JPH07171418A - 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 by arranging a shape retaining jig in the vicinity of the abutting part of the stack 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), 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, e.g. the stack X1 is provided with a shape-retaining jig consisting of a cylindrical pin to improve its shape retention and the located position of the shape-retaining jig (the distance from the end to be abutted d2) is determined by taking the thickness d3 of the stack X1 and the diameter d1 of the shape-retaining jig T, etc., into consideration. Thus, the thermal stress at each of the ends of the stacks is effectively absorbed and relaxed.

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 relates to an X-wrap which has a particularly uniform cell shape formed between a flat strip and a corrugated strip, has a constant cell density, and is excellent in durability. The present invention relates to a metal carrier whose main component is a metal honeycomb body of a type.

[0003]

2. Description of the Related Art Conventionally, in a vehicle exhaust gas purifying apparatus of this type, 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 purification catalyst.
Is a stack of heat-resistant thin steel plate flat strips and corrugated strips that come into contact with each other, and are spirally formed in a batch to form an exhaust gas passage in the axial direction. Of a winding type metal honeycomb body having a large number of mesh-like ventilation holes (cells), and a tubular metal casing having both ends opened for fitting and fixing the honeycomb body inside. It is something. 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 abuts 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 seated. Bow or
It causes damage or cracks and reduces durability. This is because the outer peripheral portion of the metal honeycomb body that abuts the inner wall surface of the metal casing is composed of a pair of flat plate-shaped strips and corrugated strips, and the set of strips is the inner wall surface of the metal casing. This is because they are in contact with each other along, that is, they are joined in a plane shape, 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 structure, Japanese Patent Laid-Open No. 62-273
051, Special Publication 3-502544, Special Publication 3-50
No. 2660, Japanese Patent Application Laid-Open No. 4-227855, and the like, S-shaped type, tongue-shaped type, and X-wrap (swastoid) type metal 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, each end of a predetermined number of minimum constituent units abuts on the inner wall surface of the metal casing, so that each end can absorb and relieve thermal stress. This is because the durability of the honeycomb body can be improved.

[0008]

However, 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, in view of the manufacturing process, a flat plate shape is obtained. The shape of a large number of mesh holes (cells), which are exhaust gas passages formed between the strip material and the corrugated strip material, becomes non-uniform, and the initially designed metal honeycomb body with a desired cell density is manufactured. Therefore, there is a drawback that a catalytic converter having an exhaust gas purifying ability as designed cannot be obtained. That is, due to the deformation of the cells, defects such as non-uniformity of the catalyst supporting area (amount) between predetermined portions inside the metal honeycomb body and non-uniformity of the back pressure resistance are brought about.

In addition, since the central portion of the X-wrap type metal honeycomb body is exposed to the highest temperature region during use, which induces a large thermal stress, the central portion structure is made more durable. It has to be done, but the conventional one leaves room for improvement. More specifically, the deformation force due to a large thermal stress causes the phenomenon that the center part pops out (scoping, film out), but in conjunction with this, peeling between the stacks and the metal honeycomb structure are formed. The strip material (flat plate and / or corrugated strip material) is deformed, buckled, cracked, or damaged, and the durability is impaired.

The present inventors have diligently studied how to solve the above-mentioned drawbacks of the X-wrap type metal honeycomb body. As a result, a stack (X _{1 to} X _n , n is an integer of 3 or more) formed by alternately stacking flat plate-shaped strips and corrugated strips made of heat-resistant thin metal plates X-wrap manufactured by using the above-mentioned stack (hereinafter, represented by X as a representative) to abut on each other at abutting end portions of one end and to wind in the same direction around the abutting end portions. In the metal honeycomb body of the type (XH), the processing stress applied during the roll forming induces the mutual displacement of the strips forming each stack (X) and the deformation of the corrugated strip. It has been found that the abovementioned drawbacks are effectively eliminated if a restraining measure is taken on each stack (X).

It has also been found that the suppressing means has a sufficient effect in reinforcing the central portion of the metal honeycomb body. The present invention has been completed based on the above findings, and the present invention provides a metal carrier having excellent exhaust gas purification performance and durability.

[0012]

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, and the stacks are brought into contact with each other at their abutting end portions, and the stack is formed in the same direction around the abutting end portion. An X-wrap type metal honeycomb body for carrying an exhaust gas purifying catalyst having a structure in which the end portions of each flat plate-shaped strip member and corrugated plate-shaped strip member of each stack are in contact with an inner wall surface of a metal casing (XH), and a metal casing for accommodating the metal honeycomb body (XH), wherein each of the stacks (X _{1 to} X _n , n is an integer of 3 or more) has the contact end. Consists of a shape retention jig placed near the The present invention relates to a metal carrier characterized by the above.

The technical construction and substantive aspects of the present invention will be described below 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, among the metal honeycomb bodies having various structures, the X-wrap type metal honeycomb body is particularly improved.

The outline including the manufacturing process of the X-wrap type metal honeycomb body is shown in FIGS. That is, FIG. 10 shows a front view of an X-wrap type metal honeycomb body (XH), and FIG. 11 shows four stacks (X _{1 to} X ₄ ) used to manufacture the metal honeycomb body (XH). ), And shows the state of being abutted at the abutting end of one end of each stack, and FIG.
The enlarged front view of the center part of the lap type metal honeycomb body (XH) is shown. In the art, as shown in FIG. 12, in this type of metal honeycomb body, the contact state at the contact end of each stack is an X shape or a swastika shape, and therefore, it is an X-wrap type or swastika type. It is commonly known as a type. In addition, in FIGS. 10 to 12, a part of the configuration is omitted for the sake of clarity.

As shown in the figure, the X-wrap type metal honeycomb body (XH) has a set of a flat plate-shaped strip (1) and a corrugated plate-shaped strip (2) made of thin steel plates as a minimum structure. It is manufactured as a unit. That is, as shown in FIG. 11, a set of flat plate-shaped strips (1) and corrugated plate-shaped strips (2) are laminated at a desired stage to form a stack (X _{1 to} X ₄ ). Next, the stacks (X _{1 to} X ₄ ) are brought into contact with each other at the abutting end portions of one end of each stack, and the stacks (X ₁
To X ₄ ) are wound in the same direction (for example, clockwise direction) to manufacture the X-wrap type metal honeycomb body (XH) shown in FIG. 10. When the stack (X) is roll-molded, a roll-molding jig having a desired structure suitable for holding or sandwiching one end of each stack may be used. Then, after stacking each stack around the jig in the same direction to produce an X-wrap metal honeycomb body (XH), the jig may be removed or the metal honeycomb body (XH ) May be integrated.

As can be seen from the above-mentioned manufacturing example of the X-wrap type metal honeycomb body (XH), in the set of flat plate-shaped strip and corrugated plate-shaped strip which are the minimum constitutional units of the stack (X), The flat strips and the corrugated strips are alternately brought into contact with each other, and the stacks (X) are formed by stacking these at desired stages, and the stacks (X) are brought into contact with each other in the next step, and the X-wrap When a roll-shaped structure is wound and formed, a large processing stress is applied to each minimum structural unit, causing a large deviation from each other, and a corrugated strip exists between the flat strip and the corrugated strip. Areas that are not to be formed are formed, and the corrugation of the corrugated strip is deformed in association with the deviation. These make it difficult to manufacture a honeycomb body having a uniform cell shape and a predetermined cell density. Further, the corrugated deformation of the corrugated strip material makes the amount of catalyst carried per unit volume non-uniform or the back pressure resistance non-uniform between predetermined portions inside the metal honeycomb body.

In the present invention, in order to solve the above-mentioned drawback, each stack (X _{1 to} X _n ) maintains its shape at the time of roll forming, more specifically, each stack (X). The technical configuration of arranging a shape-retaining jig is adopted. Hereinafter, a specific mode will be described with reference to the drawings.

FIG. 1 shows the shape retention of one stack (X ₁ ) formed by alternately laminating flat band-shaped strips and corrugated strips made of heat-resistant thin metal plates in a desired number of stages. It is a figure explaining the 1st embodiment of the jig for shape retention applied in order to improve the nature. In the present invention, the first shape-retaining jig (T) is composed of a single cylindrical pin. As shown in the figure, the cylindrical pin (T) is arranged at a desired distance (d ₂ ) from the abutting end, and the thickness (d ₃ ) of the stack (X ₁ ) for shape retention. It may be appropriately determined in consideration of the diameter (d ₁ ) of the jig (T). If the distance (d ₂ ) becomes too large, the reinforcing effect of the central portion of the metal honeycomb body will be deteriorated.
As the cylindrical pin (T), it is possible to use a pin having a hardness that is slightly deformed with respect to the processing stress applied during the roll forming of the stack (X ₁ ). In this case, since the pin itself is also deformed during the roll forming, smooth roll forming of the flat strip and the corrugated strip is performed. It goes without saying that in the present invention, the cylindrical pin may be composed of two or more pins.

FIG. 2 is a view for explaining a second embodiment of the shape-retaining jig applied to the stack (X ₁ ). As shown in the drawing, the shape-retaining jig of the present invention is a solid body (T ₁ ) having no brim portion at the pin end portion, or a hollow body having no brim portion at the pin end portion. It may be (T ₁ ').

FIG. 3 is a view for explaining a third embodiment of the shape-retaining jig applied to the stack (X ₁ ). As shown in the figure, the shape-retaining jig of the present invention is a solid body (T ₁ ) having a brim portion at the pin end portion, or a hollow body (T ₁ 'having a brim portion at the pin end portion). ) May be sufficient.

FIG. 4 is a view for explaining a third embodiment of the shape-retaining jig (T) applied to the stack (X ₁ ). As shown in the figure, the shape-retaining jig of the present invention is composed of a wire instead of the above-mentioned cylindrical pin. The shape-retaining jig composed of the wire of the present invention is a stack (X
_As shown in the figure, it is provided around the outer periphery of the central portion of ₁ ) to bind and fix the stack members (a flat plate-shaped strip and a corrugated strip-shaped strip). As a result, the shape retention of the stack (X ₁ ) is achieved when the stack (X ₁ ) is roll-formed. In the present invention, although not shown, the wire may have a circular cross-sectional shape, a flat ribbon material, or another shape. It's ridiculous.

FIG. 5 is a view for explaining a fifth embodiment of the shape-retaining jig (T) applied to the stack (X ₁ ). 5A is a perspective view and FIG. 5B is a partial sectional view. A fifth embodiment of the present invention is a shape-retaining jig (T ₁ , T ₂ ) composed of two wires, which is not the peripheral type of the fourth embodiment but has a desired interval, It is arranged so as to penetrate the stack (X ₁ ). Both ends of the shape-retaining jig (T ₁ , T ₂ ) are arranged so as to sandwich the stack on the upper and lower surfaces of the stack (S ₁ ) as shown in the figure. It goes without saying that the directions of the both ends may be arranged at right angles to the illustrated one.

FIG. 6 is a view for explaining a sixth embodiment of the shape-retaining jig (T) applied to the stack (X ₁ ). 6A is a perspective view and FIG. 6B is a partial cross-sectional view. As shown in the figure, the sixth embodiment is a shape-retaining jig (T ₁ , T ₂ ) composed of two wires (however, T ₂ is omitted). As shown, each shape-retaining jig (T ₁ , T ₂ )
Are arranged so as to penetrate the stack, and are arranged on both side surfaces of the stack (X ₁ ) so that both ends thereof extend.

FIG. 7 is a view for explaining the seventh embodiment of the shape-retaining jig (T) applied to the stack (X ₁ ). 7A is a perspective view and FIG. 7B is a partial cross-sectional view. As shown in the figure, the seventh embodiment is similar to the sixth embodiment, in that the shape-maintaining jig (T ₁ ,
T ₂ ), (T ₂ is omitted). The arrangement method for the stack is only different from that of the sixth embodiment in that it has an inverse relationship.

FIG. 8 is a view for explaining the eighth embodiment of the shape-retaining jig (T) applied to the stack (X ₁ ). 8A is a perspective view and FIG. 8B is a sectional view. As shown in the figure, the eighth embodiment is a shape-retaining jig (T) composed of one wire, which is bored at a desired distance from both side surfaces of the stack (X ₁ ). Using the through hole, the jig (T) is inserted and arranged, and both ends of the jig (T) are arranged to face each other.

[0027] Figure 9 is a stack ninth embodiment of the (X ₁₎ to the applied shape-retaining jig (T) (T), your desired distance from both sides of the stack (X ₁₎ The jig (T) is inserted and disposed by using the through hole formed in the stack, and both ends of the jig (T) are arranged on the same outer surface of the stack, and the outer ends are It is arranged so as to extend in the direction of both sides of the stack.

In the present invention, the flat strip (1) used for producing the X-wrap type metal honeycomb body is used when producing a normal 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 rare earth metal (REM) for improving high temperature oxidation resistance
Heat-resistant stainless steel with a thickness of 0.04 mm
A strip of ~ 0.1 mm is used. As the corrugated strip material (2), the corrugated plate material (1) corrugated so as to have a predetermined substantially sine wave, substantially triangular wave or substantially trapezoidal wave is used. As the flat plate-shaped strip (1) and the corrugated strip-shaped strip (2), those strips (1, 2) containing Al or those having an Al layer on the surface are heat-treated. It is preferred that whisker-like or mushroom-like alumina (Al ₂ O ₃ ) is deposited on the surface thereof. The whisker-like alumina is P
This is preferable because the washcoat layer for supporting the exhaust gas purifying catalyst such as t, Pd, and Rh can be firmly held. Accordingly, in the present invention, each stack was the _{(X 1, X 2, ......} X n, n is an integer of 3 or more) shape-retaining jig applied to also, the same heat resistance and strip described above It is preferably composed of a material having

In the present invention, the X-wrap type metal honeycomb body is used by being filled and fixed in a metal casing. As the material of the metal casing described above, heat resistant steel of the same type as the band material (1, 2) forming the metal honeycomb resistance may be used, or a material having high heat and corrosion resistance may be used. Also, a double structure with the outer part of the metal material richer in heat resistance and corrosion resistance than the inner part, specifically, using ferritic stainless steel for the inner part and austenitic stainless steel for the outer part Good.

[0030]

The X-wrap type metal honeycomb body, which is the main constituent element of the metal carrier of the present invention, has a pair of flat plate-shaped strips and corrugated plate-shaped strips, which are the minimum constitutional units, at each end. The structure has a structure in which a portion abuts on the inner wall surface of a metal casing that is encased, and internal stress accumulated at the contact and the vicinity thereof can be absorbed and relieved at each end portion. Compared with the structure, it has a structure in which a pair of flat plate-shaped strips and corrugated plate-shaped strips are in contact with the inner wall surface of the outer metal casing.) It is excellent.

Furthermore, the present invention is based on the disadvantages found in this type of X-wrap type metal honeycomb body, namely the cells (mesh vents for exhaust gas passages) induced in connection with its manufacturing process. It eliminates the disadvantages of non-uniform shape of the road) and non-uniform cell density.

In the present invention, the above-mentioned drawbacks can be solved by applying a shape-retaining jig to a desired number of stacks used when manufacturing an X-wrap type metal honeycomb body. By applying the shape-retaining jig, another advantage can be obtained. That is, in this type of metal honeycomb body, the abutting end portions are separated from each other and separated from each other due to a large deformation force based on a large thermal stress during use, and further, the scoping (the center portion pops out). The film-out phenomenon occurs, and deformation, buckling, cracking, breakage, etc. of the strip (flat strip and / or corrugated strip) are induced in conjunction with the scoping. By applying a jig for separation, it is possible to effectively suppress the separation between the stacks and the scoping of the central portion. From the above, the present invention can provide a metal carrier having an X-wrap type metal honeycomb body as a main constituent element and excellent in various characteristics.

[Brief description of drawings]

FIG. 1 is a diagram illustrating a first embodiment of a shape-retaining jig applied to a stack.

FIG. 2 is a diagram illustrating a second embodiment of a shape-retaining jig applied to a stack.

FIG. 3 is a diagram illustrating a third embodiment of a shape-retaining jig applied to a stack.

FIG. 4 is a diagram illustrating a fourth embodiment of a shape-retaining jig applied to a stack.

FIG. 5 is a diagram illustrating a fifth embodiment of a shape-retaining jig applied to a stack. FIG. 5A is a perspective view, and FIG.
Is a partial cross-sectional view.

FIG. 6 is a diagram illustrating a sixth embodiment of a shape retention jig applied to a stack. FIG. 6A is a perspective view, and FIG.
Is a partial cross-sectional view.

FIG. 7 is a diagram illustrating a seventh embodiment of a shape-retaining jig applied to a stack. FIG. 7 (A) is a perspective view, (B)
Is a partial cross-sectional view.

FIG. 8 is a diagram illustrating an eighth embodiment of a shape-retaining jig applied to a stack. FIG. 7 (A) is a perspective view, (B)
Is a sectional view.

FIG. 9 is a diagram illustrating a ninth embodiment of a shape-retaining jig applied to a stack. FIG. 7 (A) is a perspective view, (B)
Is a sectional view.

FIG. 10 is a front view in which a part of an X-wrap type metal honeycomb body is omitted.

FIG. 11 is a perspective view of a stack (X ₁ ) used for manufacturing an X-wrap type metal honeycomb body.

FIG. 12 is an enlarged view of a central portion of an X-wrap type metal honeycomb body.

[Explanation of symbols]

1 ……… Plate-shaped strip 2 ……… Corrugated strip 3 ……… Cells (mesh-like vent holes) X ₁ , X ₂ , X ₃ ……… Stack XH ……… Metal honeycomb T, T ₁ , T ₁ ′, T ₂ ……… Shape retention jig

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,
The stacks are brought into contact with each other at the contact ends at one end, and the stacks are formed by winding in the same direction around the contact ends, and the end portions of the flat plate-shaped strips and corrugated strips of each stack are formed. X-wrap type metal honeycomb body (XH) for supporting an exhaust gas purifying catalyst having a structure of abutting against the inner wall surface of a metal casing that is enclosed by
H) a metal casing for accommodating the metal carrier, wherein each of the stacks (X _{1 to} X _n , n is an integer of 3 or more),
A metal carrier comprising a shape-retaining jig arranged near the contact end. 2. The metal carrier according to claim 1, wherein the shape-retaining jig is a pin arranged to penetrate each stack. 3. The metal carrier according to claim 1, wherein the shape-retaining jig is a wire penetrating each stack or a wire provided around the outer circumference of each stack. 4. The metal carrier according to claim 2, wherein the shape-retaining jig is composed of two or more pins. 5. The metal carrier according to claim 3, wherein the shape-retaining jig is composed of two or more wires. 6. The metal carrier according to claim 2, wherein the pin is formed of a solid body or a hollow body. 7. The metal carrier according to claim 3, wherein the wire has a circular cross section or a flat cross section.