JPH05306778A - Gasket - Google Patents

Abstract

PURPOSE:To provide the gasket, which can previously prevent the nonconformity of formation of a projection at the time of manufacture and which can secure the stabilized sealing property. CONSTITUTION:In the seal surface S1 of a gasket 5, an annular sealing projection 16 is formed in the periphery of an opening part 15. Distortion absorbing annular grooves 17 are formed in both the inside and outside of the projection 16. This groove 17 is formed with intermittent parts shallower than other parts. At the time of manufacturing the gasket 5, for example, in the case where a first insert 10 is displaced upward, a clearance between the first insert 10 and the lower surface of a fitting for forming the groove 17 is narrowed, but since the fitting is formed so as to form shallow parts of the groove 17, a wide clearance is formed between the first insert 10 and the lower surface of the fitting. Unvulcanized rubber is therefor flowed through this wide clearance, and filled in a space for forming a projection 16 securely.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a gasket interposed between an engine cylinder head and an intake manifold.

[0002]

2. Description of the Related Art Conventionally, as shown in FIG. 8, an intake manifold 33 is attached to the intake side of a cylinder head 31 of an engine, for example, by a bolt 34 via a gasket 32 made of rubber. The gasket 32 absorbs vibration and noise generated in the cylinder head 31, and seals between the cylinder head 31 and the intake manifold 33.
The gasket 32 includes a head side portion 35 located on the cylinder head 31 side and a manifold side portion 36 located on the intake manifold 33 side. An insert 37 is embedded in the head side portion 35 in the vicinity of the seal surface S3. An insert 38 is embedded in the manifold side portion 36 in the vicinity of the seal surface S4. Gasket 3 with both inserts 37 and 38
2 is reinforced so that a sealing property can be obtained.

The gasket 32 is formed with an opening 39 which connects the passage 31a of the cylinder head 31 and the passage 33a of the intake manifold 33. On the upper and lower sealing surfaces S3, S4 of the gasket 32, annular sealing protrusions 40 are provided so as to surround the opening 39. Further, as shown in FIG. 9, annular strain absorbing grooves 41 are provided on both inner and outer sides of the protrusion 40. When the protrusion 40 is compressed, the strain of the protrusion 40 due to stress concentration is absorbed in the groove 41.

[0004]

However, in the gasket 32 described above, both inserts 37 and 38 need to be embedded in the vicinity of the respective seal surfaces S3 and S4 in order to secure their strength and ease of handling. is there. For this reason,
When the gaskets 32 are manufactured, as shown in FIG. 10, when the positions of the inserts 37 and 38 (only the insert 38 is shown in FIG. 10) are vertically displaced, the insert 38 and the groove 41 are removed. There is a risk that the gap d between the lower surface 42a of the mold 42 for forming the gap is very narrow. When the gap d between the insert 38 and the lower surface 42a of the mold is narrowed in this way, the flow of unvulcanized rubber flowing in the direction of the arrow X in the drawing is obstructed in the mold 42, and the protrusion 40 is removed. It becomes difficult for the unvulcanized rubber to be sufficiently filled in the space for forming it. As a result, there is a problem that defective molding occurs in the protrusion 40.

The present invention has been made in order to solve the above problems, and its purpose is to prevent molding defects of protrusions during manufacturing and to ensure stable sealing performance. To provide a possible gasket.

[0006]

In order to achieve the above object, the present invention interposes between a cylinder head and an intake manifold, and an opening for communicating the cylinder head and the intake manifold is provided on a sealing surface. An annular sealing protrusion formed so as to surround the annular protrusion and an annular strain absorbing groove formed on both inner and outer sides of the protrusion, and a gasket formed by embedding a reinforcing insert in the vicinity of the sealing surface. The gist of the invention is to intermittently provide at least a part of the groove with a shallower depth than that of the other part.

[0007]

Therefore, according to the above structure, the gasket having the reinforcing insert buried in the vicinity of the sealing surface is interposed between the cylinder head and the intake manifold. On each sealing surface of the gasket, an annular sealing projection is formed so as to surround the opening communicating between the cylinder head and the intake manifold. When the projection receives compressive stress and is distorted, the gasket and the cylinder head are distorted. And between the gasket and the intake manifold. Further, the strain of the protrusion generated at this time is absorbed by the annular strain absorbing grooves formed on the inner and outer sides of the protrusion.

At least a part of the groove is intermittently provided with a portion having a depth smaller than that of the other part. Therefore, even if the insert is misaligned during the manufacture of the gasket and the gap between the insert and the bottom surface of the groove is narrowed, the unvulcanized rubber forms a portion having a shallower depth than other parts. It smoothly flows in the space for forming and reliably fills the space for forming the protrusion.

[0009]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment in which the present invention is embodied in a gasket interposed between a cylinder head of a V-type engine and an intake manifold will be described below with reference to FIGS.

As shown in FIG. 2, the V-type engine 1 has a plurality of cylinders, and the cylinders are divided into two banks 2. Each bank 2 is arranged in a V shape around the crankshaft, and the space sandwiched by the banks 2 is a valley 2a. In the cylinder head 3 of each bank 2, a mounting portion 4 is provided so as to project obliquely upward on the side facing the valley portion 2a. An intake manifold 6 is attached to each mounting portion 4 via a rubber gasket 5.
Is installed. The gasket 5 is attached to each mounting portion 4
Is to seal between the intake manifold 6 and each intake manifold 6, and to absorb vibration and noise generated inside the cylinder of the V-type engine 1. A surge tank 7 for suppressing intake air pulsation is connected to the tip of the intake manifold 6.

As shown in FIGS. 3 and 4, the gasket 5 is
The head side portion 8 located on the cylinder head 3 side (see FIG.
2) and a manifold side portion 9 located on the intake manifold 6 side (upper side in FIG. 4). The manifold side portion 9 is provided with a first reinforcing insert 10. The first insert 10 is made of a metal plate having a thickness of about 2 mm. The manifold side portion 9 is provided with through holes 11 penetrating the first insert 10 at a plurality of locations (six locations in this embodiment).

Further, the head side portion 8 is provided with a second insert 12 made of a plate-like body like the first insert 10. The head side portion 8 has a second
Through holes 13 penetrating the insert 12 are provided at a plurality of locations (four locations in this embodiment). Then, in these through holes 13, stud pipes 14 projecting obliquely upward are provided.
(See FIG. 3) is erected. More specifically, the stud pipe 14 extends along the central angle direction of the bank angle when the gasket 5 is attached to the cylinder head 3.

As shown in FIGS. 3 and 4, the gasket 5 has an opening 1 that opens to the passage of the intake manifold 6 and the passage of the mounting portion 4 of the cylinder head 3.
5 is formed.

Further, as shown in FIGS. 5 and 6, in both sealing surfaces S1 and S2 of the gasket 5 (only the upper sealing surface S1 is shown in FIGS. 5 and 6), an annular shape is provided around the opening 15. A protrusion 16 for sealing is formed. The projection 16 projects from the sealing surface S1 by 0.5 mm. Annular strain absorbing grooves 17 are formed on both inner and outer sides of the protrusion 16. The groove 17 is formed to have a depth of 0.5 mm. Further, for example, in a portion having a small radius of curvature of the opening 15, as shown in FIG. 1, a portion having a depth smaller than 0.2 mm is intermittently formed. However, the protrusion 16 and the groove 1
7 is formed such that the sum of the recessed volumes of the groove 17 from the seal surface S1 is larger than the sum of the protruding volumes of the protrusions 16 from the seal surface S1. It can be absorbed.

To mount the gasket 5, the manifold side portion 9 of the gasket 5 is first placed on the intake manifold 6. Next, the first insert 10
The gasket 5 is fixed to the intake manifold 6 by inserting a bolt through the through hole 11 and tightening. Then, the head side portion 8 of the gasket 5 is attached to the mounting portion 4
On top of. Then, the bolt is inserted into the stud pipe 14 and tightened. In this way, the gasket 5 is interposed between the mounting portion 4 of the cylinder head 3 and the intake manifold 6. Then, due to the tightening, the protrusions 16 on both the seal surfaces S1 and S2 receive compressive stress and are distorted, and the strain is absorbed by the groove 17. By this action, the mounting portion 4 of the cylinder head 3 and the gasket 5 are
And the intake manifold 6 and the gasket 5 are reliably sealed.

Next, a method of manufacturing the gasket 5 will be described. First, as shown in FIG. 7, a mold 19 having a cavity 18 for molding the gasket 5 is prepared. Then, the first (and second) insert 10 (12) is installed at a predetermined position in the cavity 18, and unvulcanized rubber is introduced into the cavity 18 through a gate (not shown) (on the left side in FIG. 7). To do. Then, the unvulcanized rubber flows from the left side to the right side as indicated by an arrow Y in the figure.

At this time, if the first insert 10 is temporarily used,
In the case where the first insert 10 is displaced upward, the gap d between the first insert 10 and the die lower surface 19a for forming the groove 17 becomes narrow. However, in this embodiment, since the mold 19 is formed so as to form a shallow portion of the groove 17, a gap wider than the gap d is formed between the first insert 10 and the mold lower surface 19a. d1 is formed.
Therefore, the unvulcanized rubber flows through the gap d1 and is reliably filled in the space for forming the protrusion 16. Then, the unvulcanized rubber is subjected to a vulcanization treatment and taken out from the mold 19, whereby the gasket 5 is obtained.

As described above, in this embodiment, the annular strain absorbing grooves 17 are formed on both the inner and outer sides of the protrusion 16, and the groove 17 is intermittently provided with a portion having a shallower depth than the other portions. To form. Therefore, when the gasket 5 is manufactured, the unvulcanized rubber flows smoothly through the wide gap d1 even when the positions of the first and second inserts 10 and 12 are displaced. Therefore, the protrusion 16
The unvulcanized rubber can be surely filled in the space for forming the mold, and the occurrence of molding defects can be prevented in advance. Then, by using the gasket 5 having no such molding defect, stable sealing performance can be secured.

The present invention is not limited to the above-mentioned embodiments, but can be implemented as follows by appropriately modifying a part of the configuration without departing from the spirit of the invention. (1) In the above-described embodiment, the shallow portion of the groove 17 of the gasket 5 is intermittently provided at a location having a small radius of curvature, but it may be provided at all locations of the groove 17. Good.

(2) In the above embodiment, the gasket 5 interposed between the cylinder head 3 of the V-type engine 1 and the intake manifold 6 is adopted, but in addition to that, the gasket 5 is embodied as a gasket for an in-line engine. May be.

(3) In the above embodiment, the height of the protrusion 16 is 0.5 mm from the sealing surface S1 and the depth of the groove 17 is 0.
5 mm and 0.2 mm, but the height of the protrusion 16 and the groove 1
The depth of 7 is not particularly limited to the above numerical value, and may be appropriately changed depending on the size, function, etc. of the gasket 5.

[0022]

As described in detail above, according to the gasket of the present invention, it is possible to prevent defective molding of protrusions during manufacturing and to ensure stable sealing performance. Play.

[Brief description of drawings]

FIG. 1 is a partial perspective view showing a groove of a gasket in an embodiment embodying the present invention.

FIG. 2 is a schematic view of an upper portion of a V-type engine in one embodiment.

FIG. 3 is a plan view of a gasket according to an embodiment.

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

FIG. 5 is a partial cross-sectional view showing a protrusion and a groove in one embodiment.

FIG. 6 is a partial cross-sectional view showing a shallow portion of a protrusion and a groove in one embodiment.

FIG. 7 is a cross-sectional view of a mold showing an operation of manufacturing a gasket in one embodiment.

FIG. 8 is a sectional view showing a mounting state of a gasket according to a conventional technique.

FIG. 9 is a partial perspective view showing a groove of a gasket according to a conventional technique.

FIG. 10 is a cross-sectional view of a mold for explaining a problem at the time of manufacturing a gasket according to a conventional technique.

[Explanation of symbols]

3 ... Cylinder head, 6 ... Intake manifold, 1
0 ... 1st insert, 12 ... 2nd insert, 15
... Aperture, 16 ... Protrusion, 17 ... Groove, S1 ... Seal surface, S
2 ... Sealing surface.

Claims (1)

[Claims] 1. A seal surface (S1, S) which is interposed between a cylinder head (3) and an intake manifold (6).
In 2), an annular sealing protrusion (16) is formed so as to surround an opening (15) that communicates the cylinder head (3) and the intake manifold (6), and both inner and outer sides of the protrusion (16). And an annular strain absorbing groove (17) formed on the sealing surface (S1, S2)
In a rubber gasket in which reinforcing inserts (10, 12) are embedded in the vicinity of the groove, at least a part of the groove (17) is intermittently provided with a shallower depth than the other. Gasket characterized by.