JP3272460B2 - Manufacturing method of catalytic converter - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention comprises a monolithic catalyst carrier for supporting a catalyst, a casing accommodating the monolithic 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 comprising a cylindrical carrier holding portion in which a casing holds the monolithic catalyst carrier, and a pair of cone-shaped guide portions connected to both axial ends of the carrier holding portion.

[0002]

2. Description of the Related Art A catalytic converter used as an exhaust gas purifying apparatus for an automobile is composed of a cylindrical monolithic catalyst carrier which carries a catalyst mainly composed of a noble metal such as platinum, rhodium, palladium or the like. Flanges provided at both ends in the axial direction of the casing are connected to flanges provided at an intermediate portion of the exhaust pipe.

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

[0004] First, the outer periphery of a cylindrical monolithic catalyst carrier M is covered by a pair of carrier holding part elements 1 _L and 1 _R divided in the axial direction. type in a state in which along the shape of the catalyst carrier M, to form both the carrier holding portion element 1 _L, 1 welded _R W ₁ and the carrier holding portion 1 cylindrical with (see Figure 5 (a)). At this time, a mat-shaped sealing member 3 is interposed between the monolithic catalyst carrier M and the carrier holding unit 1.

Subsequently, a pair of cone-shaped guide portions 2 and 2 which have been drawn in advance are connected to both axial ends of the carrier holding portion 1 by welding W ₂ to form a casing C (FIG. 5).
(B)). The casing C of the catalytic converter is substantially symmetrical in the front-rear direction, and the rear half thereof is not shown. Finally, both guide portions 2 distal flange coupling portion 2 ₁ of 2 ₁ each flange F, welded F W ₃
To complete the catalytic converter (FIG. 5 (c))
reference). The catalytic converter completed as described above is
It is coupled to flanges Fp, Fp provided on the exhaust pipe P via the flanges F, F at both ends (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]

[SUMMARY OF THE INVENTION Incidentally, since the conventional catalytic converter is a the carrier holding portion 1 and the guide portions 2 is another member constitutes a casing C by welding W ₂ together, There is a problem that a step is generated near the welded portion and the flow of the exhaust gas is hindered, and the exhaust gas hardly hits the outer peripheral portion of the monolithic catalyst carrier M. In addition, the number of parts of the casing C increases and the cost increases There is a problem to do.

Therefore, it is conceivable to form the carrier holding portion 1 and the guide portions 2 and 2 integrally to make the flow of the exhaust gas smooth. However, since the guides 2 and 2 need to be divided into two parts along the axial direction together with the carrier holding part 1 as described above, the two divided elements are pressurized according to the shape of the monolithic catalyst carrier M. , in welding by overlapping the junction of the two elements, the flange coupling portion 2 ₁ formed at the distal end of the guide portion 2,2, 2 variation occurs in the _first diameter flange F, F welding There is a problem that hinders.

The present invention has been made in view of the above-mentioned circumstances, and provides a method of manufacturing a catalytic converter capable of smoothly guiding exhaust gas to a monolith-type catalyst carrier and having a flange coupling portion having precise dimensions. The purpose is to provide.

[0010]

To achieve the above object, the present invention provides a monolithic catalyst carrier for supporting a catalyst,
A casing accommodating a monolithic catalyst carrier therein, and a pair of flanges coupled to both ends in the axial direction of the casing, wherein the casing holds a cylindrical carrier holding section that holds the monolithic catalyst carrier; and a carrier holding section. the method of manufacturing a catalytic converter comprised of a guide portion of a pair of tapered connecting to both axial ends of a plurality of casing elements obtained by dividing along the casing in the axial direction, their casings
Parts of the locking element corresponding to the pair of guide portions are from the base end.
It is formed to taper over the entire length up to the tip.
And a step of integrally coupling the plurality of casing elements with the monolithic catalyst carrier housed inside the carrier holding portion, and a step of integrally coupling the plurality of casing elements together . Point of tapered guide
It is subjected to plastic working to the end, to a step of forming a short cylindrical flange coupling portion to the tip, characterized by comprising the step of coupling the flange to the flange joint.

[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 longitudinal sectional view of the catalytic converter, and FIG. FIG. 4 is a diagram showing a method for manufacturing the catalytic converter.

As shown in FIGS. 1 to 3, a catalytic converter includes a casing C containing a monolithic catalyst carrier M therein.
And a pair of flanges F, F connected to both ends in the axial direction of the casing C. The completed casing C is composed of a central carrier holding portion 1 and a pair of guide portions 2 and 2 provided at both ends in the axial direction of the carrier holding portion 1, and is divided into two along the axial direction. A pair of casing elements C _L , C
Formed by bonding together the _R by welding W _1. Accordingly, each of the casing elements C _L and C _R is composed of a half of the carrier holding portion 1 and a half of the two guide portions 2 and 2 connected thereto. The monolithic catalyst carrier M is a mat-shaped sealing member 3
Is held inside the carrier holding portion 1 of the casing C via the

[0014] Each guide portions 2 is tapered tapered from the portion connected to the carrier holding portion 1, the flange coupling portions 2 ₁ a short cylindrical shape formed at its front end, 2 _1, flange F respectively, F There are joined by welding W _3.

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

First, the monolithic catalyst carrier M is covered with a pair of two divided casing elements C _L and C _R and pressurized inward so that a uniform surface pressure is applied to the outer periphery of the monolithic catalyst carrier M. After molding, a pair of casing elements C _L , C
Spot welding _R at a plurality of locations W ₀ to be temporarily fixed (Fig. 4
(A)).

Next, while holding the outer peripheries of the pair of casing elements C _L and C _R and one end surface thereof, the other end surface is plastically worked, and a short cylindrical flange connecting portion is attached to the tip of the tapered guide portion 2. to form a 2 ₁ (see FIG. 4 (b), (c) ).
The processing of the flange coupling portions 2 ₁ is carried out while rotating the casing C about the axis, the flange coupling portion 2 ₁ to the end surface of both of the casing C, 2 ₁ are processed. Finally, after the flanges F, F are respectively connected to the flange connection portions 2 ₁ , 2 ₁ by welding W ₃ (see FIG. 4D), a pair of temporary fixings by spot welding W ₀ until then. 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 and the guide portions 2 and 2 of the casing C are integrally formed, a step may be generated at the connecting portion between the carrier holding portion 1 and the guide portions 2 and 2. And the cross-sectional shape in the vicinity of the joint changes smoothly. Therefore, the exhaust gas introduced from the exhaust pipe P to the front guide portion 2 smoothly flows into the carrier holding portion 1,
The monolith-type catalyst carrier M held therein is uniformly contacted. The exhaust gas purified by passing through the monolithic catalyst carrier M smoothly flows from the carrier holding unit 1 into the rear guide unit 2 and is discharged to the exhaust pipe P. After the casing elements C _L and C _R are connected to each other,
₁ and 2 ₁ are plastically processed, so that the flange joints 2 ₁ and 2 ₁ can be finished to precise dimensions.
The connection of the flanges F, F can be easily performed. In addition, since the carrier holder 1 and the guides 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 as follows. That is, the pair of casing element that covers the monolithic catalyst support M C _L, the flange coupling portion 2 _1, 2 ₁ remains pressurized inwardly the C _R and plastic working,
Flange F as it is, the weld W ₃ and a pair of casing element C _L of F, may be performed welding W ₁ of the entire circumference of the C _R.

[0020] As still another processing procedure, the pair of casing element that covers the monolithic catalyst support M C _L, after the entire circumference remain pressurized inwardly the C _R and welding W _1, to both ends of the casing The flanges F 1 and F 2 may be welded W ₃ by plastically processing the flange joints 2 ₁ and 2 ₁ .

Although the embodiments of the present invention have been described in detail, 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. However, the casing C can be divided into three or more.

[0023]

As described above, according to the present invention, a plurality of casing elements obtained by dividing a casing accommodating a monolithic catalyst carrier therein in the axial direction are provided inside the carrier holding portion. Since the catalyst carrier is housed and joined together, there is no step between the carrier holding part and the guide part of the casing, so that the flow of exhaust gas inside the casing is smooth and the exhaust gas is transferred to the monolithic catalyst carrier. Not only can uniform and efficient contact be achieved, but also the cost can be reduced by reducing the number of parts of the casing. Was duck plurality of casing elements, their essential
The part of the element corresponding to the pair of guides is from the base end to the tip
It is formed so as to taper over the entire length.
With the number of casing elements joined together,
Plastic processing at the tip of the tapered guide part of
Since a short cylindrical flange joint is formed at the tip,
At the end of the tapered guide during the manufacturing stage of various casing elements
After machining the flange connection, the casing elements are
The diameter of the flange joint
Rutting can be effectively suppressed, and thus the flange connection portion can be finished to precise dimensions to facilitate the flange connection operation.

[Brief description of the drawings]

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

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

FIG. 3 is a sectional view taken along line 3-3 in FIG. 2;

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

FIG. 5 is a view showing a method for manufacturing a conventional catalytic converter.

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

[Explanation of symbols]

C casing C _L casing element C _R casing element F Flange M Monolithic catalyst carrier 1 Carrier holding section 2 Guide section 2 ₁ Flange connection section

──────────────────────────────────────────────────続 き Continued on the front page (72) Inventor Koichi Fujimori 1-4-1 Chuo, Wako-shi, Saitama Pref. Inside Honda R & D Co., Ltd. (56) References JP-A-4-234517 (JP, A) Jikken Sho 57-24892 (JP, Y1) (58) Fields surveyed (Int. Cl. ⁷ , DB name) ) F01N 3/24-3/28

Claims (1)

(57) [Claims] 1. A monolithic catalyst carrier (M) supporting a catalyst, a casing (C) accommodating the monolithic catalyst carrier (M) therein, and a pair of axially opposite ends of the casing (C). A cylindrical carrier holding portion (1) having a flange (F), wherein the casing (C) holds the monolithic catalyst carrier (M), and a pair of axially opposite ends of the carrier holding portion (1). the method of manufacturing a catalytic converter comprised of the guide portion of the tapered and (2), said plurality of casing element the casing (C) formed by dividing along the axial direction (C _L, C _R), and their casings
Grayed element (C _L, C _R) of the pair to the pair of guide portions (2)
The corresponding part tapers over the entire length from the base to the tip
Forming a plurality of casing elements (C _L , C _R ) together with the monolithic catalyst carrier (M) housed in the carrier holding part (1). Process and combining the plurality of casing elements ( _CL , _CR ) together
The pair of tapered guides (2)
Tip is subjected to plastic working into the bond forming a short cylindrical furan <br/> di coupling portion (2 ₁₎ to the tip, the flange (F) on the flange coupling portions (2 ₁₎ And a method of manufacturing a catalytic converter.