JP2018123705A - gasket - Google Patents

Abstract

SOLUTION: A gasket 2 comprises a first seal portion S1 for an exhaust manifold 3 and a second seal portion S2 for an EGR device 4, and both seal portions S1, S2 are integrally constituted. A boundary part S3 of both seal portions S1, S2 is provided with a slit 2G long in a direction crossing a longitudinal direction of the gasket 2, and parts adjacent to both ends are crack tolerance portions 2H, 2H.EFFECT: The number of components can be reduced in comparison with a conventional one in which a first seal portion S1 and a second seal portion S2 are separated. When internal stress is concentrated on a boundary part S3 due to repeated thermal expansion and contraction in a longitudinal direction after mounting a gasket 2 to an engine, the internal stress is absorbed by a slit 2G, and cracking occurs on crack tolerance portions 2H, 2H. Thus cracking on bead portions 2a of an exhaust hole 2C and a suction hole 2D is suppressed, and seal leakage can be prevented.SELECTED DRAWING: Figure 3

Description

The present invention relates to a gasket, and more particularly, to an exhaust manifold gasket that is interposed at a location where an exhaust manifold and an EGR (exhaust gas recirculation) device are connected to a cylinder head and maintains a seal at the connection location.

Conventionally, an EGR device in which a part of exhaust gas is recirculated from an exhaust manifold to an engine is known (for example, Patent Document 1 and Patent Document 2).
A gasket for an exhaust manifold that is interposed between the flange portion of the exhaust manifold and the cylinder head and maintains a seal therebetween is known (for example, Patent Document 3), and the flange portion of the EGR device A gasket for an EGR device that is interposed between the cylinder head and maintains a seal between them is also known (for example, Patent Document 4).

JP2015-63910A JP2015-124729A JP 2013-76352 A JP-A-11-159621

  Conventionally, the exhaust manifold gasket and the EGR device gasket are separated and formed separately, which increases the number of parts during assembly and reduces the mounting work of these gaskets to the cylinder head. There was a problem of becoming complicated.

In view of the circumstances described above, the present invention is adapted to match the position of the first seal portion having a plurality of exhaust holes drilled in accordance with the position of the exhaust hole of the cylinder head and the suction hole for EGR of the cylinder head. A second seal part having a perforated suction hole, a first bead part formed in the first seal part surrounding the exhaust holes, and a second seal surrounding the suction hole. A gasket formed integrally with the first seal portion and the second seal portion, the second bead portion formed on the portion,
An elongated slit in a direction intersecting with a straight line connecting the exhaust hole and the suction hole adjacent to each other is formed at a boundary portion that becomes a connection portion between the first seal portion and the second seal portion, The adjacent portion of the slit in the longitudinal direction is configured as a crack allowing portion.

According to such a configuration, since the gasket that has been conventionally separated into two is integrally formed, the number of parts can be reduced as compared with the conventional one.
Further, after the gasket is attached to the cylinder head, if the gasket is repeatedly expanded and contracted in the longitudinal direction, internal stress concentrates on the boundary portion. At that time, since the slit and the crack permissible portion are formed in the boundary portion, the slit can absorb internal stress and a crack occurs in the crack permissible portion. Thereby, it can suppress that a crack and damage arise in a bead part under the influence of internal stress. Therefore, it is possible to provide a gasket with good sealing performance, although the exhaust manifold and the EGR (exhaust gas recirculation) device are integrated.

1 is a schematic perspective view showing an embodiment of the present invention. The front view of the principal part of FIG. The front view of the gasket of FIG. Sectional drawing of the principal part which follows the III-III line | wire of FIG. Sectional drawing of the principal part which follows the IV-IV line | wire of FIG. The enlarged view of the principal part of FIG. The enlarged view for showing the effect | action of the principal part of FIG. The front view which shows 2nd Example of this invention. The front view which shows 3rd Example of this invention.

Hereinafter, the present invention will be described with reference to the illustrated embodiment. FIG. 1 shows a main part of an automobile engine, and a flange portion of an exhaust manifold 3 with a gasket 2 interposed on a side wall 1A (end surface) of a cylinder head 1. The flange portion 4 </ b> A of the 3 </ b> A and the EGR device 4 is connected by a plurality of fastening bolts 5. By sandwiching the gasket 2 between the side wall 1A and the flange portions 3A and 4A, the seal between the side wall 1A and the flange portions 3A and 3B is maintained.
The side wall 1A of the cylinder head 1 is formed with a trapezoidal first protruding flat portion 1a, and a substantially circular second protruding flat portion 1b is formed at an adjacent position. Both projecting flat portions 1a and 1b are formed so as to have the same dimension as the original surface of the side wall 1A. The surfaces (seal surfaces) of both protruding flat portions 1a and 1b are flat surfaces and are located on the same plane. Since the protruding flat portions 1a and 1b are formed apart from each other, a groove-like shape is formed between one end (left end in the drawing) of the first protruding flat portion 1a in the longitudinal direction and the second protruding flat portion 1b. A space 1C is formed.
Four exhaust holes 6 are opened in the first projecting flat portion 1a at equal pitches in the lateral direction (horizontal direction), and exhaust gas recirculated by the EGR device 4 is supplied to the second projecting flat portion 1b. A suction hole 7 for introduction is opened.
A total of five fastening bolts 5 are arranged in a staggered manner in the first projecting flat portion 1 a at positions adjacent to the exhaust holes 6. Further, a pair of fastening bolts 5 are disposed on both sides of the second projecting flat portion 1b with the suction hole 7 in between. The gasket 2 is attached to the surfaces (seal surfaces) of the two protruding flat portions 1a and 1b, and the flanges 3A and 4A are brought into contact with the gasket 2 in this state, and then tightened with the fastening bolts 5.

As shown in FIGS. 1 and 2, the exhaust manifold 3 includes a substantially trapezoidal flange portion 3A, four branch pipes 3B connected to the flange portion 3A at an equal pitch, and those branch pipes 3B. And an exhaust pipe 3C to be joined together.
The flange portion 3A is formed in a trapezoidal shape according to the contour of the first protruding flat portion 1a, and the ends of the four branch pipes 3B are opened in the flange portion 3A according to the positions of the exhaust holes 6. doing. The surface (seal surface) of the flange portion 3A is a flat surface, and five bolt holes 3D are formed in the flange portion 3A in accordance with the position of the fastening bolt 5 of the first protruding flat portion 1a. ing.
When the exhaust manifold 3 is connected to the first projecting flat portion 1a by the fastening bolt 5 through the gasket 2, the exhaust gas discharged from each exhaust hole 6 can be discharged to the outside through the branch pipe 3B and the exhaust pipe 3C. It is like that.
Next, the EGR device 4 includes a flange portion 4A adapted to the shape of the second projecting flat portion 1b, and a recovery tube 4B having one end connected to the exhaust pipe 3C and the other end opened to the flange portion 4A. And. The surface (seal surface) of the flange portion 4A is a flat surface, and a pair of bolt holes 4C are formed in the flange portion 4A in accordance with the position of the fastening bolt 5 of the second protruding flat portion 1b. ing.
The flange portion 3A of the exhaust manifold 3 and the flange portion 4A of the EGR device 4 are separated from each other, but their surfaces (seal surfaces) are configured to be on the same plane. The two flanges 3A and 4A positioned on the same plane as described above are opposed to the surfaces (seal surfaces) of the two protruding flat portions 1a and 1b of the cylinder head 1.

Next, as shown in FIGS. 3 to 5, the gasket 2 of the present embodiment is formed in a horizontally elongated substantially strip shape as a whole so that it can be mounted over both projecting flat portions 1 a, 1 b on the cylinder head 1 side. ing. The outline of the gasket 2 has a shape that follows the outline extending over both protruding flat portions 1a and 1b on the cylinder head 1 side.
The gasket 2 of the present embodiment is configured by superposing two metal substrates 2A and 2B having the same shape, and the upper and lower metal substrates 2A and 2B are integrally connected by caulking those required portions.

In the gasket 2, four exhaust holes 2C are formed in accordance with the positions and sizes of the four exhaust holes 6, and a position on one end side in the longitudinal direction (left end in FIG. 3). The suction hole 2D is formed in accordance with the position and size of the suction hole 7.
Bead portions 2a and 2b are formed at the overlapping positions of the upper and lower metal substrates 2A and 2B surrounding each exhaust hole 2C (FIG. 4). These bead portions 2a and 2b are formed so as to be inclined so that the inner peripheral edges are separated from each other when viewed in a radial cross section. Similarly to these, bead portions 2a and 2b are formed at the overlapping positions of the upper and lower metal substrates 2A and 2B surrounding the suction hole 2D (FIG. 5).
As described above, the bead portions 2a and 2b are formed so as to surround the exhaust holes 2C and the suction holes 2D, so that the gasket 2 is located between the protruding flat portions 1a and 1b and the flange portions 3A and 4A. So that the bead portions 2a and 2b are in close contact with the mating member so that the seal between the projecting flat portions 1a and 1b and the flange portions 3A and 4A is maintained. It has become.

A region in contact with the first projecting flat portion 1a in the gasket 2 is the first seal portion S1 for the exhaust manifold 3, and a region in contact with the second projecting flat portion 1b in the gasket 2 is the second for the EGR device 4. It is a seal portion S2. That is, in the gasket 2 of the present embodiment, the first seal portion S1 for the exhaust manifold 3 and the second seal portion S2 for the EGR device 4 are configured continuously and integrally.
Bolt holes 2E are drilled in a total of five locations in the first seal portion S1 in accordance with the positions of the fastening bolts 5 of the first protruding flat portion 1a. These bolt holes 2E are formed in a staggered position across the exhaust hole 2C. In addition, a pair of bolt holes 2F are formed in the second seal portion S2 in accordance with the positions of the pair of fastening bolts 5 of the second projecting flat portion 1a. That is, a pair of bolt holes 2F is formed with the suction hole 2D interposed therebetween.

In the present embodiment, on the premise of the configuration of the gasket 2 described above, the boundary portion S3 serving as a connection portion between the first seal portion S1 and the second seal portion S2 is in a direction intersecting the longitudinal direction of the entire gasket 2. A slit 2G made of an elongated hole is formed. The slit 2G is formed in the same shape at the overlapping position of the two metal substrates 2A and 2B.
The longitudinal direction of the slit 2G is a direction that intersects the longitudinal direction of the entire gasket 2. More specifically, the longitudinal direction of the slit 2G is a direction intersecting with a straight line connecting the centers of the exhaust hole 2C and the suction hole 2D adjacent to each other with the boundary portion S3 interposed therebetween.
Adjacent portions at both ends in the longitudinal direction of the slit 2G are left as residual connection portions that connect the first seal portion S1 and the second seal portion S2, and the residual connection portions at these two locations serve as crack allowable portions 2H. ing.
The slit 2G is formed in an elongated triangular shape, and the maximum width on the center side of the slit 2G is slightly smaller than the inner diameter of the bolt holes 2E and 2F. The length of the crack allowing portion 2H in the direction intersecting with the longitudinal direction of the gasket 2 is about half the inner diameter of the bolt holes 2E and 2F.
When the gasket 2 is mounted on and attached to both projecting flat surfaces 1a and 1b of the cylinder head 1, a boundary portion S3 of the gasket 2 and a slit 2G therefor are formed in the space 1C between the projecting flat surfaces 1a and 1b. The crack allowing portion 2H is positioned (see FIG. 7).
Thereby, after the gasket 2 is attached to the cylinder head 1, when the internal stress is concentrated on the boundary portion S3 between the two seal portions S1 and S2, the internal stress can be absorbed by the slit 2G and is shown by an imaginary line in FIG. A crack is generated at the position, that is, the crack allowable portion 2H. Thereby, when internal stress is concentrated on the boundary portion S3, it is possible to prevent the exhaust hole 2C and the bead portions 2a and 2b of the suction hole 2D adjacent to each other across the boundary portion S3 from being cracked or damaged. It is like that.
As described above, in the gasket 2 of the present embodiment, the first seal portion S1 for the exhaust manifold 3 and the second seal portion S2 for the EGR device 4 are integrated, and the boundary portion S3 thereof is also formed. A feature is that a slit 2G and a crack allowing portion 2H are formed.

As shown in FIG. 1, the gasket 2 of the first embodiment having the above configuration is superposed on both projecting flat portions 1 a and 1 b of the cylinder head 1 after inserting the fastening bolt 5 into the bolt holes 2 </ b> E and 2 </ b> F, In that state, the flange portion 3A of the exhaust manifold 3 and the flange portion 4A of the EGR device 4 are superposed on the gasket 2 from the outside, and then both flange portions 3A, 4A are made into both projecting flat portions 1a, 1b by fastening bolts 5. Link. Accordingly, the gasket 2 is sandwiched between the projecting flat portions 1a and 1b and the flange portions 3A and 4A so as to maintain a seal therebetween. In the state after the completion of the attachment, the boundary portion S3 of the gasket 2 and the slit 2G and the crack allowing portion 2H provided therein are positioned in the space portion 1C between the two protruding flat portions 1a and 1b of the cylinder head 1. It has become.

As described above, in the gasket 2 of the present embodiment, the first seal portion S1 for the exhaust manifold 3 and the second seal portion S2 for the EGR device 4 are continuously and integrally configured. Therefore, compared with the conventional product in which the first seal portion S1 and the second seal portion S2 are separated, the number of parts can be reduced by one, and the labor for mounting the gasket 2 on the cylinder head 1 can be reduced. Can be made.
In addition, after the gasket 2 and the flange portions 3A and 4A are attached to the cylinder head 1, the engine 2 is repeatedly operated and stopped, whereby the gasket 2 is mainly attached to the first protruding flat portion 1a. The seal portion S1 repeats thermal expansion and contraction in the longitudinal direction. At that time, as shown in FIGS. 3, 6, and 7, the fastening bolt 5 for the EGR device 4 is positioned next to the boundary portion S3, so that the first seal portion S1 is elastically deformed in the longitudinal direction. Will be restrained. For this reason, the internal stress is concentrated on the boundary portion S3 facing the space 1C. However, the internal stress is absorbed by the slit 2G in the boundary portion S3, and a crack is generated in the crack allowing portion 2H. Therefore, it is possible to prevent cracking or damage to the bead portions 2a and 2b of the exhaust hole 2C and the suction hole 2D adjacent to the boundary portion S3 due to the internal stress acting on the boundary portion S3. Thereby, it is possible to effectively suppress the occurrence of seal leakage in the gasket 2.

Next, FIG. 8 shows a second embodiment relating to the gasket 2. In this second embodiment, the slit 2G is formed of a wide linear hole. Other configurations are the same as those of the first embodiment, and the same member numbers are assigned to the corresponding members.
FIG. 9 shows a third embodiment relating to the gasket. In this third embodiment, the slit 2G is formed of a square-shaped hole. Other configurations are the same as those of the first embodiment, and the same member numbers are assigned to the corresponding members. Even in the second and third embodiments having such a configuration, the same operation and effect as the first embodiment can be obtained.
In each of the above embodiments, the gasket 2 is formed by polymerizing two metal substrates 2A and 2B, but a gasket may be formed by polymerizing three or more metal substrates.

DESCRIPTION OF SYMBOLS 1 ... Cylinder head 1A ... Side wall 2 ... Gasket 2C ... Exhaust hole 2D ... Intake hole 2G ... Slit 2H ... Crack acceptance part 3 ... Exhaust manifold 4 ... EGR (device) 6 ... Exhaust hole 7 ... Intake hole S1 ... First Seal part S2 ... Second seal part S3 ... Boundary part

Claims (2)

A first seal portion having a plurality of exhaust holes drilled in accordance with the position of the exhaust hole of the cylinder head, and a first seal portion having a suction hole drilled in accordance with the position of the EGR suction hole of the cylinder head. Two seal portions; a first bead portion formed in the first seal portion surrounding each exhaust hole; a second bead portion formed in the second seal portion surrounding the suction hole; A gasket formed integrally by connecting the first seal portion and the second seal portion,
An elongated slit in a direction intersecting with a straight line connecting the exhaust hole and the suction hole adjacent to each other is formed at a boundary portion that becomes a connection portion between the first seal portion and the second seal portion, A gasket characterized in that a portion adjacent to an end portion in the longitudinal direction of the slit is configured as a crack allowing portion.   The gasket is formed by polymerizing a plurality of metal substrates, and the slit is formed at the same position of the plurality of metal substrates, and the shape of the slit is substantially a triangle, a wide linear shape, or a square shape. The gasket according to claim 1, wherein the gasket is any one of the following.

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