Metal deforming – By use of tool acting during relative rotation between tool... – Tool orbiting or rotating about an axis
Reexamination Certificate
2003-02-28
2004-08-03
Lefkowitz, Edward (Department: 2855)
Metal deforming
By use of tool acting during relative rotation between tool...
Tool orbiting or rotating about an axis
C029S890000
Reexamination Certificate
active
06769281
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of Invention
The present invention relates to a method of producing a container for holding a columnar member in a cylindrical housing, with a shock absorbent member wrapped around the columnar member, and more particularly a method of producing a catalytic converter for holding a catalyst substrate with a shock absorbent mat wrapped around it in a cylindrical housing, and relates to an apparatus of producing the same.
2. Description of Related Arts
A container for holding a columnar member having a honeycomb structure and functioning as a fluid filter in a metallic cylindrical housing through a shock absorbent member has been used for a fluid treatment device, and provided for purifying various fluids. In an exhaust system of an automotive vehicle, for example, a catalytic converter, a diesel particulate filter (abbreviated as DPF) and the like have been used, and equipped with a fragile ceramic columnar member of a honeycomb structure, for a catalyst substrate, filter or the like (hereinafter, referred to as catalyst substrate). The honeycomb columnar member is held in the metallic cylindrical housing thorough the shock absorbent member such as a ceramic mat or the like, to constitute the fluid treatment device, an example of which is the catalytic converter. In order to produce the container for holding the columnar member such as the catalytic converter, generally employed is such a method for wrapping the shock absorbent member around the catalyst substrate, and stuffing them into the cylindrical housing, with the shock absorbent member being compressed.
For example, Japanese Patent Laid-open Publication No. 2001-355438 proposes a method of producing a catalytic converter, by measuring the outer diameter of a catalyst substrate, when the catalyst substrate with a holding material mounted around its periphery is stuffed (pressed) into a holding cylinder, and then stuffing the catalyst substrate with the holding material mounted thereon into the holding cylinder with its inner diameter adapted for the measured outer diameter. Also, it is proposed to measure the outer diameter of the holding material mounted on the catalyst substrate, and stuff the catalyst substrate with the holding material mounted thereon into the holding cylinder with its inner diameter adapted for the measured outer diameter. Furthermore, it is proposed to measure the outer diameter of the holding material in such a state that a certain pressure is applied to the holding material. It is also proposed to select a holding cylinder having a proper inner diameter, out of a plurality of holding cylinders with various inner diameters different from one another, which were provided in advance.
In contrast, it is proposed such a method called as “sizing” or “calibrating”, wherein after the catalyst substrate and a shock absorbent mat mounted thereon were inserted into a cylindrical member, the diameter of the cylindrical member is reduced until the shock absorbent mat will be compressed to the most appropriate compressed amount, as disclosed in Japanese Patent Laid-open Publication Nos. 64-60711, 8-42333, 9-170424, 9-234377, U.S. Pat. Nos. 5,329,698, 5,755,025, 6,389,693, and European Patent Publication No. EP0982480A2 and so on. Among them, in Japanese Patent Laid-open Publication No. 9-234377, it is proposed to reduce a casing along its entire longitudinal length, in order to solve a problem in its prior art as disclosed in Japanese Patent Laid-open Publication No. 2-268834. In the former Publication, it is stated about the latter Publication that there is disclosed a catalytic converter with a central portion of a tubular body reduced in diameter to form a compressed portion, and compress a support mat to support a ceramic honeycomb body in the casing. And, it is stated in the former Publication that the above problem will be caused, as a clearance between the outer circumference of the honeycomb body and the inner circumference of the casing is large in a direction from an end of the compressed portion toward cone portions which are not reduced in diameter.
In the U.S. Pat. No. 5,755,025, a process for manufacturing catalytic converters is proposed, as described in its abstract, by pushing monoliths and a surrounding support jacket into prefabricated tubes, whose cross section essentially corresponds to the profile of the monolith plus an addition for the support jacket. In the abstract, it is described that the dimensions of the tube (housing) are adapted to a constant gap(s) from the monolith by sizing (calibrating) the prefabricated tubes which initially have a smaller cross section. Thus, substantially the same process as stuffing the substrate and mat into the housing as described before has been employed. Furthermore, in the U.S. Pat. No. 6,389,693, a method of manufacturing a catalytic converter is proposed, by resizing a container over substantially the entire portion of its length which is occupied by the wrapped substrate to a predetermined metal shell/container outside diameter (OD). The predetermined outside diameter is characterized by the equation OD=D+2T1+2T2, wherein “D” is a diameter measure of the substrate, “T1” is the supporting mat target thickness and “T2” is a container wall thickness measure. Likewise, in the European Patent Publication No. EP0982480A2, it is described in its abstract that the subsequent to loading a mat and substrate into a can, the measurement of the substrate is used to direct the degree to which the can is reduced in outside dimension such that a selected annulus is created between the substrate and can, the annulus being occupied by the mat.
With respect to Japanese Patent Laid-open Publication No. 2000-45762 cited in Japanese Patent Laid-open Publication No. 2001-355438, a method for reducing a cylindrical member by a spinning process. Furthermore, there is disclosed in Japanese Patent Laid-open Publication No. 2001-107725, a method for producing a catalytic converter by reducing a diameter of a cylindrical member with a shock absorbent member held therein to hold a substrate catalyst, according to a spinning process using a plurality of spinning rollers revolved about the cylindrical member. As for a necking process applied to an end portion of the cylindrical member, an offset spinning process is disclosed in Japanese Patent No. 2957153, and an oblique spinning process is disclosed in Japanese Patent No. 2957154. And, a spinning apparatus is disclosed in Japanese Patent Laid-open Publication No. 2001-137962.
In the Japanese Patent Laid-open Publication No. 2001-355438 as described above, it is described that it is preferable to measure the outer diameter of the holding material, in such a state that the holding material
3
is applied with the same pressure (holding pressure) as the pressure which will be applied to the holding material
3
when the catalyst substrate
2
is stuffed into (pressed into) the holding cylinder
1
. According to the method as described above, however, it is impossible to estimate the pressure which will be applied to the holding material in the later process, and no explanation about this matter has been described. Therefore, the above description that the holding material
3
is applied with the same pressure as the pressure which will be applied to the holding material
3
when the catalyst substrate
2
is pressed into the holding cylinder
1
, is merely a desire or hope, and nothing is disclosed to show that it will be possibly realized. In addition, it is described that as for a base member of the holding cylinder
1
, used is the one having its inner diameter which will enable to have the stuffed holding material
3
apply the appropriate pressure to the catalyst substrate
2
. It is also stated that it can be achieved to select the one having the appropriate inner diameter, out of a plurality of base members having different inner diameters from one another prepared in advance. Therefore, it is apparent that the holding cylinder
1
is not the one having its inner diame
Irie Tohru
Ota Masashi
Lefkowitz Edward
Miller T.
Oliff & Berridg,e PLC
Sango Co. Ltd.
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