JPS6345533Y2 - - Google Patents

Description

[Detailed description of the invention] (Field of industrial application) The present invention is a catalytic converter with a double-shell container structure in which a sound insulating material is filled between an inner shell that supports a catalyst carrier and an outer shell provided outside of the inner shell. This is related to the improvement of.

(Prior art) Conventionally, as a catalytic converter used in engine exhaust gas purification devices, for example,
As disclosed in Publication No. 53-115212, etc., an inner shell supporting a catalyst carrier and an outer shell provided outside the inner shell are each divided into two in the vertical direction, and a sound insulating material such as glass wool is placed between the two shells. A double shell container structure in which an inner shell and an outer shell are filled and then integrally joined by hemming at their peripheral edges is well known.

By the way, in such a catalytic converter with a double-shell container structure, in order to protect the edge part of the catalyst carrier from hitting the inner shell and being damaged due to external vibration, a part of the axially intermediate part of the inner shell is inserted inside the inner shell. By forming a concave portion that is concave in the opposite direction and supporting the intermediate portion of the catalyst carrier by the concave portion, a relief space is provided between the edge portion of the catalyst carrier and the inner shell, while the concave portion is provided in the outer shell. By forming a protrusion that protrudes inward so as to leave a predetermined space between the two, and using the protrusion to process the recess with a predetermined pressure through the sound insulating material in the same way as other parts. A structure is adopted that suppresses the generation of radiant noise from the catalytic converter due to membrane vibration of the inner shell due to pressure fluctuations (pulsations) of exhaust gas flowing into the inner shell.

However, in this case, since the accuracy of the thickness dimension of the sound insulating material is rough, the protruding part of the outer shell interferes with the sound insulating material near the opening edge of the recessed part of the inner shell, making it difficult to fit well into the recessed part, and the protruding part The pressure applied to the concave portion by the catalytic converter may be zero or insufficient, and as a result, there has been a problem that the effect of reducing radiated sound caused by membrane vibration of the inner shell of the catalytic converter varies.

(Purpose of the invention) In view of the above, the present invention improves the distribution of the sound insulation material filled between the inner shell and the outer shell of the catalytic converter, thereby eliminating the influence of the dimensional accuracy of the sound insulation material. , by eliminating interference between the sound insulating material at the opening edge of the recess of the inner shell and the protruding part of the outer shell, and ensuring that the recess is pressurized by the protruding part through the sound insulating material. The purpose is to achieve an effective radiated sound reduction effect.

(Structure of the invention) In order to achieve the above object, the structure of the invention is as follows:
As described above, a sound insulating material is filled between the inner shell for supporting the catalyst carrier and the outer shell outside thereof, and a recess is formed in the inner shell, and a protrusion is formed in the outer shell so as to have a predetermined space between the inner shell and the recess. In the catalytic converter, a sound insulating material is interposed in the space between the bottom surface of the recess and the protrusion, but no sound insulating material is interposed between the vicinity of the opening edge of the recess and the outer shell. It is composed of That is, the sound insulating material near the opening edge of the recess is removed to eliminate interference between the sound insulating material and the protrusion.

(Effect of the invention) Therefore, according to the invention, since a space is formed between the vicinity of the opening edge of the recess of the inner shell and the outer shell without sound insulation material, the dimensional accuracy of the sound insulation material varies. By eliminating interference between the sound insulating material near the opening edge of the recess and the tip edge of the outer shell protrusion, the recess can be appropriately pressurized by the protrusion, and the inner shell membrane It is possible to reliably reduce vibration and fully exhibit the effect of reducing the radiated noise of the catalytic converter.

(Example) Hereinafter, embodiments of the present invention will be described in detail.

1 and 2 show a catalytic converter according to an embodiment of the present invention, in which 1 is a cylindrical casing, and the casing 1 is divided into upper and lower parts in the axial direction, and includes a monolithic catalyst carrier 11 to be described later. , 12 formed by a pair of press-formed inner shells 2, 2, and a pair of press-formed inner shells 2, 2 arranged at a predetermined gap on the outside of the inner shells 2, 2 and also divided into upper and lower parts in the axial direction. The outer shells 3, 3 are bonded to each other at the flange portions 2a, 3a formed on the outer periphery of each shell 2, 3 to be integrated, and the gap between the inner shells 2, 2 and the outer shells 3, 3 is is filled with a sound insulating material 4 made of glass wool or the like.

The central part of the casing 1 has a catalyst storage part 1a that is flat in the vertical direction and has an elliptical cross section, and the front and rear ends of the catalyst storage part 1a have exhaust pipe connection parts on the inlet side and the outlet side that have circular cross sections. 1b,1
c, and an exhaust pipe connection inlet flange 6 having an exhaust gas inlet 6a at the center is fixed to the front end of the inlet side exhaust pipe connection part 1b via the inner case 5 by welding, and An exhaust pipe connecting outlet flange 8 having an exhaust gas outlet 8a in the center is fixed to the rear end of the outlet side exhaust pipe connecting portion 1c via a reinforcing ring 7 by welding, and both flanges 6, 8 Stud bolts 9 and 10 for connecting exhaust pipes are installed in each of the holes.

In the catalyst storage portion 1a of the casing 1, a reduction monolith catalyst carrier 11 is arranged in the upstream stage, and an oxidation monolith catalyst carrier 12 is arranged in series in the downstream stage in the axial direction of the casing 1. A spacer 13 is interposed between the monolithic catalyst carriers 11 and 12, and a predetermined distance S serving as a mixing area is maintained between the monolithic catalyst carriers 11 and 12 by the spacer 13.
Both of the monolithic catalyst carriers 11 and 12 are made of a ceramic material having a large number of ventilation holes passing through them in the axial direction in a honeycomb shape, and are coated with a catalyst such as platinum.

The spacer 13 has support flange portions 14a and 15a having an L-shaped cross section and projecting outward from the outer peripheral edge of the tip.
It is formed by bonding together two substantially symmetrical elliptical dish-shaped press-molded members 14 and 15 having
Support flange portion 1 of the press-formed members 14, 15
The outer circumferential surfaces of the inner shells 4a, 15a are brought into contact with the inner circumferential surfaces of the inner shells 2, 2 and fixed by, for example, plug welding. Further, a support flange portion 5a is formed at the rear end of the inner case 5 and is expanded so as to come into contact with the inner surfaces of the inner shells 2, 2, and a support flange portion 5a is formed at the rear end of the catalyst storage portion 1a of the casing 1. That is, a support flange portion 1d formed by drawing the inner shells 2, 2 inward in a step-like manner is formed at the boundary with the outlet-side exhaust pipe connection portion 1c. Then, the monolithic catalyst carrier for reduction 11
The front end surface in the axial direction is pressed and held by the support flange portion 5a of the inner case 5, and the rear end surface in the axial direction is attached to the support flange portion 14a of the front press-formed member 14 of the spacer 13 with a ring-shaped elastic material such as steel mesh. The upstream portion of the catalyst storage portion 1a of the casing 1 is elastically held through the body 16, and the outer peripheral surface is elastically held on the inner surfaces of the inner shells 2, 2 via a cylindrical elastic body 17 such as steel wool. It is fitted in the front section of the side. Similarly, the oxidation monolith catalyst carrier 12 has a front end surface in the axial direction facing the rear press-formed member 15 of the spacer 13.
The rear end surface in the axial direction is pressed against the support flange portion 15a of the casing 1, and the rear end surface in the axial direction is held by the support flange portion 1d of the casing 1.
is elastically held through a ring-shaped elastic body 18 such as a steel mesh, and further elastically held on the outer circumferential surface through a cylindrical elastic body 19 such as steel wool. It is fitted at the rear.

Further, the bottom bonding surfaces of the press-formed members 14 and 15 constituting the spacer 13 are perforated leaving the bonding flange portions 14b and 15b on the outer periphery to form a communication opening 20, and A screen-shaped buttful 21 extends vertically inward in the radial direction by the mating flange portions 14b and 15b.
is formed.

Further, 22 indicates both the monolithic catalyst carriers 11 and 1.
The secondary air supply nozzle 22 is a secondary air supply nozzle disposed so as to cross the longitudinal center part of the interval S between the two in the longitudinal direction of the ellipse. By passing the outer shell 3 through the support hole 23 formed between the press-formed members 14 and 15 of the spacer 13, the support hole 23 supports the outer shell 3 in a relaxed state, and both the shells 2, 3
It is fixed by welding at the penetrating part.
The tip of the secondary air supply nozzle 22 is closed, and the rear end is connected to the casing 1.
It is led out and connected to an air pump (not shown) via a connecting flange 24, thereby forming a secondary air supply passage 25. Further, a large number of secondary air injection holes 22a, 22a, . (Secondary air supply nozzle 22) is configured to eject and supply the secondary air rearward from the secondary air injection holes 22a, 22a, . . . within the interval S.

Further, in the inner shells 2, 2, in the case of the upper inner shell 2, the lower inner shell Similarly, in the case of No. 2, a catalyst carrier supporting portion is recessed inwardly by a predetermined dimension at a portion substantially directly below the monolithic catalyst carriers 11 and 12 and corresponding to approximately the center in the longitudinal direction of both monolithic catalyst supports 11 and 12. recess 26,
26,... are formed.

On the other hand, on the inner surfaces of the outer shells 3, 3, projecting inward so as to have a predetermined space between each of the recesses 26, 26, . . . of the inner shells 2, 2, respectively. Pressure plates 27, 27, . . . as protruding portions are integrally attached by welding. As shown in enlarged detail in FIG. 3, the bottom surface 26a of each of the recesses 26,
In the space between the pressure plate 27 (protrusion) corresponding to each recess 26, the sound insulating material 4, which is filled between the inner shells 2, 2 and the outer shells 3, 3, is interposed as described above. Between the vicinity of the opening edges 26a, 26b in the front-rear direction of each of the recesses 26 and the outer shells 3, 3 or pressure plates 27, 27, . . . corresponding to the vicinity of the opening edges 26b, 26b (in FIG. The area (indicated by zone) is configured in a spatial state in which no sound insulating material 4 is interposed.

In addition, 28 is a perforated plate that is attached to the front of the reduction monolithic catalyst carrier 11 in the axial direction and is made of a perforated plate that rectifies the flow of exhaust gas; 29 and 3;
0 is a sealing material interposed between the inner shells 2, 2 and the rear ends of the outer peripheral surfaces of monolithic catalyst carriers 11 and 12 for reduction and oxidation, respectively, and 31 is a pipe for attaching a converter sensor.

Therefore, in the embodiment described above, the exhaust gas flowing into the casing 1 from the exhaust gas inlet 6a of the exhaust pipe connection inlet flange 6 first passes through the baffle plate 28 and then flows into the monolithic catalyst carrier 11 for reduction. The flow is reduced and purified by the catalyst carrier 11, and then, after passing through the monolithic catalyst carrier 11 for reduction, the flow becomes turbulent due to the screen-like baffle 21 of the spacer 13, and the flow is reduced to a distance S as a mixing area. is mixed well with the secondary air supplied from the secondary air supply nozzle 22 in the interval S, and then flows into the oxidation monolithic catalyst carrier 12 and is mixed well with the secondary air supplied from the secondary air supply nozzle 22 at the interval S.
The exhaust gas is oxidized and purified, and then discharged from the exhaust gas outlet 8a of the exhaust pipe connection outlet flange 8.

In this case, a sound insulating material 4 is provided in the space between the bottom surface 26a of each recess 26 for supporting a catalyst carrier provided at a predetermined position of the inner shells 2, 2 and each pressure plate 27 attached to the inner surface of the outer shells 3, 3. Although interposed, the opening edges 26 at the front and rear of each of the recesses 26
The space between the outer shells 3, 3 or each pressure plate 27 corresponding to the vicinity of the opening edges 26b, 26b and the vicinity of the opening edges 26b, 26b is a space in which the sound insulation material 4 is not interposed. Even if there are variations in thickness, the sound insulating material 4 will not interfere with the fitting of each pressure plate 27 into each recess 26, and each pressure plate 27 will not interfere with the fit of each pressure plate 27 in other parts. As in the pressurized state, the bottom surface of each recess 26 is reliably pressurized via the sound insulating material 4. Therefore, due to the pressure fluctuation (pulsation) of the exhaust gas flowing into the inner shells 2, 2 of the casing 1, the inner shells 2, 2 are It is possible to suppress membrane vibration of the catalytic converter, and it is possible to reliably reduce the radiation noise of the catalytic converter.

In the above embodiment, the respective recesses 26 for supporting the catalyst carrier of the inner shells 2, 2 are pressurized by the pressure plates 27 provided separately from the outer shells 3, 3. Each recess 26 of the inner shell 2, 2 in the outer shell 3, 3
This may be achieved by a protruding portion formed by integrally protruding the portion corresponding to the inward direction, and the same effects as in the above embodiment can be achieved.

[Brief explanation of the drawing]

The drawings show an embodiment of the present invention; FIG. 1 is a partially cutaway plan view, FIG. 2 is a sectional view taken along the line -- in FIG. 1, and FIG. 3 is an enlarged sectional view of the main part. 1...Casing, 2...Inner shell, 3...
... Outer shell, 4 ... Sound insulation material, 11 ... Monolithic catalyst carrier for reduction, 12 ... Monolithic catalyst carrier for oxidation, 13 ... Spacer, 22 ... Secondary air supply nozzle, 26 ... Recess, 26a ... Bottom surface , 26b
...Opening edge, 27...Pressure plate.

Claims (1)

[Scope of utility model registration request] In a catalytic converter in which a catalyst carrier is supported by an inner shell, and a sound insulating material is filled between the inner shell and an outer shell provided outside the inner shell, a recessed portion recessed inwardly is formed in the inner shell, and a recessed portion is formed in the outer shell. A protrusion protruding inward is formed to have a predetermined space between it and the recess, and a sound insulating material is interposed in the space between the bottom of the recess and the protrusion, and the opening of the recess is A catalytic converter characterized in that a space is formed with no sound insulating material interposed between the vicinity of the edge and the outer shell.