JP2005214329A - Metal gasket for cylinder head - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To keep high sealing ability for a long period by preventing permanent set in fatigue of an annular bead. <P>SOLUTION: This metal gasket for a cylinder head includes: at least one base plate 2 formed of a metal plate, which has a cylinder hole 2a formed corresponding to each cylinder bore of a cylinder block, double annular beads 2b, 2c having a one-sided slant section, which are formed in the reverse directions in the periphery of each cylinder bore at a space in the radial direction, a cooling water hole 2d formed on the outer peripheral part of each annular bead corresponding to the cooling water holes of a cooling water jacket and a cylinder head of the cylinder block, and an outer peripheral bead 2e having a one-sided slant section, which is formed in a position to surround the annular bead and the cooling water hole on the whole; and a step adjusting plate 3 formed of a metal plate, which has an annular superposition part positioned in the region of a recessed part 2f formed by the double annular beads 2b, 2c of the base plate 2 opposite to the recessed part, and is superposed on the base plate to be extended from the superposition part to the outer peripheral edge part of the base plate 2. <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.

  A metal gasket is usually inserted at the joint between the cylinder block and the cylinder head constituting the internal combustion engine, and this metal gasket has a bead formed to seal the deck surface of the cylinder block and the cylinder head. This bead is compressed and elastically deformed by a fastening force of a fastening bolt that fastens the cylinder head to the cylinder block, and forms a seal line on the deck surface to provide a sealing action.

  As this type of metal gasket, there is conventionally known, for example, the one shown in FIG. The cylinder head metal gasket 1 includes a cylinder hole 2a formed corresponding to each cylinder bore 7a of a cylinder block 7 of an internal combustion engine, and an annular bead 2g having a chevron-shaped cross section formed around each cylinder hole 2a. A cooling water hole 2d formed on the outer periphery of each annular bead 2g corresponding to the cooling water jacket 7b of the cylinder block 7 and the cooling water hole 8a of the cylinder head 8, and the annular bead 2g and the cooling It has two substrates 2 each made of a metal plate, each having an outer peripheral bead 2e having a one-sided cross-sectional shape formed at a position surrounding the water hole 2d as a whole. Each of the annular beads 2b protrudes with the top portions facing each other.

  The cylinder head metal gasket 1 includes a step adjustment plate 3 interposed between the two substrates 2, and the step adjustment plate 3 is cooled with each cylinder hole 2 a of the two substrates 2. A cylinder hole 3a and a cooling water hole 3c respectively corresponding to the water hole 2d and a grommet portion 3e sandwiched between the annular beads 2g of the two substrates 2 and having an inner peripheral edge forming the cylinder hole 3a Yes. In the figure, reference numeral 9 denotes the above-described tightening bolt. The tightening bolt 9 prevents the leakage of cooling water into the bolt hole, and the two substrates 2 and the level difference adjusting plate 3 are positioned outside the outer peripheral bead 2e of the substrate 2. It penetrates.

According to this conventional cylinder head metal gasket 1, the grommets 3e that are folded and overlapped with the step adjusting plate 3 have a shim step structure, and this shim step structure allows the cylinder holes 2a and 3a and the gasket outer peripheral side to be connected to each other. A step of Tt = H is generated between the two, and the axial force of the tightening bolt acts as an annular bead pressing load on the annular bead 2g intensively by this generated step H, so that the annular bead 2g is highly sealed. Cause it to occur.
JP-A-8-121597

  By the way, as a result of the inventor's research on the conventional cylinder head metal gasket 1, in this cylinder head metal gasket 1, the shim step structure constituted by the grommet portion 3e is an annular bead 2g having a cross-sectional shape. Since it is in contact with the top, the annular bead 2g is compressed and deformed to a nearly flat shape between the cylinder block 7 and the cylinder head 8, and the internal pressure and engine due to the combustion gas in the cylinder bore 7a in the flat compressed state. The gap between the deck surfaces around the cylinder bore 7a expands and contracts due to heat, so an alternating load is applied to the annular bead 2g, causing a sag in the annular bead 2g, and the spring characteristics of the annular bead 2g are reduced. It becomes difficult to continue to apply a predetermined seal surface pressure to the deck surface, which may lead to a decrease in sealing performance. We have found that there is anxiety about long-term maintenance of high sealing performance against combustion gas in a.

  An object of the present invention is to advantageously solve the above-described problems, and a cylinder head metal gasket according to the present invention includes a cylinder hole formed corresponding to each cylinder bore of a cylinder block of an internal combustion engine, A double annular bead having a single beveled cross-sectional shape formed around the cylinder holes in opposite directions and spaced apart from each other in the radial direction; a cooling water jacket of the cylinder block; and a cooling water hole of the cylinder head A cooling water hole formed in the outer peripheral portion of each annular bead and an outer peripheral bead having a one-sided cross-sectional shape formed at a position entirely surrounding the annular bead and the cooling water hole. And having at least one substrate made of a metal plate and a pair of the recess located within the recess formed by the double annular bead of the substrate. Has an annular polymerization unit which extends to the position of the outer peripheral edge of the substrate from at least the overlapping portion is superposed on the substrate is made comprises the step adjustment plate made of a metal plate, a.

  In such a cylinder head metal gasket according to the present invention, the overlapping portion of the step adjusting plate constitutes a shim step structure, and this shim step structure causes a step between the cylinder hole side of the metal gasket and the gasket outer peripheral side. As a result of this step, the axial force of the tightening bolt acts intensively on the double annular beads of the substrate as an annular bead pressing load, giving these annular beads a high sealing performance against the combustion gas in the cylinder bore. Cause it to occur. Further, although the allocated amount is reduced by the shim step structure, the axial force of the tightening bolt acts on the outer peripheral bead as a pressing load due to the deformation of the cylinder head, thereby causing the outer peripheral bead to have a sealing property against the cooling water.

  Moreover, in the cylinder head metal gasket of the present invention, the overlapping portion of the step adjusting plate is located within the range of the recess formed by the double annular bead of the substrate and faces the recess. The double annular bead is compressed and deformed almost flat because the double annular bead of the substrate and the annular overlapping part of the step adjustment plate located between them form a triple seal line surrounding the cylinder bore. Even if it is not performed, the same high sealing performance as that in the case where the top portion of the conventional annular bead having the cross-sectional shape and the grommet portion are brought into contact with each other can be obtained. Furthermore, even if the axial force of the tightening bolt is concentrated on the annular bead, the annular bead is prevented from being crushed by the level difference of the overlapping portion located inside the concave portion, and the annular bead is compressed and deformed to a nearly flat shape. Therefore, the gap between the deck surfaces around the cylinder bore expands and contracts due to the internal pressure of the combustion gas in the cylinder bore and the engine heat, and the annular bead sags even if an alternating load is applied to the annular bead. There is no.

  Therefore, according to the metal gasket for a cylinder head of the present invention, it is possible to achieve a high sealing performance against the combustion gas in the cylinder bore and to maintain the spring characteristics of the annular bead over a long period of time on the deck surface. The tightening bolt can maintain a predetermined sealing surface pressure and maintain the spring characteristics of the annular bead so that the balance between the axial force of the tightening bolt and the pressing load of the annular bead at the time of initial fastening does not collapse thereafter. Therefore, the high sealing performance can be reliably maintained for a long time.

  In the cylinder head metal gasket according to the present invention, the step adjusting plate is a sub-plate that extends from the inside of the recess formed by the double annular bead of the substrate to the position of the outer peripheral edge of the substrate. And extending radially outward from a position radially inward of the double annular bead of the substrate to within the range of the recess formed by the double annular bead. A shim plate that is superposed and fixed on the plate to form the overlapping portion, and the outer peripheral edge of the substrate from a position radially inward of the double annular bead of the substrate At least one of the superposition part which is overlapped and fixed to the sub-plate so as to be located within the range of the concave portion formed by the double annular bead of the substrate and the double annular bead of the substrate. Sheets A sub-plate that extends from the range of the recess formed by the double annular bead of the substrate to the position of the outer peripheral edge of the substrate, and the double plate of the substrate. There may be provided at least one shim plate that is overlapped and fixed to the sub-plate so as to be positioned within the range of the concave portion formed by the annular bead and constitutes the overlapping portion.

  In the cylinder head metal gasket according to the present invention, the step adjustment plate includes a main portion extending from the range of the recess formed by the double annular bead of the substrate to the position of the outer peripheral edge of the substrate. A grommet portion that is folded back from the main portion within the range of the concave portion formed by the double annular bead of the substrate and is superimposed on the main portion within the range of the concave portion to constitute the overlapping portion. A sub-plate extending from the range of the recess formed by the double annular bead of the substrate to the position of the outer peripheral edge of the substrate; and the double annular bead of the substrate And a grommet plate that is folded back within the range of the concave portion formed and overlapped with the sub-plate within the range of the concave portion to constitute the overlapped portion.

  In the cylinder head metal gasket according to the present invention, the metal gasket includes the substrate in two directions in which the concave portions formed by the double annular beads face each other. It may be located between the substrates.

  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. FIG. 2 is a sectional view of the metal gasket of the first embodiment taken along the line II-II in FIG. Sectional views, and FIGS. 3 (a) and 3 (b) show the metal gasket of the first embodiment inserted between a cylinder block and a cylinder head of an internal combustion engine and tightened with a tightening bolt. It is sectional drawing in the position similar to FIG. 2, and the principal part expanded sectional view, In the figure, the part similar to the said prior art example is shown with the same code | symbol. That is, in the figure, reference numeral 1 denotes a metal gasket, 2 denotes a substrate, and 3 denotes a step adjustment plate.

  As shown in FIG. 2, the cylinder head metal gasket 1 of the first embodiment includes two substrates 2 each made of a metal plate. These substrates 2 are also shown in FIG. Cylinder holes 2a formed corresponding to the respective cylinder bores 7a of the cylinder block 7 of the internal combustion engine, and formed around the cylinder holes 2a in opposite directions and at intervals in the radial direction of the cylinder holes 2a. A double annular bead 2b, 2c composed of a double bead having a single beveled cross section (this is called a “double half bead”), a cooling water jacket 7b of the cylinder block 7 and a cylinder head 8 A cooling water hole 2d formed in the outer periphery of the double annular beads 2b, 2c corresponding to the cooling water hole 8a, and a position surrounding the double annular beads 2b, 2c and the cooling water hole 2d as a whole The monoclinic formed on An outer peripheral bead 2e having a planar cross-sectional shape (so-called half bead shape), and further, a bolt hole 2h through which the tightening bolt 9 is inserted and a lubricating oil hole 2i outside the outer peripheral bead 2e. Yes.

  Further, the cylinder head metal gasket 1 according to the first embodiment has, as shown in FIG. 2, a step adjustment plate 3 formed of a metal plate having a thickness smaller than that of the substrate 2 between the two substrates 2, for example. The level difference adjusting plate 3 is provided from the position of each cylinder hole 2a of the two substrates 2 (the position corresponding to the cylinder hole 2a) to the position of the outer peripheral edge of the substrate 2 (outside). The outer peripheral contour shape is substantially the same as those of the substrates 2 and the cylinder holes 3a corresponding to the respective cylinder holes 2a of the substrates 2 are provided so as to extend to a position corresponding to the peripheral edge). Yes. The step adjusting plate 3 has a plurality of holes 3c corresponding to the cooling water holes 2d, the lubricating oil holes 2g, and the bolt holes 2f of the respective substrates 2 in addition to the cylinder holes 3a.

  As shown in FIGS. 1 and 2, the level difference adjusting plate 3 is also located in the range of the recess 2f formed by the double annular beads 2b and 2c of the substrate 2 and is opposed to the recess. In order to form this overlapping portion 3b, the level difference adjusting plate 3 is provided from the range of the recess 2f formed by the double annular beads 2b and 2c of the substrate 2 to the position of the outer peripheral edge of the substrate 2. From the extended sub-plate 4 and the position of each cylinder hole 2a that is radially inward of the double annular beads 2b, 2c of the substrate 2, the recess 2f formed by the double annular beads 2b, 2c is formed. It has an annular shim plate 5 that extends radially outward to within the range and is superimposed on the sub-plate 4 within the range of the recess 2f and fixed by, for example, spot welding or laser welding.

  In the cylinder head metal gasket 1 of the first embodiment, for example, the substrate 1 is formed of a stainless steel plate (spring material) having a plate thickness of 0.15 to 0.35 mm, and a double annular bead 2b, 2c has a bead height of 0.1 to 0.4 mm, a bead width of 2.5 to 4.5 mm, a flat top portion between the annular beads 2b and 2c, a width of A portion of 1 to 3 mm, The level difference adjusting plate 3 is preferably formed of a stainless steel plate (spring material) having a thickness of 0.05 to 0.15 mm, and the width of the B portion which is the overlapping portion 3b is preferably 1 to 3 mm. Here, the width of the B portion is slightly smaller than the width of the A portion in the illustrated example of FIG. 2, but may be equal to the width of the A portion.

  In the cylinder head metal gasket 1 according to the first embodiment, the overlapping portion 3b of the step adjusting plate 3 constitutes a shim step structure. As shown in FIG. When the metal gasket 1 is inserted between the cylinder block 7, the cylinder head 8 and the deck surface and tightened with the tightening bolt 9, the metal gasket 1 is tightened at the position of the overlapping portion 3b near the cylinder holes 2a and 3a. A step H is generated between the gasket thickness T and the gasket thickness t when tightening on the outer peripheral side of the gasket, and the axial force of the tightening bolt 9 is the double annular bead 2b of the substrate 2 corresponding to the generated step H. The ring beads 2b and 2c act intensively as an annular bead pressing load on 2c, and a high sealing performance against the combustion gas in the cylinder bore 7a is produced on these annular beads 2b and 2c. In addition, although the shim step structure is less than when the shim step structure is not provided, the axial force of the tightening bolt 9 acts on the outer peripheral bead 2e as a pressing load due to the deformation of the cylinder head 8, and the outer peripheral bead 2e is placed in the coolant jacket 7b. Produces sealing performance against cooling water.

  Moreover, in the cylinder head metal gasket 1 of the first embodiment, the overlapping portion 3b of the step adjusting plate 3 is located within the range of the recess 2f formed by the double annular beads 2b and 2c of the substrate 2. Because it is opposed to the concave portion 2f, a triple seal line surrounding the cylinder bore 7a is formed by the double annular beads 2b, 2c and the annular overlapping portion 3b positioned therebetween, Even if the double annular beads 2b and 2c are not compressed to near flatness and have a compression rate of 50 to 80% of the bead height, the top of the conventional annular bead 2g and the grommet 3e The same high sealing performance as that in the case of contacting is obtained. Further, even if the axial force of the tightening bolt 9 is concentrated on the annular beads 2b and 2c, the annular beads 2b and 2c are prevented from being crushed by the step H of the overlapping portion 3b located inside (within the range) of the recess 2f. Since the annular beads 2b and 2c are not compressed and deformed almost completely flat, the clearance between the deck surfaces around the cylinder bore 7a is expanded and contracted due to the internal pressure of the combustion gas in the cylinder bore 7a and the influence of the engine heat. Thus, even if an alternating load is applied to the annular beads 2b and 2c, the annular beads 2b and 2c do not sag.

  In the cylinder head metal gasket 1 of the first embodiment, the sub-plate 4 and the shim plate 5 of the step adjusting plate 3 are deformed in accordance with the substrate 2 as shown in FIG. Since the plate thickness is thinner than the substrate 2 so as to be located at the center of the substrate 2, the distance a from the center position in the thickness direction of the metal gasket 1 to the surfaces of the sub-plate 4 and the shim plate 5 Is symmetrical in the thickness direction with respect to the center position, and the bead compression amount of the two substrates 2 is uniform, so that it is possible to prevent the sag from being biased to the annular beads 2b and 2c of only one substrate 2. And can exhibit excellent durability.

  4 to 8 are sectional views of the metal gasket for a cylinder head according to the present invention in the second embodiment to the sixth embodiment, respectively, at the same positions as in FIG. 2, and these second to sixth embodiments. Since each cylinder head metal gasket 1 of the embodiment includes the same substrate 2 as in the first embodiment, the following description will mainly focus on the differences from the first embodiment.

  The cylinder head metal gasket 1 of the second embodiment shown in FIG. 4 includes the two substrates 2 and a step adjusting plate 3 interposed between them. 3 has substantially the same outer peripheral contour shape as that of the substrate 2 as in the first embodiment, and has cylinder holes 3a corresponding to the cylinder holes 2a of the substrates 2, respectively. The step adjusting plate 3 also has a plurality of holes 3c corresponding to the cooling water holes 2d, the lubricating oil holes 2g, and the bolt holes 2f of the respective substrates 2, in addition to the cylinder holes 3a.

  As shown in FIG. 4, the level difference adjusting plate 3 also has an annular overlapping portion 3b that is located in the range of the recess 2f formed by the double annular beads 2b and 2c of the substrate 2 and faces the recess. In order to form this overlapping portion 3b, the level difference adjusting plate 3 in this embodiment is formed on the substrate 2 from the position of the cylinder hole 2a which is a position radially inward of the double annular beads 2b and 2c of the substrate 2. The sub-plate 4 extending to the position of the outer peripheral edge and the spot 2 are superimposed on both surfaces of the sub-plate 4 so as to be positioned within the range of the recess 2f formed by the double annular beads 2b and 2c of the substrate 2, for example. And two annular shim plates 5 fixed by welding, laser welding, or the like.

  The cylinder head metal gasket 1 of the third embodiment shown in FIG. 5 includes the two substrates 2 and a step adjusting plate 3 interposed between them. 3, the sub-plate 4 does not extend radially inward to the position of each cylinder hole 2a of the substrate 2 with respect to the step adjusting plate 3 in the second embodiment shown in FIG. 4, and the sub-plate 4 in the first embodiment. In the same manner as in the second embodiment, the difference is only in that it ends within the range of the double annular beads 2b and 2c of the substrate 2, and the other points are the same as the step adjustment plate 3 in the second embodiment.

  A cylinder head metal gasket 1 according to the fourth embodiment shown in FIG. 6 includes a single substrate 2 and a step adjustment plate 3 along the recess 2f side of the substrate 2. The level difference adjusting plate 3 is different from the level difference adjusting plate 3 in the second embodiment shown in FIG. 4 only in that the shim plate 5 is fixed to only one side of the sub plate 4 and the other points. Then, it is comprised similarly to the level | step difference adjustment plate 3 in 2nd Example.

  The cylinder head metal gasket 1 of the fifth embodiment shown in FIG. 7 includes a single substrate 2 and a step adjustment plate 3 along the concave portion 2f side of the substrate 2. The level difference adjusting plate 3 is different from the level difference adjusting plate 3 in the third embodiment shown in FIG. 5 only in that the shim plate 5 is fixed to only one side of the sub plate 4 and other points. Then, it is comprised similarly to the level | step difference adjustment plate 3 in 3rd Example.

  The cylinder head metal gasket 1 of the sixth embodiment shown in FIG. 8 includes a single substrate 2 and a step adjusting plate 3 along the recess 2f side of the substrate 2. The level difference adjusting plate 3 is configured similarly to the level difference adjusting plate 3 in the third embodiment shown in FIG.

  The cylinder head metal gaskets 1 of the second to sixth embodiments can provide the same effects as those of the first embodiment, and in addition, the second, third and sixth embodiments. According to the example, since the two shim plates 5 are provided, the step H can be further increased, and according to the third, fifth and sixth embodiments, the step adjusting plate 3 is provided on each cylinder of the substrate 2. Since it does not extend radially inward to the position of the hole 2a, the amount of compressive deformation of the inner annular bead 2b can be further reduced, and the inner annular bead 2b can be more reliably prevented from sagging.

  FIG. 9 shows a seventh embodiment of the cylinder head metal gasket according to the present invention, and is a cross-sectional view at the same position as in FIG. 2. FIG. 10 (a) shows the cylinder head metal gasket of the seventh embodiment. FIG. 10B and FIG. 10C are cross-sectional views at the same positions as in FIG. 9, which are shown in a state where they are inserted between the cylinder block and the cylinder head of the internal combustion engine but are not tightened with the tightening bolts. FIG. 9 is a cross-sectional view at the same position as in FIG. 9 showing a state in which the cylinder head metal gasket of the seventh embodiment is inserted between a cylinder block and a cylinder head of an internal combustion engine and tightened with a tightening bolt. FIG. 7 is an enlarged cross-sectional view of the cylinder head metal gasket 1 of the seventh embodiment, in which two substrates 2 identical to the substrate 2 of the first embodiment are recessed. 2f each other is equipped in a direction opposite to each other.

  The cylinder head metal gasket 1 of the seventh embodiment also includes a step adjustment plate 3 interposed between the two substrates 2. The step adjustment plate 3 here is the same as that of the first embodiment. Similar to the sub-plate 4, it has substantially the same outer peripheral shape as the substrate 2, but does not extend radially inward to the position of each cylinder hole 2 a of the substrate 2, and the double annular bead of the substrate 2 2b, 2c has a main portion 3d ending within the range of the recess 2f, and the main portion 3d has a plurality of cooling water holes 2d, lubricating oil holes 2g and bolt holes 2f respectively corresponding to the substrates 2. Hole 3c.

  Further, the step adjusting plate 3 here includes a grommet portion 3e that is folded back from the main portion 3d within the range of the concave portion 2f of the substrate 2 and overlaps and extends over the main portion 3d within the range of the concave portion 2f. The grommet portion 3e and the portion of the main portion 3d that overlaps the grommet portion 3e constitute a superposed portion 3b in this embodiment. Here, the grommet portion 3e is formed, for example, in the material plate of the step adjustment plate 3 by concentrating each cylinder hole 2a of the substrate 2 with a lower hole having an inner diameter smaller than the diameter of the folding position, and with a press mold, the radius from the folding position. It can be formed by once raising the inner portion in the direction and then folding it back and expanding it by press molding.

  In the cylinder head metal gasket 1 of the seventh embodiment, for example, the substrate 1 is formed of a stainless steel plate (spring material) having a thickness of 0.15 to 0.35 mm, and a double annular bead 2b, 2c has a bead height of 0.1 to 0.4 mm, a bead width of 2.5 to 4.5 mm, a flat top portion between the annular beads 2b and 2c, a width of A portion of 1 to 3 mm, The level difference adjusting plate 3 is preferably formed of a stainless steel plate (spring material) having a thickness of 0.05 to 0.15 mm, and the width of the B portion which is the overlapping portion 3b is preferably 1 to 3 mm. Here, the width of the B portion is slightly smaller than the width of the A portion in the illustrated example of FIG. 9, but may be equal to the width of the A portion.

  According to the cylinder head metal gasket 1 of the seventh embodiment, the same effects as those of the first embodiment can be obtained. In addition, according to the seventh embodiment, the step adjusting plate 3 is a substrate. Since it does not extend inward in the radial direction to the position of each cylinder hole 2a, the amount of compressive deformation of the inner annular bead 2b can be made smaller, and the inner annular bead 2b can be more reliably prevented from sag. Can do.

  FIG. 11 shows the cylinder head metal gasket 1 of the seventh embodiment and the conventional cylinder head metal gasket 1 shown in FIG. 16 in which the pressing load on the annular bead surrounding the cylinder bore is set to a plurality of sizes. FIG. 12 is a characteristic diagram showing the relationship between the pressing load and the restoring bead height when measuring the restoring bead height when the pressing load is removed with respect to the plurality of pressing loads, and FIG. For the cylinder head metal gasket 1 of the seventh embodiment and the conventional cylinder head metal gasket 1 shown in FIG. 16, the fastening load (axial force) of the tightening bolt 9 is set to a plurality of sizes, and the plurality of sizes are set. The fastening load (axial force) of the fastening bolt 9 when the pressing load applied to the annular bead surrounding the cylinder bore with respect to the fastening load is measured. FIG. 6 is a characteristic diagram showing the relationship with the pressing load of the shaped beads, in which the reference numeral G1 denotes the conventional cylinder head metal gasket 1 and G2 denotes the cylinder head metal gasket 1 of the seventh embodiment. The step H (H = T−t) of the step adjustment plate 3 of the metal gaskets G1 and G2 of the conventional and seventh embodiments is 100 μm.

  As is clear from FIG. 11, the conventional metal gasket G1 has a continuously reduced height of the restored bead as the annular bead pressing load increases. However, the metal gasket G2 of the seventh embodiment is initially an annular bead. Although the restored bead height decreases as the pressing load increases, the restored bead height does not decrease when the annular bead pressing load is F2 or more. In the metal gasket G2 of the seventh embodiment, the grommet portion 3e constituting the overlapping portion 3b is located within the recess 2f of the double annular beads 2b, 2c, and the annular beads 2b, 2c are completely It is considered that this is because the flattening is prevented. From this result, it is clear that the metal bead G2 of the seventh embodiment has a reduced ring bead sag than the conventional metal gasket G1. In addition, the horizontal broken line in FIG. 11 is a bead height after an engine operation test incorporated in an actual engine (in the figure, reference numeral Hb2 is the conventional cylinder head metal gasket 1 and Hb1 is the cylinder head of the seventh embodiment). The metal gasket 1) is shown, and also in this broken line, the difference in the height of the annular bead between the metal gasket of the seventh embodiment and the conventional metal gasket appears in the same manner as the difference in the height of the restored bead. Yes.

  As is apparent from FIG. 12, when the step adjusting plate 3 having the step of 100 μm is provided, the conventional metal gasket G1 is more than the metal gasket G2 of the seventh embodiment at the specified axial force BF1. The annular bead pressing load is slightly large. This is because the conventional metal gasket G1 compresses and deforms the annular bead to a nearly flat shape, but the difference in this pressing load is subtle, and the step adjustment plate of the metal gasket G2 of the seventh embodiment. When the level difference H of 3 is increased to 120 μm, the annular bead pressing load is generally larger than that of the conventional metal gasket G1 as indicated by a one-dotted line in the figure, and the annular bead pressing load is ΔF1 at the prescribed axial force BF1. It becomes clearly larger than the conventional metal gasket G1. That is, the difference in the pressing load remains within a range that can be sufficiently compensated by the change in the level difference H due to the thickness change of the level difference adjusting plate 3.

  Accordingly, the cylinder head metal gasket 1 of the seventh embodiment can provide the same effects as those of the first embodiment, and in addition, the step adjustment plate 3 is provided with each cylinder hole 2a of the substrate 2. Therefore, the amount of compressive deformation of the inner annular bead 2b can be further reduced, and the inner annular bead 2b can be more reliably prevented from sagging.

  FIGS. 13 to 15 are cross-sectional views at the same positions as in FIG. 2 showing the eighth to tenth embodiments of the cylinder head metal gasket according to the present invention. Since the cylinder head metal gasket 1 of the embodiment includes the same substrate 2 as in the previous first embodiment, as in the seventh embodiment, the following mainly describes the seventh embodiment. The differences will be described.

  The cylinder head metal gasket 1 according to the eighth embodiment shown in FIG. 13 includes the two substrates 2 and a step adjusting plate 3 interposed between them. 3 has a plurality of holes 3c corresponding to the cooling water holes 2d, the lubricating oil holes 2g, and the bolt holes 2f of the respective substrates 2 in the same manner as the main part 3d in the seventh embodiment. However, the step adjusting plate 3 in the eighth embodiment has substantially the same outer peripheral contour shape as that of the substrate 2 as in the third embodiment, but up to the position of each cylinder hole 2a of the substrate 2. A sub-plate 4 that does not extend radially inward and ends within the range of the recess 2f of the double annular beads 2b, 2c of the substrate 2, and a recess formed by the double annular beads 2b, 2c of the substrate 2 A grommet plate 6 that is folded back within the range of 2f and is superimposed on both sides of the sub-plate 4 within the range of the recess 2f. The grommet plate 6 and the portion of the sub-plate 4 that overlaps the grommet plate 6 In this embodiment, the overlapping portion 3b is configured. Here, the grommet plate 6 can be formed in the same manner as the grommet portion 3e in the seventh embodiment, although it is made of a material plate separate from the sub plate 4.

  The cylinder head metal gasket 1 of the ninth embodiment shown in FIG. 14 includes a single substrate 2 and a step adjusting plate 3 along the recess 2f side of the substrate 2. The level difference adjusting plate 3 is configured similarly to the level difference adjusting plate 3 in the seventh embodiment shown in FIGS.

  A cylinder head metal gasket 1 according to the tenth embodiment shown in FIG. 15 includes a single substrate 2 and a step adjusting plate 3 along the recess 2f side of the substrate 2. The step adjustment plate 3 is configured in the same manner as the step adjustment plate 3 in the eighth embodiment shown in FIG.

  The cylinder head metal gaskets 1 according to the eighth to tenth embodiments can provide the same effects as those of the seventh embodiment, and in addition, according to the eighth and tenth embodiments. For example, since the grommet plate 6 superimposed on both sides of the sub-plate 4 is provided, the step H can be further increased. According to the ninth embodiment, the substrate 2 is a single piece, and the step adjustment plate 3 is also provided. Since it can be originally formed from one material plate, a metal gasket having low cost and excellent sealing durability 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 example. For example, the thicknesses of the sub-plate 4 and the shim plate 5 or the grommet plate 6 constituting the step adjustment plate 3 The combination of the materials and thicknesses of the substrate 2 and the level difference adjusting plate 3 may be appropriately changed as necessary.

  Thus, according to the cylinder head metal gasket of the present invention, it is possible to achieve a high sealing performance against the combustion gas in the cylinder bore, and to maintain the spring characteristics of the annular bead over a long period of time and to provide a predetermined surface on the deck surface. By maintaining the spring characteristics of the annular bead, the balance between the axial force of the tightening bolt and the pressing load of the annular bead at the time of initial fastening does not collapse after that, Since the axial force does not decrease, the high sealing performance can be reliably maintained in the long term.

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 II-II line | wire of FIG. 1 of the metal gasket of the said 1st Example. (A), (b) is the same position as FIG. 2, showing the metal gasket of the first embodiment inserted between a cylinder block and a cylinder head of an internal combustion engine and tightened with a tightening bolt. It is sectional drawing in and a principal part expanded sectional view. It is sectional drawing in the position similar to FIG. 2 which shows the structure of 2nd Example of the metal gasket for cylinder heads of this invention. It is sectional drawing in the position similar to FIG. 2 which shows the structure of 3rd Example of the metal gasket for cylinder heads of this invention. It is sectional drawing in the same position as FIG. 2 which shows the structure of 4th Example of the metal gasket for cylinder heads of this invention. It is sectional drawing in the same position as FIG. 2 which shows the structure of 5th Example of the metal gasket for cylinder heads of this invention. It is sectional drawing in the same position as FIG. 2 which shows the structure of 6th Example of the metal gasket for cylinder heads of this invention. It is sectional drawing in the same position as FIG. 2 which shows 7th Example of the metal gasket for cylinder heads of this invention. (A) is the cross section in the same position as FIG. 9 which shows the metal gasket for cylinder heads of the said 7th Example in the state which is inserted between a cylinder block and a cylinder head, but is not clamp | tightened with a bolt. FIGS. (B) and (c) show the seventh embodiment of the cylinder head metal gasket inserted between the cylinder block and the cylinder head and tightened with a tightening bolt, similar to FIG. It is sectional drawing in this position, and the principal part expanded sectional view. It is a characteristic view which shows the relationship between the press load measured about the metal gasket for cylinder heads of the said 7th Example, and the conventional metal gasket for cylinder heads, and a restored bead height. It is a characteristic view which shows the relationship between the fastening load (axial force) of the fastening bolt measured about the metal gasket for cylinder heads of the said 7th Example, and the conventional metal gasket for cylinder heads, and the press load of an annular bead. It is sectional drawing in the same position as FIG. 2 which shows the structure of 8th Example of the metal gasket for cylinder heads of this invention. It is sectional drawing in the same position as FIG. 2 which shows the structure of 9th Example of the metal gasket for cylinder heads of this invention. It is sectional drawing in the same position as FIG. 2 which shows the structure of 10th Example of the metal gasket for cylinder heads of this invention. It is sectional drawing which illustrates the structure of the conventional metal gasket for cylinder heads.

Explanation of symbols

1 Metal gasket for cylinder head 2 Substrate
2a Cylinder hole
2b, 2c annular bead
2d cooling water hole
2e peripheral bead
2f recess
2g annular bead
2h Bolt hole
2i Lubricating oil hole 3 Step adjustment plate
3a Cylinder hole
3b Polymerization part
3c hole
3d main part
3e Folded part 4 Sub-plate 5 Shim plate 6 Grommet plate 7 Cylinder block
7a cylinder bore
7b Cooling water jacket 8 Cylinder head
8a Cooling water hole 9 Tightening bolt

Claims (7)

Cylinder hole (2a) formed corresponding to each cylinder bore of the cylinder block of the internal combustion engine, and a single bevel-shaped cross section formed around each cylinder hole in opposite directions and spaced apart from each other in the radial direction A double annular bead (2b, 2c) having a shape, and a cooling water hole (2d) formed in the outer periphery of each annular bead corresponding to the cooling water jacket of the cylinder block and the cooling water hole of the cylinder head And at least one substrate (2) made of a metal plate, having an outer peripheral bead (2e) having a one-sided cross-sectional shape formed at a position surrounding the annular bead and the cooling water hole as a whole,
The substrate (2) has an annular overlapping portion (3b) located in the range of the recess (2f) formed by the double annular beads (2b, 2c) and facing the recess, A level difference adjusting plate (3) made of a metal plate, which is overlapped and extends at least from the overlapped portion to the position of the outer peripheral edge of the substrate (2);
A metal gasket for cylinder heads. The step adjustment plate (3)
A sub-plate (4) extending from the range of the recess (2f) formed by the double annular beads (2b, 2c) of the substrate (2) to the position of the outer peripheral edge of the substrate (2);
The substrate (2) extends radially outward from a position radially inward of the double annular beads (2b, 2c) to a range of the recess (2f) formed by the double annular beads. A shim plate (5) which is overlapped and fixed to the sub-plate (4) within the range of the concave portion and constitutes the overlapping portion (3b);
The metal gasket for a cylinder head according to claim 1, characterized by comprising: The step adjustment plate (3)
A sub-plate (4) extending from a position radially inward of the double annular bead (2b, 2c) of the substrate (2) to a position of an outer peripheral edge of the substrate (2);
The overlapping portion (3b) is overlapped and fixed to the sub-plate (4) so as to be positioned within the range of the concave portion (2f) formed by the double annular beads (2b, 2c) of the substrate (2). At least one shim plate (5) constituting
The metal gasket for a cylinder head according to claim 1, characterized by comprising: The step adjustment plate (3)
A sub-plate (4) extending from the range of the recess (2f) formed by the double annular beads (2b, 2c) of the substrate (2) to the position of the outer peripheral edge of the substrate (2);
The overlapping portion (3b) is overlapped and fixed to the sub-plate (4) so as to be positioned within the range of the concave portion (2f) formed by the double annular beads (2b, 2c) of the substrate (2). At least one shim plate (5) constituting
The metal gasket for a cylinder head according to claim 1, characterized by comprising: The step adjustment plate (3)
A main portion (3d) extending from the range of the recess (2f) formed by the double annular beads (2b, 2c) of the substrate (2) to the position of the outer peripheral edge of the substrate (2);
The main part (3a) is folded back from the main part (3d) within the range of the concave part (2f) formed by the double annular beads (2b, 2c) of the substrate (2). A grommet part (3e) that is superimposed on the superimposing part (3b) and
The metal gasket for a cylinder head according to claim 1, characterized by comprising: The step adjustment plate (3)
A sub-plate (4) extending from the range of the recess (2f) formed by the double annular beads (2b, 2c) of the substrate (2) to the position of the outer peripheral edge of the substrate (2);
The overlap portion is folded back within the range of the recess (2f) formed by the double annular beads (2b, 2c) of the substrate (2) and overlapped with the sub-plate (4) within the range of the recess. A grommet plate (6) constituting (3b);
The metal gasket for a cylinder head according to claim 1, characterized by comprising: The substrate (2) is provided with two sheets such that the recesses (2f) formed by the double annular beads (2b, 2c) face each other,
The metal gasket for cylinder head according to any one of claims 1 to 6, characterized in that the step adjustment plate (3) is located between the substrates (2).

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