JPH0533890A - Pipe joint - Google Patents

Abstract

PURPOSE:To restrict a tightening margin prevented from exceeding a fixed value in a gasket interposed between two pipes to be connected even when tightening torque of a bolt is increased. CONSTITUTION:A gasket 40 is interposed between a swollen part 11 formed in the first pipe 10 and a flare part 21 formed in the second pipe 20, and the first/second pipes 10, 20 are given axial force and fastened by tightening a clamp 30, having a cut 31 in one part in the peripheral direction, by a bolt 50. A tightening margin of the gasket is restricted to a tightening margin of the gasket 40 when a space of the cut 31 is decreased to zero by tightening the bolt 50.

Description

Detailed Description of the Invention

[0001]

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

[0002]

2. Description of the Related Art Conventionally, a pipe joint which fastens a pair of half-divided clamp members with bolts and changes the circumferential clamping force of the clamp members into an axial force by contact with a tapered surface to couple two pipes. However, it is known, for example, from Japanese Utility Model Publication No. 57-73485.

[0003]

However, in the conventional pipe joint of the type which is fastened by the clamp member, the axial force between the two pipes becomes infinitely large if the tightening torque of the bolt is increased. Finally, there is a problem in that the sealing material interposed between the two pipes is damaged, resulting in deterioration of reliability and durability of the sealing property.

An object of the present invention is to provide a pipe joint of a type in which two pipes are fastened by changing a circumferential fastening force by a bolt of a clamp into an axial force, and even if the fastening torque of the bolt is increased, a gap between the two pipes The purpose is to regulate the tightening margin of the gasket that is installed in the cylinder so that it does not exceed a certain value.

[0005]

According to the present invention, the above object can be achieved by the following means. That is, a first pipe having a bulged portion that bulges outward in the radial direction and extends in the circumferential direction at the end, a flare portion that expands in the radial direction, and a first pipe that bends from the flare portion and extends toward the bulged portion. 1
Second pipe having the flange at the end thereof, one cut in the circumferential direction with the second flange, and a bendable portion on the side opposite to the cut, and the portion excluding the cut and bendable portion Has a mountain-shaped cross section so that it can contact the bulging portion and the flare portion from the outer peripheral side, and the tip of the first flange contacts the outer surface of the bulging portion when the second flange abuts. A pipe joint comprising: a clamp having a second flange-to-flange interval set so as to abut, and a gasket interposed between the bulging portion and the flare portion.

[0006]

In the pipe joint of the present invention, when the second gap between the second flanges of the clamp cut becomes zero as the bolt is tightened, the clamp diameter will not be reduced even if the bolt is tightened any more. It also does not increase the axial force of the second pipe. Therefore, no further tightening force is applied to the gasket interposed between the bulge portion and the flare portion, and the gasket is not damaged by over-tightening the bolt.

[0007]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT A preferred embodiment of the present invention will be described below with reference to the drawings. As shown in FIGS. 1 to 5, the pipe joint according to the embodiment of the present invention includes a first pipe 10 and a second pipe 2.
0, clamp 30, gasket 40, and bolt 50
And consists of. The first pipe 10 is an upstream pipe and the second pipe 20 is a downstream pipe.

The first pipe 10 is, as shown in FIG.
The end portion has a bulging portion 11 that is bent in the radial direction and extends over the entire circumference in the bulging circumferential direction. The cross-sectional shape of the bulging portion 11 is a shape formed by two equilateral sides of an isosceles triangle,
A small R is attached to the apex. Bulge 11
A straight portion 12 whose pipe wall extends straight in the axial direction is left on the pipe end side.

The second pipe 20, as shown in FIG.
A flare portion 21 having a radially enlarged diameter is provided at the end portion.
The flare portion 21 is enlarged so that the diameter becomes larger toward the tube end. The flare portion 21 is inclined at the same angle as the portion of the bulging portion 11 of the first pipe 10 facing the flare portion 21.

The second pipe 20, as shown in FIG.
The flare portion 21 has a first flange 22 that is bent at a substantially right angle from the end portion on the pipe end side and that extends short toward the bulging portion 11 side of the first pipe 10. When the tip of the first flange 22 hits the bulging portion 11 of the first pipe 10, the second pipe 20 cannot approach the first pipe 10 in the axial direction any further, and at this time, Pipe 1
A space is created between the bulging part 11 of 0 and the flare part 21 of the second pipe 20, and the gasket 40 is inserted into this space.

A portion of the second pipe 20 following the flare portion 21 is a straight portion 23 having a diameter slightly larger than that of the straight portion 12 of the first pipe 10 over a predetermined distance. Straight part 12 of pipe 10
Is inserted. A straight portion 24 having the same diameter as that of the first pipe 10 is integrally connected to a straight portion 23 of the second pipe 20 having a slightly larger diameter.

The clamp 30 has one cut 3 in the circumferential direction.
It consists of a ring with 1. The clamp 30 has a pair of ends that form a cut and is bent outward in the radial direction to form a pair of second flanges 32, 32. A bendable portion 33 (also shown in FIG. 5) is provided on the side of the annular clamp 30 opposite to the cut 31.
When attaching to the outer circumference of the first and second pipes 10 and 20, the elasticity of the bendable portion 33 is used to expand the clamp 30, and the first and second pipes 10 and 20 are extended through the enlarged cut 31. Is inserted into the clamp 30.

The portion of the clamp 30 excluding the cut 31 with the second flange and the bendable portion 33 is formed in a mountain shape having two equal-length two sides of an isosceles triangle in cross section, and a mountain-shaped cross section 34. Are configured. Clamp 30
The slope of the chevron section is the same as the chevron slope formed by one side of the bulging portion 11 of the first pipe 10 and the flare portion 21 of the second pipe 20. This allows the clamp 3
When 0 is tightened to reduce the diameter, the chevron-shaped section 34 of the clamp 30 has an inner surface on one side on the outer surface of one side of the bulging portion 11 of the first pipe 10 and an inner surface on the other side of the second pipe 20. The outer surface of the flare portion 21 is pressed. By the pressing of the inclined surface, the circumferential tightening force of the clamp 30 is converted into the axial force of the first pipe 10 and the second pipe 20 in the directions toward each other.

A third flange 35 extending in the axial direction of the first and second pipes 10 and 20 is formed on both sides in the width direction of the chevron-shaped portion 34 of the clamp 30. This flange 35 is also formed on the second flange 32. Second
The central portion 36 of the flange 32 other than the flange 35 is offset stepwise from the flange 35 in the direction away from the opposing second flange, as shown in FIG. The rigidity of 32 is increased.

A bolt hole 37 is provided in the second flange 32. The bolt 50 is inserted into the bolt hole 37, and the nut 51 is screwed into the threaded portion of the bolt 50, so that the pair of second flanges 32 approach each other.
Tighten the clamp 30. When the flange 35 of the second flange 32 on one side approaches the flange 35 of the second flange 32 on the other side and abuts each other, even if the torques of the bolt 50 and the nut 51 are further increased. , The diameter of the clamp 30 does not shrink, so
An axial force equal to or greater than the axial force when the second flange 32 abuts does not act on the first and second pipes 10 and 20.

As the bolt 50 is tightened, the clamp 30
The diameter of the first pipe becomes smaller, the first and second pipes 10 and 20 come closer to each other, and finally the second flange 32 of the clamp 30.
Contact each other, but at this time, the interval between the second flanges 32 before bolting is set so that the tip of the first flange 22 of the second pipe 20 contacts the bulging portion 11. There is.

When a circumferential detent between the first pipe 10 and the second pipe 20 is required, the structure shown in FIGS. 6 and 7 may be provided. That is, the straight portion 12 of the first pipe 10 is partially provided with the concave portion 13 in the circumferential direction,
The straight portion 23 of the second pipe 20 is formed with a convex portion 25 that partially protrudes radially inward in the circumferential direction.
Are engaged with the recess 13.

Next, the operation will be described. Regarding the assembly of the pipe joint, first, the second pipe 20 is connected to the first pipe 10.
And the gasket 40 is held between the bulging portion 11 and the flare portion 21, and then the clamp 30 is opened to embrace the bulging portion 11 and the flare portion 21. Clamp 3 around the second pipe 20
0 is attached, and then the clamp 30 is tightened by the bolt 50 and the nut 51 to tighten the first and second pipes 10 and 20 in the axial direction.

When the bolts 50 are tightened and finally the distance between the second flanges 32 of the clamp 30 becomes zero and the second flanges 32 come into contact with each other, the clamp 3 is further pushed.
The diameter of 0 does not shrink, so beyond that the first, second
The axial force of the pipes 10 and 20 does not increase. As a result, the gasket 4 inserted between the bulging portion 11 and the flare portion 21
0 does not require a tightening margin greater than the gasket tightening margin when the second flanges 32 come into contact with each other.
The reliability and durability are improved. In addition, the axial force regulation of the first and second pipes 10 and 20 is not limited to the gasket 40, but the bulge portion 11, the flare portion 21, and the first flange portion 22.
To prevent deformation.

A first flange 22 is provided at the tip of the flare portion 21 so that the tip of the first flange 22 just contacts the bulging portion 11 when the second flanges 32 come into contact with each other. Since the shape and dimension are set to, the upper limit of the tightening margin of the gasket 40 is also regulated by the gasket tightening margin when the second flanges 32 come into contact with each other. Therefore, it is doubly regulated.

In this case, if the second flange 32 is restricted by the first flange 22 alone, not by the contact between the second flanges 32, the first flange 22 and the second flange 32 expand when tightened. Although fretting may occur at the contact portion of the protruding portion 11 and damage to the bulging portion 11, the first flange 22 just contacts the bulging portion 11 when the second flanges 32 come into contact with each other. Therefore, the first flange 22 and the bulge 1 are further extended.
Since no load is applied to the contact portion of No. 1, damage due to fretting does not occur.

In the pipe joint assembled as described above, the maximum tightening margin of the gasket 40 is regulated, the gasket 40 is not directly exposed to high-temperature exhaust gas, and the first pipe 10 and the second pipe 10 are Since the pipe 20 is also prevented from rotating in the circumferential direction and the gasket 40 is not rubbed in the circumferential direction, the gasket 40 has high reliability and durability.

[0023]

According to the present invention, even if the tightening torque of the bolt is increased, the tightening margin of the gasket interposed between the bulging part and the flare part is brought into contact with the second flange of the clamp. Since it is possible to regulate the gasket tightening allowance at that time, the reliability and durability of the sealing performance of the pipe joint can be greatly improved.

[Brief description of drawings]

FIG. 1 is a longitudinal sectional view of a clamp of a pipe joint according to an embodiment of the present invention.

FIG. 2 is a front view of the clamp of FIG.

FIG. 3 is a plan view of the clamp of FIG.

FIG. 4 is a perspective view of the vicinity of a second flange portion of the clamp shown in FIG.

5 is a perspective view near the bendable portion of the clamp of FIG. 2. FIG.

6 is a cross-sectional view taken along the line AA of the pipe joint of FIG.

7 is a cross-sectional view of the first pipe taken along the line BB of the pipe joint of FIG.

[Explanation of reference numerals] 10 first pipe 11 bulging portion 12 straight portion 13 concave portion 20 second pipe 21 flare portion 22 first flange 23 straight portion 24 straight portion 25 convex portion 30 clamp 31 break 32 second flange 33 bendable part 34 chevron shaped section 35 flange 36 central part of the second flange 37 bolt hole 40 gasket 50 bolt 51 nut

Claims (1)

Claim: What is claimed is: 1. A first pipe having a bulged portion that bulges outward in the radial direction and extends in the circumferential direction at the end, a flare portion that is expanded in the radial direction, and bends from the flare portion. A second pipe having at its end a first flange extending toward the bulging portion, a circumferentially extending slit with a second flange, and a bendable portion on the side opposite to the slit; The cross-sectional shape of the portion excluding the cut and the bendable portion is formed into a mountain shape so that the bulging portion and the flare portion can be contacted from the outer peripheral side, and the first flange when the second flange abuts A clamp in which a second inter-flange space is set so that the tip of the bulge contacts the outer surface of the bulging portion, and a gasket interposed between the bulging portion and the flare portion. Pipe fittings.