JP3217597B2 - Metal carrier for catalyst device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a metal carrier for a catalytic device which constitutes a honeycomb body used in an exhaust gas purifying apparatus for an internal combustion engine, and more particularly to a catalyst in which a roll-shaped honeycomb body is prevented from being broken or dropped due to thermal stress. The present invention relates to a metal carrier for a device.

[0002]

2. Description of the Related Art As shown in FIG. 4, a metal carrier for a catalyst device used in a conventional exhaust gas purifying apparatus is composed of a flat plate 31 and a corrugated plate 32 made of thin metal (0.05 to 0.10 mm).
A flat plate material 31 and a corrugated sheet material 32 are overlapped and wound in a roll form from the center to form a honeycomb body 34, and the brazing material is melted using a high vacuum furnace, and the brazing material is contacted. Bonding was performed at the part. A Ni-based brazing material was used for the brazing material, and a ferritic stainless steel material was used for the flat plate material and the corrugated sheet material. The thus-formed honeycomb body 34 accommodated in an outer cylinder 33 made of a thick metal plate (1-2 mm) is a metal carrier 40 for a catalyst device.
(For example, JP-A-56-4373).

[0003] A catalyst supporting layer made of alumina or the like is formed on the surface of the honeycomb passage of the honeycomb body, and a noble metal catalyst is supported on the catalyst supporting layer to serve as an exhaust gas purifying catalyst. And it is disposed in an exhaust passage of an internal combustion engine for purifying HC in exhaust gas, CO, etc. NO _x. In addition, since it is necessary to secure as many honeycomb passage areas as possible in a limited volume, the thickness of the flat plate member and the corrugated plate member is as thin as possible within a range where strength can be maintained.

[0004]

In the above-mentioned conventional metal carrier for a catalyst device which constitutes a honeycomb body, the flow rate of exhaust gas passing through the honeycomb body is larger as it goes from the outer layer to the inner layer of the honeycomb body. In the body, due to contact with high-temperature exhaust gas, heat generation due to catalytic reaction, and heat dissipation from the outer cylinder, a temperature distribution is generated in which the temperature is higher in the inner layer and lower in the outer layer. Due to this temperature distribution, the expansion and contraction amount of the inner layer portion of the high-temperature honeycomb body becomes larger than the expansion and contraction amount of the low-temperature outer layer portion, so that thermal stress is generated between the inner layer portion and the outer layer portion. . This thermal stress is repeated each time the honeycomb body expands and contracts, and is expanded and contracted by the outer cylinder.
The effect is remarkable in the outermost layer portion where the movement of the shrinkage is restricted. Therefore, as shown in FIG. 5, the outermost corrugated sheet material 32 of the honeycomb body 34 undergoes plastic deformation to cause metal fatigue, and finally breaks. There is a disadvantage that. In particular, when the outer cylinder 33 is made of a thick plate (1 to 2 mm), the temperature of the honeycomb body 34 increases because the outer cylinder 33 acts as a heat insulating material for the honeycomb body 34, and the outer cylinder 33 and the outer layer of the honeycomb body 34 are separated. The temperature difference is further increased, and the difference in thermal expansion between the two is increased. Therefore, stress concentrates on the brazed portion of the honeycomb body 34 close to the outer cylinder 33, and as shown in FIG. 5, there is a drawback that the corrugated sheet material 32 of the honeycomb body 34 is broken, and the weight increases. There are drawbacks.

As a countermeasure, if the thickness of the outer cylinder is reduced to reduce the rigidity of the outer cylinder, the outer cylinder is easily deformed, so that the thermal stress can be reduced. However, welding of the outer cylinder becomes difficult. Disadvantage.

[0006] Further, as shown in FIG.
By providing a plurality of openings 35 in the circumferential direction on the side surface of 3a, the cross-sectional area of the outer cylinder 33a on the circumference including the openings is reduced, and as shown in FIG. The deformation of the outer cylinder 33a corresponding to the elongation in the axial direction is facilitated, and the elongation of the honeycomb body 34 is reduced by cooling by the opening 35, so that the thermal stress of the brazed portion of the honeycomb body 34 is relaxed to suppress the crack. However, there is a drawback that the effect was not sufficiently obtained.

SUMMARY OF THE INVENTION An object of the present invention is to provide a novel metal carrier for a catalyst device which does not cause breakage due to thermal stress in a joint portion of an outer layer portion of a honeycomb body, is light in weight, easy to manufacture, and can reduce costs. Is to do.

[0008]

According to the present invention, there is provided a metal carrier for a catalyst device, comprising: a flat plate made of a thin metal plate having a flat band shape; and a thin metal plate having a corrugated unevenness continuously bent and formed into a band shape. A honeycomb body having a large number of mesh-shaped air passages formed by a corrugated sheet material abutting each other, overlapping with each other, being wound in a roll shape, and at least a part of the abutting portions being joined by a brazing material; A metal carrier for a catalyst device, which has at least a portion of the outer surface of the honeycomb body and an outer cylinder joined by a brazing material, wherein the metal carrier has at least one outer cylinder shorter than the axial length of the honeycomb body. ing.

The outer cylinder of the metal carrier for the catalyst device is provided at one end on the gas inlet side of the honeycomb body, or one at the gas inlet side end and one at the gas outlet side end of the honeycomb body. Alternatively, it is desirable that one be provided at the central portion in the axial direction of the honeycomb body.

[0010]

[Function] Since the length of the outer cylinder covering the roll-shaped honeycomb body is shorter than the length of the honeycomb body, the portion where expansion and contraction due to the heat of the honeycomb body is restricted by the outer cylinder is reduced, and the honeycomb body becomes Expansion and contraction can be easily performed in a portion without a cylinder, and the outer cylinder is less likely to act as a shielding material against heat radiation of the honeycomb body, so that the heat radiation of the honeycomb body is facilitated and the temperature rise can be suppressed. Further, even when a thick outer cylinder is used instead of a thin outer cylinder, the weight can be reduced and the manufacturing cost can be reduced.

[0011]

Next, embodiments of the present invention will be described with reference to the drawings. FIG. 1 is a perspective view of an embodiment of a metal carrier for a catalyst device of the present invention, and FIG. 1 (A) is a diagram in which one outer cylinder is provided at a gas inlet side end of a honeycomb body. (B)
FIG. 1 (C) is a diagram in which one outer cylinder is provided at both ends of a honeycomb body, and FIG. 1 (C) is a diagram in which one outer cylinder is provided at a central portion in the axial direction of the honeycomb body.

FIG. 2 is a schematic view of the honeycomb body shown in FIG. 1. FIG. 2 (A) is a perspective view, and FIG. 2 (B) is a schematic axial sectional view showing the configuration of a plate material. FIG. 3 is a schematic view of another embodiment of the honeycomb body of FIG. 1, in which FIG. 3 (A) is a perspective view and FIG. 3 (B) is a schematic axial sectional view showing a configuration of a plate material.

In FIG. 1A, a metal carrier 10 is formed by a honeycomb body 11 and an outer cylinder 12. As shown in FIGS. 2 (A) and 2 (B), the honeycomb body 11 has the flat plate member 1 and the corrugated plate member 2 overlap and contact with each other, and the brazing material 3
It is formed by winding into a roll with a steel sheet interposed therebetween. Outer cylinder 1
Reference numeral 2 denotes a cylinder which covers the outside of the honeycomb body 11, is disposed on the gas inlet side end face 11 a side of the honeycomb body 11, and a brazing material (not shown) is inserted between the honeycomb body 11 and the outside face. The axial length of the outer cylinder 12 is shorter than the length of the honeycomb body 11. In the assembly thus formed, the brazing material is melted by a normal processing step to join the plate material and join the honeycomb body and the outer cylinder, and the metal carrier 10 is obtained.

Whether the position of the end face 12a of the outer cylinder 12 is matched with the end face 11a of the honeycomb body, or whether the end face is arranged upstream or downstream of the gas flow from the end face 11a is determined by design requirements. In the embodiment shown in FIG. 1A, the end face 12a and the end face 11a coincide. FIG.
The embodiment shown in FIG. 1C is a special case of the embodiment shown in FIG. 1A, in which the outer cylinder 12 is disposed at the axial center of the honeycomb body 11 to form the metal carrier 30.

[0015] In FIG. 1 (B), the metallic substrate 20 is formed of a honeycomb body 11 and the two outer tube 12, 12 _1. The honeycomb body 11 is the same as that described with reference to FIG. The two outer cylinders 12 and 12 ₁ have the same shape as the outer cylinder 12 in FIG.
End faces 11a, 11b of the honeycomb body
And the end surfaces 12a and 12b of the outer cylinders are arranged so as to match each other. In this case, the two end faces 12 of the outer cylinder
a or 12b is an end face 11 of the honeycomb body 11, respectively.
It is needless to say that the gas flow can be displaced upstream or downstream with respect to the gas flow depending on design requirements with respect to a or 11b. The axial length of the outer tube 12 and the outer cylinder 12 ₁ may not be the same, it is determined by the design requirements.

Various methods can be used together to further reduce the rupture of the joined portion of the outer layer portion of the honeycomb body due to thermal stress, and the embodiment shown in FIGS. 3A and 3B is one example. is there. In other words, by superimposing two flat plate 1 without interposing a brazing material, between the wave plate 2 by interposing a brazing material 3 to form a honeycomb body 11 ₁ wound into a roll. In this case, the range in which the flat plate member 1 has the double structure is at least two layers from the outside of the honeycomb body. By providing the double structure of the flat plate material in the outer layer portion of the honeycomb body as described above, the difference in expansion and contraction based on the temperature difference between the two flat plate materials is absorbed between the two flat plate materials. Concentration of stress at the joint of the corrugated sheet material joined to the two flat sheet materials is avoided.

[0017]

As described above, according to the present invention, the axial length of the outer cylinder covering the roll-shaped honeycomb body is formed shorter than the entire length of the honeycomb body.
Shrinkage is less restricted by the outer cylinder, and also acts less as a shielding material against heat dissipation of the honeycomb body, which can suppress a rise in the temperature of the honeycomb body, thereby reducing breakage due to thermal stress of the honeycomb body. In addition, the weight is reduced, so that it can be used for an engine having a large vibration and can be easily manufactured, so that the cost can be reduced.

[Brief description of the drawings]

FIG. 1 is a perspective view of a metal carrier for a catalyst device of the present invention, in which FIG. 1 (A) is a diagram in which one outer cylinder is provided at a gas inlet side end of a honeycomb body, and FIG. 1 (B). FIG. 1C is a diagram in which outer cylinders are arranged at both ends of a honeycomb body, respectively, and FIG. 1C is a diagram in which one outer cylinder is arranged in a central portion in the axial direction of the honeycomb body.

FIG. 2 is a schematic view of the honeycomb body of FIG. 1, and FIG.
2 is a perspective view, and FIG. 2B is a schematic axial cross-sectional view showing a configuration of a plate material.

3 is a schematic view of another embodiment of the honeycomb body of the present invention, wherein FIG. 3 (A) is a perspective view, and FIG. 3 (B) is a schematic axial sectional view showing a configuration of a plate material.

FIG. 4 is a perspective view of a conventional metal carrier for a catalyst device.

FIG. 5 is a schematic axial sectional view of a metal carrier for a catalyst device according to a conventional technique, in which FIG. 5 (A) is a diagram showing a configuration of a plate material, and FIG. It is explanatory drawing which shows the state which performed.

FIG. 6 is a schematic axial cross-sectional view of another metal carrier for a catalyst device according to the prior art, in which FIG. 6 (A) shows a configuration of a plate material, and FIG. 6 (B) shows an outer cylinder due to thermal stress. It is explanatory drawing which shows the deformation state of.

[Explanation of symbols]

1, 31 Flat plate material 2, 32 Corrugated plate material 3 Brazing material 10, 20, 30, 40 Metal carrier 11, 11 ₁ , 34 Honeycomb body 11a, 11b, 12a, 12b End face 12, 12, ₁ , 33, 33a Outer cylinder 35 Opening

Continuation of the front page (58) Field surveyed (Int. Cl. ⁷ , DB name) B01J 21/00-37/36 B01D 53/86 F01N 3/28

Claims (4)

(57) [Claims] 1. A flat plate made of a thin metal plate having a flat band shape and a corrugated plate material made of a thin metal plate having a corrugated unevenness continuously bent and formed into a belt contact with each other and overlap each other. A honeycomb body having a large number of mesh-shaped air passages formed by being wound in a roll and having at least a part of the abutting portion joined by a brazing material; and at least one of an outer surface of the honeycomb body covering the honeycomb body. A metal carrier for a catalyst device having a portion and an outer cylinder joined by a brazing material, wherein the metal carrier has at least one outer cylinder shorter than an axial length of the honeycomb body. 2. The metal carrier for a catalyst device according to claim 1, wherein one of the outer cylinders is provided at a gas inlet side end of the honeycomb body. 3. The honeycomb structure according to claim 1, wherein one of the outer cylinders is provided at a gas inlet side end and a gas outlet side end of the honeycomb body.
5. The metal carrier for a catalyst device according to item 1. 4. The metal carrier for a catalyst device according to claim 1, wherein one outer cylinder is provided at a central portion in the axial direction of the honeycomb body.