JPH09133279A - Insert joint structure - Google Patents

Abstract

PROBLEM TO BE SOLVED: To ensure complete fastening of a clamp and stable seal function. SOLUTION: An outer fitting part 31 is arranged on a first pipe 27, a window part 33 is arranged, an inner fitting part 37 is arranged on a second pipe 35, a second inclining part 39 is arranged, the groove part 43 of a circumferential direction is arranged, a nearly ring shaped cramp 45 fastened by fastening means is arranged. A cam projection part 47 is arranged by forming in such a constitution that an inclining cam surface 47a is arranged on the cramp 45, a corner part 43a is push-pressed by the inclining cum surface 47a, the inner fitting part 37 is moved to a fitting direction, and a clearance between both inclining parts 29, 39 is narrowed. A nearly ring shaped seal material 51 interposed between both inclining parts 29, 39 is arranged. It is thus possible to convert fastening force of the cramp 45 into force of a direction which the seal material 51 is broken by the inclining cam surface 47a, and also it is possible to ensure assured axial force and stable seal function.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a plug joint structure for an automobile exhaust pipe or the like.

[0002]

2. Description of the Related Art As a conventional plug-in joint structure of this type, for example, there is one as shown in FIGS. 5 and 6 (see Japanese Utility Model Laid-Open No. 6-012713).

FIG. 5 shows an example of an automobile exhaust system, which includes an engine 1, an exhaust pipe 3, a catalytic converter 5, an exhaust pipe 7,
The primary muffler 9, the exhaust pipe 11, the main muffler 13, and the tail pipe 15 are sequentially connected. In this type of exhaust system, a connecting portion 17, which is usually called a simple joint, may be provided in the middle of the exhaust pipe as indicated by reference numeral 17. Details of this connecting portion 17 are shown in FIG. The connecting portion 17 is such that a male pipe 23 is inserted into one end of a female pipe 19 with a rice ball-shaped gasket 21 having a cross-sectional shape sandwiched between the female pipe 19 and the slope 2
It is structured such that both pipes 19 and 23 are connected by tightening with a clamp 25 having a mountain-shaped cross section having 5a. In particular, an expanded flare 19a is provided at one end of the female pipe 19, and a slight protrusion 23a for stopping the axial movement of the gasket 21 and engaging with the clamp 23 is provided on the male pipe 23.
Is provided. Then, the sloped surface of the gasket-shaped cross section of the gasket 21 is pressed by the flare 19a of the female pipe 19 and the one sloped surface 25a of the mountain-shaped cross section of the clamp 25 to deform the gasket 21, and the bottom surface of the diaper-shaped cross section of the male pipe 23. The outer pipe is closely adhered to and seals with the male pipe 23.

[0004]

However, in the structure using the clamp 25 as described above, the seal of the connecting portion 17 may become unstable. That is, the clamp 2
When 5 is tightened, the displacement of the clamp 25 changes from a two-dot chain line to a solid line as shown in FIG. 7A due to the deformation of the gasket 21, and the protrusion 23a first engages with one side of the clamp 25, The image is rotated as shown by the arrow and becomes as shown in FIG. In this case, in the tightened state, there is a gap in the portion A, and the tightening force is shared by B, C, and D, but the flare 19
Since a is a leaf spring shape and the tightening force is received by the elastic gasket 21, the tightening force of the clamp 25, that is, the axial force of the bolt for tightening the clamp 25 is not stable, which makes the tightening work difficult. Therefore, it is difficult to obtain a stable tightened state of the gasket 21.

Therefore, an object of the present invention is to provide a plug joint structure which can easily obtain a stable tightened state.

[0006]

In order to solve the above-mentioned problems, the invention of claim 1 provides an outer fitting portion on a first pipe via a first inclined portion which is enlarged and inclined outward in the radial direction. With
A window portion is provided through the outer fitting portion, an inner fitting portion that fits inside the outer fitting portion is provided in a second pipe that is coupled to the first pipe, and the inner fitting portion is provided. A second end facing the first inclined part with a reduction inward inward in the radial direction toward the tip side in the fitting direction of
And a groove portion in the circumferential direction in which a corner portion on the front side in the fitting direction faces the window portion when the both inclined portions maintain a predetermined distance before the two pipes are coupled to each other on the outer peripheral surface of the inner fitting portion. And a substantially ring-shaped clamp that is mounted on the outside of the outer fitting portion and is fastened to the outer peripheral surface of the outer fitting portion by fastening means, and partly enters the window portion before fastening to the clamp. Has an inclined cam surface facing the corner portion and enters the groove portion in accordance with the tightening, and the inclined cam surface presses the corner portion to move the inner fitting portion in the fitting direction. A cam protrusion that narrows the gap between the inclined portions is provided, and a substantially ring-shaped sealing material having elasticity that is interposed between the inclined portions and is crushed by a change in the distance between the inclined portions to seal between the inclined portions is provided. Is characterized by.

When connecting the two pipes, the inner fitting portion of the second pipe is fitted to the outer fitting portion of the first pipe, and the inner fitting portion is fitted to the first inclined portion of the outer fitting portion. The second inclined portion of the portion is arranged via the sealing material so as to maintain a predetermined distance before coupling.
Next, the clamp is fitted into the outer fitting portion, the cam projection is exposed from the window portion, and the inclined cam surface is opposed to the corner portion of the groove portion of the inner fitting portion. Next, the clamp is fastened to the outer peripheral surface of the outer fitting portion by the fastening means. By this tightening, the cam protrusion enters the groove of the inner fitting portion, and at the same time, the inclined cam surface presses the corner portion of the groove portion to further move the inner fitting portion in the fitting direction. The sealing material is pressed by the narrowing, and the coupling by tightening the clamp is completed. Therefore, the clamping force of the clamp is reliably converted into the axial force of the inner fitting portion by the inclined cam surface, and the sealing material can be reliably clamped by both the inclined portions.

A second aspect of the present invention is the insertion joint structure according to the first aspect, wherein the clamp is formed in a C-ring shape, and the fastening means are spaced from each other at both free ends of the clamp by a predetermined distance. A pair of fastening tongues facing each other, a through hole provided in the one tongue piece, and a nut portion provided in the other tongue piece, and inserted through the through hole and fastened to the nut portion. It is characterized in that it is configured with bolts.

Since the clamp has a C-ring shape, it can be easily attached to the outer fitting portion. Further, the bolt can be inserted through the through hole of one tongue piece of the clamp and fastened to the nut portion of the other tongue piece, whereby the clamp can be securely fastened to the outer fitting portion.

A third aspect of the present invention is the insertion joint structure according to the first or second aspect, wherein a pair of the window portions are provided in the outer fitting portion so as to face each other in the radial direction, and the cam projection portion is provided. Are provided so as to face each other in the radial direction of the clamp.

A pair of cam projections of the clamp enter through a pair of windows facing each other in the radial direction of the outer fitting portion, and the corners of the groove are pressed by the two cam projections. The force in the axial direction of the fitting portion can be reliably converted.

A fourth aspect of the present invention is the insertion joint structure according to any one of the first to third aspects, wherein the cam projection is engaged with the window on the side opposite to the fitting direction of the inclined cam surface. It is characterized by having a matching window stopper surface.

Then, when the cam projection enters the window and the inclined cam surface faces the corner of the groove, the window stopper engages the window, and the inner fitting to the outer fitting portion occurs before fastening the clamp. It is possible to regulate the disengagement of the fitting portion.

A fifth aspect of the present invention is the insertion joint structure according to any one of the first to fourth aspects, wherein the cam protrusion engages with the groove when the cam protrusion enters the groove. It is characterized by having.

When the cam projection enters the groove,
The groove stopper surface engages with the groove, and the window stopper surface engages with the window, so that the fastening state of the sealing material can be reliably maintained in the clamp fastening state.

The invention according to claim 6 is the insertion joint structure according to any one of claims 1 to 5, wherein the first pipe and the second pipe are exhaust pipes of an automobile exhaust system, The sealing material is a ring gasket.

The tightened state of the ring gasket can be reliably maintained in the exhaust pipe of the automobile exhaust system.

[0018]

1 (a) and 1 (b) are sectional views of a plug joint structure according to an embodiment of the present invention.
(A) shows the state before the clamp fastening and (b) shows the state after the clamp fastening.

As shown in FIGS. 1 and 2, an outer fitting portion 31 is provided on a first pipe 27, which is an exhaust pipe of an automobile exhaust system, via a first inclined portion 29 inclined at about 45 degrees. ing. A window portion 33 that penetrates the outer fitting portion 31 is provided at an intermediate portion in the fitting direction.

A second tube 35 connected to the first tube 27.
Is provided with an inner fitting portion 37 that fits inside the outer fitting portion 31. A second inclined portion 39 of approximately 45 degrees is provided on the tip end side of the inner fitting portion 37 in the fitting direction so as to be inclined inward in the radial direction and to face the first inclined portion 29. The first pipe 27 is provided on the tip side of the second inclined portion 39 in the fitting direction.
Is provided with a small diameter portion 41 that fits on the inner diameter side. A circumferential groove portion 43 is provided on the outer peripheral surface of the inner fitting portion 37. The groove portion 43 is provided on, for example, the entire circumference, and the groove portion 43
The front-rear width in the fitting direction is slightly larger than the front-rear width of the window 33, and the same depth does not protrude inward from the inner diameter of the first pipe 27 so as not to cause exhaust resistance. Has become. The corner portion 43a on the front side in the fitting direction of the groove portion 43 is formed to have a rounded portion, and both the inclined portions 29 and 39 maintain a predetermined interval before the pipes 27 and 35 are coupled to each other. In the state, it is located so as to face the window 33. A clamp 45 is attached to the outside of the outer fitting portion 31 of the first pipe 27. A cam protrusion 47 is provided on the clamp 45 so as to protrude inward in the radial direction. The cam protrusion 47 is provided with an inclined cam surface 47a on the front side in the fitting direction, a groove stopper surface 47b on the front side in the fitting direction, and a window stopper surface 47c on the rear side. The space between the stopper surfaces 47b and 47c is formed to be slightly smaller than the width of the window 33. The height of the cam protrusion 47 is set such that the clamp 45 has the outer fitting portion 31.
It is formed so as to enter the groove portion 43 when it is in close contact with.

A ring gasket 51 is provided as a ring-shaped sealing material between the inclined portions 29 and 39.

More specifically, the outer fitting portion 31 of the first pipe 27 is as shown in FIG. That is, a pair of the window portions 33 are provided so as to face each other in the radial direction of the outer fitting portion 31, and are formed in the shape of an elongated hole in the circumferential direction. A pair of slits 49 are formed in the outer fitting portion 31 between the window portions 33.

The clamp 45 is as shown in FIG. That is, in the clamp 45, the clamp main body 45a is formed in a C ring shape as a substantially ring shape, and the cam protrusion 47 is formed.
Are provided so as to face each other in the radial direction of the clamp 45. The clamp 45 is provided with a pair of tongue pieces 53a and 53b and a bolt 55 as fastening means. One tongue piece 53a is provided with a through hole 57, and the other tongue piece 53b is provided with a nut portion 59. Reinforcing ribs 61 are provided between the tongue pieces 53a and 53b on both sides of the clamp body 45a.

Next, the operation will be described.

First, before the inner and outer fitting portions 31 and 37 are fitted, a ring gasket 51 is placed on the small diameter portion 41 of the inner fitting portion 37.
Are fitted together. Then, the inner fitting portion 37 is inserted into the outer fitting portion 31, and the first tilted portion 29 and the second tilted portion 39 are inserted.
Fit so that they are close to each other. This fitting state is a state before the ring gasket 51 is in contact with both the inclined portions 29 and 39 and is tightened, and both the inclined portions 29 and 39 maintain a predetermined interval before being joined. At this time, the corner 43 a of the groove 43 faces the window 33. Next, the clamp 45 is attached and the cam protrusion 47 is fitted into the window 33. Before the clamp 45 is fastened, the inclined cam surface 47a of the cam projection 47 fitted into the window 33 contacts the corner 43a of the groove 43, and the window stopper surface 47c engages the window 33. In this state, even if a force is applied to the inner fitting portion 37 in the pulling-out direction, the corner portion 43a is inclined by the inclined cam surface 47a.
The window stopper surface 47c engages with the window 33 and restricts the inner fitting portion 37 from coming off.

Next, the bolt 55 is inserted through the through hole 57 of one tongue piece 53a of the clamp 45, and the other tongue piece 53b.
It is fastened to the nut portion 59 of the and the clamp 45 is attached to the outer fitting portion 31.
Tighten against. As a result, the cam protrusion 47 enters the groove 43, the corner portion 43a is pressed by the inclined cam surface 47a, and the tightening force in the radial direction of the clamp 45 is caused by the abutting action of the inclined cam surface 47a and the corner portion 43a. The force in the axial direction of the fitting portion 37 is reliably converted, and the inner fitting portion 37 further moves in the direction of fitting to the outer fitting portion 31. By this movement, the distance between the inclined portions 29 and 39 changes so as to become narrow, and the ring gasket 51 is crushed. In the clamped state of the clamp 45, the cam protrusion 47 has the groove 4
3, the groove stopper surface 47b engages with the groove 43, and the window stopper surface 47c engages with the window 33. Therefore, when the clamp 45 is tightened, the cam protrusion 47 acts as a stopper, and the fitting state of the inner and outer fitting portions 31 and 37 can be reliably maintained in the tightened state of the ring gasket 51. Further, when the outer fitting portion 31 is tightened by the clamp 45, the slit 49 bends to securely tighten the outer fitting portion 31 to the inner fitting portion 37.
A retaining force can be secured. Further, since the axial force of the bolt 55 that tightens the clamp 45 by such a tightening structure is involved in tightening the outer fitting portion 31 to the inner fitting portion 37 regardless of the ring gasket 51 which is a soft material, the axial force. Is stable and secure tightening can be performed.

Further, when the tightening of the clamp 45 is completed, the distance between the first inclined portion 29 and the second inclined portion 39 is always constant, so that the ring gasket 51 is crushed between the inclined portions 29 and 39. The state is constant and the sealing function with extremely high stability can be exhibited.

FIG. 4 is a diagram showing that the outer fitting portion 31, the inner fitting portion 37, the clamp 45, and the ring gasket 51 are related to each function, and circles relate to this function. It indicates that That is, the ring gasket 51 is involved only in preventing gas leakage, and the inner fitting portion 37 and the clamp 45 are involved in ensuring axial force. Therefore, it is possible to obtain a reliable axial force and a stable sealing function as described above.

In addition, when the clamp 45 is completely tightened, the inclined cam surface 47a may be engaged with the corner portion 43a.

[0030]

As is apparent from the above, according to the first aspect of the present invention, since the sealing material hardly participates in the clamping force of the clamp, the clamping can be reliably performed. Moreover, the sealing material can be crushed at a constant interval of the inclined portion, and a stable sealing function can be exerted.

According to the second aspect of the present invention, the clamp can be fastened by the bolt and the nut portion, the axial force of the bolt can be stably obtained, and the secure fastening can be performed.

According to the third aspect of the present invention, the tightening force of the clamp can be surely converted into the pressing force of the seal material by the pair of the window portion and the cam projection, and a reliable tightening and a stable sealing function can be obtained. You can

According to the fourth aspect of the present invention, the action of the window stopper surface enables the outer fitting portion and the inner fitting portion to be positioned in the pulling direction even before the clamp is tightened.

According to the fifth aspect of the present invention, by the action of the groove stopper surface, the outer fitting portion and the inner fitting portion can be positioned in the pulling-out direction after the clamp is tightened, and a stable sealing function can be exhibited. .

According to the sixth aspect of the present invention, it is possible to secure a reliable axial force when clamping the clamp in the exhaust pipe of the automobile exhaust system and to prevent the stable gas leakage by the ring gasket.

[Brief description of the drawings]

FIG. 1 is a sectional view according to a first embodiment of the present invention,
(A) is sectional drawing before clamp tightening, (b) is sectional drawing after clamp tightening.

FIG. 2 is a perspective view of an outer fitting portion.

FIG. 3 is a perspective view of a clamp.

FIG. 4 is a chart showing the functions of each unit.

FIG. 5 is a schematic diagram illustrating an exhaust system of an automobile according to a conventional example.

FIG. 6 is a cross-sectional view according to a conventional example.

7A and 7B relate to a tightening action of a conventional example, FIG. 7A is a sectional view during tightening, and FIG. 7B is a sectional view after tightening.

[Explanation of symbols]

 3 Exhaust pipe 27 1st pipe 29 1st inclination part 31 Outer fitting part 33 Window part 35 2nd pipe 37 Inner fitting part 39 2nd inclination part 43 Groove part 43a Corner part 45 Clamp 47 Cam protrusion 47a Inclined cam surface 47b Groove part stopper surface 47c Window part stopper surface 51 Ring gasket (seal material) 53a, 53b Tongue piece 55 Bolt 59 Nut part

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Hiroshi Suzuki, 2-50 Yayoi-cho, Higashi-Osaka City, Osaka Prefecture Topura Co., Ltd. (72) Inventor Hajime Takeguchi, 2 Takara-cho, Kanagawa-ku, Yokohama-shi, Kanagawa Nissan Motor Co., Ltd. (72) Inventor Hikaru Nakajima 2 Takaracho, Kanagawa-ku, Yokohama-shi, Kanagawa Nissan Motor Co., Ltd.

Claims (6)

[Claims] 1. A first pipe is provided with an outer fitting portion via a first inclined portion that is enlarged and inclined outward in a radial direction, and a window portion penetrating the outer fitting portion is provided, and the first fitting portion is provided. An inner fitting portion that fits inside the outer fitting portion is provided on a second pipe that is coupled to the pipe, and the inner fitting portion is inclined toward the tip end side in the fitting direction in the radial direction to be reduced inward. A second sloped portion facing the first sloped portion is provided, and when the sloped portions maintain a predetermined distance on the outer peripheral surface of the inner fitting portion before the two pipes are joined, the corner portion on the front side in the fitting direction. Is provided with a circumferential groove portion facing the window portion, is provided on the outside of the outer fitting portion, and is provided with a substantially ring-shaped clamp that is fastened to the outer peripheral surface of the outer fitting portion by fastening means, and the clamp is attached to the clamp. Before tightening, it has an inclined cam surface that partially enters the window and faces the corner, By providing a cam protrusion that presses the corner portion by the inclined cam surface by moving into the groove portion and moves the inner fitting portion in the fitting direction to narrow the gap between the both inclined portions, the cam protrusion is interposed between the both inclined portions. A plug-in joint structure characterized in that a substantially ring-shaped sealing material having elasticity is provided which is crushed due to a change in the distance between the inclined parts and seals between the inclined parts. 2. The insertion joint structure according to claim 1, wherein the clamp is formed in a C-ring shape, and the fastening means are opposed to each other at predetermined intervals at both free ends of the clamp. A pair of tongue pieces, a through hole provided in the one tongue piece, a nut portion provided in the other tongue piece, and a bolt inserted through the through hole and fastened to the nut portion. A plug joint structure characterized in that 3. The insertion joint structure according to claim 1, wherein a pair of the window portions are provided in the outer fitting portion so as to face each other in the radial direction, and the cam protrusions are provided in the clamp. A pair of insertion joint structures is provided so as to face each other in the radial direction. 4. The insertion joint structure according to claim 1, wherein the cam protrusion engages with the window on the side opposite to the fitting direction of the inclined cam surface. A plug joint structure having a surface. 5. The insertion joint structure according to claim 1, wherein the cam protrusion has a groove stopper surface that engages with the groove when the cam protrusion enters the groove. And a plug joint structure. 6. The insertion joint structure according to claim 1, wherein the first pipe and the second pipe are exhaust pipes of an automobile exhaust system, and the sealing material is a ring gasket. It is a plug joint structure characterized by being.