JP3110914B2 - Honeycomb structure - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a honeycomb structure used as a metal carrier for a catalyst in an exhaust gas purifying apparatus for an internal combustion engine, and more particularly to a honeycomb structure formed in a roll shape.

[0002]

2. Description of the Related Art A catalytic metal carrier used in a conventional exhaust gas purifying apparatus is formed by stacking a strip-shaped flat plate and a corrugated plate and winding them into a roll to form a honeycomb structure. The honeycomb structure is made of metal. One stored in an outer cylinder is known (for example, JP-A-56-4373). In this metal carrier, the flat plate and the corrugated plate constituting the honeycomb structure, and the outer cylinder and the honeycomb structure are usually integrally joined by brazing. In this metal carrier, a catalyst supporting layer made of alumina or the like is formed on the surface of the honeycomb passage of the honeycomb structure, and the noble metal catalyst is supported on the catalyst supporting layer to serve as an exhaust gas purifying catalyst. And it is disposed in the exhaust passage of the internal combustion engine and purifies HC, CO, NOx and the like in the exhaust gas. Since it is necessary to secure as many honeycomb passage areas as possible in a limited volume, the thicknesses of the flat plate and the corrugated plate are made as thin as possible within a range where strength can be maintained.

In the above-described conventional catalyst metal carrier, the flow velocity of the exhaust gas passing through the honeycomb structure in the form of a roll increases from the outer peripheral portion to the central portion of the honeycomb structure. Due to the heat generated by the contact and catalytic reaction and the heat radiation from the outer cylinder to the outside air, a temperature distribution is generated in which the temperature is higher at the center and lower at the outer periphery,
This difference in the temperature distribution causes a difference in the amount of expansion and contraction between the honeycomb structure and the outer cylinder, but the radial and axial movement of the honeycomb structure is restricted by the outer cylinder, and the honeycomb structure is formed. Since the thickness of the flat plate and the corrugated plate is generally much smaller than the thickness of the outer cylinder, thermal stress acts on the honeycomb structure. By repeating the expansion and contraction, the outermost corrugated sheet of the honeycomb structure undergoes plastic deformation, causing metal fatigue, and finally the fracture of the corrugated sheet of the honeycomb structure and the joint between the honeycomb structure and the outer cylinder. There is a disadvantage that peeling occurs at the surface.

In order to eliminate this drawback, the shape of a conventional corrugated sheet or the joining of a corrugated sheet and a flat plate are as shown in FIG.
When a flat plate and a corrugated plate are joined by brazing to form a honeycomb structure, in order to obtain a flexible structure, a part of the tops and the bottoms of the corrugations of the corrugated plates 12 and 22 is substantially equidistant. And a structure having a structure in which the number of contact points between the flat plate and the corrugated plate is reduced (see Japanese Patent Application Laid-Open No. 62-83044). The top portion of the corrugated sheet that is in contact with the upper surface has a planar shape to form a first planar joint portion 31, and bend portions 33, 33 a, between the adjacent second planar joint portions 32.
33b and 33c (Japanese Utility Model Laid-Open No. 3-433).
No. 24).

[0005]

In the above-mentioned conventional honeycomb structure, the contact points between the flat plate and the top and bottom of the wave of the corrugated sheet, as shown in FIG. With the reduced structure, the joint area between the flat plate and the corrugated plate is small and sufficient brazing strength cannot be obtained. Therefore, when used as a catalyst metal carrier of an exhaust gas purification device, the honeycomb structure has There is a disadvantage that the central portion is displaced in the axial direction. In addition, as shown in FIG. 3, a corrugated plate having a planar shape at the top and having a bent portion between adjacent planar joints functions as a catalyst carrier by an area of the planar shape portion of the joint. In addition to the above, there are disadvantages that an extra corrugated sheet material is required to provide a bent portion on the corrugated sheet, and that there is a difficulty in making the bent portion.

SUMMARY OF THE INVENTION An object of the present invention is to provide sufficient strength in joining a flat plate and a corrugated sheet, preventing breakage of the corrugated sheet and exfoliation at the joint between the honeycomb structure and the outer cylinder, and a catalyst carrier. An object of the present invention is to provide a honeycomb structure that does not impair the function of the honeycomb structure and is easy to work.

[0007]

A honeycomb structure according to the present invention is composed of a large number of meshes formed by laminating a thin metal band-shaped flat plate and a band-shaped corrugated plate so as to abut each other and winding them into a roll shape. It has an air passage, and the top of the wave of the corrugated sheet abutting on either the outer surface or the inner surface of the flat plate is placed between the flat plate, every other ridge, every two ridges or every three ridges. There is a gap, and the contact portion of the corrugated plate is joined to the flat plate.

[0008]

A gap is provided between one side surface of the flat plate and the top of the wave of the corrugated plate abutting on the flat plate, at every other mountain, at every other mountain, or at every third mountain. , So that the expansion and contraction of the corrugated plate and the flat plate due to heat in the unbonded portion becomes easier than in the case where they are bonded, and the thermal stress received by the entire honeycomb structure becomes smaller, so that the temperature gradient In addition to the above, it is possible to prevent breakage of the corrugated sheet on the outer side of the honeycomb structure, and to increase the amount of catalyst since the top of the wave having a gap serves as a catalyst carrier.

[0009]

Next, embodiments of the present invention will be described with reference to the drawings. FIG. 1 is a view showing one embodiment of a honeycomb structure of the present invention, and FIG. 1 (A) is a schematic perspective view of a catalyst metal carrier of an exhaust gas purification device in which the honeycomb structure is housed in an outer cylinder;
FIGS. 1B, 1C, and 1D are schematic partial development cross-sectional views of the honeycomb structure of FIG. 1A, respectively. In FIG. One every other mountain, two every two mountains in FIG. 1 (C), and three every three mountains in FIG. 1 (D).
It is a figure which is joined to the mountain stand with the low wave tops interposed therebetween.

The metal carrier 1 is formed of a honeycomb structure 2 and a cylindrical outer tube 3 that houses the honeycomb structure 2. The honeycomb structure 2 is formed by laminating a thin metal band-shaped flat plate 4 and a band-shaped corrugated plate 5 so as to be in contact with each other and winding them in a roll shape. In FIG. 1B, the waves of the corrugated sheet 5 form a crest 6 ′ of a low wave every other crest, and a gap g is formed between the crest 6 ′ of the wave and the flat plate 4. Gap g
Is determined by the relationship between the thickness of the corrugated plate 5 and the flat plate 4 and the thickness of a brazing material (not shown) interposed between the corrugated plate and the flat plate. In a honeycomb structure of about 05 mm, 0.2 mm or more is required, and 0.25 mm or more is preferable. The brazing material is applied to the high wave top 6 and not to the low wave top 6 '.
Therefore, the catalyst can be effectively supported even at the low wave top 6 ′, and the catalyst supporting area can be increased. In addition, since the corrugated plate 5 is bonded to the flat plate 4 at all the bottom portions 7, there is no concern that the honeycomb structure is displaced in the axial direction.

In FIG. 1 (C), the wave of the corrugated plate 5 is provided with a peak 6 of a high wave at every other peak 6 'of a continuous low wave, and is joined to the flat plate 4 on the top side. Are all joined to the other flat plate 4. A gap g is formed between the low wave top 6 ′ and the flat plate 4. FIG. 1
In (D), a peak 6 of a high peak is provided at every third peak 6 ′ of a continuous low wave, and is joined to the flat plate 4 on the top side.

The corrugated sheet 5 used in the present honeycomb structure includes:
By a roll having a pitch circle capable of forming a corrugated sheet having an integral multiple of the pitch of a high wave by one rotation of a cylindrical roll that forms a corrugated sheet from a flat plate between intermeshing irregularities, it is completely different from a normal corrugated sheet manufacturing method. It can be easily manufactured as well.

[0013]

As described above, according to the present invention, the wave height of the corrugated sheet constituting the honeycomb structure is reduced at every other mountain, every two waves, or every three waves, so that By providing a gap between them, the thermal stress of the honeycomb body is relieved, so that the corrugated sheet can be prevented from breaking, and peeling does not occur at the joint between the honeycomb structure and the outer cylinder. In this case, sufficient strength can be maintained even in the case of bonding with the catalyst, the catalyst carrying area can be increased, and a honeycomb structure that can be easily manufactured can be obtained.

[Brief description of the drawings]

FIG. 1 is a view showing one embodiment of a honeycomb structure of the present invention, wherein FIG. 1 (A) is a schematic perspective view, and FIGS. 1 (B), (C),
(D) is a schematic partial development sectional schematic diagram of FIG. 1 (A), respectively.

FIG. 2 is a schematic partial cross-sectional schematic view of a honeycomb structure according to the related art.

FIG. 3 is a schematic partial cross-sectional schematic view of a honeycomb structure according to the related art.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Metal carrier 2 Honeycomb structure 3 Outer cylinder 4 Flat plate 5 Corrugated plate 6 High wave top 6 'Low wave top 7 Wave bottom 11,20,21 Flat plate 12,22 Corrugated plate 31 First planar joint 32 First 2 plane joints 33, 33a, 33b, 33c bent part g gap

──────────────────────────────────────────────────続 き Continued on front page (58) Field surveyed (Int. Cl. ⁷ , DB name) B32B 1/00-35/00

Claims (1)

(57) [Claims] 1. A honeycomb structure having a multiplicity of mesh-shaped air passages formed by laminating a thin metal band-shaped flat plate and a band-shaped corrugated plate so as to abut each other and winding the roll into a roll shape. A wave crest of the corrugated sheet abutting on one of an outer side surface and an inner side surface has a gap between every other peak, every two peaks, and every three peaks between the corrugated plate and the flat plate; Wherein the abutting portion is joined to the flat plate.