JP2001355437A - Catalyst holding structure - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide catalyst holding structure facilitating the assembly of a catalyst with a small number of part items. SOLUTION: In this structure of holding the catalyst 2 in a catalyst case 1 through a catalyst holding material 3, a spacer 4 is interposed between the catalyst holding material 3 and the inner periphery of the catalyst case 1. The spacer 4 is constituted to be enlargeable in diameter to come in close contact with the inner peripheral surface of the catalyst case 1 due to the elasticity of the catalyst holding material 3. The spacer 4 is provided on the upstream end side with a flange part 4b for covering the upstream end of the catalyst holding material 3, and on the downstream end side with a claw part 4c capable of axially fixing the catalyst 2 and the catalyst holding material 3 being bent along the tapered face of a downstream funnel part 1a in the catalyst case 1.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a catalyst holding structure for holding and fixing a catalyst in a catalyst case.

[0002]

2. Description of the Related Art FIG. 7 shows a conventional catalyst holding structure, in which a catalyst 2 is held in a catalyst case 1 with a catalyst holding material 3 interposed therebetween. The flange portion 5c of the exhaust manifold 5 is in contact with the flange portion 1c formed on the side, and is connected by bolts 54. The catalyst 2 purifies the exhaust gas, and is formed by coating a ceramic or metal honeycomb-shaped carrier with a noble metal such as platinum, rhodium, or palladium, thereby increasing the catalyst conversion efficiency for the exhaust gas. For this reason, the walls between each cell are very thin honeycomb-shaped, and when a gap is formed between the cells and the catalyst case 1, the wall collides with the inner wall of the catalyst case 1 due to vibration during engine operation or the like. In order to fill the gap, the gap is protected by a catalyst holding member 3 made of a metal mesh or glass fiber, and the catalyst 2 is used for exhaust gas emission during engine operation. Since the catalyst is pushed downstream by pressure, the catalyst case 1 is provided with a stopper step 1d so that the catalyst 2 does not move to the downstream side. Metallic bottom cap 52 for the purpose of lowering the surface pressure is provided to, when further pressure of the exhaust gas is large, the bottom cap 5
An elastic cushioning material 53 may be mounted between the downstream end of the catalyst holding material 2 and the catalyst holding material 3. Further, an upper cap 51 is provided on the upstream side in order to prevent the catalyst holding member 3 from being degraded due to heat or corrosion due to direct impact of the exhaust gas, and FIG. 8 is an exploded perspective view of the constituent members. Show.

[0003] The conventional structure has a problem that the number of components is large and the assembly is complicated. Further, when the catalyst case 1 and the exhaust manifold 5 are joined by friction welding, the catalyst case 1 and the exhaust manifold 5 are connected to each other. There is a problem that the upper cap 51 rotates together with the exhaust manifold 5 in order to provide a continuous relative rotational movement, thereby damaging the catalyst 2 and the catalyst holding material 3.

In order to solve such a problem, as shown in FIG. 9, a funnel 1a having a tapered surface is formed downstream of the catalyst case 1, and the bottom cap 52 is not used. There is a configuration in which the downstream end of the catalyst holding material 3 is wrapped around the funnel 1a to prevent displacement and breakage. When the upper cap 51 is not used as shown in FIG. 9, since the exhaust gas hits the catalyst holding material 3 and generates heat, the catalyst holding material 3 has a high corrosion resistance and a high temperature heat-resistant material. Must be used,
Further, in order to keep the temperature of the exhaust gas on the upstream side of the catalyst 2 low, it is necessary to increase the length of the branch of the exhaust manifold 5 or to provide a radiation fin in the exhaust manifold 5. However, there is a problem that the shape becomes poor in mounting on a car or the like.

[0005]

SUMMARY OF THE INVENTION The present invention has been made in view of the above-mentioned conventional problems, and has as its object to reduce the number of components and facilitate assembly, and to form the catalyst holding member from an inexpensive material. It is an object of the present invention to provide a catalyst holding structure capable of supporting a catalyst in a structure in which a catalyst is held in a catalyst case via a catalyst holding material, wherein a spacer is provided between an outer periphery of the catalyst holding material and an inner periphery of the catalyst case. The spacer has an overlapping portion whose diameter can be expanded so as to be in close contact with the inner peripheral surface of the catalyst case by the elasticity of the catalyst holding material, and the upstream end of the catalyst holding material is provided on the upstream end side. A claw portion that has a flange portion for covering and that can be bent along the tapered surface of a funnel portion formed on the downstream side in the catalyst case at the downstream end side to fix the catalyst and the catalyst holding material in the axial direction. Is provided It is that you are.

[0006]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a sectional configuration view showing a catalyst holding structure, and FIG. 2 is an exploded perspective view of main components.

A funnel 1a having a tapered surface is formed on the downstream side in the catalyst case 1, and an exhaust manifold 5 is joined to the upstream end of the catalyst case 1 by friction welding. A catalyst 2 is inserted into the catalyst case 1, and a catalyst holding material 3 is wound and held around the outer periphery of the catalyst 2. The catalyst holding material 3 of this example has corrosion resistance and high temperature heat resistance. Instead of using a material having excellent elasticity, it is made of an inexpensive material with elasticity.

A spacer 4 is interposed on the outer periphery of the catalyst holding member 3, and the spacer is formed in a cylindrical shape. However, the spacer is divided by an overlapping portion, and the overlapping margin of the overlapping portion 4a is adjusted. Thereby, the inner diameter can be freely reduced or increased.

A flange 4b is integrally formed at the upstream end of the spacer 4 by being horizontally bent inward. The flange 4b covers the upper surface of the upstream end of the catalyst holding member 3 and exhausts the exhaust gas. The gas is provided to prevent the gas from directly hitting the catalyst holding member 3.

At the downstream end of the spacer 4, a plurality of claws 4c, 4c projecting downstream are formed at predetermined intervals in the circumferential direction. The claws 4c are, as shown in FIG. It can be bent at the time of insertion along the tapered shape of the funnel portion 1a in the case 1 and bends, so that the catalyst 2 and the catalyst holding material 3 can be prevented from moving in the axial direction and a good fixed state can be obtained. It has become. This spacer 4
May be used alone, or two or more may be used.

As shown in the exploded view of FIG.
When the catalyst 2 is pressed into the inside using the press-in jig 6, the catalyst holding material 3 is wound around the outer periphery of the catalyst 2, and the spacer 4 is wound around the outer periphery of the catalyst holding member 3, and is pressed into the catalyst case 1. Things. Note that the outer diameter D4 of the press-fitting jig 6 is larger than the inner diameter D1 of the flange portion 4b of the spacer 4, and
When the press-fitting jig 6 is press-fitted, the claw portion 4c of the spacer 4 is bent along the tapered surface of the funnel portion 1a, so that the downstream end of the catalyst holding material 3 is also formed. The catalyst 2 can be bent and wrapped around the downstream end side of the catalyst 2 so as to be held well, and the movement of the catalyst 2 and the catalyst holding material 3 in the axial direction is stopped to be fixed well. Further, the catalyst holding material 3 is compressed in the press-fit state, and the spacer 4 expands in diameter by the elastic force of the catalyst holding material 3, so that the spacer 4 comes into close contact with the inner peripheral surface of the catalyst case 1.

In this embodiment, since the number of parts is small, the assembly to the catalyst case 1 can be easily performed. After the assembly, the exhaust manifold 5 can be joined to the catalyst case 1 by friction welding. In addition, the spacers 4 can be firmly held without rotating together, and can protect the catalyst 2 and the catalyst holding material 3 satisfactorily.

In addition, not only in the case of joining by friction welding, but also in the case of joining by welding as shown in FIG. 4, the catalyst 2 can be fixed and held well by the spacer 4 and the catalyst holding material 3. That is, in FIG. 4, an enlarged diameter joint 1b is formed on the upstream end side of the catalyst case 1, and the lower end of the exhaust manifold 5 is inserted into the enlarged diameter joint 1b to form an outer welding portion. It is joined by welding with P.

In addition, as shown in FIG. 5, a flange 1c is formed at the upstream end of the catalyst case 1 so as to protrude outward.
And the flange portion 5a of the exhaust manifold 5 may be brought into contact with the welding portion P and welded from outside to the welding portion P.
Further, as shown in FIG. 6, a structure in which the catalyst case 1 and the exhaust manifold 5 are butted and welded from the outside and joined at the welded portion P may be used.

[0015]

According to the present invention, in a structure in which a catalyst is held in a catalyst case via a catalyst holding material, a spacer is interposed between an outer periphery of the catalyst holding material and an inner circumference of the catalyst case, and the spacer is a catalyst holding material. It has an overlapping portion that can be expanded in diameter so as to be in close contact with the inner peripheral surface of the catalyst case due to the elasticity of the catalyst case, and has a flange portion on the upstream end side for covering the upstream end of the catalyst holding material, and a downstream end side. Is provided with a claw that can be fixed along the axial direction of the catalyst and the catalyst holding material by being bent along the tapered surface of the funnel formed on the downstream side in the catalyst case. In addition, the catalyst can be easily attached to the catalyst case, and the spacer is tightly attached to the inner peripheral surface of the catalyst case to firmly hold the catalyst via the catalyst holding material. Of the flange portion can be prevented a direct hit of the exhaust gas to the catalyst holding member, therefore the catalyst holding member is intended to be able to use a less expensive material. In addition, the catalyst claw portion of the spacer can firmly fix the catalyst in the catalyst case in a state where the catalyst is prevented from moving in the axial direction, so that the backlash of the catalyst can be completely eliminated.

[Brief description of the drawings]

FIG. 1 is a cross-sectional configuration diagram of a catalyst held in a catalyst case.

FIG. 2 is an exploded perspective view of a constituent member.

FIG. 3 is an exploded view showing an operation of inserting the catalyst into a catalyst case.

FIG. 4 is a sectional configuration view of a structure in which exhaust manifolds are joined by welding.

FIG. 5 is a cross-sectional view of a principal part of still another welding structure.

FIG. 6 is a sectional view of a principal part of still another welding structure.

FIG. 7 is a cross-sectional configuration diagram showing a conventional catalyst holding structure.

FIG. 8 is an exploded perspective view of a conventional constituent member.

FIG. 9 is a cross-sectional configuration diagram of a catalyst holding structure showing another conventional example.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Catalyst case 1a Funnel part 1b Enlarged diameter joint part 1c Flange part 2 Catalyst 3 Catalyst holding material 4 Spacer 4a Overlapping part 4b Flange part 4c Claw part 5 Exhaust manifold 6 Press fitting jig

Claims (1)

[Claims] In a structure in which a catalyst is held in a catalyst case via a catalyst holding material, a spacer is interposed between an outer circumference of the catalyst holding material and an inner circumference of the catalyst case, and the spacer is formed of a catalyst holding material. Along with an overlapping portion capable of expanding in diameter so as to be in close contact with the inner peripheral surface of the catalyst case due to elasticity, on the upstream end side, there is a flange portion that covers the upstream end of the catalyst holding material, and on the downstream end side Is provided with a claw capable of fixing the catalyst and the catalyst holding material in the axial direction by being bent along a tapered surface of a funnel formed on the downstream side in the catalyst case. Construction.