JPH0613429Y2 - Metal gasket - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial field of application] The present invention relates to a head gasket of an automobile engine and other metal gaskets, in which the sealing characteristics are deteriorated at the top surface of the bead crossing portion for sealing formed on the gasket. The present invention relates to an improved metal gasket.

[Conventional technology]

Conventionally, as a metal gasket, there is, for example, one whose main part is shown in FIG. In this gasket, the sealing bead portion b is formed by surrounding the sealed portion on the surface of the elastic metal thin plate a. However, depending on the state of the sealed portion, the sealing bead portion b crosses at a right angle and so on. Intersecting portion c occurs.

However, at the bead crossing portion c, a problem may occur due to sealing characteristics. That is, when a bead portion b having the same groove width is connected to another bead portion b in an orthogonal state or at an appropriate angle to form an intersecting portion c as shown in the figure, the intersecting portion top surface d is formed.
Therefore, there is a problem in terms of sealing characteristics. In this state, for example, the pressure-sensitive test paper is normally provided with the bead crossing portion c as shown in FIG. 5 and the bead crossing portion top surface d as shown in the drawing having the same bead groove bottom face b'width. When the beads are attached according to the method and pressed from the upper and lower surfaces, a part which becomes slightly thin on the top surface d of the bead crossing portion, that is, a portion which causes a problem in sealing characteristics with respect to the surface of the sealed portion is generated. It is found by the parentheses in the figure. When the metal gasket is actually used, the bead crossing portion top surface d
Although there is no problem in the degree of deterioration of the sealing characteristics in the above, it is necessary to improve the sealing characteristics on the top surface d of the bead intersecting portion c in order to obtain more complete sealing characteristics.

Therefore, in JP-A-58-149467, by forming a narrowed portion in which the general bead portion is gradually narrowed as it approaches the bead crossing portion, the spring constant at the bead crossing portion is made larger than that in the general bead portion. There is described a metal gasket which is set to improve the sealing property of the bead crossing portion.

On the other hand, JP-A-61-255250 and JP-A-62-1
In Japanese Patent No. 55375, the width of the bead portion is narrowed and the spring constant is increased as the distance from the bolt fastening portion increases,
A metal gasket in which the pressure contact force of the bead portion is made uniform to improve the sealing property is described.

[Problems to be solved by the device]

By the way, the applicant of the present invention, as a cause of the deterioration of the sealing property at the bead crossing portion, has a rounded portion e at the bead crossing portion.
When the radius c of the bead portion b is set to be small and the width c ′ of the groove bottom surface b ′ of the bead portion b is set to the same width to form the intersecting portion c, a metal thin plate is taken at the rounded portion e and a metal thin plate is formed on the top surface d of the bead intersecting portion. Is not sufficiently transferred, that is, the forming accuracy in the height direction of the bead intersecting portion top surface d is reduced, and by increasing the surface area at this intersecting portion c, the groove bottom surface e of the bead intersecting portion is increased. Widen the width of the bead crossover surface d
It has been found that this problem can be solved by increasing the molding accuracy in the height direction of.

However, in the metal gaskets described in the above three publications, basically, the portion where the pressure contact force of the bead portion is reduced is configured to be narrow, and the spring constant of the bead portion is increased to increase the pressure contact force. Since it is configured to improve the sealing property, as described in JP-A-58-149467, when a narrowed portion in which the general bead portion is gradually narrowed as it approaches the bead crossing portion is formed, When press molding the part, the meat of the top surface of the drawing part is taken in the groove hypotenuse, the height of the top surface of the drawing part becomes a little lower than the designed value, and the sealing property in the drawing part is reduced. The problem of lowering occurs.

[Means for Solving the Problems]

The metal gasket according to the present invention is a metal gasket prepared by press-molding a sealing bead portion surrounding a sealed portion on a thin metal plate having elasticity similar to a sealing surface, wherein a bead crossing portion of the sealing bead portion is formed. The width of the groove bottom is made larger than the width of the groove bottom of the general bead part other than the bead crossing part, and the height of the top surface of the bead crossing part is set to be the same as the height of the top surface of the general bead part. In order to form the bead crossing portion in this way, the radius of the curved rounded portion of the bead crossing portion connected to the groove hypotenuse of the general bead portion is set to be 1/2 or more of the width of the general bead portion, or the general bead portion. The width of the bottom surface of the groove was increased toward the bead intersecting portion, or the general bead portion reaching the bead intersecting portion was formed in a linear state with a length four times or more the width of the other ordinary bead portions.

[Action]

As described above, in the metal gasket according to the present invention, the groove bottom width of the bead crossing portion is made larger than the groove bottom widths of the other bead portions, so that the bead portion is formed by press molding on the metal thin plate. At this time, even if the thin metal plate on the top surface of the bead crossing part is taken on the groove oblique side of the bead crossing part, it is possible to reliably obtain the designed height at the center of the top surface of the bead crossing part. Therefore, without changing the molding die of the press molding machine, the molding accuracy in the height direction at the top surface of the bead crossing part is improved and the top surface of the bead crossing part is set to the same height as the top surface of the general bead part. A sufficient sealability can be secured at the bead crossing portion.

〔Example〕

 Hereinafter, the present invention will be described in detail with reference to illustrated embodiments.

FIG. 1 is a state view of a part of a metal gasket according to the present invention seen from the bottom surface, in which 1 is a thin metal plate, such as a stainless steel plate, having a shape close to a sealing surface and having elasticity, which constitutes a main body of the metal gasket. The bead portion 3 for sealing is created by surrounding the sealed portion 2. This bead part 3
As shown in the figure, a ridge is formed on one surface of the thin metal plate 1 and a groove is formed on the other surface, so that a metal gasket can be sealed on both surfaces. In this bead portion 3 for sealing,
There may be a bead crossing portion as shown by 4 in the drawing. The present invention is directed to the top surface 4'of the bead crossing portion 4 as described above.
It is intended to provide a good bead crossing portion 4 in which the problem of the sealing characteristics as described above in 1) is improved. Reference numeral 5 in FIG. 1 denotes a groove constituting such a bead portion 3,
The groove 5 is composed of a groove bottom surface 6 and a groove hypotenuse 7. The bead portion 3 is formed by a pressing operation of a female die and a male die for pressing so as to surround the sealed portion 2 with respect to one sheet of metal sheet 1 in a conventional manner. The width of the groove bottom surface 6 of the bead crossing portion 4 is made larger than the width of the groove bottom surface 6 of the other general bead portion 3 to improve the sealing property at the top surface 4'of the bead crossing portion 4. In order to make the width of the groove bottom surface 6 of the bead crossing portion 4 larger than the width of the groove bottom surface 6 of the other general bead portion, for example, as shown in FIG. Part 3
By setting it to be 1/2 or more of the width T of
Since it is possible to form the groove bottom surface 6 having a wider width than that when the radius is less than / 2, the bead crossing portion top surface 4'at the back position of the groove bottom surface 6 is in a wide state,
At the time of press molding, the height of the bead crossing portion 4 can be set to be the same as the height of the top surface of the other general bead portion 3 to improve the sealing characteristics, that is, the same as the top surface of the other general bead portion 3. The sealing property can be obtained.

As described above, the deterioration of the sealing characteristic at the bead crossing portion top surface 4'is caused by the existence of the rounded portion 8 formed when the bead portions 3 and 3 cross each other, so that the rounded portion 8 approaches a state close to an acute angle. For example, the meat for forming the bead crossing portion 4 is taken in this portion, and the height of the bead crossing portion top surface 4 ′ cannot be obtained. However, the radius R of the rounded portion 8 is equal to the width T of the bead portion 3. It has been found that the height of the bead crossing portion top surface 4'is maintained in actual molding by setting it to 1/2 or more. Further, in order to increase the width of the groove bottom surface 6 of the bead crossing portion 4, for example, the width of the groove bottom surface 6 of the general bead portion reaching the bead crossing portion 4 is gradually increased so that the bead crossing portion 4 is changed to the other general bead portion 3. When the width of the bead crossing portion is set larger than that of the bead crossing portion 4 by setting the groove bottom surface 6'in the state as shown in FIG. It is possible to obtain the desired height of 4 '. Therefore, in such a case, the oblique side 7 of the groove in the bead crossing portion 4 has a steeper angle than the other portions. Furthermore, in addition to increasing the width of the groove bottom surface 6 of the bead crossing portion 4, or separately from these, as shown in FIG.
By setting the bead portion 3 reaching the bead crossing portion 4 in a straight line in a range of a length L which is at least 4 times the width T of the bead portion 3, preferably at least 5 to 7 times, the bead crossing portion 4 is formed.
It has been found that the height of the top surface 4'at the height of 4 can be obtained, and desired sealing characteristics can be obtained. That is, the sealing characteristics of the bead crossing portion top surface 4'formed by crossing the general bead portions 3 with each other are as shown in FIG. Since the height of the bead crossing portion top surface 4 ′ is not required as a cause of the defective seal portion in the inspection with the pressure sensitive test paper, That is, the sealing characteristics have been improved.

[Effect of device]

As described above, in the metal gasket according to the present invention, (1) the groove bottom width of the bead crossing portion is set to be larger than the groove bottom widths of other bead portions, and it is changed to the molding die of the press molding device. Without increasing the height of press molding in the height direction of the bead crossing part top surface, the height of the bead crossing part top surface and the general bead part top surface can be set to be the same, and the sealing property at the bead crossing part can be improved. It is possible to increase the sealing characteristics and make the sealing characteristics uniform.

(2) In order to widen the groove bottom width of the bead intersecting portion, the radius of the bead intersecting portion is set to 1/2 or more of the bead portion width to easily increase the groove bottom width. Yes, and by gradually increasing the groove bottom width of the general bead reaching the bead crossing part and making the bead crossing part the maximum width, molding is easy and the height of the bead crossing part top surface can be easily obtained. In addition, the bead crossing portion having more effective seal characteristics can be obtained by using the radius of the bead crossing portion in combination with the setting.

(3) Further, the bead portion reaching the bead crossing portion has a bead width of 4
By making a straight line with a length more than twice, and by overlapping with the groove bottom width of the bead crossing portion and the relationship of the rounded portion,
The width of the groove bottom surface of the bead crossing portion can be increased to obtain the height of the top surface of the bead crossing portion, and a good sealing characteristic can be obtained.

[Brief description of drawings]

FIG. 1 is a bottom view of a main part of a metal gasket according to the present invention,
FIG. 2 is a plan view of FIG. 1, FIG. 3 is a seal characteristic diagram showing a state where the metal gasket of FIG. 1 is used and the seal characteristic is tested by a pressure sensitive test paper, and FIG. 4 is a conventional metal gasket. FIG. 5 is a bottom view of an essential part of FIG. 5, FIG. 5 is a perspective view for explaining a state where the bead crossing portion of FIG. 4 is enlarged, and FIG. It is the sealing characteristic diagram shown. 1: Metal thin plate, 2: Sealed part, 3: Bead part, 4: Bead crossing part, 4 ': Bead crossing part top surface, 5 groove, 6: groove bottom surface, 6': enlarged groove bottom surface, 7: groove Hypotenuse, 8: R section,
4a: Seal of bead crossing part, 3a: Seal of general bead part.

 ─────────────────────────────────────────────────── ─── Continuation of front page (72) Yoshitaka Abe, 2-6-5, Runi, Toyonaka-shi, Osaka Prefecture, Japan Domestic Products Co., Ltd. (72) Toshiki Takatori 2--6, Runi, Toyonaka, Osaka Prefecture (56) Reference JP-A-58-149467 (JP, A) JP-A-62-155375 (JP, A) JP-A-61-255250 (JP, A)

Claims (4)

[Scope of utility model registration request] 1. A metal gasket in which a sealing bead portion surrounding a sealed portion is formed by press molding on a thin metal plate having elasticity similar to a sealing surface, wherein a groove bottom surface of a bead crossing portion of the sealing bead portion is formed. The metal is characterized in that the width is made larger than the width of the groove bottom surface of the general bead portion other than the bead intersection portion, and the height of the top surface of the bead intersection portion is set to be the same as the height of the top surface of the general bead portion. gasket. 2. The radius of the curved rounded portion of the bead crossing portion connected to the oblique side of the groove of the general bead portion is set to the width of the general bead portion.
The metal gasket according to claim 1, characterized in that the metal gasket is set to 1/2 or more. 3. The metal gasket according to claim 1 or 2, wherein the width of the bottom surface of the groove of the general bead portion is increased toward the bead crossing portion. 4. The utility model registration claim 1 or claim 2 characterized in that the general bead portion reaching the bead crossing portion is linearly formed with a length of four times or more the width of the other general bead portion. The metal gasket according to item 2 or 3.