JP2013029117A - Gasket - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a gasket capable of improving heat radiation property without hindering sealing property.SOLUTION: The gasket 1 includes an inner plate 11 and a coating layer 12 formed on the surface (upper surface and lower surface) of the inner plate 11. An additive 13 (graphite) having a coefficient of thermal conductivity higher than the material (nitrile rubber) of the coating layer 12 is added to the inside the coating layer 12. The additive 13 has a spherical shape and the particle size d of the additive 13 is set to be the thickness t of the coating layer 12 or more. That is, the additive 13 is configured such that one edge thereof is exposed to the surface of the coating layer 12 and the other edge thereof is in contact with the surface of an inner plate 11.

Description

  The present invention relates to a gasket interposed between a pair of flanges arranged to face each other.

For example, there is a gasket described in Patent Document 1. The gasket described in Patent Document 1 is interposed between a cylinder block and a cylinder head of an internal combustion engine.
A sealing film made of resin is provided on the surface of the gasket core plate. The sealing film is deformed according to microscopic irregularities present on the mating surfaces of the cylinder block and the cylinder head, and the gap between these mating surfaces and the gasket is filled, so that the sealing performance is maintained.

Japanese Utility Model Publication No. 1-60074

  However, such a sealing film is formed of a material having a lower thermal conductivity (for example, a resin such as nitrile rubber) than the core plate. Therefore, the presence of such a sealing film makes it difficult for the heat of the cylinder block to be transmitted to the cylinder head, and this is one factor that particularly increases the temperature of the cylinder bore. As a result, there may be a problem that the oil consumption increases and a problem that the durability of the cylinder bore wall decreases. In addition, since the temperature between the cylinder bores, where the combustion heat tends to concentrate, increases, there is a possibility that the friction when the piston reciprocates increases when the cylinder bore is thermally deformed.

  On the other hand, for example, instead of a resin sealing film, a sheet made of graphite having high thermal conductivity may be bonded to the surface of the core plate. However, there is a problem that graphite is easily peeled off from the gasket surface and the sealing performance is impaired.

  Such a problem is not limited to the gasket of the internal combustion engine, but can be caused in general if the gasket is interposed between a pair of flanges arranged to face each other.

  This invention is made | formed in view of such a situation, The objective is to provide the gasket which can improve heat dissipation, without impairing sealing performance.

Hereinafter, means for solving the above-described problems and the effects thereof will be described.
The invention according to claim 1 is a gasket interposed between a pair of flanges arranged to face each other, and includes a core plate and a seal film formed on the surface of the core plate. An additive having a higher thermal conductivity than the material of the seal film is added inside the seal film, and one end of the additive is exposed on the surface of the seal film and the other end of the core plate. Its gist is that it is in contact with the surface.

  According to this configuration, when the gasket is assembled between the pair of flanges, one end of the additive material comes into contact with the flange surface and the other end comes into contact with the core plate surface of the gasket. For this reason, the heat transfer between the flange surface and the core plate of the gasket is directly performed by the additive having a higher thermal conductivity than the material of the seal film. Therefore, the heat dissipation of the gasket can be improved without impairing the sealing performance.

  According to a second aspect of the present invention, in the gasket according to the first aspect, the additive material has a substantially granular shape, and the particle size of the additive material is equal to or greater than the thickness of the seal film. This is the gist.

  When the additive is substantially granular, as in the above configuration, if the additive has a particle size equal to or greater than the thickness of the seal film, one end of the additive is exposed on the surface of the seal film and the other end The invention according to claim 1 can be easily realized by contacting the surface of the core plate.

  Incidentally, when an additive whose particle size is extremely smaller than the thickness of the seal film is added, the heat dissipation of the entire seal film is enhanced to some extent by adding the additive having high thermal conductivity. . However, when heat is transferred in the film thickness direction, it becomes a structure that alternately passes a sealing material with a low thermal conductivity and an additive with a high thermal conductivity, so when trying to further improve the heat dissipation as a whole gasket Naturally there is a limit.

  According to a third aspect of the present invention, in the gasket according to the first or second aspect, the additive is made of a material having a lower hardness than the pair of flanges and the core plate, and between the pair of flanges. The gist is that the gasket can be deformed in a state where the gasket is assembled.

  According to this configuration, when the gasket is assembled between the pair of flanges, the additive material is deformed by receiving a compressive load by the core plate and the flange of the gasket. For this reason, it can suppress that a gap | interval arises by arrange | positioning an additive between a flange and a gasket. Moreover, since the hardness of the additive is lower than that of the pair of flanges and the core plate, the flange and the core plate are not deformed by the additive. Accordingly, it is possible to maintain good sealing performance between the flange and the gasket.

The gist of the invention of claim 4 is that, in the gasket of claim 3, the additive is made of graphite.
Since graphite has a high thermal conductivity and is a material that easily deforms against a compressive load, the invention according to claim 3 can be suitably embodied.

  The gist of the invention according to claim 5 is that, in the gasket according to any one of claims 1 to 4, the pair of flanges are a cylinder head and a cylinder block of an internal combustion engine. .

According to the configuration, the movement of heat between the cylinder block and the cylinder head can be preferably promoted through the gasket.
According to a sixth aspect of the present invention, in the gasket according to the fifth aspect, the internal combustion engine is a multi-cylinder internal combustion engine having a plurality of cylinders, and the additive material is added only to a portion corresponding to between the cylinder bores in the gasket. It is the gist of what has been done.

  In a multi-cylinder internal combustion engine having a plurality of cylinders, the temperature between the cylinder bores, where the combustion heat tends to concentrate, tends to increase. Therefore, when an additive is added to the entire gasket surface, the heat dissipation of the gasket can be enhanced over the entire surface, but the part corresponding to the space between the cylinder bores will remain at a higher temperature than other parts. The temperature difference between these parts may not be reduced.

  In this respect, according to the above configuration, since the additive material is added only to the portion corresponding to the space between the cylinder bores in the gasket, the heat dissipation of the portion can be improved and the temperature rise between the cylinder bores can be suitably suppressed. . In addition, since no additive is added to any part other than the part, the temperature difference between the parts can be suitably reduced.

The top view which shows the planar structure of a cylinder head gasket about one Embodiment of this invention. Sectional drawing which shows the cross-section of a cylinder head gasket. It is sectional drawing which shows typically the cross-sectional structure centering on the cylinder head gasket of the embodiment, Comprising: (a) Sectional drawing which shows the state in which compression load is not acting on a gasket, (b) Compression load is applied to a gasket. Sectional drawing which shows the state which is acting.

  1 to 3, an embodiment in which the gasket according to the present invention is embodied as a cylinder head gasket of an in-line four-cylinder gasoline engine (hereinafter simply referred to as gasket 1) will be described in detail.

As shown in FIG. 1, the gasket 1 is formed with four cylinder bores 1a corresponding to the four cylinder bores of the engine.
As shown in FIG. 2, the gasket 1 includes an inner plate 11 made of stainless steel, and a coating layer 12 made of nitrile rubber that is applied to both surfaces of the inner plate 11. Here, the thickness of the inner plate 11 is 200 μm, whereas the thickness t of the coating layer 12 on one side is 25 μm.

  Further, in particular, in the portion indicated by oblique lines in FIG. 1, that is, the addition portion 1c corresponding to the space between the cylinder bores at the hole edge 1b of the gasket 1, as shown in FIGS. An additive 13 having a thermal conductivity λf higher than the thermal conductivity λc of the material of the coating layer 12 (nitrile rubber) is added inside. This additive 13 is spherical graphite (graphite), and has a lower hardness than the cylinder block 30 and the cylinder head 40 (both are aluminum alloys).

  As shown in FIG. 3A, the particle size d of the additive 13 is not less than the thickness t of the coating layer 12 (d ≧ t) in a state in which no compressive load is applied to the gasket 1. Specifically, the particle size d of the additive 13 is 25 to 30 μm, and is about 1.0 to 1.2 times the thickness t (25 μm) of the coating layer 12.

  As the amount of the additive 13 added to the coating layer 12 is increased, the heat dissipation of the gasket 1 as a whole is enhanced. However, it is an invention that even if graphite (additive 13) of 15% or more by weight is added to the nitrile rubber (coating layer 12) in the paste state, the heat dissipation as the gasket 1 does not increase any more. Has been confirmed through experimentation. Therefore, the gasket 1 of this embodiment employs a material in which 15% by weight of the additive 13 is added to the coating layer 12 in the paste state.

Next, the operation of this embodiment will be described.
When the gasket 1 is assembled between the upper surface 31 of the cylinder block 30 and the lower surface 41 of the cylinder head 40, the gasket 1 receives a compressive load from the cylinder block 30 and the cylinder head 40. In this case, as shown in FIG. 3B, the additive 13 is plastically deformed by receiving the compression load. Thereby, in the coating layer 12 on the cylinder block 30 side, the lower end of the additive 13 comes into contact with the upper surface 31 of the cylinder block 30 and the upper end comes into contact with the lower surface of the inner plate 11. Further, in the coating layer 12 on the cylinder head 40 side, the upper end of the additive 13 contacts the lower surface 41 of the cylinder head 40 and the lower end contacts the upper surface of the inner plate 11. For this reason, heat transfer between the upper surface 31 of the cylinder block 30 and the lower surface of the inner plate 11 of the gasket 1 and heat transfer between the upper surface of the inner plate 11 and the lower surface 41 of the cylinder head 40 are added. This is done directly by the material 13.

According to the gasket which concerns on this embodiment demonstrated above, the effect shown below comes to be acquired.
(1) The gasket 1 has an inner plate 11 and a coating layer 12 formed on the surface (upper surface and lower surface) of the inner plate 11. An additive 13 having a higher thermal conductivity than the material of the coating layer 12 (nitrile rubber) is added inside the coating layer 12. The additive 13 has a spherical shape, and the particle size d of the additive 13 is greater than or equal to the thickness t of the coating layer 12. That is, one end of the additive 13 is exposed on the surface of the coating layer 12 and the other end is in contact with the surface of the inner plate 11.

  According to such a configuration, the heat dissipation performance of the gasket 1 can be improved without impairing the sealing performance, and the heat of the cylinder block 30 can be quickly transmitted to the cylinder head 40 through the gasket 1.

(2) The additive 13 is made of graphite, which is a material having lower hardness than the cylinder block 30 and the cylinder head 40 (both are aluminum alloys).
According to such a configuration, there is a gap due to the additive material 13 being disposed between the upper surface 31 of the cylinder block 30 and the lower surface of the gasket 1 and between the lower surface 41 of the cylinder head 40 and the upper surface of the gasket 1. It is possible to suppress the occurrence. Further, since the additive material 13 has a lower hardness than the cylinder block 30, the cylinder head 40, and the inner plate 11, the upper surface 31 of the cylinder block 30 and the lower surface 41 of the cylinder head 40 are not deformed by the additive material 13. Therefore, the sealing performance between the cylinder block 30 or the cylinder head 40 and the gasket 1 can be maintained well.

(3) The additive 13 is added only to the addition site 1c corresponding to the space between the cylinder bores in the gasket 1.
In a multi-cylinder internal combustion engine, the temperature between cylinder bores, where combustion heat tends to concentrate, tends to increase. Therefore, when an additive is added to the entire gasket surface, the heat dissipation of the gasket can be enhanced over the entire surface, but the part corresponding to the space between the cylinder bores will remain at a higher temperature than other parts. The temperature difference between these parts may not be reduced.

  In this regard, according to the above-described embodiment, since the additive 13 is added only to the addition site 1c corresponding to the space between the cylinder bores in the gasket 1, the heat dissipation of the addition site 1c is enhanced to increase the temperature between the cylinder bores. It can suppress suitably. Moreover, since the additive 13 is not added to parts other than the addition part 1c, the temperature difference between the parts can be suitably reduced.

In addition, the gasket which concerns on this invention is not limited to the structure illustrated in the said embodiment, For example, it can also implement as the following forms which changed this suitably.
In the above embodiment, the cylinder block 30 and the cylinder head 40 made of aluminum alloy are exemplified, but the cylinder block and the cylinder head may be made of cast iron.

  In the above embodiment, 15% of the additive 13 is added to the coating layer 12 by weight. However, the addition ratio of the additive according to the present invention is not limited to the above ratio. Since a preferable addition ratio of the additive varies depending on the material of the coating layer (seal film) and the material of the additive, it is desirable to appropriately set the heat dissipation required for the gasket.

  In the above-described embodiment, the gasket 1 in which the additive 13 is added only to the addition site 1c corresponding to the cylinder bore, in other words, the gasket 1 in which the additive 13 is not added to the site other than the addition site 1c is illustrated. Alternatively, the additive material distribution may be set such that the additive material is added to the entire surface of the gasket, while the concentration of the additive material decreases as the distance from the corresponding portion between the cylinder bores increases. According to such a gasket, since the concentration of the additive is lowered as the temperature of the gasket is lower, the temperature difference between the respective portions of the gasket can be accurately reduced. In addition, when the temperature rise between the cylinder bores is not a problem, the additive concentration of the additive may be set uniformly over the entire surface of the gasket. In this case, the sealing film and the additive can be easily formed on the gasket.

  In the above embodiment, the gasket 1 is constituted by the inner plate 11 and the coating layer 12 formed on both surfaces (upper surface and lower surface) thereof. However, the gasket according to the present invention is not limited to the one using only one gasket 1 as described above, and a plurality of such gaskets can be laminated and used. In this case, it is desirable to interpose a plate material having a high thermal conductivity (for example, a metal plate such as stainless steel) between the gaskets.

  -The gasket which concerns on this invention is not limited to the cylinder head gasket of a gasoline engine. In addition, the present invention can be applied to, for example, a cylinder head gasket of a diesel engine. The gasket according to the present invention is not limited to the cylinder head gasket. In short, the present invention can be applied to any gasket as long as it is interposed between a pair of flanges.

  In the above embodiment, the coating layer 12 is illustrated as being formed of nitrile rubber. However, the material of the sealing film according to the present invention is not limited to this. That is, a resin material containing another rubber material can be employed.

  -In the said embodiment, although illustrated about the additive which consists of graphite, the material of an additive is not limited to this. In short, any material having a higher thermal conductivity than the material of the sealing film may be used. For example, when the seal film is a resin material, a carbon allotrope (for example, diamond), a metal material (for example, copper or aluminum), a ceramic material (for example, aluminum oxide), or the like may be employed.

  -The shape of an additive is not restricted to the spherical shape (granular shape) illustrated in the said embodiment. For example, flake graphite can be used for graphite. Also in this case, it is sufficient that one end of the additive is exposed on the surface of the sealing film and the other end is in contact with the surface of the core plate.

  DESCRIPTION OF SYMBOLS 1 ... Gasket, 1a ... Hole for cylinder bores, 1b ... Hole edge part, 1c ... Addition part, 11 ... Inner plate (core board), 12 ... Coating layer (sealing film), 13 ... Additive material, 30 ... Cylinder block, 31 ... upper surface, 40 ... cylinder head, 41 ... lower surface.

Claims (6)

In a gasket interposed between a pair of flanges arranged to face each other, having a core plate and a seal film formed on the surface of the core plate,
An additive having a higher thermal conductivity than the material of the seal film is added inside the seal film, and one end of the additive is exposed on the surface of the seal film and the other end of the core plate. A gasket characterized by being in contact with the surface. The gasket according to claim 1,
The additive is substantially granular,
The gasket according to claim 1, wherein a particle diameter of the additive is equal to or greater than a thickness of the seal film. The gasket according to claim 1 or 2,
The additive material is made of a material having a lower hardness than the pair of flanges and the core plate, and is deformable in a state where the gasket is assembled between the pair of flanges. The gasket according to claim 3,
The gasket, wherein the additive is made of graphite. In the gasket according to any one of claims 1 to 4,
A gasket characterized in that the pair of flanges are formed as a cylinder head and a cylinder block of an internal combustion engine. The gasket according to claim 5,
The internal combustion engine is a multi-cylinder internal combustion engine having a plurality of cylinders;
The gasket is characterized in that the additive material is added only to a portion corresponding to between the cylinder bores in the gasket.

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