JPH0647772U - Metal gasket - Google Patents

Abstract

(57) [Summary] [Structure] A metal gasket that is inserted between joint surfaces and fastened with bolts, and a cross section of the bead 3 having a chevron convex shape is taken from the center direction of the entire joint surface with the bead center line C as a boundary. One side is an arcuate portion 3a, one side from the bolt fastening portion P has a width larger than the width of the arcuate portion 3a, and the arcuate portion 3a is
A linear portion 3b that is inclined from a in a substantially linear shape and is continuous with the flat surface portion 3c is formed, and the linear portion 3b is formed wider as it gets closer to the bolt fastening portion P, and between the bolt fastening portions P and P. The width of only the linear portion 3b was changed according to the change in surface pressure. [Effect] Not only the deflection between the bolt fastening portions P, but also the deflection that changes as the distance from the bolt fastening portion P increases in the direction of the center F of the entire joint surface, a uniform bead surface pressure can be applied at the same time. it can. In addition, it becomes possible to easily tighten the bolts and prevent loosening of the tightened bolts as much as possible.

Description

[Detailed description of the device]

[0001]

[Industrial applications]

 The present invention relates to a metal gasket which is inserted into a joint surface of an internal combustion engine or the like and fastened with bolts to improve the seal performance of the joint surface.

[0002]

[Prior art]

 Conventionally, a metal gasket is inserted on the joint surface of an internal combustion engine or the like, and the bead formed at the place where the metal gasket should be sealed is elastically deformed by the bolt tightening force when the joint surface is fastened, and by the elastic restoring force at this deformation. By forming an elastic seal line on the joint surface, the bead follows the strain of the joint surface and seals.

However, the actual bending of the joint surface at the time of bolt fastening is not only between the joint surfaces of the bolt fastening portions, but also when the clearance of the joint surface is widened from the bolt fastening portion toward the center of the joint surface. It causes deformation.

Various techniques have been conventionally proposed to cope with the deformation of the joint surface when the bolt is fastened. For example, in the metal gasket described in Japanese Patent Publication No. 62-261755, a bead is formed so as to increase the bead pressure by paying attention to the surface pressure of the joint surface which decreases as the distance from the bolt fastening portion increases. , This bead is a step-shaped bead, and it is not possible to deal with the deformation that gradually widens the gap of the joint surface (increases the surface pressure) as it is separated from the bolt fastening part in the center direction of the joint surface. is there. That is, the bead pressure can be changed in each part along the seal part, but the bead height and the bead pressure gradually increase in the part from the bolt fastening part toward the center of the entire joint surface. It is impossible to make it happen.

The metal gasket disclosed in Japanese Utility Model Publication No. 63-42202 is made in view of the phenomenon that the gap between the joint surfaces widens and the bead pressure decreases as the distance from the bolt fastening portion increases. It was bilaterally symmetric, and the bead height and the bead pressure could not be gradually increased in a portion that goes from the bolt fastening part toward the center of the entire joint surface as described above.

[0006]

[Problems to be solved by the device]

 The object of the present invention will be described with reference to the drawings. In FIGS. 1 (a) to 1 (c), when bolts 5 are fastened to the mating joint surface 2 at required locations on the periphery of the joint surface 1, they are directed toward the center F direction of the joint surface 1 as they are separated from the bolt fastening portion P. And deform so as to widen the gap between the joint surfaces. The widening condition is shown in FIG. 1 (b) for the section taken along line H-H in FIG. 1 (a), and in FIG. 1 (c) for the section taken along line I-I in FIG. 1 (a). .

[0007] Now, when a conventional metal gasket having a bead with a constant load is inserted between the deformed joint surfaces, a strong bead pressure is generated in the vicinity of the bolt fastening portion P and the bolt 5 is tightened. As a result, the clearance increases as the bolt fastening portion P approaches the center F, and as a result, the amount of deflection of the bead cannot be adapted to this and the sealing pressure is reduced, causing gas leakage. It was.

The present invention has been made in view of the above circumstances. When the joint surface is fastened to a main part of the periphery of the mating joint surface with a bolt, the joint surface whole is separated from each bolt fastening portion. To cope with the phenomenon that the gap between the joint surfaces is widened toward the center of the joint and the surface pressure between the joint surfaces is gradually reduced, without changing the bolt fastening force, the seal part between the joint surfaces is not changed. It is an object of the present invention to provide a metal gasket capable of improving the sealing property by balancing the bead pressure distribution of the same and at the same time preventing loosening of fastening bolts.

[0009]

[Means for Solving the Problems]

 In order to solve the above-mentioned problems, the metal gasket of the present invention is formed by forming a mountain-shaped convex bead on a metal plate or a plate material obtained by applying a sealing material to a metal plate, and inserting it between the joint surfaces to fasten it with a bolt. In the metal gasket forming the seal, the gap between the joint surfaces increases due to the deflection as the distance from the bolt fastening portion toward the center of the joint surface increases, and the surface pressure change correspondingly decreases in accordance with the change in the contact pressure. The bead cross section has an arc shape on one side from the center direction of the entire joint surface with the bead center line as a boundary, and one side from the bolt fastening part has a width larger than the width of the arc shape part, and A shape that is continuous from the arc-shaped portion into a substantially linear shape and that is continuous with the flat surface portion, and that the linear-shaped portion is formed wider as it approaches the bolt fastening portion, and the space between the bolt fastening portions is The width of the linear portion only is obtained is changed according to the surface pressure changes.

[0010]

[Action]

 The metal gasket G having the above-mentioned configuration is inserted between the joint surface 1 and the mating joint surface 2 as shown in FIG. 1 (b) or (c), and fastens the peripheral portion with a plurality of bolts 5. Is. The cross-sectional shape of the mountain-shaped convex bead 3 formed on the metal gasket G will be described with reference to FIG. 2 (c). One side of the joint surface 1 of the bead center line C in the direction of the center F has an arc shape, and the arc shape part The other side of 3a has a width L2 (L1 <L2) larger than the width L1 of the arc-shaped portion 3a, and the bead height of the arc-shaped portion 3a is inclined substantially linearly from the arc-shaped portion 3a. The bead height H2 (H1> H2) lower than H1 is formed so as to be continuous with the flat surface portion 3c. However, the linear portion 3b is formed wider as it gets closer to the bolt fastening portion P 1, and the width of only the linear portion 3b between the bolt fastening portions P 1 and P 2 is changed according to the surface pressure change.

Therefore, when this metal gasket G is inserted between the joint surface 1 and the mating joint surface 2 and the required portions are fastened with the bolts 5, the weak bead pressure F3 is close to the linear portion 3b close to the bolt fastening portion P. And the bead height H2 is low, the bead pressure F2 (F3 <F2) is stronger in the arc-shaped portion 3a, and the bead height H1 (H2 <H1) is higher, resulting in the bolt fastening force. Is constant, the bead pressure distribution can be balanced even between the joint surfaces extending from the bolt fastening portion P toward the center F of the joint surface 1 to improve the sealing performance.

[0012]

Embodiments Embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 (a) is a plan view for explaining a plane condition of the metal gasket of the present invention, and FIG. 1 (b) is a sectional view taken along line H-H of FIG. 1 (a) when bolts are fastened. FIG. 1 (c) is a diagram showing the widening state between the joint surfaces, and FIG. 1 (c) is a diagram showing the widening state between the joint surfaces when bolting the cross-section along the line II of FIG. 1 (a). Fig. 2 (a) is a graph showing the surface pressure of the joint surface along the line AA in Fig. 1 (a), and Fig. 2 (b) shows the gap width of the joint surface at the location corresponding to Fig. 2 (a). Fig. 2 (c) is a graph showing the cross-sectional situation of the bead formed corresponding to the surface pressure and the gap width shown in Fig. 2 (a) and Fig. 2 (b). Corresponding to the bead cross section taken along the line AA, FIG. 2 (d) is a view showing the cross-sectional state of the bead taken along the line D-D in FIG. 1 (a), and FIG. 2 (e) is a diagram. It is a figure which shows the cross-sectional condition of the bead which follows the EE line of 1 (a). 3 (a) is a sectional view taken along the line AA of FIG. 1 (a), and FIG. 3 (b) is a sectional view taken along the line EE of FIG. 1 (a).

The metal gasket G of the present invention is one in which a chevron-shaped bead 3 is formed along a sealing portion between the joint surface 1 and the mating joint surface 2 on a metal plate or a metal plate coated with a sealant. Is. That is, one side from the center F direction of the joining surface 1 with the bead centerline C as a boundary is formed into an arc shape drawn with a radius centered on a fixed point on the bead centerline C, and this one side bead is an arc. The shape portion 3a has a width L2 larger than the width L1 of the arc-shaped portion 3a on one side of the bead centerline C as a boundary, and is inclined substantially linearly from the arc-shaped portion 3a. With a bead height H2 that is lower than the bead height H1 of the arc-shaped portion, the bead height H2 is continuous with the flat surface portion 3c, and the bead on one side is a linear portion 3b.

The bead shape as described above is formed in the cross section along the line AA in FIG. 1A, that is, between the joining surfaces extending from the vicinity of the bolt fastening portion P toward the center F of the entire joining surface 1. The specific cross-sectional situation is shown in Figure 3 (a).

However, the metal gasket G of the present invention has such an asymmetrical bead cross-sectional shape at the portion extending from the vicinity of the bolt fastening portion P toward the center F of the entire joint surface 1 as described above. Therefore, as shown in FIGS. 2 (d) to 2 (e), the width of only the linear portion 3b is changed to L2> L3> L1 between the bolt fastening portions P and P according to the change of the surface pressure. Since the bead pressure is increased by increasing the load on the bead 3 as a whole, the bead deflection amount with respect to a certain bolt fastening force is reduced as the distance from the bolt fastening portion P is increased. The gaps are filled evenly. Therefore, at the intermediate position between the bolt fastening portions P, P, that is, at the EE line cross section of FIG. 1, the widths of the arc-shaped portion 3a and the straight-shaped portion 3b may have the same left-right symmetrical shape (L1 = L1). Of. A specific cross-sectional shape of the intermediate position between the bolt fastening portions P and P is shown in FIG. 3b.

In the method of forming the bead 3 as described above, when the required portion of the peripheral portion of the joint surface 1 is fastened to the mating joint surface 2 with the plurality of bolts 5, the method shown in FIGS. By adjusting the bead height H1 and width L1 of the arc-shaped portion 3a and the bead height H2 and width L2 of the straight-shaped portion 3b by obtaining the measurement results of the contact surface pressure and the clearance as shown in b). Between the bolt fastening portions P, P, the width of only the linear portion 3b is formed from L2 to L1 which is narrower than L2 in accordance with the above-mentioned surface pressure and gap change.

[0018]

[Effect of device]

 As described above, the bending phenomenon of the joint surface that occurs when the required portion of the peripheral portion of the joint surface is fastened to the mating joint surface by the conventional technique is applied to the change in the deflection between the bolt fastening portions. However, it was possible to deal with it, but it was not possible to deal with the flexural change that changes as the distance from the bolt fastening portion toward the center of the entire joint surface increases.

According to the present invention, not only the deflection between the bolt fastening portions but also the deflection that changes with the distance from the bolt fastening portion toward the center of the entire joint surface is applied with a uniform bead surface pressure at the same time. As a result, it is possible to balance the bead pressure distribution on the joint surface and improve the sealing performance.

Further, in the present invention, the bead shape in the vicinity of the bolt fastening portion is received by the one straight side portion having a relatively low bead height and surface pressure, so that the bolt fastening can be performed easily. In addition, it becomes possible to prevent loosening of the tightened bolts as much as possible.

[Brief description of drawings]

[0021]

FIG. 1 (a) is a plan view for explaining a plane condition of a metal gasket of the present invention, and FIG. 1 (b) is a H-H of FIG. 1 (a).
Fig. 1 is a diagram showing the widening state between the joint surfaces when the bolts of the cross section along the line are fastened. Fig. 1 (c) is the widening between the joint surfaces when the bolt is fastened of the cross section along the line I-I of Fig. 1 (a). It is a figure which shows a situation.

[0022]

FIG. 2 is a diagram for explaining the method for forming a metal gasket of the present invention, FIG. 2 (a) is a graph showing the surface pressure along the line AA of FIG. 1 (a), and FIG. 2 (b) is a graph showing the gap width of the joint surface at the location corresponding to FIG. 2 (a), and FIG. 2 (c) is shown in FIG.
It is a figure which shows the cross-sectional condition of the bead formed corresponding to the surface pressure and gap width shown to (a) and FIG. 2 (b), and A of FIG. 1 (a).
It corresponds to the bead cross section along the line A, and Fig. 2 (d) is shown in Fig. 1 (a).
2 is a view showing a bead cross-sectional situation along the line D-D of FIG.
(e) is a figure which shows the cross-sectional condition of the bead along the EE line of Fig.1 (a).

[0023]

3 (a) is a sectional view taken along the line AA of FIG. 1 (a), and FIG. 3 (b) is a sectional view taken along the line EE of FIG. 1 (a).

[0024]

[Explanation of sign]

DESCRIPTION OF SYMBOLS 1 ... Joining surface, 2 ... Opposite joining surface, 3 ... Bead, 3a ... One side arc shape part of bead, 3b ... One side linear shape part of bead,
3c ... Plane part, 5 ... Fastening bolt, P ... Bolt fastening part.

Claims (1)

[Scope of utility model registration request] 1. A metal gasket in which a chevron-shaped bead is formed on a metal plate or a plate material obtained by applying a sealing material to a metal plate, and the bead is fastened by inserting it between joint surfaces to fasten it with a bolt. The bead cross-section of the chevron-shaped convex shape according to the gap between the joint surfaces that increases due to the deflection as the distance from the joint surface increases toward the center of the joint surface and the surface pressure change that decreases accordingly. One side from the center direction of the entire surface has an arc shape, one side from the bolt fastening part has a width larger than the width of the arc shape part, and the flat part is inclined from the arc shape part in a substantially linear shape. A continuous shape, and further, the linear shape portion is formed wider as it gets closer to the bolt fastening portion,
The metal gasket is characterized in that the width of only the linear portion between the bolt fastening portions is changed according to the change in surface pressure.