JP2005180660A - Cylinder head gasket - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a cylinder head gasket which is equipped as thing capable of applying a stopper part formed on a circumferential part of a through hole of a bore etc. even to narrow place in width without incurring difficult processing technique and very large cost rise in order to intend an enhancement in effective sealing performance. <P>SOLUTION: In the cylinder head gasket including a metallic substrate 2 and the annular stopper part 3 formed on a circumferential part of the bore 2a opened on the metallic substrate 2, the stopper part 3 is formed by shot coating with aluminium powder to the metallic substrate 2. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a cylinder head gasket having a metal substrate and an annular stopper portion formed in a peripheral portion of a through hole provided in the metal substrate.

  As a cylinder head gasket interposed between a cylinder block and a cylinder head in an engine, a metal substrate made of stainless steel plate or the like, and an annular metal stopper formed around the circular hole of the cylinder bore in the metal substrate And a structure having As such a cylinder gasket, for example, the one disclosed in Patent Document 1 is known.

  This is because an annular stopper is provided at the periphery of the bore hole of the cylinder head gasket that requires strict pressure resistance and sealability, and the thickness of the periphery of the bore hole is made larger than the other portions. Thus, the surface pressure of the gasket in the cylinder bore portion is increased to meet these requirements. In the above-mentioned patent document 1, it is disclosed that the stopper portion is formed by spraying a resin material or the like around the bore hole of the cylinder head gasket.

  Since high pressure due to combustion acts on the periphery of the bore hole, in order to further enhance the sealing function (sealability) by interposing a gasket, a stopper formed on the periphery of the bore hole is made of a metal material. It seems to be preferable. Therefore, the following means 1) to 4) have been considered as stopper portions (also referred to as “shim portions”) formed around the bore hole as an example of the through hole.

1) A structure in which a thin metal plate 11 in a ring shape is stamped and formed, and is superimposed on a peripheral portion of the bore hole 12a in the metal substrate 12 and integrated by welding (see FIG. 8).
2) A structure in which the ring-shaped stopper portion 13 is formed on the metal substrate 12 by folding the metal substrate 12 through the bore holes 12a (see FIG. 9).
3) A structure in which the stopper portion 14 having an increased thickness is formed by coining the peripheral portion of the bore hole 12a in an annular shape (see FIG. 10).
4) A structure in which the stopper portion 15 having an increased thickness is formed by corrugating the periphery of the bore hole 12a in an annular shape (see FIG. 11).
Japanese Patent Laid-Open No. 64-035057

  However, the following problems existed in the proposed means 1) to 4). That is, in the method 1), the welding process increases the cost, and in the method 2), the metal substrates are stacked, so that the thickness of the portion tends to be too thick. In the means 3) and 4), high technology is required for processing, the equipment cost is high, and since plastic processing is applied to the core material, when it is used as a cylinder head gasket, “warping” occurs and it is easy to deform. There was a problem.

  In addition, any of these means 1) to 4) is difficult to be established in a narrow portion, the application conditions are limited, and the general versatility of the technology is inferior. As a stopper part formed in the peripheral part, there is room for further improvement.

  Therefore, in order to improve the effective sealing performance, the present invention provides a stopper portion formed in the peripheral portion of a through hole such as a bore hole without incurring a difficult processing technique and a significant cost increase, and having a wide width. It aims at providing the cylinder head gasket equipped as what can be applied also to a narrow place.

The structure of claim 1 is a cylinder head gasket comprising a metal substrate and an annular stopper portion formed in a peripheral portion of a through hole provided in the metal substrate.
The stopper portion is formed by shot coating of metal powder on the metal substrate.

The structure of claim 2 is the structure of claim 1,
The through hole is a bore hole formed corresponding to a cylinder bore.

The structure of claim 3 is the structure of claim 1 or 2,
An annular bead portion protruding in the gasket thickness direction is formed on the outer peripheral portion of the stopper portion in the metal substrate.

The configuration of claim 4 is any one of claims 1 to 3,
The metal powder is a powder made of an aluminum material.

The structure of Claim 5 is set in any one of Claims 1-4,
A coating layer made of a rubber material is formed on the outer surface of the metal substrate and the outer surface of the stopper portion.

The configuration of claim 6 is any one of claims 1 to 5,
The thickness of the stopper portion is changed as necessary in the circumferential direction.

  In the configuration of claim 1, since the annular stopper portion formed in the peripheral portion of the through hole is formed by shot coating of metal powder, the injection conditions such as the width and thickness of the stopper portion, the coating location on the metal substrate, etc. Can be set freely. The shot coating method does not require heat treatment, has a short coating time, and is excellent in workability. Therefore, coating can be performed even in a narrow place, the conventional constraint condition is solved, and processing that requires high time and cost such as welding becomes unnecessary. In addition, since processing requiring high power such as coining is not required, a large-scale facility is not required, and a high facility cost is not required. Furthermore, since the metal substrate is not subjected to plastic working, the risk of deformation such as warpage is eliminated.

  As a result, it becomes possible to easily form a stopper portion having a thickness as required at a necessary portion in the cylinder head gasket, and is formed around the through hole such as a bore hole in order to improve effective sealing performance. It is possible to provide a cylinder head gasket equipped with a stopper portion that can be applied to a narrow portion without incurring difficult processing techniques and significant cost increase. Such an effect can be remarkably obtained at the stopper portion in the peripheral portion of the bore hole where high sealing performance is required as in the second aspect.

  In the structure of Claim 3, while having the said effect by the structure of Claim 1 or 2, there exists an advantage which a sealing performance improves more by providing a bead part. That is, the stopper portion functions as the primary seal portion, and the bead portion functions as the secondary seal portion, and a synergistic effect can be expected from the double seal at the portion exhibiting high sealing performance.

  According to the fourth aspect of the present invention, since the metal powder is a powder made of an aluminum material which is a soft metal, a metal film having a thickness of several microns can be satisfactorily formed on the surface of the metal substrate. And when interposed between the cylinder block and the cylinder head and tightened, it is easily deformed because of the soft metal, and can follow the surface shape of the cylinder head to obtain better sealing performance. There are advantages.

In the structure of Claim 5, since the coating layer by a rubber material is formed in the outer surface of a metal substrate and the outer surface of a stopper part, there exists an advantage which the protection function with respect to the surface of these metal substrates and a stopper part arises. When the cylinder block and the cylinder head are interposed and tightened, the coating layer easily deforms to follow the cylinder block and the cylinder head, and the sealing performance can be further improved.

  In the structure of claim 6, since the thickness of the coating can be changed in any way by the shot coating of the metal powder, the thickness of the stopper portion can be changed as necessary. It becomes possible to further improve the sealing performance. For example, for a bore hole, a cylinder head that is tightened with a bolt to a cylinder block by changing the thickness so that the thickness is reduced at a portion close to the bolt for tightening and between adjacent bolts. However, the bolt portion can be adapted to the situation where it is bent and deformed by being strongly tightened, and an effective sealing performance can be obtained at any portion in the circumferential direction.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings.

  1 is a plan view of a cylinder head gasket 1 applicable to an internal combustion engine mounted on an automobile or the like, FIG. 2 is a sectional view taken along line aa in FIG. 1, and FIG. An enlarged view of the vicinity of the bore hole in FIG. 2 is shown. The cylinder head gasket 1 is interposed between a cylinder block (not shown) and a cylinder head (not shown).

  The cylinder head gasket 1 is formed with various through holes H, that is, circular bore holes 2a, bolt holes 2b, belt insertion holes 2c for camshaft transmission, cooling water holes or oil holes 2d corresponding to the cylinder bores. Metal substrate 2, an annular bore stopper portion 3 formed in the peripheral portion of the bore hole (an example of the through hole H) 2a provided in the metal substrate 2, and a rubber material formed on the outer surfaces of the front and back surfaces The coating layer 4 is made up of. An annular bolt hole stopper portion 7 similar to the bore stopper portion 3 is also formed at the periphery of 10 bolt holes (an example of the through hole H) 2b formed around each bore hole 2a.

  A ring-shaped bead portion 5 formed by bending the metal substrate 2 and protruding in the same direction as the stopper portion 3 is formed at the outer peripheral portion of each bore stopper portion 3, and at the outer peripheral edge portion of the metal substrate 2. A half bead portion 6 is formed by bending the metal substrate 2 and slightly raising it in the same direction as the bore stopper portion 3. The height of the bead portion 5 is formed to be slightly higher than the bore stopper portion 3.

  The metal substrate 2 is preferably made of a material that has elasticity and viscosity and can be pressed, and a rolled steel plate (SPCC, SPHC, etc.) that has no (or few) surface properties and processing restrictions is suitable. Other than this, a plate material having a dense surface roughness, a plate material having a plated surface or a ceramic coating surface is also possible.

  The bore stopper portion 3 and the bolt hole stopper portion 7 are formed by shot coating of metal powder on a metal substrate, and the metal powder is made of an aluminum material. The thickness by shot coating can be freely selected and set within a range from a thin one of 10 μm to a thick one of 500 μm.

  Since the aluminum powder is sprayed at high speed to form a film on the metal substrate 2, the stopper portions 3 and 7 are formed, so the width, thickness, location, etc. of the stopper portions 3 and 7 can be freely adjusted by adjusting the injection conditions. There is an advantage that can be selected and set. The bore stopper portion 3 has an advantage that it is easy to process and costs less than the conventional means (see FIGS. 6 to 9).

  Because of the rigidity, a large and small gap is generated between the cylinder block and the cylinder head when bolts are tightened. Therefore, if the thickness of the stopper portions 3 and 7 in the cylinder head gasket 1 is set in advance, the thickness at the time of tightening can be reduced. The deformation of the cylinder block and the cylinder head can be reduced.

  As shown in FIG. 3, the coating layer 4 made of a rubber material is formed on both the front and back surfaces of the metal substrate 2 and the outer surface of the bore stopper portion 3, although not shown, on the outer surface of the bolt hole stopper portion 7. Is also formed. In addition, as shown by a virtual line in FIG. 3, a vertical wall-like coating layer 4 'covering the end face of the bore hole 2a may be formed.

  Here, shot coating will be described. Shot coating means the formation of an impact film. When a soft metal powder such as aluminum is sprayed onto the surface of a base material (metal substrate 2 in the present invention) at high speed, erosion is initially generated on the surface of the base material. However, a soft metal film having a thickness of several microns is formed on the surface of the substrate. When metal powder is jetted at high speed from a nozzle toward the substrate using compressed air, the kinetic energy of the metal powder is instantaneously converted into heat, and a metal film is formed with a large plastic deformation.

  When the metal powder is aluminum powder, the powder is an atomized powder having an average particle diameter of about 45 μm and a purity of 99.7% or more. The test conditions in this case are as follows. Two types of plain substrates of silicon nitride (Si3N4: density 3.3 Mg / m3) were used as the ceramic base material to which the shot coating was applied. Shot coating was performed by spraying aluminum powder at a high temperature at normal temperature using an induction suction type blasting apparatus. The coating conditions were such that the distance from the nozzle tip to the substrate was 10 mm, and the injection air pressure was 1 MPa.

  In shot coating with aluminum powder, it has been found that a dense film is formed on a silicon nitride substrate with a thickness of several microns. Furthermore, when observing in detail the inside of the aluminum film and the interface with the silicon nitride substrate, the shape of the aluminum powder sprayed at high speed into the inside of the film cannot be discriminated, and there is no unbonded part or peeling at the interface between the film and the material. I found that it was not allowed. As described above, the technique of shot coating on the ceramic base material is applied to the metal substrate in the present invention, and as described above, various effects can be obtained.

  As the through hole H, there may be a belt insertion hole 2c, a cooling water hole or an oil hole 2d in addition to the bore hole 2a and the bolt hole 2b, and a stopper part formed by shot coating metal powder around these peripheral parts. The structure to be formed is also possible.

  The thickness of the stopper 3 can be coated in the range of 0.1 to 10 μm in the case of means such as ion plating and sputtering, and in the case of means of thermal spraying, the thickness of 0.1 to 1.0 mm is applied. Is possible. On the other hand, in the means by shot coating of metal powder (means according to the present invention), the thickness of the stopper portion 3 is in the range of 10 to 500 μm (0.01 to 0.5 mm), which is an intermediate value between the two. There is an advantage that the thickness can be created.

  In the cylinder head gasket 1, when the raised state of the bead portion 5 of the metal substrate 2 is larger than the thickness j of the stopper portion 3 in the free state shown in FIG. effective. That is, as shown in FIG. 5, when tightened between the cylinder head 21 and the cylinder block 22, the stopper portion 3 literally becomes a stopper and the bead portion 5 does not have a complete flat plate shape, Maintains resilience. Thereby, the bead part 5 is compressed by a value obtained by subtracting the thickness of the stopper part 3 from the raised thickness, that is, the tightening allowance h, and the cylinder head 21 and the cylinder block 22 are connected to each other by the stopper part 3 and the bead part 5. The cylinder head 1 is more strongly pressed and contacted to obtain a good sealing performance.

  In addition, when pressure P due to explosion combustion in the cylinder bore H acts, the cylinder head 21, that is, its bottom surface 21 a is instantaneously applied to the cylinder block 2 due to deformation of the cylinder head 21 or extension of the fastening bolt. Although it floats about 10 μm (0.01 mm) (see the phantom line in FIG. 5), there is sufficient elastic restoring force due to the presence of the tightening allowance h of the bead portion 5, and the floated bottom surface 21 a of the cylinder head 21 The bead portion 5 follows and can maintain a good sealing function.

  As an example of the dimensional relationship with the bead part 5, the thickness of the stopper part 3 is 0.01 to 0.5 mm, and the interference h of the bead part 5 is 0.1 to 0.6 mm (preferably 0.2 to 0.3 mm). If the cylinder head 21 is tightened and fixed to the cylinder block 2 (the state shown in FIG. 5) and the cylinder head 21 is lifted by 0.01 mm by the explosion force P, the tightening margin is 0.09 to 0.59 mm (preferably 0.19 to 0.29 mm) is present. Therefore, even if the cylinder head 21 is lifted, a good sealing function by the bead portion 5 is maintained.

  In the cylinder head gasket according to the second embodiment, as shown in FIGS. 6 and 7, the thickness of the annular stopper portion 3 provided in the peripheral portion of the bore hole 2a is changed in the circumferential direction as necessary. It is a thing. Specifically, the thickness of the stopper 3 is thin (d1) in the vicinity of the bolt hole 2b through which the bolt 23 for fastening the cylinder head 21 to the cylinder block 22 and assembling with the gasket 1 is inserted (d1). Between 2b, it is changed gently so that it becomes thick (d2).

  In other words, when the bolt 23 is tightened to assemble the cylinder head 21 to the cylinder block 22, the insertion portion of the bolt 23 in the cylinder head 21 is strongly compressed, but the compression force becomes weaker as the distance from the bolt 23 increases. After the tightening, as shown in FIG. 7, the cylinder head 21 is bent and deformed in a wave shape. As a result, the vertical gap between the cylinder head 21 and the cylinder block 22 also changes in the same manner. Therefore, the thickness of the cylinder head gasket 1, that is, the stopper portion 3 is changed in advance in anticipation of the deformation.

  As a result, the stopper part 3 (the cylinder head gasket 1) can be compressed almost uniformly in any part in the circumferential direction, and the airtightness of the intermediate part of the adjacent bolts 23 is not deteriorated. It becomes possible to obtain uniform and good sealing properties. In FIG. 7, the deformation of the cylinder head 21 and the like is exaggerated from the actual viewpoint for understanding the drawing.

  As a means for producing the above-described effects, the thickness of the stopper portion 3 remains constant, and its width dimension (radial width) is narrow in the vicinity of the bolt hole 2b and wide between the adjacent bolt holes 2b. You may change as you do. Further, a means for taking both the width change and the above-described thickness change may be used. Furthermore, due to the presence of the stopper portion 3, when tightening with the bolt 23, the thickness of the stopper portion 3 is increased in anticipation that the cylinder head 21 is deformed so that the gap with the cylinder block 22 increases as it approaches the bore hole 2 a. You may change so that it may become thick toward the inner peripheral side (bore hole 2a side).

Plan view of cylinder head gasket (Example 1) Aa line sectional view of FIG. Expanded cross section near the bore stopper Partial sectional view showing dimensional relationship between stopper and bead Partial sectional view showing the state of the bead portion when tightened and fixed A perspective view of a cylinder head gasket divided by a bore hole (Example 2) The figure which shows the arrow Y in FIG. Sectional view showing the structure of a conventional bore stopper Sectional view showing the structure of a conventional bore stopper Sectional view showing the structure of a conventional bore stopper Sectional view showing the structure of a conventional bore stopper

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Cylinder head gasket 2 Metal substrate 2a Bore hole 2b Bolt hole 3,7 Stopper part 4 Coating layer 5 Bead part H Through hole

Claims (6)

A cylinder head gasket comprising a metal substrate and an annular stopper formed in the periphery of a through-hole formed in the metal substrate,
The stopper portion is a cylinder head gasket formed by shot coating of metal powder on the metal substrate. In claim 1,
The cylinder head gasket, wherein the through hole is a bore hole formed corresponding to the cylinder bore. In claim 1 or 2,
A cylinder head gasket in which a bead portion that is annular and protrudes in the thickness direction of the gasket is formed on an outer peripheral portion of the stopper portion in the metal substrate. In any one of Claims 1-3,
The cylinder head gasket, wherein the metal powder is a powder made of an aluminum material. In any one of Claims 1-4,
A cylinder head gasket in which a coating layer of a rubber material is formed on an outer surface of the metal substrate and an outer surface of the stopper portion. In any one of Claims 1-5,
A cylinder head gasket in which the thickness of the stopper portion is changed in the circumferential direction as necessary.

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