluid holes 4a to 4e, and a rubber O-ring is attached to the inside of each of the fluid holes 4a to 4e in order to enhance the sealing property.

[0005]

However, the cylinder head gasket shown in FIG. 6 has the following problems.
The axial force (compressive force) due to the tightening of the head bolt inserted into the bolt hole 3f located at the left end in FIG. 6 acts only on the # 1 cylinder, and the head bolt inserted into the bolt hole 3j located at the right end in FIG. The axial force due to the tightening of No. 4 acts only on the # 4 cylinder. On the other hand, the axial force due to the tightening of the head bolt inserted into the bolt hole 6g acts on both the # 1 cylinder and the # 2 cylinder, and the axial force due to the tightening of the head bolt inserted into the bolt hole 6h is It works on both # 2 and # 3 cylinders. Similarly, the axial force due to the tightening of the head bolt inserted into the bolt hole 6i acts on both the # 3 cylinder and the # 4 cylinder.

Here, comparing the axial forces acting on the fluid holes 4a and 4b among the fluid holes 4a to 4e of the cylinder head gasket 1, the axial force acting on the fluid hole 4a is the fluid hole. It is larger than the axial force acting on 4b. Therefore, the surface pressure in the vicinity of the fluid hole 4a becomes higher than the surface pressure of the fluid hole 4b, and the sealing performance of the fluid hole 4a is significantly improved as compared with the sealing performance of the fluid hole 4b. Similarly, the sealing performance of the fluid hole 4e located at the right end of the cylinder head gasket 1 is also improved.

Thus, the cylinder head gasket 1
Although the sealability of the fluid holes 4a, 4b located at both ends of the is improved, mounting the rubber O-rings in the fluid holes 4a, 4e causes a problem of increasing cost. Therefore, it is desired to employ a seal structure suitable for the surface pressure in the cylinder head gasket.

An object of the present invention is to provide a cylinder head gasket capable of obtaining a fluid hole sealing structure according to a surface pressure due to fastening of a cylinder head and a cylinder block.

[0009]

A cylinder head gasket according to the present invention for attaining this object is a cylinder head gasket provided between a cylinder head and a cylinder block fastened by a plurality of head bolts. The head bolts that fasten both ends of the cylinder head in the cylinder row direction to the fastening performance of the sealing structure of the fluid hole of the cylinder head gasket located near the head bolts that fasten the middle portion of the cylinder head in the cylinder row direction. The cylinder head gasket has a fluid hole having a sealing property higher than that of the sealing structure in the fastening direction.

[0010]

In the thus constructed cylinder head gasket, the surface pressure of the cylinder head gasket due to the fastening of the cylinder head and the cylinder block varies depending on the position in the cylinder row direction. That is, since the fastening force by the head bolt located in the middle portion in the cylinder row direction is distributed to both cylinders, the surface pressure of the cylinder head gasket near this is small. Since the fastening force by the head bolt located at the end in the cylinder row direction is concentrated on one cylinder, the surface pressure of the cylinder head gasket in the vicinity of this is large.
Since the sealability of the cylinder head gasket where the surface pressure is high is extremely high in the fastening direction, it is possible to secure sufficient sealability without using a sealing member such as a rubber ring. It suffices to improve the sealing property only by the rubber ring or the like only in the sealing structure portion of the hole. Therefore, it is possible to satisfy the required sealing property without providing the same sealing structure for all the fluid holes of the cylinder head gasket, and it is possible to obtain the sealing structure according to the surface pressure.

[0011]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Preferred embodiments of the cylinder head gasket according to the present invention will be described below with reference to the drawings. 1 to 5 show one embodiment of the present invention, particularly when applied to an in-line four-cylinder engine. In FIG. 1, reference numeral 20 indicates the entire cylinder head gasket. The cylinder head gasket 20 is provided between the cylinder head 50 and the cylinder block 52 of the engine shown in FIG. Cylinder head gasket 2
Reference numeral 0 is composed of the gasket body 22 and a plurality of parts attached thereto.

As shown in FIG. 2, the gasket body 22 is composed of a thin metal plate 24 as a core metal and carbon graphite 26. The thin metal plate 24 has a thickness of 0.2 mm, for example. The carbon graphite 26 is baked on both surfaces of the thin metal plate 24. The thickness of the gasket body 22 is, for example, 1.3 mm
Has become. The gasket body 22 is provided with four combustion chamber holes 28 at predetermined intervals. A metal bore grommet 30 is fixed to the inner peripheral surface of the combustion chamber hole 28 by caulking.

Bolt holes 32a to 3 into which the head bolts 54 for fastening the cylinder head 50 and the cylinder block 52 shown in FIG.
A plurality of 2j are provided. Bolt holes 32a to 32e
Are arranged on one side of the combustion chamber holes 28 arranged in a straight line. The bolt holes 32f to 32j are arranged on the other side of the combustion chamber holes 28 that are linearly arranged. In the gasket body 22, the fluid holes 34a to 32j are adjacent to the bolt holes 32f to 32j.
34e is provided. The fluid hole 34b functions as a gas passage through which blow-by gas flows. Fluid hole 34
The a, 34c, 34d and 34e function as oil passages for returning the oil supplied to the cylinder head to the oil pan.

The gasket body 22 is provided with an oil hole 36 for supplying oil to the cylinder head 50 side.
The oil hole 36 overlaps with the bolt hole 32d. The gasket body 22 has a plurality of water holes 38. The water hole 38 functions as a part of a cooling water passage through which cooling water flows. The # 1 combustion chamber hole 28 of the gasket body 22
A blow-by gas hole 40 through which the blow-by gas flows is provided near.

Each bolt hole 32a of the gasket body 22
A metal grommet 42 is provided around 32j, around each fluid hole 34a to 34e, and around the blow-by gas hole 40. The metal grommet 42 is made of a thin metal plate and is fixed to the gasket body 22 by caulking. The metal grommet 42 reinforces the portion of the gasket body 22 to which the tightening force of the head bolt 54 acts.

A fluid hole 34b located between the # 1 cylinder and the # 2 cylinder, a fluid hole 34c located between the # 2 cylinder and the # 3 cylinder, and a fluid hole 34c located between the # 3 cylinder and the # 4 cylinder. A rubber ring 44 as a seal ring that enhances the sealing performance in the fastening direction is provided in the fluid hole 34d located. The rubber ring 44 is connected to a support arm 46 made of a thin metal plate. A through hole 47 for allowing a fluid to pass through is provided in a portion of the support arm 46 located inside the rubber ring 44.

The end of the support arm 46 is fixed to a holding hole 48 formed in the gasket body 22 by caulking. As a result, the rubber ring 44 is supported by the gasket body 22 via the support arm 46.
2 and 3, only the seal structure of the fluid hole 34c located between the # 2 cylinder and the # 3 cylinder is shown, but the seal structure of the fluid hole 34b and the fluid hole 34d also conforms to this.

FIG. 4 shows the sealing structure of the fluid hole 34a of the cylinder head gasket 20 located near the head bolts 54 for fastening both ends of the cylinder head 50 in the cylinder row direction. FIG. 4 shows the fluid hole 34a on the # 1 cylinder side.
Unlike the seal structure of FIG. 2, the rubber hole 44 is not provided in the fluid hole 34a. Similarly, the rubber ring 44 is not provided in the fluid hole 34e on the # 4 cylinder side.

Next, the operation of the above cylinder head gasket will be described. The cylinder head gasket 20 is provided between the cylinder head 50 and the cylinder block 52 shown in FIG. 5, and the cylinder head 50 is fastened to the cylinder block 52 via a head bolt 54. Here, since the fastening force of the head bolt 54 located between the # 2 cylinder and the # 3 cylinder is distributed to the # 2 cylinder and the # 3 cylinder, the surface pressure near the fluid hole 34c of the cylinder head gasket 20 is It will be small. For the same reason,
The surface pressure near the fluid hole 34b and near the fluid hole 34d of the cylinder head gasket 20 is also small.

On the other hand, since the fastening force by the cylinder head bolts 54 located at the ends in the cylinder row direction is concentrated on one cylinder, the surface pressure in the vicinity of the fluid hole 34d adjacent to the # 1 cylinder and the adjacent # 4 cylinder. The surface pressure near the fluid holes 34e is higher than the surface pressure near the other fluid holes 34d to 34i. As described above, since the sealing property in the tightening direction is significantly enhanced at the portion where the surface pressure of the cylinder head gasket 20 is high, the fluid holes 34a and 34e should be sufficiently secured even without using the rubber ring 44. Is possible.

Further, since the rubber ring 44 is not necessary for the fluid holes 34a and 34e, it is possible to avoid the deterioration of the sealing property due to the deterioration of the rubber ring 44, and the sealing structure of the fluid holes 34a and 34e is the other fluid holes 34b to 34d. The durability in the fastening direction can be improved. As a result, the seal structure of the fluid holes 34a and 34e located at both ends is the same as the fluid hole 34b in the middle portion.
The sealing structure of ~ 34d is stronger than the sealing property against the compression load and can maintain a good sealing property for a long period of time.

During operation of the engine, the relative movement between the cylinder head 50 and the cylinder block 52 due to explosive load or thermal deformation becomes large. As shown in FIG. 5, this tendency is particularly noticeable at the center of the cylinder head 50 in the cylinder arrangement direction. It gets bigger in the department. In the fluid holes 34b, 34c, 34d located in the center portion of the cylinder head gasket 20 in the cylinder row direction,
Since the rubber ring 44 is provided, the rubber ring 44 elastically deforms following the displacement of the gap between the cylinder head 50 and the cylinder block 52 during the operation of the engine, so that the fluid holes 34b, 34c, 34d are formed. Sufficient sealing property is ensured.

In this embodiment, the fluid holes 34b, 34c, 3
Although the rubber ring 44 is used as a means for enhancing the sealing property of 4d, a bead or a shim (gap adjusting plate) protruding in the fastening direction may be used as an alternative means.
The structure of the gasket body 22 is not limited to this embodiment, and may be a structure in which a plurality of thin sheet metals are laminated.

[0024]

According to the present invention, the sealing performance in the fastening direction of the sealing structure of the fluid hole of the cylinder head gasket located near the head bolt fastening the intermediate portion of the cylinder head in the cylinder row direction is Since the sealing performance of the fluid hole of the cylinder head gasket located near the head bolts that fastens both ends in the cylinder row direction is higher than the sealing performance in the fastening direction, the fluid hole is sealed according to the surface pressure due to fastening. The structure can be obtained. Therefore, in the seal structure of the fluid hole located at the end portion in the cylinder row direction where the surface pressure becomes high, it is possible to sufficiently secure the sealability without using a seal member such as a rubber ring. The cost of the gasket can be reduced.

[Brief description of drawings]

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

FIG. 2 is a sectional view taken along the line AA of FIG.

3 is a cross-sectional view taken along the line BB of FIG.

FIG. 4 is a cross-sectional view taken along the line CC of FIG.

5 is a side view showing a seal structure between a cylinder head and a cylinder block using the cylinder gasket of FIG.

FIG. 6 is a plan view showing an example of a conventional cylinder head gasket.

[Explanation of symbols]

 20 Cylinder head gasket 32f Bolt hole located at the end in the cylinder row direction 32j Bolt hole located at the end in the cylinder row direction 32g Bolt hole located in the middle part in the cylinder row direction 32h Located in the middle part in the cylinder row direction Bolt hole 32i Bolt hole located in the middle portion in the cylinder row direction 34a Fluid hole located in the end portion in the cylinder row direction 34e Fluid hole located in the end portion in the cylinder row direction 34b Fluid hole located in the middle portion in the cylinder row direction 34c Fluid hole located in the middle portion in the cylinder row direction 34d Fluid hole located in the middle portion in the cylinder row direction 44 Rubber ring 50 Cylinder head 52 Cylinder block 54 Head bolt

Claims (1)

[Claims] 1. A cylinder head gasket provided between a cylinder head fastened by a plurality of head bolts and a cylinder block, wherein the cylinder is located near the head bolt fastening an intermediate portion of the cylinder head in the cylinder row direction. The sealing property of the sealing structure of the fluid holes of the head gasket in the fastening direction is determined by the sealing property of the sealing structure of the fluid structures of the cylinder head gasket located near the head bolts that fasten both ends of the cylinder head in the cylinder row direction. Cylinder head gasket characterized by being higher than