JP3308782B2 - Plug-in joint structure - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

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

[0002]

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

FIG. 5 shows an example of an exhaust system of an automobile, in which an engine 1 to an exhaust pipe 3, a catalytic converter 5, an exhaust pipe 7,
The prim muffler 9, the exhaust pipe 11, the main muffler 13, and the tail pipe 15 are connected in this order. In this type of exhaust system, a connecting portion 17 usually called a simple joint may be provided in the exhaust pipe, as indicated by reference numeral 17. FIG. 6 shows details of the connecting portion 17. The connecting portion 17 has a male pipe 23 inserted into one end of a female pipe 19 with a gasket 21 having a tapered cross section therebetween.
The two pipes 19 and 23 are connected by being clamped by a clamp 25 having a chevron section having 5a. In particular, an expanded flare 19a is provided at one end of the female pipe 19, and the male pipe 23 has a slight protrusion 23a which stops the axial movement of the gasket 21 and engages with the clamp 23.
Is provided. The gasket 21 is pressed by the flare 19a of the female pipe 19 and one slope 25a of the angled cross-section of the clamp 25 to deform the gasket 21, and the bottom of the tapered cross-section of the male pipe 23 is formed by the male pipe 23. This seals the male pipe 23 in close contact with the outer periphery.

[0004]

However, in the structure using the clamp 25 as described above, there is a possibility that the seal of the connecting portion 17 becomes unstable. That is, the clamp 2
As the gasket 21 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. First, one side of the clamp 25 is engaged with the projection 23a, It rotates as shown by the arrow and becomes as shown in FIG. In this case, in the tightening state, there is a gap in the portion A, and the tightening force is shared by B, C and D.
a is in the form of a leaf spring and is receiving a tightening force by the elastic gasket 21, so that 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 operation difficult. Accordingly, it has been difficult to obtain a stable tightening state of the gasket 21.

Accordingly, an object of the present invention is to provide a bayonet joint structure capable of easily obtaining a stable tightened state.

[0006]

According to a first aspect of the present invention, an outer fitting portion is provided on a first tube through a first inclined portion which expands and inclines radially outward. Along with
A window penetrating the outer fitting portion is provided, and an inner fitting portion fitted inside the outer fitting portion is provided in a second pipe connected to the first pipe, and the inner fitting portion is provided. A second inclined portion which inclines radially inward toward the distal end side in the fitting direction and faces the first inclined portion.
And a groove in the circumferential direction in which a corner on the front side in the fitting direction faces the window when the two slopes maintain a predetermined interval before the connection of the two pipes on the outer peripheral surface of the inner fitting portion. A substantially ring-shaped clamp which is attached to the outside of the outer fitting portion and is fastened to the outer peripheral surface of the outer fitting portion by fastening means, and partially enters the window portion before being fastened to the clamp. And having the inclined cam surface facing the corner portion, pressing the corner portion by the inclined cam surface by entering the groove portion in response to the tightening, moving the inner fitting portion in the fitting direction, and moving the two inclined portions. And a substantially ring-shaped sealing material having elasticity that is interposed between the two inclined portions, is crushed by a change in the interval between the two inclined portions, and seals between the two inclined portions. It is characterized by.

When connecting the two tubes, the inner fitting portion of the second tube is fitted to the outer fitting portion of the first tube, 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 so as to maintain a predetermined interval before coupling via a sealing material.
Next, the clamp is fitted into the outer fitting portion, the cam projection faces the window, and the inclined cam surface faces the corner of the groove 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 projection enters the groove of the inner fitting portion, and at the same time, the inclined cam surface presses the corner of the groove to further move the inner fitting portion in the fitting direction, and the interval between the two inclined portions becomes smaller. The sealing member 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 securely clamped by both inclined portions.

According to a second aspect of the present invention, there is provided the bayonet joint structure according to the first aspect, wherein the clamp is formed in a C-ring shape, and the fastening means is provided at both free ends of the clamp at a predetermined distance from each other. A pair of tongue pieces for fastening facing each other, a through hole provided in the one tongue piece, and a nut part provided in the other tongue piece, are inserted through the through hole and fastened to the nut part. And a bolt.

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

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

Then, a pair of cam projections of the clamp enter through a pair of windows opposed in the radial direction of the outer fitting portion, and press the corners of the groove by the two cam projections. The force can be reliably converted as the axial force of the fitting portion.

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

When the cam projection enters the window and the inclined cam surface faces the corner of the groove, the window stopper engages with the window, and the inner stopper is engaged with the outer fitting portion before the clamp is fastened. The detachment of the fitting portion can be restricted.

According to a fifth aspect of the present invention, there is provided the plug-in joint structure according to any one of the first to fourth aspects, wherein the cam projection engages with the groove when the cam projection enters the groove. It is characterized by having.

When the cam projection enters the groove,
The groove stopper surface is engaged with the groove, and the window stopper surface is engaged 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 plug-in 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.

Further, 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 cross-sectional views of a bayonet joint structure according to an embodiment of the present invention.
(A) shows the state before clamping, and (b) shows the state after clamping.

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 approximately 45 degrees. ing. The outer fitting portion 31 is provided with a penetrating window 33 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 distal end side of the inner fitting portion 37 in the fitting direction so as to incline inward in the radial direction and face the first inclined portion 29. The first pipe 27 is provided at the distal end 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 43 is provided on the outer peripheral surface of the inner fitting portion 37. The groove 43 is provided, for example, on the entire circumference.
Is formed 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. A corner 43a on the front side in the fitting direction of the groove 43 is formed with a rounded portion, and the two inclined portions 29, 39 maintain a predetermined interval before the two pipes 27, 35 are joined as shown in FIG. In the state, it is in a position facing the window 33. A clamp 45 is mounted outside the outer fitting portion 31 of the first tube 27. A cam projection 47 is provided on the clamp 45 so as to project inward in the radial direction. The cam projection 47 has 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 interval 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 projection 47 is such that the clamp 45 is
When it is in close contact with the groove 43, it is formed so as to enter the groove 43.

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

More specifically, the outer fitting portion 31 of the first tube 27 is as shown in FIG. That is, a pair of the window portions 33 are provided so as to face the outer fitting portion 31 in the radial direction, and are formed in a circumferentially long slot shape. Further, 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, the clamp 45 is formed in a C-ring shape with the clamp body 45a being substantially ring-shaped,
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, 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 on both sides of the tongue pieces 53a and 53b between the tongue pieces 53a and 53b and the clamp body 45a.

Next, the operation will be described.

First, before the inner and outer fitting portions 31 and 37 are fitted, the ring gasket 51 is placed on the small diameter portion 41 of the inner fitting portion 37.
Are fitted. Next, the inner fitting portion 37 is inserted into the outer fitting portion 31, and the second inclined portion 39 is inserted into the first inclined portion 29.
Are fitted so as to approach each other. This fitting state is a state before the ring gasket 51 comes into contact with the two inclined portions 29 and 39 and is tightened, and the two inclined portions 29 and 39 maintain a predetermined interval before the connection. At this time, the corner 43 a of the groove 43 faces the window 33. Next, the clamp 45 is attached, and the cam projection 47 is fitted into the window 33. Before the clamp 45 is fastened, the inclined cam surface 47 a of the cam projection 47 fitted into the window 33 comes into contact with the corner 43 a of the groove 43, and the window stopper surface 47 c engages with the window 33. In this state, even if a force in the pull-out direction acts on the inner fitting portion 37, the corner portion 43a becomes inclined cam surface 47a.
And the window stopper surface 47c is engaged with the window 33 to prevent 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 is inserted.
Of the outer fitting part 31
Tighten against As a result, the cam projection 47 enters the groove 43, the corner 43a is pressed by the inclined cam surface 47a, and the clamping force in the radial direction of the clamp 45 is reduced by the contact between the inclined cam surface 47a and the corner 43a. The force is reliably converted to the axial force of the fitting portion 37, and further moves in the direction in which the inner fitting portion 37 fits into the outer fitting portion 31. By this movement, the interval between the two inclined portions 29 and 39 changes so as to be narrow, and the ring gasket 51 is crushed. When the clamp 45 is tightened, the cam projection 47 is
3, the groove stopper surface 47b is engaged with the groove 43, and the window stopper surface 47c is engaged with the window 33. Therefore, the cam projection 47 exhibits a stopper function by the tightening of the clamp 45, and the fitting state of the inner and outer fitting portions 31, 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 outer fitting portion 31 is securely tightened to the inner fitting portion 37 by bending the slit 49,
A retaining force can be secured. Further, the axial force of the bolt 55 for tightening the clamp 45 by such a tightening structure is related to the tightening of the outer fitting portion 31 to the inner fitting portion 37 irrespective of the ring gasket 51 which is a soft material. However, 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 a sealing function having extremely high stability can be exhibited.

FIG. 4 is a table 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. It indicates that. That is, the ring gasket 51 is involved only in gas leak prevention, and the securing of the axial force involves the inner fitting portion 37 and the clamp 45. Therefore, a secure axial force and a stable sealing function can be obtained as described above.

It should be noted that in the state where the clamp 45 is completely tightened, the inclined cam surface 47a may be engaged with the corner 43a.

[0030]

As is clear from the above, according to the first aspect of the present invention, since the sealing material hardly affects the tightening force of the clamp, the tightening can be performed reliably. Further, the sealing material can be crushed at a constant interval between the inclined portions, and a stable sealing function can be exhibited.

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 tightening can be surely performed.

According to the third aspect of the present invention, the tightening force of the clamp can be reliably converted into the pressing force of the sealing material by the pair of windows and the cam projection, so that a reliable tightening and a stable sealing function can be obtained. Can be.

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

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

According to the sixth aspect of the present invention, it is possible to secure a secure axial force at the time of tightening a clamp in an exhaust pipe of an automobile exhaust system and to stably prevent gas leakage by a ring gasket.

[Brief description of the drawings]

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

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

FIG. 3 is a perspective view of a clamp.

FIG. 4 is a table showing functions of respective units.

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.

FIGS. 7A and 7B are cross-sectional views of a conventional example in which a tightening operation is being performed, and FIG. 7B is a cross-sectional view after the tightening operation.

[Explanation of symbols]

 3 Exhaust pipe 27 First pipe 29 First inclined part 31 Outer fitting part 33 Window part 35 Second pipe 37 Inner fitting part 39 Second inclined part 43 Groove part 43a Corner part 45 Clamp 47 Cam projection 47a Inclined cam surface 47b Groove stopper surface 47c Window stopper surface 51 Ring gasket (sealant) 53a, 53b Tongue piece 55 Bolt 59 Nut

──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Hiroshi Suzuki 2-50 Yayoi-cho, Higashi-Osaka-shi, Osaka Prefecture Inside Topura Co., Ltd. (72) Inventor Kazutake Takeguchi 2 Takaracho, Kanagawa-ku, Yokohama-shi, Kanagawa Nissan Motor Co., Ltd. Within the company (72) Inventor Hikaru Nakajima 2 Takaracho, Kanagawa-ku, Yokohama-shi, Kanagawa Nissan Motor Co., Ltd. (58) Field surveyed (Int.Cl. ⁷ , DB name) F16L 37/12 F01N 7/08

Claims (6)

(57) [Claims] An outer fitting portion is provided on a first pipe through a first inclined portion which expands and inclines radially outward, and a window portion penetrating the outer fitting portion is provided; The second pipe connected to the pipe is provided with an inner fitting part fitted inside the outer fitting part, and is reduced and inclined radially inward to a distal end side in the fitting direction of the inner fitting part. A second inclined portion opposed to the first inclined portion, and a corner portion on a front side in a fitting direction when the both inclined portions maintain a predetermined interval on an outer peripheral surface of the inner fitting portion before the two pipes are joined; Is provided with a circumferential groove facing the window, and provided with a substantially ring-shaped clamp which 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. It has a sloped cam surface that partially enters the window before tightening and faces the corner, A cam projection is provided by pressing the corner portion by the inclined cam surface by entering the groove portion to move the inner fitting portion in the fitting direction to narrow the interval between the two inclined portions, and to interpose between the two inclined portions. A plug-in joint structure characterized by providing a substantially ring-shaped sealing material which is crushed by a change in the interval between the two inclined portions and has an elasticity for sealing between the two inclined portions. 2. The plug-in joint structure according to claim 1, wherein said clamp is formed in a C-ring shape, and said fastening means is opposed to both free ends of said clamp at a predetermined interval from each other. A pair of tongue pieces, a through hole provided in the one tongue piece, a nut part provided in the other tongue piece, and a bolt inserted through the through hole and fastened to the nut part. A bayonet joint structure characterized by the above. 3. The plug-in joint structure according to claim 1, wherein a pair of the window portions is provided so as to face the outer fitting portion in a radial direction, and the cam protrusion is provided on the clamp. A plug-in joint structure comprising a pair provided so as to oppose each other in a radial direction. 4. The plug-in joint structure according to claim 1, wherein said cam projection engages with said window on a side opposite to a fitting direction of said inclined cam surface. A bayonet joint structure having a surface. 5. The bayonet joint structure according to claim 1, wherein the cam projection has a groove stopper surface that engages with the groove when the cam protrusion enters the groove. And the plug joint structure. 6. The plug-in joint structure according to claim 1, wherein the first pipe and the second pipe are exhaust pipes of an automobile exhaust system, and the seal member is a ring gasket. A plug-in joint structure, characterized in that: