JPS6359015B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an exhaust gas purification device. More specifically, the present invention relates to an exhaust gas purification device using a catalytic converter provided in the exhaust gas path of an internal combustion engine.

Various proposals have been made to prevent air pollution caused by exhaust gas from internal combustion engines, and one of the representative ones is to provide an exhaust gas purification device using a catalytic converter in the exhaust pipe. Since the catalyst carrier used in such exhaust gas purification devices is exposed to the high temperature of the exhaust gas, ceramic is generally used to withstand the high temperature. However, this ceramic is susceptible to thermal shock, so it tends to break when exposed to vibrations from an internal combustion engine in high-temperature exhaust gas. Therefore, in an exhaust gas purification device using such a catalyst carrier, the catalyst carrier is supported by a heat-resistant cushion material, thereby mitigating the effects of vibrations of the internal combustion engine. .

FIG. 8 is a longitudinal sectional view showing a conventional exhaust gas purification device using a catalytic converter. This device has a ceramic catalyst carrier 8 inside a cylindrical container 81.
This catalyst carrier 82 is placed at a certain distance from the inner wall surface of the container 81 by a supporter 83. Further, as described above, the heat-resistant cushion material 84 presses the outer periphery of the catalyst carrier 82 on both sides and is fixed by the stopper 85. This heat-resistant cushion material 8
4 has the role of mitigating the influence of vibration on the catalyst carrier 82, and for this reason, a considerable amount of heat-resistant cushion material is used in the section from the outer periphery of the side surface of the catalyst carrier 82 to the area in contact with the inner wall of the container 81. .

However, since the above-mentioned heat-resistant cushion material generally uses knitted mesh springs made of Inconel alloy wire, the unit cost of the material is extremely high, and the more it is used, the more the cost of the exhaust gas purification device increases. The problem is that you have to give up.

The purpose of the present invention is to reduce the amount of expensive heat-resistant cushioning material used, and to reduce the axial holding force of the heat-resistant cushioning material even if the thickness decreases over time due to long-term use, resulting in damage to the catalyst carrier. An object of the present invention is to provide an exhaust gas purification device that reliably maintains the exhaust gas so as not to cause any damage.

The exhaust gas purification device of the present invention which achieves the above object has a catalyst carrier placed in a container having openings on both sides for exhaust gas introduction and exhaust gas discharge, with a certain gap between the container and the inner wall surface of the container. A heat-resistant cushion material having approximately the same outer diameter as the catalyst carrier is provided on the outer peripheral side surfaces of both ends of the catalyst carrier, and this heat-resistant cushion material is held from the outer surface with a retainer. The outer circumferential portion is bent in a stepped manner so as to wrap around the outer circumferential surface of the heat-resistant cushion material, and the inner circumferential portion is left unrestrained with respect to the inner circumferential surface of the heat-resistant cushion material, and the inner diameter of the stepped portion is bent. is characterized in that it is slightly larger than the outer diameter of the catalyst carrier.

Hereinafter, details of the present invention will be explained with reference to embodiments shown in the drawings.

FIG. 1 shows an exhaust gas purification apparatus showing an embodiment of the present invention, in which a catalyst carrier 2 made of ceramic is housed inside a cylindrical container 1. The cylindrical container 1 is composed of two cylindrical bodies 1A and 1B, each of which has a flange-like joint that opens outward at right angles, and the flange portions are in contact with each other. , fixed by welding. Such a divided structure allows the catalyst carrier 2 to be assembled into the container 1 after being separated into two cylinders 1A and 1B, which facilitates the installation of the catalyst carrier 2 and improves productivity. It is useful for increasing

The catalyst carrier 2 is supported inside the container 1 via the supporter 3, so that a certain distance is maintained between the outer circumference of the catalyst carrier 2 and the inner peripheral wall surface of the container 1. It turns out. A heat-resistant cushion material 4 held by a retainer 6 is in contact with the outer peripheral side of both sides of the catalyst carrier 2, and a stopper 5 is applied from the outside so as to press it toward the catalyst carrier 2 side. , this stopper 5
The whole is fixed by welding between the and container 1. Here, the ring-shaped heat-resistant cushion material 4 has an outer diameter that is substantially the same as the outer diameter of the catalyst carrier 2, and does not extend to the inner peripheral wall surface of the container 1 as in conventional devices. . On the other hand, the retainer 6 holds the heat-resistant cushion material 4 on the side (outer side) opposite to the side (inner side) facing the catalyst carrier 2. Moreover, this retainer 6
is bent in a stepped manner so that its outer circumferential portion wraps around the outer circumferential surface of the heat-resistant cushion material 4, and is further extended toward the inner circumferential wall surface of the container 1 so as to come into contact with the inner circumferential wall surface. On the other hand, retainer 6
The inner circumference of the heat-resistant cushion material 4 is punched out to have a diameter substantially the same as or slightly smaller than the inner diameter of the heat-resistant cushion material 4, so that the inner circumferential surface of the heat-resistant cushion material 4 is not constrained. Further, the inner diameter of the stepped portion of the retainer is slightly larger than the outer diameter of the catalyst carrier 2.

By holding with the retainer 6 as described above,
The heat-resistant cushion material 4 having a small outer diameter is securely fixed and is adapted to reduce the influence of external vibrations on the catalyst carrier 2. In addition, the heat-resistant cushion material 4 is made smaller in diameter to reduce the amount of material used, and its thickness gradually decreases with long-term use, so the axial holding force against the catalyst carrier 2 generally weakens. It turns out. However, in this invention, the inner diameter of the stepped portion of the retainer 6 wraps around the outer circumferential surface of the heat-resistant cushion material 4, and the inner circumferential surface is left in an unrestricted state. When 4 thermally expands, the expansion in the outer radial direction is suppressed, and as a result, it is made to expand significantly in the thickness direction (axial direction). Therefore, the axial holding force for the catalyst carrier 2 described above is not reduced, and the catalyst carrier 2 can be held reliably for a long period of time.

In addition, since the inner diameter of the stepped portion of the retainer 6 is slightly larger than the outer diameter of the catalyst carrier 2, the fragile catalyst carrier 2 may move in the axial direction due to a decrease in holding force. Even if something happens, the retainer 6 will not be touched and damage to it can be prevented.

The exhaust gas purification device configured as described above is fixed in the exhaust pipe 7. This installation position may be part of the silencer. In such an exhaust pipe 7 or silencer, exhaust gas is introduced as shown by the arrow in FIG. 1, purified by the catalyst in the catalyst carrier 2, and then discharged to the exhaust side as shown by the arrow.

FIG. 2 is a sectional view showing a part of an exhaust gas purification device according to another embodiment of the present invention. In this embodiment, the shape of the outer circumferential end of the retainer 6 is not perpendicular to the inner circumferential wall surface of the container 1 as in the embodiment shown in FIG. 1, but is made to abut at an angle. By this,
Processing of the retainer 6 is facilitated.

In the embodiment shown in FIG. 3, the retainer 6' is integrated so as to hold the heat-resistant cushion material 4 and also serve as the stopper 5 in each of the embodiments shown in FIGS. 1 and 2. It is.

In the embodiments shown in FIGS. 4 and 5, the inner circumferential edge of the retainer 6 is inclined toward the catalyst carrier 2, respectively. By adopting such a retainer shape, the ring-shaped heat-resistant cushion material 4 is strongly pressed against the catalyst carrier 2 at its inner peripheral end, so that the outer peripheral end of the catalyst carrier 2 is prevented from being damaged by vibration. It is also possible to prevent exhaust gas from leaking into the gap between the catalyst carrier 2 and the container 1.

The embodiment shown in FIG. 6 is a modification of the embodiment shown in FIG. 4 or FIG. 5 described above, in which a retainer 6' is integrated so as to also serve as a stopper.

In the case of each of the embodiments shown in FIGS. 2 to 6 described above,
As in the embodiment shown in FIG. 1, since the outer diameter of the heat-resistant cushion material 4 is made substantially the same as that of the catalyst carrier 2, the amount of cushion material can be saved. In addition, since the retainer 6 wraps the outer peripheral surface of the heat-resistant cushion material 4 with its stepped inner diameter portion and leaves the inner peripheral surface unrestricted, thermal expansion in the outer diameter direction is smoothly extended in the thickness direction. Maintains reliable axial holding force to compensate for the reduction in stiffness. Furthermore, since the inner diameter of the stepped portion of the retainer 6 is made slightly larger than the outer diameter of the catalyst carrier 2, even if the catalyst carrier 2 moves in the axial direction due to insufficient holding force, the retainer No damage will be caused by contact with.

As described above, in the exhaust gas purification device of the present invention, since the outer diameter of the heat-resistant cushion material is made substantially the same as that of the catalyst carrier, the amount of expensive heat-resistant cushion material used can be reduced. Moreover,
Even if the heat-resistant cushion material becomes thin due to long-term use, the stepped portion of the retainer wraps around the outer circumferential surface of the heat-resistant cushion material and leaves the inner circumferential surface unrestricted. By suppressing thermal expansion in the radial direction and promoting smooth elongation in the axial direction (thickness direction), it is possible to compensate for a decrease in axial holding force due to thinning.

In addition, since the inner diameter of the stepped portion of the retainer is slightly larger than the outer diameter of the catalyst carrier, in the unlikely event that the axial holding force of the heat-resistant cushion material decreases and the fragile catalyst carrier moves. It is also possible to prevent the catalyst carrier from being damaged.

[Brief explanation of the drawing]

FIG. 1 is a longitudinal cross-sectional view of an exhaust gas purification device according to an embodiment of the present invention, FIGS. 2 to 6 are longitudinal cross-sectional views showing parts of the device according to other embodiments of the present invention, and FIG. is a longitudinal cross-sectional view of a conventional device. DESCRIPTION OF SYMBOLS 1... Container, 2... Catalyst carrier, 3... Supporter, 4... Heat resistant cushion material, 5... Stopper, 6, 6'... Retainer.

Claims (1)

[Claims] 1. A catalyst carrier is housed in a container with openings for exhaust gas introduction and exhaust gas discharge on both sides, with a certain gap between the inner wall surface of the container, and the outer peripheral side surfaces of both ends of the catalyst carrier are A heat-resistant cushion material having an outer diameter approximately the same as that of the catalyst carrier is provided on each of the catalyst carriers, the heat-resistant cushion material is held from the outer surface by a retainer, and the outer circumferential portion of the retainer is wrapped around the outer circumferential surface of the heat-resistant cushion material. The catalyst carrier is bent in a stepped shape, and the inner circumferential portion is not constrained with respect to the inner circumferential surface of the heat-resistant cushion material, and the inner diameter of the stepped portion is slightly larger than the outer diameter of the catalyst carrier. An exhaust gas purification device featuring: