JP3077287B2 - Pipe fittings - Google Patents

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, in a joint of a vehicle exhaust pipe.

[0002]

2. Description of the Related Art Conventionally, a pipe joint for connecting two pipes by tightening a pair of half-split clamp members with bolts, and changing the circumferential tightening force of the clamp members into an axial force by taper surface contact. Is known, for example, from Japanese Utility Model Laid-Open No. 57-73485.

[0003]

However, in a conventional pipe joint which is fastened by a clamp member, the axial force between the two pipes increases without limit if the tightening torque of the bolt is increased. Eventually, there is a problem that the sealing material interposed between the two pipes is broken, and the reliability and durability of the sealing are reduced.

SUMMARY OF THE INVENTION It is an object of the present invention 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, even if the tightening torque of the bolts increases. The purpose of the present invention is to regulate the interference of the gasket interposed in the vehicle so as not to exceed a certain value.

[0005]

According to the present invention, the above object is attained by the following means. That is, the first having a bulging portion extending bulges radially outward circumferential direction on the end pipe, a flare portion which is expanded in a radial direction, and the bulging bent from the <br/> flared portion destination extends towards the part
When the end hits the bulge, the bulge and the flare
A second pipe having a first flange formed at the end , which forms a space with a regulated thickness between the portions, and has a cut with one second flange in the circumferential direction and can be bent to the opposite side to the cut. Having a portion, the cross-sectional shape of the portion excluding the cut and the bendable portion is formed into a chevron shape so that it can contact the bulging portion and the flare portion from the outer peripheral side, and when the second flange abuts A clamp having an interval between the second flanges set so that a tip of the first flange is in contact with an outer surface of the bulging portion, and a clamp formed between the bulging portion and the flare portion.
A gasket inserted into said space .

[0006]

In the pipe joint of the present invention, the existence of the first flange is eliminated.
The thickness of the space between the bulge and flare,
Therefore, the gasket interference is regulated. Further, when the bolts are tightened and the interval between the second flanges at the break of the clamp becomes zero, even if the bolts are further tightened, the diameter of the clamp does not decrease, and thus the axial force of the first and second pipes is also reduced. Not increase. Therefore, even the gasket being interposed between the bulging portion and the flare portion, a take it with more clamping force
No. Gasket interference limit by first flange and second
Gasket overtightening due to zero flange spacing
The double regulation ensures that the gasket will not be damaged by over-tightening .

[0007]

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

As shown in FIG. 1, the first pipe 10
The end has a bulging portion 11 which is bent in the radial direction and bulges and extends over the entire circumference in the circumferential direction. The cross-sectional shape of the bulging portion 11 has a shape formed by two equal sides of an isosceles triangle,
A small R is attached to the apex. Bulge 11
A straight portion 12 in which the pipe wall extends straight in the axial direction is left on the pipe end side.

The second pipe 20, as shown in FIG.
At the end, there is a radially expanded flared portion 21.
The diameter of the flare portion 21 is increased such that the diameter increases as it approaches the pipe 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 is, as shown in FIG.
The flare portion 21 has a first flange 22 which is bent at a substantially right angle from the end of the tube end and extends short toward the bulging portion 11 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 more. Pipe 1
A space is formed between the bulged portion 11 of the second pipe 20 and the flare portion 21 of the second pipe 20, and the gasket 40 is inserted into this space.

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

The clamp 30 is provided with one cut 3 in the circumferential direction.
Consisting of a ring having 1; In the clamp 30, a pair of ends forming a cut is bent radially outward 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.
Is attached to the outer periphery of the first and second pipes 10 and 20, the clamp 30 is expanded by utilizing the elasticity of the bendable portion 33, and the first and second pipes 10 and 20 are expanded through the enlarged cut 31. Is inserted into the clamp 30.

The portion of the clamp 30 excluding the second flanged cut 31 and the bendable portion 33 is formed in a chevron shape having two substantially equal sides of a substantially isosceles triangle, and a cross-sectional chevron portion 34. Is composed. Clamp 30
The slope of the mountain-shaped section is the same as the slope of the mountain shape formed by one side of the bulging portion 11 of the first pipe 10 and the flare portion 21 of the second pipe 20. Thereby, the clamp 3
0 is tightened and the diameter is reduced, the angled section 34 of the clamp 30 is attached to the outer surface of one side of the bulging portion 11 of the first pipe 10 on the inner surface of one side and to the second pipe 20 on the inner surface of the other side. Is pressed against the outer surface of the flare portion 21. By the pressing of the inclined surface, the circumferential tightening force of the clamp 30 is converted into an axial force of the first pipe 10 and the second pipe 20 in a direction approaching 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 angled section 34 of the clamp 30. This flange 35 is also formed on the second flange 32. Second
As shown in FIG. 4, a central portion 36 of the flange 32 other than the flange 35 is offset stepwise from the flange 35 in a direction away from the opposing second flange. 32 has been increased in rigidity.

A bolt hole 37 is provided in the second flange 32. A 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 one second flange 32 approaches the flange 35 of the other second flange 32 opposed thereto and abuts against each other, even if the torque of the bolt 50 and the nut 51 is further increased, , The diameter of the clamp 30 does not shrink,
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
Becomes smaller, the first and second pipes 10 and 20 approach each other, and finally the second flange 32 of the clamp 30.
Are in contact with each other, but the interval before bolt tightening of the second flanges 32 is set so that the tip of the first flange 22 of the second pipe 20 abuts on the bulging portion 11 at this time. I have.

If it is necessary to provide a circumferential stop between the first pipe 10 and the second pipe 20, the structure shown in FIGS. 6 and 7 may be provided. That is, the concave portion 13 is partially provided in the straight portion 12 of the first pipe 10 in the circumferential direction,
A convex portion 25 is formed on the straight portion 23 of the second pipe 20 so as to partially project inward in the radial direction in the circumferential direction.
Is engaged with the recess 13.

Next, the operation will be described. Regarding the assembly of the pipe joint, first, the first pipe 10 is connected to the second pipe 20.
And the gasket 40 is held between the bulging portion 11 and the flare portion 21. Then, the first pipe 10 is connected to the first pipe 10 so that the clamp 30 is expanded to embrace the bulging portion 11 and the flare portion 21. Clamp 3 around the second pipe 20
Then, the clamp 30 is tightened with the bolt 50 and the nut 51, and the first and second pipes 10 and 20 are tightened in the axial direction.

When the bolt 50 is tightened and the interval between the second flanges 32 of the clamp 30 finally becomes zero and the second flanges 32 come into contact with each other, the clamp 3 is further moved.
The diameter of 0 does not shrink, so that the first and 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
In the case of 0, the gasket 40 does not have a tightening allowance greater than the gasket allowance when the second flanges 32 come into contact with each other.
Reliability and durability are improved. The axial force of the first and second pipes 10 and 20 is regulated not only by the gasket 40 but also by the bulging portion 11, the flare portion 21, and the first flange portion 22.
To prevent deformation of the wire.

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. Therefore, the upper limit of the interference of the gasket 40 is also restricted by the gasket interference when the second flanges 32 come into contact with each other. Therefore, it is doubly regulated.

In this case, if the restriction by the first flange 22 alone is used instead of the restriction by the contact of the second flanges 32, when the bolt 50 is tightened, the first flange 22 expands with the first flange 22. There is a possibility that the bulging portion 11 may be damaged due to fretting at the contact portion of the bulging portion 11, but when the second flanges 32 come into contact with each other, the first flange 22 just contacts the bulging portion 11. The first flange 22 and the bulge 1
Since no load is applied to the first contact portion, no damage due to fretting occurs.

In the pipe joint assembled as described above, the maximum interference of the gasket 40 is regulated, and the gasket 40 is not directly exposed to high-temperature exhaust gas. Since the pipe 20 is also prevented from rotating in the circumferential direction and does not rub the gasket 40 in the circumferential direction, the gasket 40 has high reliability and durability.

[0023]

According to the present invention, the existence of the first flange is provided.
The thickness of the space between the bulge and the flare,
Gasket closing is regulated. Even if the tightening torque of the bolt is increased, the interference of the gasket interposed between the bulging portion and the flare portion can be restricted to the gasket interference when the second flanges of the clamps abut . First
Regulation of gasket tightening due to flange and second franc
Double regulation with gasket overtightening due to zero gap
Control to prevent damage due to overtightening of gasket bolts.
The reliability can be reliably prevented, and the reliability and durability of the sealing performance of the pipe joint can be greatly improved.

[Brief description of the 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. 2;

FIG. 3 is a plan view of the clamp of FIG. 2;

FIG. 4 is a perspective view of the vicinity of a second flange portion of the clamp of FIG. 2;

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

FIG. 6 is a cross-sectional view of the pipe joint of FIG. 1 taken along line AA.

FIG. 7 is a sectional view of the first pipe taken along line BB of the pipe joint of FIG. 6;

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 10 1st pipe 11 bulge part 12 straight part 13 recessed part 20 2nd pipe 21 flare part 22 1st flange 23 straight part 24 straight part 25 convex part 30 clamp 31 cut 32 second flange 33 bendable part 34 Cross section angled portion 35 Flange 36 Central part of second flange 37 Bolt hole 40 Gasket 50 Bolt 51 Nut

Continuation of the front page (58) Field surveyed (Int. Cl. ⁷ , DB name) F16L 23/00-23/24 F16L 19/00-19/14

Claims (1)

(57) [Claims] 1. A first pipe, a flare portion which is expanded in a radial direction having an end portion a bulge bulging radially outwardly circumferentially extending, and the bulging portion bent from said flared portion The tip extends toward
When it hits the part, the thickness between the bulging part and the flare part
A second pipe having an end with a first flange forming a regulated space , having a cut with a second flange at one location in the circumferential direction, having a bendable portion on the opposite side to the cut, The cross-sectional shape of the portion excluding the cut and the bendable portion is formed into a chevron shape so as to be able to come into contact with the bulging portion and the flare portion from the outer peripheral side. And a clamp having a second inter-flange spacing set so that the tip of the flange contacts the outer surface of the bulging portion, and the clamp is inserted into the space formed between the bulging portion and the flare portion.
A gasket, comprising: a gasket;