JP2005180552A - Metal gasket for cylinder head - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To optimize a rubber coating layer by the peripheral part and outer part of a cylinder hole. <P>SOLUTION: In a metal gasket for a cylinder head, which is made of a metallic plate and includes at least one base plate 2 in which a rubber coating layer is laid on at least the outward surface, at least one base plate includes: a cylinder hole peripheral part 2e having an annular bead 2b; and an outward part 2f having an outer peripheral bead 2d outside of the cylinder hole peripheral part 2e and formed separately from the cylinder hole peripheral part 2e, a rubber coating layer 2g laid on the surface of the metallic plate of the cylinder hole peripheral part 2e and a rubber coating layer 2h laid on the surface of the metallic plate of the outward part 2f are different, and the cylinder hole peripheral part 2e and the outward part 2f are connected to each other by a connecting means 5 in a position corresponding to the cooling water jacket. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a cylinder head metal gasket inserted between a cylinder block and a cylinder head of an internal combustion engine.

  As this type of metal gasket, for example, a cylinder hole formed corresponding to each cylinder bore of a cylinder block of an internal combustion engine, an annular bead having an angled cross section formed around each cylinder hole, and the cylinder block A cooling water hole formed in the outer peripheral portion of each annular bead corresponding to the cooling water jacket of the cylinder head and the cooling water hole of the cylinder head, and a position surrounding the annular bead and the cooling water hole as a whole. And having at least one substrate having a rubber coating layer on at least an outward surface (a surface facing a cylinder block and a cylinder head) and an outer peripheral bead having a single bevel-shaped cross section. Yes.

  In such a metal gasket, it is generally necessary to seal the periphery of the cylinder hole so that the high-temperature and high-pressure combustion gas in the cylinder bore of the cylinder block of the internal combustion engine does not leak outside, while the periphery of the cylinder hole The outer portion needs to be sealed so that the cooling water in the cooling water jacket of the cylinder block does not leak to the outside. Therefore, by providing a step structure that makes the periphery of the cylinder hole thicker than the outer part outside it, the surface pressure applied to the annular bead of the substrate is increased, improving the sealing performance against the combustion gas in the cylinder hole There is a case to let you.

  Conventionally, as the above-mentioned step structure, as shown in FIG. 10, for example, an annular bead 2b around each cylinder hole 2a of the substrate 2 is provided between two substrates 2 made of steel plates each having a rubber coating layer laid on both sides. There is known a step structure S1 in which a sub-plate 3 made of a thin steel plate is inserted so as to overlap a cylinder hole peripheral portion 2e having a predetermined step (see, for example, Patent Document 1). In the figure, reference numeral 1 denotes a metal gasket. In the metal gasket 1 of this example, two substrates 2 and a sub-plate 3 between them are joined by shear extrusion (so-called lance lock) formed by press molding. The parts 5 are connected to each other.

  Further, as the above-described step structure, as shown in FIG. 11, for example, it is overlapped on one substrate 2 having a rubber coating layer laid on both sides, and this is also another sheet having a rubber coating layer laid on both sides. The substrate 2 (the lower substrate in the figure) 2 overlaps the cylinder hole periphery 2e having the annular bead 2b around each cylinder hole 2a of the previous substrate 2 and this also has the cylinder hole periphery 2e having the annular bead 2b and It is composed of thin steel plates with different thicknesses on the outer part 2f located on the outer side so as to form a required step, and the projecting sides of the annular beads 2b are opposed to each other, and the cylinder of the latter substrate 2 There is also known a step structure S2 in which the hole peripheral portion 2e and the outer portion 2f are butted and coupled by laser welding (see, for example, Patent Document 2). In addition, the code | symbol LW in a figure shows a laser welding part.

Further, as the above-described stepped structure, conventionally, as shown in FIG. 12, for example, the substrate of the sub-plate 3 made of a thin steel plate interposed between the two substrates 2 made of steel plate each having a rubber coating layer laid on both sides. The shim plate 4 made of a thin steel plate is overlapped with the cylinder hole peripheral portion 3a that overlaps the cylinder hole peripheral portion 2e having the annular bead 2b around each cylinder hole 2a, so that the sub-plates have the required steps. A step structure S3 in which 3 and a shim plate 4 are joined by laser welding is also known (see, for example, Patent Document 2).
Japanese Patent Laid-Open No. 10-281288, FIG. Japanese Patent Laid-Open No. 7-243531, FIG. 4, FIG.

  However, in the conventional metal gasket, as described above, it is necessary to seal the peripheral portion of the cylinder hole so that the high-temperature and high-pressure combustion gas in the cylinder bore does not leak to the outside. The part outside the peripheral part needs to be sealed so that the cooling water in the cooling water jacket of the cylinder block does not leak to the outside. Usually, each substrate 2 is composed of a single metal plate and is a rubber. Since the coating layer is laid on the metal plate before the substrate is cut out, the coating layer has a uniform and uniform thickness over the entire substrate 2.

  Therefore, if the rubber coating layer has excellent heat resistance so as to be suitable for sealing the combustion gas around the cylinder hole, or if it is thin or hard to withstand the high surface pressure of the annular bead, Sealing of the cooling water at the part is not always sufficient. On the other hand, the rubber coating layer should be excellent in cooling water resistance so as to be suitable for sealing of the cooling water at the outer part, or sealed even at a low surface pressure of the outer peripheral bead. If it is made thicker or softer, the combustion gas is not necessarily sealed around the periphery of the cylinder hole.

  An object of the present invention is to advantageously solve the above-mentioned problems. A cylinder head metal gasket according to the present invention is made of a metal plate and is formed corresponding to each cylinder bore of a cylinder block of an internal combustion engine. Cylinder holes, an annular bead having a chevron-shaped cross section formed around each cylinder hole, and an outer peripheral portion of each annular bead corresponding to the cooling water jacket of the cylinder block and the cooling water hole of the cylinder head. A cooling water hole formed, and an outer peripheral bead having a single bevel-shaped cross section formed at a position surrounding the annular bead and the cooling water hole, and a rubber coating layer is laid at least on the outward surface In a cylinder head metal gasket comprising at least one substrate formed, at least one of the substrates. And a cylinder hole peripheral part having the annular bead and an outer part having the outer peripheral bead outside the cylinder hole peripheral part and formed separately from the cylinder hole peripheral part. The rubber coating layer laid on the surface of the metal plate around the hole is different from the rubber coating layer laid on the surface of the outer metal plate, and the cylinder hole peripheral portion and the outer portion are different from each other. The coupling means is coupled at a position corresponding to the cooling water jacket.

  In such a metal gasket for a cylinder head according to the present invention, an annular bead having an angled cross section around a cylinder hole formed corresponding to each cylinder bore of a cylinder block of an internal combustion engine has a high temperature and high pressure inside the cylinder bore. While sealing so that the combustion gas does not leak to the outside, the outer peripheral bead outside the periphery of the cylinder hole seals the cooling water in the cooling water jacket of the cylinder block from leaking outside. .

  In the cylinder head metal gasket according to the present invention, at least one of the substrates has a cylinder hole peripheral portion having an annular bead and an outer peripheral bead outside the cylinder hole peripheral portion, and separately from the cylinder hole peripheral portion. The rubber coating layer laid on the surface of the metal plate around the cylinder hole is different from the rubber coating layer laid on the surface of the metal plate on the outer side. Since the cylinder hole peripheral part and the outer part are connected by the connecting means at a position corresponding to the cooling water jacket of the cylinder block of the internal combustion engine, the rubber coating layer around the cylinder hole is suitable for sealing the combustion gas. At the same time as making it excellent in heat resistance or making it thin or hard to withstand the high surface pressure of the annular bead It is possible to make the outer rubber coating layer excellent in cooling water resistance so as to be suitable for sealing of cooling water, and to be thick or soft so as to seal even with a low surface pressure of the outer peripheral bead, The peripheral part of the cylinder hole and the outer part are integrally connected by a connecting part that escapes to the cooling water jacket so as not to prevent the tightening of the cylinder head to form a predetermined gasket shape.

  Therefore, according to the metal gasket for a cylinder head of the present invention, the cooling water in the cooling water jacket in the outer part outside the peripheral part of the cylinder hole is sufficiently sealed while the combustion gas is sufficiently sealed in the peripheral part of the cylinder hole. Sealing can be sufficiently performed, and the sealing performance of the metal gasket can be improved as a whole.

  In the cylinder head metal gasket according to the present invention, preferably, the metal plate around the cylinder hole is thicker than the metal plate at the outer portion. In this way, a step structure that increases the surface pressure of the annular bead can be easily configured.

  In the cylinder head metal gasket according to the present invention, the metal plate around the cylinder hole is preferably harder than the metal plate at the outer portion. In this way, the surface pressure of the annular bead can be increased without the step structure, and the surface pressure can be further increased by providing the step structure.

  Furthermore, in the metal gasket for a cylinder head according to the present invention, the rubber coating layer laid on the surface of the metal plate around the cylinder hole is preferably excellent in heat resistance, and the surface of the outer metal plate The rubber coating layer laid on is made to have excellent cooling water resistance. In this way, while the combustion gas sealing at the periphery of the cylinder hole is sufficiently performed with the rubber coating layer having excellent heat resistance, the inside of the cooling water jacket at the outer part outside the periphery of the cylinder hole is provided. Cooling water can be sufficiently sealed with a rubber coating layer excellent in cooling water resistance, and the sealing performance of the metal gasket can be improved as a whole.

  Further, in the cylinder head metal gasket according to the present invention, preferably, a rubber coating layer laid on the surface of the outer metal plate is a rubber coating layer laid on the surface of the metal plate around the cylinder hole. It is assumed to be thicker. In this way, the sealing of the combustion gas at the periphery of the cylinder hole is relatively thin compared to the outer part, so the rubber coating layer that increases the surface pressure of the annular bead is sufficiently performed while the outer part is sealed. The cooling water in the cooling water jacket can be sufficiently sealed with a rubber coating layer that seals even at low surface pressure because it is relatively thicker than the peripheral part, and the overall sealing performance of the metal gasket is improved. Can do.

  Further, in the cylinder head metal gasket according to the present invention, preferably, a rubber coating layer laid on the surface of the outer metal plate is a rubber coating layer laid on the surface of the metal plate around the cylinder hole. It is assumed that the hardness is lower. In this way, the sealing of the combustion gas at the peripheral part of the cylinder hole is relatively harder than the outer part, so the rubber coating layer that increases the surface pressure of the annular bead is sufficiently performed, while the sealing part from the peripheral part of the cylinder hole. Sealing of the cooling water in the cooling water jacket at the outer part outside is relatively harder than the peripheral part, so it can be sufficiently performed with a rubber coating layer that seals even at low surface pressures, and the overall sealing performance of the metal gasket is achieved. Can be improved as.

  Furthermore, in the metal gasket for a cylinder head according to the present invention, preferably, the coupling means is a shear extrusion coupling portion. If it does in this way, at least a cylinder hole peripheral part and an outer part can be easily couple | bonded in a short time by press work with a press die, NC punching press, etc.

  Further, in the cylinder head metal gasket of the present invention, preferably, the coupling means couples a plurality of the substrates. In this way, the substrates can be bonded to each other, and the mounting operation of the metal gasket between the cylinder block and the cylinder head can be made easier.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. FIG. 1 is a plan view showing the whole of the first embodiment of the cylinder head metal gasket according to the present invention, and FIG. 2 is a sectional view of the metal gasket of the first embodiment along the line AA in FIG. 3A is a plan view showing the upper substrate in FIG. 1 of the metal gasket of the first embodiment, and FIG. 3B is a bottom view of the metal gasket of the first embodiment in FIG. FIG. 3 (c) is a plan view showing the outer periphery of the lower substrate in FIG. 1 of the metal gasket of the first embodiment, and FIG. 4 (a). FIG. 4B is an enlarged plan view showing the joint portion of the metal gasket of the first embodiment, FIG. 4B is a cross-sectional view taken along the line CC of FIG. 4A, and FIG. It is sectional drawing which follows the DD line of 4 (a), and the same part as it shows to previous FIGS. It is shown by No.. That is, in the figure, reference numeral 1 denotes a metal gasket, and 2 denotes a substrate.

  As shown in FIG. 2, the cylinder head metal gasket 1 of the first embodiment includes two substrates 2 on which the beads corresponding to each other are overlapped with each other so as to protrude opposite each other. 2, the first substrate 2 positioned on the upper side is a rubber made of NBR having a layer thickness of 15 μm and a hardness of 81 Hs (Shore hardness) on both the outward surface (the surface facing the cylinder head) and the inward surface. It consists of a stainless steel plate (for example, SUS 301H with a thickness of 0.2 mm) provided with a coating layer 2g, and corresponds to each of a plurality of cylinder bores of a cylinder block of an internal combustion engine as shown in FIG. 1 and FIG. A plurality of cylinder holes 2a, an annular bead 2b having a chevron cross section (so-called full bead shape) formed around each cylinder hole 2a, and the cylinder of the internal combustion engine. A plurality of cooling water holes 2c formed in the outer peripheral portion of each annular bead 2b corresponding to the positions of the cooling water jacket of the lock and the cooling water hole of the cylinder head, and the plurality of annular beads 2b and the circumference thereof And an outer peripheral bead 2d having a one-sided cross-sectional shape (a so-called half bead shape) formed at a position surrounding the plurality of cooling water holes 2c as a whole.

  Further, as shown in FIG. 1, the second substrate 2 positioned on the lower side in FIG. 2 also includes a plurality of cylinder holes 2 a formed respectively corresponding to a plurality of cylinder bores of the cylinder block of the internal combustion engine. An annular bead 2b having a chevron cross-sectional shape (a so-called full bead shape) formed around the cylinder hole 2a, and each annular bead 2b corresponding to the position of the cooling water jacket of the cylinder block and the cooling water hole of the cylinder head of the internal combustion engine. A plurality of cooling water holes 2c formed in the outer peripheral portion of the outer peripheral surface, a plurality of annular beads 2b, and a single bevel-shaped cross-sectional shape formed in a position surrounding the plurality of cooling water holes 2c located around them. (A so-called half bead shape) outer peripheral bead 2d.

  In this configuration, in the cylinder head metal gasket 1 of the first embodiment, the first substrate 2 is formed of a single metal plate as shown in FIG. The substrate 2 has a cylinder hole peripheral portion 2e having an annular bead 2b as shown in FIG. 3B, a cooling water hole 2c, a part thereof, and an outer peripheral bead 2d outside the cylinder hole peripheral portion 2e. It is formed by a hole peripheral part 2e and an outer part 2f formed separately from the hole peripheral part 2e as shown in FIG. 3 (c). The cylinder hole peripheral part 2e has an outward surface (a surface facing the cylinder block) and an inner part. A stainless steel plate (for example, a plate) having a rubber coating layer 2g made of NBR having the same heat resistance as that of the first substrate 2 and having a hardness of 81 Hs (Shore hardness) on both sides of the first substrate 2. From SUS 301H with a thickness of 0.3 mm On the other hand, the outer portion 2f differs from the cylinder hole peripheral portion 2e on both the outward surface (surface facing the cylinder block) and the inward surface, for example, with a layer thickness of 25 μm and a hardness of 62 Hs (Shore hardness). Stainless steel plate with a single rubber coating layer 2h made of NBR with excellent LLC (long life coolant: a kind of cooling water mixed with antifreeze that can easily swell rubber) It is made of SUS 301H) having a hardness of 0.2 mm.

  As shown in FIG. 3 (b), a plurality of protrusions 2i protruding radially outward are formed in the cylinder hole peripheral portion 2e, and each of these protrusions 2i is formed in a cooling water jacket of a cylinder block of the internal combustion engine. At a corresponding position, as shown in FIG. 4, the outer substrate 2f and the first substrate 2 are integrally coupled by a shear extrusion coupling portion 5 as a coupling means, whereby the second substrate 2 is As shown in FIG. 2, it has a step structure S4 that makes the cylinder hole peripheral part 2e thicker than the outer part 2f.

  Here, as shown in FIGS. 4A to 4C, the shear-extrusion coupling portion 5 includes the first substrate 2, the projection 2i of the cylinder hole peripheral portion 2e of the second substrate 2, and the second substrate. Two outer parts 2f are stacked in order from the top, for example, a punch having a trapezoidal longitudinal cross-sectional shape and a rectangular cross-sectional shape, and a die having a rectangular hole that fits into the punch with a predetermined clearance with a larger short side. Can be formed by press working with a press die or a NC punching press (see, for example, Japanese Patent Application Laid-Open No. 6-281111). Then, by providing a bottom in the rectangular hole of the die and further pressing between the bottom and the punch (pressing the punch into the bottom), it may be crushed and expanded as shown in FIG. To make the bond Ri can be strengthened.

  In the cylinder head metal gasket 1 of the first embodiment, an annular bead 2b having a chevron cross section around a cylinder hole 2a formed corresponding to each cylinder bore of a cylinder block of an internal combustion engine has a step structure S4. The surface pressure of the cylinder block is increased so that the high-temperature and high-pressure combustion gas in the cylinder bore does not leak to the outside, while the outer peripheral bead 2d outside the periphery of the cylinder hole 2a Seal the cooling water in the cooling water jacket so that it does not leak to the outside, and under that sealing, the cooling water hole 2c flows the cooling water between the cooling water jacket of the cylinder block and the cooling water hole of the cylinder head. Enable.

  In the cylinder head metal gasket 1 of the first embodiment, the second substrate 2 has a cylinder hole peripheral portion 2e having an annular bead 2b and an outer peripheral bead 2d outside the cylinder hole peripheral portion 2e. The cylinder block peripheral portion 2e and the outer portion 2f formed separately, the cylinder hole peripheral portion 2e and the outer portion 2f of the cylinder block so as not to hinder the tightening of the cylinder head of the internal combustion engine. The rubber coating layer 2g and the outer portion 2f are integrally connected by a shear-extrusion joint portion 5 disposed at a position that can protrude from the cooling water jacket, and laid on the surface of the metal plate in the cylinder hole peripheral portion 2e. The annular bead is different from the rubber coating layer 2f laid on the surface of the metal plate, and the rubber coating layer 2g around the cylinder hole 2e is suitable for sealing of combustion gas. It is considered to be thin and hard to withstand the high surface pressure of 2b, and at the same time to be thick and soft to seal even at low surface pressure of the outer peripheral bead 2d so that the rubber coating layer 2h of the outer portion 2f is suitable for sealing of cooling water. ing.

  Therefore, according to the cylinder head metal gasket 1 of the first embodiment, while the combustion gas is sufficiently sealed at the cylinder hole peripheral portion 2e, the cooling water jacket is formed at the outer portion 2f outside the cylinder hole peripheral portion 2e. The cooling water inside can be sufficiently sealed, and the sealing performance of the metal gasket can be improved as a whole.

  FIG. 5 shows a 0.2 mm-thick SUS 301H stainless steel plate having a rubber coating layer on both sides, similar to the first substrate 2 of the first embodiment, and a hole similar to the cylinder hole 2a and an annular bead 2b surrounding it. It is a characteristic diagram showing the results of testing the seal limit pressure by tightening at a surface pressure of 26 MPa for specimens having the same bead part and different rubber coating layer thicknesses and rubber hardnesses. It can also be seen from the figure that the seal limit pressure is higher when the rubber hardness is lower (softer) if the layer thickness is the same, and the seal limit pressure is higher when the layer thickness is greater if the rubber hardness is the same.

  FIG. 6 is a characteristic diagram showing the results of testing the seal limit pressure with different bead surface pressures for specimens similar to the above, with rubber coating layers having a thickness of 20 μm and different rubber hardnesses. From this figure, it can be seen that if the rubber hardness is lowered, the seal limit pressure is increased, so that the required sealability can be ensured.

  Therefore, also from these test results, even when the surface pressure of the annular bead 2b is increased by providing the step structure S4 as described above, the surface pressure of the outer peripheral bead 2d is decreased. According to the metal gasket 1, when the rubber coating layer 2g of the cylinder hole peripheral part 2e is made thin and hard so as to withstand the high surface pressure of the annular bead 2b so as to be suitable for sealing of the combustion gas on the second substrate 2. At the same time, the rubber coating layer 2h of the outer part 2f is thick and soft so that it can be sealed even at a low surface pressure of the outer peripheral bead 2d so that it is suitable for cooling water sealing, so that the sealing performance can be improved as a whole. I understand that.

  In addition, according to the cylinder head metal gasket 1 of the first embodiment, the step structure S4 is configured with the metal plate of the cylinder hole peripheral portion 2e being thicker than the metal plate of the outer portion 2f. By appropriately selecting the difference in plate thickness, the surface pressure of the annular bead 2b is easily increased to the level necessary for the sealing of the combustion gas, and the surface pressure of the outer peripheral bead 2d is ensured to the level required for the sealing of the cooling water. be able to.

  Further, according to the cylinder head metal gasket 1 of the first embodiment, the rubber coating layer 2g laid on the surface of the metal plate around the cylinder hole 2e is excellent in heat resistance, and the outer portion 2f Since the rubber coating layer 2h laid on the surface of the metal plate has excellent LLC resistance, the rubber coating layer 2g with excellent heat resistance is used to seal the combustion gas around the cylinder hole 2e. Cooling water in the cooling water jacket at the outer part 2f outside the cylinder hole peripheral part 2e can be sufficiently sealed with the rubber coating layer 2h with excellent cooling water resistance, and the sealing performance of the metal gasket as a whole Can be improved.

  Furthermore, according to the cylinder head metal gasket 1 of the first embodiment, since the coupling means is the shear extrusion coupling portion 5, the cylinder of the second substrate 2 can be formed by pressing with a press die or NC punching press. The hole peripheral portion 2e, the outer portion 2f, and the first substrate 2 can be easily combined in a short time, and by this connection, the metal gasket can be more easily mounted between the cylinder block and the cylinder head. It can be easy.

  FIG. 7 is a cross-sectional view of the second embodiment of the cylinder head metal gasket of the present invention at the same position as in FIG. 2, and the cylinder head metal gasket 1 of the second embodiment also corresponds to each other. There are provided two substrates 2 which are stacked on each other in a direction in which the beads protrude to face each other. In the two substrates 2 here, the metal plate constituting the cylinder hole peripheral portion 2e is the same as the metal plate constituting the outer portion 2f, and the hardness is the metal plate constituting the outer portion 2f. The second substrate 2 is different from the second substrate 2 of the first embodiment in a higher (hard) point, and is configured in the same manner as the second substrate 2 of the first embodiment in other points.

  Further, in the cylinder head metal gasket 1 of the second embodiment, the cylinder holes of the respective substrates 2 are formed by a plurality of shear extrusion coupling portions 5 arranged at the same positions as in the cylinder head metal gasket 1 of the first embodiment. The peripheral portion 2e and the outer portion 2f are integrally coupled, and the two substrates 2 are also integrally coupled.

  According to the cylinder head metal gasket 1 of the second embodiment, in addition to the effects similar to those of the first embodiment, both the two substrates 2 have the metal in the cylinder hole peripheral portion 2e. Since the plate is harder than the metal plate of the outer portion 2f, the surface pressure of the annular bead 2b can be greatly increased without a step structure. Also, the rubber coating layer 2g laid on the surface of the metal plate in the cylinder hole peripheral part 2e is heat resistant by changing the rubber coating layer in the cylinder hole peripheral part 2e and the outer part 2f in both of the two substrates 2. Since the rubber coating layer 2h laid on the surface of the metal plate of the outer part 2f has excellent LLC resistance, the sealing of the combustion gas at the cylinder hole peripheral part 2e is heat resistant. The rubber coating layer 2h with excellent cooling water resistance is sufficient to seal the cooling water in the cooling water jacket at the outer part 2f outside the cylinder hole peripheral part 2e. As a result, the sealing performance of the metal gasket can be further improved as a whole.

  FIG. 8 is a sectional view showing a third embodiment of the cylinder head metal gasket according to the present invention at the same position as in FIG. 2, and the cylinder head metal gasket 1 of the third embodiment also corresponds to each other. There are provided two substrates 2 which are stacked on each other in a direction in which the beads protrude to face each other. Here, one (upper side in the figure) substrate 2 is configured in the same manner as the first substrate 2 of the first embodiment, and the other (lower side in the figure) substrate 2 forms a cylinder hole peripheral portion 2e. The metal plate has the same thickness as the metal plate constituting the outer portion 2f, the hardness is higher (hard) than the metal plate constituting the outer portion 2f, and the metal plate constituting the cylinder hole peripheral portion 2e This is different from the second substrate 2 of the first embodiment in that the metal plate constituting the outer portion 2f is overlapped with the metal plate constituting the cylinder hole peripheral portion 2e facing outside. The configuration is the same as that of the second substrate 2 of the first embodiment.

  Further, in the cylinder head metal gasket 1 according to the third embodiment, the plurality of shear extrusion coupling portions 5 arranged at the same positions as those in the cylinder head metal gasket 1 according to the first embodiment are used. The cylinder hole peripheral portion 2e and the outer portion 2f are integrally coupled, and the two substrates 2 are also integrally coupled.

  According to the cylinder head metal gasket 1 of the third embodiment, the same effect as that of the first embodiment can be obtained, and in addition, the metal plate in the cylinder hole peripheral portion 2e of the other substrate 2 can be provided. Since the hardness is higher than that of the metal plate of the outer portion 2f, the surface pressure of the annular bead 2b can be increased without a step structure.

  FIG. 9 is a sectional view showing a fourth embodiment of the cylinder head metal gasket according to the present invention at the same position as in FIG. 2, and the cylinder head metal gasket 1 of the fourth embodiment also corresponds to each other. There are provided two substrates 2 which are stacked on each other in a direction in which the beads protrude to face each other. In the two substrates 2 here, the metal plate constituting the cylinder hole peripheral portion 2e is the same as the metal plate constituting the outer portion 2f, and the hardness is the metal plate constituting the outer portion 2f. The higher (hard) point and the metal plate constituting the cylinder hole peripheral part 2e and the metal plate constituting the outer part 2f are overlapped with the metal plate constituting the cylinder hole peripheral part 2e facing outside The second substrate 2 is different from the second substrate 2 of the first embodiment, and is otherwise configured in the same manner as the second substrate 2 of the first embodiment.

  Further, in the cylinder head metal gasket 1 of the fourth embodiment, the cylinder holes of the respective substrates 2 are formed by a plurality of shear extrusion coupling portions 5 arranged at the same positions as in the cylinder head metal gasket 1 of the first embodiment. The peripheral portion 2e and the outer portion 2f are integrally coupled, and the two substrates 2 are also integrally coupled.

  According to the cylinder head metal gasket 1 of the fourth embodiment, the same effects as those of the second embodiment can be provided.

  Although the present invention has been described based on the illustrated examples, the present invention is not limited to the above-described examples. For example, in the first to fourth embodiments, the metal plate constituting the cylinder hole peripheral portion 2e is removed. Thickness and hardness may be higher than the metal plate constituting the side part 2f, and the rubber coating layer 2g of the cylinder hole peripheral part 2e and the rubber coating layer 2h of the outer part 2f may be hardened to each other. The rubber coating layer 2h may be thicker only in the same thickness, or the rubber coating layer 2h may be softer only in hardness with the same layer thickness.

  And in this invention, it replaces with the shear extrusion coupling | bond part 5 in the said 1st Example thru | or 4th Example, You may use an eyelet, a grommet, and a rivet, and the metal plate which comprises the cylinder hole peripheral part 2e And the metal plate constituting the outer portion 2f may be joined by butt laser welding or the like.

  Furthermore, the cylinder head metal gasket of the present invention may be composed of only one substrate obtained by combining the metal plate constituting the cylinder hole peripheral portion 2e and the metal plate constituting the outer portion 2f, Moreover, you may combine with a subplate suitably.

  Thus, according to the metal gasket for a cylinder head of the present invention, it is inserted between the cylinder block of the internal combustion engine and the cylinder head, and the periphery of the cylinder hole is sufficiently sealed while sufficiently sealing the combustion gas around the cylinder hole. Since the cooling water in the cooling water jacket is sufficiently sealed at the outer part outside the part, the sealing performance of the metal gasket can be improved as a whole.

It is a top view which shows the whole 1st Example of the metal gasket for cylinder heads of this invention. It is sectional drawing which follows the AA line of FIG. 1 of the metal gasket of the said 1st Example. (A) is a plan view showing the upper substrate in FIG. 1 of the metal gasket of the first embodiment, and (b) is a cylinder hole periphery of the lower substrate in FIG. 1 of the metal gasket of the first embodiment. FIG. 1C is a plan view showing an outer portion of the lower substrate in FIG. 1 of the metal gasket of the first embodiment. (A) is an enlarged plan view showing the joint portion of the metal gasket of the first embodiment, (b) is a cross-sectional view taken along the line C-C of (a), and (c) is of (a). It is sectional drawing which follows the DD line. It is a characteristic diagram which shows the result of having tested the seal limit pressure about the several types of test body from which the layer thickness and rubber hardness of a rubber coating layer mutually differ. It is a characteristic diagram which shows the result of having tested the seal | sticker limit pressure by making the bead part surface pressure different about the several types of test body from which rubber hardness mutually differs. It is sectional drawing in the same position as FIG. 2 of 2nd Example of the metal gasket for cylinder heads of this invention. It is sectional drawing in the same position as FIG. 2 of 3rd Example of the metal gasket for cylinder heads of this invention. It is sectional drawing in the same position as FIG. 2 of 4th Example of the metal gasket for cylinder heads of this invention. It is sectional drawing which shows an example of the level | step difference structure of the conventional metal gasket for cylinder heads. It is sectional drawing which shows another example of the level | step difference structure of the conventional metal gasket for cylinder heads. It is sectional drawing which shows another example of the level | step difference structure of the conventional metal gasket for cylinder heads.

Explanation of symbols

1 Metal gasket for cylinder head 2 Substrate
2a Cylinder hole
2b annular bead
2c Cooling water hole
2d outer bead
2e Cylinder hole periphery
2f Outer part
2g Rubber coating layer around cylinder hole
2h Outer rubber coating layer
2i Protrusion 3 Sub-plate 4 Shim plate 5 Shear extrusion joint
LW laser welded part S1-S4 Step structure

Claims (8)

A cylinder hole (2a) made of a metal plate and corresponding to each cylinder bore of a cylinder block of an internal combustion engine, an annular bead (2b) having a chevron cross-sectional shape formed around each cylinder hole, and A cooling water hole (2c) formed in the outer peripheral portion of each annular bead corresponding to the cooling water jacket of the cylinder block and the cooling water hole of the cylinder head, and generally surrounds the annular bead and the cooling water hole. Metal cylinder gasket for a cylinder head having an outer peripheral bead (2d) having a one-sided cross-sectional shape formed at a position and at least one substrate (2) laid with a rubber coating layer on at least an outward surface In
At least one of the substrates has a cylinder hole peripheral part (2e) having the annular bead and an outer peripheral bead (2d) outside the cylinder hole peripheral part and formed separately from the cylinder hole peripheral part. And (2f)
The rubber coating layer (2g) laid on the surface of the metal plate around the cylinder hole (2e) is different from the rubber coating layer (2h) laid on the surface of the metal plate on the outer side (2f). And
The cylinder head metal gasket, wherein the cylinder hole peripheral part (2e) and the outer part (2f) are joined by a joining means (5) at a position corresponding to the cooling water jacket.   The metal gasket for a cylinder head according to claim 1, wherein the metal plate in the cylinder hole peripheral part (2e) is thicker than the metal plate in the outer part (2f).   The metal gasket for a cylinder head according to claim 1 or 2, wherein the metal plate in the cylinder hole peripheral part (2e) has higher hardness than the metal plate in the outer part (2f). The rubber coating layer (2g) laid on the surface of the metal plate around the cylinder hole (2e) is excellent in heat resistance,
The cylinder according to any one of claims 1 to 3, wherein the rubber coating layer (2h) laid on the surface of the metal plate of the outer part (2f) has excellent cooling water resistance. Metal gasket for the head.   The rubber coating layer (2h) laid on the surface of the metal plate of the outer part (2f) is thicker than the rubber coating layer (2g) laid on the surface of the metal plate of the cylinder hole peripheral part (2e). The metal gasket for a cylinder head according to any one of claims 1 to 4, wherein the metal gasket is thick.   The rubber coating layer (2h) laid on the surface of the metal plate of the outer part (2f) is harder than the rubber coating layer (2g) laid on the surface of the metal plate of the cylinder hole peripheral part (2e). The metal gasket for a cylinder head according to any one of claims 1 to 5, wherein the metal gasket is low.   7. The metal gasket for a cylinder head according to claim 1, wherein the coupling means is a shear extrusion coupling part (5).   The metal gasket for a cylinder head according to any one of claims 1 to 7, wherein the joining means (5) joins a plurality of the substrates (2).

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