JPH06288234A - Manufacture of catalytic converter - Google Patents

Abstract

PURPOSE:To form a casing to store a monolith type catalyzer support of a catalytic converter with a small number of parts e in a smooth shape in which exhaust gas easily flows and to finish its flange joint part in precise measurement. CONSTITUTION:A casing C furnished with a support holding part 1 to store a monolith type catalyzer support M and a pair of guide parts 2 connectively provided on both ends in its axial direction and to guide exhaust gas is constituted by integrally welding W1 a pair of casing elements CL, CR divided into two along the axial direction. On head ends of the guide parts 2, flange joint parts 21 are formed in machining, and on the flange joint parts 21, a flange F connected to an exhaust pipe P is jointed by welding W3.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention comprises a monolith-type catalyst carrier carrying a catalyst, a casing containing the monolith-type catalyst carrier therein, and a pair of flanges connected to both axial ends of the casing. The present invention relates to a method for manufacturing a catalytic converter, in which a casing includes a cylindrical carrier holding portion holding the monolith-type catalyst carrier, and a pair of cone-shaped guide portions connected to both ends of the carrier holding portion in the axial direction.

[0002]

2. Description of the Related Art A catalytic converter used as an exhaust gas purifying apparatus for automobiles has a cylindrical monolith type catalyst carrier carrying a catalyst whose main component is a noble metal such as platinum, rhodium, and paradium, and has a metal casing. It is housed inside, and flanges provided at both axial ends of the casing are joined to flanges provided at an intermediate portion of the exhaust pipe.

A conventional method for manufacturing a catalytic converter will be described with reference to FIG.

First, the outer periphery of a cylindrical monolith-type catalyst carrier M is covered with a pair of carrier holding part elements 1 _L and 1 _{R which} are divided into two along the axial direction, and inward pressure is applied to the surface of the monolith-type catalyst carrier M to form the monolith. In a state of conforming to the shape of the type catalyst carrier M, the two carrier holding part elements 1 _L and 1 _R are welded W ₁ to form the cylindrical carrier holding part 1 (see FIG. 5A). At this time, a mat-shaped seal member 3 is interposed between the monolith type catalyst carrier M and the carrier holding portion 1.

Subsequently, a pair of cone-shaped guide portions 2 and 2 which have been previously drawn are joined to both ends in the axial direction of the carrier holding portion 1 by welding W ₂ to form a casing C (FIG. 5).
(See (b)). The casing C of the catalytic converter is substantially symmetrical in the front-rear direction, and the latter half of the casing is not shown. Finally, the flanges F and F are welded to the flange joints 2 ₁ and 2 ₁ at the tips of the guides 2 and 2 by welding W _{3 respectively.}
To complete the catalytic converter (Fig. 5 (c)).
reference). The catalytic converter completed as described above is
It is connected to the flanges Fp, Fp provided on the exhaust pipe P via the flanges F, F at both ends thereof (see FIG. 5D).

[0006] Figure 6 shows another conventional example of a method of manufacturing a catalytic converter, the conventional example in the shape of the portion to be welded W ₂ and a guide portion 2,2 and the carrier holding portion 1, the above-described FIG. 5 Is different from the conventional example.

[0007]

By the way, in the above-mentioned conventional catalytic converter, since the carrier holding portion 1 and the guide portions 2 and 2 which are separate members are integrally welded W ₂ to form the casing C, There is a problem that a step is generated in the vicinity of the welded portion and the flow of the exhaust gas is obstructed, and it becomes difficult for the exhaust gas to hit the outer peripheral portion of the monolith-type catalyst carrier M. Moreover, the number of parts of the casing C increases and the cost increases. I have a problem to do.

Therefore, it can be considered that the carrier holding portion 1 and the guide portions 2 and 2 are integrally formed to make the flow of exhaust gas smooth. However, in the above-described manner, since the guide portions 2 and 2 need to be divided into two along with the carrier holding portion 1 along the axial direction, the two divided elements are pressed according to the shape of the monolith-type catalyst carrier M. , When the connecting portions of the two elements are overlapped and welded, the flange connecting portions 2 ₁ , 2 ₁ formed at the tips of the guide portions 2, 2 have variations in diameter, and the flanges F, F are welded. There is a problem that interferes with.

The present invention has been made in view of the above circumstances, and provides a method for manufacturing a catalytic converter that can smoothly guide exhaust gas to a monolithic catalyst carrier and that has a flange joint portion with precise dimensions. The purpose is to provide.

[0010]

In order to achieve the above-mentioned object, the present invention provides a monolith type catalyst carrier carrying a catalyst,
A casing for accommodating the monolithic catalyst carrier therein, and a pair of flanges connected to both ends in the axial direction of the casing, wherein the casing has a cylindrical carrier holder for holding the monolithic catalyst carrier, and a carrier holder. In a method for manufacturing a catalytic converter comprising a pair of cone-shaped guide portions connected to both ends in the axial direction, a plurality of casing elements formed by dividing the casing in the axial direction are provided inside the carrier holding portion in a monolith type. The method further comprises a step of integrally coupling the catalyst carrier in a housed state, a step of processing a flange coupling portion at a pair of guide portion tips of the casing integrally coupled, and a step of coupling the flange to the flange coupling portion. It is characterized by

[0011]

Embodiments of the present invention will be described below with reference to the drawings.

1 to 4 show an embodiment of the present invention. FIG. 1 is an overall perspective view of a catalytic converter, FIG. 2 is a partial vertical cross-sectional view of the catalytic converter, and FIG. 3 is 3-3 of FIG. FIG. 4 is a sectional view taken along the line, showing a method for manufacturing the catalytic converter.

As shown in FIGS. 1 to 3, the catalytic converter has a casing C containing a monolithic catalyst carrier M therein.
And a pair of flanges F, F connected to both ends of the casing C in the axial direction. The completed casing C is composed of a center carrier holding portion 1 and a pair of guide portions 2 and 2 which are continuously provided on both ends of the carrier holding portion 1 in the axial direction, and is divided into two along the axial direction. A pair of casing elements C _L , C
_{It is formed by connecting R} together by welding W ₁ . Therefore, each casing element C _L , C _R is composed of a half of the carrier holding part 1 and a half of the two guide parts 2, 2 connected to it. The monolithic catalyst carrier M is a mat-shaped seal member 3
It is held inside the carrier holding portion 1 of the casing C via.

Each of the guide portions 2 and 2 is tapered from a portion connected to the carrier holding portion 1, and flanges F and F are respectively attached to short cylindrical flange coupling portions 2 ₁ and 2 ₁ formed at the tips thereof. Are joined by welding W ₃ .

Next, a method of manufacturing the catalytic converter will be described with reference to FIG.

First, the monolithic catalyst carrier M is covered with a pair of casing elements C _L and C _R which are divided into two parts, and the monolithic catalyst carrier M is pressurized inward so that a uniform surface pressure is applied to the outer periphery thereof. After molding, the pair of casing elements C _L , C
Spot welding W ₀ at multiple points to temporarily fix _R (Fig. 4
(See (a)).

Next, while holding the outer peripheries of the pair of casing elements C _L and C _R and one end face thereof, the other end face is subjected to plastic working, and a short cylindrical flange coupling portion is formed at the tip of the tapered guide portion 2. 2 ₁ is formed (see FIGS. 4B and 4C).
The processing of the flange connecting portion 2 ₁ is performed while rotating the casing C around the axis, and the flange connecting portions 2 ₁ and 2 ₁ are processed on both end surfaces of the casing C. And finally, after the flanges F, F are connected to the flange connecting portions 2 ₁ , 2 ₁ by welding W ₃ respectively (see FIG. 4 (d)), the pair of flanges which have been temporarily fixed by spot welding W ₀ until then are joined. The casing elements C _L and C _R are welded W ₁ over the entire circumference to complete the catalytic converter shown in FIG.

Since the carrier holding portion 1 of the casing C and the guide portions 2 and 2 are integrally formed, a step may occur at the connecting portion between the carrier holding portion 1 and the guide portions 2 and 2. It disappears, and the cross-sectional shape near the joint changes smoothly. Therefore, the exhaust gas introduced from the exhaust pipe P into the front guide portion 2 smoothly flows into the carrier holding portion 1,
The monolithic catalyst carrier M held therein uniformly contacts. Then, the exhaust gas purified by passing through the monolith catalyst carrier M smoothly flows into the rear guide portion 2 from the carrier holding portion 1 and is discharged to the exhaust pipe P. In addition, after connecting the casing elements C _L and C _R to each other, the flange connecting portion 2
_{Since 1} and 2 ₁ are plastically machined, the flange joints 2 ₁ and 2 ₁ can be finished to precise dimensions,
The flanges F and F can be easily connected. Moreover, since the carrier holding portion 1 and the guide portions 2 and 2 are integrally formed, the number of parts is reduced and the manufacturing cost of the catalytic converter can be reduced.

The processing procedure of the catalytic converter can be performed as follows. That is, the flange coupling portions 2 ₁ and 2 ₁ are plastically worked while the pair of casing elements C _L and C _R covering the monolith catalyst carrier M are pressed inward,
The welding W ₃ of the flanges F and F and the welding W ₁ of the entire circumference of the pair of casing elements C _L and C _R may be performed in that state.

As still another processing procedure, a pair of casing elements C _L and C _R covering the monolith type catalyst carrier M are welded W _{1 along the} entire circumference while being pressed inward, and then the both ends of the casing are welded. The flange coupling portions 2 ₁ and 2 ₁ may be plastically worked and the flanges F and F may be welded W ₃ .

Although the embodiments of the present invention have been described in detail above, the present invention is not limited to the above embodiments, and various design changes can be made.

For example, in the embodiment, the casing C is divided into two along the axial direction, but it is also possible to divide into three or more.

[0023]

As described above, according to the present invention, a plurality of casing elements formed by dividing a casing for accommodating a monolith type catalyst carrier therein in the axial direction are provided in the carrier holding portion of the monolith type. Since the catalyst carriers are integrally connected in a state where they are housed, the step between the carrier holding part and the guide part of the casing is eliminated to smooth the flow of exhaust gas inside the casing, and the exhaust gas is converted into a monolith type catalyst carrier. Not only is it possible to make uniform and efficient contact, but also the number of parts of the casing can be reduced to reduce costs. In addition, since the flange connecting portion is processed at the tip of the guide portion of the integrally connected casing, the flange connecting portion can be finished to precise dimensions to facilitate the flange connecting operation.

[Brief description of drawings]

FIG. 1 is an overall perspective view of a catalytic converter.

FIG. 2 is a partial vertical sectional view of a catalytic converter.

3 is a sectional view taken along line 3-3 of FIG.

FIG. 4 is a diagram showing a method for manufacturing a catalytic converter.

FIG. 5 is a diagram showing a method of manufacturing a conventional catalytic converter.

FIG. 6 is a view showing another manufacturing method of the conventional catalytic converter.

[Explanation of symbols]

C casing C _L casing element C _R casing element F Flange M Monolith type catalyst carrier 1 Carrier holding part 2 Guide part 2 ₁ Flange coupling part

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Koichi Fujimori Inventor Koichi Fujimori 1-4-1 Chuo, Wako-shi, Saitama, Ltd. Honda R & D Co., Ltd. Yutaka Giken Tochigi Technology Center Co., Ltd.

Claims (1)

[Claims] 1. A monolith type catalyst carrier (M) carrying a catalyst, a casing (C) containing the monolith type catalyst carrier (M) therein, and a pair of axially opposite ends of the casing (C). A cylindrical carrier holding part (1) having a flange (F), and the casing (C) holding the monolithic catalyst carrier (M), and a pair of axially opposite ends of the carrier holding part (1). the method of manufacturing a catalytic converter comprised of a cone-shaped guide portion (2), said plurality of casing element the casing (C) formed by dividing along the axial direction (C _L, C _R) and its carrier holding portion (1) a step of integrally joining the monolithic catalyst carrier (M) in a housed state, and a pair of guide portions (2) of the integrally joined casing (C) with a flange joint portion (2 ₁ ) Processing and flange connection Parts characterized by comprising the step of coupling the flange (F) to (2 _1), the manufacturing method of the catalytic converter.