JPH11159677A - Connecting structure of exhaust pipe - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent slipping-out by fitting a connecting end part of an inner tube in an connecting end part of an outer tube having slits, arranging an engaging hole in either one of the outer tube or the inner tube of a fitting part, and arranging an engaging projection to engage with the engaging hole on the other inner tube or outer tube side. SOLUTION: An elastic piece 27b of an outer tube 27 sandwiched between two slits 31 possesses a rectangular engaging hole 33. While, an engaging projection 35 engageable with an engaging hole 33 at connecting time to the outer tube 27 is protrusively arranged outward on a peripheral wall of an inner tube 29. In the engaging projection 35, a fitting directional side inclined face is formed in a gentler cross-sectional almost chevron shape in an inclination than a slipping-out directional side inclined face, and the inner tube 29 can be easily inserted/fitted in a connecting end part 27a by such a structure. Since a required process is only to fasten the outer periphery of a fitting part by a fastening metal fitting after engaging the engaging projection 35 with the engaging hole 33, the engaging projection 35 prevents rotation of the inner tube 29 by engaging with the engaging hole 33, and can also reliably prevent slipping-out of the inner tube 29.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a connection structure of an exhaust pipe mounted on a vehicle exhaust system.

[0002]

2. Description of the Related Art Conventionally, as a connection structure of an exhaust pipe mounted on a vehicle exhaust system, Japanese Unexamined Utility Model Publication No. 5-96430 or FIG.
As shown in the figure, a gasket 9 is interposed between flanges 5 and 7 welded to the outer periphery of each connection end of two exhaust pipes 1 and 3 to be connected, and both flanges 5 and 7 are bolted (not shown). Alternatively, as shown in JP-A-5-133474 or FIG. 8, a slit 15 is formed on the connection end 11a side of one exhaust pipe (outer pipe) 11 of the exhaust pipes 11 to be connected.
Is formed, and the connection end 13a of the other exhaust pipe 13 (inner pipe) is fitted to the large-diameter part 17. Support 21,
Nut 2 to be screwed to screw portion 19a of U-shaped bolt 19
3 and the like are widely known.

[0003]

However, in the exhaust pipe connection structure shown in FIG. 8, the nut 23 is loosened due to vibration during running of the vehicle or the exhaust pipe 11,
It is pointed out that when the rusting of the exhaust pipe 13 occurs, the exhaust pipe 13 gradually shifts in the circumferential direction and falls off from the exhaust pipe 11.

On the other hand, the flange connection shown in FIG. 7 is excellent in preventing the exhaust pipe 1.3 from coming off, but the flanges 5 and 7 must be welded to the outer periphery of the exhaust pipes 1 and 3. Therefore, there is a problem that cracks are generated due to intergranular corrosion due to welding, and further, the manufacturing cost is high and the maintainability is poor compared with the connection structure shown in FIG.

The present invention has been devised in view of the above circumstances, and is an improvement over the conventional example of FIG. 8 which is inexpensive to manufacture, and has a long-term use by preventing the exhaust pipe from coming off. The purpose of the present invention is to provide a connection structure.

[0006]

In order to achieve the above object, according to the first aspect of the present invention, a connection end of an inner tube is fitted into a connection end of an outer tube provided with a slit, and this fitting is performed. In the exhaust pipe connection structure in which the outer periphery of the fitting portion is tightened with a fastener, an engagement hole is provided in one of the outer tube and the inner tube of the fitting portion, and the engagement hole engages with the engagement hole. The joint projection is provided on the other inner tube or outer tube side.

The invention according to claim 2 is based on claim 1
In the connection structure for an exhaust pipe described above, the engagement projection is formed to have a substantially sloped cross section with a gentle inclination on the fitting direction side and a sharp inclination on the removal direction side.

(Operation) According to the invention of each claim, the engagement projection engages with the engagement hole to prevent the rotation of the inner tube and to prevent the inner tube from being pulled out.

According to the second aspect of the present invention, the engaging projection is formed in a substantially V-shaped cross section in which the inclined surface on the fitting direction side is gentler in inclination than the inclined surface on the disengagement direction side. ,
The engaging projections facilitate the fitting of the inner tube into the outer tube, and reliably prevent the connected inner tube from being removed.

[0010]

Embodiments of the present invention will be described below in detail with reference to the drawings.

FIGS. 1 to 3 show an exhaust pipe connection structure according to an embodiment of the present invention.
Numerals 7 and 29 denote an outer tube and an inner tube to be connected, respectively. Four slits 31 are formed at the connection end 27a of the outer tube 27 at intervals of 90 ° in the circumferential direction as shown in FIG. In the same manner as in the conventional example shown in FIG.
The outer tube 27 and the inner tube 29 are connected by fitting the connection end portion 29a of the inner tube 29 into the inner tube 29a and tightening the outer periphery of the fitted portion with a fastener (not shown).

The present embodiment has the following features in addition to the above-described conventional configuration for the purpose of preventing the inner tube 29 from coming off. That is, in FIG. 1, reference numeral 27b denotes an elastic piece of the outer tube 27 sandwiched between the two slits 31, and a rectangular engaging hole 33 is formed in the elastic piece 27b. On the other hand, as shown in FIG. 2, an engagement protrusion 35 that can be engaged with the engagement hole 33 at the time of connection with the outer tube 27 is provided on the peripheral wall of the inner tube 29 so as to protrude outward.

The engaging projection 35 is formed in a substantially V-shaped cross section in which the inclined surface 35a in the fitting direction is gentler in inclination than the inclined surface 35b in the disengagement direction. In addition to facilitating insertion and fitting of the inner tube 29 into the end portion 27a, the engagement protrusion 35 engaged with the engagement hole 33 is provided.
However, the inner tube 29 connected to the outer tube 27 is prevented from coming off.

Since the present embodiment is configured as described above, the connection between the outer pipe 27 and the inner pipe 29 is made by the engagement projection 35.
While pushing the elastic piece 27b upward with the inclined surface 35a,
Insert the connection end 29a of the inner tube 29 into the connection end 27a,
After the engagement and the engagement protrusion 35 are engaged with the engagement hole 33, the outer periphery of the engagement portion may be tightened with a fastener (not shown). And inner pipe 29
, And the inner tube 29 is surely prevented from coming off.

Therefore, according to the present embodiment, even if the nut of the fastener is loosened by the vibration during running of the vehicle or the outer tube 27 and the inner tube 29 are rusted due to long-term use, the inner tube 29 is circumferentially moved. It is possible to prevent the tube from gradually falling and falling out of the outer tube 27. According to this embodiment,
As in the conventional example shown in FIG. 8, there are advantages that the manufacturing cost is low and the maintainability is excellent.

4 to 6 show an exhaust pipe connection structure according to an embodiment of the present invention. In FIG. 4, reference numerals 37 and 39 denote an outer pipe and an inner pipe to be connected. Similarly, outer tube 3
As shown in FIG. 6, the connecting end 37a of
The four slits 31 are formed in the axial direction at an interval of °, and the connection end 39a of the inner tube 39 is fitted into the connection end 37a, and the outer periphery of this fitting portion is not shown. The outer tube 37 and the inner tube 39 are tightened by the fastening metal.
Are connected.

In this embodiment, as shown in FIG. 5, the elastic piece 37b of the outer tube 37 interposed between the two slits 31 projects inward to prevent the connected inner tube 39 from being pulled out. An engaging protrusion 41 having an arcuate cross section is formed, and an engaging hole 43 is formed in the peripheral wall of the inner tube 39 so as to correspond to the engaging protrusion 41.
It is characterized by having provided. Since the present embodiment is configured as described above, in order to connect the outer tube 37 and the inner tube 39, the elastic piece 37 b is pushed upward at the outer periphery of the inner tube 39 abutting on the engagement projection 41 while spreading. The connection end 39a of the inner tube 39 is inserted and fitted into the connection end 37a, and the engagement protrusion 41 is inserted.
After engaging with the engaging hole 43, the outer periphery of the fitting portion may be tightened with a fastener (not shown), and the engaging protrusion 41 engages with the engaging hole 43 to prevent the inner tube 39 from rotating. At the same time, the inner tube 39 is prevented from coming off.

Therefore, according to the present embodiment, even if the nut of the fastener is loosened due to the vibration during traveling of the vehicle or the outer tube 37 and the inner tube 39 are rusted due to the use for a long period, the inner tube 39 extends in the circumferential direction. It does not slip out of the outer tube 37. Also, this embodiment has the advantage that the manufacturing cost is low and the maintainability is excellent, as in the conventional example shown in FIG.

[0019]

As described above, according to the exhaust pipe connection structure according to each of the claims, the nut of the fastener is loosened by the vibration during the running of the vehicle or the outer pipe and the inner pipe become loose due to long-term use. Even if it rusts, it is possible to prevent the inner pipe from shifting in the circumferential direction and falling off from the outer pipe. Also, according to the present invention, the manufacturing cost is lower than the conventional flange connection,
Also, it has an advantage of excellent maintainability.

[Brief description of the drawings]

FIG. 1 is a plan view of a connection structure of an exhaust pipe according to an embodiment of the present invention.

FIG. 2 is a sectional view taken along line II-II of FIG.

FIG. 3 is a sectional view taken along line III-III of FIG. 1;

FIG. 4 is a plan view of the exhaust pipe connection structure according to the first embodiment of the present invention;

FIG. 5 is a sectional view taken along line VV of FIG. 4;

FIG. 6 is a sectional view taken along line VI-VI of FIG. 4;

FIG. 7 is a side view of a conventional exhaust pipe connection structure using a flange.

FIG. 8 is a side view of a conventional exhaust pipe connection structure using a fastener.

[Explanation of symbols]

 27, 37 Outer pipe 27a, 37a, 29a, 39a Connection end 29.39 Inner pipe 31 Slit 33, 43 Engagement hole 35, 41 Engagement projection

Claims (2)

[Claims] In the exhaust pipe connection structure, a connection end of an inner pipe is fitted into a connection end of an outer pipe provided with a slit, and an outer periphery of the fitting portion is tightened with a fastener. An engaging hole is provided on one of the outer tube and the inner tube of the fitting portion, and an engaging projection for engaging with the engaging hole is provided on the other inner tube or the outer tube. Exhaust pipe connection structure. 2. The engaging projection has a gentle inclination on the fitting direction side,
2. The exhaust pipe connection structure according to claim 1, wherein the inclination in the pullout direction side is formed in a substantially cross-sectionally substantially letter shape.