JP2002235880A - Insertion joint - Google Patents

Abstract

PROBLEM TO BE SOLVED: To hold a stable seal function with a low cost, and prevent degradation for a long period. SOLUTION: At an end portion of a first pipe 1, an angle bead 2 is formed to expand to diametrically outward. At an end portion of a second pipe 5, a flare 6 is formed to open diametrically outward. An outer peripheral edge of the flare is bent inward to closely contact with an inclination surface 7 to form a flat ring 8. On an inner side of the flat ring, a ring gasket 10 is placed, and the bead and the flare are fitted in with a clamp 12 having an angle cross-section. Thus, a flat ring 8 of the flare is pressed to contact with the inclination surface 3 of the bead, thereby connecting the first pipe and the second pipe. The height of the flat ring is uniform on the whole periphery. The gasket is compressed only to the height of the flat ring, so that a restoring force by elasticity is held, and sealing function is held for a long period.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a structure of a bayonet joint used for connecting, for example, an exhaust pipe of a vehicle.

[0002]

2. Description of the Related Art An example of a conventional joint of this type is shown in FIG. In the joint shown in FIG. 3A, the first pipe 1 and the second pipe 20 to be connected to each other have the first pipe 1
The second pipe 20 forms a radially outwardly expanding flare 21 at its end, and forms a radially outwardly expanding flare 21 at the end of the second pipe 20. The first pipe 1 is inserted. Then, the first pipe 1 is placed on the inclined surface 22 of the flare 21 of the second pipe 20.
With the gasket 25 interposed therebetween, and the bead 2 is clamped by the clamp 12 having a mountain-shaped cross section.
And flare 21. The two pipes 1 and 20 are connected by the tightening by the clamp 12, and the gasket 25 is compressed so that the inclined surface 22 of the flare 21 and the inclined surface 3 of the bead 2 are hermetically sealed.

[0003]

However, in the above-described joint structure, the gasket 25 between the flare 21 and the bead 2 tightened by the clamp 12 is strongly compressed, and furthermore, the exhaust gas flowing through the pipe is affected by the high temperature for a long time. Loses resilience. For this reason, as a result of the displacement between the first pipe 1 and the second pipe 20 due to vibration during driving of the vehicle, the sealing function is reduced, and
Gasket 25 after disconnection for pipe repair
Will not withstand reuse.

As a countermeasure, for example, Japanese Patent Laid-Open No. 5-33890
In order to prevent the gasket between the flare and the bead from being compressed indefinitely, as shown in FIG. 3B, the outer peripheral edge of the flare 21 'faces the inclined surface 3 of the bead 2 in order to prevent the gasket between the flare and the bead. It has been proposed to form the flange 23 by pressing. According to this, the edge of the flange 23 comes into contact with the inclined surface 3 of the bead 2, and the gasket 25 is not compressed to be thinner than the height of the flange 23.

[0005] However, it is not easy to obtain accuracy in the flange processing of the outer peripheral edge of the flare 21 '. The height of the flange 23 formed on the outer peripheral edge varies depending on the location, and the edge itself is also flanged. The fact is that you lose the smoothness in the event. For this reason, it is not possible to secure a uniform connection state as designed between the inclined surface 22 of the flare 21 ′ and the inclined surface 3 of the bead 2 over the entire circumference. Further, if the end portion is modified to keep the height of the flange 23 constant after the flange processing, the production cost is increased. Accordingly, an object of the present invention is to provide a bayonet joint that can maintain a stable sealing function at low cost without causing deterioration over a long period of time in view of the above problems.

[0006]

According to the present invention, a first pipe having a mountain-shaped bead bulging radially outward at an end thereof is provided at an end thereof radially outward. It is inserted into the second pipe having the expanding flare, and tightened with a clamp from the outside in a state where the inclined surface of the bead and the inclined surface of the flare face each other to connect the first pipe and the second pipe. In the plug-in joint, a flat flat ring is provided on the outer peripheral portion of the inclined surface of the flare, and a ring-shaped gasket is arranged inside the flat ring between the inclined surface of the bead and the inclined surface of the flare. Thus, in the connected state, the thickness of the gasket is limited to the plate pressure of the flat ring.

[0007] Since the compression amount of the gasket is limited by the plate pressure of the flat ring, the restoring force due to the elasticity of the gasket is maintained, and even if the first pipe and the second pipe are repeatedly displaced by vibration or the like, the sealing is performed. The function is not reduced, and reuse after disconnection is possible.

In the invention of claim 2, the flat ring is formed by bending the outer peripheral edge of the flare inward. As a result, a flat ring with a constant plate pressure is realized on the outer peripheral portion of the inclined surface of the flare in a simple process.

[0009]

Embodiments of the present invention will be described below. FIG. 1 is a cross-sectional view showing an embodiment, in which a first pipe 1 and a second pipe 5 connected to each other are shown separated from each other. The first pipe 1 is formed at its end with a mountain-shaped bead 2 bulging radially outward, and is the same as the conventional one shown in FIG.

The second pipe 5 is formed at its end with a flare 6 expanding radially outward. The outer peripheral edge of the flare 6 is folded inward, that is, toward the side of the inclined surface 7 facing the bead 2 of the first pipe 1, and closely overlaps the inclined surface 7. As a result, the folded portion forms a flat ring 8 having a small width and the same height as the plate pressure of the flare 6 on the outer periphery of the inclined surface 7 of the second pipe. A ring-shaped gasket 10 is arranged on the inclined surface 7 of the flare 6 at an inner diameter of the flat ring 8 having the folded portion. The plate pressure of the gasket 10 in the free state is larger than the height of the flat ring 8.

At the time of connection, as shown in FIG.
The first pipe 1 is inserted into the pipe 5 of the second pipe 5 and the bead 2 of the first pipe 1 is placed on the inclined surface 7 of the flare 6 of the second pipe 5.
The bead 2 and the flare 6 are tightened with the clamp 12 having a mountain-shaped cross section with the inclined surfaces 3 facing each other. Thereby, the flat ring 8 of the flare 6 is pressed against the inclined surface 3 of the bead 2,
The first pipe 1 and the second pipe 5 are connected, and the gasket 10 is compressed to the level of the flat ring 8 to seal.

The embodiment is configured as described above, and the amount of compression of the gasket 10 is limited by forming the flat ring 8 by turning the outer peripheral edge of the flare 6.
The restoring force due to the elasticity of the gasket 10 is maintained, and even if the first pipe 1 and the second pipe 5 are repeatedly displaced due to vibration or the like, the sealing function does not decrease. Use is also possible.

Further, since the flat ring 8 is formed by folding the outer peripheral edge of the flare 6, the height thereof is constant with high precision (= flare plate pressure) over the entire circumference. In this case, the connected state as designed is obtained, and the compressed state of the gasket 10 becomes uniform over the entire circumference, so that a more reliable and stable sealing function can be obtained in this regard. It should be noted that even if the width of the flat ring 8 slightly fluctuates in the circumferential direction, the gasket 10 is disposed on the inner diameter side of the flat ring 8 and has no influence.

[0014]

As described above, the present invention relates to a plug-in joint in which the inclined surface of the bead of the first pipe and the inclined surface of the flare of the second pipe are opposed to each other and tightened with a clamp. The flat gasket is placed on top of the flat ring, and the thickness of the gasket placed inside the flat ring is limited to the flat ring pressure. This has the effect that deterioration does not occur for a long period of time even in an environment where it is subjected to, and a stable sealing function can be maintained.

Further, since the flat ring is formed by folding the outer peripheral edge of the flare inward, it can be realized in a simple process at a low cost, and the plate pressure is uniform over the entire circumference and is in close contact with the inclined surface of the flare. As a result, the connection state as set can be obtained, and the compression state of the gasket is also uniform over the entire circumference, so that a more reliable and stable sealing function can be obtained.

[Brief description of the drawings]

FIG. 1 is a diagram showing an embodiment of the present invention.

FIG. 2 is a diagram showing a connection state in the embodiment.

FIG. 3 is a diagram showing a conventional example.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 1st pipe 2 Bead 3 Inclined surface 5 2nd pipe 6 Flare 7 Inclined surface 8 Flat ring 10 Gasket 12 Clamp

Claims (2)

[Claims] 1. A first pipe (1) having a mountain-shaped bead (2) bulging radially outward at an end portion, and a flare (6) expanding radially outward at an end portion. The bead is inserted into the second pipe (5), and the beaded inclined surface (3) and the flare inclined surface (7) are opposed to each other. In the bayonet joint for connecting the second pipe, a flat ring (8) having a plate shape is provided so as to overlap on an outer peripheral portion of the inclined surface of the flare, and between the inclined surface of the bead and the inclined surface of the flare. A bayonet joint, wherein a ring-shaped gasket (10) is disposed inside the flat ring, and a thickness of the gasket is limited to a plate pressure of the flat ring in a connected state. 2. The bayonet joint according to claim 1, wherein the flat ring is formed by folding an outer peripheral edge of the flare inward.