JP2006342749A - Metal gasket - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a metal gasket used for an engine of an open deck structure and the like improving durability by preventing wear and crack, and securing stable sealing performance for a long period of time. <P>SOLUTION: In the metal gasket made of a metal base plate provided with a cooling liquid passage W opening along an outer circumference of the cylinder bore C on a joining surface, installed between joining surfaces of a cylinder block 21 and a cylinder head 20 and sealing a part between the joining surfaces, and provided with a bore bead 7 surrounding a cylinder bore 3 corresponding to the cylinder bore C and an outer circumference bead 8 surrounding an outer circumference edge part of the cooling liquid passage W, the base plate 2 is provided with an intermediate bead 10 in a non-contact surface zone A of the cylinder block 21 and the cylinder head 20 at an opening part of the cooling liquid passage W. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a metal gasket used for sealing a joint between an engine cylinder block and a cylinder head.

  Conventionally, a cylinder hole corresponding to a cylinder bore is surrounded by a substrate made of an elastic metal plate at a joint portion between a cylinder block and a cylinder head constituting an engine in order to improve sealing performance of a joint surface between the cylinder block and the cylinder head. A plurality of substrates on which inner (bore) beads are formed and hole (outer circumference) beads surrounding the periphery of the tightening bolt holes, oil holes, and cooling water holes arranged around the cylinder holes are formed. A laminated metal gasket is known (for example, Patent Document 1).

In addition, in a metal gasket used in an engine such as an open deck structure provided with a coolant passage that continuously opens along the periphery of the cylinder bore, the substrate is deformed at the opening portion of the coolant passage, or the compression force and tensile force are increased. Due to the force acting alternately, deformation is further increased, and cracks may occur in the substrate due to the influence of engine vibration. A metal gasket has been proposed in which a reinforcing portion is provided at a portion facing the opening to increase rigidity and prevent the substrate from being deformed, wrinkled, or cracked (Patent Document 2).
JP-A-6-58417 JP-A-9-303560

  In the open deck type engine as described above, when a metal gasket is applied to the joint surface between the cylinder head and the cylinder block, the gasket is placed on one or both surfaces of the cylinder head and the cylinder block corresponding to the coolant passage. There is a non-joint surface area that is not joined.

  As shown in FIG. 7, the portion of the conventional metal gasket 50 in the non-joint surface region A becomes a deformable region that is not sandwiched between the joint surfaces of the cylinder block 21 and the cylinder head 20, and the side of the gasket 50 is changed by engine operation. In the direction, stresses f1 and f2 are repeatedly applied in the opposite directions, and vertical vibration S is applied by the vertical movement of the piston, thereby causing fretting at the contact portion between the gasket 50 and the cylinder head 20 or the cylinder block 21. The substrate 51 and the bead portions 52 and 53 are worn out, and further, damage such as a crack is generated due to a fatigue phenomenon of the elastic metal plate, and the gap between the substrates 51 and 51 is shifted, so that the sealing performance is deteriorated and the durability of the gasket 50 is increased. There is a problem of reducing the sex.

  The present invention provides a metal gasket that is applied to an open deck engine or the like by providing a buffer portion that absorbs stress and fine vibration applied to the gasket in a non-joint surface region at the joint portion between the cylinder block and the cylinder head. An object of the present invention is to provide a metal gasket capable of preventing the wear and cracking of the gasket to improve durability and ensuring a stable sealing property over a long period of time.

  In the metal gasket of the present invention, a coolant passage that opens along the outer periphery of the cylinder bore is interposed between the joint surfaces of the cylinder block and the cylinder head provided on the joint surface to seal between the joint surfaces. A metal gasket comprising a substrate made of an elastic metal plate provided with a bore bead surrounding a cylinder hole corresponding to the cylinder bore and an outer circumferential bead surrounding an outer peripheral edge of the coolant passage. Is characterized in that an intermediate bead is provided in a non-joint surface area between the cylinder block and the cylinder head at the opening of the coolant passage.

  In the present invention, a plurality of the substrates may be laminated to form a metal gasket, and the intermediate bead may be formed to bulge toward the opening side of the coolant passage.

  Furthermore, in the metal gasket of the present invention, at least a part of the bulging portions of the intermediate beads may be formed so as to contact each other, and the intermediate beads provided on the respective substrates have different shapes and dimensions. It can also be formed.

  According to the metal gasket of the present invention, by using a substrate having an intermediate bead provided in a non-joint surface area between the cylinder block and the cylinder head in the opening of the coolant passage of the cylinder block, the intermediate bead is caused by the operation of the engine. Buffers and absorbs stress and micro-vibration applied to the gasket to suppress wear and cracking of the substrate body and bead part, and the reaction force of the intermediate bead due to tightening acts on the bore bead and outer peripheral bead to ensure the surface pressure of the bead part. And improve sealing performance. In addition, the improvement in the surface pressure of the bead portion reduces the stress on the cylinder bore wall by suppressing the vibration of the bead itself. Further, the intermediate bead increases the rigidity of the substrate in the non-joint surface area of the opening to prevent the deformation of the substrate during tightening.

  Furthermore, at least a portion of the bulges of the intermediate beads provided on the substrate are in contact with each other so that the displacement of the substrate during engine operation can be prevented, and in addition, the number of fixing points such as caulking when the substrates are stacked can be reduced. As a result, the assembly efficiency of the gasket can be improved.

  Embodiments of the present invention will be described below with reference to the drawings.

  1 is a plan view of a metal gasket according to an embodiment of the present invention, FIG. 2 is a cross-sectional view taken along line AA of FIG. 1, FIG. 2A is a trapezoidal shape 10 in a bead cross section, and FIG. An example in which the cross section is a semicircular shape 10 ′ is shown. FIG. 3 is a schematic cross-sectional view showing a state in which a metal gasket is interposed between the joint surfaces of an open deck engine cylinder block and a cylinder head and tightened with a tightening bolt.

  In general, a cylinder block of an open deck structure engine has a plurality of cylinder bores C arranged in a row in parallel and a cylinder block extending in the longitudinal direction of the cylinder block so as to surround the cylinder bores C on both sides of the row of cylinder bores C. It has a coolant passage W, a bolt hole into which a tightening bolt is screwed, and an oil circulation hole.

  In the figure, reference numeral 1 denotes a metal gasket. The metal gasket 1 corresponds to a cylinder bore C on a substrate 2 made of an elastic metal plate such as a stainless steel plate coated with a heat-resistant rubber or a resin containing molybdenum disulfide. A cylinder hole 3 is opened, and a plurality of tightening bolt holes 4, a cooling water hole 5, and an oil hole 6 are formed around the cylinder hole 3.

  A bore bead 7 made of a full bead that bulges toward the outside of the substrate 2 as shown in FIG. 2A is formed around the cylinder hole 3 so as to seal the cylinder hole 3. Thus, it is formed so as to prevent the leakage of gas and the intrusion of cooling water.

  An outer peripheral bead 8 made of a half bead bulging outwardly surrounding the cooling liquid passage W is provided between the outer peripheral edge of the substrate 2 at the outer peripheral portion of the cooling liquid passage W, and seals the inner side of the gasket 1 for cooling. While preventing leakage of water and oil to the outside, it prevents entry of moisture and dust from the outer periphery.

  Further, the portion of the substrate 2 corresponding to the opening of the coolant passage W of the cylinder block 21 between the bore bead 7 and the outer peripheral bead 8 is an intermediate made of a full bead that bulges toward the cylinder block 21 that surrounds the bore bead 7. A bead 10 is formed. As shown in the figure, the intermediate bead 10 is discontinuously provided at the narrow portion 3 a between the cylinder holes 3 and 3 arranged in parallel and the portion overlapping the cooling water hole 5.

  The cylinder hole 3, the tightening bolt hole 4, the cooling water hole 5, and the oil hole 6 and the bore beads 7, the outer peripheral beads 8, and the intermediate beads 10 are formed by press molding the substrate 2. The two substrates 2 and 2 are stacked and fixed by caulking at the fixing portion 11 at the peripheral edge.

  Here, the full bead is a bead 27 having a cross-sectional mountain shape as shown in FIG. 8A and a cross-sectional shape bulging from the substrate surface, and the half bead is a slope-like slope on one side as shown in FIG. 8B. A bead 28 having a cross-sectional shape that bulges with the shape of a bead.

  The metal gasket 1 of the present embodiment is configured by laminating two substrates 2 and 2 shown in FIG. 2A with a metal reinforcing plate 9 interposed therebetween, and the bore bead 7 and the outer peripheral bead 8 are formed at the bead bulging portion. The seals of the joint surfaces of the gasket 1 are ensured so that the directions are opposite to each other, and the intermediate beads 10 are directed toward the cylinder block 21 so that their bulges engage with each other in an overlapping manner. The bulge is formed.

  As shown in FIG. 3, when the metal gasket 1 is interposed between the cylinder block 21 and the cylinder head 20 and is tightened with a fastening bolt, the metal gasket 1 is pressed between the cylinder block 21 and the cylinder head 20 and 2. The flat surface portions of the substrates 2 and 2 are in close contact, the bore bead 7 seals the cylinder bore C, and the outer peripheral bead 8 seals the inner side of the gasket 1.

  In the open deck type engine, the coolant passage W is provided in the joint surface 22 of the cylinder block 21 along the outer periphery of the cylinder bore C. Therefore, as shown in the figure, the gasket 1 surrounds the cylinder bore C. In the portion corresponding to the coolant passage W between the bore bead 7 and the outer peripheral bead 8, there is a non-joint surface area A where the gasket 1 does not contact the joint between the cylinder block 21 and the cylinder head 20. The intermediate bead 10 is positioned between the cylinder block 21 and the cylinder head 20 in the non-joint surface area A.

  The intermediate bead 10 in the non-joint surface area A is in a non-contact state with the cylinder block 21 and the cylinder head 20, and a certain amount of movement is allowed between the bore bead 7 and the outer peripheral bead 8. Since the bulging portion exerts an action of buffering stress and vibration, the laterally opposite stresses f1 and f2 repeatedly generated by the operation of the engine on the non-joint surface region A of the gasket 1 and the vertical movement due to the vertical movement of the piston. By buffering the vibration S in the direction, the stress and vibration are absorbed.

  As a result, the fatigue phenomenon of the elastic metal plate due to the accumulation of stress strain in the gasket 1 and the repeated vibration is suppressed, and the occurrence of damage such as cracks and breakage of the substrate 2 is prevented, and the gasket 1 and the cylinder head 20 or the cylinder block 21 are prevented. Thus, fretting can be reduced at the contact portion to prevent the substrate 2 body and the bead portions 7 and 8 from being worn, and the sealing performance of the gasket 1 can be secured and the durability can be improved.

  In order to obtain the above buffer effect, the intermediate bead 10 is formed in a non-contact state with the cylinder block 21 and the cylinder head 20.

  Further, a reaction force is generated in the intermediate bead 10 that is allowed to move by tightening with the tightening bolt, and this reaction force acts on the bore bead 7 and the outer peripheral bead 8 to increase the surface pressure of the bead portion and improve the sealing performance. .

  Further, since the bulging portions of the intermediate beads 10 provided on the substrate 2 are in contact with each other, the displacement between the substrates 2 and 2 during engine operation is prevented and the sealing performance of the gasket 1 is maintained. By preventing the displacement, it becomes possible to reduce the fixing portion 11 such as caulking processing between the substrates 2 and 2 when the gasket 1 is laminated, and the assembly processing efficiency of the gasket 1 can be improved.

  Further, the intermediate bead 10 has an action of increasing the rigidity of the substrate 2 in the non-bonding surface area A, and an effect of preventing deformation in the non-bonding surface area A of the substrate 2 at the time of fastening is also obtained.

  And, by improving the sealing property and durability, it is possible to reduce the number of laminated metal gaskets, thereby reducing the cost of the metal gaskets.

  As shown in FIG. 4, the metal gasket of the present invention may be a gasket 12 made of a single substrate. Further, as shown in FIG. 5, the intermediate bead 14 may be a gasket 13 bulged toward the cylinder head 20, and in this case, an interval K is provided so that the upper end portion 14 a of the bead 14 does not contact the cylinder head 20. Will be implemented.

  In addition, in a metal gasket formed by laminating a plurality of substrates, it can be usually performed by superimposing substrates 2 and 2 formed with the same cross-sectional shape of the intermediate bead 10 as shown in FIG. Using the same shape of the substrate can reduce the cost of the substrate mold and improve the assembling efficiency because the bead orientation is the same during the lamination process.

  On the other hand, FIG. 6 is a view showing another example of a gasket having a laminated structure of a plurality of substrates (in the figure, two substrates), and intermediate beads 15 and 16 having different sizes and shapes for each substrate to be laminated. A metal gasket 19 having In this way, the gasket 19 using different bead shapes is not bonded to the substrates 17 and 18 at the time of use due to factors such as the material and thickness of the substrates 17 and 18 used, or the dimensions and shapes of the bore beads 7 and the outer peripheral beads 8. This is effective when the deformation amounts in the surface region A are different from each other. Also in this case, it is preferable that the bulging portions of the intermediate beads 15 and 16 are in contact with each other at one or more locations, and displacement of the substrates 17 and 18 during engine operation can be prevented.

  In the above embodiment, the cross-sectional shape of each intermediate bead has been described with the trapezoidal cross-section shown in FIG. 2A. However, the intermediate bead has a semicircular cross-section as shown in FIG. A semi-elliptical shape, or a bead having one of the slopes linear and the other curved is used, and the cross-sectional shape of the intermediate bead is not limited at all.

  For example, in the case where two substrates shown in FIG. 9 are laminated, an intermediate bead 10a (FIG. 9 (FIG. 9)) is formed with trapezoidal cross-section full beads 31 and 31 that swell in the vertical direction with the flat portion 32 interposed therebetween. a)) An intermediate bead 10b (FIG. 9B) in which a full bead 33, 33 having a small bulging amount in the vertical direction is formed with an interval between the flat portions 34, and a trapezoidal cross section that bulges in the vertical direction. Intermediate beads 10c (FIG. 9 (c)) in which the full beads 35, 35 are continuously formed in a substantially S-shaped cross section at the slope portion 36, and full beads 37, 38 having different bulging amounts in the vertical direction are continuously provided. Also in the formed asymmetrical intermediate bead 10d (FIG. 9D) and the intermediate beads 10a, 10b, and 10c, full beads 31, 31, 33, 33, 3, which protrude in the vertical direction, respectively. It can be varied from each other bulge height of 35 such as formed in the intermediate bead asymmetrically shaped, adopting an intermediate bead of various cross-sectional shapes.

  The metal gasket of the present invention can be used as a sealing material for an internal combustion engine such as an automobile engine, but is particularly suitable for an engine employing an open deck structure, a semi-open deck structure, a wet liner structure, or the like.

It is a top view of the metal gasket which concerns on embodiment. It is the sectional view on the AA line of FIG. It is sectional drawing which shows the use condition which fastened the metal gasket between the joint surfaces of a cylinder block and a cylinder head. It is sectional drawing which shows the use condition of another gasket. It is sectional drawing which shows the use condition of the gasket of another 2nd example. It is sectional drawing which shows the use condition of the gasket of another 3rd example. It is sectional drawing which shows the use condition of the gasket of a prior art example. It is a bead sectional view explaining a bead shape. It is a bead sectional view explaining each embodiment of an intermediate bead.

Explanation of symbols

1 ... Metal gasket 2 ... Substrate 3 ... Cylinder hole 7 ... Bore bead 8 ... Outer circumferential bead 10 ... Intermediate bead 20 ... Cylinder head 21 ... Cylinder block A ... Non-joint area C ... Cylinder bore W ... Coolant passage

Claims (5)

A metal gasket in which a coolant passage opening along the outer periphery of the cylinder bore is interposed between the joint surfaces of the cylinder block and the cylinder head provided on the joint surface, and seals between the joint surfaces, In a metal gasket comprising a substrate made of an elastic metal plate provided with a bore bead surrounding a cylinder hole corresponding to a cylinder bore and an outer circumferential bead surrounding an outer peripheral edge of the coolant passage,
The metal gasket, wherein the substrate is provided with an intermediate bead in a non-joint surface area between the cylinder block and the cylinder head in the opening of the coolant passage. The metal gasket according to claim 1, wherein a plurality of the substrates are laminated. The metal gasket according to claim 1 or 2, wherein the intermediate bead is formed to bulge toward the opening side of the coolant passage. The metal gasket according to claim 2 or 3, wherein at least a part of the bulging portion of the intermediate bead is in contact with each other. The metal gasket according to any one of claims 2 to 4, wherein the intermediate beads provided on each of the substrates are formed with different shapes and dimensions.

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