JPH06129248A - Manufacture of catalytic converter - Google Patents

Abstract

PURPOSE:To easily incorporate the catalyst carrier of a catalytic converter into converter cases and also to reliably hold it without its movement. CONSTITUTION:A ceramic adhesive 14 is applied on the outer peripheral surface of a catalyst carrier 8, and a cylindrical corrugate mesh member 11 is fitted to the outer periphery of the catalyst carrier 8 before the adhesive 14 is hardened. Thereby the irreguralities are formed by those of the corrugate mesh member 11. And the irregularities remain as they are also after the adhesive 14 is hardened. Thus, a catalytic converter is formed by incorporating the catalyst carrier 8 on which the corrugate mesh member 1 is stuck into converter cases 2a, 2b.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for manufacturing a catalytic converter used for purifying exhaust gas discharged from an automobile engine or the like, and more particularly to manufacturing a catalytic converter using a honeycomb-structured catalyst carrier. It is about the method.

[0002]

2. Description of the Related Art In automobiles, a catalytic converter is often provided in the exhaust system in order to remove harmful components in the exhaust gas discharged from the engine. A catalytic converter is a converter case in which a three-way catalyst such as platinum, rhodium, or palladium is supported in a converter case through which exhaust gas flows, and harmful components in the exhaust gas pass through the catalytic converter. It is purified by being oxidized or reduced by the internal catalyst. A monolith type is widely used as such a catalytic converter. In the catalytic converter, a honeycomb structured columnar body made of a ceramic such as alumina is used as a catalyst carrier. The catalyst is supported by coating the inner surface of the catalyst carrier. And
The catalyst carrier is arranged axially in a cylindrical converter case through which exhaust gas flows axially. According to such a catalytic converter, since the amount of catalyst carried per fixed volume is large, the purification efficiency is high, the heat capacity is small, the purification start at the cold start is fast, and the ventilation resistance per the same flow passage cross-sectional area is low. Since the catalyst carrier has an integral structure, the converter has a simple structure.

By the way, in such a catalytic converter, it is required that the catalyst carrier is securely held so as not to move in the radial direction and come into contact with the converter case. Therefore, generally, a holding material is provided between the outer peripheral surface of the catalyst carrier and the inner peripheral surface of the converter case, and the catalyst carrier is supported by the converter case via the holding material. In that case, hot exhaust gas flows into the catalytic converter. Moreover, since the components in the exhaust gas cause a chemical reaction by the catalyst, the reaction heat is also generated. Therefore, the temperature of the catalytic converter becomes extremely high. Therefore, both the catalyst carrier and the converter case in the catalytic converter thermally expand. The coefficient of thermal expansion of the catalyst carrier made of ceramic is much smaller than that of the converter case made of metal, and thus the difference in thermal expansion causes a large gap between the converter case and the catalyst carrier. The catalyst carrier must be held securely at such times. Further, at that time, the exhaust gas should not flow between the outer peripheral surface of the catalyst carrier and the inner peripheral surface of the converter case.
Therefore, as a holding material for holding the catalyst carrier, a corrugated mesh material formed by knitting metal fibers such as stainless steel and a seal material having a cushioning property and thermally expanding are used.

When manufacturing such a catalytic converter, conventionally, the catalytic converter has a high temperature as described above, and the adhesive deteriorates due to the heat, so that the adhesive cannot be used for its manufacture. Was considered. Then, the corrugated mesh material has a cylindrical shape and is simply fitted onto the outer periphery of the catalyst carrier and incorporated into the converter case.

[0005]

However, an axial force is also applied to the catalyst carrier by the pressure of the exhaust gas.
Therefore, in the case of the catalytic converter using the columnar catalyst carrier as described above, a means for regulating the axial movement of the catalyst carrier is required. In that case, in the catalytic converter in which the corrugated mesh material is simply fitted around the outer periphery of the catalyst carrier as described above, the force acting between the catalyst carrier and the holding material is only frictional force. Since the catalyst carrier having the honeycomb structure is usually formed by extrusion molding, its outer peripheral surface is smooth. Further, recently, the density of the ceramic catalyst carrier tends to be lowered in order to increase the purification rate by the catalyst, and if the holding material is strongly pressed against the catalyst carrier, the pressure applied during the assembling to the converter case causes the catalyst carrier. Therefore, the pressing force applied from the holding material to the catalyst carrier is reduced. As a result, the frictional force acting between the catalyst carrier and the holding material is small. Therefore, it is difficult to suppress axial movement and rotation of the catalyst carrier in the conventional catalytic converter.

[0006] From the above, for example, the actual Kaisho 50-
As shown in Japanese Patent No. 27220, it is considered to form irregularities on the outer peripheral surface of the catalyst carrier. However, in order to form the unevenness on the outer peripheral surface of the catalyst carrier as described above, for example, after applying the base slurry to the outer peripheral surface of the catalyst carrier by a coating roller or the like, the unevenness is formed on the surface by sandblasting or the like and dried. After that, a process of applying an overcoat and baking it is necessary. Therefore, there is a problem that the number of processing steps increases and the manufacturing cost thereof increases.

The present invention has been made in view of the above circumstances, and an object thereof is to manufacture a catalytic converter which can surely hold a catalyst carrier only by adding a simple process. To get a way.

[0008]

To achieve this object, in the present invention, a ceramic adhesive is applied to the outer peripheral surface of the catalyst carrier, and the outer periphery of the catalyst carrier is coated before the adhesive is cured. The corrugated mesh material is attached to and is incorporated into the converter case.

[0009]

With this construction, the corrugated mesh material is bonded to the outer peripheral surface of the catalyst carrier. Then, at that time, unevenness is formed on the adhesive layer by the unevenness of the corrugated mesh material. The unevenness remains even after the adhesive is cured. Therefore, the friction coefficient between the catalyst carrier and the corrugated mesh material becomes large, and even if the adhesive force due to the adhesive decreases due to heat or aging, the catalyst carrier can be securely held at that position. become.

[0010]

Embodiments of the present invention will be described below with reference to the drawings. 1 is a cutaway perspective view showing an overall structure of a catalytic converter to which the present invention is applied, and FIG. 2 is an explanatory view showing an embodiment of a method for manufacturing a catalytic converter according to the present invention. Further, FIG. 3 is an enlarged cross-sectional view of a main part for explaining the operation. As shown in FIG. 1, the catalytic converter 1 includes a converter case 2. The converter case 2 has a tapered exhaust gas introduction part 4 and a tapered exhaust part 5 in front of and behind a cylindrical center case 3 having irregularities.
Is continuously provided and is divided into two parts, that is, the upper part and the lower part are divided into two parts, and the divided parts 2a and 2b are faced to each other and joined together. The converter case 2 is provided with exhaust gas introduction ports 6 and exhaust ports 7 at the front and rear ends, respectively, and by connecting exhaust pipes (not shown) to the introduction ports 6 and the exhaust ports 7, respectively, from the front end side thereof. The exhaust gas flows in, flows in the axial direction, and flows out from the rear end.

Inside the center case 3, a cylindrical catalyst carrier 8 is axially arranged. The catalyst carrier 8 has a honeycomb structure made of ceramic, and has a large number of small holes 9, 9 ... The small hole 9,
The inner peripheral surfaces of 9, ... Are coated with a three-way catalyst such as platinum or rhodium. Exhaust gas has its small holes 9, 9,
It is designed to be oxidized or reduced by passing through the inside and contacting the catalyst in the meantime. Sealing materials 10, 10 are wound around the front and rear ends of the outer periphery of the catalyst carrier 8. The sealing material 10 is formed by adding a binder to a mixture of ceramic fibers and vermiculite to form a band, and thermally expands when heated to a temperature of 250 to 350 ° C. to exhibit cushioning properties. The sealing material 10 seals between the outer peripheral surface of the catalyst carrier 8 and the inner peripheral surface of the center case 3. Further, on the outer periphery of the catalyst carrier 8, a corrugated mesh material 11 is provided between the seal materials 10 at both ends.
Is attached. The mesh material 11 has a cylindrical shape formed by weaving stainless steel fibers having a diameter of about 0.25 to 0.30 mm, and is fitted on the outer periphery of the catalyst carrier 8 with an adhesive. Then, when the catalyst carrier 8 is incorporated into the converter case 2, the corrugated mesh material 11 has the converter case 2 and the catalyst carrier 8.
It is designed to be compressed between and. In this way, the catalyst carrier 8 is elastically supported by the center case 3 of the converter case 2 via the holding material composed of the seal materials 10, 10 and the corrugated mesh material 11.

When manufacturing such a catalytic converter 1, first, as shown in FIG. 2A, a jig 12 is attached on the central axis of the catalyst carrier 8, and the catalyst is moved by the jig 12. While rotating the carrier 8, the adhesive 14 is applied to the outer peripheral surface of the carrier 8 by the adhesive applying roller 13 or the like.
As the adhesive 14, a ceramic adhesive containing ceramic particles, for example, a slurry obtained by kneading cordierite with water and a binder, or a product name “Aron Ceramic” manufactured by Toagosei Chemical Industry Co., Ltd. is used. ,
Apply it to a thickness of about 5 mm. The curing temperature of the adhesive 14 is lower than the expansion temperature of the sealing material 10. Then, before the adhesive 14 is cured, as shown in FIG.
As shown in (B), the cylindrical corrugated mesh material 11 is formed on the catalyst carrier 8 to which the adhesive 14 is applied.
Fit in. Further, the seal materials 10 and 10 are wound around both sides of the corrugated mesh material 11 and temporarily fixed. Then, the catalyst carrier 8 to which the seal materials 10 and 10 and the corrugated mesh material 11 are attached in this way is attached to the adhesive 14
The adhesive 14 is hardened by heating to the hardening temperature. Thereby, the sealing material 10 and the corrugated mesh material 1
1 is adhered to the outer peripheral surface of the catalyst carrier 8. After that, the catalyst carrier 8 to which the seal material 10 and the corrugated mesh material 11 are attached in this way is divided into the divided bodies 2a, 2 of the converter case 2 from both sides as shown in FIG. 2 (C).
It is sandwiched by b and the divided bodies 2a and 2b are connected to each other. As a result, the catalyst carrier 8 becomes the converter case 2
Incorporated therein to form the catalytic converter 1. In that case, the corrugated mesh material 11 is the converter case 2
And the catalyst carrier 8 are compressed. Therefore, the catalyst carrier 8 is elastically held by the converter case 2 via the corrugated mesh material 11.

When the catalytic converter 1 thus formed is attached to the exhaust system of the engine and the engine is started, high-temperature exhaust gas flows in the catalytic converter 1 to heat the sealing materials 10, 10. It The heat causes the sealing material 10 to expand, and the catalyst carrier 8
The outer peripheral surface of the converter and the inner peripheral surface of the converter case 2 are sealed. Once expanded, the sealing material 10 does not shrink even if the temperature decreases. Therefore, the seal by the sealing material 10 is maintained thereafter. Moreover, since the sealing material 10 has a cushioning property, even if the size of the gap between the converter case 2 and the catalyst carrier 8 changes due to the difference in thermal expansion, the sealing property is not impaired. Since the catalyst carrier 8 and the converter case 2 are thus sealed, the exhaust gas flowing from the exhaust gas introduction port 6 of the converter case 2 flows through the small holes 9, 9, ... Of the catalyst carrier 8. The small hole 9
It is oxidized or reduced by coming into contact with the catalyst carried on the inner peripheral surface thereof. In this way, harmful components in the exhaust gas are purified.

According to the method of manufacturing the catalytic converter 1 as described above, the corrugated mesh material 11 which is a holding material for the catalyst carrier 8 is adhered to the catalyst carrier 8, so that the corrugated mesh material 11 is placed on the outer peripheral surface of the catalyst carrier 8. Is prevented from sliding along. Further, since the sealing material 10 is also adhered to the catalyst carrier 8, the divided bodies 2a, 2 of the converter case 2 are
When sandwiched from both sides by b, the divided body 2a,
The sealing material 10 is also prevented from being caught between the 2b.
Therefore, the work of assembling the catalyst carrier 8 to the converter case 2 becomes extremely easy. Furthermore, by attaching the corrugated mesh material 11 before the adhesive 14 is cured, the adhesive 14 has irregularities as shown in FIG. Then, the adhesive 14 is cured in that state. Moreover, since the adhesive 14 is made of the same ceramic as the catalyst carrier 8, it does not peel off from the catalyst carrier 8 due to a difference in thermal expansion. Therefore, even if the adhesive force of the adhesive 14 to the corrugated mesh material 11 is lost due to heat of the exhaust gas or change with time, the corrugated mesh material 11 is caused by the frictional force between them.
Are prevented from moving with respect to the catalyst carrier 8. On the other hand, the movement of the corrugated mesh material 11 with respect to the converter case 2 is prevented by the engagement of the unevenness on the outer periphery thereof and the unevenness of the center case 3. As a result, the movement of the catalyst carrier 8 with respect to the converter case 2 is restricted, and the catalyst carrier 8 is prevented from moving in the axial direction due to the pressure of exhaust gas or the like. Thus, the catalyst carrier 8 is securely held at that position by the seal material 10 and the corrugated mesh material 11, and the space between the catalyst carrier 8 and the converter case 2 is surely sealed.

In the above embodiment, both the sealing material 10 and the corrugated mesh material 11 which are holding materials are adhered to the catalyst carrier 8, but the sealing material 10
May not be glued. In that case,
The corrugated mesh material 11 may be attached to the catalyst carrier 8 while the adhesive 14 is in a flexible state, the catalyst carrier 8 may be heated to cure the adhesive 14, and then the sealing material 10 may be attached. By doing so, the adhesive 1
As 4, it is possible to use one having a higher curing temperature.

[0016]

As is apparent from the above description, according to the present invention, the corrugated mesh material for holding the catalyst carrier is adhered to the outer peripheral surface of the catalyst carrier by the adhesive, so that the catalyst carrier is It becomes easy to incorporate the holding material into the converter case. Further, since it suffices to add the step of applying the ceramic adhesive to the outer peripheral surface of the catalyst carrier, the manufacturing cost of the catalytic converter can be kept low. Then, by manufacturing the catalytic converter in this manner, the catalyst carrier can be reliably held, so that the durability of the catalytic converter can be enhanced.

[Brief description of drawings]

FIG. 1 is a cutaway perspective view showing an example of a catalytic converter to which the present invention is applied.

FIG. 2 is an explanatory view showing an embodiment of a method for manufacturing a catalytic converter according to the present invention.

FIG. 3 is an enlarged cross-sectional view of a main part for explaining the operation of the catalytic converter manufactured as shown in FIG.

[Explanation of symbols]

 1 Catalytic Converter 2 Converter Case 8 Catalyst Carrier 10 Sealing Material (Holding Material) 11 Corrugated Mesh Material (Holding Material) 14 Adhesive

Claims (1)

[Claims] 1. A ceramic catalyst carrier having a honeycomb structure carrying a catalyst is coated with a ceramic adhesive containing ceramic particles, and the corrugated mesh is formed on the outer periphery of the catalyst carrier before the adhesive is cured. A method of manufacturing a catalytic converter, which comprises attaching a material and incorporating the catalyst carrier to which the corrugated mesh material is adhered into a converter case.