gasket

Abstract

Provided is a gasket that ensures microscopic sealing and sliding properties even when holes having different functions are formed. In a gasket (1) in which a sealing target hole (3) and a fastening hole (4) are formed in a metal plate portion (2) and a coating (10) is applied to the surface of the metal plate portion (2), as the coating (10), there are a rubber layer (12) and a lubricating layer (13), and in the coating (10) of at least the portion of the surface of the metal plate portion (2) including the peripheral edge portion of the sealing target hole (3), the rubber layer (12) and the lubricating layer (13) are stacked, and the lubricating layer (13) is disposed on the surface layer, and in the coating (10) of the peripheral edge portion of the fastening hole (4), the rubber layer (12) is stacked, and the rubber layer (12) is disposed on the surface layer.

Description

Technical Field

[0001] The present invention relates to a gasket, and more particularly to a gasket having a microscopic sealing coating on a metal plate. Background Art

[0002] Various gaskets with coatings applied to the surface of metal plates have been proposed (see Patent Documents 1 to 3). The coating proposed in Patent Document 1 is a single-layer structure of a rubber coating layer containing inorganic lubricant powder that is insoluble in the solvent of the rubber coating, and is provided over the periphery of the combustion chamber hole or the entire surface of the metal plate. The coating proposed in Patent Document 2 is a single-layer structure of a rubber mixture coating containing inorganic lubricant powder and silane coupling agent added to a coating made of fluororubber as a raw material, and is provided on and near a plate that surrounds and seals fluid holes such as cylinder holes. The coating proposed in Patent Document 3 is a double-layer structure formed by laminating an elastomer coated on a metal plate and a coating composition containing an anionic polyester urethane resin, a fixed lubricant, and a solvent, and the location of the coating is not particularly limited. As described above, the coatings proposed in Patent Documents 1 to 3 are coatings that combine a rubber layer and a lubricating layer in order to ensure the sliding properties of the gasket, which would be hindered if there were only a rubber layer.

[0003] In addition to the holes to be sealed (such as cylinder holes, water and oil holes, and holes in the exhaust flow path), gaskets for engines and exhaust are also provided with fastening holes for inserting fasteners such as bolts. When the peripheral portion of the fastening hole is also coated with a coating consisting of a rubber layer and a lubricating layer as proposed in Patent Documents 1 to 3, the position of the fastening hole may deviate due to the smooth sliding of the peripheral portion of the fastening hole. In addition, due to degradation over time, the components of the lubricating layer invade the fastening hole, which becomes the main cause of the loosening of the fastener. On the other hand, when the peripheral portion of the fastening hole is not coated, the sealing performance will be reduced due to the influence of damage, surface roughness, deformation, etc. on the surface of the metal plate. Even if a coating as proposed in Patent Documents 1 to 3 is applied to a gasket with multiple holes with different functions, it is impossible to achieve both microscopic sealing and sliding properties, and further improvement is needed.

[0004] Prior art literature

[0005] Patent Literature

[0006] Patent Document 1: Japanese Patent Application Laid-Open No. 2000-81140

[0007] Patent Document 2: Japanese Patent Application Laid-Open No. 2004-68886

[0008] Patent Document 3: Japanese Patent Application Laid-Open No. 2012-219183 Summary of the Invention

[0009] Problems to be solved by the invention

[0010] An object of the present invention is to provide a gasket that can ensure microscopic sealing and sliding properties even if holes with different functions are formed therein.

[0011] Technical solutions to problems

[0012] The gasket of the present invention for achieving the above-mentioned purpose is characterized in that a sealing hole and a fastening (fastening connection) hole are formed on a metal plate portion, and a coating is applied to the surface of the metal plate portion. The coating is characterized in that the coating comprises a rubber layer and a lubricating layer having a smaller friction coefficient than that of the surface of the metal plate portion. The coating at a portion of the surface of the metal plate portion at least including the peripheral portion of the sealing hole comprises a stack of the rubber layer and the lubricating layer, and the lubricating layer is arranged on the surface layer. The coating at a peripheral portion of the fastening hole comprises a stack of the rubber layer, and the rubber layer is arranged on the surface layer.

[0013] Effects of the Invention

[0014] According to the present invention, by layering the coating layer according to its function, the coating's function can be differentiated depending on the location. Specifically, a rubber layer is placed in areas requiring microscopic sealing, while a lubricating layer is laminated on the rubber layer in areas requiring both microscopic sealing and sliding properties. This ensures microscopic sealing and sliding properties even when a metal plate has holes for sealing and holes for fastening, each with different functions. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] Fig. 1 It is an explanatory diagram illustrating an embodiment of a gasket.

[0016] Fig. 2 It is an explanatory diagram illustrating a label portion of a gasket.

[0017] Description of Reference Numerals

[0018] 1 gasket;

[0019] 2 metal sheet parts;

[0020] 3. Seal the object hole;

[0021] 4 fastening holes;

[0022] 5 cover;

[0023] 6. Sealing part;

[0024] 10 coating;

[0025] 11 clinging layer;

[0026] 12 rubber layers;

[0027] 13 Lubricating layer. DETAILED DESCRIPTION

[0028] Hereinafter, the gasket of the present invention will be described based on the embodiment shown in the drawings. Figs. 1-2 Dimensions are changed to make the structure easier to understand and may not necessarily correspond to the ratios of actual products.

[0029] Fig. 1 The gasket 1 illustrated in the figure is a cylinder head gasket for an engine, interposed between a cylinder block and a cylinder head of a known engine. The gasket 1 has a metal plate portion 2 formed with a sealing hole 3, a fastening hole 4, and a cover portion 5. The number of sealing holes 3, fastening holes 4, and cover portions 5 formed in the metal plate portion 2 is not particularly limited; a large number of sealing holes, fastening holes, and cover portions may be formed depending on the intended use.

[0030] The metal plate portion 2 is composed of a single metal plate or a plurality of metal plates stacked in the Z direction. The metal or alloy constituting the metal plate can be any known metal or alloy, such as stainless steel, copper, or aluminum. When the metal plate portion 2 is composed of a stack of plates, each metal plate can be composed of a different metal or alloy. The number of stacked plates is not particularly limited, but is preferably three or more and six or less.

[0031] The sealing hole 3 is a hole that passes through the metal plate portion 2 in the Z direction and through which a gas such as fuel gas or a liquid such as water or oil flows. Examples of the sealing hole 3 include a cylinder hole, a water-oil hole, and an exhaust gas flow hole. A sealing portion 6 is formed on the peripheral edge of the sealing hole 3. The sealing portion 6 can use a known sealing structure. Examples of the sealing structure include a protrusion formed by bending the metal plate of the metal plate portion 2, a fold, a gasket (grommet) attached to the end of the metal plate, and a rubber ring.

[0032] The fastening hole 4 is a hole through which a fastener such as a bolt is inserted, among the holes extending through the metal plate portion 2 in the Z direction. A sealing portion may be formed around the periphery of the fastening hole 4, similar to the sealing target hole 3. However, if sealing of the fastening hole 4 is not necessary, a sealing portion is not required.

[0033] The cover portion 5 is a portion that blocks the flow path of liquids such as water and oil, and is partitioned and formed on the lower surface of the metal plate portion 2. The cover portion 5 is always exposed to these liquids. As an example of the cover portion 5, a portion that covers the water jacket formed on the outside of the cylinder hole of the cylinder block in the gasket of an engine assembled in an open-deck structure is exemplified. In addition, the cover portion 5 is not limited to a portion that is always exposed to a moving fluid (a fluid flowing in a predetermined direction), but may also include a portion that is always exposed to a stationary fluid. In addition, the cover portion 5 is not limited to the lower surface of the metal plate portion 2, but may also include a cover portion that is partitioned and formed on the upper surface. The cover portion 5 that is partitioned and formed on the upper surface functions as a bottom of the flow path of the fluid, etc.

[0034] The coating 10 is applied (implemented) to at least the upper and lower surfaces of the metal plate portion 2 in the Z direction. In the case where the gasket 1 is composed of laminated plates, the coating 10 can also be applied to all surfaces of the upper and lower surfaces of each metal plate. The coating 10 can also be applied to the cover portion 5, but there is a possibility that the coating 10 will peel off due to being applied to the cover portion 5 that is constantly exposed to the fluid. Therefore, the coating 10 is preferably omitted from the cover portion 5 and applied to the upper and lower surfaces of the metal plate portion 2 other than the cover portion 5. By being applied to the surface of the metal plate portion 2, the coating 10 can eliminate the effects of damage, surface roughness, deformation, etc. on the surface of the metal plate, thereby improving the sealing performance of the gasket 1. The improvement in the sealing performance of the gasket 1 brought about by the coating 10 is micro-sealing. Although the micro-sealing performance may be high or low depending on the type of layer constituting the coating 10, even if the type of the constituting layer is different, the micro-sealing performance can be ensured compared to the surface of the metal plate to which the coating 10 is not applied.

[0035] The coating layer 10 includes a close contact layer 11, a rubber layer 12, and a lubricating layer 13. In the coating layer 10, each layer performs functions other than microscopic sealing, and the number of layers stacked differs depending on the location of the gasket 1.

[0036] The adhesion layer 11 is interposed between the surface of the metal plate portion 2 and the rubber layer 12. The adhesion layer 11 has the function of making the rubber layer 12 adhere closely to the surface of the metal plate portion 2. As long as the adhesion layer 11 has a relatively high adhesion to the surface of the metal plate portion 2 and the rubber layer 12, a known adhesive such as a water-based adhesive, an organic solvent-based adhesive, or an inorganic adhesive can be used. Depending on the circumstances, the adhesion layer 11 may be mixed with a known adhesive containing the same material as the rubber layer 12 (described later), but preferably has only the function of making the rubber layer 12 adhere closely to the surface of the metal plate portion 2. The adhesion layer 11 of this embodiment is composed of, for example, an epoxy resin.

[0037] The rubber layer 12 has a lower thermal conductivity than the metal plate, in addition to the function of further improving the adhesiveness of the metal plate portion 2. In addition, the rubber layer 12 has superior heat resistance to the adhesion layer 11, and has a higher heat resistance temperature than the adhesion layer 11. The heat resistance temperature is the temperature at which softening, a decrease in mechanical properties, deformation, adhesion to the surroundings, and the like occur, and is also referred to as a use limit temperature, a maximum use temperature, and the like. The rubber layer 12 can use a publicly known rubber having superior heat resistance, as long as it has a lower thermal conductivity than the metal plate and superior heat resistance to the adhesion layer 11. As the rubber having superior heat resistance, synthetic rubbers such as fluorine rubber and silicone rubber are exemplified. The rubber layer 12 of the present embodiment is composed of fluorine rubber, for example.

[0038] In the present embodiment, the adhesion layer 11 and the rubber layer 12 are provided as separate layers, but if the rubber layer 12 sufficiently adheres to the surface of the metal plate portion 2, the adhesion layer 11 is not necessarily provided. In addition, instead of the adhesion layer 11 and the rubber layer 12, an adhesion rubber layer in which an adhesive of the same kind as the adhesive that constitutes the adhesion layer 11 is mixed in the rubber layer 12 can be used. However, in the adhesion rubber layer, the ratio of each of the rubber component and the adhesive component per unit volume is low, and the functions achieved by the rubber and the adhesive are reduced compared to the configuration in which the adhesion layer 11 and the rubber layer 12 are provided as separate layers. Therefore, it is preferable that the adhesion layer 11 and the rubber layer 12 be provided as separate layers.

[0039] The lubricating layer 13 has superior lubricity to the surface of the metal plate portion 2, and has a smaller coefficient of friction than the surface of the metal plate. The lubricating layer 13 can use a publicly known solid lubricant, as long as it has superior lubricity to the surface of the metal plate portion 2. As the solid lubricant, fluorine resin, molybdenum disulfide, graphite, and the like are exemplified. The lubricating layer 13 can be composed of only the solid lubricant, but an adhesive can be used as a binder in order to improve the adhesiveness with the lower layer. The lubricating layer 13 of the present embodiment is composed of fluorine resin using an epoxy resin as a binder.

[0040] The coating layer 10 is composed of the adhesion layer 11, the rubber layer 12, and the lubricating layer 13 in the portion including the periphery of the seal target hole 3 of the seal portion 6. In detail, in the portion including the seal portion 6, the adhesion layer 11, the rubber layer 12, and the lubricating layer 13 are sequentially stacked from the surface of the metal plate portion 2, and the lubricating layer 13 is disposed on the surface layer of the coating layer 10. The portion including the seal portion 6 can be a portion including only the seal portion 6, but in order to improve the sealability of the gasket 1, it is preferable that the portion be a portion other than the periphery of the fastening hole 4 and the cover portion 5.

[0041] By applying a three-layer coating 10 to the area including the sealing portion 6, in addition to the macro-sealing function achieved by the coating 10, three functions are also achieved. The first function is to prevent peeling of the coating 10 by improving the adhesion brought about by the close-fitting layer 11. The second function is to prevent thermal damage to the close-fitting layer 11 by improving the heat resistance brought about by the rubber layer 12. In addition, along with this function, there is also a function of preventing thermal damage to the metal plate portion 2 by also suppressing heat transfer to the metal plate portion 2. The third function is to reduce the friction of the surface of the gasket 1 by improving the sliding properties brought about by the lubricating layer 13, thereby allowing smooth sliding.

[0042] In the area surrounding the fastening hole 4, the coating layer 10 is composed of two layers: a close-fitting layer 11 and a rubber layer 12. Specifically, the close-fitting layer 11 and the rubber layer 12 are stacked in this order around the fastening hole 4, starting from the surface of the metal plate portion 2, with the rubber layer 12 positioned on the surface of the coating layer 10.

[0043] By applying a two-layer coating 10 to the periphery of the fastening hole 4, the lubricating layer 13 present in the three-layer coating 10 is absent. This prevents the lubricating layer 13 from causing positional deviation of the fastening hole 4 and loosening of the fastener. Furthermore, in addition to providing microscopic sealing, the periphery of the fastening hole 4 also functions to prevent peeling of the coating 10 by improving adhesion due to the adhesion layer 11, and to prevent thermal damage to the adhesion layer 11 by improving heat resistance due to the rubber layer 12.

[0044] Next, the manufacturing method of the gasket 1 is described. After applying the coating 10 to the metal plate constituting the metal plate portion 2, the gasket 1 forms the sealing target hole 3, the fastening hole 4, and the sealing portion 6. The coating 10 is formed by repeatedly applying and drying a different coating for each layer. In detail, on the metal plate having the upper and lower surfaces of the metal plate portion 2, excluding the cover portion 5, a coating for a close-fitting layer composed of epoxy resin is applied and dried to form a close-fitting layer 11. Then, on the close-fitting layer 11, a coating for a rubber layer composed of fluororubber is applied and dried to form a rubber layer 12. Next, on the rubber layer 12, excluding the peripheral portion of the fastening hole 4, a coating for a lubricating layer composed of epoxy resin and fluororesin is applied and dried to form a lubricating layer 13.

[0045] Fig. 2The label portion 7 shown in the figure extends outward from the outer periphery of the metal plate portion 2 when viewed from above. The label portion 7 is a component that is not clamped between the upper and lower components when the gasket 1 is clamped between the upper and lower components and tightened. The label portion 7 preferably extends outward from the outer periphery of the upper and lower components. On the surface of the label portion 7, the coating 10 is exposed respectively. Specifically, on the surface of the label portion 7, the close-fitting layer 11, the rubber layer 12 and the lubricating layer 13 are exposed in sequence from one end of the Y direction to the other end. In the label portion 7, each layer is coated when the coating 10 is formed. By having such a label portion 7 and coating the label portion 7 when coating each layer, the stacking state of the coating 10 can be easily confirmed. Therefore, it is beneficial to prevent mistakes such as forgetting to coat during the manufacturing process.

[0046] In addition, it is preferred that the object colors of all layers, including the metal plate portion 2 and the layers of the coating 10, are different from each other so that they can be managed by color distinction. In the case where there is no difference in the object color of any of the layers, the paint can be mixed to make the hue, saturation, and brightness different. In this way, by making the object colors of all layers, including the metal plate portion 2 and the layers of the coating 10, different, the fastening holes 4, the cover portion 5, and other parts including the sealing portion 6 are easier to distinguish. In this way, the differences between the various parts of the gasket 1 become obvious, and it is easy to determine the direction of the gasket 1, such as the front and back. Therefore, it is beneficial to prevent errors when assembling the metal plate portion 2 or assembling the gasket 1 to the engine.

[0047] The thickness of each layer in the coating 10 may be equal or different. For example, by making the rubber layer 12 thicker than the other layers, durability can be improved. The thickness of each layer of the coating 10 is, for example, 5 μm to 15 μm.

[0048] As described above, according to this embodiment, by layering the coating layer 10 for each function, the function of the coating layer 10 can be varied depending on the location of the gasket 1. Specifically, the rubber layer 12 is disposed in locations requiring microscopic sealing, and the lubricating layer 13 is laminated on the rubber layer 12 in locations requiring sliding properties in addition to microscopic sealing properties. Therefore, even when the sealed hole 3 and the fastening hole 4 are formed in the metal plate, microscopic sealing properties and sliding properties can be ensured.

[0049] For example, in the coating layer of the prior art of the single layer construction, by mixing the rubber, the solid lubricant, and the adhesive respectively, the coating process is performed once, but the ratio of each unit area becomes low. That is, in the coating layer of the single layer construction, although the functions of the rubber, the solid lubricant, and the adhesive are exerted, the functions of each become low. On the other hand, according to the present embodiment, by layering the coating layer 10 by each function, although the process of forming each layer increases, the functions of each layer do not decrease. In addition, in the coating layer of the prior art of the single layer construction, due to the mixing of the plurality of components, the functions become uneven according to the site, and the yield rate also becomes low. On the other hand, according to the present embodiment, by layering the coating layer 10 by each function, it is difficult to cause the functions to become uneven according to the site, and it is possible to maintain the yield rate high.

[0050] The foregoing describes the embodiment of the present application, but the gasket of the present application is not limited to the specific embodiment, and various modifications and changes can be made within the scope of the gist of the present application.

[0051] The gasket of the present application is not limited to the cylinder head gasket, and can be applied to various gaskets known. For example, it can also be applied to the exhaust gasket used in the connection of the exhaust pipes to each other, the manifold gasket.

[0052] The gasket of the present application makes the functions of the coating layer 10 different according to the site, but in the case where the sites overlap each other, the disadvantages of the coating layer 10 can be given priority. For example, in the case where the peripheral site of the sealing object hole 3 and the peripheral site of the fastening hole 4 overlap, in the overlapping site, the coating layer 10 of two layers (the close layer 11, the rubber layer 12) can be applied instead of the coating layer 10 of three layers.

Claims

1. A gasket having a sealed hole and a fastening hole formed in a metal plate portion, wherein a coating is applied to the surface of the metal plate portion, characterized in that: The coating layer includes a rubber layer and a lubricating layer with a lower friction coefficient than the surface of the metal plate portion. In the coating layer on the surface of the metal plate portion, at least including the peripheral portion of the sealing target hole, the rubber layer and the lubricating layer are stacked, and the lubricating layer is arranged on the surface layer. In the coating layer on the peripheral portion of the fastening hole, the rubber layer is stacked, and the rubber layer is arranged on the surface layer.

2. The gasket according to claim 1, A cover portion that is always exposed to liquid is formed on the surface of the metal plate portion. The coating layer is omitted from the cover portion to expose the surface of the metal plate portion.

3. The gasket according to claim 1, The coating layer includes an adhesion layer interposed between the surface of the metal plate portion and the rubber layer.

4. The gasket according to claim 2, The coating layer includes an adhesion layer interposed between the surface of the metal plate portion and the rubber layer.

5. The gasket according to claim 4, The coating layer on the surface of the metal plate portion excluding the peripheral edge portion of the fastening hole and the cover portion comprises three layers, namely, the adhesion layer, the rubber layer, and the lubricating layer, stacked in this order from the surface of the metal plate portion.

6. The gasket according to any one of claims 1 to 5, The metal plate portion includes a label portion extending outward from an outer periphery in a plan view, and the coating layers are exposed on surfaces of the label portion.

7. The gasket according to any one of claims 1 to 5, All layers including the metal plate portion and the coating layer have different physical colors so that they can be managed by distinguishing by color.

8. The gasket according to claim 6, All layers including the metal plate portion and the coating layer have different physical colors so that they can be managed by distinguishing by color.

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