JP2001355435A - Metal carrier for catalytic converter - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a metal carrier for a catalytic converter prevented from the deformation and crack initiation of cell shape by reinforcing cores. SOLUTION: This metal carrier comprises an outer cylinder 21; the cores 23, 25, 27 disposed in the outer cylinder; a holding shaft 29 piercing the center of the cores and formed with an exhaust gas passage 31 opened on the exhaust gas inflow side and closed on the other end side, and further having an end plate 35 formed abutting on a downstream end face 27a of the core 27, and exhaust gas outflow holes 41, 33 formed in a peripheral wall positioned at space parts 37, 39; holding rings 45 fitted to the outer periphery of the holding shaft 29 in correspondence with the exhaust gas outflow holes 41, 33, held by the cores 23, 25, 27 and formed with exhaust gas outflow holes 47; a ring spacer 49 having the same diameter as the inner diameter of the outer cylinder 21 and held by the cores 23, 25, 27; and a pressing member fitted to the exhaust gas inflow side end part of the holding shaft 29.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a metal carrier for a catalytic converter mounted on an exhaust system of an internal combustion engine.

[0002]

2. Description of the Related Art Conventionally, a catalytic converter for purifying exhaust gas has been mounted in an exhaust system of an internal combustion engine, and as a catalyst carrier used for this, a Fe—Cr—Al ferrite stainless steel foil material (20Cr-5Al) has recently been used. -La-Fe) and the like are widely used.

Conventionally, as a method of manufacturing this metal carrier, a band-shaped corrugated sheet made of a thin metal plate and a flat plate are alternately stacked, and these are wound in multiple layers to form a circular cross section or an elliptical cross section (cross section racing track). After forming a core (honeycomb body) of a shape, a Ni low foil material is wound around the rear side (exhaust gas outflow side) of the core or the outer periphery of the central portion thereof, and these are pressed into a metal outer cylinder to form a vacuum. A method of manufacturing a metal carrier in which a corrugated plate and a flat plate are diffusion-bonded by heat treatment in a state and the outer cylinder and the core are brazed and bonded is known.

By the way, recently, in order to promote the heat conduction of the core and to increase the catalytic activity at the time of cold start,
As shown in FIG. 4, a metal carrier 7 in which one conventional core mounted in an outer cylinder is cut into a plurality of cores 1 and 3 and these are arranged in an outer cylinder 5 at predetermined intervals. This is known (see JP-A-11-2118). Then, as shown in FIG. 4 to FIG.
In order to improve the heat resistance and durability of the central part of the pipe 3, one pipe 11 whose exhaust gas outflow end 9 is closed is connected to the cores 1, 3.
Of the pipe 11 located in the space 13 between the cores 1 and 3 (portion A in FIG. 4).
An exhaust gas guide hole 17 having a guide piece 15 for guiding the exhaust gas G from the inside of the pipe 11 to the space 13 is provided to improve purification performance by promoting agitation of the exhaust gas.

[0005]

The core expands due to the heat of oxidation of the catalyst and repeats expansion and contraction by a heat cycle. However, the cores 1 and 3 have an axial dimension smaller than that of the conventional core. Due to the short length, the strength of the carrier was reduced, and there was a possibility that the cell shape was deformed or cracked due to expansion and contraction due to a heat cycle.

In particular, the core at the forefront located on the upstream side of the exhaust gas has a smaller axial length and a smaller volume than the core on the downstream side for the purpose of reducing the heat capacity and rapidly raising the temperature. Therefore, deformation and cracking of the cell shape are most likely to occur. Recently, for the purpose of reducing costs and reducing the heat capacity of the cores 1 and 3 to further improve heat conductivity, the cores 1 and 2 are made of thin metal plates having a thickness of 20 to 30 μm. However, it has been pointed out that the use of such a thin metal thin plate further reduces the strength of the cores 1 and 3.

The metal carrier 7 disclosed in Japanese Patent Application Laid-Open No. 11-2118 does not prevent the core from deforming in the flow direction of exhaust gas. In this case, the cores 1 and 3 are displaced in the flow direction of the exhaust gas, so that the cell shape is deformed or cracks occur. The present invention has been devised in view of such circumstances, and as described above, a metal carrier in which a plurality of cores are arranged at predetermined intervals in an outer cylinder is improved, and the cell shape is enhanced by reinforcing the cores. An object of the present invention is to provide a metal carrier for a catalytic converter in which deformation and cracks are prevented from occurring.

[0008]

In order to achieve the above object, the metal carrier of the catalytic converter according to the first aspect of the present invention is obtained by winding a metal outer cylinder, a thin metal corrugated plate and a flat plate in multiple layers. A plurality of cores that are formed and disposed at predetermined intervals in the outer cylinder, and an exhaust gas flow passage that penetrates the center of each core and is open on the exhaust gas inflow side and closed on the other end side, are formed, An end plate abutting on the downstream end surface of the last core is formed, and on a peripheral wall located in a space between the cores,
A holding shaft in which a plurality of exhaust gas outlet holes communicating with the exhaust gas passage are formed, and an outer periphery of the holding shaft corresponding to the exhaust gas outlet hole is attached, and is sandwiched by each core to form a plurality of exhaust gas outlet holes in a peripheral wall. The holding ring, which is molded to the same size as the inner diameter of the outer cylinder, is mounted on the exhaust gas inflow side end of the holding shaft and the ring spacer sandwiched by the cores, and is attached to the upstream end surface of the forefront core. And a pressing member to be pressed against.

The invention according to claim 2 is the invention according to claim 1.
In the metal carrier of the catalytic converter according to the present invention, the exhaust gas outflow hole of one of the holding shaft and the holding ring is formed in the shape of a long hole in the circumferential direction. In the metal carrier of the catalytic converter according to the first or second aspect, the pressing member is a tightening nut screwed to the end of the holding shaft on the exhaust gas inflow side.

(Function) When exhaust gas flows into the catalytic converter equipped with the metal carrier according to each claim, the exhaust gas passes through the core, is purified by the catalyst, and flows into the exhaust gas passage of the holding shaft. The exhaust gas thus discharged is discharged into the space from the exhaust gas outflow hole, thereby promoting the agitation of the exhaust gas in the space.

[0011] Then, heat is conducted from the core located at the forefront to the core on the exhaust gas downstream side, and each core expands. Then, expansion and contraction are repeated by a heat cycle.
A ring spacer holds the outer peripheral edge of the core, and a retaining ring and an end plate hold the central peripheral edge of the core to prevent the core from shifting in the exhaust gas flow direction. Also,
According to the second aspect of the invention, when the holding ring is attached to the holding shaft, the positioning of the holding shaft and the holding ring with respect to the exhaust gas outflow holes can be easily performed.

According to the third aspect of the present invention, if the tightening nut is tightened in manufacturing the metal carrier, the core, the holding ring, and the ring spacer are firmly held between the tightening nut and the end plate. It will be.

[0013]

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

1 to 3 show a metal carrier of a catalytic converter according to one embodiment of the present invention. In FIG. 1, reference numeral 21 denotes a cylindrical outer cylinder formed of metal.
In the outer cylinder 21, three cores 23, 25, and 27 are arranged in the axial direction at the same interval H. As in the prior art, the cores 23, 25, and 27 are formed by alternately stacking strip-shaped corrugated sheets made of a thin metal plate and flat plates, winding these multiple times to form one core having a circular cross section, and then forming the core by three. The cores 23 and 25 located on the upstream side of the exhaust gas are located at the rearmost part in order to reduce the heat capacity and quickly raise the temperature. The length in the axial direction is shorter than that of the core 27 and the volume is smaller.

A metal holding shaft 29 having an outer diameter of 6 mm penetrates through the center of the cores 23, 25 and 27. As shown in FIGS. 1 and 2, the holding shaft 29 is open on the exhaust gas inflow side, and an exhaust gas flow passage 31 is provided inside the exhaust shaft 33, which will be described later. Is a hollow pipe, and a solid pipe at the penetrating portion of the core 27 shuts off the exhaust gas flow at the core 27.

At the end of the holding shaft 29, a circular end plate 35 which is in contact with the downstream end surface 27a of the last core 27 is integrally formed. As described above, in the present embodiment, the holding shaft 29 is a hollow tube up to the core 27 and the exhaust gas flow in the core 27 is closed as a solid tube in the penetrating portion of the core 27. May be a hollow tube, and the end may be closed by the end plate 35.

The peripheral wall of the holding shaft 29 located in the space 37 between the cores 23 and 25 and the peripheral wall of the holding shaft 29 located in the space 39 between the cores 25 and 27 are each provided with an elongated exhaust gas. Two outflow holes 41 and 33 are provided in the circumferential direction, and the exhaust gas G flowing down the exhaust gas flow passage 31 flows out of each of the exhaust gas outflow holes 41 and 33 to the outside. A tightening nut 43 pressed against the upstream end surface 23a of the core 23 is screwed to a screw portion 29a provided on the outer periphery of the exhaust gas inflow end of the holding shaft 29.

As shown in FIG. 1 and FIG.
A metal holding ring 45 is fixed to the outer periphery of the nozzle 9 in correspondence with the exhaust gas outflow holes 41 and 33, and a plurality of circular exhaust gas outflow holes 47 are provided in the peripheral wall.
Thus, the holding ring 45 is formed at the same height as the interval H between the cores 23, 25, 27, and the cores 23, 25, 2
7, the holding ring 45 has a wall thickness of 1.5 to 2 m in order to minimize a decrease in the area of the upstream end surfaces 25a and 27b of the cores 25 and 27.
m and a diameter of 10 mm. Similarly, in order to minimize a decrease in the area of the upstream end surface 23a of the core 23, the above-described tightening nut 43 has the same outer dimensions as the holding ring 45.

Further, between the core 23 and the core 25, and
Between the core 25 and the core 27, a metal ring spacer 49 having the same outer diameter as the inner diameter of the outer cylinder 21 and having a thickness of about 1.5 to 2 mm is interposed. Are formed at the same height as the holding ring 45, and are sandwiched between the outer peripheral edges of the cores 23, 25, and 27.

Then, by tightening the above-described tightening nut 45, the tightening nut 45 and the end plate 35 are tightened.
Between the cores 23, 25, and 27, the holding ring 45, and the ring spacer 49.
3, 25, 27 and the ring spacer 49, respectively,
It is brazed to 1. The metal carrier 51 according to the present embodiment is configured as described above,
Is manufactured by the following manufacturing method.

As described above, first, a band-shaped corrugated sheet made of a thin metal plate and a flat plate are alternately stacked, and these are wound in a multiplex manner to form one core having a circular cross section, and then this is cut into three. The cores 23, 25, and 27 are formed by slicing. The corrugated plate and the flat plate are appropriately spot-welded.

Then, as shown in FIG. 3, the holding shaft 29 is passed through the center of the core 27 from the downstream end surface 27a of the core 27, and the end plate 35 is attached to the downstream end surface 27a of the core 27.
Abut. Next, the holding ring 45 is inserted into the holding shaft 29, and the holding ring 45 is connected to the upstream end surface 2 of the core 27.
7b, the exhaust gas outlet holes 47, 33 are opposed to each other, and then the ring spacer 49, the core 25, the holding ring 4
5, the ring spacer 49 and the core 23 are inserted into the holding shaft 29 in this order, and the screw nut 29a of the holding shaft 29 is
3 is screwed.

Each of the above-described holding rings 45 is
It is preferable to attach to the holding shaft 29 via a paste-like brazing material. In this assembly, the exhaust gas outflow holes 33 and 41 of the holding shaft 29 are formed in a long hole shape.
Positioning with the exhaust gas outflow hole 47 is easy. Then, the tightening nut 43 is tightened and the end plate 35 is tightened.
After firmly holding the cores 23, 25, 27, the holding ring 45, and the ring spacer 49 between the cores 23, 25, 27,
The raw foil material is wound around the outer circumferences of the ring spacers 5 and 27 and the outer circumference of the ring spacer 49. When these are pressed into the outer cylinder 21 and heat-treated in a vacuum state, the corrugated plates and the flat plates constituting the cores 23, 25 and 27 are diffusion-bonded, and the outer cylinder 21 and the core 2
3, 25, 27, the outer cylinder 21 and the ring spacer 49, and the holding shaft 29 and the holding ring 45 are respectively brazed and joined to produce the metal carrier 51. As in the conventional case, the catalyst is supported on the cores 23, 25, and 27. In the present embodiment, the catalyst is also supported on the exhaust gas flow passage 31, thereby improving the purification performance of the exhaust gas.

As described above, the holding ring 45 is preferably fixed to the holding shaft 29 via the brazing material. However, if the holding ring 45 is firmly fixed to the holding shaft 29 in a tight fit, the brazing is performed. Is unnecessary.

Further, in this embodiment, the fastening nut 43 is tightened so that the cores 23, 2
5 and 27, the holding ring 45 and the ring spacer 49 are firmly held, respectively. However, instead of the tightening nut 45, for example, a ring having the same diameter as the tightening nut 45 is welded or brazed to the holding shaft 29. The cores 23, 25, 27, the holding ring 45, and the ring spacer 49 may be firmly held between the plate 35.

The metal carrier 51 according to the present embodiment is configured as described above. When the exhaust gas G flows into the catalytic converter equipped with the metal carrier 51, the exhaust gas G passes through the cores 23, 25 and 27. The exhaust gas G flowing into the exhaust gas passage 31 of the holding shaft 29 is purified by the catalyst carried in the exhaust gas passage 31 and the exhaust gas outlet holes 47,
The gas is discharged from the spaces 41 and 33 into the spaces 37 and 39 to promote the agitation of the exhaust gas G in the spaces 37 and 39.

Then, heat is conducted from the core 23 located at the forefront to the cores 25, 27, and the cores 23, 25, 27
Expands and repeats expansion and contraction by the heat cycle. The ring spacer 49 holds the outer peripheral edge of the cores 23 and 25, and the holding ring 45 and the end plate 35 form the cores 23, 25 and 27. The central peripheral portion is held to prevent the cores 23, 25, 27 from shifting in the exhaust gas flow direction.

As described above, according to the present embodiment, the cores 23, 25, and which repeatedly expand and contract according to the heat cycle.
27 is firmly held by the holding ring 45, the ring spacer 49, and the end plate 35 to prevent displacement in the exhaust gas flow direction. Therefore, only the cores 1 and 3 are held by the outer cylinder 5 as shown in FIG. Compared with the conventional metal carrier 7, it has become possible to prevent cell shape deformation and cracking.

Further, according to the present embodiment, since the exhaust gas outflow holes 33 and 41 of the holding shaft 29 are formed in a long hole shape,
There is an advantage that the positioning of the exhaust gas outflow holes 33, 41, 47 becomes easy when the holding ring 45 is attached to the holding shaft 29. Furthermore, the central axis of the conventional metal carrier is 6 m.
The through-hole has a diameter of about m, and the catalyst is also provided in the through-hole. However, the fact is that the through-hole is a bypass for exhaust gas.

However, according to the present embodiment, the holding shaft 2
9. Since the holding ring 45 has the above-described structure, the exhaust gas can be prevented from being bypassed at the center shaft, and the exhaust gas can be passed through the holding shaft 29 to the respective intermediate portions 37,.
The mixture is supplied to the exhaust gas 39 to promote the agitation of the exhaust gas. For this reason, although the cell area is slightly reduced by attaching the holding ring 45 and the ring spacer 49, a reduction in the purification rate is prevented as much as possible.

As described above, in the present embodiment, the exhaust gas outflow holes 33 and 41 of the holding shaft 29 are formed into elongated holes to facilitate alignment with the exhaust gas outflow holes 47. Of course, as the hole shape, the exhaust gas outflow holes 33 and 41 may have a circular shape.

[0032]

As described above, according to the metal carrier according to each claim, a plurality of cores, which expand and contract repeatedly by a heat cycle, are formed by a holding ring and a ring spacer.
Since it is held firmly by the end plate and shift in the exhaust gas flow direction is prevented, it has become possible to prevent deformation of the cell shape and generation of cracks.

According to the second aspect of the invention, there is an advantage that the positioning of the exhaust gas outflow holes can be facilitated when the holding ring is assembled to the holding shaft. According to the third aspect of the invention, in manufacturing the metal carrier, the core, the holding ring, and the ring spacer can be easily positioned and held on the holding shaft by tightening the fastening nut.

[Brief description of the drawings]

FIG. 1 is a sectional view of a metal carrier according to an embodiment of the present invention.

FIG. 2 is an overall perspective view of a support shaft and a holding ring.

FIG. 3 is an exploded perspective view of the metal carrier shown in FIG.

FIG. 4 is a sectional view of a conventional metal carrier.

5 is a cross-sectional view of the end of the pipe of the metal carrier shown in FIG. 4 on the exhaust gas outflow side.

FIG. 6 is an enlarged perspective view of a portion A in FIG. 4;

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 21 Outer cylinder 23, 25, 27 Core 29 Holding shaft 31 Exhaust gas flow passage 33, 41, 47 Exhaust gas outflow hole 35 End plate 37, 39 Space 49 Ring spacer 51 Metal carrier

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat ゛ (Reference) B01J 35/04 301 B01J 35/04 321A 321 B01D 53/36 C F-term (Reference) 3G091 BA00 BA39 GA08 GB01X HA12 HA27 HA28 HA32 HA47 4D048 BA39X BB02 BB18 CC08 CC09 CC36 4G069 AA01 AA08 BA17 CA02 CA03 EA21 EA24 EA28 EB10 EE07 FA01 FB66

Claims (3)

[Claims] A metal outer cylinder (21), a thin metal corrugated sheet and a flat plate are wound in multiple layers, and the outer cylinder (2) is formed.
1) a plurality of cores (2
3, 25, 27) and an exhaust gas flow passage (31) penetrating through the center of each core (23, 25, 27), opening the exhaust gas inflow side and closing the other end side.
Is formed, and an end plate (35) is formed to abut on the downstream end surface (27a) of the last core (27), and a space (37, 37) between the cores (23, 25, 27) is formed.
A plurality of exhaust gas outflow holes (41, 33) communicating with the exhaust gas flow passage (31) are formed in a peripheral wall located at (39), and the holding shaft (29) corresponds to the exhaust gas outflow holes (41, 33). And holding shaft (2
9) a holding ring (45) having a plurality of exhaust gas outflow holes (47) formed in a peripheral wall thereof, which is sandwiched between the cores (23, 25, 27) and having the same inner diameter as the outer cylinder (21). The ring spacer (4) molded to the dimensions and held between the cores (23, 25, 27).
9) and a pressing member mounted on the exhaust gas inflow end of the holding shaft (29) and pressed against the upstream end surface (23a) of the foremost core (23). Metal carrier. 2. A holding shaft (29) or a holding ring (4).
5) Any one of the exhaust gas outflow holes (33, 41, 4)
7. A metal carrier for a catalytic converter according to claim 1, wherein the metal carrier is formed in an elongated shape in the circumferential direction. 3. The metal of a catalytic converter according to claim 1, wherein the pressing member is a tightening nut (43) screwed to the end of the holding shaft (29) on the exhaust gas inflow side. Carrier.