JP2009297674A - Metal carrier for exhaust gas purifying catalyst - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a metal carrier for exhaust gas purifying catalyst having a honeycomb body which has a sufficient strength and has also little electric resistance. <P>SOLUTION: The metal carrier housing a metallic honeycomb body H supporting the exhaust gas purifying catalyst in a metallic outer cylinder 1 constitutes the honeycomb body H by arranging many metallic cylindrical tubes 2 mutually closely in the cylinder axial direction in the outer cylinder 1. The many cylindrical tubes 2 are arranged by gathering and bundling to an area Z1 of a regular hexagon having contact with the inner periphery inside the cylindrical outer cylinder 1. Partitions 3 are arranged along each side of the regular hexagon of the area Z1, and cylindrical tubes 41, 42 having respectively contact with the partition 3 and the outer cylinder 1 in the internal and external directions are arranged on a circular area Z2 formed between the partitions 3 and the outer cylinder 1. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a metal carrier for an exhaust gas purification catalyst, and more particularly to a novel structure of the honeycomb structure.

Conventionally, as shown in Patent Document 1, a metal carrier for an exhaust gas purifying catalyst is configured by winding a flat plate and a corrugated plate in a state of overlapping each other to form a honeycomb body, and press-fitting the honeycomb body into a cylindrical outer cylinder. Then, the flat plate and the corrugated plate are joined by diffusion bonding, brazing, or the like. A catalyst is supported on the surface of each cell constituting the honeycomb body.
JP2008-104990

  By the way, when joining a flat plate and a corrugated plate by diffusion bonding, it is necessary that the two are pressed with sufficient contact pressure. Guaranteed by. However, since it is difficult to maintain a sufficiently high contact pressure between the flat plate and the corrugated plate, the bonding strength may be insufficient and the plate may be damaged. In Patent Document 1, in order to solve this problem, the honeycomb body is divided into an inner honeycomb body and an outer honeycomb body, and a rear tensile force and a reduced diameter force are applied to each of them.

  In addition, the cross-sectional shape of each cell of a honeycomb body formed by joining a flat plate and a corrugated plate is usually a triangle or a trapezoid. Therefore, if the cross-sectional area through which the exhaust gas flows is constant, the perimeter is compared to a circle. As a result, there is a problem that the ventilation resistance is large.

  In view of the above, an object of the present invention is to provide a metal carrier for an exhaust gas purifying catalyst having a honeycomb body with sufficient strength and low ventilation resistance.

  In order to achieve the above object, in the metal carrier of the catalytic converter of the first aspect of the invention, in the metal carrier in which the metal honeycomb body (H) carrying the exhaust gas purification catalyst is housed in the metal outer cylinder (1), In the outer cylinder (1), a large number of metal cylindrical tubes (2) are arranged in close contact with each other in the cylinder axis direction to constitute a honeycomb body (H).

  In the metal carrier according to the first aspect of the present invention, the honeycomb body is formed by arranging a large number of metal cylindrical tubes in close contact with each other, so that the conventional metal carrier in which the honeycomb body is constituted by flat plates and corrugated plates. Demonstrates sufficient strength compared to. In addition, since the cross-sectional shape of each cell of the honeycomb body is circular, if the cross-sectional area through which the exhaust gas flows is constant, the peripheral length is the shortest and the ventilation resistance is sufficiently small.

  In the second aspect of the invention, the large number of cylindrical tubes (2) are arranged so as to converge in a regular hexagonal region (Z1) in contact with the inner periphery of the cylindrical outer cylinder (1). In the arc region (Z2) formed between the region (Z1) and the outer tube (1), the cylindrical tube (2) and the outer tube (1) disposed in the regular hexagonal region (Z1) are moved inward and outward. The other cylindrical tubes (43) that are in close contact with each other are disposed. In the second aspect of the present invention, a large number of cylindrical tubes can be accommodated in the cylindrical outer cylinder and can be converged and arranged.

  In the third invention, the partition plate (3) is disposed along each side of the regular hexagon of the region (Z1), and the arc region formed between the partition plate (3) and the outer cylinder (1). In (Z2), other cylindrical tubes (41, 42) are disposed in close contact with the partition plate (3) and the outer cylinder (1) in the inner and outer directions, respectively. In the third aspect of the present invention, a large number of cylindrical tubes can be restricted and converged to a regular hexagonal region by a partition plate, particularly in a relatively large diameter outer cylinder.

  In the method for manufacturing a metal carrier for an exhaust gas purifying catalyst according to the fourth aspect of the invention, a large number of cylindrical tubes (2) are inserted into regular hexagonal openings (521) formed in the jig (5), and these cylindrical tubes (2 ) Is converged to the regular hexagonal region (Z1), and the converged cylindrical tube (2) is inserted into the outer cylinder (1), and then another cylindrical tube (41, 42, 43) is further connected to the outer cylinder (1). ), And the outer cylinder (1) is contracted to hold the cylindrical tube (2) and the other cylindrical tubes (41, 42, 43) in the outer cylinder (1).

  In addition, the code | symbol in the said parenthesis shows the correspondence with the specific means as described in embodiment mentioned later.

  As described above, the exhaust gas purifying catalyst metal carrier of the present invention includes a honeycomb body having sufficient strength and low ventilation resistance.

(First embodiment)
FIG. 1 shows a front view of a metal carrier for an exhaust gas purification catalyst of the present invention, and FIG. 2 shows a longitudinal sectional view thereof. In each figure, the metal carrier includes a metal outer cylinder 1. In the present embodiment, the outer cylinder 1 is a cylindrical body. As an example, the outer cylinder 1 is made of SUS304 stainless steel, has an outer diameter of 65 mm (nominal diameter), a wall thickness of 1.0 mm, and a length of 86 mm.

  A large number of metal cylindrical tubes 2 are arranged in the outer cylinder 1 to constitute a honeycomb body H. These cylindrical tubes 2 are slightly shorter than the cylinder length of the outer cylinder 1, and are positioned inward with a welding allowance of a fixed dimension L (for example, 5 mm) from both end openings 11 and 12 of the outer cylinder 1. It is arranged in the axial direction. The cylindrical tube 2 uses a seamless tube or a semi-seamless tube and is made of, for example, ferritic stainless steel. It is preferable to use a semi-seamless tube in terms of cost and the ability to obtain a thin tube. The outer diameter of the cylindrical tube 2 is a value that is divisible by an integer with respect to the inner diameter of the outer cylinder 1 and is determined in consideration of the required number of cells of the honeycomb H (for example, generally 100 cells / square inch). As an example of the cylindrical tube 2, the outer diameter is 3 mm and the wall thickness is 0.1 mm.

  When a large number of cylindrical tubes 2 are convergingly arranged in the cylindrical axis direction in the circular outer cylinder 1, it is most natural to arrange them in a regular hexagonal region Z1 in contact with the inner periphery of the outer cylinder 1. Therefore, in this embodiment, as shown in FIG. 1, a flat partition plate 3 is provided in the outer cylinder 1. These partition plates 3 have a width slightly smaller than each side of the regular hexagon in contact with the inner circumference of the outer cylinder 1, and a length equal to the length of the cylindrical tube 2, and are regular hexagonal regions surrounded by these partition plates 3. The cylindrical tubes 2 are arranged in close contact with each other in Z1. An example of the partition plate 3 has a plate width of 26 mm and a plate thickness of 0.8 mm. Note that there is no partition plate 3 on the diagonal line of the regular hexagonal region Z1, and all of them are filled with the cylindrical tube 2. This is because if the adjacent partition plates 3 are in contact with each other, the contraction tube described later of the outer cylinder 1 cannot be performed smoothly. Therefore, when the above values are adopted as an example of the dimensions of the outer cylinder 1 and the cylindrical tube 2, 21 cylindrical tubes 2 are arranged on the diagonal line of the regular hexagonal region Z1 as shown in FIG.

  In the six arc regions Z2 formed between each partition plate 3 and the outer cylinder 1, three other cylindrical tubes 41 having the same diameter as the cylindrical tube 2 are provided at the left and right ends, respectively. For example, two other cylindrical tubes 42 each having an outer diameter of 2.2 mm and a wall thickness of 0.1 mm are arranged in close contact with each other, and these other cylindrical tubes 41, 42 are attached to the partition plate 3 and the outer cylinder 1. Touch inward and outward. In addition, by setting the outer diameter tolerance appropriately, four tubes having the same diameter as the cylindrical tube 2 may be arranged as the other cylindrical tubes. According to this, it is necessary to prepare cylindrical tubes having different diameters. Because there is no cost, the cost can be reduced. In any case, the outer diameter and the number of the other cylindrical tubes can be variously changed in design.

  An example of the manufacturing process of the metal carrier having the above structure will be described below. When assembling the metal carrier, for example, a jig 5 as shown in FIG. 3 is used. In FIG. 3, the jig 5 includes support pillars 51 at four corners, and three support plates 52 are supported by the corner parts at intervals in the longitudinal direction. Each holding plate 52 is formed with a regular hexagonal opening 521 having the same shape as the region Z1 on the plate surface. Such a jig 5 is placed on its side as shown in FIG. 4, and in this state, the cylindrical tube 2 is inserted into the opening 521 of the holding plate 52 and laminated. When the inside of the opening 521 is filled with the cylindrical tube 2, the jig 5 is raised (FIG. 5), the holding plate at the uppermost position of the jig is removed (FIG. 6), and the cylindrical tube 2 is focused and exposed to a regular hexagon. A cylindrical outer cylinder 1 having an outer diameter of 65 mm is put on (FIG. 7), and a partition plate 3 is inserted into the outer cylinder 1 so as to surround the converged cylindrical tube 2 (FIG. 8). 7 and 8 are front views in which the outer cylinder 1 is covered from the direction of arrow A in FIG. 6 and the inside is viewed from the opening 11 of the outer cylinder 1.

  Subsequently, cylindrical tubes 41 and 42 are inserted between the partition plate 3 and the outer cylinder 1 (FIG. 9), and the internal cylindrical tube 2 is pressed through the partition plate. The cylindrical tube 2 integrated with the outer cylinder 1 in this way is extracted from the jig 5 together with the outer cylinder 1 (FIG. 10), and then projected from the opening 12 of the outer cylinder 1 using an appropriate pushing tool. The cylindrical tube 2 is pushed into a predetermined position in the outer cylinder 1 (FIG. 11). Then, to prevent the cylindrical tube 2 from coming off, deformable circular pressing plates 51 and 52 such as glass wool having the same diameter as the inner diameters of the openings 11 and 12 of the outer cylinder 1 are inserted from these openings 11 and 12 (FIG. 12). In this state, the outer cylinder 1 is contracted by a known method.

  The cylindrical tubes 2, 41, 42 in the outer cylinder 1 and the partition plate 3, and the cylindrical tube 2, 41, 42, the partition plate 3, and the outer tube 1 are diffused and bonded to each other in a favorable manner by shrinkage processing. It is necessary to press the outer cylinders 1 at a certain pressure or more. Therefore, the relationship between the drawing ratio at the time of the tube reduction and the maximum load after diffusion-bonding the tube reduced at the drawing ratio was examined. This is shown in FIG. The maximum load in FIG. 13 was measured by cutting the metal carrier into a 20 mm width and pushing the honeycomb body H with its φ20 shaft using an Amsler tester. As is clear from FIG. 13, when the drawing ratio is less than 0.8%, the maximum load is reduced from 24 KN, indicating that the pressure contact force is insufficient. On the other hand, if the squeezing rate is larger than 1.5%, the cylindrical tubes 2, 41, and 42 start to be crushed, so that the pressure contact force is insufficient, and the maximum load is still smaller than 24KN. Therefore, in order to bring the cylindrical tubes 2 into pressure contact with each other with sufficient pressure, the squeeze rate should be in the range of 0.8 to 1.5%. Among them, the maximum load is about 1.2% indicating 25KN. It is. When 1.2% contraction is performed, the outer diameter of the outer cylinder 1 is about 64.2 mm (nominal diameter 65 mm). After the tube contraction, the cylindrical tubes 2, 41, 42, the partition plate 3, and the outer cylinder 1 are joined to each other by diffusion bonding. Note that, instead of or in addition to diffusion bonding, bonding may be performed by brazing or the like.

  The metal carrier of the present invention thus produced has sufficient strength as compared with the conventional one. This strength measurement is the same as the measurement of the maximum load described above. The metal carrier is cut into a 20 mm ring, the honeycomb body H is pushed with a shaft of φ20 by an Amsler tester, and the maximum load at this time is measured. According to this, although there is some variation depending on the sample, the maximum load of the metal carrier of the present invention shows a value of about 24 to 25 KN as described above, whereas the honeycomb body is composed of flat plates and corrugated plates. In the conventional metal carrier, the maximum load is 9 KN, which is less than half. This is because the cylindrical tube constituting the metal carrier of the present invention has a closed cross section, so that a sufficient pressing force can be applied when performing diffusion bonding. Thus, it was known that the metal carrier of the present invention has sufficient strength.

  In addition, since the cross-sectional shape of each cell of the honeycomb body is circular in the metal carrier of the present invention, the circumference is the shortest when the cross-sectional area through which the exhaust gas flows is constant, and as a result, the ventilation resistance is sufficiently small. . This is shown in FIG. FIG. 14 shows the relationship between the flow velocity Vm of the rectified compressed air flow passing through the metal carrier and the loss head h2 at this time (the difference in the hydraulic head before and after the metal carrier). 14 line X) and the conventional metal carrier (line Y in FIG. 14), the difference between the loss head (venting resistance) of the two increases as the air flow rate increases. Therefore, the merit of using the metal carrier of the present invention for a high-performance vehicle having a large exhaust gas flow velocity (50 m / s or more) is large.

(Second Embodiment)
As shown in FIG. 15, when the outer cylinder has a relatively small diameter (for example, an outer diameter of 35 mm and a wall thickness of 1.0 mm), the partition plate 3 described in the first embodiment is not necessarily required. The inner and outer directions of the cylindrical tube 2 in the regular hexagonal region Z1 (for example, an outer diameter of 3 mm and a wall thickness of 0.1 mm) are arranged at the left and right positions in the arc region Z2 formed between each side of the regular hexagon and the outer cylinder 1. A cylindrical tube 43 (for example, an outer diameter of 2.2 mm and a wall thickness of 0.1 mm) in contact with the cylindrical tube 2 and the outer cylinder 1 is disposed, and the cylindrical tube 2 is pressed by these cylindrical tubes 43.

  In each of the above embodiments, the cylindrical tube 2 does not necessarily have to converge to the regular hexagonal region Z1.

It is a front view of the metal carrier in a 1st embodiment of the present invention. It is a longitudinal cross-sectional view of a metal carrier. It is a perspective view of a manufacturing jig. It is a perspective view which shows the manufacturing process of a metal carrier. It is a perspective view which shows the manufacturing process of a metal carrier. It is a perspective view which shows the manufacturing process of a metal carrier. It is a perspective view which shows the manufacturing process of a metal carrier. It is a perspective view which shows the manufacturing process of a metal carrier. It is a perspective view which shows the manufacturing process of a metal carrier. It is a perspective view which shows the manufacturing process of a metal carrier. It is a perspective view which shows the manufacturing process of a metal carrier. It is a perspective view which shows the manufacturing process of a metal carrier. It is a graph which shows the relationship between the draw ratio at the time of an outer tube | pipe contraction process, and a maximum load. It is a graph which shows the relationship between the flow velocity of the airflow which passes a metal support | carrier, and a loss head. It is a front view of the metal carrier in 2nd Embodiment of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Outer cylinder, 2 ... Cylindrical tube, 3 ... Partition plate, Z2 ... Arc region, 41, 42, 43 ... Cylindrical tube (other cylindrical tubes), 5 ... Jig, 52 ... Holding plate, 521 ... Opening, H ... honeycomb body, Z1 ... regular hexagonal region, Z2 ... arc region.

Claims (4)

In a metal carrier in which a metal honeycomb body carrying an exhaust gas purification catalyst is housed in a metal outer cylinder, a number of metal cylindrical tubes are disposed in close contact with each other in the cylinder axis direction in the outer cylinder. A metal carrier of a catalytic converter that constitutes a honeycomb body. The plurality of cylindrical tubes are arranged so as to converge in a regular hexagonal region in contact with the inner periphery of the cylindrical outer cylinder, and an arc region formed between the region and the outer cylinder. 2. The metal carrier for an exhaust gas purifying catalyst according to claim 1, wherein other cylindrical tubes that are in close contact with the cylindrical tube and the outer cylinder disposed in the regular hexagonal region in the inner and outer directions are disposed. A partition plate is disposed along each side of the regular hexagon of the region, and an arc region formed between the partition plate and the outer tube is in close contact with the partition plate and the outer tube in the inner and outer directions. The exhaust gas purifying catalyst metal carrier according to claim 2, wherein another cylindrical tube is disposed. After inserting a large number of the cylindrical tubes into regular hexagonal openings formed in the jig to converge the cylindrical tubes into the regular hexagonal region, and inserting the converged cylindrical tubes into the outer cylinder, The exhaust gas purification catalyst according to claim 2 or 3, wherein another cylindrical tube is inserted into the outer cylinder, and the outer cylinder is contracted to hold the cylindrical tube and the other cylindrical tube in the outer cylinder. Method for manufacturing metal carrier.

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