JPH11270335A - Catalyst converter - Google Patents

Abstract

PROBLEM TO BE SOLVED: To reduce manufacturing costs by eliminating the work of integrating the front and rear diffusers together by welding or other means and to absorb differential thermal expansion as well as to improve heat insulation and sound insulation effect. SOLUTION: Catalysts 4, 5 having a thermal expansion mat 3 arranged on its outer circumference is mounted on the interior of a catalyst holding cylinder 1 having its central part as a catalyst holding part 2 in series and the catalyst holding cylinder 1 axially longitudinal to the catalyst holding part 2 is made diffusers 6, 7 by shrinking the diameter by spinning or the like. A single pretection cylinder 8 is provided on the outer circumference of the catalyst holding cylinder 1 and the front and rear of the protection cylinder 8 is made in cone shape parts 9, 10 corresponding to the diffusers 6, 7 of the catalyst holding cylinder 1 by shrinking its diameter by spinning or the like. One of the diffusers 6 of the catalyst holding part 2 and the cone shape part 9 corresponding to the diffuser 6 are fixed to a flange 11, while the catalyst holding cylinder 1 and the protection cylinder 8 are held between the other diffuser 7 and the cone shape part 10 corresponding to the diffuser 7 through an elastic, material 12 such as a spring and the flange 13 is fixed to the cone shape part 10.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a catalytic converter mounted on a vehicle exhaust system or the like.

[0002]

2. Description of the Related Art A catalytic converter of this kind is disclosed in
It is also known from the disclosure in JP-A-242533. The catalytic converter disclosed in this publication,
A tapered outer cylinder having a diameter gradually reduced from the front part to the rear part, and a ceramic carrier held in the outer cylinder via a thermally expandable mat filled with a press-fitted and filled thermal expansion mat.
An outer shell attached to the front of the outer cylinder, an inner shell mounted coaxially with the ceramic carrier, and a diffuser attached to the rear of the outer cylinder. The inner shell is formed at the rear peripheral edge thereof with an annular flange portion which comes into contact with the front end of the thermally expandable mat and presses the same in the axial direction of the ceramic carrier.

[0003] However, there are actually technical problems described below.

[0004]

That is, in the above-mentioned conventional catalytic converter, a tapered outer cylinder for holding a ceramic carrier, an outer shell and a diffuser which are formed of separate members are integrated. However, it takes a lot of time and effort to manufacture, which causes an increase in cost. In addition, the inner shell part has a double structure together with the outer shell, but the heat-expandable mat part has problems such as insufficient heat insulation and soundproofing because the shell does not have a double structure. there were.

The present invention solves the above-mentioned problems, and can reduce the cost by eliminating the work of integrating the front and rear diffusers by welding or the like, improve the heat insulation and sound insulation effects, and improve the heat insulation. An object of the present invention is to provide a catalytic converter capable of absorbing a difference in expansion.

[0006]

In order to achieve the above-mentioned object, the present invention provides a catalyst holding cylinder having a central portion serving as a catalyst holding portion inside and a heat-expandable mat or steel net or the like on the outer periphery. A catalyst provided with a holding material is mounted, the diameter of the catalyst holding tube in the front and rear direction of the catalyst holding portion is reduced to form a diffuser, and a single protection tube is provided on the outer periphery of the catalyst holding tube. The diameter of the front and rear is reduced to a cone-shaped portion corresponding to the diffuser, one diffuser of the catalyst holding tube and the cone-shaped portion of the protection tube corresponding to the diffuser are fixed to a flange, and the other diffuser and the diffuser are fixed to the other diffuser. That the catalyst holding tube and the protection tube are held between the corresponding cone-shaped portion via an elastic material such as a spring, and that the flange is fixed to either the other diffuser or the cone-shaped portion. And butterflies.

[0007]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Preferred embodiments of the present invention will be described below in detail with reference to the drawings. FIG. 1 is a sectional view of a catalytic converter of the present invention, FIG. 2 is an enlarged view of a portion where a flange is fixed to a cone portion, and FIG. 3 is an enlarged view of a portion where a flange is fixed to a diffuser.

As shown in FIG. 1, a central portion of one catalyst holding tube 1 is used as a catalyst holding portion 2 and a heat-expandable mat 3 (or steel net) as a holding material is provided on the inside thereof. The arranged catalysts 4 and 5 are mounted in series, and the diameters of the catalyst holding cylinders 1 before and after the catalyst holding unit 2 in the axial direction (left and right directions in the drawing) are reduced by spinning or the like to form diffusers 6 and 7.

A single protection cylinder 8 is provided on the outer periphery of the catalyst holding cylinder 1, and the diameter of the front and rear of the protection cylinder 8 is reduced by spinning or the like to form a cone-shaped portion corresponding to the diffusers 6 and 7 of the catalyst holding cylinder 1. 9 and 10. While one diffuser 6 of the catalyst holding part 2 and a cone-shaped part 9 corresponding to the diffuser 6 are fixed to the flange 11, a spring is provided between the other diffuser 7 and the cone-shaped part 10 corresponding to the diffuser 7. The catalyst holding tube 1 and the protection tube 8 are held via an elastic material 12 such as the above, and a flange 13 is fixed to the cone-shaped portion 10.

The flange 13 may be fixed to the diffuser 7 as shown in FIG. FIG. 1 shows a view in which the diffuser 6 and the corresponding cone-shaped portion 9 are fixed to the flange 11, but the diffuser 7 and the cone-shaped portion 10 are not shown.
Is fixed to the flange 13, and an elastic material 12 such as a spring is provided between the diffuser 6 and the corresponding cone-shaped portion 9.
Alternatively, the catalyst holding tube 1 and the protection tube 8 may be held via a, and the flange 11 may be fixed to the cone portion 9. In this case, the flange 11 may be fixed to the diffuser 6.

In the above construction, both the catalyst holding tube 1 and the protection tube 8 are reduced in diameter from the front to the rear to form the diffusers 6, 7 or the cone-shaped portions 9, 10 (the diffusers 6, 7 are (Integrally with the catalyst holding tube 1 and the cone-shaped portions 9 and 10 are integrated with the protection tube 8), fixing work such as welding can be omitted and the cost can be reduced. Has a double structure, so that the effects of heat insulation and soundproofing are improved. Further, since the unpurified exhaust gas is burned and purified by the catalysts 4 and 5, the temperature of the catalyst holding cylinder 1 becomes higher than that of the protection cylinder 8 and the thermal expansion increases. Since it is held free via an elastic material 12 such as a spring, there is an excellent effect that a difference in thermal expansion can be absorbed.

[0012]

According to the above construction, both the catalyst holding tube and the protection tube are reduced in diameter from the front to the back to form a diffuser or a cone, so that a fixing means such as welding can be omitted. As a result, the catalyst holding tube and the protection tube have a double structure, so that the effects of heat insulation and soundproofing are improved. In addition, since the unpurified exhaust gas is burned and purified by the catalyst, the temperature of the catalyst holding tube becomes higher than that of the protection tube and the thermal expansion becomes larger, but one of the catalyst holding tube and the protection tube is provided via an elastic material such as a spring. , So that the difference in thermal expansion can be absorbed.

[Brief description of the drawings]

FIG. 1 is a sectional view of a catalytic converter according to the present invention.

FIG. 2 is an enlarged view of a portion where a flange is fixed to a cone-shaped portion of the catalytic converter.

FIG. 3 is an enlarged view of a portion where a flange is fixed to a diffuser of the catalytic converter.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Catalyst holding cylinder 2 Catalyst holding part 3 Thermal expansion mat 4, 5 Catalyst 6, 7 Diffuser 8 Protection cylinder 9, 10 Conical part 11, 12 Flange

Claims (1)

[Claims] 1. A catalyst having a holding member such as a heat-expandable mat or a steel net disposed on an outer periphery thereof is mounted inside a center portion of one catalyst holding tube as a catalyst holding portion, and a shaft of the catalyst holding portion is provided. Along with reducing the diameter of the catalyst holding tube in the front and rear directions to form a diffuser, providing one protection tube on the outer periphery of the catalyst holding tube, reducing the diameter of the front and rear of the protection tube to form a cone-shaped portion corresponding to the diffuser. The one diffuser of the catalyst holding tube and the cone portion of the protection tube corresponding to the diffuser are fixed to the flange, and an elastic material such as a spring is interposed between the other diffuser and the cone portion corresponding to the diffuser. A catalyst holding tube and a protection tube, and a flange fixed to either the other diffuser or the cone-shaped portion.