JPH07171419A - Metallic carrier - Google Patents

Abstract

PURPOSE:To absorb and relax the thermal stress at each of the ends of stacks and to improve the durability of the metallic honeycomb body of this carrier by forming each of the stacks of flat-sheetlike band materials and/or corrugated-sheetlike band materials each of which has a hole part on the abutting part in the metallic carrier for carrying an automobile exhaust gas purifying catalyst. CONSTITUTION:The X-lap type metallic honeycomb body XH is manufactured by stacking flat sheetlike band materials and corrugated-sheetlike band materials, both of which are made of thin metal sheets, one by one alternately up to desired stages to form at least three, plural stacks (e.g. X1' to X4', each of which is referred to as X1), abutting the stacks on each other at one end of each of the stacks by using jigs, etc., and then winding each of the stacks in the same direction with the abutted part as the center to form an abutted body. At this time, each of the stacks, i.e., the stack X1 is formed so as to provide it with the hole part A which has its opening on the side to be abutted and extends through the stack X1 in the vertical direction to the surface of the stack X1. Thus, a hollow space having a desired volume is formed in the axial central part of the honeycomb body XH to inhibit the telescoping phenomenon that the central part slides out to the outside due to the thermal stress at the time of using the honeycomb body XH of the objective carrier from occurring.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention generally relates to a honeycomb structure made of metal (hereinafter referred to as metal) for carrying an exhaust gas purifying catalyst which is used as an exhaust gas purifying means for automobiles by being inserted in an exhaust system. A honeycomb body) as a main constituent element.

More specifically, the present invention has, as a metal carrier, an X-wrap type metal honeycomb body for carrying an exhaust gas purifying catalyst as a main constituent element, and a central portion of the metal honeycomb body. An object of the present invention is to provide a metal carrier having improved durability.

[0003]

2. Description of the Related Art Conventionally, as a vehicle type exhaust gas purifying apparatus, a ceramic monolith type carrier has been used as a honeycomb structure carrier for carrying an exhaust gas purifying catalyst (Pt, Pd, Rh, etc.). Instead, the metal monolith type is attracting attention. Generally, a metal carrier (MS, metal substrate) for supporting a metal monolith type exhaust gas purifying catalyst is
A number of axial exhaust gas passages made by stacking flat plate and corrugated strips of heat-resistant thin steel plates so that they are in contact with each other Of a wound-type metal honeycomb body having a mesh-shaped ventilation passage (cell), and a tubular metal casing with both ends open for packing and fixing the honeycomb body inside Is. By the roll forming of the flat plate-shaped strip material and the corrugated plate-shaped strip material, a large number of mesh-like ventilation passages (cells) serving as exhaust gas flow passages are automatically formed.

In the above-mentioned conventional metal carrier composed of a wound type metal honeycomb body and a metal casing, the wound type metal honeycomb body and the metal casing are heated to a high temperature of the exhaust gas itself and the exhaust gas. Firmly fixed by brazing or welding so as to withstand the thermal expansion and thermal stress that occur in a high temperature atmosphere due to the exothermic reaction with the exhaust gas purification catalyst, and also to withstand the severe vibration when driving a car. To be done. Further, it goes without saying that the abutting portions of the flat plate-shaped band member and the corrugated plate-shaped band member forming the metal honeycomb body are also fixed by various methods such as brazing and welding.

Although the wound-type metal honeycomb body constituting the above-mentioned metal carrier is superior to the ceramic monolith-type one in various respects, it has a large thermal stress generated under the severe thermal conditions. On the other hand, there is still room for improvement. In particular, since excessive thermal stress concentrates and accumulates on the outer peripheral portion of the metal honeycomb body that is in contact with the inner wall surface of the metal casing and the vicinity thereof, the flat plate-shaped strip material or corrugated plate-shaped strip material forming the metal honeycomb body is Buckling, damage and cracking will reduce durability.
This is because the outer peripheral portion of the metal honeycomb body that comes into contact with the inner wall surface of the metal casing is composed of a set of flat plate-shaped strips and corrugated plate-shaped strips, and the set of strips is inside the metal casing. This is because they are in contact with each other along the wall surface, that is, they are joined in a planar manner, and the thermal stress generated inside the metal honeycomb body cannot be sufficiently absorbed and relaxed.

Recently, in place of the above-mentioned spiral-wound type metal honeycomb body, a minimum constituent unit constituting the metal honeycomb body, that is, a pair of flat plate-shaped strip material and corrugated plate-shaped strip material in abutting relationship In such a minimum structural unit, a metal honeycomb body having a structure in which each end of the minimum structural unit is in contact with the inner wall surface of the metal casing has been proposed. For example, as a metal honeycomb body having the above-mentioned structure, Japanese Patent Laid-Open No. 62-2
73051, Special Publication 3-502544, Special Publication 3-
No. 502660, Japanese Patent Laid-Open No. 4-227855, etc.
Character-shaped, bead-shaped, and X-wrap (swastika) type honeycomb bodies have been proposed.

The above-mentioned S-shaped type or X-wrap type metal honeycomb body is superior to the conventional spiral wound type honeycomb body. This is because in the conventional wound type honeycomb body, the end of one minimum constitutional unit composed of a set of flat plate-shaped strip and corrugated plate-shaped strip is on the inner wall surface of the metal casing as described above. While abutting along each other, since each end of a predetermined number of minimum constituent units abuts the inner wall surface of the metal casing, thermal stress can be absorbed and relieved at each end. This is because the durability of the body can be improved.

[0008]

In the various types of metal honeycomb bodies other than the wound type constituting the above-mentioned metal carrier, particularly in the X-wrap type metal honeycomb body, the durability of the outer peripheral portion is as described above. Although improved, it is required to improve the durability of the central portion of the metal honeycomb body in relation to it.

As will be described later, this is because the X-wrap type metal honeycomb body has at least three stacks formed by alternately stacking flat plate-shaped strips and corrugated strip-shaped strips in a desired number of steps at one end. In the above, there is a deep relationship with the manufacturing in which the stacks are abutted against each other and the respective stacks are wound in the same direction around the corresponding contact portion. Then, a large deformation force based on thermal stress is applied to the center portion of the metal honeycomb body manufactured as described above, and the center portion is telescoping phenomenon (the center portion is outside due to the deformation force based on thermal stress). Pile-out phenomenon (also called film-out) occurs, and each stack separates, or deformation of the central member (flat plate and corrugated strip) in conjunction with the telescoping phenomenon. Buckling, cracking and damage are induced, and its durability is greatly impaired.

As described above, in improving the durability of the central portion, the phenomenon (telescoping, film-out) of the central portion of the metal honeycomb body protruding outward (in the axial direction of the metal honeycomb body) is prevented or suppressed. Is a big challenge. In addition, deformation, buckling, cracking, breakage, and the like of the strip material (flat plate strip material and corrugated strip material) that composes the metal honeycomb body are induced in conjunction with the telescoping phenomenon. How to reduce should also be considered.

The main cause of the deterioration of the durability of the central portion of the metal honeycomb body is the deformation force due to the large thermal stress applied to the central portion of the metal honeycomb body. It is how to take measures to absorb and mitigate the thermal stress of. The present inventors
-Detergent studies were carried out on measures for improving the durability of the lap-type metal honeycomb body, particularly the durability of the central portion.

As a result, a desired number of stacks (X _{1 to} X _n , n is 3 or more) are formed by alternately laminating flat plate-shaped strips and corrugated strips made of heat-resistant thin metal plates. When manufacturing an X-wrap type metal honeycomb body, the stack (X) having a hole portion penetrating in the vertical direction of the stack (X) is used as the stack (X). At that time, it was found that the thermal stress in the central portion can be effectively absorbed and relaxed.

Further, in this type of X-wrap type metal honeycomb body, in the context of the above-mentioned manufacturing process, the processing stress is concentrated in the central portion of the stack, so that in the central portion of the metal honeycomb body, the corrugated plate material It has been found that the uniform cell can be obtained by using the stack having the above-mentioned structure, though the waveform is broken and it is difficult to manufacture the uniform cell. Further, when a metal honeycomb body is manufactured by using the stack having the above-mentioned structure, a space portion having a desired volume is formed in the axial central portion of the metal honeycomb body, so that the exhaust gas is agitated and mixed in the space portion. It was found that the advantages of uniform exhaust gas purification capacity and improved purification rate can also be obtained.

The present invention has been completed based on the above-mentioned findings, and the present invention provides a metal carrier having an X-lap type metal honeycomb body excellent in exhaust gas purification performance and durability as a main constituent element. Will be provided.

[0015]

SUMMARY OF THE INVENTION The present invention will be described in brief. The present invention provides at least three stacks formed by alternately laminating flat band-shaped strips and corrugated plate-shaped strips made of thin metal plates in a desired number of stages. (X _{1 to} X _n , n is an integer of 3 or more) are used to bring the stacks (X _{1 to} X _n ) into contact with each other at one contact end, and the contact ends are centered. An X-wrap type metal honeycomb body (XH) for supporting an exhaust gas purifying catalyst, which is manufactured by winding in the same direction, and the above X-
A metal carrier comprising a metal casing for accommodating a wrap type metal honeycomb body (XH),
Wherein each stack (X ₁ ~X _n) is, it is composed of flat strip and / or corrugated strip having a hole in the contact end portion, to a metal carrier, wherein .

Hereinafter, the technical constitution and embodiments of the present invention will be described in detail with reference to the drawings. Needless to say, the present invention is not limited to the illustrated one.

As described above, the present invention is characterized in that the characteristics of the metal honeycomb body, which is a main constituent element of the metal carrier, are improved particularly in the X-wrap type metal honeycomb body.

The outline including the manufacturing process of the conventional metal honeycomb body of the X-wrap type is shown in FIGS. That is, FIG. 8 shows four stacks (X ' ₁ ~
_X'4) shows a front view of the metal honeycomb body X- lap type manufactured using (XH) and FIG. 9 is the metal honeycomb body (XH) 1 single stack is subjected to produce the ( X ′ ₁ ) is a perspective view, and FIG. 10 is a perspective view of the metal honeycomb body (XH) used for manufacturing the metal honeycomb body (XH).
One of a diagram for explaining the abutting relationship of the stack _(X'1 ~X' _4), FIG. 11 is an enlarged view of the central portion of the metal honeycomb body (XH).

The shape structure of the X-wrap type metal honeycomb body (XH) according to the present invention is not limited to that shown in FIG. 8, but the one disclosed in, for example, Japanese Patent Application Laid-Open No. 4-227855 is applicable. That is, each of the stacks (X ₁ -X ₁ ) forming the X-wrap type metal honeycomb body (XH) is
By changing the front (cross-section) shape of X _n ) and the setting method of the abutting end, not only the circular front shape shown in FIG. The target is the metal honeycomb body. In particular, in the present invention, the abutting end portion includes not only the literal end surface portion of each stack, but also the end surface portion and its vicinity in the arrangement relationship of other stacks. In the art, as shown in FIGS. 8 and 11, in this type of metal honeycomb body, the contact state at the contact end of each stack is X-shaped or swastika-shaped. It is commonly known as a wrap type or a swastika type.

More specifically, the above-mentioned X-wrap type metal honeycomb body (XH) includes (a) a flat metal strip (1) and a corrugated strip (2) made of a thin metal plate. At least two or more stacks are formed by stacking the stacks in a desired number of steps, and (b) the stacks are brought into contact with each other at their one ends using a desired jig or the like. The stack is manufactured by a manufacturing process in which the contact bodies are wound around the respective contact parts in the same direction. A jig having a desired structure suitable for holding or sandwiching one end of each stack used in the step (b) is an X-wrap type in which each stack is wound around the jig in the same direction. After the metal honeycomb body (XH) is manufactured, it may be removed or integrated with the metal honeycomb body (XH). In addition, flat strip (1)
By forming a stack from the corrugated strip material (2) and then winding and forming, a large number of cells (3) which become exhaust gas passages are automatically formed as shown in the figure. 8 has four stacks (X ′ _{1 to} X ′ at the stage (a).
₄ ) is formed, and one end of each stack is moved to 90 at the stage of (b).
The X-wrap type metal honeycomb body (XH) was formed by abutting at an intersecting angle of 10 ° (see FIG. 10) and winding-molding at the stage of (C).

As described above, the X-wrap type metal honeycomb body has improved durability, particularly the durability of the outer peripheral portion, as compared with, for example, a wound type metal honeycomb body. However, in contrast to the durability of the outer peripheral portion, conversely, improvement of the durability of the central portion is strongly demanded. In particular, in the X-wrap type metal honeycomb body, the durability of the center portion is more strongly required than other metal honeycomb bodies due to the arrangement structure of each stack in the center portion. Further, in the X-wrap type metal honeycomb body, as can be seen from the above-described manufacturing example, a desired number of stacks (X) formed by alternately laminating a flat plate-shaped strip material and a corrugated plate-shaped strip material in a desired number. When the rolls are formed in the same direction, a large processing stress is applied to the strip material (flat strip material and corrugated strip material) at the relevant contact end, which is the center of processing, causing a large deviation from each other and causing a flat sheet shape. A region in which the corrugated strip is not present is formed between the strip and the flat strip, or the corrugation of the corrugated strip is deformed in association with the deviation. These are major negative factors in manufacturing a metal honeycomb body having a uniform cell shape and cell density. Needless to say, these may cause a non-uniform distribution of the amount of catalyst supported in the metal honeycomb body, and thus a non-uniform purifying ability.

According to the present invention, in order to improve the center portion of a metal honeycomb body of X-wrap type and to eliminate the drawbacks resulting from the manufacturing process, the position of the stack (X) at the abutting end portion side is also improved. Stack (X) using a flat strip and / or a corrugated strip having a hole in the part
Adopt the technical configuration of configuring. By adopting the above-mentioned technical configuration, the X-wrap type metal honeycomb body has a desired space space in the central portion in the axial direction. Therefore, the deforming force based on the large thermal stress in the axial direction can be divided in the space portion, and the telescoping phenomenon can be effectively prevented. In addition, since the strips constituting each stack have holes at the portions where the processing stress is concentrated, the respective stacks are smoothly rolled and formed, so that the corrugated strips due to the application of the processing stress are formed. It is possible to manufacture a metal honeycomb body having uniform cells in which the waveform deformation is prevented. Hereinafter, specific embodiments of the technical configuration of the present invention will be described.

FIG. 1 is a perspective view of a stack (X ₁ ) having holes (A) of the first embodiment used for manufacturing an X-wrap type metal honeycomb body. Incidentally, FIG. 1 corresponds to FIG. 9 showing the above-mentioned conventional stack (X ′ ₁ ). Stack of the present invention (X ₁ )
Is greatly different from the conventional one in that it has a hole (A) that is opened on the contact portion side of the stack and penetrates vertically. To construct the stack (X ₁ ) of FIG. 1, the strips shown in FIG. 2 may be used. That is, the flat plate-shaped strip (1) having the hole (a) shown in FIG. 2A and the corrugated plate-shaped strip (2) having the hole (a) shown in FIG. The stack (X ₁ ) may be formed by alternately stacking. Needless to say, the holes (a) of both strips (1, 2) form the holes (A) of the stack (X ₁ ).
FIG. 3 is an X-wrap type of the stack (X ₁ ) shown in FIG. 1 and manufactured by roll molding (see the manufacturing process shown in FIGS. 8 to 11 described above) according to a conventional method. FIG. 2 is a cross-sectional view taken along the line I-I of FIG. 1 in the metal honeycomb body. It shows that a desired volume of space space (SP) is formed in the axial direction (direction perpendicular to the paper surface) of the metal honeycomb body (XH).

In the present invention, the flat strip material (1) used for producing the X-wrap type metal honeycomb body is used when producing a usual metal monolith type honeycomb body. Strip material, such as chrome steel (chrome 13% to 25%), Fe-Cr 20%-
Heat resistant stainless steel such as Al 5%, or heat resistant stainless steel in which rare earth metal (REM) is added to improve high temperature oxidation resistance, thickness of 0.04 mm ~
A strip of 0.1 mm is used. Also, the band material on the corrugated plate (2)
Is a predetermined substantially sine wave from the flat strip (1),
What is corrugated so as to have a substantially triangular wave or a substantially trapezoidal wave is used. The flat strip (1) and the corrugated strip (2) containing Al, or the surface of which an Al layer is provided, are heat-treated to form whiskers or mushrooms on the surface. Alumina (Al ₂ O
What precipitated ₃ ) is preferable. The whisker-like alumina is preferable because it can firmly hold the washcoat layer for carrying the exhaust gas purifying catalyst such as Pt, Pd, and Rh.

In the present invention, the X-wrap type metal honeycomb body is used by being packed and fixed in a metal casing (C) as shown in FIG. As the material of the metal casing (C) described above,
The same kind of heat-resistant steel as that of the strips (1, 2) forming the metal honeycomb body may be used, or one having a high heat-corrosion resistance may be used. In addition, a double structure with the outer part of the metal material richer in heat resistance and corrosion resistance than the inner part, specifically, one using ferritic stainless steel for the inner part and austenitic stainless steel for the outer part is used May be.

FIG. 4 is a perspective view of a stack (X ₁ ) having holes (A) of the second embodiment used for manufacturing the metal honeycomb body of the present invention. The major difference from the first embodiment is that it does not have an opening on the abutting end side, but has a hole (A) penetrating in the vertical direction at a desired distance (d) from the abutting end. ), And other configurations are the same. Stack (X ₁ ) of the second embodiment
5A and 5B, the flat plate-shaped band member and the corrugated plate-shaped band member shown in FIGS. The stack of the second embodiment is firmly fixed to each other by the amount that it does not have an opening at the contact end, but the effect of absorbing and relaxing thermal stress is reduced depending on the setting of the interval (d). . Therefore, the interval (d) may be appropriately determined in consideration of the above points.

FIG. 6 is a plan view of a stack (X ₁ ) having holes (A) of a third embodiment used for manufacturing the metal honeycomb body of the present invention. In the third embodiment, compared with the first embodiment, the hole (A) has a semi-elliptical shape instead of a rectangular shape in plan view. In such a case, it is possible to avoid stress concentration on the corners of the holes, and thus it is possible to further improve durability.

FIG. 7 is a sectional view of a stack (X ₁ ) having holes (A) of the fourth embodiment used for manufacturing the metal honeycomb body of the present invention. The fourth embodiment is different from the first embodiment in that another stack (X ₂ ) is arranged in the hole (A). As the other stack (X ₂ ), one having a small cell density is arranged as shown in the drawing. Considering that the flow velocity distribution of the exhaust gas flow is faster in the central portion of the metal honeycomb body than in other portions, the stack (X ₁ +
Since the amount of the catalyst carried in the central portion can be increased by using X ₂ ), the exhaust gas purifying ability can be made equal to that of the other portions.

Although not shown, the stack (X) used for producing the metal honeycomb body of the present invention is limited to the one having a hole (A) penetrating in the vertical direction as shown in the above embodiment. Not done. Either one of the flat plate-shaped strip and the corrugated strip-shaped strip having a hole (a) as shown in FIG. 2 at a portion corresponding to the hole (A) is stacked (X It is needless to say that the above may be configured.

[0030]

In the metal carrier of the present invention, an X-wrap type metal honeycomb body, which is a main component of the metal carrier, is formed by alternately laminating flat strips and corrugated strips in a desired number of stages. Use at least two stacks (X),
The stacks are manufactured by abutting each of the stacks at one end at the contact end and winding the stacks in the same direction around the contact end. Is characterized by using a flat strip and / or a corrugated strip having a hole of a desired size and a desired shape on the contact end side. Therefore, since the X-wrap type metal honeycomb body of the present invention uses the stack (X) having the above-mentioned configuration, it has a desired volume of space in the axial central portion of the metal honeycomb body.

Therefore, in the space, the deformation force due to the large thermal stress generated in the central portion of the honeycomb body can be effectively divided in the axial direction, so that the telescoping phenomenon is prevented and the telescoping phenomenon is prevented. Deformation, buckling, cracking, breakage, etc. of the belt material linked with are prevented.

Further, since the exhaust gas flow is effectively agitated and mixed in the space, the purification rate of the exhaust gas can be increased. Furthermore, when manufacturing an X-wrap type metal honeycomb body from the stack (X) by winding molding, a strip material (a flat strip material and / or a corrugated strip material)
However, since it has a hole at the abutting end of each stack to which a large processing stress is applied, it can be smoothly rolled and formed, so that the waveform of the corrugated strip is less likely to be deformed into a uniform cell shape,
It is possible to provide a metal honeycomb body having a uniform cell density.

[Brief description of drawings]

FIG. 1 is a perspective view of a stack (X ₁ ) according to a first embodiment.

FIG. 2 is a diagram illustrating a pair of flat plate-shaped strips and corrugated plate-shaped strips that constitute the stack (X ₁ ) of the first embodiment.

FIG. 3 is a diagram illustrating a space space (SP) at a central portion in the axial center direction of a metal honeycomb body manufactured by using the stack (X ₁ ) of the first embodiment.

FIG. 4 is a sectional view of a stack (X ₁ ) according to a second embodiment.

FIG. 5 is a diagram illustrating a pair of flat plate-shaped strips and corrugated plate-shaped strips that form a stack (X ₁ ) of a second embodiment.

FIG. 6 is a plan view of a stack (X ₁ ) according to a third embodiment.

FIG. 7 is a sectional view of a stack (X ₁ ) according to a fourth embodiment.

FIG. 8 is a front view in which a part of an X-wrap type metal honeycomb body is omitted.

FIG. 9 is a perspective view of a stack (X ′ ₁ ) used for manufacturing a conventional X-wrap type metal honeycomb body.

FIG. 10 shows stacks (X ′ _{1 to} X ′) in a conventional manufacturing process of an X-wrap type metal honeycomb body.
It is a figure explaining the contact relationship of ₄ ).

FIG. 11 is an enlarged front view of a central portion of a conventional X-wrap type metal honeycomb body.

[Explanation of symbols]

MS ......... metal carrier XH _1, XH '......... metallic honeycomb body C ......... stack _X'1 metal casing X ₁ ......... present _{invention, X'2, X'3, X'} 4 ......... Conventional stack 1 ……… Flat plate strip 2 ……… Corrugated strip strip 3 ……… Cell (mesh-like vent passage)

Claims (7)

[Claims] 1. At least three stacks (X _{1 to} X _n , n is an integer of 3 or more) formed by alternately laminating flat plate-shaped strips and corrugated strips made of thin metal plates in a desired number of stages. use,
Wherein is brought into contact with each other in the abutting end portions of the one end of each stack (X ₁ ~X _n), the abutting end center for carrying the fabricated exhaust gas purifying catalyst wound in the same direction A metal carrier comprising an X-wrap type metal honeycomb body (XH) and a metal casing for housing the X-wrap type metal honeycomb body (XH), wherein each of the stacks (X _{1 to} X _n ) Is composed of a flat plate-shaped band member and / or a corrugated plate-shaped band member having a hole portion on the contact end side, and a metal carrier. 2. Each of the stacks (X _{1 to} X _n ) has a hole penetrating in the up-down direction of each stack which is not open at the contact end, in the vicinity of the contact end. 1. The metal carrier according to 1. 3. The metal carrier according to claim 1, wherein each of the stacks (X _{1 to} X _n ) has a hole that is open to the contact end side and that penetrates each stack in the vertical direction. 4. The metal carrier according to claim 2, wherein the through hole has a desired shape. 5. The metal carrier according to claim 2, wherein each of the stacks (X _{1 to} X _n ) has a hole portion, and the hole portion accommodates another stack. 6. The metal carrier according to claim 1, wherein only the flat plate-shaped strip material forming each stack (X _{1 to} X _n ) has a hole at the abutting end. 7. The metal carrier according to claim 1, wherein only the corrugated strip material forming each stack (X _{1 to} X _n ) has a hole at the abutting end.