JP3304871B2 - Catalytic converter - Google Patents

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 object, the present invention provides a method for mounting a catalyst in a central portion of a catalyst holding cylinder.
Then, the catalyst holding cylinders at the center in the front and rear directions in the axial direction are reduced in diameter and
A fuser and protection on the outer periphery of the catalyst holding cylinder
Provide a cylinder and reduce the diameter by spinning the front and rear of the protection cylinder
And a cone-shaped portion corresponding to the diffuser
It is characterized by. Or, therein the catalytic holding cylinder central portion of the catalyst retaining section, the catalyst was placed intumescent mat or holding material steel net etc. attached to the outer periphery, axially before and after the catalyst retention of the catalyst retaining section with the diffuser cylinder with reduced diameter, the the outer periphery of the catalyst holding tube provided protection tube, reduced in diameter before and after the protective tube and a cone-shaped portion corresponding to the diffuser, one of the catalyst holding tube The diffuser and the cone-shaped portion of the protection tube corresponding to the diffuser are fixed to the flange, and the catalyst holding tube and the protection tube are interposed between the other diffuser and the cone-shaped portion corresponding to the diffuser via an elastic material such as a spring. And a flange is fixed to either the other diffuser or the cone-shaped portion.

[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-shaped 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. The catalyst holding tube and the protection tube have a double structure, so that the heat insulation and soundproofing effects 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.

[Description of Signs] 1 catalyst holding tube 2 catalyst holding portion 3 thermal expansion mat 4,5 catalyst 6,7 diffuser 8 protection tube 9,10 cone-shaped portion 11,12 flange

──────────────────────────────────────────────────続 き Continuation of the front page (56) References JP-A-9-112259 (JP, A) JP-A-6-101465 (JP, A) JP-A 8-170526 (JP, A) JP-A 8- 200050 (JP, A) JP-A-9-242533 (JP, A) JP-A-8-303236 (JP, A) JP-A-61-110823 (JP, U) JP-A-2-124215 (JP, U) Japanese Utility Model Application Hei 5-96427 (JP, U) Japanese Utility Model Application Hei 2-19820 (JP, U) (58) Fields investigated (Int. Cl. ⁷ , DB name) F01N 3/28

Claims (2)

(57) [Claims] [Claim 1] A catalyzes the center of the catalytic holding cylinder is mounted,
With the diffuser decreases in diameter catalyst holding tube in the longitudinal axial direction of the central portion, said protection tube provided on the outer periphery of the catalyst holding tube, with the diffuser before and after the protective tube is reduced in diameter by a spinning process A catalytic converter characterized by a corresponding cone-shaped portion. 2. A catalyst holding portion having a central portion of the catalyst holding tube as a catalyst holding portion.
Inside, a heat-expandable mat or steel net
The catalyst holding section is provided with a holding material such as
The diameter of the catalyst holding cylinders before and after the
And a protection cylinder is provided on the outer periphery of the catalyst holding cylinder,
Reduce the diameter of the front and rear of the protective cylinder to fit the diffuser
And one diffuser of the catalyst holding cylinder and the diffuser.
Flange the cone-shaped part of the protective cylinder corresponding to the diffuser
To the other diffuser and the corresponding diffuser
Through an elastic material such as a spring between the
Holding the catalyst holding tube and the protection tube, and using the other diffuser
The flange is fixed to either the user or the cone
A catalytic converter characterized by the following.