JP2521839Y2 - Metal carrier - 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 supporting a catalyst for purifying automobile exhaust gas.

[0002]

2. Description of the Related Art As a carrier for carrying a catalyst for purifying exhaust gas from automobiles, a honeycomb-shaped metal made of heat-resistant stainless steel flat foil (referred to as flat foil) and corrugated foil (referred to as corrugated foil). Carriers are receiving attention. It is important that these metal carriers not only have heat resistance and oxidation resistance to withstand high-temperature exhaust gas, but also can withstand thermal stress and thermal fatigue due to the heat cycle of heating and cooling and the difference in temperature distribution of the honeycomb body. .

As measures against thermal stress and thermal fatigue due to thermal cycling, Japanese Patent Application Laid-Open No. 62-273050 and Japanese Patent Application Laid-Open
Japanese Patent Application Laid-Open No. Sho 62-83044 discloses a method in which only the end of the foil as disclosed in each publication of No. 3051 is joined to the outer cylinder in the axial direction, and the flat foil and the corrugated foil of the honeycomb body are not joined. As disclosed, flat foil is also deformed with a large cycle,
There is a method in which a wave having a small wavelength is applied to the corrugated foil to give an extra deformation allowance to the cells of the honeycomb body formed at the joining points, thereby relaxing thermal stress.

In the former method, since the end of the foil is bonded only to the outer cylinder, the flat foil and the corrugated foil inside the honeycomb body may be displaced by high-temperature and high-speed exhaust gas. In the latter method, it is difficult to wind the foil, and at the same time, it is difficult to wind the foil, and it is also difficult to stably join the contacts. Therefore, it is easy to cause a bonding failure of each cell, and the honeycomb body lacks structural stability.

There is also a method of mechanically fixing a honeycomb body as disclosed in JP-A-62-160728.
Since the honeycomb body is separated from the outer cylinder, the honeycomb body vibrates inside the outer cylinder, and the carried catalyst falls off, so that the purification ability is reduced.

On the other hand, attempts have been made to reduce the thermal stress by improving the joining method of the flat-corrugated foil of the honeycomb body with the brazing material. That is, a portal structure in which the vicinity of the upper end portion of the honeycomb body and several layers of the outer peripheral portion are brazed, and a target structure in which the vicinity of the upper and lower ends of the honeycomb body are brazed are proposed. Brazing materials are generally expensive, so it is preferable to have as few joints as possible, for which the above structure is consistent. However, in a thin honeycomb body having a short length as recently proposed, in the portal structure, the honeycomb body is deformed into a depressed shape due to insufficient synthesis in the axial direction. It is difficult to determine the dozens of structures and dimensions between the honeycomb body and the outer cylinder, and even if the dimensions are forcibly determined, the free length is short and the structure is close to a rigid structure, and the durability is lost.

[0007]

[Problems to be Solved by the Invention] In the present invention, the internal structure of the honeycomb body is made rigid and the structure of the honeycomb body and the outer cylinder is made flexible, so that the heat stress and heat generated by the heating / cooling cycle are reduced. The purpose of the present invention is to provide a metal carrier having excellent durability while preventing breakage and damage of a metal honeycomb body caused by fatigue, destruction occurring between an outer cylinder and a honeycomb body, and the like, and also having a thin honeycomb body. Is what you do.

[0008]

SUMMARY OF THE INVENTION In order to achieve the above object, the gist of the present invention is to provide a honeycomb body formed by winding a metal flat foil and a corrugated foil one on top of another and spirally forming a laminate. In a metal carrier that is housed in an outer cylinder and joined to the flat foil-corrugated foil contact portion of the honeycomb body, one layer between the innermost one and four layers from the outermost periphery of the honeycomb body, near the upper end thereof, or A metal carrier characterized in that a portion excluding the vicinity of a lower end portion is non-joined, and an outer periphery of a honeycomb body and an inner periphery of an outer cylinder are joined within a range of the non-joined portion. In the present invention, it is preferable that the honeycomb body is formed by diffusion bonding at the flat foil-corrugated foil contact portion, or by brazing or diffusion bonding the outer circumference of the honeycomb body and the inner circumference of the outer cylinder.

As described above, according to the present invention, since the inside of the honeycomb body non-bonding layer has a rigid structure and the outer cylinder has a flexible structure, the honeycomb body expands sufficiently in the axial direction as well as in the radial direction, so that the thermal expansion is achieved. Stress can be reduced. In addition, since the non-bonding layer is a single layer, thermal stress acts on the same layer in a shearing manner and does not act as bending, so that the honeycomb body is less deformed.

Hereinafter, the present invention will be described in detail based on an embodiment shown in the drawings. FIG. 1 is a longitudinal sectional view schematically showing an example of the present invention, in which 1 is a honeycomb body, 2 is an outer cylinder containing the honeycomb body 1, and 3 is a non-woven body provided on the honeycomb body 1. Reference numeral 4 denotes a joining portion that joins the inner periphery of the honeycomb body 1 and the outer periphery of the outer cylinder 2.

The honeycomb body 1 is made up of a thin metal flat foil 5 and a corrugated foil 6 having heat resistance and corrosion resistance. As shown in FIG. Is wound in a spiral shape while applying a load W to the back while applying a back tension, so that the peaks and valleys of the corrugated foil 6 and the flat foil 5 are brought into close contact with each other. At this time, a bonding inhibitor containing a high-melting-point oxide is applied to the surface (at least the peak) of the corrugated foil 6 in a range corresponding to the non-bonded portion 3 of the honeycomb body 1 by a coating means such as a roll coater device 7 or a brush. Apply with. The outer peripheral length of the honeycomb body 1 is 1 to 1 from the final dimension.
It is preferable to increase the size by about 2%. Further, when joining with the outer cylinder is performed by brazing, it is preferable to attach a brazing material within the range of the non-joining portion 3.

The outer cylinder 2 is a cylindrical body made of a metal having corrosion resistance and heat resistance. The outer cylinder 2 is manufactured with a longer circumference than the honeycomb body 1 so that the honeycomb body 1 can be easily inserted into the outer cylinder 2. . The outer cylinder 2 into which the honeycomb body 1 has been inserted is reduced in diameter by a tube reducing means to be processed to a predetermined size, and at the same time, the honeycomb body 1 is swaged.

[0013] The outer cylinder 2 containing the honeycomb body 1 in this manner is placed in a vacuum furnace at a temperature of 1100 to 1300 ° C for 10 minutes to
The honeycomb body is heated in a range of 3 hours, and the entire portion of the honeycomb body except for the non-contact portion is diffused and joined to form a rigid structure, and at the same time, the outer cylinder-honeycomb body is joined at a predetermined portion.

The non-joined portion 3 provided in the honeycomb body 1 has one to four layers (a layer in the axial direction in which the flat foil and the corrugated foil are interposed between the flat foil and the corrugated foil) inside the outermost periphery 8 of the honeycomb body. Is formed only in one layer. FIG. 2 is an enlarged view of a portion A in FIG. 1, wherein a flat-corrugated foil contact portion is bonded 9 to the first and second layers from the outer peripheral portion 8, but the non-bonded portion 3 is provided in the third layer. In the figure, the flat foil 5 and the corrugated foil 6 of the non-joined part 3 are exaggerated for easy understanding.
Are shown in a separated state, but the present invention is not limited to such a situation, and the two foils 5 and 6 may be in contact with each other and may be in a non-bonded state. The non-joined portion 3 is formed leaving a predetermined length Y in the axial direction from the upper end surface or the lower end surface of the honeycomb body 1. That is, the reason why the Y portions are joined is that if the entire length in the axial direction including the Y portions is made to be the non-joined portions, they are extruded and deformed by the exhaust gas flow.

The non-joined portion 3 is provided within four layers from the outer periphery because the outer tube 2 and the honeycomb body 1 have a rigid structure in which all the members are rigidly joined in the radial direction. Is concentrated near the outer periphery 8 of the honeycomb body to be joined to the outer cylinder. Therefore, if the non-joined portion 3 is provided within the four layers, which is the concentrated portion, the stress is sufficiently reduced. Because you can. Non-joined part 3
The reason why one layer is used is that one layer is sufficient for thermal stress relaxation, and if many layers are provided, the strength of the honeycomb body itself is affected and durability is deteriorated.

The joint portion 4 between the outer cylinder 2 and the honeycomb body 1 is within the range of the honeycomb body non-joined portion 3 so as not to have a rigid structure in which the outer cylinder 2 and the honeycomb body 1 are integrally joined in the radial direction. At an appropriate axial length. By locating the joints 4 in this manner, the degree of freedom of radial and axial expansion of the honeycomb body is maintained. The joining method may be either brazing or diffusion joining. In the case of diffusion bonding,
An anti-joining agent is applied to other non-joined portions.

[0017]

As described above, according to the present invention, the bonding structure capable of relaxing the thermal stress can be manufactured by simple diffusion bonding, and the number of non-bonding portions is one, so that the number of processing steps and costs can be reduced. In addition, since the metal carrier is almost entirely bonded, even if a misfire or the like occurs in the honeycomb body, the possibility of the honeycomb body falling off is small, and excellent durability is obtained even when the honeycomb body is formed thin. maintain.

[Brief description of the drawings]

FIG. 1 is a longitudinal sectional view schematically showing an example of the present invention.

FIG. 2 is an enlarged explanatory view of a portion A in FIG. 1;

FIG. 3 is an explanatory view showing a manufacturing example of the honeycomb body of the present invention.

[Explanation of symbols]

 1: Honeycomb body 2: Outer cylinder 3: Non-joined part 4: Joined part 5: Flat foil 6: Corrugated foil 7: Roll coater device 8: Outer peripheral part 9: Joined part

Claims (3)

(57) [Scope of request for utility model registration] 1. A flat foil and a corrugated foil made of metal are wound around one another,
In a metal carrier in which a honeycomb body formed in a spiral shape and laminated is housed in a metal outer cylinder and a flat foil-corrugated foil contact portion of the honeycomb body is joined, one to four inner layers from the outermost periphery of the honeycomb body are provided. The metal is characterized in that a portion other than the vicinity of the upper end portion or the lower end portion thereof is not joined to one layer between them, and the outer periphery of the honeycomb body and the inner periphery of the outer cylinder are joined within the range of the unjoined portion. Carrier. 2. The metal carrier according to claim 1, wherein a flat foil-corrugated foil contact portion of the honeycomb body is bonded by diffusion. 3. The metal carrier according to claim 1, wherein the outer periphery of the honeycomb body and the inner periphery of the outer cylinder are brazed or diffusion-bonded.