JPH07102961A - Holding member for catalytic converter - Google Patents

Abstract

PURPOSE:To provide a ceramic fiber made holding member of high axial holding force to be used by being wound on the outer face of a catalysis carrier stored in the casing of a catalytic converter. CONSTITUTION:A ceramic fiber of 30mm long or more is orientated and laminated to one direction and a mat shaped laminated member 4 is formed and the laminated member 4 is sewn up by a heat eliminating fiber 5 and compressed. The laminated member 4 is wound on the outer face of a catalysis carrier 2 so that orientating direction of the ceramic fiber can be set along the axial direction of the catalysis carrier. A casing is assembled by putting the laminated member 4 between both half parts of the casing under this condition and further compressing the laminated member so as to mutually connecting both half parts. Then the casing is heated to eliminate the fiber 5.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a holding material applied to a catalytic converter for purifying exhaust gas of automobiles.

[0002]

2. Description of the Related Art A catalytic converter is constructed by accommodating a catalyst carrier having a large number of through holes penetrating in the axial direction in a casing. In this case, the catalyst carrier is protected from external force and stable in the casing. In order to hold the catalyst carrier, a holding material is generally interposed between the outer surface of the catalyst carrier and the inner surface of the casing.

This holding material is required to have heat resistance and corrosion resistance,
Therefore, attempts have been made to form the holding material with ceramic fibers.In this case, in order to hold the catalyst carrier stably, the ceramic fibers are uniformly and sufficiently compressed between the casing and the catalyst carrier. You need to wear it.

Therefore, conventionally, Japanese Patent Publication No. 51-42257.
As can be seen in Japanese Patent Publication, ceramic fibers are placed in a vinyl bag and evacuated to precompress the ceramic fibers, and the ceramic carrier is wound around the catalyst carrier. It is known that the halves are sandwiched, the ceramic halves are further compressed and the two halves are joined together to assemble the chaming, and then the vinyl bag is extinguished by heat.

[0005]

In the above-mentioned conventional example, the ceramic fiber can be sufficiently compressed and interposed between the casing and the catalyst carrier, but a large amount of the ceramic fiber is pre-compressed when the bag disappears. There is a problem that harmful gas is generated,
Also, because the ceramic fibers are oriented in an amorphous way,
There is a problem in that the axial holding force of the catalyst carrier is insufficient and the catalyst carrier tends to shift in the axial direction.

In view of the above points, an object of the present invention is to provide a holding material for a catalytic converter, which is capable of preventing the generation of harmful gas and improving the axial holding force of the catalyst carrier. I am trying.

[0007]

[Means for Solving the Problems] In order to achieve the above object,
The present invention is a holding material wound around the outer surface of a catalyst carrier housed in the casing of a catalytic converter and having a length of 30 mm.
It is characterized in that the above-mentioned ceramic fibers are oriented in the axial direction of the catalyst carrier to be laminated in a mat shape, and the mat-shaped laminated body is sewn and compressed by the fiber which disappears by heat.

[0008]

[Function] Since the mat-shaped ceramic fiber laminate is pre-compressed by the heat-dissipative fiber, the ceramic fiber can be sufficiently inserted by sandwiching it between the two halves of the casing while being wound around the catalyst carrier. Can be compressed to. Then, after assembling the casing by joining the two halves, the above-mentioned fiber is extinguished by heating the camming. However, unlike the conventional bag for precompression, this fiber does not require airtightness and thus is a normal natural fiber. It does not generate harmful gas when it disappears. Even if this fiber is used as a synthetic resin, its amount used is much smaller than that of a bag, and the amount of harmful gas generated at the time of disappearance is very small.

Further, since the ceramic fibers are oriented in the axial direction of the catalyst carrier and the fiber length is as long as 30 mm or more, the holding material is less likely to be deformed in the axial direction of the catalyst carrier, and the catalyst carrier is held in the axial direction. Power improves.

[0010]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1 shows a catalytic converter for an automobile, in which a catalyst carrier having a large number of axially penetrating through holes in a casing 1 composed of a pair of halves 1a and 1b divided into two parts. The body 2 is housed and held via a holding material 3 wound around the outer surface of the carrier 2.

The holding material 3 is composed of a mat-like laminated body 4 as shown in FIG. 2 (a) in which ceramic fibers having a length of 30 mm or more are oriented and laminated in one direction. As shown in FIG. 2 (b), fibers 5 such as natural fibers that disappear by heat
To sew and compress. In the laminated body 4, the length in the orientation direction of the ceramic fibers is substantially equal to the axial length of the catalyst carrier 2, the length in the direction orthogonal to this is substantially equal to the circumferential length of the catalyst carrier 2, and at one end. It is cut into a shape having a convex portion 4a and a concave portion 4b at the other end.

The mat laminate 4 thus obtained
As shown in FIG. 2 (c), is wound around the outer periphery of the catalyst carrier 2 so that the orientation direction of the ceramic fibers is along the axial direction of the catalyst carrier 2, and the convex portion 4a is fitted into the concave portion 4b. The carrier 2 is sandwiched between the two halves 1a and 1b of the casing 1, and the mat-like laminated body 4 is further compressed by the both halves 1a and 1b while joining the two halves 1a and 1b to each other.
Then, the casing 1 is heated to extinguish the fibers 5.

According to this, the mat-like laminated body 4 of the ceramic fibers as the holding material 3 is uniformly and sufficiently compressed between the casing 1 and the catalyst carrier 2, and the orientation direction of the ceramic fibers is also the catalyst carrier. Since it is along the axial direction of the body 2, the strength of the holding material in the axial direction is high, and the catalyst carrier 2 is stably held in the casing 1 without any axial displacement.

Alumina, alumina silica, and alumina-silica magnesia are suitable as the material of the ceramic fiber. In this case, if the α-conversion rate of alumina is high, it becomes brittle. % Or less, and when the shot amount in the fiber is large, the fiber is easily broken. Therefore, it is desirable to suppress the content of the shot having a diameter of 50 μm or more in the fiber to 5 wt% or less.

Furthermore, in order to further increase the axial holding force of the catalyst carrier 2, inorganic fibers that are not burned may be sewn into the mat-shaped laminate 4 to prevent axial displacement of the ceramic fibers. , To increase the compressive force of the holding material,
A thermally expansive fiber such as vermiculite may be mixed in the mat-shaped laminate 4.

[0016]

As is apparent from the above description, according to the present invention, the mat-shaped laminated body of the ceramic fibers, which is the holding material, is wound around the catalyst carrier in a pre-compressed state. Since the ceramic fibers can be sufficiently compressed and pre-compression is performed with the fibers sewn into the laminated body, the generation of harmful gas when the heat is lost can be suppressed as much as possible, and further, the ceramic fibers are oriented in the axial direction of the catalyst carrier. Therefore, the catalyst carrier can be stably held in the casing without axial displacement.

[Brief description of drawings]

FIG. 1 is a partially cutaway side view of a catalytic converter including a holding material of the present invention.

FIG. 2 (a) is a development view of an example of the holding material of the present invention, (b)
Partial enlarged cross-sectional view, (c) perspective view of the holding member in a wound state.

[Explanation of symbols]

1 casing, 2 catalyst carrier, 3 holding material, 4 laminated body, 5 fibers

Claims (1)

[Claims] 1. A holding material wound around the outer surface of a catalyst carrier housed in a casing of a catalytic converter, having a length of 3 mm.
For a catalytic converter, characterized in that 0 mm or more of ceramic fibers are oriented in the axial direction of the catalyst carrier to be laminated in a mat shape, and the mat-shaped laminated body is sewn and compressed with heat-dissipating fibers. Holding material.