JP3310313B2 - Cylinder head gasket - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a cylinder head gasket interposed between a cylinder head and a cylinder block of an internal combustion engine, and more particularly, to forming a combustion chamber hole in a metal substrate and forming a bead around the hole. In addition, the present invention relates to a cylinder head gasket provided with a seal member along a peripheral edge of a bead.

[0002]

2. Description of the Related Art With regard to a cylinder head gasket interposed between a cylinder head and a cylinder block of an internal combustion engine, a cylinder head gasket made of a metal plate has recently attracted attention. For example, a plurality of combustion chamber holes through which a combustion gas passes are formed in a metal substrate, and beads are formed around each combustion chamber hole so that a high surface pressure can be secured to the joining member. It has been known.

[0003] With regard to such a cylinder head gasket, for example, Japanese Utility Model Laid-Open Publication No. 64-8556 discloses a method in which a soft sealing member is provided at the base of a bead on the water hole side to prevent corrosion due to water penetration. A disclosed cylinder head gasket is disclosed. In addition, the actual opening Hei 1-141354
Japanese Patent Application Laid-Open Publication No. H11-139,086 also discloses a metal gasket for a cylinder head in which a heat-resistant elastic member layer is formed all around or partly along the periphery of a bead. Furthermore, it is actual fair 2-35086
In the publication, the top of the bead portion of the metal gasket substrate,
Change the thickness and width of the sealing material applied according to the magnitude of the contact surface pressure of the mating surface acting on the base, and maintain the desired sealing pressure of the bead part by applying the sealing material by screen printing. It has been proposed to save expensive sealing material.

[0004]

Problems to be Solved by the Invention
In the cylinder head gasket described in JP-B-56, a sealing member is provided at the base of the bead, that is, at the skirt edge, so that the sealing performance with respect to combustion gas is improved. However, with the recent increase in output and miniaturization of internal combustion engines,
The distance between the mutually adjacent combustion chamber holes formed in the substrate, that is, the width of the intermediate portion, has become shorter, and it has become an important issue to ensure the sealing performance between the two. For this reason, for example, a bead that surrounds each of the adjacent combustion chamber holes is gathered at an intermediate portion to form a bead having substantially the same width so as to ensure a predetermined surface pressure. As for the member, it is desired that a substantially uniform surface pressure is secured over the entire circumference of each combustion chamber hole including the intermediate portion between the adjacent combustion chamber holes.

Further, in a cylinder head gasket in which a plurality of bolt holes are formed around the combustion chamber hole, bolts are inserted through these bolt holes and tightened between the cylinder head and the cylinder block. A large axial force is applied to the vicinity of the bolt hole as compared with other portions, and the surface pressure increases. The aforementioned Japanese Utility Model Publication No. 2-35086 describes that the desired sealing pressure of the bead portion is maintained by changing the thickness of the sealing material adhered to the bead portion. However, it is not intended to make the surface pressure distribution of the seal member itself provided uniform, nor to take measures in view of the surface pressure distribution peculiar to the seal member of the cylinder head gasket as described above.

Further, it is needless to say that it is desirable for the cylinder head gasket to have a surface pressure distribution according to the distribution of the fastening force between the cylinder head and the cylinder block of the internal combustion engine to which it is mounted. Regarding the distribution of the above-mentioned fastening force, in the longitudinal direction of the cylinder head, there is substantially the same fastening force distribution around each combustion chamber hole except for the front and rear portions, but in the width direction, there is a different fastening force distribution between the intake side and the exhaust side. There is. In such a case, the seal member is not formed so as to have a symmetrical surface pressure distribution in both front and rear and left and right with respect to the cylinder head gasket. If the difference is made between the exhaust side and the exhaust side, the sealing performance will be further improved.

Accordingly, the present invention provides a plurality of combustion chamber holes through which a combustion gas passes through a metal substrate, forms beads around each combustion chamber hole, and forms an outer peripheral skirt on the convex side of each bead. In a cylinder head gasket provided with a seal member along an edge, it is an object to secure a substantially uniform surface pressure over the entire periphery of each combustion chamber hole with respect to the seal member, and to further improve the sealability.

[0008]

SUMMARY OF THE INVENTION To achieve the above object, the present invention provides a metal substrate having a plurality of combustion chamber holes through which a combustion gas passes, and a plurality of combustion chamber holes. A plurality of bolt holes are formed around the periphery of each of the plurality of combustion chamber holes , on both left and right sides in the longitudinal direction of the substrate.
The position and the plurality of combustion chamber holes are opposed to each other at an intermediate portion adjacent to each other.
In a cylinder head gasket provided with a bead at a position facing each other and a sealing member continuous along the outer peripheral skirt edge of each of the beads on the one side in the left-right direction with respect to the longitudinal direction of the substrate. The thickness of the seal member is different between a portion where the plurality of bolt holes are located between adjacent bolt holes and is farthest from the bolt holes and another portion.

The thickness of the seal member on one side in the left-right direction with respect to the longitudinal direction of the substrate of the cylinder head gasket is determined from a bolt hole at a central portion between the bolt holes.
The thickness of the farthest portion was set to the maximum value, the most distant part from the bolt holes at the central portion between the thickness of the portion where the plurality of combustion chamber holes are facing the intermediate portion adjacent to each other the bolt holes
Is set smaller than the partial thickness, closest to the bolt holes
It is good to set the thickness of the part where it fell to the minimum value.

Further, regarding the thickness of the sealing member on the other side in the left-right direction with respect to the longitudinal direction of the substrate of the cylinder head gasket, the thickness of a portion where the plurality of combustion chamber holes face an intermediate portion adjacent to each other. it may be set to the maximum value of.

[0011]

When the cylinder head gasket having the above structure is interposed between the cylinder head and the cylinder block, and the two are fastened with a predetermined tightening force, the beads are compressed and deformed. A predetermined surface pressure against the cylinder head and the cylinder block is ensured by the elastic restoring force of the compression-deformed bead, and the seal member is in close contact with one of the beads, thereby sealing between the two. In this case, with respect to the thickness of the sealing member on one side in the left-right direction with respect to the longitudinal direction of the substrate, a plurality of bolt holes are located between the bolt holes adjacent to each other, and a portion farthest from the bolt hole and other portions , A substantially uniform surface pressure is obtained over the entire circumference of the seal member.

[0012] Further, regarding the thickness of the sealing member on one side in the left-right direction with respect to the longitudinal direction of the substrate of the cylinder head gasket, the most distant from the bolt hole at the central portion between the bolt holes.
The thickness of the portion is set to a maximum value, a plurality of combustion chamber holes is smaller than the thickness of the farthest portion from the bolt hole in the central portion between the thick bolt hole portions facing the intermediate portion adjacent to each other The thickness of the portion closest to the bolt hole is set to the minimum value, and the plurality of combustion chamber holes are adjacent to each other with respect to the thickness of the sealing member on the other side in the left-right direction with respect to the longitudinal direction of the substrate. According to the cylinder head gasket in which the thickness of the portion facing the intermediate portion is set to the maximum value, even if the distribution of the fastening force applied to the cylinder head gasket differs in the left-right direction with respect to the longitudinal direction of the substrate, each combustion chamber hole A substantially uniform surface pressure distribution can be obtained over the entire circumference of the sealing member, and a better sealing property can be obtained.

[0013]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of a cylinder head gasket according to the present invention will be described below with reference to the drawings. FIG. 1 shows a cylinder head gasket interposed between a cylinder head and a cylinder block of a multi-cylinder internal combustion engine according to one embodiment of the present invention, and a substrate made of an elastic metal plate, for example, a stainless steel plate (SUS). The substrate 10 is provided with a number corresponding to the number of cylinders, for example, as shown in FIG. 1, four combustion chamber holes 11 are formed in a straight line for an in-line four-cylinder internal combustion engine. The substrate 10 has a plurality of cooling water holes (not shown).
In addition, a lubricating oil hole (not shown) is formed, and a plurality of bolt holes 12 are formed around the combustion chamber hole 11.

Further, a bead 13 is formed around each combustion chamber hole 11, as is apparent from FIG. Bead 13
Are formed to have the same width over the entire circumference of each combustion chamber hole 11, but merge at a portion located between the adjacent combustion chamber holes 11 to form one bead. Bolt hole 12
For example, a total of ten pieces are formed at substantially equal intervals around each combustion chamber hole 11, and are arranged such that the upper side in FIG. 1 is the intake side of the internal combustion engine at the time of assembling. Is inserted and tightened between a cylinder head (not shown) and a cylinder block (not shown).

The bead 1 on the convex side of the bead 13 of the substrate 10
On a flat surface from 3 to the combustion chamber hole 11, a perfectly circular metal ring having a predetermined width, for example, a stainless steel spacer, a so-called shim ring 14, is joined. That is, shim ring 1
4 is set to a predetermined width sufficient to secure the sealing function by itself, and as shown in FIG.
Is welded to the substrate 10 substantially continuously over the entire circumference by, for example, a pulse-driven laser welding machine. As a result, a continuous welded portion 15 is formed on the entire periphery of the shim ring 14 as shown in FIG.

A seal member 16 made of, for example, a vulcanized fluorine rubber is formed along the outer peripheral skirt on the convex side of the bead 13. FIG. 3 shows the vicinity of the gathering portion 13c where the adjacent beads 13 and 13 gather together as viewed from the upper side of FIG. 1, that is, from the intake side. The thickness Ta is set to the maximum value, and the thickness Tb of the portion B where the combustion chamber holes 11 and 11 face the intermediate portion adjacent to each other is set to be smaller than the maximum thickness Ta. Then, the thickness Td of the portion D near the bolt hole 12 is set to the minimum value, and accordingly, the thickness Td of the remaining portion C is set.
c is set to an intermediate value between the thicknesses Tb and Td. The maximum thickness Ta of the seal member 16 may be set to be equal to or slightly larger than the thickness of the shim ring 14. It is preferable that the shape of each of the portions A to D is formed in a smooth mountain shape as shown in FIG. 3, but it may be formed in a step shape with a step.

Thus, each part A to D of the seal member 16
The thicknesses Ta to Td of Ta>Tb> as shown in FIG.
These values are formed so as to satisfy Tc> Td, and these values are appropriately set so as to obtain a uniform surface pressure over the entire circumference of the combustion chamber hole 11. On the other hand, the seal member 16 on the lower side, that is, the exhaust side in FIG. 1 is set so that the thickness of the portion B where the combustion chamber holes 11 and 11 face the intermediate portion adjacent to each other becomes the maximum value, and the other portions E Is a substantially constant thickness T which is thinner than this.
e, for example, it is set to the same thickness as Tb or Tc.

Although not shown, the substrate 10 and the shim ring 14 are formed before forming the seal member 16 of this embodiment.
It is preferable to form a vulcanized rubber layer made of vulcanized fluoro rubber on the entire surface of the substrate. Furthermore, in order to ensure the sealing performance when joining with the cylinder block and cylinder head,
A non-vulcanized rubber containing no vulcanizing agent or an unvulcanized rubber containing a vulcanizing agent but not vulcanized is applied to all surfaces of the seal member 16, the shim ring 14, and the substrate 10. It may be attached.

When the cylinder head gasket constructed as described above is mounted on the internal combustion engine and a tightening force is applied,
First, the top of the bead 13 contacts the cylinder head (or cylinder block), and the bead 13 is compressed and deformed. At this time, since the height of the bead 13 is greater than the thickness of the shim ring 14, the bead 13 can be deformed until it becomes equal to the thickness of the shim ring 14, but no more. That is, when the gap between the cylinder head and the cylinder block is tightened and the shim ring 14 is compressed, the deformation of the bead 13 does not proceed any further, and the cylinder head gasket is moved by the elastic restoring force to the cylinder block and the cylinder head. Will be in close contact. Therefore, from the viewpoint of the sealing function for the combustion chamber hole 11, the shim ring 14
Keeps the sealing function of the bead 13 and also functions as a sealing member itself, and eventually constitutes a three-stage seal including the sealing member 16 to ensure stable sealing performance.

The seal member 16 is formed to have an appropriate thickness distribution on the intake side and the exhaust side in accordance with the distribution of the fastening force applied to the cylinder head gasket. In the portion where the combustion chamber 16 is formed, a substantially uniform surface pressure distribution is obtained over the entire circumference of each combustion chamber hole 11, and a good sealing property is secured. The thickness of the portion B of the seal member 16 where the combustion chamber holes 11, 11 face the intermediate portion adjacent to each other may be different between the intake side and the exhaust side. The thickness of the same portion B on the upper side of the exhaust gas may be larger than the thickness of the same portion B on the exhaust side.

[0021]

Since the present invention is configured as described above, the following effects can be obtained. That is, in the cylinder head gasket of the present invention, with respect to the thickness of the sealing member on one side in the left-right direction with respect to the longitudinal direction of the substrate, a plurality of bolt holes are located between adjacent bolt holes.
Since the value is different between the portion farthest from the seal member and the other portions, substantially uniform surface pressure is obtained over the entire circumference of the seal member, and good sealing performance is secured over the entire circumference of the combustion chamber hole. be able to.

Further, in the case where the seal member of the cylinder head gasket is formed so that the distribution of the thickness differs in the left-right direction with respect to the longitudinal direction of the substrate, the distribution of the fastening force applied to the cylinder head gasket is reduced. Even in the case where it differs in the left-right direction with respect to the longitudinal direction, a substantially uniform surface pressure distribution can be obtained over the entire circumference, so that better sealing properties can be ensured.

[Brief description of the drawings]

FIG. 1 is a plan view of a cylinder head gasket according to one embodiment of the present invention.

FIG. 2 is a cross-sectional view of a part of the cylinder head gasket according to one embodiment of the present invention, which is a cross-sectional view taken along line XX of FIG.

FIG. 3 is a side view of a part of the cylinder head gasket according to one embodiment of the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 10 Substrate 11 Combustion chamber hole 12 Bolt hole 13 Bead 14 Shim ring 16 Seal member

Continuing on the front page (72) Inventor Zenichi Shinbo 1 Toyota Town, Toyota City, Aichi Prefecture Toyota Motor Corporation (72) Inventor Kazuya Nakata 1 Toyota Town Toyota City, Aichi Prefecture Toyota Motor Corporation (56) References JP-A-3-156154 (JP, A) JP-A-62-261756 (JP, A) JP-A-62-155375 (JP, A) Fully open Showa 64-8556 (JP, U) Really open Showa 62 -1777963 (JP, U) (58) Field surveyed (Int. Cl. ⁷ , DB name) F16J 15/12

Claims (3)

(57) [Claims] 1. A plurality of combustion chamber holes through which a combustion gas passes through a metal substrate, and a plurality of combustion chamber holes are formed in a line, and positions of the left and right sides of the plurality of combustion chamber holes on both sides in the longitudinal direction of the substrate.
The plurality of combustion chamber holes face intermediate portions adjacent to each other.
A plurality of bolt holes were drilled at the positions , a bead was formed around each of the plurality of combustion chamber holes, and a sealing member was provided along the outer peripheral hem on the convex side of each of the beads. In the cylinder head gasket, the thickness of the sealing member on one side in the left-right direction with respect to the longitudinal direction of the substrate is defined as a portion where the plurality of bolt holes are located between bolt holes adjacent to each other and are farthest from the bolt holes. A cylinder head gasket characterized by different values for other parts. 2. The method according to claim 1, wherein the thickness of the sealing member on one side in the left-right direction with respect to the longitudinal direction of the substrate of the cylinder head gasket is determined by a bolt hole at a central portion between the bolt holes.
Et set farthest the thickness of the portion to the maximum value, the bolt holes in the central portion between the plurality of thickness <br/> the bolt hole portion combustion chamber holes facing the intermediate portion adjacent to each other Farthest from
Set smaller than the thickness of the part, and closest to the bolt hole
The cylinder head gasket according to claim 1 , wherein the thickness of the portion is set to a minimum value. 3. With respect to the thickness of the sealing member of the other side in the lateral direction to the longitudinal direction of the substrate of the cylinder head gasket, the thickness of the portion where the plurality of combustion chamber holes are facing the intermediate portion adjacent to each other cylinder head gasket according to claim 2, wherein the set to the maximum value of.