JPH09280110A - Gasket made of metal - Google Patents

Abstract

PROBLEM TO BE SOLVED: To improve reliability by reliably fixing a sealing member for sealing a step made on the surface on which a cylinder block is put into contact with a chain case to an intermediate plate in a gasket made of metal. SOLUTION: To seal a step produced on the surface at which elastic metal plates 5, 7 having beads 9, 10 formed along a chain case hole in which a chain for driving a cam shaft and a chain case are put into contact with a cylinder block, this gasket made of metal has a hole 13 for disposing a sealing member 25 in an intermediate plate 6 and cutout portions 11, 12 for cutting out the region at which the sealing member 25 is located in elastic metal plates 5, 7 and the intermediate plate 8. A metal plate 15 buried and fixed in the sealing member 25 is folded such that it can hold the mounting portion 21 of the intermediate plate 6 with a folding back portion 14.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a metal gasket made of a thin metal plate having a combustion chamber hole and a chain case hole for sealing between opposing surfaces of a cylinder block having a chain case and a cylinder head. .

[0002]

2. Description of the Related Art Conventionally, a metal gasket is one in which a cylinder block and a chain case are integrally formed in a state of being adjacent to each other, and the upper surface and the lower surface of a cylinder head are kept airtight and liquid-tight. At least one of the laminated thin metal plates that includes a main seal portion that requires a seal surface pressure and a sub seal portion that can suffice with a relatively low seal surface pressure, and that forms the main seal portion with the sub seal portion with a low seal surface pressure. It has a structure in which a sheet is extended to serve as a base material, and a soft sheet such as a beater sheet, a graphite sheet, or a compressed sheet is adhered to one or both sides of the base material. As such a metal-laminated gasket, there is one disclosed in Japanese Utility Model Laid-Open No. 63-48059.

As a metal gasket, Japanese Utility Model Application Laid-Open No.
There are known metal cylinder head gaskets disclosed in JP-A-27857 and JP-A-3-27858. The metal cylinder head gasket disclosed in Japanese Utility Model Laid-Open No. 3-27857 mentioned above is a part of a thin metal plate facing a surface having a step on the upper surface of the cylinder block or the lower surface of the cylinder head, and a through hole is provided at a position facing the step. A through hole is formed in a state of traversing the bead formed around the circumference, and a sealing material is provided inside the through hole such that a part of the sealing material projects from the through hole.

[0004]

SUMMARY OF THE INVENTION However, OHC
Type and DOHC type engines, as shown in FIG. 8, a chain case 2 for housing a camshaft driving chain.
9 is manufactured separately from the cylinder block 28, and a chain case 29 having a chain case space 33 is adjacent to a cylinder block 28 having a cylinder, that is, a combustion chamber 35, and is fastened with a bolt. It is common. A metal gasket is arranged between the cylinder head and the chain case 29 and the cylinder block 28. In the figure, 32 indicates a bolt hole. Moreover, for the purpose of reducing the weight of the engine, the chain case 2
The mounting side surface of 9 is open so as to reduce the weight of the chain case 29, and the space portion 33 for running the chain is structured by the inner wall of the space portion 33 of the chain case 29 and the side surface of the cylinder block 28. There is. Due to such a fixed structure of separate parts, even if the upper surface 34 of the cylinder block 28 and the upper surface 31 of the chain case 29 are finished flat, the joint or contact surface 36 between the cylinder block 28 and the chain case 29. In the above, it is unavoidable that a step 30 is formed between both upper surfaces, but it is not possible to avoid the step 3 due to long-term use of the engine.
It is unavoidable that 0 expands. In this way, when the step 30 is formed between the upper surfaces, oil such as lubricating oil is splashed and splashes on the step portion as the chain travels in the chain case 29 for driving the camshaft, and the step portion is formed. Then, there arises a problem that oil leaks from the portion to the outside of the chain case or enters between the facing surfaces of the cylinder block 28 and the cylinder head.

Further, the metal gasket as described above is
A thin metal plate laminated on the cylinder block 28 side is used as a base material and a soft sheet is adhered to one side of the base material, and airtightness and liquid tightness due to the step 30 cannot be maintained. If a thin metal plate is used as a base material and soft sheets are adhered to both sides,
Is extremely small, airtightness and liquidtightness can be maintained, but when the step 30 becomes large, the thickness of the soft sheet itself is required to secure the sealing performance, and the thickness of the main seal part is It becomes necessary to design the stacking of the metal plates in consideration of the sheet thickness. Generally, since the beater sheet, graphite sheet, compressed sheet, and the like constituting the soft sheet have a thickness of at least about 0.5 mm from the beginning, the thickness of the main seal portion needs to be adjusted to the thickness. Therefore, in order to secure a high surface pressure in the main seal portion, it is necessary to increase the number of laminated thin metal plates.

In the metal cylinder head gasket, a through hole is formed along the periphery of the through hole, and a sealing material is provided inside the through hole so that a part of the sealing material projects from the through hole. The sealing property of the portion facing the step around the through hole is retained by the sealing material provided inside the through hole. Moreover, the sealing material extends all around the through hole and is not fitted in the intermediate plate.

Generally, there are two steps formed on the contact surface between the cylinder block and the chain case. In other words, there is a step that occurs when the upper surface of the chain case is lower than the upper surface of the cylinder block, and a step that occurs when the upper surface of the chain case is higher than the upper surface of the cylinder block. When the upper surface of the chain case is lower than the upper surface of the cylinder block, the surface pressure of the chain case is lower than that of the cylinder block. Therefore, the surface pressure of the step portion and the chain case must be considered. When the upper surface of the chain case is higher than the upper surface of the cylinder block, the surface pressure concentrates on the chain case, and the surface pressure on the cylinder block side decreases. The surface pressure around the combustion chamber hole of the cylinder block requires a high surface pressure, but when a metal gasket is used, it becomes difficult to adjust the surface pressure.

Therefore, in the above-mentioned metal gasket, the lower surface of the cylinder head is generally a flat continuous lower surface, but even if there is a step between the upper surface of the cylinder block and the upper surface of the chain case, the gasket is manufactured. There is a problem to be solved in that the oil in the chain case is prevented from entering the stepped portion without taking the measure of increasing the number of laminated thin metal plates, which significantly increases the cost. Therefore, a metal gasket as described above, in which a seal member is arranged in a step region, has been developed, and the present applicant previously filed as Japanese Patent Application No. 6-236050.

However, in the metal gasket, even if the seal member is arranged in the step region, how to secure the seal member at a predetermined place without dropping the seal member at a predetermined place. There is a problem of mounting.

[0010]

SUMMARY OF THE INVENTION An object of the present invention is to solve the above-mentioned problems and to seal between the opposing surfaces of the cylinder block and the cylinder head, and to contact the cylinder block and the chain case. Even if there is a step on the contact surface, in order to securely arrange the seal member in the area of the step, by fixing the seal member to the intermediate plate, the seal member can be stably arranged at a predetermined place without falling off. , The sealing member prevents oil and the like from leaking from the step to improve the sealing property in the vicinity of the contact surface, and the surface pressure between the cylinder head and the cylinder block can be easily adjusted, and the manufacturing cost is low. To provide a highly reliable metal gasket.

According to the present invention, the metal constituting the main seal portion having the combustion chamber hole and the sub seal portion having the chain case hole is provided to seal between the opposing surfaces of the cylinder block to which the chain case is attached and the cylinder head. In a metal gasket made of a thin plate, the thin metal plate is composed of an elastic metal plate and an intermediate plate arranged in contact with the elastic metal plate, and a half bead is formed on the elastic metal plate along a chain case hole. A seal member is disposed on the elastic metal plate and the intermediate plate in a region of the sub seal portion adjacent to the main seal portion to seal a step generated at a boundary portion between the cylinder block and the chain case. Each notch is formed, and a metal plate for fixing the seal member to the intermediate plate is attached to the seal member. It relates to a metal gasket, characterized in that.

In this metal gasket, the elastic metal plate is arranged at least on the cylinder head side and is composed of one or two sheets. Also, the intermediate plate is composed of one or two sheets. It is necessary that the number of the elastic metal plates and the number of the intermediate plates are appropriately selected according to the required thicknesses of the main seal portion and the sub seal portion. For example, when the main seal portion and the sub seal portion are composed of the two elastic metal plates and the two intermediate plates, the tightening force of the tightening bolts in the main seal portion and the sub seal portion is adjusted. By doing so, good sealing properties can be achieved. Further, when the chain case side projects more than the cylinder block side, for example, the main seal portion is composed of the two elastic metal plates and the two intermediate plates, and the sub seal portion is one. Good sealability can be achieved by configuring the auxiliary seal portion to be one less than the main seal portion, as in the case of the elastic metal plate and the two intermediate plates.

Further, the chain case hole side is cut off from the cutout portion formed in the elastic metal plate.

Further, the cutout portion formed in the intermediate plate is formed in a hole into which the seal member is fitted, and the intermediate plate has a mounting portion formed on the chain case hole side of the hole. is there. Further, the metal plate embedded in the seal member is bent at a portion extending from the seal member to the side of the chain case hole and is fixed to the intermediate plate while holding the attachment portion of the intermediate plate. ing. Moreover, the plate thickness of the portion of the intermediate plate that is bent and holds the mounting portion of the intermediate plate is set to be smaller than the total plate thickness of the first and second elastic metal plates and the intermediate plate. There is something.

Further, in this metal gasket, the surface of the metal thin plate is coated with heat-resistant resin or rubber, so that the metal-metal contact between the metal thin plates, the upper surface of the cylinder block and the cylinder head. It is possible to avoid the metal-to-metal contact of the metal thin plate with the lower surface of the metal thin plate and improve the durability of the metal gasket.

Since this metal gasket is constructed as described above, the seal member can be stably and reliably arranged in the area of the abutting surface without falling off, and the area of the abutting surface is good. Can be sealed. Moreover,
There is almost no effect on the combustion chamber hole by the seal member located in the area of the contact surface between the chain case and the cylinder block, and the high temperature and high pressure combustion gas generated in the combustion chamber hole is exposed to the outside from between the opposed surfaces. It also prevents the leakage of liquid flowing between the facing surfaces of the liquid such as water holes and oil holes, and ensures a high sealing surface pressure against the metal gasket between the facing surfaces. Can be sealed.

Further, in this metal gasket, the wall surface of the chain case hole of the chain case is constituted by the side surface of the cylinder block and the inner wall surface of the chain case, and the contact surface between the cylinder block and the chain case is formed. Since the step area is well sealed, the oil in the chain case is prevented from splashing from the chain as the chain runs and entering the step on the contact surface, preventing the oil from splashing to the outside. To be done. In addition, even when a step at the contact surface between the cylinder block and the cylinder head is large and the sealing surface pressure is low, the thickness of the sealing member is adjusted to secure good sealing performance in the step region. Can be.

[0018]

BEST MODE FOR CARRYING OUT THE INVENTION An embodiment of a metal gasket according to the present invention will be described below with reference to FIGS.
1 is a partial plan view showing an embodiment of a metal gasket according to the present invention, FIG. 2 is an enlarged plan view of a portion A in FIG.
3 is a sectional view taken along line BB in FIG. 1, FIG. 4 is a sectional view taken along line C-C in FIG. 1, FIG. 5 is a sectional view taken along line D-D in FIG. 1, and FIG. 6 is line E in FIG. -E is a cross-sectional view and FIG. 7 is a cross-sectional view illustrating each structure of the metal thin plate in the metal gasket of FIG.

As shown in FIG. 8, this metal gasket seals between the opposed surfaces of the cylinder block 28 and the chain case 29 and the cylinder head (not shown). The chain case 29 is the cylinder block 2
It is formed as a separate component from 8, and is attached to the side surface of the cylinder block 28. The chain case 29 is
In order to reduce the weight, the mounting side surface of the cylinder block 28 is formed to be open. The chain case 29 has a U-shape when viewed in a horizontal section, and forms a mating surface, that is, a contact surface 36 with the cylinder block 28 at two places. The inner wall surface of the chain case 29 and the side surface of the cylinder block 28 form a space 33 through which a chain for driving a camshaft runs.

In this metal gasket, the elastic metal plates 5 and 7 and the intermediate plates 6 and 8 made of thin metal plates have the combustion chamber holes 3 corresponding to the combustion chambers 35 of the cylinder block 28, and the chain case 29 of the chain case 29. Chain case holes 4 and the like are formed corresponding to the spaces 33. Elastic metal plates 5, 7
In order to configure the main seal portion 1 at a distance slightly away from the inner end edge of the combustion chamber hole 3, the combustion chamber hole 3
A bead 37 having a mountain-shaped cross-section concentrically and annularly is formed so as to project toward the intermediate plates 6 and 8 so as to come into contact with the intermediate plates 6 and 8. In this embodiment, the sub-seal portion 2 is made up of the elastic metal plates 5, 7 forming the main seal portion 1.
The metal thin plates of the intermediate plates 6 and 8 are extended to the periphery of the opening upper surface of the chain case hole 4 of the chain case. Further, the thin metal plate is composed of the same number of main seal portions 1 and sub seal portions 2, but the tightening force of the bolts should be adjusted between the main seal portion 1 side and the sub seal portion 2 side. Thus, the sealability between the main seal portion 1 on the combustion chamber side and the sub seal portion 2 on the chain case side can be appropriately adjusted.

This metal gasket is, as described above,
It comprises a main seal portion 1 and a sub seal portion 2 having a metal thin plate integrally extending a part of the metal thin plate constituting the main seal portion 1. The main seal portion 1 is a cylinder block 28 shown in FIG.
Is a seal portion interposed between the upper surface 34 of the engine and the lower surface of the cylinder head.
Combustion chamber hole 3, oil hole 3 formed corresponding to
9, the periphery of various holes such as the knock hole 22 and the water hole 23 is sealed. One of the opposing surfaces to be sealed of the sub-seal portion 2 is the upper surface 31 forming the space 33 of the chain case 29 shown in FIG. 8 and the upper surface 34 adjacent to the side surface of the cylinder block 28 to which the chain case 29 is attached. The other of the facing surfaces seals a region corresponding to one of the facing surfaces of the main seal portion 1 and the lower surface of the cylinder head which is continuous and flat. In this embodiment, the main seal portion 1 and the sub seal portion 2 are integrally and continuously formed. Further, the elastic metal plates 5 and 7 are provided with beads 9 and 10 along the chain case hole 4 of the chain case in the same manner as the main seal part 1 in order to form the sub seal part 2.

This metal gasket seals between the opposed surfaces of the cylinder block to which the chain case is attached and the cylinder head, and is provided with the combustion chamber hole 3 which constitutes the main seal portion 1 and the sub seal portion 2. It has a configuration in which a plurality of (four in FIG. 3 to FIG. 7) metal thin plates are laminated. A plurality of thin metal plates are elastic metal plates 5 arranged on both sides.
And an elastic metal plate 7, and intermediate plates 6 and 8 arranged between the elastic metal plates 5 and 7. Elastic metal plate 5
Is a bead plate located on the cylinder head side, the elastic metal plate 7 is a stopper plate located on the cylinder block 28 side, and the intermediate plates 6 and 8 are adjustments having the function of adjusting the tightening thickness. The board is made up. In this embodiment, the two intermediate plates 6 and 8 are used, but it is also possible to construct the structure in which one intermediate plate 6 is used. When the metal gasket is sandwiched between the opposing surfaces of the cylinder head and the cylinder block 28 and tightened, the elastic metal plate 5
And bead 37 provided around the combustion chamber hole 3
1 (only one is shown in FIG. 1) contacts the facing surface of the cylinder head around the combustion chamber hole 3 to form an annular seal portion.

In this metal gasket, the elastic metal plate 5 has the chain case hole 4 formed corresponding to the space 33 (FIG. 8) formed in the chain case 29 in which the camshaft driving chain runs. Half beads 9 are formed along the circumference. Similarly, on the elastic metal plate 7, half beads 10 are formed along the circumference of the chain case hole 4 formed corresponding to the space portion 33.
Since the intermediate plate 6 seals the step 30 (FIG. 8) generated at the boundary portion between the chain case 29 and the cylinder block 28, that is, the contact surface 36, the intermediate plate 6 is provided in the region of the sub seal portion 2 close to the main seal portion 1. , A rectangular hole 13 forming a notch portion into which the seal member 25 is fitted is formed, and the hole 13 is the contact surface 3
6 (FIG. 8) extends in the direction perpendicular to the chain case 29 side. The elastic metal plates 5, 7 and the intermediate plate 8 include the intermediate plate 6
Rectangular notches 11 and 12 are formed by cutting out the chain case hole 4 side in the region where the seal member 25 is located so as not to interfere with the seal member 25 that is fitted in. As shown in FIGS. 5 and 6, beads 16 and 17 are formed around the elastic metal plates 5 and 7 in the main seal portion 1. Also, as shown in FIG. 6, the oil hole 3
Beads 18 and 19 are formed around 9.

This metal gasket is particularly characterized by a structure for fixing the seal member 25 to the intermediate plate 6, and since the seal member 25 is attached to the intermediate plate 6, the seal member 25 is attached.
One end of the metal plate 15 is embedded in the fitting hole 20 formed in the middle part of the. The metal plate 15 embedded in the seal member 25 is bent at the portion extending from the seal member 25 toward the chain case hole 4 side, and is attached to the attachment portion 2 of the intermediate plate 6.
1 is held by the folded portion 14 and fixed to the intermediate plate 6. Therefore, the seal member 25 is attached to the mounting portion 21 of the intermediate plate 6.
Is firmly fixed to the intermediate plate 6 without falling off from the rectangular hole 13 of the intermediate plate 6, and is stably fixed to the intermediate plate 6. In this embodiment, the seal member 25 is made of a non-metallic material such as a heat-resistant resin or silicone rubber, and is formed as a rod-shaped member having a square cross section so as to fit into the rectangular hole 13 of the intermediate plate 6. Of course, the shape of the seal member 25 may be circular in cross section, and the shape is not limited to the embodiment.

This metal gasket is required to satisfy the following conditions regarding its plate thickness. First, metal plate 1
The elastic metal plate 5 and the elastic metal plate 7 are twice as thick as the plate thickness of 5.
It is necessary that the total thickness of the intermediate plate 8 and the intermediate plate 8 is not larger than one. If this plate thickness condition is satisfied, the elastic metal plate may be one, and in that case, the elastic metal plate 5 on the cylinder head side is used. In other words, the plate thickness T ₂ of the portion where the metal plate 15 is bent and the mounting portion 21 of the intermediate plate 6 is held is
Total thickness T of the elastic metal plates 5, 7 and the intermediate plates 6, 8
It is set to a size smaller than ₁ . Regarding the thickness of the seal member 25, the thickness T ₃ of the seal member 25 is
It is necessary that the elastic metal plates 5, 7 and the intermediate plates 6, 8 have a size larger than the total thickness T ₂ of the four plates. Further, a hole formed in the intermediate plate 6 as a deformation allowance of the seal member 25 so that the seal member 25 can be favorably deformed by the pressing force when the metal gasket is tightened between the chain case and the cylinder head. It is necessary that a gap S (FIG. 3) be formed between the peripheral wall surface of 13 and the outer peripheral surface of the seal member 25. In addition, the seal member 25
Has a length L set to be approximately half the length of the chain case hole 4 of the chain case 29, for example. By setting the size of the sealing member 25 as described above, it is possible to sufficiently absorb the step 30 generated on the contact surface 36 and improve the sealing performance.

Further, when laminating thin metal plates, the elastic metal plates 5 and 7 located on the cylinder head side have good workability so as to easily follow the cylinder head which is more easily deformed than the cylinder block 28. Material is used.
For example, the elastic metal plates 5 and 7 are made of SUS301 and have a hardness Hv.
Made of 300-500 material, thickness 0.2-03m
m. In some cases, the elastic metal plate 7 is made of SUS3
04 or SUS430 and is made of a material having a hardness Hv of 150 to 200. The intermediate plate 6 is made of SUS430 or SPC with a material having a hardness Hv of 150 to 200, and has a thickness of 0.5 to 0.6 mm. The intermediate plate 8 is a SU
It is made of a material of S304 or SUS430 and has a thickness of 0.1 to 0.15 mm. Further, the metal plate 15 for attaching the seal member 25 to the intermediate plate 6 is made of SUS43.
0 or SPC material with a thickness of 0.15 to 0.
2 mm.

Further, as shown in FIG. 7, in this metal gasket, a thin metal plate is heat-treated, and, for example, an elastic metal plate 5 is coated with fluororubber 26 and acrylic silicone 27 on the front and back surfaces thereof. The plate 8 is coated with a fluororubber 26 and an acrylic silicone 27, and the elastic metal plate 7 is coated with a non-metallic material such as the fluororubber 26 and an acrylic silicone 27, so that the metal between the thin metal plates and the cylinder head and the cylinder block is coated with a metal. It is possible to avoid a contact state with a metal and ensure corrosion resistance, durability and strength as a metal gasket. Further, even if the metal gasket has irregularities on the machined surface, the non-metallic material can cover the irregularities and perform a sufficient sealing function.

[0028]

The metal gasket according to the present invention is configured as described above, and in particular, the metal plate fixed to the seal member is bent to hold the attachment portion of the intermediate plate and to hold the seal member. Since it is fixed to the intermediate plate, the seal member is stably positioned in the vicinity of the stepped portion without falling off, and even if there is a step on the contact surface between the chain case and the cylinder block, Even if the seal member comes into direct contact with the step and the step becomes relatively large, the bead and the seal member sufficiently absorb the step and oil leaks from the inside of the chain case to the outside. There is no problem, and a reliable seal can be achieved, and the sealability can be improved and the reliability can be improved. Moreover,
When attaching the seal member to the intermediate plate, the metal plate can be firmly fixed simply by bending it, and the attachment and detachment are extremely easy.

[Brief description of drawings]

FIG. 1 is a partial plan view showing an embodiment of a metal gasket according to the present invention.

FIG. 2 is an enlarged plan view of a portion A in FIG.

FIG. 3 is a sectional view taken along line BB in FIG. 1;

4 is a cross-sectional view taken along the line CC of FIG.

5 is a cross-sectional view taken along the line DD of FIG.

6 is a cross-sectional view taken along the line EE in FIG.

FIG. 7 is a cross-sectional view illustrating each metal thin plate in the metal gasket of FIG.

FIG. 8 is a perspective view showing a cylinder block with a chain case.

[Explanation of symbols]

 1 Main seal part 2 Sub seal part 3 Combustion chamber hole 4 Chain case hole 5,7 Elastic metal plate 6,8 Intermediate plate 9,10 Half bead 11,12 Notch part 13 Hole (notch part) 14 Folding part 15 Metal plate 16, 17, 18, 19 Half bead 20 Fitting hole 21 Mounting part 25 Sealing member 26 Fluoro rubber (rubber) 27 Acrylic silicone (resin) 28 Cylinder block 29 Chain case 30 Step

Claims (8)

[Claims] 1. A thin metal plate that constitutes a main seal portion having a combustion chamber hole and a sub seal portion having a chain case hole for sealing between opposing surfaces of a cylinder block having a chain case and a cylinder head. In the metal gasket consisting of, the metal thin plate is composed of an elastic metal plate and an intermediate plate arranged in contact with the elastic metal plate, and a half bead is formed in the elastic metal plate along a chain case hole, The elastic metal plate and the intermediate plate are provided with a notch for arranging a seal member in an area of the sub seal portion near the main seal portion in order to seal a step generated at a boundary portion between the cylinder block and the chain case. And a metal plate for fixing the seal member to the intermediate plate is attached to the seal member. And a metal gasket. 2. The metal gasket according to claim 1, wherein the elastic metal plate is arranged at least on the cylinder head side and is composed of one or two sheets. 3. The metal gasket according to claim 1, wherein the intermediate plate is composed of one or two sheets. 4. The metal gasket according to claim 1, wherein the cutout portion formed in the elastic metal plate is cut off on the side of the chain case hole. 5. The cutout portion formed in the intermediate plate is formed in a hole into which the seal member is fitted, and the intermediate plate is formed with a mounting portion on the chain case hole side of the hole. The metal gasket according to any one of claims 1 to 4. 6. The intermediate plate, wherein the metal plate embedded in the seal member is bent at a portion extending from the seal member toward the chain case hole to embrace the attachment portion of the intermediate plate. The metal gasket according to claim 5, which is fixed to the metal gasket. 7. The plate thickness of a portion of the intermediate plate that is bent and holds the mounting portion of the intermediate plate is smaller than the total plate thickness of the elastic metal plate and the intermediate plate. Item 7. The metal gasket according to item 6. 8. The heat-resistant resin or rubber is coated on the surface of the thin metal plate.
7. The metal gasket according to any one of 7.