JPH07239070A - Exhaust pipe joint - Google Patents

Abstract

PURPOSE:To provide an exhaust pipe joint which has an excellent sealing property and dispenses with welding, which is one of the causes of intergranular corrosion, to an exhaust pipe for thinning the exhaust pipe concerning the exhaust pipe joint. CONSTITUTION:Connection end parts 25a, 27a of exhaust pipes 25, 27 are expanded, while a cylindrical metal seal pressing member 31 mounted coaxially with the exhaust pipes 25, 27 is arranged between both of the connection end parts 25a, 27a, and a bellows metal seal member 29 which is welded on the outer circumference of the seal pressing member 31 at one end side and is shrunk by pressing force of both exhaust pipes 25, 27 so as to be brought into pressure contact with the inner circumferences of the both connection end parts 25a, 27a is formed along the outlines of the connection end parts 25a, 27a. A pair of plate flanges 33, 35 fitted around the outer circumferences of the connection end parts 25a, 27a so as to be fastened by bolts are provided.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an exhaust pipe joint for connecting exhaust pipes of a vehicle.

[0002]

2. Description of the Related Art Conventionally, as a joint for connecting exhaust pipes of a vehicle, for example, as shown in Japanese Utility Model Publication No. 62-170893 or FIG. 3, each connecting end portion of two exhaust pipes 1, 3 to be connected. Gasket 9 is interposed between flanges 5 and 7 welded to the outer circumference of 1a and 3a, and both flanges 5 and 7 are bolted, or as shown in FIG. 6, one of exhaust pipes 11 and 13 to be connected. The large diameter portion 15 is formed by enlarging the diameter of the connection end portion 11a side of the exhaust pipe 11, and the large diameter portion 15 is formed in the large diameter portion 15.
3 is fitted with the connection end portion 13a of the fitting 3, and the outer periphery of the fitting portion is made up of a U-shaped bolt 17, a support 19, and a nut 21 that is screwed to the threaded portion 17a of the U-shaped bolt 17.
Those tightened with No. 3 are widely known.

[0003]

The weight reduction of vehicles has been attempted as one means for achieving low pollution and high fuel consumption due to recent environmental problems and resource problems. Thinning is desired.

However, in the conventional joint shown in FIG. 3, it is difficult to reduce the thickness of the exhaust pipes 1 and 3 because the thick flanges 5 and 7 must be welded to the outer circumferences of the exhaust pipes 1 and 3. However, welding the exhaust pipes 1 and 3 may cause cracks in the exhaust pipes 1 and 3 due to intergranular corrosion.

Further, in the conventional structure shown in FIG. 4, the exhaust pipe 11,
13 can be made thin, but the large diameter portion 15 and the exhaust pipe 13
Unless the processing accuracy of the connecting end portion 13a is increased, the exhaust gas may leak from the gap caused by the processing distortion.

The present invention has been devised in view of the above circumstances, and is excellent in sealing property, and at the time of connecting exhaust pipes, the exhaust pipes are eliminated by eliminating welding to the exhaust pipes which causes intergranular corrosion. It is an object of the present invention to provide an exhaust pipe joint capable of reducing the wall thickness.

[0007]

In order to achieve such an object, a joint of an exhaust pipe according to the present invention has two exhaust pipes in which each connection end portion is expanded into a trumpet shape, and an exhaust pipe. A cylindrical metal seal pressing member that is mounted on the same axis as both exhaust pipes between the connection ends, and one end is welded to the outer periphery of the seal pressing member, and is contracted by the pressing force of both exhaust pipes to connect both From a bellows-shaped metal seal member that is pressed against the inner circumference of the end portion, and a pair of plate flanges that are molded along the outer shape of the connection end portion and are externally fitted to the outer circumference of each connection end portion and bolted It is characterized by

[0008]

According to the present invention, when a pair of plate flanges externally fitted to the respective connection ends of the exhaust pipe are bolted, the seal member contracts due to the pressing force of both exhaust pipes, and the outermost end of the seal member is compressed. The curved portion presses against the inner circumference of each connection end portion to ensure the sealing property between the curved portion and the connection end portion, and prevents exhaust gas from leaking.

Even if the exhaust pipe vibrates due to vehicle running, the bellows-shaped seal member absorbs the stress applied to the seal member by its curved portion being pressed against the inner circumference of each connection end and deformed freely. In addition, the seal holding member allows the exhaust gas in the exhaust pipe to smoothly flow down, prevents the exhaust gas from flowing into the seal member, prevents abnormal noise due to vortex flow, and prevents pressure loss to the engine. Become.

[0010]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the joint according to the present invention will be described below in detail with reference to the drawings. In FIG. 1, 25 and 27 are 0.
A thin metal exhaust pipe formed with a wall thickness of 6 to 0.8 mm, 29 is a bellows-shaped metal seal member fitted and arranged in the exhaust pipes 25 and 27, and connecting the exhaust pipes 25 and 27. The end portions 25a and 27a are flared in a trumpet shape along the shape of the curved portion 29a at the outermost end of the seal member 29. The curved portions 29a are in pressure contact with the inner circumferences of the connection end portions 25a and 27a, respectively.

The seal member 29 is a thin metal tube made of SUS304 and having a thickness of 0.6 mm formed into a bellows shape, and two peaks 29b having a height of 5 to 8 mm are 8 mm.
The cylindrical portions 29c and 29d provided at both ends thereof have outer diameters that can be press-fitted into the exhaust pipes 25 and 27.

The thickness of the sealing member 29 is 0.
A cylindrical metal seal pressing member 31 of 6 to 0.8 mm is arranged on the same axis as the exhaust pipes 25 and 27, and one cylindrical portion 29c of the seal member 29 is spot-welded to the outer circumference on one end side thereof. Has been done. The other tubular portion 29d of the seal member 29 is a free end with respect to the seal pressing member 31, and when connecting the exhaust pipes 25 and 27 by the plate flanges 33 and 35, which will be described later, the tubular portion 29d. 29d
Is sandwiched between the exhaust pipe 27 and the seal pressing member 31 and slides on the outer periphery of the seal pressing member 31, and the entire seal member 29 contracts due to the pressing force of both the exhaust pipes 25 and 27. The curved portion 29a at the end causes the restoring force generated from the shape and material of the sealing member 29 itself to cause the respective connecting end portions 25a, 2a.
It is adapted to come into pressure contact with the inner periphery of 7a.

On the other hand, in FIG. 1, 33 and 35 are exhaust pipes 25 and
A pair of plate flanges externally fitted to the outer circumferences of the connection end portions 25a, 27a of the two plate flanges 33, 35.
Is a metal plate material having a thickness of 2.3 mm, which is press-formed along the outer shape of the connection ends 25a and 27a so that it can be fitted onto the outer circumference of the connection ends 25a and 27a of the exhaust pipes 25 and 27. An exhaust pipe insertion hole 37 is formed in the center, and flat bolt fastening portions 39 and 41 are formed around the exhaust pipe insertion hole 37.

Then, the plate flanges 33 and 35, which are externally fitted to the connection end portions 25a and 27a and are opposed to each other, are fastened with the bolts 43 and the nuts 45, so that the sealing force of the seal member 29 is exerted as described above. The tubular portion 29d is held between the exhaust pipe 27 and the seal pressing member 31 and slides on the outer periphery of the seal pressing member 31, and the entire seal member 29 is degenerated by the pressing force of both the exhaust pipes 25 and 27. ,
The outermost curved portion 29a is brought into pressure contact with the inner circumference of each of the connecting end portions 25a and 27a by the restoring force of the seal member 29.

In addition, in the figure, 47 is a bolt tightening portion 39,
41 is a bolt insertion hole, 49 is a plate flange 3
3 and 35 are reinforcing flange portions formed by bending the outer peripheral edge portions into a substantially L-shaped cross section.

Since the joints of the exhaust pipes 25 and 27 according to this embodiment are constructed in this way, in order to connect the exhaust pipes 25 and 27, first, from the other side of the exhaust pipes 25 and 27, respectively. The plate flanges 33 and 35 are inserted to connect the exhaust pipes 25 and 27 to the connecting end portions 25a and 27a as shown in FIG.
The plate flanges 33 and 35 are externally fitted around the outer periphery of the.

Next, one end of the seal pressing member 31 obtained by spot-welding the tubular portion 29c of the seal member 29 is fitted into the exhaust pipe 25 from the connection end 25a side, and the other exhaust pipe 27 is sealed. The pressing member 31 is press-fitted so that the tubular portion 29d of the seal member 29 is held between the seal pressing member 31 and the exhaust pipe 27.

Then, if the plate flanges 33 and 35 fitted on the respective connection ends 25a and 27a are tightened with the bolts 43 and the nuts 45, as described above, the tightening force causes
The tubular portion 29d of the seal member 29 is sandwiched between the exhaust pipe 27 and the seal pressing member 31 and slides on the outer periphery of the seal pressing member 31, and the entire seal member 29 covers both the exhaust pipes 2.
The outermost curved portion 2 is contracted by the pressing force of 5, 27.
9a is pressed against the inner circumference of each of the connection ends 25a and 27a to ensure the sealing property between the curved portion 29a and the connection ends 25a and 27a.

When the plate flanges 33 and 35 are bolted in this manner, the plate flanges 33 and 35 connect the tubular portions 29c and 29d of the seal member 29 between the seal pressing member 31 and the exhaust pipes 25 and 27. Tighten tightly and secure the sealing property between them.

The exhaust pipes 25, 27 are driven by the running of the vehicle.
Even if the vibration occurs, the bellows-shaped seal member 29 absorbs the stress applied to the seal member 29 by its curved portion 29a pressingly contacting the inner circumference of each connecting end portion 25a, 27a and deforming freely. The seal pressing member 31 smoothly causes the exhaust gas in the exhaust pipes 25 and 27 to flow down, prevents the exhaust gas from flowing into the seal member 29, and prevents the abnormal noise from being generated by the vortex flow in the mountain portion 29b. Prevent pressure loss to.

As described above, according to this embodiment, the exhaust pipe 2
Since these can be connected to each other without welding to 5, 5 and 27, the exhaust pipes 25 and 27 can be thinned,
In addition, the risk of intergranular corrosion due to welding is eliminated, and cost reduction and vehicle weight reduction are possible.

Further, according to this embodiment, it is not necessary to improve the processing accuracy of the connecting end portions 25a, 27a of the exhaust pipes 25, 27 as in the embodiment shown in FIG. The curved portion 29a is pressed against the inner circumferences of the connection ends 37a and 39a by the restoring force caused by the contraction of the seal member 29, and the plate flanges 33 and 35 cause the cylindrical portions 29c and 29d of the seal member 29 to seal against the seal pressing member 31. And exhaust pipe 2
5 and 27 are firmly tightened to secure the sealing property against exhaust gas leakage, and the curved portion 29a of the seal member 29 is pressed against the inner circumference of the connection end portions 37a and 39a against vibration during traveling. Since the seal member 29 is freely deformed to absorb the stress applied to the seal member 29, no crack is generated in the seal member 29, and therefore, exhaust gas leakage is surely prevented for a long period of time. It becomes possible.

Further, according to the present embodiment, since the reassembling is easy, only the replacement of the seal member 29 which is deformed at the time of tightening is required and the serviceability is excellent. Although the seal member 29 is made of SUS304 in the above embodiment,
The material is not limited to SUS304, and steel materials having heat resistance and spring properties can be widely used.

The sealing member 29 has a one-layer structure in which a thin metal tube having a wall thickness of 0.6 mm is formed into a bellows shape, but a thin metal tube having a wall thickness of 0.3 mm is formed into a bellows shape to form two layers. The structure may be used, and even with this structure, the intended purpose can be achieved, as in the above-described embodiment.

[0025]

As described above, according to the joint of the present invention, the exhaust pipe can be connected without any welding at the time of connecting the exhaust pipe, so that the exhaust pipe can be made thin. In addition, there is no risk of intergranular corrosion due to welding, cost reduction, and vehicle weight reduction are possible.

Further, according to the present invention, the curved portion is brought into pressure contact with the inner circumference of the connecting end portion by the restoring force caused by the contraction of the seal member due to the pressing force of the exhaust pipe, and the end portion of the seal member is sealed by the plate flange. Tightly tightens between the holding member and the exhaust pipe to ensure sealing performance against exhaust gas leakage, and the curved portion of the sealing member can be pressed against the inner circumference of the connection end against vibration during traveling. Since the seal member is deformed to absorb the stress applied to the seal member, according to the present invention, the seal member is not cracked, so that the exhaust gas can be reliably prevented from leaking for a long period of time. Is possible and
Further, it is not necessary to enhance the processing accuracy of the connecting end portion of the exhaust pipe to be connected as in the conventional case.

Furthermore, according to the present invention, since the recombination is easy, it is possible to replace only the seal member that is deformed at the time of tightening, and there is an advantage of excellent serviceability.

[Brief description of drawings]

FIG. 1 is a cross-sectional view of an exhaust pipe joint according to an embodiment of the present invention.

FIG. 2 is a sectional view showing a method of connecting exhaust pipes according to an embodiment of the present invention.

FIG. 3 is a side view of a conventional exhaust pipe joint.

FIG. 4 is a side view of another conventional exhaust pipe joint.

[Explanation of symbols]

 25, 27 Exhaust pipe 25a, 27a Connection end 29 Seal member 29a Curved part 29c, 29d Cylindrical part 31 Seal pressing member 33, 35 Plate flange

Claims (1)

[Claims] 1. Exhaust pipes (25, 27) each connecting end of which is expanded in a trumpet shape, and both connecting ends (25a, 27a) of the exhaust pipes (25, 27).
A cylindrical metal seal pressing member (31) mounted on the same axis as both the exhaust pipes (25, 27), and one end side of which is welded to the outer periphery of the seal pressing member (31), 25, 27) and a bellows-shaped metallic seal member (29) that is contracted by the pressing force and is pressed against the inner circumferences of both connection ends (25a, 27a), and the outer shape of the connection ends (25a, 27a). Molded along,
An exhaust pipe joint, comprising: a pair of plate flanges (33, 35) externally fitted to the outer periphery of each connection end (25a, 27a) and bolted.