JP2005016552A - Metal gasket - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a metal gasket capable of preventing liquid leakage from a three-surface joining part 70 of a cylinder block, a cylinder head and a chain case cover with a simple configuration. <P>SOLUTION: A metal gasket is used for an engine in which a cylinder block and a cylinder head are joined with each other via the metal gasket, and a chain case cover is assembled to side surfaces of the cylinder block and the cylinder head to form a chain chamber. A bead 5 extends along the chain chamber 61 on a substrate 2 consisting of a thin-walled metal plate to constitute the metal gasket, and an end part of the bead in the extending direction extends to a chain case cover joining surface 60a. An expanding elastic body 12 formed of an elastic seal material which expands outward of at least the side surfaces of the cylinder block and the cylinder head and is abutted on the joining surface of the chain case cover is provided on the end part of the bead in the extending direction. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a metal cylinder head gasket inserted between a cylinder block and a cylinder head constituting an engine.
[0002]
[Prior art]
In general, leakage of combustion gas, cooling water, lubricating oil, etc. from the joint surface between the cylinder block and the cylinder head mounted on the cylinder block, which is a component of an automobile engine or other engine, is prevented. For this purpose, various cylinder head gaskets are interposed.
[0003]
As a metal gasket, conventionally, an uneven bead is formed on a thin metal plate having rigidity and elasticity, and a heat-resistant sealing material film is applied on both sides of the substrate to a thickness of 20 to 30 microns. Gaskets are known. For example, the metal gasket described in Patent Document 1 forms a substrate from a rigid thin plate metal such as a stainless steel plate, and opens various holes such as a combustion chamber hole, a bolt hole, and an oil hole to the substrate. At the same time, the periphery of the hole that needs to be sealed is surrounded by a metal bead made of full beads and sealed. In addition, repeated stress due to vibration amplitude generated by engine operation is input to the metal gasket. In order to prevent bead fatigue failure due to the repeated stress, a thickened portion that suppresses deformation in the plate thickness direction of the bead ( Stopper) is provided.
[0004]
By the way, in recent years, due to rapid technological innovation of internal combustion engines, developments such as reduction in size and weight, high output, and fuel saving have progressed. For example, the number of valves is 4 to 4 per cylinder per conventional one. Increase the number of camshafts to 5 and increase the number of camshafts to operate this valve to 2 compared to the conventional one, and improve the intake efficiency and exhaust efficiency by rotating the camshaft at a high speed. Is possible. As a method for rotating the camshaft, a belt driving method that generally has a low noise during driving and does not require a refueling operation has been conventionally used. However, the timing belt used in the belt driving method is durable against high loads. In recent years, since the noise of the drive shaft has been reduced due to the improvement of the chain, in recent years, there has been a tendency to adopt an engine using a chain drive system.
[0005]
In the chain drive system, it is necessary to appropriately lubricate the chain in order to maintain good driving. For this reason, in a chain drive type engine, when the cylinder block 50 and the cylinder head 40 and the chain case cover 60 are manufactured separately in order to prevent scattering of oil and to reduce noise during driving as much as possible. (See FIG. 1).
[0006]
At this time, the cylinder block 50 is usually of a type in which cast iron is used as a raw material, or a type in which the cylinder block body is cast with aluminum only with a cast iron sleeve around the cylinder bore. A cylinder head 40 is stacked on the cylinder block 50 with the gasket 1 interposed therebetween, and further, a chain case cover 60 having a U-shaped cross section that covers a chain that drives a camshaft projecting upward from the cylinder head. Are attached in contact with the side surfaces of the assembled cylinder block 50 and cylinder head 40. In addition, each component is mutually joined by being fastened with a fastening bolt.
[0007]
[Patent Document 1]
Japanese Utility Model Publication No. 63-180769 [0008]
[Problems to be solved by the invention]
Here, the chain case cover 60 is made of aluminum. Further, when the cylinder head 40 is made of aluminum having a thermal expansion coefficient larger than that of the cast iron cylinder block 50, the metal gasket 1 has a small thermal expansion in consideration of the difference in the amount of thermal expansion deformation. The outer diameter is set equal to or less than the size of the cylinder block. That is, there are many arrangement configurations in which the outer peripheral end face position of the metal gasket is located slightly inside the side face positions of the cylinder block and the cylinder head. Accordingly, a gap due to the minus portion of the gasket dimension is generated in the three-surface joint portion 70 of the cylinder block, the cylinder head, and the chain case cover sandwiching the cylinder head gasket, and the three-surface joint portion 70 of the three parts is operated. A gap is generated due to a difference in thermal expansion of each part that occurs sometimes, and the gap changes every time the engine is operated or stopped.
[0009]
On the other hand, in the past, a liquid sealing material is applied to the gap of the three-surface joint portion 70 at the time of assembling, but this sealing material is poor in following the volume change. In other words, the gap always changes due to the thermal change of engine operation / stop, especially the gap becomes the maximum space volume at high temperature, whereas the sealing material applied when the engine is cold has the ability to follow the volume change. Since it is scarce, oil leakage may occur from the three-surface joint 70.
The present invention has been made in consideration of the above problems, and a metal gasket capable of preventing liquid leakage from the three-surface joint portion of the cylinder block, the cylinder head, and the chain case cover with a simple configuration. The issue is to provide.
[0010]
[Means for Solving the Problems]
In order to solve the above-described problems, the present invention provides a cylinder block and a cylinder head that are joined via a metal gasket, and a chain case cover is assembled to the side surface of the cylinder block and the cylinder head. The metal gasket used in an engine having a configuration in which a chain chamber is formed by a side surface of a head and an inner surface of a chain case cover,
A thin metal plate is used as a substrate, and a bead extends along the chain chamber at an edge of the substrate on the chain case cover side, and an end portion of the bead extends in the cylinder block and the cylinder head. In the metal gasket extending toward the chain case cover joint surface that joins the side surface,
The chain case cover protrudes outward from at least the side surfaces of the cylinder block and the cylinder head by being compressed with respect to the end portion in the extending direction of the bead at the joint surface facing the cylinder block and the cylinder head. An overhanging elastic body made of an elastic sealing material that is brought into contact with the joint surface and is compressed in the gap between the three-surface joint portions is provided.
[0011]
Next, in the invention described in claim 2, in the configuration described in claim 1, the bead includes a metal bead formed by bending a substrate in a plate thickness direction and forming a convex shape, and the metal bead. A rubber bead made of an elastic sealing material that is fixed to the convex side surface and filled in the concave part on the back side of the convex part and compressively deforms in the plate thickness direction along with the deformation of the metal bead, and further, The rubber beads are integrally formed.
[0012]
Next, the invention described in claim 3 is a thickening made of a material having higher rigidity than the elastic sealing material, which restricts the amount of elastic deformation of the bead on the substrate relative to the invention described in claim 2. This is characterized in that a portion is provided.
Next, the invention described in claim 4 is the configuration described in claim 2 or claim 3, wherein the metal bead extends to a position where the overhanging elastic body is disposed, and enters the overhanging elastic body. In addition to being embedded, the embedded portion of the metal bead has a notch opened to the chain case cover joint surface side.
Next, the invention described in claim 5 is different from the structure described in claim 4 in that the metal bead has a wider bead width at a position embedded in the overhanging elastic body than other portions. It is characterized by being set.
[0013]
DETAILED DESCRIPTION OF THE INVENTION
Embodiments of the present invention will be described below with reference to the drawings.
As shown in FIG. 1, an engine in which the present metal gasket 1 is employed has a cylinder head 40 laminated on the cylinder block 50 via the metal gasket 1, and the cylinder block 50 and the cylinder head 40. A chain case cover 60 having a U-shaped cross section is assembled to the side surfaces 50 a and 40 a of the cylinder chamber 50, and the chain chamber 61 is formed by the side surfaces 50 a and 40 a of the cylinder block 50 and cylinder head 40 and the inner surface of the chain case cover 60. Intended for the structure to be formed. Each part is fixed with a fastening bolt.
[0014]
The metal gasket 1 constituting the cylinder head gasket has a thin metal plate as a substrate 2, and the substrate 2 is provided with openings such as combustion chamber holes 20, water holes, oil holes, bolt holes 21 and the like. In addition, a bead is formed along the periphery of each opening that requires sealing to seal the outer periphery of the opening.
Further, the edge 2a on the chain case cover 60 side of the outer periphery of the substrate 2 is arranged along the chain chamber 61 in order to seal the outer periphery of the chain chamber 61 in which the chain is disposed, as shown in FIG. As shown in FIGS. 2 and 3, the bead 5 extends at both ends 3 in the extending direction of the bead 5, and the chain case cover 60 is in contact with the side surfaces of the cylinder block 50 and the cylinder head 40. It extends toward the surface 60a. A broken line 10a in FIG. 3 indicates the boundary position of the metal bead 10 in the bead width direction. Reference BD indicates a bead line.
[0015]
In the present embodiment, as shown in FIGS. 4 and 5, the bead 5 includes a metal bead 10 formed by bending the substrate 2 in the thickness direction and forming a convex shape, and a convex side of the metal bead 10. The rubber beads 11 are made of elastic sealing materials 11b and 11a that are fixed to the surface and filled in the concave portions on the back side of the convex portions and compressively deformed in the thickness direction along with the deformation of the metal beads 10. In the present embodiment, the surface of the elastic sealing material 11a filled in the concave portion is set flush with the lower surface of the substrate 2, and the elastic sealing material 11b fixed to the convex portion side is equivalent to the protruding height of the metal bead 10. The height is set to be slightly wider than the bead width of the metal bead 10.
[0016]
And the bead 5 which consists of the said metal bead 10 and the rubber bead 11 is formed to the 2b end surface position of the board | substrate 2 which opposes the said chain case cover joining surface 60a. At the end portion 3 of the bead 5 in the extending direction, the overhanging elastic body 12 is configured by setting the height of the rubber bead 11 to be higher than the other portions.
[0017]
Here, the rubber bead portion constituting the overhanging elastic body 12 has a bead height higher than that of the other portion, that is, is set to be thick, but may escape to the outside during compression compared to the other portion. It is possible to prevent compression failure. Further, the height of the metal bead 10 embedded in the overhanging elastic body 12 may be made relatively low to increase the amount of the upper elastic sealing material 11b. Further, the elastic sealing materials 11a and 11b are made of sealing materials having heat resistance and elasticity. For example, a rubber material such as fluoro rubber, NBR, or silicon rubber, or a resin material may be used.
[0018]
Further, the substrate 2 is provided with a thickened portion 9 in the vicinity of the end portion 3 in the extending direction of the bead 5 so as to regulate the amount of compressive deformation of the bead 5. As shown in FIG. 4, the thickened portion 9 of the present embodiment is an example in which the end portion of the substrate 2 is formed by bending the upper side, but if it is realized by a known means such as attaching a grommet, Good.
In addition, the outer periphery of the opening that needs to be sealed such as the combustion chamber hole 20 is also sealed with a bead.
[0019]
Next, operations and effects of the metal gasket 1 having the above-described configuration will be described.
The metal gasket 1 is inserted between the opposing joint surfaces 60a of the cylinder block 50 and the cylinder head 40, and the cylinder block 50 and the cylinder head 40 are tightened with tightening bolts. A seal pressure is generated and a seal is realized along the chain chamber 61, so that oil or the like is prevented from entering the cylinder block 50 and the cylinder head 40 from the chain chamber 61. Further, the intrusion of liquid or the like on the opposite side is also prevented.
[0020]
Here, since the bead 5 of this embodiment is a structure which generate | occur | produces a required sealing pressure with the synthetic | combination spring by the metal bead 10 and the rubber bead 11 which were compressively deformed, the hardness of the board | substrate 2 which comprises the metal bead 10 is equivalent to that. It is possible to lower. Further, the portion of the bead 5 that comes into contact with both the upper and lower joint surfaces (seal surface) becomes the flat surface portion of the soft elastic sealing material 11a, 11b that has been compressed and deformed, and the soft elastic sealing material 11a, 11b abuts. Fill the engine tool mark on the joint area. For this reason, for example, even if the pulsating pressure is caused by engine operation, the elastic sealing materials 11a and 11b can follow and completely seal.
[0021]
Further, at the end portion 3 of the bead 5 in the extending direction, the elastic seal members 11a and 11b are made thicker than the other portions, so that the overhang made of the elastic seal members 11a and 11b is secured by bolt tightening. As shown in FIGS. 6A to 6B, the elastic body 12 is compressed and deformed and protrudes at least toward the chain case cover joint surface 60a and comes into contact with the joint surface 60a. As a result, the gap between the three-surface joint portion 70 formed by the three parts of the cylinder block 50, the cylinder head 40, and the chain case cover 60 is filled and sealed by the overhang portion due to the deformation of the overhang elastic body 12. Thus, leakage of oil from the three-surface joint portion 70 can be prevented.
[0022]
Further, when the cylinder block 50 and the cylinder head 40 are thermally expanded due to the heat generated by the engine operation, the amount of deformation due to the difference in the coefficient of thermal expansion of the cylinder block 50 and the cylinder head 40 is different. Although changing, the overhanging elastic body 12 follows the change and seals in a state where the gap is always filled. That is, the overhanging portion of the overhanging elastic body 12 is not affected even when the gap between the three-surface joint portion 70 is temporarily formed in the vertical direction due to the difference in thermal expansion between the cylinder block 50 and the cylinder head 40. Following the formation of the gap in the vertical direction, it deforms up and down and fills in a compressed state, and the overhanging portion of the overhanging elastic body 12 is restored following the change in the direction in which the gap decreases.
[0023]
Here, in the said embodiment, although the case where the bead 5 is the synthetic bead 5 of the metal bead 10 and the rubber bead 11 is illustrated, it is not limited to this. The bead 5 may be composed of only the metal bead 10, and the elastic sealing materials 11 a and 11 b as the overhanging elastic body 12 may be provided only at the extending direction end 3 of the bead 5. However, in this case, it is necessary to increase the tightening load in order to ensure a reliable seal, or to set the rigidity of the substrate 2 higher than that of the substrate 2 of the above embodiment. Further, since the elastic sealing materials 11a and 11b as the overhanging elastic body 12 are deformed so as to escape to the side opposite to the chain case cover joint surface 60a side (inside the substrate 2) when compressively deformed, the chain The amount of deformation that protrudes toward the case cover joint surface 60a is reduced, and accordingly, the structure is disadvantageous compared to the above embodiment.
[0024]
Further, in the above embodiment, the case where the elastic body 12 for overhanging is configured by increasing the thickness of the upper side (projection side) of the rubber bead 11 is illustrated, but the lower side (inside the recess) of the rubber bead 11 is increased. The overhanging elastic body 12 may be formed by increasing the thickness or by increasing the thickness of the upper and lower elastic sealing materials.
Moreover, although the case where the thickening part 9 is provided is illustrated in the said embodiment, when the tightening load can be set small, the thickening part 9 may be omitted.
[0025]
Next, a second embodiment will be described with reference to the drawings. The same members as those in the first embodiment will be described with the same reference numerals.
The basic configuration of the second embodiment is the same as that of the first embodiment, except that the configuration of the end portion 3 of the bead 5 in the extending direction, that is, the structure of the overhanging elastic body 12 is different.
That is, in this embodiment, as shown in FIG. 7 to FIG. 9, the chain case of the metal bead 10 portion that is located in the extending direction end 3 of the bead 5 and is embedded in the overhanging elastic body 12. A notch 15 opened on the cover 60 side is provided, whereby the upper and lower elastic sealing materials 11a and 11b (the overhanging elastic body 12) sandwiching the substrate 2 are integrated.
[0026]
By doing in this way, the thickness of the overhanging elastic body 12 can be increased, and the deformation of the overhanging elastic body 12 can be facilitated and the amount of deformation can be increased. As a result, it becomes possible to follow the change in the gap of the three-surface joint 70 more.
Other configurations, operations, and effects are the same as those in the first embodiment.
Here, the shape of the notch 15 may be any contour shape. In short, what is necessary is just to be the notch 15 opened to the chain case cover 60 side. Further, the notch 15 is not limited to one, and may be formed in two or more.
[0027]
Moreover, although the said embodiment demonstrated the bead 5 width of the metal bead 10 of the part in which the notch 15 was formed as the same width as another part, it is not limited to this. As shown in FIGS. 10 and 11, the width of the metal bead 10 at the position of the notch 15 may be wider than that of other portions. In the case of widening, the notch 15 can be formed larger by that amount, so that the deformation amount and deformation followability of the overhanging elastic body 12 can be further increased. Further, when the notch 15 is not enlarged, the joining portion between the overhanging elastic body 12 and the metal bead 10 is widened, and the overhanging elastic body 12 is joined to the metal bead 10, that is, the substrate 2. It becomes difficult to leave. Furthermore, when the tightening bolt is tightened, the overhanging elastic body 12 is elastically deformed by deforming the metal bead 10 as well, but by increasing the number of joints, the shape change of the overhanging elastic body 12 can be further improved. It becomes easy. In particular, the followability when the distance between the cylinder block 50 and the cylinder head 40 changes due to pulsation or the like is improved.
[0028]
Here, in all the said embodiment, although the full bead 5 was mentioned as an example and demonstrated as the metal bead 10, it is a half-shaped step bead 5 as shown in FIGS. 12-14 or FIGS. 15-17. Also good.
Moreover, although the metal bead 10 is extended to the position of the overhanging elastic body 12 in the above embodiment, the metal bead 10 is not necessarily required at the position of the overhanging elastic body 12. That is, as shown in FIGS. 18 to 20, the metal beads 10 do not have to be embedded in the overhanging elastic body 12. However, if the metal bead 10 is provided up to the position of the overhanging elastic body 12, the support of the overhanging elastic body 12 with respect to the substrate 2 can be set firmly, and peeling can be prevented more reliably. In the example shown in FIGS. 18 to 20, both sides of the overhanging elastic body 12 are fixed to the substrate 2. Moreover, when the bead 5 is comprised only from a metal bead, it is preferable to make a part of the elastic body 12 for protrusion stick to the edge part of a metal bead.
[0029]
【The invention's effect】
As described above, by adopting the present invention, it becomes possible to seal the gap formed at the three-surface joint portion of the cylinder block, the cylinder head, and the chain case cover with a simple structure.
[Brief description of the drawings]
FIG. 1 is a schematic diagram showing an arrangement of parts of an engine according to a first embodiment based on the present invention.
FIG. 2 is a partial plan view showing a substrate according to the first embodiment of the present invention.
FIG. 3 is a plan view showing an end structure of a bead according to the first embodiment of the present invention.
4 is a view of FIG. 3 as seen from a chain case cover. FIG.
5 is a view of FIG. 3 as viewed from the arrow A side.
6A and 6B are diagrams showing deformation of the overhanging elastic body according to the embodiment of the present invention, in which FIG. 6A shows an unloaded state and FIG. 6B shows a state after bolt tightening.
FIG. 7 is a plan view showing an end structure of a bead according to a second embodiment of the present invention.
FIG. 8 is a view of FIG. 7 as seen from a chain case cover.
9 is a view of FIG. 7 as viewed from the arrow A side.
FIG. 10 is a plan view showing a modification of the end structure of the bead according to the second embodiment of the present invention.
FIG. 11 is a view of FIG. 11 as seen from a chain case cover.
FIG. 12 is a plan view showing a modification of the end structure of the bead according to the second embodiment of the present invention.
FIG. 13 is a view of FIG. 11 as seen from a chain case cover.
14 is a view of FIG. 11 viewed from an arrow A. FIG.
FIG. 15 is a plan view showing a modification of the end structure of the bead according to the second embodiment of the present invention.
16 is a view of FIG. 15 as seen from a chain case cover.
17 is a view of FIG. 15 as viewed from an arrow A. FIG.
FIG. 18 is a plan view showing a modification of the end structure of a bead according to the second embodiment of the present invention.
FIG. 19 is a view of FIG. 18 as seen from a chain case cover.
20 is a sectional view taken along line XX in FIG.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Metal gasket 2 Board | substrate 3 Bead extension direction edge 5 Bead 9 Thickening part 10 Metal bead 11 (11a, 11b) Rubber bead 12 Overhang thickening part 15 Notch 40 Cylinder head 50 Cylinder block 60 Chain case cover 60a Chain case Cover joint surface 61 Chain chamber 70 Three-surface joint

Claims (5)

The cylinder block and the cylinder head are joined via a metal gasket, and a chain case cover is assembled to the side surfaces of the cylinder block and the cylinder head, and a chain chamber is formed by the side surface of the cylinder block and cylinder head and the inner surface of the chain case cover. The metal gasket used in an engine having a configuration in which is formed,
A thin metal plate is used as a substrate, and a bead extends along the chain chamber at an edge of the substrate on the chain case cover side, and an end portion of the bead extends in the cylinder block and the cylinder head. In the metal gasket extending toward the chain case cover joint surface that joins the side surface,
The chain case cover protrudes outward from at least the side surfaces of the cylinder block and the cylinder head by being compressed with respect to the end portion in the extending direction of the bead at the joint surface facing the cylinder block and the cylinder head. A metal gasket characterized in that an overhanging elastic body made of an elastic sealing material capable of coming into contact with a joint surface is provided. The bead is a metal bead formed by bending the substrate in the plate thickness direction and formed into a convex shape, and is fixed to the convex side surface of the metal bead and filled in the concave portion on the back side of the convex portion, along with the deformation of the metal bead. 2. The metal gasket according to claim 1, wherein the rubber gasket is made of an elastic sealing material that compressively deforms in the plate thickness direction, and the overhanging elastic body and the rubber bead are integrally formed. . 3. The metal gasket according to claim 2, wherein the substrate is provided with a thickened portion made of a material having rigidity higher than that of the elastic seal material, which regulates an amount of elastic deformation of the bead. The metal bead extends to the position where the overhanging elastic body is disposed and is embedded in the overhanging elastic body, and a notch opening in the embedded portion of the metal bead toward the chain case cover joint surface side The metal gasket according to claim 2 or 3, characterized by comprising: 5. The metal gasket according to claim 4, wherein the bead width at the position where the metal bead is embedded in the overhanging elastic body is set wider than that of other portions.

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