JPH07171415A - Metal carrier - Google Patents

Abstract

PURPOSE:To improve the exhaust gas purifying capacity and durability of a metal carrier for carrying a catalyst to purify the exhaust gas from an automobile by forming each stack with the flat strip and/or corrugated strip each having at least one hole almost at its center. CONSTITUTION:An S-shaped metal honeycomb body H1 is formed by laminating a set of the flat strip and corrugated strip made of thin steel sheet in the desired number of stages to form one stack S1 and winding the plural stacks from the center of the honeycomb body H1 in the same direction into the shape of an S. In this case, a hole A is allowed to pierce the stack S1 vertically almost at the center to provide a space of desired volume almost at the center of the stack S1 in the axial direction of the honeycomb body H1. Consequently, the deforming force due to the large thermal stress generated at the center of the honeycomb body H1 is effectively divided by the presence of the space, and the center is not sprung out.

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. (Referred to as a honeycomb body)) as a main component.

More specifically, the present invention mainly uses, as a metal carrier, an S-shaped or Tomoe-shaped metal honeycomb body for carrying an exhaust gas purifying catalyst, and the metal honeycomb body. It is an object of the present invention to provide a metal carrier having improved durability of the center of the body.

[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. In general,
Metal monolithic metal carrier (MS, metal substrate) for supporting a catalyst for exhaust gas purification
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 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 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, honeycomb bodies of S-shaped type, tongue-shaped type, and X-wrap type are proposed.

The above-mentioned S-shaped 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]

The durability of the outer peripheral portion of various types of metal honeycomb bodies other than the wound type constituting the above-mentioned metal carrier, particularly the S-shaped type and the tongue-shaped type, is excellent. Has been improved as described above, but it is required to improve the durability of the central portion of the metal honeycomb body in relation to it. In improving the durability of the central portion, it is possible to prevent or suppress the phenomenon that the central portion of the metal honeycomb body jumps out (in the axial direction of the metal honeycomb body) (which is said to be telescoping, film out, etc.). This is a big issue. 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 decrease in durability of the central portion of the metal honeycomb body is the deforming force due to the large thermal stress applied to the central portion of the metal honeycomb body. To improve it, the central portion of the metal honeycomb body is improved. It is important to take measures to absorb and mitigate the thermal stress of The inventors of the present invention have made earnest studies on measures for improving the durability of the S-shaped type and the honeycomb type metallic honeycomb bodies, particularly the durability of the central portion.

As a result, a desired number of stacks (S) formed by alternately stacking flat plate-shaped strips and corrugated strips made of heat-resistant thin metal plates in a desired number of stages are used, for example, one When manufacturing an S-shaped metal honeycomb body using the stack (S ₁ ), or a three-sided metal honeycomb body using the three stacks (S _{1 to} S ₃ ), the stack (S ₁ It has been found that when a hole having a hole penetrating in the vertical direction of the stack (S) is used in the substantially central part as), the thermal stress in the central part can be effectively absorbed / relaxed. Was issued.

In addition, in this type of S-shaped or tongue-shaped metal honeycomb body, the processing stress is concentrated in the central portion of the stack due to the manufacturing process. However, it has been found that it is difficult to manufacture a uniform cell, but there is also an effect that a uniform cell can be obtained by using the stack having the above structure. 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 has been found that the advantages of uniformity of outside air gas purification ability and improvement of purification rate can also be obtained. In addition, it was also found that the heat capacity of the honeycomb body is small in the approximately central portion, so that the time until the catalyst is activated at the time of cold start is shortened, that is, the light-off performance is improved.

The present invention has been completed on the basis of the above-mentioned findings, and the main constituent element of the present invention is an S-shaped or bead-shaped metal honeycomb body excellent in exhaust gas purification performance and durability. A metal carrier is provided.

[0013]

The present invention will be described in brief. The present invention is based on at least one stack formed by alternately laminating flat plate-shaped strips and corrugated strips made of thin metal plates in a desired number of stages. (S) is used, a winding jig is disposed on the outer surface of the substantially central portion of each stack, and the stack is wound and molded, and the flat plate-shaped strips and corrugated strip-shaped strips of each stack have end portions. A metal carrier comprising: an X-wrap type metal honeycomb body for supporting an exhaust gas purifying catalyst, which has a structure in contact with an inner wall surface of an outer metal casing, and a metal casing for housing the metal honeycomb body. 2. The metal carrier according to claim 1, wherein each of the stacks (S) is composed of a flat plate-shaped strip material and / or a corrugated plate-shaped strip material having at least one hole in a substantially central portion.

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

As described above, the present invention aims to improve the S-shaped type and the B-shaped type of the metal honeycomb body having various structures which are the main constituent elements of the metal carrier. It has characteristics.

An outline including the manufacturing process of the S-shaped metal honeycomb body is shown in FIGS.
That is, FIG. 7 shows an S-shaped metal honeycomb body (H ₁ ).
7 is a front view of the metal honeycomb body (H ₁ ) shown in FIG.
FIG. 8 shows a stack (S ′ ₁ ) used to manufacture the same, and FIG. 8 shows two winding jigs (W ₁ , W ₂ ) on the upper and lower outer surfaces of the central portion of the stack (S ′ ₁ ). And a winding jig is wound in the same direction to manufacture an S-shaped metal honeycomb body (H ₁ ).
7 to 9, only some flat plate-shaped strips and corrugated strip-shaped strips are shown for clarity, and the others are omitted.

As shown in the figure, the S-shaped metal honeycomb body (H ₁ ) comprises a set of thin strip steel plates (1) and corrugated strips (2) as a minimum structure. It is manufactured as a unit. That is, as shown in FIG. 8, the flat strip (1) and the corrugated strip (2) are alternately laminated at a desired stage to form a stack (S ′ ₁ ). Next, as shown in FIG. 9, two winding molding jigs (W ₁ , W ₂ ) are arranged on the outer surface (upper surface and lower surface) of the stack (S ′ ₁ ) and the jigs are arranged in the same direction. By winding, the S-shaped metal honeycomb body (H ₁ ) shown in FIG. 7 is manufactured. In the figure, (3) indicates a cell. In addition, as shown in FIG. 7, since the stack (S ′ ₁ ) is curved in an S shape at the center of the metal honeycomb body (H ₁ ),
In this industry, this type of metal honeycomb body is commonly called an S-shaped type. Therefore, it should be noted that the S-shaped metal honeycomb body in the present invention is a general term for those manufactured by the manufacturing process.

The outline including the manufacturing process of the above-mentioned toe-shaped type metal honeycomb body is shown in FIGS. Note that FIG. 10 is a front view of the metal honeycomb body (H ₂ ) of a barb type, but only some flat plate-shaped strips and corrugated strips are shown for clarity. And the others are omitted. The toe-shaped metal honeycomb body (H ₂ ) is manufactured as follows, as shown in FIG. 11. That is, the flat strip (1)
Using three stacks (S ₁ ′, S ₂ ′, S ₃ ′) formed by laminating the corrugated plate-shaped strip material (2) in a desired number of steps, the central angle of each stack is 120 °. Abut and combine. Next, a total of three winding molding jigs (W ₁ , W ₂ , W ₃ ), one on the outer surface of the center of each stack
10 is arranged as shown in FIG. 11, and the jig is wound in the same direction (for example, clockwise direction), so that
The Tomoe type metal honeycomb body (H ₂ ) shown in FIG.

As described above, the above-mentioned S-shaped or Tomoe-shaped metal honeycomb body is improved in durability, especially in the outer peripheral portion, as compared with, for example, a wound type metal honeycomb body. is there. However, in contrast to the durability of the outer peripheral portion, conversely, improvement of the durability of the central portion is strongly demanded. Further, in this type of S-shaped metal honeycomb body, as can be seen from the above-described manufacturing example, flat plate-shaped strips and corrugated plate-shaped strips, which are the minimum constitutional units of the stack (S), are alternately contacted. And stacking these at a desired stage to form a stack (S), and then, when the stack (S) is roll-formed into an S-shaped or a toe-shaped structure, particularly when each stack is a processing center. A large processing stress is applied to each minimum structural unit in the central part, causing a large deviation from each other, forming a region where there is no corrugated strip between the flat strips, and there is also a gap. The corrugated shape of the corrugated strip may be deformed in conjunction with. These are major negative factors in manufacturing a metal honeycomb body having a uniform cell shape and cell density. In other words, it goes without saying that they cause a non-uniform distribution of the amount of catalyst carried inside the metal honeycomb body, and a non-uniform purification ability.

The present invention improves the durability of the central portion of an S-shaped or tongue-shaped metal honeycomb body,
In addition, in order to eliminate the drawbacks resulting from the above-mentioned manufacturing process, a flat plate-shaped strip and / or a corrugated plate-shaped strip having at least one or more holes in a portion located at the substantially central portion of the stack (S) is used. The technical configuration of using the stack (S) to configure is adopted. By adopting the above-mentioned technical configuration, the S-shaped or tongue-shaped 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. Further, since the band material has the hole portion at the processing center, the stack is smoothly wound and formed, so that the waveform deformation due to the processing stress is prevented, and the metal honeycomb body having uniform cells can be manufactured.
Hereinafter, specific embodiments of the technical configuration of the present invention will be described.

FIG. 1 shows the holes (A) of the first embodiment used for producing an S-shaped metal honeycomb body.
Is a perspective view seen through a part of the stack (S ₁₎ with. Incidentally, FIG. 1 corresponds to FIG. 8 showing the above-mentioned conventional stack (S ₁ ′). The stack of the present invention (S
₁ ) is largely different from the conventional _{one in} that it has a hole (A) penetrating in the vertical direction in the approximate center of the stack.
To construct the stack (S 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. To form a stack (S ₁ ).
Needless to say, the holes (a) of both strips (1, 2) form the holes (A) of the stack (S ₁ ).
3 is an S-shaped metal honeycomb body manufactured by winding the stack (S ₁ ) shown in FIG. 1 according to a conventional method (see the manufacturing process shown in FIGS. 7 to 9 described above). 2 is a cross-sectional view taken along the line I-I of FIG. 1. It is shown 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 (H ₁ ).

In the present invention, the flat plate-shaped strip (1) used for producing the S-shaped 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% -A
Heat resistant stainless steel such as 15%, 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, corrugated strip (2)
Is a predetermined substantially sine wave from the flat strip (1),
The one additionally processed to have a substantially triangular wave or a substantially trapezoidal wave is used. It should be noted that 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 above-mentioned 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 S-shaped metal honeycomb body is used by being inserted and fixed in a metal casing (C) as shown in FIGS. 7 and 10. As the material of the metal casing (C) described above, heat resistant steel of the same kind as the strip materials (1, 2) forming the metal honeycomb body may be used, or a material having high heat and corrosion resistance may be used. . In addition, a double structure in which the metal material of the outer part is richer in heat resistance and corrosion resistance than the inner part,
Specifically, it is also possible to use one in which ferritic stainless steel is used for the inner part and austenitic stainless steel is used for the outer part.

FIG. 4 is a sectional view of a stack (S ₁ ) having holes (A) of the second embodiment used for manufacturing the metal honeycomb body of the present invention. FIG. 4 shows I of FIG.
It is sectional drawing of the -I line direction. The second embodiment is different from the first embodiment shown in FIG. 1 in the shape of the hole (A). As a result, the shape of the space space portion (SP) formed at the central portion in the axial direction of the metal honeycomb body also becomes different.

FIG. 5 is a plan view of the stack (S ₁ ) having holes (A) of the third embodiment used for manufacturing the metal honeycomb body of the present invention. In the third embodiment, compared to the first embodiment, the hole (A) has an oblong (race track) type instead of a rectangular plan shape. In such a case, stress concentration on the corners of the hole (A) can be avoided, so that the durability can be further improved.

FIG. 6 is a sectional view of a stack (S ₁ ) having holes (A) of a 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 (S ₂ ) is arranged in the hole (A). As the other stack (S ₂ ), one having a small cell density is arranged as shown in the figure. Considering that the flow velocity distribution of the exhaust gas flow is faster in the central portion of the metal honeycomb body than in the other portions, the stack (S ₁ + S
By using ₂ ), the amount of catalyst supported in the central portion can be increased, so that the exhaust gas purification ability can be made the same as that of other portions.

Although not shown, the stack (S) used for manufacturing the metal honeycomb body of the present invention is limited to one having a hole (A) penetrating in the vertical direction as shown in the above embodiment. Not done. 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 (S). It is needless to say that the above may be configured.

[0028]

In the metal carrier of the present invention, the main component of the metal honeycomb body of S-shaped type or Tomoe-shaped type is that the flat band material and the corrugated plate material are alternately laminated in the desired number of steps. Using a desired number of stacks (S) formed by the above, a winding jig is arranged on the outer surface of the substantially central portion of each stack, and each stack (S) is wound by the jig. Although formed by molding, a flat strip and / or a corrugated strip having a desired number, a desired size, and a desired shape of holes in substantially the center of each stack (S). It is characterized in that it is made of material. Therefore, since the S-shaped or tongue-shaped metal honeycomb body of the present invention uses the stack (S) having the above-mentioned structure, it has a space of a desired volume in the axial central portion of the metal honeycomb body. is there.

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 stirred and mixed in the space, the exhaust gas purification rate can be increased. Furthermore, when manufacturing an S-shaped metal honeycomb body from the stack (S) by winding molding, the strip material (flat plate strip material and / or corrugated strip material) is
The metal honeycomb with a uniform cell shape and uniform cell density has little deformation of the waveform of the corrugated strip material because it has a hole in the approximate center where large processing stress is applied, so it can be smoothly rolled and formed. The body can be provided.

[Brief description of drawings]

FIG. 1 is a perspective view of a part of a stack (S ₁ ) of a first embodiment seen through.

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

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

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

FIG. 5 is a plan view of a stack (S ₁ ) according to a third embodiment.

FIG. 6 is a sectional view of a stack (S ₁ ) according to a fourth embodiment.

FIG. 7 is a front view in which a part of the S-shaped metal honeycomb body is omitted.

FIG. 8 is a perspective view of a stack (S ′ ₁ ) used for manufacturing a conventional S-shaped metal honeycomb body.

FIG. 9 is a diagram illustrating a method of manufacturing an S-shaped metal honeycomb body (rolling molding method).

FIG. 10 is a front view in which a part of a B-shaped metal honeycomb body is omitted.

[Fig. 11] Fig. 11 is a diagram for explaining a manufacturing method (winding molding method) of a bead-shaped metal honeycomb body.

[Explanation of symbols]

MS ......... metal carrier H _1, H ₂ ......... metallic honeycomb body 1 ......... flat strip 2 ......... wave plate strip 3 ......... cell (reticulated vent path) _{S'1, S'2, S'3} ......... conventional stacked _{W 1, W 2, W 3} ......... winding molding jig

Claims (7)

[Claims] 1. Use of at least one stack (S) formed by alternately laminating flat band-shaped strips and corrugated strips made of thin metal plates in a desired number of stages, and using the stacks at the substantially central portion of each stack. Exhaust gas with a structure in which a winding jig is placed on the outer surface and winding molding is performed, and the ends of the flat strips and corrugated strips of each stack are in contact with the inner wall surface of the metal casing A metal honeycomb body for carrying a purification catalyst, and a metal casing for housing the metal honeycomb body,
In the metal carrier consisting of, each of the stacks (S) is composed of a flat plate-shaped band member and / or a corrugated plate-shaped band member having at least one hole in a substantially central portion thereof. . 2. The metal carrier according to claim 1, wherein each of the stacks has a hole that is formed at a substantially central portion of the stack and penetrates the stack in the vertical direction. 3. The metal carrier according to claim 2, wherein the through hole has a desired shape. 4. The metal carrier according to claim 2, wherein each stack has a hole portion at a substantially central portion thereof, and the hole portion accommodates another stack. 5. The metal carrier according to claim 1, wherein only the flat plate-shaped strip material forming each stack has a hole in a substantially central portion. 6. The metal carrier according to claim 1, wherein only the corrugated plate-shaped strip material forming each stack has a hole portion at a substantially central portion. 7. The metal carrier according to claim 1, wherein the metal honeycomb body is of an S-shaped type or a B-shaped type.