JP3857767B2 - Double pipe type exhaust manifold - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to an exhaust manifold attached to a cylinder head of an automobile engine, and more particularly, to a double-tube exhaust manifold having a double structure of an outer tube and an inner tube.
[0002]
[Prior art]
Recently, catalytic converters for purifying harmful gases in exhaust gas have been attached to the exhaust system of automobiles, so that the catalytic activity of this catalytic converter does not decrease even immediately after engine startup. A double-pipe type exhaust manifold having a heat insulation space for preventing a decrease in exhaust gas temperature has been developed.
[0003]
FIG. 4 shows an example of such a double-pipe type exhaust manifold. A long outer tube 1 and an outer tube 3 are arranged in series in the axial length direction, and are formed in the outer tube 1. The opening 1a for connection and the opening 3a for connection formed in the outer tube | pipe 3 are arrange | positioned facing each other.
Further, the outer tube 1 and the outer tube 3 are formed with two protruding portions 1b and two protruding portions 3b, respectively, at a predetermined interval.
[0004]
Cylinder head mounting flanges 5 are welded to the open ends of the protrusions 1b and 3b, respectively.
Furthermore, a flange 7 for attaching the catalytic converter is welded to an opening end formed on the opposite side of the connection opening 3 a of the outer tube 3.
As shown in FIG. 5, the inner diameter of the connection opening 1a of the outer tube 1 is formed to be substantially the same as the outer diameter of the outer tube 3, and the outer tube 3 is formed on the inner peripheral side of the connection opening 1a. The connection opening 3a is inserted.
[0005]
And the front-end | tip of the opening part 1a for connection and the outer periphery of the outer tube | pipe 3 are welded 9, and the outer tube | pipe 1 and the outer tube | pipe 3 are being fixed.
Moreover, the 1st and 2nd inner tubes 13 and 15 are arrange | positioned through the space 11a for heat insulation, and the space 11b for heat insulation inside the outer tube | pipe 1 and the outer tube | pipe 3. As shown in FIG.
A connection opening 15a having an inner diameter substantially the same as the outer diameter of the first inner tube 13 is formed on the second inner tube 15 on the first inner tube 13 side, and this connection opening 15a. A connection opening 13 a formed in the inner tube 13 is inserted into the inner tube 13.
[0006]
An annular cushioning material 17 is disposed on the outer periphery of the connection opening 15a of the second inner tube 15, and the buffering material 17 is spot welded 19 to the outer periphery of the connection opening 15a.
The outer periphery of the cushioning material 17 is brought into close contact with the inner periphery of the connection opening 3 a of the outer tube 3, and the first and second inner tubes 13, 15 are arranged at predetermined positions inside the outer tube 1 and the outer tube 3. Regulated in position.
[0007]
In the above-described double-pipe type exhaust manifold, when the first and second inner pipes 13 and 15 are thermally expanded or contracted in the axial direction by starting and stopping the engine, a predetermined position is set by the buffer material 17. The connection opening 13a of the first inner tube 13 and the connection opening 15a of the second inner tube 15 move in close contact with each other, and the first and second inner tubes 13 The local thermal stress generated in the tubes 13 and 15 is relieved.
[0008]
[Problems to be solved by the invention]
However, in such a conventional double pipe type exhaust manifold, the first and second inner pipes 13 and 15 tightly contact the outer periphery of the connection opening 13a and the outer periphery of the connection opening 15a. In this state, since thermal expansion or thermal contraction occurs, there has been a problem that abnormal noise such as rubbing noise is generated during the thermal expansion or thermal contraction.
[0009]
Further, when the first and second inner pipes 13 and 15 are thermally expanded or contracted in the circumferential direction, a gap is formed between the outer periphery of the connection opening 13a and the inner periphery of the connection opening 15a. When this occurs, there is a problem that chatter noise is generated due to vibration such as exhaust pulsation.
The present invention has been made to solve such conventional problems, and it is possible to prevent the generation of abnormal noise such as rubbing noise and chatter noise due to thermal expansion or contraction of the inner tube by a simple means. An object is to provide a double pipe type exhaust manifold.
[0010]
[Means for Solving the Problems]
The double pipe type exhaust manifold according to claim 1 includes an outer pipe, a first inner pipe disposed on one inner side in the axial length direction of the outer pipe, and a second inner pipe disposed on the other inner side. And an opening end formed on the second inner tube side of the first inner tube is inserted into an opening end formed on the first inner tube side of the second inner tube. In the double-pipe type exhaust manifold, an annular cushioning material that covers the open end of the second inner tube and that is continuous from the inner periphery to the outer periphery of the second inner tube is disposed. the close contact with the outer periphery of the first inner tube, the Ri and the outer periphery of the cushioning material name in close contact with the inner periphery of the outer tube, the outer tube is divided into cross-sectional direction of the outer tube, the divided The end is welded .
[0011]
The double pipe type exhaust manifold according to claim 2 is the double pipe type exhaust manifold according to claim 1 , wherein the second inner pipe is arranged closer to the exhaust gas outlet side than the first inner pipe. It is characterized by.
[0012]
The double-pipe type exhaust manifold of claim 3 is the double-pipe type exhaust manifold of claim 1 or claim 2 , wherein the cushioning material is made of a net member knitted with a thin metal wire, and the cushioning material and the first The second inner pipe is spot-welded.
[0013]
(Function)
In the double-pipe type exhaust manifold according to claim 1, an annular cushioning material continuing from the inner periphery to the outer periphery is disposed at the opening end of the second inner tube, and the inner periphery of the cushioning material is the first inner tube. The outer periphery of the cushioning material is in close contact with the inner periphery of the outer tube.
[0014]
The start and stop of the engine prevents the generation of rubbing noise when the first and second inner pipes thermally expand or contract in the axial direction.
Further, when the first and second inner pipes are thermally expanded or contracted in the circumferential direction by starting and stopping the engine, the outer periphery of the first inner pipe and the second inner pipe are A gap is prevented from occurring between the inner periphery and chatter noise due to vibrations such as exhaust pulsation.
[0015]
Furthermore, for easy handling, the outer tube is divided along the cross section and welded at this divided end.
In the double-pipe type exhaust manifold according to claim 2 , the second inner pipe is disposed closer to the exhaust gas outlet than the first inner pipe, and the exhaust end of the first inner pipe extending toward the exhaust direction causes the exhaust gas to be exhausted. Blowing into the cushioning material is prevented.
[0016]
And the penetration | invasion to the space for heat insulation of waste gas is blocked | prevented and the fall of waste gas temperature is prevented.
In the double pipe type exhaust manifold according to the third aspect, the buffer material formed by the net member knitted with the fine metal wire is spot-welded to the second inner pipe.
The buffer material can easily absorb thermal expansion or contraction of the first and second inner pipes in the axial length direction, and prevent the buffer material from falling off from the second inner pipe. .
[0017]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.
1 and 2 show an embodiment (corresponding to claims 1 to 3 ) of a double-pipe type exhaust manifold of the present invention, and FIG. 1 shows the details of the main part of FIG. ing.
[0018]
In FIG. 2, reference numerals 21 and 23 are long outer tubes made of, for example, stainless steel having a thickness of 1.5 mm.
The outer tube 21 and the outer tube 23 are arranged in series in the axial direction, and a connection opening 21a formed in the outer tube 21 and a connection opening 23a formed in the outer tube 23 face each other. Has been placed.
[0019]
In addition, the outer tube 21 and the outer tube 23 are formed with two circular projecting portions 21b and two projecting portions 23b, respectively, at predetermined intervals.
Cylinder head mounting flanges 25 are welded to the open ends of the protrusions 21b and 23b, respectively.
Further, a flange 27 for attaching the catalytic converter is welded to the opening end of the outer tube 23 opposite to the connection opening 23a.
[0020]
Further, as shown in FIG. 1, the inner diameter of the connection opening 21a of the outer tube 21 is formed to be substantially the same as the outer diameter of the outer tube 23, and the outer tube 23 is formed on the inner peripheral side of the connection opening 21a. The connection opening 23a is inserted.
And the front-end | tip of the opening part 21a for a connection and the outer periphery of the outer tube | pipe 23 are welded 29, and the outer tube | pipe 21 and the outer tube | pipe 23 are being fixed.
[0021]
Furthermore, inside the outer tube 21 and the outer tube 23, the first inner tube 33 and the second tube made of, for example, stainless steel having a thickness of 0.5 mm are provided via the heat insulating space 31a and the heat insulating space 31b. The inner pipe 35 is arranged with the second inner pipe 35 positioned on the exhaust gas outlet side from the first inner pipe 33.
A connection opening 35a having an inner diameter larger than the outer diameter of the first inner tube 33 is formed on the first inner tube 33 side of the second inner tube 35. The connection opening 35a has a first opening. A connection opening 33a formed in the inner pipe 33 is inserted.
[0022]
Furthermore, an annular cushioning material 37 that is continuous from the inner periphery to the outer periphery of the connection opening 35a is disposed at the opening end of the connection opening 35a of the second inner pipe 35. Spot welding 39 is performed on the outer periphery and inner periphery of the opening 35 a and is fixed to the second inner pipe 35.
As this buffer material 37, for example, a stainless steel thin wire generally called a SUS material, which is knitted into a knitted shape, is appropriately bent to have elasticity.
[0023]
Further, the inner periphery of the buffer material 37 is elastically adhered to the outer periphery of the second inner tube 35, and the outer periphery of the buffer material 37 is elastically adhered to the inner periphery of the outer tube 23.
The first and second inner tubes 33 and 35 are regulated by the buffer material 37 at predetermined positions inside the outer tube 21 and the outer tube 23.
In the above-described double-pipe type exhaust manifold, when the first and second inner pipes 33 and 35 are thermally expanded or contracted in the axial direction by starting and stopping the engine, a predetermined position is set by the buffer material 37. The connection opening 33a of the first inner tube 33 and the connection opening 35a of the second inner tube 35 are freely moved via the cushioning material 37 while being restricted by the first and second inner tubes 33. The local thermal stress of the inner pipes 33 and 35 is relieved.
[0024]
When the first and second inner pipes 33 and 35 are thermally expanded or contracted in the circumferential direction, the buffer material 37 is deformed following the thermal expansion or contraction, and the first inner tube 33 or 35 is deformed. It is possible to prevent a gap from being generated between the outer periphery of the connection opening 33 a of the tube 33 and the inner periphery of the connection opening 35 a of the second inner tube 35.
Then, the connection opening 33a of the first inner pipe 33 extending in the exhaust direction E of the exhaust gas prevents the exhaust gas from being blown into the buffer material 37 and prevents the exhaust gas temperature from decreasing.
[0025]
Further, the heat insulating action of the heat insulating spaces 31a and 31b prevents the exhaust gas temperature from decreasing, and the exhaust gas is purified without reducing the catalytic activity even when the engine is started when the exhaust passage is cold.
In the double-pipe type exhaust manifold configured as described above, an annular cushioning material 37 continuous from the inner periphery to the outer periphery of the second inner tube 35 is disposed in the connection opening 35 a of the second inner tube 35. Since the inner periphery of the cushioning material 37 is in close contact with the outer periphery of the connection opening 33a of the first inner pipe 33, the first and second inner pipes 33 and 35 are not rubbed with each other. Thermal expansion or contraction can be freely performed in the longitudinal direction, and generation of abnormal noise such as rubbing noise can be prevented with simple means.
[0026]
Further, since the inner periphery of the buffer material 37 is in close contact with the outer periphery of the connection opening 33a of the first inner tube 33, the first and second inner tubes 33 and 35 are thermally expanded or thermally expanded in the circumferential direction. When contracted, the cushioning material 37 can follow the thermal expansion or contraction and thus deform.
Accordingly, it is possible to prevent a gap from being generated between the outer periphery of the connection opening 33a and the inner periphery of the connection opening 35a, and to prevent the occurrence of chatter noise due to vibration such as exhaust pulsation. Can do.
[0027]
Further, since the outer tube 21 and the outer tube 23 are divided and the outer tube 21 and the outer tube 23 are welded 29, the manufacture and handling of the outer tubes 21 and 23 can be facilitated. Further, since the first inner pipe 33 is disposed on the exhaust gas outlet side from the second inner pipe 35, the exhaust gas buffering material is provided by the connection opening 33a of the first inner pipe 33 extending in the exhaust direction E. Blowing into 37 can be prevented, and a reduction in exhaust gas temperature can be prevented.
[0028]
Furthermore, since the cushioning material 37 is formed by a net member knitted with fine metal wires, the thermal expansion or contraction in the axial length direction of the first and second inner tubes 33 and 35 can be easily absorbed.
Further, since the buffer material 37 is spot welded 39 to the first inner pipe 33, the buffer material 37 can be prevented from falling off from the connection opening 35a of the second inner pipe 35.
[0029]
In the above-described embodiment, the outer tube 21 and the outer tube 23 are arranged in series in the axial direction, and the connection opening 23a of the outer tube 23 is inserted into the connection opening 21a of the outer tube 21. Although an example has been described, the present invention is not limited to such an embodiment. For example, as shown in FIG. 41 may be used.
[0030]
In the above-described embodiment, the example in which the thickness of the outer tube 21 is 1.5 mm and the thickness of the first and second inner tubes 33 and 35 is 0.5 mm has been described. For example, the thickness of the outer tube 21 may be 1.8 mm, and the thickness of the first and second inner tubes 33 and 35 may be 0.8 mm.
[0031]
In the above-described embodiment, the example in which the outer pipes 21 and 23 are formed of stainless steel has been described. However, the present invention is not limited to such an embodiment. For example, the outer pipes 21 and 23 are formed of cast iron or aluminum alloy. Also good.
Further, in the above-described embodiment, the example in which the first and second inner pipes 33 and 35 are formed of stainless steel has been described. However, the present invention is not limited to such an embodiment, for example, an aluminum alloy or the like. May be formed.
[0032]
【The invention's effect】
As described above, in the double-pipe type exhaust manifold according to claim 1, an annular cushioning material that is continuous from the inner periphery to the outer periphery of the second inner tube is disposed at the opening end of the second inner tube. Since the inner periphery of the cushioning material is in close contact with the outer periphery of the first inner tube, the first and second inner tubes can be freely thermally expanded or contracted in the axial direction without rubbing each other, Occurrence of abnormal noise such as rubbing noise can be prevented with simple means.
[0033]
Further, since the inner periphery of the buffer material is in close contact with the outer periphery of the first inner tube, when the first and second inner tubes are thermally expanded or contracted in the circumferential direction, the buffer material is heated. It can be deformed following expansion or thermal contraction.
Therefore, it is possible to prevent a gap from being generated between the outer periphery of the first inner tube and the inner periphery of the second inner tube, and to prevent chatter noise due to vibration such as exhaust pulsation. .
[0034]
Furthermore, since the outer tube is divided along the cross section, the outer tube can be easily manufactured and handled.
In the double-pipe type exhaust manifold according to claim 2 , since the first inner pipe is arranged on the exhaust gas outlet side from the second inner pipe, the exhaust end of the first inner pipe extending in the exhaust direction is exhausted. Can be prevented from blowing into the buffer material, and the exhaust gas temperature can be prevented from lowering.
[0035]
In the double-pipe type exhaust manifold according to claim 3, since the buffer material 37 is formed by a net member knitted with a fine metal wire, the first and second inner pipes 33 and 35 are thermally expanded or contracted in the axial length direction. Can be easily absorbed.
Further, since the buffer material 37 is spot welded 39 to the first inner pipe 33, the buffer material 37 can be prevented from falling off from the connection opening 35a of the second inner pipe 35.
[Brief description of the drawings]
FIG. 1 is a cross-sectional view showing details of a main part of FIG.
FIG. 2 is a side view showing an embodiment of the double pipe type exhaust manifold of the present invention.
FIG. 3 is a cross-sectional view showing an example in which an outer tube is formed of a single member.
FIG. 4 is a side view showing a conventional double pipe type exhaust manifold.
FIG. 5 is a cross-sectional view showing details of a main part of a conventional double pipe type exhaust manifold.
[Explanation of symbols]
21, 23, 41 Outer tube 29 Welding 33 First inner tube 33a Connection opening (opening end)
35 Second inner pipe 35a Connection opening (open end)
37 Buffer material 39 Spot welding

Claims (3)

An outer tube (21, 23, 41), a first inner tube (33) disposed inside one of the outer tubes (21, 23, 41) in the axial length direction, and the other inner tube A second inner pipe (35), and an opening end (35a) formed on the side of the first inner pipe (33) of the second inner pipe (35), the first inner pipe ( 33) In the double pipe type exhaust manifold formed by inserting an open end (33a) formed on the second inner pipe (35) side of
An annular cushioning material (37) continuous from the inner periphery to the outer periphery of the second inner tube (35) is disposed so as to cover the open end (35a) of the second inner tube (35). (37) the inner circumference of the close contact with the outer periphery of the first inner tube (33), Ri greens in close contact with the inner periphery of the outer tube the outer periphery of the cushioning material (37) (21,23,41) ,
A double-pipe type exhaust manifold, wherein the outer pipe (21, 23) is divided in the cross-sectional direction of the outer pipe (21, 23), and the divided end is welded (29) . The double pipe type exhaust manifold according to claim 1,
The double pipe type exhaust manifold is characterized in that the second inner pipe (35) is arranged on the exhaust gas outlet side from the first inner pipe (33) . The double pipe type exhaust manifold according to claim 1 or 2 ,
The buffer material (37) is made of a net member knitted with fine metal wires, and the buffer material (37) and the second inner pipe (35) are spot-welded (39). Double pipe type exhaust manifold.

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