JPH08266905A - Metal carrier - Google Patents

Abstract

PURPOSE: To provide a metal carrier having high freedom by a simple method by providing an intermediate body between an outer cylinder and a honeycomb body in a structure in which the honeycomb body of the metal carrier is bonded entirely or the temperature variation of exhaust gas is large and high durability is not obtained. CONSTITUTION: As a metal carrier of good durability, plane foils and corrugated foils are wound or laminated alternately to form a honeycomb body 4, and then a sheet of same thickness as that of foils or thicker is wound on the outside of the body twice or more to form an intermediate body 5. The inner face of the intermediate body 5 and the outer face of the honeycomb body 1 are continuously or intermittently bonded one round, and the outer face of the intermediate body 5 is bonded with an outer cylinder 6 within one round, and also an unbonded layer of one round or more is formed in the intermediate body 5.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a metal carrier for purifying exhaust gas discharged from an internal combustion engine such as an automobile engine.

[0002]

2. Description of the Related Art Conventionally, a ceramic metal carrier has been used for a catalytic converter for purifying exhaust gas, but recently, the use of the metal carrier has been increasing in view of heat resistance, low pressure loss and mountability.

The metal carrier is formed by spirally winding a flat foil made of a metal such as ferritic stainless steel having a heat resistance of about 50 μm and a corrugated corrugated corrugated foil into a honeycomb body. This is housed in an outer cylinder made of a corrosion-resistant and heat-resistant metal such as ferritic stainless steel, which also has heat resistance, and is joined to each other by brazing or the like.

This metal carrier is loaded with a catalyst for purifying exhaust gas such as platinum, palladium and rhodium, and then mounted and used in an exhaust gas system of an automobile engine, for example. for that reason,
This metal carrier has severe temperature changes due to changes in operating conditions,
It suffers from vibration, but if damaged, not only the purification performance will deteriorate, but also exhaust system closure or engine damage will be required, so particularly high durability is required.

The thermal stress acting on the metal carrier is particularly large between the outer cylinder and the honeycomb body having a large temperature difference, and various bonding structures have conventionally been proposed in order to reduce the stress. For example, as disclosed in Japanese Patent Application Laid-Open No. 4-148016, the joint structure inside the honeycomb body and the joint portion between the honeycomb body and the outer cylinder are specified to increase the degree of freedom with respect to thermal deformation so that a so-called flexible structure can be obtained, and thermal stress The lowering method, or JP-A-3-157139 and JP-A-2-298.
As disclosed in Japanese Patent Laid-Open No. 620, a tubular intermediate body is arranged between a honeycomb body and an outer cylinder, and is joined to the honeycomb body on the inner side and the outer cylinder on the outer side. There is also a method of increasing the degree of freedom with respect to thermal deformation by not allowing it.

In the conventional method, the degree of freedom with respect to thermal deformation is improved and good durability is ensured by rationalizing the joining structure between the inside of the honeycomb body and the outer cylinder and the honeycomb body and providing an intermediate body. However, there is a problem that manufacturing is complicated, productivity is low, and cost is high. When the honeycomb body is diffusion-bonded, all contact points between the flat foil and the corrugated foil are bonded unless special measures are taken, but when the honeycomb body is entirely bonded in this way, the outer cylinder and the honeycomb body are bonded together. Although it is necessary to further increase the degree of freedom with respect to deformation, there is a problem in that the conventional method is insufficient, and the honeycomb body supporting portion is damaged and is displaced at the end.

[0007]

DISCLOSURE OF THE INVENTION According to the present invention, the honeycomb bodies of the metal carrier are wholly joined or the temperature of the exhaust gas changes greatly, and the conventional method lacks the degree of freedom for deformation between the honeycomb body and the outer cylinder. Therefore, when high durability cannot be obtained, a metal carrier is provided in which a high degree of freedom is provided by a simple method by providing an intermediate between the outer cylinder and the honeycomb body.

[0008]

Means for Solving the Problems That is, the present invention provides, as a durable metal carrier, (1) after forming a honeycomb body in which flat foil and corrugated foil are alternately wound or laminated, and then a foil is formed on the outside thereof. The same or thicker thin plate is wound two or more times to form an intermediate body, and the inner surface of the intermediate body and the honeycomb-to-outer surface continuously or intermittently make one round, and the outer surface of the intermediate body forms an outer cylinder. A metal carrier characterized by being joined within one round and further provided with a non-joining layer of one round or more inside the intermediate body, (2) The inside of the honeycomb body being wholly joined, A metal carrier, (3) the metal carrier according to the above (1) or (2), characterized in that the intermediate body is a flat plate that is not corrugated.
(4) The metal carrier according to any one of (1) to (3) above, wherein the intermediate body is a corrugated corrugated plate, and (5) the intermediate body and the honeycomb body are on the upstream side, and are intermediate. The body and the outer cylinder are joined on the downstream side, which is the metal carrier as described in any of the above (1) to (4).

Hereinafter, the present invention will be described in detail. FIG. 1 is an external view of a metal carrier 1 of the present invention. Outside the honeycomb body 4 formed by winding or laminating the flat foil 2 and the corrugated foil 3,
The intermediate body 5 wound twice or more is further provided with an outer cylinder 6 on the outer side thereof.
Is arranged. In the same structure, the honeycomb body 4 is joined to the inner surface of the intermediate body 5, and the outer surface of the intermediate body 5 is joined to the inner surface of the outer cylinder 6. However, the inside of the intermediate body 5 wound in multiple layers is not joined.

The plate thickness of the intermediate body 5 is thinner than that of the outer cylinder 6,
It is set thicker than the flat foil 2 and the corrugated foil 3 which form the honeycomb body. The intermediate body 5 is joined to the honeycomb body 4 continuously or intermittently for one round, and is joined to the outer cylinder 6 within one round continuously or intermittently.

Therefore, the intermediate 5 of the metal carrier 1 of the present invention
In terms of thermal stress, has a role like a coil spring that holds the honeycomb body 4 on the inner circumference and is connected to the outer cylinder 6 on the outer surface, and can easily follow radial displacement. In terms of heat conduction, the non-bonding layer inside the intermediate body 5 acts as a heat insulating layer, and the temperature difference between the honeycomb body 4 and the intermediate body 5 becomes small, and at the same time, the temperature difference between the intermediate body 5 and the outer cylinder 6 also becomes small. The stress generated between the honeycomb body 4 and the outer cylinder 6 can be reduced.

Since the catalyst is applied to the honeycomb body 4, reaction heat of the catalyst is generated and thermal stress is generated in the axial direction.
However, since the entire honeycomb body 4 is bonded, the displacement in the axial direction is forcibly restrained, so that the displacement amount becomes small and good durability can be secured.

FIG. 2 is a diagram showing the structure of the metal carrier 1 of the present invention. The appearance of the honeycomb body 4 formed by winding the flat foil 2 and the corrugated foil 3 is shown in (a), and the appearance of the intermediate body 5 that wraps the honeycomb body 4 is shown in (b). It has been curled more than once. Although the intermediate body is shown as a flat thin plate in FIG. 2, a corrugated corrugated foil is similarly used.
You may curl more than once. (C) shows the outer appearance of the outer cylinder 6 that houses the honeycomb body 4 and the intermediate cylinder 5. For these contact surfaces, for example, when brazing, a brazing material for joining to each other, or in the case of diffusion joining, preparation is made so that the interface joining can be cleaned and joined. After being coated, etc., they are assembled so that the necessary pressing force is applied and they are in close contact.

Various bonding structures in the metal carrier of the present invention will be shown below. 3 to 6 show an embodiment of the joint structure in the vertical cross section of the metal carrier, and FIGS. 7 to 10 show the joint structure in the horizontal cross section of each metal carrier. There is no specific combination of the joining structure of the vertical cross section and the joining structure of the cross section, and they can be appropriately combined and used.

In FIG. 3, in the honeycomb body 4, all the contact points of the flat foil and the corrugated foil are bonded in principle by, for example, diffusion bonding or brazing in a shaded area. Reference numeral 5 denotes an intermediate body, and a portion 7 (a portion within a range indicated by a dot) on the inner surface of the intermediate body, which is in contact with the outer surface of the honeycomb body 4, is joined in the entire length in the axial direction. Similarly, a portion 8 (a portion within a range indicated by a dot) in contact with the outer surface of the intermediate body 5 and the inner surface of the outer cylinder 6 is joined to the entire length in the axial direction. However, the intermediate layer 9 other than the inner and outer surfaces of the intermediate body 5 is not joined.

FIG. 4 is adopted when the degree of freedom of the intermediate body 5 is utilized to the maximum. Similarly, in the honeycomb body 4, the range indicated by diagonal lines is, for example, by diffusion bonding or brazing, so that all of the flat foil and the corrugated foil can be obtained. The contacts are in principle joined. Intermediate 5
The portion 7 of the inner surface of the honeycomb body 4 that contacts the outer surface of the honeycomb body 4 is joined in the axial direction, for example, in a specific range on the exhaust gas inlet side,
The portion 8 in contact with the inner surface of is joined in the axial direction, for example, in a specific range on the exhaust gas outlet side. However, the intermediate layer 9 is not joined except for the parts other than the parts 7 and 8 which are not shown and the inner and outer surfaces of the intermediate body 5.

FIG. 5 is used when, for example, the joint portion of the intermediate body 5 with the honeycomb body 4 and the outer cylinder 6 is protected from high-temperature exhaust gas. Alternatively, by brazing, all the contacts of the flat foil and the corrugated foil are basically joined. A portion 7 of the inner surface of the intermediate body 5 which is in contact with the outer surface of the honeycomb body 4 is joined in the axial direction, for example, a specific range on the exhaust gas outlet side, and a portion 8 of which is in contact with the inner surface of the outer cylinder 6 is in the axial direction, for example the exhaust gas. The specified area on the output side is joined. However, the intermediate layer 9 other than the inner and outer surfaces of the intermediate body 5 is not joined. Although the length of the intermediate body 5 is limited to the joining range in FIG. 5, there is no problem if it is longer than the joining length.

FIG. 6 is used to prevent the honeycomb body 5 from tilting in the outer cylinder 6 during use because the honeycomb body 5 has a short length, for example. In the figure, the honeycomb body 4 has a short length, but the intermediate body 5 and the outer cylinder 6 are longer than the honeycomb body 4 and have such a length that the posture thereof can be maintained even if deformation occurs during use. . In the honeycomb body 4, all the contact points of the flat foil and the corrugated foil are bonded in principle by, for example, diffusion bonding or brazing in the shaded area as in the above. The portion 7 of the inner surface of the intermediate body 5 which is in contact with the outer surface of the honeycomb body 4 is in the axial direction,
For example, the portion 8 that is joined over the entire length and is in contact with the inner surface of the outer cylinder 6 is joined over the entire length in the axial direction. However, similarly, the intermediate layer 9 other than the inner and outer surfaces of the intermediate body 5 is not joined.

In FIG. 7, in the honeycomb body 4, all the contact points of the flat foil and the corrugated foil in the shaded area are joined, and the inner surface of the intermediate body 5 is joined along the entire circumference (the portion in the area indicated by the dots). Further, the outer surface of the intermediate body 5 is joined to the outer cylinder 6 along the entire circumference (a portion within a range indicated by a dot). However, the intermediate layer 9 of the intermediate 5
Are not joined.

In FIG. 8, the intermediate body 5 and the outer cylinder 6 are thicker than the foil of the honeycomb body 4 and are a joining structure adopted when it is not necessary to join them all around. The joining of the inside of the honeycomb body 4 and the joining of the honeycomb body 4 and the intermediate body 5 are the same as in the case of FIG. 7, but the outer surface of the intermediate body 5 and the inner surface of the outer cylinder 6 are not the entire circumference, only a part of them is Areas not shown by the points are not joined. In this case, if the non-bonded portion of the intermediate body 5 is not required to make one round or more, the curling range of the intermediate body 5 may be set to two or less as an application of the present invention, and the intermediate body 5 can be saved.

FIG. 9 shows a structure adopted to save the bonding material between the intermediate body 5 and the outer cylinder 6. That is, the parts in the range shown by the points between the intermediate body 5 and the outer cylinder 6 are joined, and the parts not joined in the ranges not shown by the points are alternately arranged. As in the above, the layers inside the intermediate body 5 are not joined.

FIG. 10 further shows a honeycomb body 4 and an intermediate body 5.
This structure is used when saving the space between the intermediate body 5 and the outer cylinder 6. In the figure, parts in the range shown by dots are joined, and parts in the range not shown are not joined. That is, the honeycomb body 4 is entirely joined, the honeycomb body 4 and the intermediate body 5 are joined intermittently, and the intermediate body 5 and the outer cylinder 6 are joined at a part thereof.

As the above-mentioned application, it is possible to further improve the durability by adopting a known honeycomb body having a non-bonded portion at a specific location inside thereof in the metal carrier of the present invention.
However, in terms of manufacturing cost, it is advantageous to adopt a honeycomb body that is wholly bonded as in the present invention.

The metal carrier 1 of the present invention is used in the same manner as a conventionally known metal carrier after being loaded with a noble metal such as platinum, palladium or rhodium for purifying exhaust gas, and then attached to an exhaust system of an automobile, for example. It Since the metal carrier undergoes a drastic temperature change at the same location, a large temperature difference occurs in the radial direction, and the outer cylinder 6 exerts a strong compressive tensile force on the honeycomb body 4.

The honeycomb body 4 is pressed against the outer cylinder 6 through the intermediate body 5 by thermal expansion, but the first thermal expansion causes the outer layer of the honeycomb body 4 to be slightly crushed to reduce the outer diameter. The thermal expansion causes almost no compressive stress. On the other hand, the tensile force due to thermal contraction is generated by repeating thermal expansion and thermal contraction in each thermal cycle. However, since the intermediate body 5 in which the inner layers are not joined is arranged, the deformation is absorbed and the stress generated in the honeycomb body 4 is significantly reduced. Furthermore, since the non-bonding layer of the intermediate body 5 is thermally insulated from the outer cylinder, the temperature distribution generated in the honeycomb body is improved and the durability is improved. Next, examples of the present invention will be described.

[0026]

EXAMPLE FIG. 3 shows a metal carrier A according to an example of the present invention. The junction structure of the cross section is shown in FIG. Outer cylinder 6 is 19Cr
A ferritic stainless steel containing -0.4 Nb as an alloy component, with an outer diameter of 100 mm, a length of 110 mm, and a thickness of 1.5.
mm. The honeycomb body 4 is a ferritic stainless steel having an alloy component of 20Cr-5A and an outer diameter of 96.4.
It is composed of a flat foil 4 and a corrugated foil 5 having a thickness of 50 μm. The cell density of the honeycomb body 4 is 400 cells / square inch. Intermediate 5 is a phyllite stainless steel containing 20Cr-5Al as an alloy component, and its length is 100 mm.
It is curled once and has an outer diameter of 97 mm and a thickness of 150 μm.

The inside of the honeycomb body 4 is joined by brazing or diffusion joining. The joining of the honeycomb body 4 and the intermediate body 5 and the joining of the intermediate body 5 and the outer cylinder 6 are made of Ni brazing material containing Ni as a main component. It is joined.

FIG. 4 shows a metal carrier B according to another embodiment of the present invention.
Indicates. The junction structure of the cross section is shown in FIG. Outer cylinder 6,
The material, dimensions and joining method of the honeycomb body 4 and the intermediate body 5 are the same as those of the metal carrier A. The honeycomb body 4 and the intermediate body 5 are joined with a brazing filler metal within a range of 50 mm from the carrier entrance side end face, and the intermediate body 5 and the outer cylinder 6 are joined with a brazing filler metal within a range of 50 mm from the carrier center to the exit side end face.

FIG. 5 shows a metal carrier C according to another embodiment of the present invention.
Indicates. The junction structure of the cross section is shown in FIG. Outer cylinder 6,
The intermediate body 5 and the honeycomb body 4 are the same except that the length is 50 mm.
The material, dimensions, and joining method of are the same as those of the metal carrier A. The intermediate body 5 is arranged on the exit side from the center of the metal carrier,
The honeycomb body 4 and the intermediate body 5 are brazed in the entire length in the axial direction, and the intermediate body 5 and the outer cylinder 6 are brazed in the entire length in the axial direction.

FIG. 6 shows a metal carrier D according to another embodiment of the present invention.
Indicates. The junction structure of the cross section is shown in FIG. Outer cylinder 6,
The material, dimensions, and joining method of the intermediate body 5 and the honeycomb body 4 are the same as those of the metal carrier A, except that the length is 50 mm. The honeycomb body 4 is arranged on the inlet side of the carrier, the honeycomb body 4 and the intermediate body 5 are brazed in the entire length in the axial direction, and the intermediate body 5 and the outer cylinder 6 are brazed in the entire length in the axial direction.

FIG. 11 shows a known metal carrier E for comparison with the metal carrier of the present invention. The dimensions and material of each part of the metal carrier are the same, but the outer diameter of the honeycomb body 4 is 97 mm because there is no intermediate body. The inside of the honeycomb body 10 is joined by brazing in the shaded area. Honeycomb body 1
0 and the outer cylinder 6 are brazed at a portion 11 in the range indicated by a point near the exit side of the metal carrier, and are free from thermal expansion and contraction in the radial direction and the axial direction due to exhaust gas having a large temperature change. Since it can be transformed into a honeycomb body 10 and an outer cylinder 6
A large thermal stress is hardly generated between the two, and high durability is secured. However, in order to pattern the bonding inside the honeycomb body 10 as shown in the figure, a complicated manufacturing process is required, and there is a problem that the manufacturing cost is increased.

FIG. 12 shows a known metal carrier F for comparison with the metal carrier of the present invention. The outer cylinder 6, the honeycomb body 4, and the intermediate body 12 are made of the same material. The outer cylinder 6 has the same size as the metal carrier A, but the intermediate body 12 has a thickness of 15
Although it is 0 μm, it only makes one round around the honeycomb body 4. Similarly, the inside of the honeycomb body 4 is entirely joined by diffusion joining or brazing in the shaded area.
In FIG. 3, the intermediate body 11 and the outer cylinder 6 are joined at the outlet-side vicinity portion 14. The structure is such that the thermal expansion and contraction in the radial direction of the honeycomb body 4 of the metal carrier F due to the temperature change of the exhaust gas escapes by the bending of the intermediate body 12.

To compare the manufacturing costs of these various metal carriers relative to each other and to evaluate the durability, the displacement of 200
A 0 cc 4-cycle engine was mounted on the outlet side and a thermal cycle test as shown in FIG. 13 was performed. In the figure, the vertical axis is temperature,
The horizontal axis represents time, and the temperature was measured at a position 20 mm from the upstream end surface of the metal carrier, Temp1 = 150 ° C, Temp2 = 90
0 ° C., T1 = 10 min, T2 = 10 min. The number of test cycles to be achieved is 1000, but in order to relatively evaluate durability, the number of test cycles was extended to 1500 and evaluated.

The production cost comparison and the durability test result are shown in Table 1.
Shown in The number of cycles until the honeycomb body is removed from the outer cylinder is shown. In addition, the judgment was passed if it survived 1000 cycles.

[0035]

[Table 1]

As described above, each of the various metal carriers of the present invention and the conventional various metal carriers for comparison passed the endurance test. The durability is low. Further, although the metal carrier E showed good durability, it has a disadvantage that the manufacturing cost becomes high because the manufacturing process is complicated. On the other hand, the metal carriers A to D of the present invention have a good balance of durability and manufacturing cost and are generally superior to the conventional metal carriers.

[0037]

As described above, according to the present invention,
It was found that by rationalizing the structure of the metal carrier, it is possible to supply a metal carrier that is low in cost and excellent in durability.

[Brief description of drawings]

FIG. 1 is a perspective view showing the appearance of a metal carrier of the present invention.

FIG. 2 is an external perspective view showing an example of each component of the metal carrier of the present invention.

FIG. 3 is a sectional view showing an embodiment (metal carrier A) of the present invention.

FIG. 4 is a sectional view showing an embodiment (metal carrier B) of the present invention.

FIG. 5 is a sectional view showing an embodiment (metal carrier C) of the present invention.

FIG. 6 is a sectional view showing an embodiment (metal carrier D) of the present invention.

FIG. 7 is a cross-sectional view of a metal carrier showing an example of the present invention.

FIG. 8 is a cross-sectional view of a metal carrier showing an embodiment of the present invention.

FIG. 9 is a cross-sectional view of a metal carrier showing an embodiment of the present invention.

FIG. 10 is a cross-sectional view of a metal carrier showing an example of the present invention.

FIG. 11 is a vertical sectional view of a known metal carrier E for comparison with the metal carrier of the present invention.

FIG. 12 is a longitudinal sectional view of a known metal carrier F for comparison with the metal carrier of the present invention.

FIG. 13 is a diagram showing a thermal cycle pattern for evaluating durability of various metal carriers.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Metal carrier 2 Flat foil 3 Corrugated foil 4 Honeycomb body 5 Intermediate body 6 Outer cylinder 7 Joining part between honeycomb body and intermediate body 8 Joining part between intermediate body and outer cylinder 9 Non-bonding part of intermediate body 10 Patterning bonding part Formed honeycomb body 11 joined portion between honeycomb body and outer cylinder 12 intermediate body 13 joined portion between honeycomb body and intermediate body 14 joined portion between intermediate body and outer cylinder

Claims (5)

[Claims] 1. After forming a honeycomb body in which flat foil and corrugated foil are alternately wound or laminated, a thin plate which is the same as or thicker than the foil is wound two or more times on the outside thereof to form an intermediate body, The inner surface of the intermediate body and the honeycomb-to-outer surface are continuously or intermittently made one round, the outer surface of the intermediate body is joined to the outer cylinder within one round, and further, at least one round of non-bonding layer is provided inside the intermediate body. Characteristic metal carrier. 2. The metal carrier according to claim 1, wherein the entire inside of the honeycomb body is joined. 3. The metal carrier according to claim 1, wherein the intermediate body is a flat plate that is not corrugated. 4. The metal carrier according to claim 1, wherein the intermediate is a corrugated corrugated plate. 5. The intermediate body and the honeycomb body are bonded on the upstream side, and the intermediate body and the outer cylinder are bonded on the downstream side.
The metal carrier according to any one of 1 to 4.