JP2002201932A - Method of manufacturing catalytic converter - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method of manufacturing a catalytic converter capable of easily press-fitting a catalyst carrier into a holding tube. SOLUTION: When the catalyst carrier 2 is press-fitted into the holding tube 1', a diverged diameter part 14 diverging from a center side toward one end part side is formed at one end part of the holding tube 1' beforehand. The catalyst carrier 2 having a holding material 3 and meshes 4 installed on the outer periphery thereof is press-fitted into the holding tube 1' from the diverged diameter part 14.

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 for purifying vehicle exhaust gas.

[0002]

2. Description of the Related Art Generally, when manufacturing a catalytic converter in which a catalyst carrier is fixed to the inner periphery of a holding cylinder via a holding material such as a non-expansion mat, first, a ring shape is formed on the outer periphery of the catalyst carrier. Attach the holding material. Next, the catalyst carrier with the holding material is inserted into the holding cylinder. The inner diameter of the holding cylinder is equal to or larger than the outer diameter of the holding material wound around the catalyst carrier,
The catalyst carrier can be easily inserted into the holding cylinder. After the insertion of the catalyst carrier, the diameter of the holding cylinder is reduced by spinning or the like. As a result, the catalyst carrier is fixed to the holding cylinder, and a catalytic converter is manufactured (see JP-A-2000-45762).

[0003]

In the catalytic converter manufactured as described above, since the holding cylinder vibrates during spinning for reducing the diameter of the holding cylinder, the catalyst carrier is displaced in the axial direction of the holding cylinder. Otherwise, there is a possibility that an excessive pressure is applied to a part of the catalyst support and the catalyst support is cracked therefrom.

[0004]

In order to solve the above-mentioned problems, the present invention provides a method for press-fitting a catalyst carrier into a holding cylinder, the center of which is provided at the end of the holding cylinder on which the catalyst carrier is inserted. It is characterized in that an enlarged diameter portion is formed in advance to increase the diameter toward the end.

[0005]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments of the present invention will be described below with reference to FIGS. First, the first of the catalytic converters to be manufactured by the manufacturing method of the present invention is described.
1 will be described with reference to FIG. 1. The catalytic converter A shown in FIG. 1 includes a holding cylinder 1 and a catalyst carrier 2.
The holding tube 1 is a metal tube having a circular cross section with both ends opened, and a fixed portion 11 having a constant diameter is formed at the center in the axial direction, and the both ends are arranged from the center to the end. Diffuser parts 12 and 12 whose diameter decreases as going to
Are formed. A bent portion 13 is formed between the fixed portion 11 and the diffuser portion 12, and is bent substantially perpendicularly inward in the radial direction from the fixed portion 11 to reach the diffuser portion 12.

[0006] As is well known, the catalyst carrier 2 is made of a porous ceramic or honeycomb structure, and inside thereof is provided a small piece (not shown) of a noble metal or a noble metal and a base metal serving as a catalyst. A cylindrical holding member 3 made of a non-expandable mat or the like is mounted on the outer peripheral surface of the catalyst carrier 2 except for both end portions. On the outer peripheral surfaces of both ends of the catalyst carrier 2,
A mesh 4 formed in a ring shape by randomly gathering thin and long strip-shaped wires made of stainless steel is mounted. Part of the mesh 4 is also in contact with the outer peripheral portion of the end face of the catalyst carrier 2.

The outer diameter of the holding member 3 mounted on the catalyst carrier 2 is larger than the inner diameter of the fixing portion 11, and the catalyst carrier 2 is press-fitted and fixed to the inner periphery of the fixing portion 11 via the holding member 3. I have. Both ends of the catalyst carrier 2 are in press contact with the bent portion 13 via the mesh 4. Thereby, the catalyst carrier 2
Of the holding cylinder 1 in the axial direction is prevented. In addition, since the mesh 4 has some elasticity, stress is prevented from being concentrated on the outer peripheral end of the catalyst carrier 2.

FIG. 2 shows a second example of a catalytic converter to be manufactured by the manufacturing method of the present invention. In this catalytic converter B, a holding cylinder 1 is composed of a main part 1A and a sub part 1B. It is configured. The main part 1A has a fixed part 11, a bent part 13 and a diffuser part 12 following one end thereof. The sub part 1 </ b> B has a diffuser part 12 and a bent part 13. The bent portion 13 of the sub portion 1B is provided on the outer periphery of the other end of the fixed portion 11 of the main portion 1A.
Are fitted and fixed by welding or other fixing means. Other configurations are the same as those of the catalytic converter A.

FIG. 3 shows a third example of a catalytic converter to be manufactured by the manufacturing method of the present invention. In this catalytic converter C, a holding cylinder 1 has a central portion 1C and two end portions. 1D and 1E. The central portion 1C is entirely a fixing portion 11. One end 1 </ b> D has one diffuser part 12 and a bent part 13. The other end 1 </ b> E has the other diffuser portion 12 and the bent portion 13. At the outer periphery of both ends of the central portion 1C, the bent portions 1 of the ends 1D and 1E
3 and 13 are respectively fitted and fixed by fixing means such as welding. Other configurations are the same as those of the catalytic converter A.

Next, the catalytic converters A, B,
A method for manufacturing C will be described. When manufacturing the catalytic converter A, first, as shown in FIG. 4, the outer diameter of the holding member 3 mounted on the outer periphery of the catalyst carrier 2 is measured. In this case, when the pressure equivalent to the pressure applied to the holding member 3 (hereinafter referred to as holding pressure) when the catalyst carrier 2 is pressed into the holding cylinder 1 is applied to the holding member 3, the outer diameter of the holding member 3 is reduced. It is desirable to measure. If the thickness when the holding pressure is applied to the holding material 3 is known, instead of measuring the outer diameter of the holding material 3 attached to the catalyst carrier 2, as shown in FIG. May be measured. This is because the outer diameter of the holding member 3 can be determined by adding twice the thickness of the holding member 3 when the holding pressure is applied to the measured value.

Next, a material for the holding cylinder 1 into which the catalyst carrier 2 on which the holding material 3 and the mesh 4 are mounted is to be press-fitted is prepared. As a material of the holding cylinder 1, a material having an inner diameter that can apply an appropriate pressure to the catalyst carrier 2 after press-fitting is used. This can be achieved by preparing a large number of materials having different inner diameters in advance and selecting one having an appropriate inner diameter from among them. As another method, as shown in FIG. 6, a material 1 'having an inner diameter smaller than the holding cylinder 1 is expanded by bulging or the like,
The material 1 'having an appropriate inner diameter can be obtained. It should be noted that one end of the raw material 1 ′ is attached to the catalyst carrier 2 from the one end.
In order to easily press-fit the material 1 'into the material 1', it is desirable to form a diameter-enlarging portion 14 whose diameter increases from the center to the end. The enlarged diameter portion 14 can be formed by flaring or the like.

Next, as shown in FIGS. 7 and 8, the catalyst carrier 2 on which the holding material 3 and the mesh 4 are mounted is press-fitted from the enlarged diameter portion 14 to the center of the material 1 '. When the catalyst carrier 2 is press-fitted, it is desirable to measure the press-fitting load, and to make the product only when the press-fitting load is within a normal range. If the press-fit load is smaller than the appropriate value, the contact pressure applied to the holding member 3 is small, and there is a possibility that the exhaust gas introduced into one end of the holding cylinder 1 may scatter the holding member 3. If it is large, the catalyst carrier may be broken by excessive pressure. Instead of measuring the press-fit load, the press-fit speed of the catalyst carrier 2 into the material 1 'may be measured. In that case, it is desirable to press-fit the catalyst carrier 2 by applying a constant force. Of course, when the press-fitting speed is measured, only products whose press-fitting speed is within the normal range are regarded as products.

Next, as shown in FIG. 9, a diffuser portion 12 and a bent portion 13 are formed at both ends of the material 1 '.
The diffuser portion 12 and the bent portion 13 can be formed by, for example, a spatula drawing method. By forming the diffuser portion 12 and the bent portion 13, the material 1 'is used as the holding cylinder 1, and the catalytic converter A is manufactured.

As described above, in the present invention, since the catalyst carrier 2 is press-fitted into the holding cylinder 1, the holding cylinder 1 does not vibrate during the press-fitting. Therefore, an excessive pressure does not act on a part of the catalyst carrier 2 when the catalyst carrier 2 is press-fitted. Moreover, since the outer diameter of the catalyst carrier 2 or the outer diameter of the holding material is measured before press-fitting and the catalyst carrier 2 is press-fitted into the holding cylinder 1 having an inner diameter suitable for the measurement, an excessive pressure acts on the catalyst carrier 2. Can be prevented beforehand. Therefore, it is possible to prevent the catalyst carrier 2 from breaking. In particular, by measuring the press-fit load or press-fit speed when press-fitting the catalyst carrier 2 into the holding cylinder 1, it is possible to more reliably prevent the catalyst carrier 2 from breaking.

When the catalytic converter B shown in FIG. 2 is manufactured, the catalyst carrier 2 on which the holding material 3 and the mesh 4 are mounted is pressed into the material of the main portion 1A, and then the diffuser portion 12 and the Forming the bent portion 13 to form the main portion 1
A, and the sub-portion 1B may be fitted and fixed to the main portion 1A.

When the catalytic converter C shown in FIG. 3 is manufactured, the holding member 3 and the mesh 4
After press-fitting the catalyst carrier 2 on which is mounted, the ends 1D and 1E may be fitted and fixed to both ends of the central portion 1C.

[0017]

As described above, according to the present invention, the catalyst carrier can be prevented from being displaced or cracked during the production of the catalytic converter, and the catalyst carrier can be easily pressed into the holding cylinder. The effect that it can be obtained is obtained.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view showing a first example of a catalytic converter manufactured by a manufacturing method of the present invention.

FIG. 2 is a sectional view showing a second example of the catalytic converter manufactured by the manufacturing method of the present invention.

FIG. 3 is a sectional view showing a third example of the catalytic converter manufactured by the manufacturing method of the present invention.

FIG. 4 is a cross-sectional view showing a step of measuring the outer diameter of the holding member in the manufacturing method of the present invention.

FIG. 5 is a diagram showing an outer diameter measuring step of the catalyst carrier in the production method of the present invention.

FIG. 6 is a diagram showing a step of expanding the material of the holding cylinder in the manufacturing method of the present invention.

FIG. 7 is a diagram showing a state before press-fitting the catalyst carrier into the material of the holding cylinder in the manufacturing method of the present invention.

FIG. 8 is a cross-sectional view showing a state after press-fitting the catalyst carrier into the material of the holding cylinder in the manufacturing method of the present invention.

FIG. 9 is a view showing a catalytic converter completed by forming a diffuser portion and a bent portion at both ends of a material into which a catalyst carrier is press-fitted.

[Explanation of symbols]

 Reference Signs List A Catalytic converter B Catalytic converter C Catalytic converter 1 Holding tube 2 Catalyst carrier 3 Holding material 4 Mesh 11 Fixing part 12 Diffuser part

Claims (1)

[Claims] When the catalyst carrier is press-fitted into the holding cylinder, an enlarged portion is formed in advance at the end of the holding cylinder into which the catalyst carrier is inserted, the diameter increasing from the center toward the end. Of catalytic converters characterized by keeping