JP2004154699A - Metal carrier for catalyst - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To prevent the damage to a core occurring when the core is force-fitted to an outer cylinder, to maintain the joining strength between the core and the outer cylinder by a brazing foil metal, to prevent the clogging of cell passages caused by the brazing filler metal, also to increase purification efficiency by widening a range in which an exhaust gas flow becomes turbulent within the cell passages to the maximum while securing the fixed strength by spot welding of the brazing foil metal to the core. <P>SOLUTION: Alternatively stacked wavy sheets 11 and flat sheets 12 are wound so that the flat sheets 12 are located on the outside to form a core 1. A plurality of holes 11a are formed at optional intervals on the wavy sheets 11. A plurality of holes 12a are formed at optional intervals on the flat sheets 12 excepting the parts composing the outer circumferential faces. <P>COPYRIGHT: (C)2004,JPO

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a metal catalyst carrier mounted on an exhaust system such as an internal combustion engine.
[0002]
[Prior art]
Conventionally, a low foil material is wound around a part of the outer periphery of a core formed by alternately laminating a corrugated sheet and a flat plate made of a thin metal plate, and press-fitting them into a metal outer cylinder to perform heat treatment. By diffusion bonding the corrugated sheet and the flat plate thereby, and in a metal catalyst carrier in which the outer cylinder is bonded with a raw foil material, the corrugated sheet and the flat plate are wound so that the flat plate out of the alternately stacked corrugated plate and the flat plate is outside. There is a structure in which a plurality of holes are formed at arbitrary intervals only in the corrugated plate or in both the corrugated plate and the flat plate (for example, see Patent Document 1).
[0003]
[Patent Document 1]
JP-A-2002-143693 (Page 2, FIGS. 1 and 2)
[0004]
[Problems to be solved by the invention]
However, among the conventional metal thin plates having a structure in which a plurality of holes are formed at arbitrary intervals in both the corrugated plate and the flat plate, there are the following problems.
[0005]
In other words, there are a plurality of holes in the flat plate constituting the outer peripheral surface of the core, and the low foil material is wound around a part of the core outer peripheral surface instead of the entire outer peripheral surface. When press-fitting into the cylinder, the opening edge of each hole formed in the flat plate portion exposed on the outer surface of the core where the raw foil material is not wound is caught by the opening edge of the outer cylinder, making press-fitting difficult. Otherwise, there is a concern that cracks may be generated in the flat plate from the hole portion when the press-fitting is attempted.
[0006]
In addition, when the raw foil material is wound around the outer periphery of the core and heat-treated while being pressed into the outer cylinder, the liquefied brazing material flows into the hole formed in the flat plate, so that the core and the outer cylinder are separated from each other. There is a possibility that the joining strength may not be ensured, and there is a possibility that the brazing material flowing from the hole may block the cell passage.
[0007]
Further, when fixing the low foil material wound around the outer periphery of the core to the core by spot welding, there is a possibility that the spot welding position performed from the low foil material side coincides with the position of the hole of the flat plate hidden behind the back surface. As a result, since the fixing strength of the raw foil material to the core is reduced, there is a possibility that the pressed state of the raw foil material to the core may not be maintained when press-fitting into the outer cylinder. In addition, performing spot welding while confirming the position of the hole reduces the working efficiency.
You.
[0008]
Next, among the conventional metal thin plates having a structure in which a plurality of holes are formed at arbitrary intervals only on the corrugated sheet side, the range of turbulence in the cell passage is corrugated. Therefore, there is a problem in that the exhaust gas purification performance is inferior to that in which holes are formed in both the corrugated plate and the flat plate.
[0009]
In addition, as described above, the reason why the raw foil material is wound only on a part of the core, not on the entire outer peripheral surface of the core, is as follows.
In other words, the joint portion between the outer cylinder and the core is closely related to the durability of the carrier, and its contents will be explained from a general carrier breaking mechanism. Gas flows in. At that time, more gas flows to the center of the catalyst carrier, and the temperature becomes higher toward the center. Also, the temperature rises faster nearer the entrance. Eventually, the high-temperature region spreads toward the gas outlet, and the temperature of the entire catalyst becomes high. However, the temperature does not become uniform, and the temperature around the outer cylinder is lower than that inside due to cooling, heat radiation, and the like. Such a phenomenon causes a higher temperature gas to flow in not only at the time of engine start but also during acceleration during operation, resulting in a similar catalyst temperature profile.
[0010]
On the other hand, at the time of deceleration, low-temperature gas having an exhaust composition close to air flows in. The gas flow distribution flows more at the center than at the time of engine start and acceleration. That is, the central part and the inlet part are cooled quickly. The stress generated inside the catalyst carrier which has received such a temperature history is concentrated particularly at a portion joined to the outer cylinder. The reason is that the inner temperature is higher than the outer cylinder temperature, and the core that is expanding from the center of the catalyst carrier toward the outer cylinder is constrained by the outer cylinder, the outer peripheral part is compressed, and the core shrinks from the central part during cooling. Then, the outer peripheral portion that is joined to, that is, constrained with, the outer cylinder is elongated. As described above, since the joint between the outer cylinder and the core is subjected to repeated stresses of compression and tension, the joint is likely to be damaged by thermal fatigue.
[0011]
Such a catalyst carrier having a structure in which the outer cylinder and the core are joined receives thermal stress regardless of the position of the joining portion. In such a catalyst carrier, it is necessary to design such that the stress generation is small from the viewpoint of durability.In particular, both ends of the core, particularly, the inflow side of the exhaust gas having a large heat history is connected to the outer cylinder. If joined, there is a risk of breaking without being able to follow the heat shrinkage, so as described above, by winding the low foil material only on a part of the core outer peripheral surface instead of the entire outer peripheral surface, especially In addition, the core and the outer cylinder are prevented from being joined on the exhaust gas inflow side.
[0012]
The problem to be solved by the present invention is to prevent the core from being damaged when the core is pressed into the outer cylinder, to maintain the bonding strength between the core and the outer cylinder by the brazing foil material, and to block the cell passage by the brazing material. Provided is a metal catalyst carrier that can prevent and improve the purification efficiency by maximizing the range of turbulence in a cell passage while securing the fixing strength of a low foil material to a core by spot welding. It is in.
[0013]
[Means for Solving the Problems]
In order to solve the above-mentioned problem, the invention according to claim 1 is to provide a low foil material on a part of the outer periphery of a core formed by alternately laminating large corrugated plates and small corrugated plates or small corrugated plates or flat plates of a metal thin plate and winding them. Winding, diffusion-bonding the large corrugated plate and the small corrugated plate or flat plate by press-fitting them into a metal outer cylinder and performing heat treatment, and in a metal catalyst carrier in which the outer cylinder is joined with a low foil material, The core is formed by winding the large corrugated plate and the small corrugated plate or the flat plate out of the alternately laminated large corrugated plate or the flat plate so that the core is formed, and the large corrugated plate is formed with a plurality of holes at arbitrary intervals. A plurality of holes are formed in the small corrugated plate or flat plate at arbitrary intervals except for a portion constituting the outer peripheral surface of the core.
[0014]
The metal catalyst unit according to claim 2 is obtained by winding a low foil material around a part of the outer periphery of a core formed by alternately laminating large corrugated plates and small corrugated plates or flat plates made of thin metal plates and winding them. The large corrugated sheet and the small corrugated sheet or the small corrugated sheet or the flat plate are diffused and joined by press-fitting into a metal outer cylinder and heat-treated, and are alternately stacked on a metal catalyst carrier in which the outer cylinder is joined with a low foil material. The core is formed by winding the large corrugated plate and the small corrugated plate or the flat plate so that the large corrugated plate is on the outside,
A plurality of holes are formed at arbitrary intervals in the small corrugated plate or the flat plate, and a plurality of holes are formed at arbitrary intervals in the large corrugated plate except for a portion constituting an outer peripheral surface of the core. Means.
[0015]
[Action and effect]
According to the first aspect of the present invention, as described above, the corrugated plate or the corrugated plate or the flat plate portion that forms the outer peripheral surface of the core has no hole, so that the core with respect to the outer cylinder is not damaged without damaging the outer periphery of the core. Press-fitting can be performed smoothly.
[0016]
In addition, since the outer peripheral surface of the core joined to the outer cylinder by the braided foil material is formed of a small corrugated plate, a small corrugated plate or a flat plate without holes, the braid material liquefied during the heat treatment is a small corrugated plate or a small corrugated plate or It does not flow into the inside of the flat plate, whereby it is possible to maintain the bonding strength between the core and the outer cylinder by the brazing foil material, and to prevent the cell passage from being blocked by the flowing of the brazing material.
[0017]
In addition, since the outer peripheral surface of the core to which the low foil material is fixed by spot welding is composed of a small corrugated plate or a small corrugated plate or a flat plate without holes, the low foil material wound around the core is spot-welded. When fixing to the core, the work of fixing the low foil material can be performed without confirming the spot welding position, thereby fixing the low foil material to the core by spot welding without reducing the work efficiency. Strength can be ensured.
[0018]
In addition, since holes are formed not only in the large corrugated sheet but also in the small corrugated sheet or the flat plate except for the outer peripheral surface of the core, the range of turbulence in the cell passage is limited to both small corrugated sheets facing the large corrugated sheet. Alternatively, the purification efficiency can be increased by maximizing the range of turbulence in the cell passage without being limited to between the flat plates.
[0019]
According to the second aspect of the present invention, as described above, since the large corrugated plate portion forming the outer peripheral surface of the core is not formed with a hole, the press fit of the core into the outer cylinder can be smoothly performed without damaging the outer periphery of the core. Can do it.
[0020]
Also, since the outer peripheral surface of the core joined to the outer cylinder by the low foil material is formed of a large corrugated sheet without holes, the liquefied brazing material does not flow inside the large corrugated sheet during the heat treatment, Thereby, the joining strength between the core and the outer cylinder by the brazing foil material can be maintained, and the blockage of the cell passage due to the inflow of the brazing material can be prevented.
[0021]
Further, since the outer peripheral surface of the core to which the low foil material is fixed by spot welding is formed of a large corrugated plate without holes, the low foil material wound around the outer periphery of the core is fixed to the core by spot welding. At this time, the position of the ridge on the large corrugated sheet can be easily confirmed even from the outer surface side of the raw foil material, so that it is possible to secure the fixing strength by spot welding of the raw foil material to the core without lowering the work efficiency. it can.
[0022]
Further, since holes are formed not only in the small corrugated sheet or flat plate but also in a portion of the large corrugated sheet other than the outer peripheral surface of the core, the range of turbulent flow in the cell passage is limited to both faces facing the small corrugated sheet or flat plate. Without being limited to between the large corrugated sheets, the range of turbulence in the cell passage can be maximized to increase the purification efficiency.
[0023]
BEST MODE FOR CARRYING OUT THE INVENTION
Embodiments of the present invention will be described below with reference to the drawings.
(Embodiment 1)
The first embodiment of the present invention corresponds to the first aspect of the present invention.
First, a metal catalyst carrier according to a first embodiment of the present invention will be described with reference to the drawings. FIG. 1 is a partially cutaway perspective view showing a metal catalyst carrier according to Embodiment 1 of the present invention, and FIG. 2 is a perspective view showing a state in which a large corrugated sheet and a flat plate are being wound while being overlapped. 1 is a core, 2 is an outer cylinder, 3 is a raw foil material.
[0024]
The core 1 is formed in a honeycomb shape in which corrugated plates (large corrugated plates) 11 and flat plates (small corrugated plates or flat plates) 12 of metal thin plates having a thickness of several tens of microns are alternately stacked, and the flat plates 12 are arranged outside and wound in multiple layers. A catalyst carrier layer made of alumina or the like is formed on the surface of the honeycomb passage (cell passage), and a catalyst metal is carried on the catalyst carrier layer to form an exhaust gas purifying catalyst. By being disposed in the exhaust path, it functions to purify HC, CO, NOx, and the like in the exhaust gas.
[0025]
A plurality of holes 11a are previously formed in the corrugated plate 11 at predetermined intervals before being formed into a corrugated shape, while the flat plate 12 has a predetermined interval except for a portion constituting the outer peripheral surface of the core 1. Are formed with a plurality of holes 12a.
That is, in order to improve the exhaust gas purifying performance of the metal catalyst alone, turbulent flow is actively generated in the exhaust gas passing through the core 1, so that the chance of the exhaust gas contacting the catalyst is increased as much as possible. Therefore, a large number of holes 11a, 12a are formed in the corrugated sheet 1 and the flat plate 12 to allow the passage between the cell passages partitioned by the corrugated plate 1 and the flat plate 12, and exhaust in the core 1 is performed. By making the gas flow more turbulent in the width direction, the exhaust gas purification performance is improved.
[0026]
The outer cylinder 2 is formed of a SUS430 ferritic stainless steel plate having a thickness of 1 to 2 mm in a cylindrical shape, and has an inner diameter smaller than the outer diameter of the core 1 which is press-fitted into the outer cylinder. .
[0027]
The low foil material 3 is wound around the outer peripheral surface of the core 1 composed of the corrugated plate 11 before the core 1 is pressed into the outer cylinder. In the first embodiment of the present invention, Since the low foil material 3 is partially wound in the middle of the core 1 near the end on the exhaust gas outflow side (right side in the drawing), the low foil material 3 is not wound on both ends of the core 1. The non-rolled portions 1a and 1b are formed, and the non-rolled portions 1a and 1b are particularly formed so that the non-rolled portion 1a on the exhaust gas inflow side is sufficiently long.
[0028]
Next, the operation and effect of the first embodiment of the present invention will be described.
In the metal catalyst carrier according to the first embodiment of the present invention, since the hole 12a is not formed in the flat plate 12 constituting the outer peripheral surface of the core 1 as described above, the outer periphery of the core 1 is not damaged. The press-fitting of the core 1 into the outer cylinder 2 can be performed smoothly.
[0029]
Also, since the outer peripheral surface of the core 1 joined to the outer cylinder 2 by the braided foil material 3 is constituted by the flat plate 12 having no hole 12a, the liquefied brazing material flows into the flat plate 12 during the heat treatment. Accordingly, the bonding strength between the core 1 and the outer cylinder 2 by the raw foil material 3 can be maintained, and the blockage of the cell passage caused by the flow of the raw material to the inside of the flat plate 12 can be prevented. become able to.
[0030]
Further, since the outer peripheral surface of the core 1 to which the raw foil material 3 is fixed by spot welding is constituted by the flat plate 12 having no hole 12a, the raw foil material 3 wound around the outer periphery of the core 1 is spot-welded. At the time of fixing to the core 1, the fixing work of the raw foil material 3 can be performed without confirming the spot welding position, whereby the raw foil material 3 can be fixed to the core 1 without lowering the work efficiency. The fixing strength by spot welding can be secured.
[0031]
Further, since holes 12a are formed not only in the corrugated sheet 11 but also in a portion of the flat plate 12 excluding the outer peripheral surface of the core 1, the turbulent flow in the cell passage is limited to both faces facing the corrugated sheet 11 therebetween. It is not limited to between the flat plates 12, 12, thereby making it possible to maximize the range of turbulence in the cell passage and increase the purification efficiency.
[0032]
Next, another embodiment of the invention will be described. In the description of the other embodiments of the present invention, the same components as those of the first embodiment of the present invention are denoted by the same reference numerals, and the description thereof will be omitted. Only the differences will be described.
[0033]
(Embodiment 2)
A metal catalyst carrier according to a second embodiment of the present invention corresponds to the second aspect of the present invention.
FIG. 3 is a partially cutaway perspective view showing a metal catalyst carrier according to Embodiment 2 of the present invention, and FIG. 4 is a perspective view showing a state in which a corrugated plate and a flat plate are being wound while being overlapped.
[0034]
That is, as shown in both figures, the metal catalyst carrier of Embodiment 2 of the present invention is wound so that the corrugated plate 11 of the alternately laminated corrugated plate 11 and the flat plate 12 is on the outside, and the core 1 Are formed, and a plurality of holes 12a are formed in the flat plate 12 at arbitrary intervals, and the corrugated plate 11 is formed at arbitrary intervals except for a portion constituting the outer peripheral surface of the core 1. This embodiment differs from the first embodiment in that a plurality of holes 11a are formed, and the other points are the same as those in the first embodiment.
[0035]
Therefore, according to the metal catalyst carrier of Embodiment 2 of the present invention, as described above, since the hole 11a is not formed in the corrugated plate 11 constituting the outer peripheral surface of the core 1, the outer periphery of the core 1 is not formed. Can be smoothly pressed into the outer cylinder 2 without damaging the core.
[0036]
Further, since the outer peripheral surface of the core 1 joined to the outer cylinder 2 by the brazing foil material 3 is constituted by the corrugated sheet 11 having no hole 11a, the brazing material liquefied during the heat treatment is at least inside the corrugated sheet 11. Accordingly, the bonding strength between the core 1 and the outer cylinder 2 by the raw foil material 3 can be maintained, and the blockage of the cell passage caused by the flow of the raw material to the inside of the corrugated sheet 11 can be prevented. Can be prevented.
[0037]
Further, since the outer peripheral surface of the core 1 to which the raw foil material 3 is fixed by spot welding is constituted by the corrugated plate 11 having no hole 11a, the raw foil material 3 wound around the outer periphery of the core 1 is spot-welded. When fixing to the core 1, the position of the ridge on the corrugated sheet 11 can be easily confirmed even from the outer surface side of the raw foil material 3, so that it is possible to securely join without lowering the working efficiency, The fixing strength by spot welding of the low foil material 3 to the core 1 can be secured.
[0038]
Further, since the holes 11a are formed not only in the flat plate 12 but also in a portion of the corrugated plate 11 other than the outer peripheral surface of the core 1, the range of turbulence in the cell passage is limited to the two waves facing each other across the flat plate 12. It is not limited to between the plates 12, 12, which makes it possible to maximize the range of turbulence in the cell passage and increase the purification efficiency.
[0039]
In addition, since the corrugated sheet 11 and the flat sheet 12 that are alternately stacked are wound so that the corrugated sheet 11 is located outside, the brazing material liquefied during the heat treatment permeates a wide range to a position outside a predetermined range due to a capillary phenomenon. Outflow can be suppressed.
[0040]
Further, since the corrugated plate 11 has a higher degree of freedom of expansion and contraction than the flat plate 12, by arranging the corrugated plate 11 on the outer peripheral side of the core 1, a honeycomb structure having a honeycomb structure is formed by a compression action when the corrugated plate 11 is pressed into the outer cylinder 2. The buckling of the core 1 can be suppressed by the expansion and contraction of the corrugated sheet 11 on the outer periphery.
[0041]
Although the embodiment of the present invention has been described above, the present invention is not limited to the above-described embodiment of the present invention, and even if there is a design change or the like without departing from the gist of the present invention, the present invention is not limited to the embodiment. included.
For example, in the embodiment of the invention, the raw foil material 3 is wound at a position near the end on the exhaust gas outflow side of the core 1, but may be formed in an intermediate portion.
[0042]
Further, in the embodiment of the present invention, the holes 11a and 12a are formed as long holes in the flow direction of the exhaust gas, but the shape and arrangement are arbitrary.
Further, in the embodiment of the present invention, an example in which the flat plate 12 is used has been described. However, a similar effect can be obtained by using a small corrugated plate.
[Brief description of the drawings]
FIG. 1 is a partially cutaway perspective view showing a metal catalyst carrier according to Embodiment 1 of the present invention.
FIG. 2 is a perspective view showing a state in which a corrugated plate and a flat plate are being wound on the metal catalyst carrier according to Embodiment 1 of the present invention.
FIG. 3 is a partially cutaway perspective view showing a metal catalyst carrier according to Embodiment 2 of the present invention.
FIG. 4 is a perspective view showing a state in which a corrugated plate and a flat plate are being wound on a metal catalyst carrier according to Embodiment 2 of the present invention.
[Explanation of symbols]
Reference Signs List 1 core 1a unwound portion 1b unwound portion 11 corrugated sheet (large corrugated sheet)
11a hole 12 flat plate (small corrugated plate or flat plate)
12a hole 2 outer cylinder 3 raw foil material

Claims (2)

A low foil material is wound around a part of a core formed by alternately laminating large corrugated and small corrugated plates or flat plates made of a thin metal plate, and press-fitting these into a metal outer cylinder for heat treatment. By diffusion bonding the large corrugated sheet and the small corrugated sheet or flat plate by doing, in the metal catalyst carrier that the outer cylinder is joined with a low foil material,
The core is formed by winding such that the large corrugated sheet and the small corrugated sheet or the flat plate are alternately stacked so that the small corrugated sheet or the flat plate is on the outside,
A plurality of holes are formed at arbitrary intervals in the large corrugated sheet,
A metal catalyst carrier, wherein a plurality of holes are formed in the small corrugated plate or the flat plate at arbitrary intervals except for a portion constituting an outer peripheral surface of the core. A low foil material is wound around a part of a core formed by alternately laminating large corrugated and small corrugated plates or flat plates made of a thin metal plate, and press-fitting these into a metal outer cylinder for heat treatment. By diffusion bonding the large corrugated sheet and the small corrugated sheet or flat plate by doing, in the metal catalyst carrier that the outer cylinder is joined with a low foil material,
The core is formed by winding such that the large corrugated plate and the small corrugated plate or the flat plate are alternately stacked such that the large corrugated plate is on the outside,
A plurality of holes are formed at arbitrary intervals in the wave plate or flat plate,
A metal catalyst carrier, wherein a plurality of holes are formed in the large corrugated plate at arbitrary intervals except for a portion constituting an outer peripheral surface of the core.

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