JP3037365B2 - Exhaust gas purification device - Google Patents

Description

[Detailed Description of the Invention] (Object of the Invention) (Industrial application field) The present invention generally carries an exhaust gas purifying catalyst which is interposed in the middle of an exhaust pipe as a means for purifying exhaust gas of an automobile. Exhaust gas purification device comprising a metallic honeycomb body for the purpose.

More specifically, the present invention relates to a heat-resistant flat plate member and a corrugated band member, which are constituent members of a metal honeycomb body, provided with at least fine irregularities on the surface of the corrugated plate member. Exhaust gas purifying device that can improve not only the retention of waveform and the productivity of corrugated strips in the process of manufacturing a honeycomb body by using them, but also the joining strength of the abutting portions of both strips. It is about.

(Prior Art) Conventionally, this type of exhaust gas purifying apparatus generally includes a flat strip made of a heat-resistant thin steel sheet and a corrugated strip formed by corrugating the thin steel sheet, and abutting portions thereof. A honeycomb-shaped laminate having a large number of mesh-shaped vent holes for an exhaust gas passage in the axial direction manufactured by stacking them in a spiral pattern or by stacking them in a layered manner Body (hereinafter,
It is called a honeycomb body. ) And a cylindrical metal case with both ends opened for loading and fixing the honeycomb body.

In recent years, in view of price competition with the conventional cordierite-based ceramic carrier, there is no special use of a metal case for loading and firmly fixing the honeycomb body, that is, exhaust gas using only the metal honeycomb body. There is a movement to configure a catalytic converter for purification. In this case, since the metal case is not used, the manufacturing cost of the metal case, the loading and fixing cost of the metal case and the metal honeycomb body, so-called canning cost, and the like are reduced, and it goes without saying that significant cost merit is generated. There is no such thing.

In the metal exhaust gas purifying apparatus of this type, the honeycomb body and the metal case, and the flat band material and the corrugated band material constituting the honeycomb body are formed by a high temperature of the exhaust gas itself and the exhaust gas and the honeycomb. Welding to withstand thermal expansion and thermal stress due to exothermic reaction with a purification catalyst (Pt, Pd, Rh, etc.) carried on the body wall, and to withstand vibration during driving of automobiles It is fixed by contact or mechanical engagement means.

As described above, a honeycomb body, which is a main component of this type of exhaust gas purifying apparatus, is a thin heat-resistant steel sheet, more specifically, for example, Fe3-Cr20% -Al5% having a thickness of 0.03 to 0.1 mm.
Heat-resistant stainless steel (or a rare-earth element or compound added to improve oxidation resistance)
For example, a hoop material having a desired width, that is, a flat strip and a corrugated strip obtained by corrugating the flat strip are adjusted, and these members are stacked so as to abut each other. It is manufactured.

In the manufacturing process of the honeycomb body, for example, when a flat-shaped strip and a corrugated strip are stacked so as to be in contact with each other, and these are wound and laminated in a spiral pattern to manufacture a wound-type honeycomb body. One particular problem is that the corrugated strip material loses its waveform holding force (rigidity) to the winding stress, and a large number of exhaust gases formed in the axial direction of the honeycomb body after the winding is completed. This means that the ventilation holes (also called cells) become non-uniform. That is, non-uniform cell shapes and non-uniform cell formation densities occur, making it impossible to efficiently manufacture a uniform honeycomb body. For this reason, the winding speed and the like must be set to a low value, and the honeycomb body must be manufactured under the condition that the waveform is not deformed. The point mentioned above is
The same applies to a hierarchical type honeycomb body manufactured by stacking a flat strip and a corrugated strip in a layered manner so as to abut each other. There is a disadvantage that the waveform shape is deformed due to external stress applied when mounting.

As described above, in the manufacturing process of the honeycomb body, the low waveform holding force (rigidity) of the corrugated strip material brings a great disadvantage to the performance of the exhaust gas purification device. That is, due to non-uniform cell shapes and non-uniform cell formation densities, the pressure loss of exhaust gas is increased and the engine efficiency is reduced, and uniform exhaust gas purification performance is not maintained.
Brings serious flaws.

(Problems to be Solved by the Invention) The present invention has been made to solve the above-mentioned drawbacks of the honeycomb body which is a main component of the conventional exhaust gas purifying apparatus.

The present inventor has studied to improve the waveform holding force (rigidity) of the corrugated strip constituting the honeycomb body in order to solve the above-mentioned drawbacks. At that time, the present inventors have studied to simultaneously improve the joining strength between the flat band material and the corrugated band material required for this kind of honeycomb body.

As a result, when the present inventors roughened the flat sheet material and the corrugated sheet material constituting the honeycomb body so that at least the surface of the corrugated sheet material has irregularities of a specific height. In addition, the corrugated band material exerts sufficient waveform holding force (rigidity) against external stress applied in the manufacturing process of the honeycomb body, and after the honeycomb body is formed, the flat band material and the corrugated band material are formed. It has been found that the brazing at the contact portion with the material is joined with sufficient strength, and the present invention has been completed.

[Configuration of the invention]

(Means for Solving the Problems) To summarize the present invention, the present invention relates to an axial direction manufactured by stacking a flat band member and a corrugated band member of a thin metal plate so as to abut each other. In an exhaust gas purifying apparatus comprising a honeycomb core body for supporting an exhaust gas purifying catalyst having a large number of mesh-shaped vent holes, the corrugated sheet material has a height of at least 5 The present invention relates to an exhaust gas purifying apparatus characterized by having a roughened region having fine irregularities of 50 μm.

 Hereinafter, the technical configuration of the present invention will be described in detail.

The present invention has a major feature in a honeycomb body which is a main component of an exhaust gas purifying apparatus, in particular, eliminating a drawback introduced from a manufacturing process thereof and providing a honeycomb body which exhibits excellent characteristics. is there.

The greatest drawback introduced from the manufacturing process of the honeycomb body is that, as described above, among the flat band material and the corrugated band material, which are heat-resistant thin steel plates, which are members constituting the honeycomb core body, particularly the corrugated plate material This is due to the low waveform holding force (rigidity) of the strip.

The present invention provides a honeycomb body using a corrugated strip obtained by roughening a part or all of the surface of the corrugated strip in order to improve the waveform holding force (rigidity) of the corrugated strip. Is adopted. It goes without saying that the front surface of the corrugated strip means one surface and / or the back surface.

Further, according to the present invention, when the abutting portion of the corrugated sheet material and the flat sheet material is brazed to form a honeycomb body, the wettability of the brazing material is promoted by the capillary phenomenon of irregularities in the roughened region. Based on the finding that the roughened region formed on the surface of the corrugated strip is set to a portion particularly in contact with the flat strip, specifically, to the top of the corrugation of the corrugated strip. Adopt technical means. In the present invention, the roughened region set at the top of the waveform may be, for example, any one of the peaks and valleys of the waveform and at least a portion in contact with the flat band material.

In addition, the improvement of the joining strength of the abutting portion between the flat band material and the corrugated band material is, for a metal exhaust gas purifying device,
Needless to say, it has a significant meaning. That is, the honeycomb body, which is a main component of the metal exhaust gas purifying apparatus, is heated in the axial direction (exhaust direction) of the honeycomb body under the high temperature of the high temperature of the exhaust gas itself or heat generated by the contact reaction between the exhaust gas and the catalyst layer. (Inflow / outflow direction of gas, passing direction). In particular, since the flow rate of the exhaust gas is higher in the axial portion of the honeycomb body than in the outer peripheral portion, the contact reaction with the catalyst layer progresses and the temperature becomes high, and the central portion protrudes outward (also referred to as scoping or film out). )

As described above, in the honeycomb body, the flat band material and the corrugated band material constituting the honeycomb body are displaced from each other to cause delamination. Vibration is also added, and the tendency to peel is promoted. In addition, with the occurrence of peeling, not only the strength of the honeycomb body is reduced, but also the cracks, cracks, and breakage of the flat or corrugated strips constituting the honeycomb body occur, and the performance as an exhaust gas purification device is fully demonstrated for a long time You can't do that.

The present invention solves the above-mentioned problem of delamination between the flat band material and the corrugated band material by solving the problem of fineness provided on the corrugated band material surface in order to improve the waveform holding force (rigidity) of the corrugated band material. It can be eliminated with a rough surface with unevenness.

In the present invention, the above-mentioned improvement in the waveform holding force (rigidity) of the corrugated strip is directly or indirectly performed by finely embossing at least a part of the surface of the corrugated strip. It must be noted that this is achieved.

That is, when the surface of the corrugated strip is subjected to fine unevenness processing by, for example, mechanical processing by plastic deformation, the hardness of the strip is directly increased by work hardening, and the above-described waveform holding force (rigidity) is improved. You.

Further, even when the surface of the corrugated sheet is subjected to fine unevenness by, for example, chemical etching or photoetching, the coefficient of friction of the corrugated sheet increases and the lamination with the flat sheet is performed. Is suppressed, that is, the waveform holding force is indirectly improved.

According to the present invention, the fine irregularities formed on the surface of the corrugated sheet material are processed to the extent that the deformation of the waveform is prevented with respect to the external stress applied in the process of manufacturing the honeycomb body. The surface may be roughened. From the viewpoint of the above-described waveform holding force (rigidity) and the permeability of the brazing material at the time of brazing, the surface is roughened, that is, the height of the unevenness is 5 to 50 μm, and the density of the unevenness is 1 to 10 ³ pieces / mm ² is sufficient.

In the present invention, there is no particular limitation on the method of roughening by fine unevenness processing applied to the surface of the corrugated strip material. For example, a corrugated forming gear having a fine uneven surface (hereinafter, referred to as a roughened forming gear).
Alternatively, the surface may be roughened by a processing roll (hereinafter, referred to as a roughening roll), or by chemical etching, photoetching, or the like.

Japanese Patent Application Laid-Open No. 1-280613 discloses that, at a contact portion between a corrugated plate and a flat plate constituting a honeycomb body, a brazing material used for brazing and a reaction between a post-coated and supported catalyst component are carried out. As a technique for preventing a decrease in catalytic activity, a concave portion, more specifically, one or more concave grooves extending in the width direction of the corrugated sheet is formed at the top of the corrugated sheet, and a brazing material is applied to the concave groove. In addition, a device that holds a brazing material is disclosed. This is different from the method of roughening the surface of the corrugated band material to have fine irregularities for the purpose of improving the corrugated sheet holding force (rigidity) of the present invention. Further, the brazing according to the present invention, the penetration of the brazing material by the capillary phenomenon of the fine irregularities,
This is due to diffusion and differs from this point as well.

In the present invention, in order to eliminate the drawbacks particularly caused by the lack of the waveform holding force (rigidity) during the manufacture of the honeycomb body of the corrugated strip, the corrugated strip has fine irregularities on the side thereof. Although the roughened region is formed, it goes without saying that the roughened region may be formed also on the flat strip side. In this case, it is preferable to form a roughened region in a portion where the flat strip material comes into contact with the corrugated strip material, from the viewpoint of increasing the friction coefficient at the contact portion between the two strip materials. Accordingly, for example, when a stack of a flat strip and a corrugated strip is rolled and laminated, the waveform holding force of the corrugated strip is reliably improved. This also meets the demand for increasing the bonding strength of the contact portion between the flat strip and the corrugated strip. That is, when the contact portion is brazed, the wettability of the brazing material is doubled by the capillary phenomenon in the roughened region provided in each band material, and the uniform penetration of the brazing material into the inside of the contact surface is further promoted. Is done. As a result, the brazing material at the abutting portion of the two strips completely penetrates into the abutting portion, thereby preventing the formation of a large fillet (a brazing material pool) near the abutting portion, and the catalyst carried on the surface. It is possible to prevent a decrease in catalytic activity based on the reaction with the brazing material.

(Example) Hereinafter, an example of the present invention will be described in more detail with reference to the drawings. It goes without saying that the present invention is not limited to those described in the embodiments and those shown in the drawings. In particular, in the present invention, since the corrugated strip which is a constituent member of the honeycomb body has characteristics, the corrugated strip will be mainly described.

(I) FIG. 1 shows the exhaust gas purifying apparatus (A) of the first embodiment of the present invention, in which a flat strip (11) and a corrugated strip (12) constituting a honeycomb body (1) are formed. It is a principal part expanded sectional view of the contact part of FIG.

In the present invention, as shown in FIG. 6, the exhaust gas purifying device (A) comprises a flat strip (11) and a corrugated strip (12).
Has a spirally wound honeycomb body (1), or a flat strip material (11) and a corrugated strip material (12) as shown in FIG. It may have a honeycomb body (1) of a hierarchical type stacked in a hierarchical manner. By alternately stacking the two strips (11, 12), the exhaust gas passage (cell) (13) is automatically formed. 6 and 7 show a honeycomb body (1) loaded and fixed in a cylindrical metal case (2), but the metal case (2) is omitted. You may.
In the present invention, the cross-sectional shape of the metal case may be a desired shape such as an elliptical shape or a triangular shape.

As shown in FIG. 1, a portion of the corrugated strip (12), which is a substantially trapezoidal wave, in contact with the flat strip (11) has a roughened region (12W) with fine irregularities. This roughened area (12
W) can be formed in the manner shown in FIG. 3 or FIG. In the present invention, the corrugated sheet material (1
It goes without saying that the waveform of 2) may have a desired shape.

Fig. 3 shows that when a flat band material (11) is passed between a pair of forming gears (FG) and corrugated, one of the gears is roughened FG so that It shows an aspect in which a roughened region (12W) is formed.

FIG. 4 shows a corrugated strip (1) between a pair of rolls (R).
In this case, when the surface is roughened by passing through 2), one of the rolls is used as a roughening roll R to form a roughened region (12W).

In order to form a roughened area (12W) on the top of the corrugation of the corrugated sheet material, that is, on both the peaks and valleys and on the side in contact with the flat sheet material (11), The surface roughening method shown in FIGS. 3 and 4 may be used in combination.

(Ii) FIG. 2 shows the exhaust gas purifying apparatus (A) according to the second embodiment of the present invention, in which a flat strip (11) and a corrugated strip (12) constituting a honeycomb body (1) are formed. 3 is an enlarged cross-sectional view of a main part of a contact portion of FIG.

2 has a roughened area (11W) also on the side of the flat strip material (11). The flat strip material (11) having such a roughened area (11W) may be adjusted in the manner shown in FIG. That is, of a set of roles,
By making one of the rolls a roughened roll R, the flat band material (11) is passed between the rolls to form a roughened area (11).
W) may be formed.

(Iii) The exhaust gas purification device (A) was manufactured in the following manner.

(A) Flat strip A metal strip having a thickness of 0.05 mm and a width of 70 mm made of heat-resistant steel of 20% Cr and 5% Al was used.

(B) Corrugated strip material From a heat-resistant steel of the same type as the flat strip material, a pair of forming gears (as shown in FIG. 3, one of which has a rough surface having fine irregularities with a height of irregularities of about 30 μm). Using a flattened FG), a corrugated metal strip with a pitch width of 3.5 mm, a peak height of 1.8 mm, and a rough surface with fine irregularities at the top of the peak is manufactured. did. The flat band material and the corrugated band material were stacked on each other, and wound and laminated in a spiral to obtain a honeycomb body having an outer diameter of 70 mm.

During the winding and lamination, the honeycomb body having a uniform cell shape was obtained without the waveform of the corrugated strip being deformed. It should be noted that the shape retention was sufficient even if the winding speed (productivity) was increased by about 20%, as compared with the conventional one having no roughened region.

Next, the honeycomb body was packed in a cylindrical metal casing having an inner diameter of 70 mm, and both ends 10 mm were immersed in a slurry bath of a Ni-based high-temperature brazing material, dried, and then brazed in a vacuum heating furnace to form an exhaust gas. The purification device (A) was manufactured.

The exhaust gas purification device (A) manufactured in this way is
When a 50-cycle rapid heat quenching test between normal temperature and 900 ° C (burner spalling test) and a vibration resistance test were performed,
There is no separation or separation of the contact part between the flat strip and the corrugated strip,
It was found that the brazing was firmly performed.

〔The invention's effect〕

The present invention relates to an exhaust gas purifying apparatus comprising a metallic honeycomb body composed of a thin heat-resistant flat band material and a corrugated band material, wherein at least the corrugated sheet material of the band material constituting the honeycomb body is provided. The band is characterized in that it is formed of a material having a roughened region with fine irregularities on its surface. As a result, the following excellent effects can be obtained. (1) When manufacturing a honeycomb body, the corrugated strip particularly tends to be deformed by the load of external stress. Corrugated sheet retention (rigidity) is sufficiently enhanced and improved. Therefore, the shape (cell shape) of the mesh-shaped vent hole channel (cell) 1 of the exhaust gas formed by winding or layering the flat strip material and the corrugated strip material is constant, and the cell formation density Can be manufactured with high characteristics. Needless to say, the fact that the cell shape and the formation density are constant is preferable in terms of engine efficiency, exhaust gas purification ability, and the like.

(2) In an exhaust gas device of this kind, particularly in a honeycomb body which is a main component, a flat plate member and a corrugated plate member contact each other in order to withstand long-term use under severe use conditions. The part is required to be firmly fixed. In the present invention, the roughened region of the fine irregularities formed on the surface of the corrugated strip material allows the molten brazing material to efficiently penetrate into the abutting portions of the two strip materials by capillary action. Therefore, both the band members are firmly brazed, and the reaction between the brazing material applied to the abutting portion and the exhaust gas purifying catalyst which is subsequently coated and supported (that is, high). Achieving catalytic performance).

[Brief description of the drawings]

FIG. 1 is an enlarged sectional view of a main part of a contact portion between a flat strip and a corrugated strip according to the first embodiment of the present invention. FIG. 2 is an enlarged cross-sectional view of a main part of a contact portion between a flat strip and a corrugated strip according to a second embodiment of the present invention. FIG. 3 is a view for explaining a first embodiment for producing a corrugated strip having a roughened region, and FIG. 4 is a view for explaining a second embodiment. FIG. 5 is a view for explaining a mode of manufacturing a flat strip having a roughened region. FIG. 6 is a front view of the exhaust gas purifying apparatus of the first embodiment of the present invention, and FIG. 7 is a front view of the exhaust gas purifying apparatus of the second embodiment. A: Exhaust gas purifying device 1: Honeycomb body 11: Flat strip material 12: Corrugated strip material 13: Rope-shaped vent hole 2 ... Casing 11W, 12W ... Roughened area

Claims (4)

(57) [Claims] An exhaust gas purifying catalyst having a large number of mesh-shaped vent holes in the axial direction manufactured by laminating a flat band member and a corrugated band member of a thin metal plate so as to abut each other. In the exhaust gas purifying apparatus comprising a honeycomb core body for supporting the corrugated sheet, the corrugated strip has at least a part of its surface having a roughened region with fine unevenness having a height of 5 to 50 μm. An exhaust gas purifier characterized by the above-mentioned. 2. A corrugated strip having a height of 5 to 50 μm on a surface of at least one of the corrugated peaks (peaks and valleys) on the side in contact with the flat strip. 2. The exhaust gas purifying apparatus according to claim 1, wherein the exhaust gas purifying apparatus has an uneven surface roughened region. 3. The exhaust system according to claim 1, wherein said flat strip has a roughened surface with fine unevenness having a height of 5 to 50 μm at a portion in contact with the corrugated strip. Gas purification device. Wherein said roughened area, the fine irregularities of height 5 to 50 [mu] m, either as in claim items 1 to 3, wherein those provided 1-10 ^three percentage per mm The exhaust gas purifying apparatus according to claim 1.