JP4576025B2 - Method for manufacturing catalytic converter - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a catalytic converter used for an exhaust system of an internal combustion engine for automobiles and a method for manufacturing the same.
[0002]
[Prior art]
The catalytic converter as described above has a configuration in which a honeycomb body such as a ceramic honeycomb catalyst is accommodated and disposed in a cylindrical body. As a manufacturing method thereof, for example, a ceramic fiber or the like is formed around a honeycomb body formed in a substantially cylindrical shape as a whole. It is proposed to insert the honeycomb body and the tubular body by inserting the mat-like support body into a cylindrical tubular body and reducing the diameter of the entire circumference of the tubular body with a die or the like. ing.
[0003]
Further, one honeycomb body as described above is generally housed and arranged in the cylindrical body. However, even if the entire volume is the same, it is better to provide a plurality of honeycomb bodies because exhaust purification performance is better. There is also one in which a plurality of, usually two, honeycomb bodies are accommodated in one cylindrical body.
[0004]
However, honeycomb bodies such as those described above, particularly those made of ceramics, vary in outer diameter from rod to rod or from product to product, so the tubes around the honeycomb bodies housed in the tube are uniform. When the diameter reduction processing is performed with the same diameter reduction amount, there is a problem that the diameter reduction amount is small and rattling occurs, or the diameter reduction amount is large and the honeycomb body is damaged. In particular, the management width of the holding surface pressure needs to be set narrow due to the thinning of the honeycomb.
[0005]
In addition, both ends of the cylindrical body containing the honeycomb body as described above are generally drawn in a funnel shape, but the inner diameter dimension of the cylindrical body between adjacent honeycomb bodies is usually the same as the inner diameter dimension around the honeycomb body. Since the exhaust gas that has passed through one honeycomb body enters the inner surface of the cylindrical body through the gap between the adjacent honeycomb bodies, the support body is formed of ceramic fibers or the like disposed between the cylindrical body and the honeycomb body. May be exposed to the exhaust gas, causing deterioration, or the fibers gradually fraying and scattering.
[0006]
[Problems to be solved by the invention]
An object of the present invention is to solve the above-described problems of a catalytic converter in which a plurality of honeycomb bodies as described above are accommodated in a cylinder.
[0007]
[Means for Solving the Problems]
In order to achieve the above object, the catalytic converter and the manufacturing method thereof according to the present invention are configured as follows.
[0008]
That is, the manufacturing method of the catalytic converter according to the present invention, a plurality of the honeycomb body, at predetermined intervals in the cylinder body accommodating arranged in a cylindrical body in a state wound each support on their outer periphery, the respective honeycomb In a method for manufacturing a catalytic converter in which a cylindrical body around a body is contracted and fixed , the outer diameter dimension of the cylindrical body at a position corresponding to between adjacent honeycomb bodies is set before performing the contraction processing. It is characterized in that it is formed to have a diameter smaller than the outer diameter of the cylinder around the honeycomb body after the warp processing .
[0009]
Further, the method for manufacturing a catalytic converter according to the present invention includes a plurality of honeycomb bodies that are accommodated and disposed at predetermined intervals in a cylindrical body in a state in which a support is wound around the outer periphery of each of the honeycomb bodies. In the method of manufacturing a catalytic converter in which the cylindrical body is fixed by reducing the diameter, before the diameter reducing process is performed, at least the outer diameter dimension of the cylindrical body at a position corresponding to between adjacent honeycomb bodies is reduced. When forming the small-diameter small-diameter portion, the inner diameter dimension of the small-diameter portion is substantially equal to or larger than the outer-diameter dimension of the honeycomb body. Before performing the diameter reducing process, the first step of forming a small diameter, and before performing the diameter reducing process, a sensor mounting nut is provided on the small diameter part of the cylinder between adjacent honeycomb bodies, and the outer surface thereof is from the cylinder after the diameter reducing process. Is also positioned radially inward Characterized in that it comprises a second step of fixing manner to.
[0010]
The method for manufacturing a catalytic converter according to the present invention is characterized in that the diameter reduction amount of the cylindrical body is adjusted according to the outer diameter dimension of the honeycomb body and the thickness dimension of the support body .
[0011]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, the catalytic converter and the manufacturing method thereof according to the present invention will be specifically described based on the embodiments shown in the drawings.
[0012]
FIG. 1 is a longitudinal sectional view showing an embodiment of a catalytic converter according to the present invention. In the figure, reference numeral 1 denotes a cylindrical body, which has a small diameter portion 1a formed at a substantially central portion in the longitudinal direction. The large diameter portions 1b and 1b on both sides of the small diameter portion 1a are entirely made of a substantially cylindrical ceramic honeycomb catalyst. A honeycomb body 2 is accommodated and disposed in a state in which a support body 3 formed by forming ceramic fibers in a mat shape is wound around the outer peripheral surface thereof.
[0013]
The inner diameter dimension of the small diameter portion 1a is formed to be equal to or smaller than the outer diameter dimension of the honeycomb body 2, and a nut 4 for attaching a sensor is provided in the small diameter portion 1a. In this embodiment, the nut 4 is configured to be integrally fixed by welding or the like in a state of being fitted in a hole formed in the small-diameter portion 1a, and a temperature sensor S or the like is attached to the nut 4 so that the inside of the catalytic converter is formed. The temperature of the flowing exhaust gas is detected. Further, both end portions 1c and 1c of the cylindrical body 1 are formed in a funnel shape, and exhaust pipes P1 and P2 are fitted and connected to respective tip portions thereof.
[0014]
As described above, when the inner diameter of the cylinder 1 between the adjacent honeycombs 2 and 2 accommodated in the cylinder 1 is formed to be equal to or smaller than the outer diameter of the honeycomb 2, the adjacent honeycombs 2 and 2 are formed. It is possible to reduce the flow of exhaust gas between the tubular body 1 and the honeycomb body 2 as much as possible, and to prevent the support body 3 from being altered or scattered as much as possible. is there.
[0015]
Next, when manufacturing the above-described catalytic converter, for example, it is manufactured in the following manner. That is, first, as shown in FIG. 2 (a), a cylindrical body 1 having a predetermined inner diameter is used, and a portion corresponding to a substantially intermediate position of a plurality of honeycomb bodies to be accommodated in the cylindrical body 1, in this embodiment As shown in FIG. 2B, a small diameter portion 1a is formed in the central portion of the cylindrical body 1 in the axial direction. In this case, if the cylindrical body 1 has an inner diameter dimension that is substantially the same as or slightly smaller than the outer dimension in the state where the support body 3 is wound around the outer peripheral surface of the honeycomb body 2 to be inserted. Good.
[0016]
The outer diameter of the small-diameter portion 1a is preferably at least smaller than the outer diameter of the cylinder around the honeycomb body after the diameter reduction processing, and the inner diameter of the small-diameter portion 1a is the outer diameter of the honeycomb body 2. It is desirable that the diameter is substantially the same as or smaller than that. As a means for forming the small-diameter portion 1a, spinning or other appropriate methods are used.
[0017]
Furthermore, when attaching the nut 4 for sensor attachment to the said small diameter part 1a, the hole of the magnitude | size which the nut 4 just fits in the said small diameter part 1a as shown, for example in FIG.2 (b), and the nut 4 is set in the hole. And are fixed by welding or the like. In that case, the outer surface of the nut 4 (surface on the outer side in the radial direction of the cylindrical body) is preferably positioned on the inner side in the radial direction with respect to the outer peripheral surface after the diameter reduction of the cylindrical body 1 around the honeycomb body described later.
[0018]
Next, as shown in FIG. 2B, the honeycomb body 2 is inserted into the cylindrical body 1 with the support 3 wound around the outer peripheral surface thereof. The insertion operation is performed simultaneously from both ends of the cylindrical body 1. You may go, or you may go one by one. Moreover, it can also insert using a jig | tool etc. suitably as needed.
[0019]
In a state where a plurality of honeycomb bodies 2 are inserted into the tubular bodies 1 as described above, the diameter of the tubular bodies 1 around each honeycomb body 2 is reduced over the entire length in the circumferential direction by a die D or the like, and the honeycomb bodies 2 are fixed. The diameter of the cylinder body 1, the honeycomb body 2, and the thermally expandable support body 3 at the exhaust temperature is such that the honeycomb body 2 can be expanded or contracted even if the support body is expanded or contracted. The diameter may be reduced to such an extent that it can be satisfactorily fixed without rattling or damaging the honeycomb body.
[0020]
In this case, the outer dimensions of the honeycomb body 2 are varied from lot to lot or individual products as described above, particularly for ceramics. In this case, the external dimensions are measured for each lot or for each product, and the above-mentioned diameter reduction amount is appropriately adjusted according to the measured dimensions.
In addition, when the density and thickness of the support body 3 vary, it is good to adjust the said diameter reduction amount also considering them.
[0021]
In addition, the above-mentioned adjustment of the diameter reduction is made so that the diameter of the die can be changed, or a plurality of types of dies having different diameter reductions are prepared and used selectively, or a plurality of types having different densities and thicknesses are used. It is also possible to prepare and use the support. Furthermore, it is possible to measure the outer dimensions of the honeycomb body and, if necessary, measure the density and thickness of the support 3 and automatically adjust the diameter reduction and select the die or the support based on the measurement. Is possible.
[0022]
When a plurality of honeycomb bodies 2 are fixed in the cylindrical body 1 as described above, both ends 1c and 1c of the cylindrical body 1 are formed in a funnel shape by spinning or the like, thereby completing a product as a catalytic converter. . Exhaust pipes P1 and P2 are connected to both ends of the completed catalytic converter as shown in FIG. 1 for use.
[0023]
As described above, when the diameter reduction amount at the time of diameter reduction processing of the cylindrical body 1 is adjusted according to the outer diameter size of each honeycomb body 2, the diameter reduction amount is small and rattling occurs, or the diameter reduction amount is large. Can be solved.
[0024]
Further, before the diameter reduction processing of the cylindrical body around each honeycomb body, the outer diameter dimension of the cylindrical body between adjacent honeycomb bodies is smaller than the cylindrical outer diameter around the honeycomb body after the diameter reduction processing, for example, When performing the above-mentioned diameter reduction processing with a die or the like, the diameter reduction processing can be satisfactorily performed by allowing the die or the like to pass through to the above-mentioned small diameter portion. Further, when the sensor mounting nut 4 is provided in the small diameter portion 1a, the nut 4 is fixed at least before the diameter reduction processing, and the outer surface of the nut 4 is the cylindrical body 1 around the honeycomb body. If it is located on the inner side in the radial direction from the outer peripheral surface when the diameter is reduced, there will be no obstacle during the diameter reduction processing.
[0025]
Further, when the nut 4 is fixed by welding or the like, there is a risk that thermal deformation or strain may occur in the cylinder. When the nut 4 is fixed after being drawn, the fixing pressure of the honeycomb body 2 is increased by the thermal deformation or strain. There is a risk of variations, support balance being lost and rattling, etc., but if it is fixed before performing diameter reduction as described above, the above disadvantages may occur. Can be prevented.
[0026]
【The invention's effect】
As described above, in the catalytic converter according to the present invention, the inner diameter dimension of the cylindrical body between the adjacent honeycomb bodies is formed to be equal to or smaller than the outer diameter dimension of the honeycomb body. It is possible to prevent as much as possible that the exhaust gas flows between the tubular body 1 and the honeycomb body 2 and the support body 3 is altered or scattered.
[0027]
Further, in the method for manufacturing the catalytic converter according to the present invention, the amount of diameter reduction during the diameter reduction processing of the tubular body 1 is adjusted according to the outer diameter size of each honeycomb body 2, so that the amount of diameter reduction is small and the backlash is reduced. Problems such as occurrence or damage of the honeycomb body due to a large amount of diameter reduction can be solved satisfactorily.
[0028]
Further, before the diameter reduction processing of the tubular body 1, the outer diameter size of the tubular body 1 between the adjacent honeycomb bodies 2 and 2 is formed to be smaller than at least the outer diameter of the cylindrical body surrounding the honeycomb body after the diameter reduction processing. Since it did in this way, when performing said diameter reduction process with a dice etc., for example, there exists an effect that the diameter reduction process can be performed favorably by making the die etc. pass through to said small diameter part.
[Brief description of the drawings]
FIG. 1 is a longitudinal sectional view showing an embodiment of a catalytic converter according to the present invention.
FIGS. 2A to 2D are explanatory views showing an example of a manufacturing process of a catalytic converter.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Tubular body 1a Small diameter part 1b Large diameter part 2 Honeycomb body 3 Support body 4 Nut D Dice S Temperature sensor P1, P2 Exhaust pipe

Claims (2)

A plurality of honeycomb bodies are accommodated and arranged at predetermined intervals in a cylindrical body in a state where a support is wound around each outer periphery thereof,
In the manufacturing method of the catalytic converter in which the cylindrical body around each honeycomb body is fixed by reducing the diameter,
Before performing the diameter reduction processing, the outer diameter of the cylindrical body at a position corresponding to between adjacent honeycomb bodies is made at least smaller than the cylinder outer diameter around the honeycomb body after the diameter reduction processing , and the small diameter A first step of forming an inner diameter dimension of the small diameter section substantially equal to or smaller than an outer diameter dimension of the honeycomb body when forming the small diameter section;
Before performing the diameter reduction processing, a sensor mounting nut is disposed in the small diameter portion of the cylindrical body between adjacent honeycomb bodies so that the outer surface thereof is positioned radially inward of the cylindrical body after the diameter reduction processing. A second step of fixing,
A method for producing a catalytic converter, comprising: 2. The method of manufacturing a catalytic converter according to claim 1, wherein a diameter reduction amount of the cylindrical body is adjusted in accordance with an outer diameter dimension of the honeycomb body and a thickness dimension of the support body.

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