JP3364577B2 - 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 gasket, and more particularly to a gasket suitable for use as a cylinder head gasket.

[0002]

2. Description of the Related Art As shown in FIG. 3, in a known gasket, a flat plate-shaped main body 51 is provided with a bead-shaped seal portion 52 on its inner peripheral edge, which generates a surface pressure when it is sandwiched by a mounting member.
In the outer shape (planar layout), a required number (four in the figure) of bolt insertion portions 53 having a substantially circular hole shape in a plane are provided.

Therefore, in this gasket, the flat plate main body 51 is provided with a required number of bolt insertion portions 53 having a substantially circular hole shape in the flat surface within the outer shape of the flat plate main body 51.
However, the tightening load acting on the gasket at the time of mounting is widely dispersed in a plane, so that the surface pressure generated in the seal portion 52 is greatly reduced. There is a disadvantage that it does not grow.

[0004]

SUMMARY OF THE INVENTION In view of the above points, the present invention prevents the tightening load from widely spreading in a flat state at the time of mounting, increases the surface pressure of the seal portion, and thus has excellent sealability. It is an object of the present invention to provide a gasket that can exert its effect.

[0005]

In order to achieve the above object, a gasket according to claim 1 of the present invention is a flat body having an inner peripheral edge with a seal portion for generating a surface pressure when sandwiched by a mounting member. Overhangs on the outer peripheral edge of the
Is provided on the outer end surface of the projecting convex portion and has a substantially semicircular cutout in a plane.
A bolt insertion part having a shape is provided, and the bolt insertion part is
Approximately half of the perfect circle that is the cross-sectional shape of the connecting bolt
One that fits approximately concentrically within the semicircle that is the planar shape of the insertion part
And the radius dimension of the former perfect circle and the radius dimension of the latter semi-circle.
We have decided that and are set to be approximately equal to each other .

According to a second aspect of the present invention, a gasket having a substantially semi-circular plane is formed on the outer peripheral edge of a flat plate-shaped main body having an inner peripheral edge with a seal portion for generating surface pressure when sandwiched by a mounting member. The second gasket element having a first gasket element having a required number of bolt insertion portions exhibiting the above is connected to the first gasket element and having a material thickness smaller than that of the first gasket element.

Like the gasket according to claim 1 of the present invention having the above-mentioned structure, the convex portion is projected to the outer peripheral edge of the planar main body having the inner peripheral edge with the seal portion for generating the surface pressure when sandwiched between the mounting members. Part is provided outward in the radial direction, and the projecting convex
Insertion of a bolt in the shape of a semicircular flat surface on the outer end surface of the part
And the bolt insertion portion is a cross-sectional shape of the connecting bolt.
Approximately half of the perfect circle is the plane shape of the bolt insertion part.
It is intended to fit in a semi-circle that is approximately concentric.
The radius dimension and the radius dimension of the latter semicircle are set to be approximately equal to each other.
If defined, in comparison with the above-mentioned conventional technology, the planar shape of the bolt insertion portion is halved from a circle to a semicircle, and accordingly, an outer shape that connects the bolt insertion portions that have a substantially semicircular cutout shape to each other. The outer shape of the planar body defined by the line is planarly downsized. Therefore, by this amount, the dispersion of the tightening load at the time of mounting is suppressed, and the surface pressure of the seal portion is increased.

In addition to this, when a second gasket element having a material thickness smaller than that of the first gasket element is connected to the first gasket element as in the gasket according to claim 2 of the present invention having the above-mentioned structure. As compared with the case where the material thickness of the second gasket element is the same as the material thickness of the first gasket element, the dispersion of the tightening load at the time of mounting is suppressed and the surface pressure of the seal portion is increased. Become.

[0009]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Next, embodiments of the present invention will be described with reference to the drawings.

FIG. 1 shows a plan view of a gasket according to this embodiment. This gasket is used as a cylinder head gasket by being sandwiched between a pair of mounting members, a cylinder blot and a cylinder head. is there. Inside the cylinder block and cylinder head, a cylinder chamber and oil passage are provided as an internal space, and these are sealed to prevent combustion gas in the cylinder chamber and oil in the oil passage from leaking to the outside. This is the function of the gasket. The cylinder block and the cylinder head are connected to each other by a required number of connecting bolts, and the gasket is sandwiched between the two at the time of this connection.

The gasket includes a first gasket element (also referred to as a bore surrounding portion) 1 made of a flat plate metal for sealing the outer circumference of the cylinder chamber, and a second gasket element (also made of a flat plate metal) for sealing the outer circumference of the oil passage ( (Also referred to as oil surrounding portion) 11 as separate parts from each other, and both gasket elements 1 and 11 are stacked in layers at respective connecting portions 7 and 17, and are connected by a connecting means 21 such as rivets, welding or adhesion. Connected to each other.

The first gasket element 1 comprises an annular planar body 2 which is sandwiched between the cylinder block and the cylinder head, and which is clamped on the outer periphery of the cylinder chamber. A hole portion (also referred to as a bore portion) 3 having a substantially circular shape in a plane is provided so as to match the plane shape of the chamber.

The inner peripheral edge of the planar main body 2 is formed in a substantially circular shape in a plane, and a seal portion (also referred to as a bore surrounding seal portion, a bore seal or a primary seal portion) 4 is endlessly provided on the inner peripheral edge. The seal portion 4 is formed in a bead shape such as a half bead or a full bead, but in addition to this, for example, the inner peripheral edge of the planar main body 2 may be bent into a substantially U-shaped cross section and a spacer may be sandwiched therein, and the free state The structure is not particularly limited as long as the height in the plate thickness direction (before mounting) is larger than the plate thickness of the planar main body 2 and surface pressure is generated during mounting.

The outer peripheral edge of the planar main body 2 is also basically formed in a substantially circular shape in a plane. In addition, a necessary number (four positions in the figure) of the protruding protrusions 5 are radially outward. The bolt insertion portions 6 each having a notched shape having a substantially semi-circular plane are provided on the outer end surface of the projecting convex portion 5, respectively. This bolt insertion part 6
Is provided for penetrating the connecting bolt 31 that connects the cylinder block and the cylinder head in the thickness direction of the gasket. The cross-sectional shape of the connecting bolt 31 is a perfect circle (a dotted circle). Approximately half will be accommodated in the semicircle which is the plane shape of the bolt insertion portion 6 in a substantially concentric manner. The radius dimension of the former perfect circle and the radius dimension of the latter semicircle are set to be substantially equal to each other.

The second gasket element 11 is provided with a flat plate-like body 12 which is sandwiched between the cylinder block and the cylinder head and which is sandwiched on the outer periphery of the oil flow passage. A hole portion 13 having a substantially oval shape in a plane is provided so as to match the plane shape of the road. The second gasket element 11 is formed of a metal material having a material thickness thinner than that of the first gasket element 1 described above.

The inner peripheral edge of the flat plate-shaped main body 12 is formed into a substantially oval shape in a plane, and a seal portion (also referred to as oil-surrounding seal portion, oil seal or secondary seal portion) 14 is endlessly provided on the inner peripheral edge. There is. The seal portion 14 is the seal portion 4
Similar to the above, it is formed into a bead shape such as a half bead or a full bead.
The inner peripheral edge may be bent into a substantially U-shaped cross section and the spacer may be sandwiched between the two. The structure is not particularly limited as long as it is generated.

The outer peripheral edge of the flat plate-shaped main body 12 is also basically formed into a substantially oval shape in a plane, but in addition, a required number (four positions in the figure) of protruding protrusions 15 are provided at each corner position. The bolt insertion portions 16 that are provided outward are provided at two of the four locations and have a hole shape of a substantially circular shape in a plan view, respectively, and the remaining two locations are the connection portions 17 described above. ing.

The gasket having the above structure is used as a cylinder head gasket sandwiched between the cylinder block and the cylinder head as described above, and is characterized by the following effects. is doing.

That is, first of all, looking at the first gasket element 1 for sealing the outer periphery of the cylinder chamber, the inside of the seal portion 4 which is sandwiched between the cylinder block and the cylinder head at the time of mounting to generate a surface pressure. Since the bolt insertion portions 6 having a substantially semicircular cutout shape in a plane are provided in four equal distributions on the outer peripheral edge of the annular flat plate-shaped main body 2 provided in the peripheral edge, such a substantially semicircular cutout shape in a plane is formed. The external shape of the first gasket element 1 in which the bolt insertion portions 6 to be presented are provided in an even distribution,
The conventional bolt insertion portion having a substantially circular hole shape in a plane is made smaller in size than the outer shape of the gasket element provided with the same equal number of distributions. Therefore, the plane area of the first gasket element 1 is reduced, the tightening load acting on the gasket during mounting is suppressed from being dispersed, the tightening load is concentrated on the seal portion 4, and the surface pressure generated on the seal portion 4 is increased. Therefore, the sealing property can be improved.

As a comparative example, FIG. 2 is provided with a gasket element 41 in which bolt insertion portions 46 each having a substantially circular planar shape are provided in four equal distributions under the same design conditions as the gasket according to the present embodiment. The planar shape of the gasket is shown. Compared to this comparative example, the gasket has a reduced plane area of about 40%, and the sealability is improved by this amount.

In addition to this, the second gasket element 11 having a material thickness smaller than that of the first gasket element 1 is provided in the first gasket element 1 like the gasket having the above-mentioned configuration.
Is connected, the dispersion of the tightening load at the time of mounting is suppressed as compared with the case where the material thickness of the second gasket element 11 is the same as the material thickness of the first gasket element 1 (see the comparative example above). As a result, the surface pressure of the seal portion 4 is increased, so that a gasket having excellent sealing properties can be provided.

Regarding the laminated structure of the connecting portions 7 and 17 of the first gasket element 1 and the second gasket element 11,
In order that this does not hinder the concentration of the tightening load on the seal portion 4, it is necessary to make the thickness of this laminated structure including the connecting means 21 smaller than that of the seal portion 4.

[0023]

The present invention has the following effects.

That is, first, in the gasket according to the first aspect of the present invention having the above-mentioned structure, the inner peripheral edge is provided with the seal portion which generates the surface pressure when sandwiched by the mounting members such as the cylinder block and the cylinder head. Protruding projections are provided on the outer peripheral edge of the planar main body so as to face outward in the radial direction.
The outer end surface of the projecting protrusion has a notched shape with a substantially semicircular plane.
A bolt insertion part, and the bolt insertion part is
Approximately half of the perfect circle that is the surface shape is the plan shape of the bolt insertion part.
It is to be housed in a semi-circular shape that is almost concentric.
The radius of the perfect circle and the radius of the latter semicircle are almost equal
Because they are properly configured, the outer shape of the gasket bolt insertion portion is provided exhibiting such flat, substantially semicircular notch shape, a conventional bolt insertion portion is provided which exhibits a flat, substantially circular hole shape The size of the gasket is reduced in plan from the outer shape of the gasket. Therefore, the flat area of the gasket is reduced, the tightening load acting on the gasket during mounting is suppressed, the tightening load is concentrated on the seal part, and the surface pressure generated at the seal part is increased, so that the sealing performance is improved. Can be improved. In addition, since the flat area of the gasket is reduced, the amount of material can be reduced, which is advantageous in terms of cost.

In addition to this, in the gasket according to claim 2 of the present invention having the above-mentioned structure, the second gasket element having a material thickness smaller than that of the first gasket element is connected to the first gasket element. As compared with the case where the material thickness of the second gasket element is the same as the material thickness of the first gasket element, the dispersion of the tightening load at the time of mounting is also suppressed and the surface pressure of the seal portion is increased. Therefore, the sealability can be improved by this, and a gasket having excellent sealability can be provided.

[Brief description of drawings]

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

FIG. 2 is a plan view of a gasket according to a comparative example.

FIG. 3 is a plan view of a conventional gasket.

[Explanation of symbols] 1 First gasket element 2,12 flat body 3,13 holes 4,14 Seal part 5,15 Overhanging convex part 6,16 bolt insertion part 7,17 Connection part 11 Second gasket element 21 Connection means 31 Connection bolt

Claims (2)

(57) [Claims] 1. A bulging projection (5) is radially outwardly provided on an outer peripheral edge of a flat body (2) having a seal portion (4) on the inner peripheral edge thereof, which generates a surface pressure when sandwiched by a mounting member. Provided for
A cutout shape of a substantially semicircular plane is formed on the outer end surface of the projecting convex portion (5).
Is provided with a bolt insertion part (6), and the bolt insertion part
(6) is a perfect circle that is the cross-sectional shape of the connecting bolt (31).
Approximately half is a semicircle that is the planar shape of the bolt insertion part (6)
The radius of the former perfect circle is
And the radius of the latter semicircle are set to be approximately equal to each other.
Gasket, characterized in that is. 2. A bolt having a substantially semi-circular planar cutout shape on the outer peripheral edge of a flat plate-shaped main body (2) having a seal portion (4) on the inner peripheral edge thereof, which generates a surface pressure when sandwiched by a mounting member. A second gasket element (11) having a first gasket element (1) provided with a required number of insertion portions (6) and having a material thickness smaller than that of the first gasket element (1) in the first gasket element (1). ) Is connected to the gasket.