JPH07279655A - Ceramic honeycomb catalytic converter - Google Patents

Abstract

PURPOSE:To fix a support to a casing not to cause the disadvantage of losing the retaining force which retains the support according to a difference in thermal expansion and contraction between the ceramic honeycomb catalyst support and the metal casing even if the honeycomb catalyst support is longer. CONSTITUTION:A honeycomb catalyst support 11 is locally fixed at one end thereof to a casing 17 through a buffer, and the other end is not fixed to the casing. To be concrete, a flange part 12 is provided on the outer periphery of one longitudinal end of the honeycomb catalyst support, the flange part is clamped by a vertical stepped part 19 of an end plate 18 of the casing 17 and a metal presser 21 through mesh washers 15, 16 of the buffer, and the metal presser 21 is fixed to the parallel side part 20 of the end plate 18 by welding or the like.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a ceramic honeycomb catalytic converter for purifying exhaust gas and combustion gas from automobiles, and more particularly to a support structure for a honeycomb catalyst carrier.

[0002]

2. Description of the Related Art FIG. 5 is an explanatory view (cross-sectional view) of a typical example of a supporting structure for supporting and fixing a ceramic honeycomb catalyst carrier by a casing in a conventional ceramic honeycomb catalyst converter. Reference numeral 1 is a ceramic honeycomb catalyst carrier in which a catalyst for purifying exhaust gas and combustion gas is carried. 2 is a mesh washer,
The honeycomb catalyst carrier 1 is mounted between the halved metal casing 4 and the honeycomb catalyst carrier 1 so as to surround the entire circumference of the shoulders at both ends in the longitudinal direction. Reference numeral 3 denotes a mesh supporter, which is mounted in the gap between the outer peripheral surface of the honeycomb catalyst carrier 1 and the casing 4. The honeycomb catalyst carrier 1 is held and fixed to the casing via mesh washers at both ends thereof, and the difference in thermal expansion and contraction between the honeycomb catalyst carrier 1 made of ceramic and the casing 4 made of metal is adjusted by the mesh washer 2 as a buffer. Absorbing.

[0003]

Recently, the length of the honeycomb catalyst carrier may be increased in order to improve the degree of purification of exhaust gas and combustion gas, or to improve the air permeability of the honeycomb catalyst carrier. In the above conventional support structure, since the honeycomb catalyst carrier is held and fixed to the casing at both ends thereof, the mesh washer needs to absorb the difference in thermal expansion and contraction between the carrier and the casing over the entire length of the honeycomb catalyst carrier. However, when the length of the honeycomb catalyst carrier becomes longer as described above, the mesh washer cannot absorb the difference in thermal expansion and contraction between the honeycomb catalyst carrier and the casing, and at the time of high temperature, the thermal expansion is made of a small ceramic material. The holding power to hold the honeycomb catalyst carrier is lost,
There is a risk that the honeycomb catalyst carrier will move inside the casing, causing cracks and chips. In order to prevent this, if a sufficient holding force is maintained even at the time of expansion at high temperature, the mesh washer needs to be excessively compressed at low temperature, and there is a risk that the honeycomb catalyst carrier will be cracked or chipped.

The present invention solves the above problems, and an object of the present invention is to provide a ceramic honeycomb catalyst carrier and a metal casing that covers the honeycomb catalyst carrier even when the honeycomb catalyst carrier has a long length. It is an object of the present invention to provide a ceramic honeycomb catalyst converter provided with a honeycomb catalyst carrier support structure that does not have a risk of causing cracks or chips in the honeycomb catalyst carrier due to the difference in thermal expansion and contraction.

[0005]

Means for Solving the Problems The present invention which achieves the above-mentioned object is to provide a honeycomb catalyst carrier made of ceramic, a metal casing covering the honeycomb catalyst carrier, and a cushioning body interposed between the honeycomb catalyst carrier and the casing. In the ceramic honeycomb catalytic converter including, a fixing portion for locally fixing the honeycomb catalyst carrier to the casing with a buffer interposed is provided at one end side in the longitudinal direction of the honeycomb catalyst carrier, and the other end side of the honeycomb catalyst carrier is provided. Is not fixed to the casing.

[0006]

In the ceramic honeycomb catalytic converter of the present invention, the honeycomb catalyst carrier is not fixed to the casing by holding and fixing both ends of the honeycomb catalyst carrier as in the conventional case. A fixing portion for locally fixing the honeycomb catalyst carrier to a metal casing with a buffer interposed is provided at one end side in the longitudinal direction of the honeycomb catalyst carrier, and the other end side of the honeycomb catalyst carrier is in the casing. Since it is not fixed, the buffer body of the fixed portion is, regardless of the length of the entire honeycomb catalyst carrier, at most, the length of the locally fixed portion, in the case of the examples described below, the length of the honeycomb catalyst carrier. Absorbs the difference in thermal expansion and contraction between the ceramic and the metal that occurs in the flange portion provided on the outer periphery of one end in the direction, and hence the extremely small difference Only good at.

That is, the difference in thermal expansion and contraction between the ceramic honeycomb catalyst carrier and the metal casing occurring over the entire length of the honeycomb catalyst carrier does not affect the holding and fixing of the honeycomb catalyst carrier according to the present invention in the casing. Not relevant. Therefore, according to the present invention, even when the length of the honeycomb catalyst carrier is long, there is no possibility of causing inconvenience due to the difference in thermal expansion and contraction between the honeycomb catalyst carrier and the casing. Further, since the honeycomb catalyst carrier is fixed to the casing with the buffer body interposed, there is no possibility of damaging the honeycomb catalyst carrier.

[0008]

The present invention will be described in detail below with reference to the drawings of the embodiments. FIG. 1 is a sectional view of a first embodiment of the present invention,
FIG. 2 is an enlarged sectional view of a main part of a modified example of the first embodiment. FIG. 3 is an enlarged cross-sectional view of the essential parts of the second embodiment of the present invention.
FIG. 6 is a sectional view of a third embodiment of the present invention. The same reference numerals indicate the same parts.

In FIG. 1, reference numeral 11 denotes a ceramic honeycomb catalyst carrier, which carries a catalyst for purifying exhaust gas and combustion gas therein. This honeycomb catalyst carrier 11 is locally fixed to a metal casing 17 at a flange portion 12 formed on the outer periphery of one end in the longitudinal direction.
Explaining the structure of this fixing part, a mesh washer, which is a buffer formed by forming a knitted wire mesh, is attached from the end face of the flange part 12 that coincides with the end face 13 of the honeycomb catalyst carrier to the outer peripheral surface of the flange part. And fits on the end plate 18 of the casing 17. Then, the step portion 120 of the flange portion 12 is pressed by the flat plate ring-shaped press fitting 21 through the mesh washer 16 so that the end surface 13 presses the vertical step portion 19 of the end plate 18 through the mesh washer 15. By pressing, the flange portion 12 is sandwiched and fixed by the vertical step portion 19 of the end plate and the pressing metal fitting 21 via the mesh washers 15 and 16. In this clamped and fixed state, the push fitting 21 is fixed to the parallel side portion 20 of the end plate by, for example, welding,
A fixing portion for locally fixing the honeycomb catalyst carrier 11 to the casing is formed at one end side in the longitudinal direction.

In this fixing portion, since the length of the flange portion 12 which is sandwiched and fixed to the casing 17 through the mesh washers 15 and 16 is short, the difference in the coefficient of thermal expansion between the ceramic and the metal is caused during this period. The difference in thermal expansion and contraction that occurs is small, and is easily absorbed by the mesh washer, and the fixed portion is not affected by the difference in thermal expansion and contraction between ceramic and metal. On the other hand, the other end 14 of the honeycomb catalyst carrier 11 is only loosely supported by the mesh washer 22 which is a buffer body formed by forming a wire mesh, and is not fixed to the casing 17. Therefore, the honeycomb catalyst carrier 11 can be freely expanded and contracted. In FIG. 1, 23 is a casing main body and 24 is a connecting flange.

The modification shown in FIG. 2 is different from the embodiment shown in FIG. 1 only in the shape of the pressing member for pressing the step 120 of the flange 12 with the mesh washer 16 interposed.
The other points are similar to those of the first embodiment shown in FIG. Figure 2
In the modified example shown in FIG. 1, the pressing member 25 is a ring having an inverted L-shaped cross section, which has a pressing side 251 and a parallel side 252, and the parallel side 252 is fitted to the outer periphery of the parallel side portion 20 of the end plate 18. In the same manner as in the above case, the honeycomb catalyst carrier 11
When the step portion 120 of the flange portion 12 is pressed through the mesh washer 16 so that the end surface 13 of the end plate 13 is pressed by the vertical step portion 19 of the end plate 18 through the mesh washer 15, the parallel side portion of the end plate is pressed. Two
It is fixed to 0 by welding or the like. Reference numeral 26 indicates a welded portion. Although not shown in FIG. 2, the other end portion 14 of the honeycomb catalyst carrier 11 is only loosely supported by the mesh washer 22 as in the case of FIG.
Not fixed to the casing.

In the second embodiment shown in FIG. 3, the mesh washers 15 and 16 are partially covered by a metal cover 27 and a push cover 28, and are integrally connected to them by caulking or the like. Then, so that the cover 27 and the push cover 28 are in contact with the end plate 18,
To put it the other way around, the mesh washer, which is a buffer, is mounted between the end plate 18 and the flange 12 so as to come into contact with the end face and the flange of the honeycomb catalyst carrier. The push cover 28 is pressed toward the step 120 of the flange portion 12, and the push cover 28 is pressed against the end plate 1.
By fixing to the parallel side portion 20 of 8 by welding or the like,
The flange portion 12 of the honeycomb catalyst carrier 11 is sandwiched and fixed between the vertical step portion 19 of the end plate and the push cover 28 via the mesh washers 15 and 16 which are buffer bodies, and the honeycomb catalyst carrier is locally fixed on one end side thereof. The fixing portion is formed to be fixed. In this embodiment, since the mesh washers 15 and 16 are integrated with the cover 27 and the push cover 28, there is an advantage that they are easy to handle and easy to insert and mount. Further, since a part of the mesh washer is covered by the cover, there is an effect that the gas bypassed through the mesh washer is reduced.

In the third embodiment shown in FIG. 4, the honeycomb catalyst carrier 11 is provided with an annular recess 29 having a bottom surface 30 which is tapered in the longitudinal direction on the outer periphery of one end in the longitudinal direction. The end plate 18 of the casing 17 is locally formed in this tapered bottom recess.
Fixed to. That is, on the outer periphery of one end of the honeycomb catalyst carrier 11, there is formed an annular recess 29 having a bottom surface 30 that is tapered in the longitudinal direction so that the depth gradually increases as the distance from the end surface 13 increases. 29
A ring-shaped mesh washer (buffer) 31 having an L-shaped cross section is attached to the end face 13 and the end surface 13, and the honeycomb catalyst carrier 11 is attached to the vertical step portion 19 and the parallel side portion 20 of the end plate 18 of the casing 17. Fit in.
And the parallel side portion 20 of the end plate and the tapered bottom surface 3
The taper bush 32 having a wedge-shaped cross section is pressed between the mesh washer 31 and the mesh washer 31 mounted in the concave portion 29 having 0, and the honeycomb catalyst carrier 11 is firmly fixed to the end plate 18 through the mesh washer 31 by the wedge action. Fix it. The taper bush 32 is fixed to the parallel side portion 20 by welding or the like while being pushed.

On the other hand, the other end 14 of the honeycomb catalyst carrier 11 is only loosely supported by the mesh supporter 33 and is not fixed to the casing, and the honeycomb catalyst carrier 11 can freely expand and contract by heat. . In addition, in this embodiment, one end of the honeycomb catalyst carrier which is locally fixed to the casing is arranged downward, the other end which is not fixed to the casing is arranged upward, and the entire ceramic honeycomb catalytic converter is arranged so as to be inclined. With such an inclined arrangement, the honeycomb catalyst carrier 11 can be more locally fixed to the casing 17. Therefore, such an inclined arrangement is not limited to the third embodiment, and can be advantageously applied to any of the first embodiment shown in FIG. 1, its modification shown in FIG. 2 and the second embodiment shown in FIG. .

[0015]

The ceramic honeycomb catalytic converter of the present invention has the structure as described above, and since the honeycomb catalyst carrier is locally fixed to the casing at one end side thereof via the buffer, Since the honeycomb catalyst carrier is fixed to the end plate of the casing through a buffer at a flange portion provided on the outer periphery of one end in the longitudinal direction or a recess having a bottom surface that is tapered in the longitudinal direction, the cushioning of this fixing portion is performed. The body need only absorb at most the difference in thermal expansion and contraction between the ceramic and the metal that occurs at the local anchor, regardless of the overall length of the honeycomb catalyst support. That is, the difference in thermal expansion and contraction between the ceramic honeycomb catalyst carrier and the metal casing that occurs over the entire length of the honeycomb catalyst carrier is independent of the fixing of the honeycomb catalyst carrier to the casing according to the present invention, and has no effect. . Therefore, according to the present invention, even when the length of the honeycomb catalyst carrier is long, the holding force for holding the honeycomb catalyst carrier is lost due to the difference in thermal expansion and contraction between the honeycomb catalyst carrier made of ceramic and the casing made of metal. The honeycomb catalyst carrier can be held and fixed well without the risk of the honeycomb catalyst carrier moving in the casing and causing cracks or chips, or the honeycomb catalyst carrier being cracked or chipped due to excessive stress. .

[Brief description of drawings]

FIG. 1 is a sectional view of a first embodiment of the present invention.

FIG. 2 is an enlarged sectional view of an essential part of a modified example of the first embodiment.

FIG. 3 is an enlarged sectional view of a main part of a second embodiment of the present invention.

FIG. 4 is a sectional view of a third embodiment of the present invention.

FIG. 5 is a sectional view of a conventional ceramic honeycomb catalytic converter.

[Explanation of symbols]

 11 Honeycomb catalyst carrier 12 Flanges 15, 16 and 31 Mesh washer 17 Casing 18 End plate 21 and 25 Push metal fitting 29 Recess 32 Tapered bush

Claims (4)

[Claims] 1. A ceramic honeycomb catalyst converter comprising a ceramic honeycomb catalyst carrier, a metal casing enclosing the ceramic honeycomb carrier, and a buffer body interposed between the honeycomb catalyst carrier and the casing. A ceramic is characterized in that a fixing portion for locally fixing to the casing with a buffer interposed is provided at one end side in the longitudinal direction of the honeycomb catalyst carrier, and the other end side of the honeycomb catalyst carrier is not fixed to the casing. Honeycomb catalytic converter. 2. The ceramic honeycomb catalytic converter according to claim 1, wherein the fixing portion for fixing the honeycomb catalyst carrier is provided with a flange portion on the outer periphery of one end in the longitudinal direction of the honeycomb catalyst carrier, and the end face of the flange portion is a buffer body. To press the vertical step of the end plate of the casing with a cushion, the step of the flange is pressed by a pressing metal fitting, and the flange is pressed against the vertical step of the end plate and the metal fitting. A ceramic honeycomb catalytic converter characterized in that it is sandwiched by and a push metal member is fixed to the end plate by welding or the like. 3. The ceramic honeycomb catalytic converter according to claim 1, wherein the fixing portion for fixing the honeycomb catalyst carrier is provided with a recess having a longitudinally tapered bottom surface on the outer periphery of one end in the longitudinal direction of the honeycomb catalyst carrier. An annular cushioning body is mounted over the concave portion and the end surface of the one end, and the cushioning body is provided inside an end plate having parallel side portions parallel to the longitudinal direction of the honeycomb catalyst carrier and step portions perpendicular to the parallel side portions. The honeycomb catalyst carrier fitted with is fitted, and a tapered bush having a wedge-shaped cross section is pushed between the parallel side portion of the end plate and the buffer body, and the tapered bush is fixed to the end plate by welding or the like. A ceramic honeycomb catalytic converter characterized by being formed as follows. 4. The casing is arranged so as to be inclined in the vertical direction, and a fixing portion for locally fixing the honeycomb catalyst carrier to the casing is located at a lower portion of the inclination. 3. The ceramic honeycomb catalytic converter described in 3.