JP2005171829A - Catalytic converter and its manufacturing method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a catalytic converter having a proper clearance between a catalyst and an outer cylinder so that the catalyst is stably held, and to provide its manufacturing method. <P>SOLUTION: In the catalytic converter 10, the catalyst 11 constituted by winding a mat 12 on its outer circumferential face is inserted into the outer cylinder 13, so that the catalyst 11 is fixed to the inside of the outer cylinder 13 by the face pressure of the mat 12. A pressure detection hole 14 is formed in a side face 13a of the outer cylinder 13 so as to detect repulsive force of the mat 12 with a state where the pressure detection hole faces the mat 12. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a catalytic converter capable of holding a catalyst in a stable state and a method for producing the same.

2. Description of the Related Art Conventionally, catalytic converters for purifying exhaust gas have been provided in exhaust systems of various engines including automobile engines. In general, a catalytic converter basically has a structure composed of a columnar catalyst, a mat wound around the catalyst, and an outer cylinder accommodating the catalyst wound around the mat (for example, Patent Document 1).
The mat wound around the catalyst is made of a heat-resistant fiber material and is interposed between the catalyst and the outer cylinder to ensure a sealing property that prevents unpurified exhaust gas from passing between the catalyst and the outer cylinder. And has various roles such as elastic retention of the catalyst and heat insulation between the catalyst and the outer cylinder. In particular, the mat plays a very important role in maintaining the performance of the catalytic converter for a long period of time.
In order to bring out such mat performance, it is desirable that the gap (interval) between the catalyst and the outer cylinder be uniform. Here, if there is a variation in the gap between the catalyst and the outer cylinder, the catalyst may be damaged due to a problem in sealing performance or a variation in the elastic holding force. It becomes difficult to maintain for a long time. In particular, a catalyst with improved exhaust efficiency has a thin wall, which causes problems such as breakage due to high heat and vibration during use.

Therefore, various methods for making the gap between the catalyst and the outer cylinder uniform have been proposed. As one of them, the surface pressure of the mat wound around the catalyst is detected, and when the surface pressure reaches a predetermined value, the distance between the catalyst core and the detection sensor is measured. Has proposed a method of adjusting the processing amount so that the distance from the axial center of the catalyst to the outer cylinder is the measured distance (see, for example, Patent Document 2).
Japanese Patent Laying-Open No. 2001-263052 (paragraphs 0019 to 0020, FIG. 2) JP 2003-286836 A (paragraphs 0019 to 0023, FIGS. 2 and 3)

However, in the method of detecting the surface pressure of the mat wound around the conventional catalyst and adjusting the diameter reduction processing amount, the distance when the surface pressure becomes a predetermined value is in a state suitable for the outer cylinder. Therefore, there is a possibility that the gap after the diameter reduction processing may not be a desired one even if the diameter reduction processing is performed on the basis of this distance. For this reason, there is a possibility that accurate diameter reduction processing may not be performed, and there is a problem that it is difficult to realize stable catalyst retention.
In addition, since the catalyst originally has a variation in diameter, and also has a twist and a bend, it is difficult to measure the distance from the catalyst core to the outer cylinder uniformly.

  Accordingly, an object of the present invention is to provide a catalytic converter that can make the gap between the catalyst and the outer cylinder an appropriate gap and can keep the catalyst in a stable state, and a method for manufacturing the same. .

  In the manufacturing method of the catalytic converter according to claim 1 of the present invention that has solved the above problems, a catalyst having a mat wound around an outer peripheral surface is inserted into an outer cylinder, and the catalyst is moved by the surface pressure of the mat. The catalytic converter is configured to be fixed inside an outer cylinder, and is characterized in that a pressure detection hole for detecting a repulsive force of the mat in a state of facing the mat is provided on a side surface of the outer cylinder.

According to the first aspect of the present invention, since the pressure detection hole for detecting the repulsive force of the mat is provided on the side surface of the outer cylinder, the repulsive force of the mat can be detected using the pressure detection hole. it can. In addition, since the pressure detection hole is provided so as to face the mat, the repulsive force can be detected in a state where the catalyst is actually mounted inside the outer cylinder. Therefore, even if there is a variation in the size of the catalyst, it becomes possible to perform the diameter reduction processing according to the size of the catalyst, and as a result, the gap between the catalyst and the outer cylinder is set to the optimum gap according to the catalyst. be able to.
As a result, the catalyst can be reliably held, and a catalytic converter that can withstand long-term use can be obtained.

  According to a second aspect of the present invention, in the catalytic converter according to the first aspect, the pressure detection hole is provided in a bulging portion that is bulged on a side surface of the outer cylinder.

  According to the second aspect of the present invention, since the pressure detection hole is provided in the bulging portion formed to bulge on the side surface of the outer cylinder, when the catalyst around which the mat is wound is inserted into the outer cylinder, This does not rub against the mat and damage the mat. Therefore, the sealing performance of the mat is not impaired, and stable catalyst retention can be realized.

  According to a third aspect of the present invention, in the catalytic converter according to the first or second aspect, a plurality of the pressure detection holes are provided.

  According to the third aspect of the present invention, since the plurality of pressure detection holes are provided, the repulsive force of the mat can be detected at a plurality of locations of the outer cylinder. Then, for example, an average value can be calculated from the detection values obtained by the pressure detection holes at the plurality of locations, and the value can be used as the repulsive force of the mat.

  According to a fourth aspect of the present invention, in the catalytic converter according to any one of the first to third aspects, a sealing member is provided between the mat facing the pressure detection hole and the outer cylinder. It is provided.

According to the invention described in claim 4, since the sealing member is provided between the mat facing the pressure detection hole and the outer cylinder, the sealing property between the mat facing the pressure detection hole and the outer cylinder is improved. This can increase the possibility of unpurified exhaust gas leaking through the pressure detection hole.
As a result, a catalytic converter having a sealing property can be obtained despite the structure that can detect the repulsive force of the mat through the pressure detection hole.

  The invention according to claim 5 is a catalyst in which a catalyst having a mat wound around its outer peripheral surface is inserted into the outer cylinder, and the catalyst is fixed inside the outer cylinder by the surface pressure of the mat. A method of manufacturing a converter, wherein the repulsive force of the mat of the catalyst inserted into the outer cylinder is detected, and the repulsive force becomes a predetermined repulsive force based on the detection result. The cylinder is reduced in diameter.

According to the fifth aspect of the present invention, the catalyst having the mat wound around the outer peripheral surface is inserted into the outer cylinder, and the repulsive force of the mat is detected in this state, and the repulsion is based on the detection result. Since the outer cylinder is reduced in diameter so that the force (surface pressure) has a predetermined repulsive force, the diameter reduction process is based on the repulsive force when the catalyst is actually mounted inside the outer cylinder. It can be performed. Therefore, even if there is a variation in the size of the catalyst, it becomes possible to perform the diameter reduction processing according to the size of the catalyst, and as a result, the gap between the catalyst and the outer cylinder is set to the optimum gap according to the catalyst. be able to.
Therefore, the catalyst can be reliably held, and a catalytic converter that can withstand long-term use can be obtained.

  According to a sixth aspect of the present invention, in the catalytic converter manufacturing method according to the fifth aspect, the detection of the repulsive force of the mat is a pressure detection hole provided on the side surface of the outer cylinder so as to face the mat. It is characterized by being conducted through.

  According to the invention described in claim 6, since the repulsive force of the mat is detected through the pressure detection hole provided on the side surface of the outer cylinder so as to face the mat, the repulsive force is detected through the pressure detection hole. It can be done easily.

  According to a seventh aspect of the present invention, in the method of manufacturing a catalytic converter according to the sixth aspect, a plurality of the pressure detection holes are formed on a side surface of the outer cylinder, and the repulsive force of the mat is detected It is performed in each of a plurality of formed pressure detection holes.

  According to the seventh aspect of the present invention, the repulsive force can be easily detected at a plurality of locations through a plurality of pressure detection holes formed on the side surface of the outer cylinder.

  ADVANTAGE OF THE INVENTION According to this invention, the clearance gap between a catalyst and an outer cylinder can be formed in a suitable clearance gap, and the catalytic converter which can hold | maintain a catalyst in the stable state is obtained.

Hereinafter, a catalytic converter according to an embodiment of the present invention will be described with reference to the drawings.
In the drawings to be referred to, FIG. 1 is a perspective view of a catalytic converter according to an embodiment of the present invention, FIG. 2 is a perspective view showing a state when the catalyst is inserted into an outer cylinder during production, and FIG. It is a longitudinal cross-sectional view of a catalytic converter.

  As shown in FIGS. 1 and 2, the catalytic converter 10 of the present embodiment includes a catalyst carrier (hereinafter referred to as a catalyst) 11 having a cylindrical shape and a high cell density, a mat 12 wound around the outer periphery thereof, The outer cylinder 13 covers the catalyst 11 in a state where the mat 12 is wound. The catalyst 11 is held in the outer cylinder 13 with a predetermined gap S that is the thickness of the mat 12.

  The catalyst 11 is a substantially cylindrical cordierite monolith carrying an exhaust gas purifying catalyst such as platinum. As shown in FIG. 3, a plurality of honeycomb-shaped passages 11a extending in the axial direction are formed inside. ing. When the exhaust gas passes through the honeycomb-shaped passage 11a, exhaust gas components contained in the exhaust gas are purified through the porous cell walls forming the honeycomb-shaped passage 11a.

The mat 12 is formed by forming a mixture of silica / alumina ceramic fiber, unexpanded vermiculite, an inorganic binder and an organic elastic material into a sheet shape, and holds the catalyst 11 in the outer cylinder 13, It serves to prevent the exhaust gas from leaking from between the outer cylinder 13. The mat 12 holds the catalyst 11 with a constant surface pressure by a diameter reduction process described later. In the present embodiment, the mat 12 having a thickness of 8 mm and a density of 0.3 g / cm ³ can be expected to exhibit a holding force sufficient to hold the catalyst 11 in the outer cylinder 13 by the diameter reduction processing described later. Is used.

The outer cylinder 13 is made of a ferrous material such as stainless steel and is formed in a substantially circular cylindrical shape. The outer cylinder 13 has a body shape that can accommodate the catalyst 11 wound around the mat 12 therein.
A pressure detection hole 14 for detecting the repulsive force of the mat 12 is provided on the side surface 13 a of the outer cylinder 13. As shown in FIG. 3, the pressure detection hole 14 is provided so as to penetrate the side surface 13a of the outer cylinder 13, and the surface of the mat 12 faces the inside 14a of the hole. A pressure detection sensor 15 is disposed on the side of the pressure detection hole 14 as shown in FIG. 4A when detecting the repulsive force of the mat 12 described later.
In the present embodiment, a piezoelectric internal pressure sensor is used as the pressure detection sensor 15. The pressure detection sensor 15 is held by an advancing / retreating mechanism (not shown) so as to advance and retreat with respect to the pressure detection hole 14 of the outer cylinder 13, and as shown in FIG. The front end portion 15a enters the hole 14a and comes into contact with the mat 12 to press it. The distal end portion 15a of the pressure detection sensor 15 is inserted into the pressure detection hole 14 without a substantial gap. That is, the pressure detection hole 14 is formed as small as possible.
In addition, a cone-shaped exhaust passage (not shown) is integrally formed on the opening edges on both sides of the outer cylinder 13 by welding or the like after the diameter reduction processing described later.

  FIG. 5 is a diagram for explaining the diameter reduction processing when manufacturing such a catalytic converter 10, wherein (a) is a schematic view of the catalytic converter at the time of diameter reduction viewed from the side, and (b). These are the conceptual diagrams which represented the catalyst converter circumference with the cross section. In the present embodiment, a diameter reduction process performed by swaging will be described. The adjustment of the diameter reduction processing amount by the swaging device 20 is configured to be performed based on the detection result of the repulsive force of the mat 12 by the pressure detection sensor 15.

Hereinafter, each part will be described. As shown in FIG. 5A, the swaging apparatus 20 includes a swaging die 21 having a plurality of fingers 21a and a swaging collar having an inner wall surface 22b in which the fingers 21a of the swaging die 21 are in sliding contact. 22 and at least a slider 23 for causing the swaging die 21 to make a ram stroke, as shown in FIG.
In the swaging die 21, the slidable contact surface 21b of each finger 21a with respect to the swaging collar 22 is formed so as to be inclined downward in the ram stroke direction of the swaging die 21 (arrow A direction in FIG. 5B: insertion direction). ing. Further, the swaging collar 22 has a shape that matches the sliding contact surface 21 b of the swaging die 21, so that when the swaging die 21 is inserted into the swaging collar 22, the swaging collar 22 changes to the swaging collar 22. When pressed, it is configured to move in the direction of diameter reduction (the direction of arrow B in FIG. 5A). In this embodiment, the swaging die 21 composed of a total of twelve fingers 21 a that can wrap the entire periphery of the outer cylinder 13 is used. The number of fingers 21a may be adjusted as appropriate depending on the size of the outer cylinder 13 and the like.

Such a swaging die 21 is configured to slide in the ram stroke direction or the counter ram stroke direction by the slider 23.
The drive control of the slider 23 is performed by the drive control unit 24, and the drive control of the slider 23 by the drive control unit 24 is performed based on the detection result of the repulsive force of the mat 12 by the pressure detection sensor 15. It has come to be. The drive control unit 24 stores a data table that defines the drive control amount (specifically, the ram stroke drive amount of the swaging die 21) of the slider 23 corresponding to the detected value of the repulsive force of the mat 12. In addition, the detection value by the pressure detection sensor 15 is input, and the slider 23 is driven and controlled by a drive control amount corresponding to the detection value. Here, it is desirable that the drive control amount of the slider 23 is set in consideration of the strength and outer diameter size of the material of the catalyst 11 and the elasticity and thickness of the material of the mat 12. In this embodiment, the design value of the gap S is 3.6 mm ± 0.3 mm, and the slider 23 is driven and controlled so that the gap S becomes this value.

  The drive control amount of the slider 23 is set as a value in consideration of the influence of the springback of the outer cylinder 13 while avoiding the risk of damage of the catalyst 11 and the collapse of the mat 12 by conducting an experiment or the like in advance. You can also.

When drive control of the ram stroke of the slider 23 is performed by the drive control unit 24, the swaging die 21 is driven in the diameter reduction direction. As a result, the catalytic converter 10 is reduced in diameter by a desired diameter reduction processing amount. To be processed.
Further, the drive control unit 24 drives the slider 23 to move backward in the anti-ram stroke direction after the diameter reduction processing, and sends a signal for releasing the holding state by the swaging device 20 to the swaging device 20. Yes.

Next, the manufacturing method of the catalytic converter 10 using such a swaging apparatus 20 is demonstrated. Prior to swaging, the mat 12 is wound around the outer periphery of the catalyst 11. Then, the ends of the wound mat 12 are stuck together with a nonflammable tape material (not shown). In addition, you may make it stick with a combustible tape material.
At this time, the mat 12 is configured such that convex portions and concave portions (not shown) that engage with each other are formed in both ends in advance, and are wound so as to engage with each other during winding. Also good. Further, a metal sealing material or the like may be wound around the wound mat 12 to reduce the thickness of the mat 12 or improve the sealing performance. In addition, as shown in FIG. 6, a seal member 16 may be provided between the mat 12 facing the pressure detection hole 14 and the outer cylinder 13. By providing such a sealing member 16, the sealing performance between the mat 12 facing the pressure detection hole 14 and the outer cylinder 13 can be improved, and there is a possibility that unpurified exhaust gas leaks through the pressure detection hole 14. Disappear. As a result, the catalytic converter 10 having a structure capable of detecting the repulsive force of the mat 12 through the pressure detection hole 14 and having a sealing property is obtained.
The seal member 16 is formed in a thin sheet shape using a material such as carbon fiber.

  Thereafter, the catalyst 11 around which the mat 12 is wound is inserted (press-fitted) into the outer cylinder 13. At the time of insertion, a funnel-shaped guide member 17 as shown in FIG. 2 is used. Thus, the catalyst 11 can be smoothly inserted into the outer cylinder 13, and the mat 12 can be prevented from being damaged by being caught by the edge portion of the outer cylinder 13. Can do. After the insertion, the catalyst 11 and the mat 12 are arranged at a substantially central position in the axial direction of the outer cylinder 13. In addition, you may comprise so that the catalyst 11 may be automatically accommodated in a desired position using the automatic insertion apparatus which is not shown in figure.

Thereafter, as shown in FIGS. 4A and 4B, the pressure detection sensor 15 is slid toward the pressure detection hole 14, and the distal end portion 15 a of the pressure detection sensor 15 is inserted into the pressure detection hole 14 of the outer cylinder 13. Then, as shown in FIG. 4B, the repulsive force of the mat 12 is detected while pressing the mat 12 with the pressure detection sensor 15.
The value of the repulsive force of the mat 12 detected by the pressure detection sensor 15 is input to the drive control unit 24 (see FIG. 5B), and the drive control unit 24 inputs the value of the repulsive force of the mat 12 thus input. Based on the above, preparation is made to perform drive control of the slider 23 in the swaging apparatus 20.
Thereafter, the outer cylinder 13 in which the catalyst 11 and the mat 12 are inserted is placed at a predetermined position of the swaging device 20, and each finger 21a of the swaging die 21 is moved to the outside as shown in FIGS. A state is brought into contact with the outer peripheral wall of the tube 13. Thereafter, drive control of the slider 23 is performed by the drive controller 24, and the slider 23 is ram-stroked by a predetermined amount. Thereby, each finger 21 a of the swaging die 21 is driven by a predetermined amount in the diameter reducing direction, and a predetermined amount of diameter reducing processing is performed by the swaging die 21 and the swaging collar 22.

  As a result, a surface pressure corresponding to the amount of diameter reduction is generated in the mat 12, and the catalyst 11 is held in a stable state in the outer cylinder 13 by a frictional force based on the surface pressure. Thereafter, the slider 23 is moved backward in the anti-ram stroke direction, the swaging die 21 is pulled out from the swaging collar 22, and the catalytic converter 10 is removed from the swaging die 21. In this manner, the diameter reduction processing based on the repulsive force when the catalyst 11 is actually mounted inside the outer cylinder 13 is performed, and the catalytic converter 10 having the predetermined gap S can be obtained.

  According to the catalytic converter 10 of the present embodiment described above, the pressure detection hole 14 for detecting the repulsive force of the mat 12 is provided on the side surface 13a of the outer cylinder 13, so that the mat is formed using the pressure detection hole 14. Twelve repulsive forces can be detected. In addition, since the pressure detection hole 14 is provided so as to face the mat 12, the repulsive force can be detected in a state where the catalyst 11 is actually mounted inside the outer cylinder 13. Accordingly, even if the dimensions of the catalyst 11 vary, it is possible to perform diameter reduction processing in accordance with the dimensions of the catalyst 11. As a result, the gap S between the catalyst 11 and the outer cylinder 13 is matched with the catalyst 11. The optimum gap S can be obtained. Thereby, the catalyst 11 can be reliably held, and the catalytic converter 10 that can withstand long-term use can be obtained.

  Further, the detection of the repulsive force of the mat 12 can be performed through the pressure detection hole 14 provided in the side surface 13a of the outer cylinder 13, and the advantage that the repulsive force can be easily detected is also obtained.

  As mentioned above, although embodiment which concerns on this invention was described, it cannot be overemphasized that this invention is not limited to these, and can change suitably according to the meaning of invention. For example, as shown in FIG. 7, the pressure detection holes 14 may be provided at a plurality of locations (three locations in the figure), and the repulsive force of the mat 12 may be detected at each of the plurality of locations. Even in this case, the repulsive force can be easily detected through a plurality of pressure detection holes 14 formed in the side surface 13 a of the outer cylinder 13. In addition, by providing the pressure detection hole 14 in the portion near the opening edge 13c of the outer cylinder 13, it becomes possible to detect the repulsive force in the relatively weak portion. It is also possible to obtain an average value of the mat 12 and use the average value as the repulsive force of the mat 12.

  In addition, as shown in FIG. 8, the pressure detection hole 14 may be provided for the bulging portion 18 that is bulged on the side surface 13 a of the outer cylinder 13. Also in such a catalytic converter 10, as shown in FIGS. 9A and 9B, the repulsive force of the mat 12 can be increased by inserting and pressing the tip 15 a of the pressure detection sensor 15 into the pressure detection hole 14. Can be detected. According to such a catalytic converter 10, since the pressure detection hole 14 is formed with respect to the bulging portion 18, the pressure detection hole 14 is inserted when the catalyst 11 wound with the mat 12 is inserted into the outer cylinder 13. There is no fear that the mat 12 will be rubbed and damaged. Therefore, the sealing performance of the mat 12 is not impaired, and an advantage that the catalyst 11 can be held in a stable state is obtained. Furthermore, in this case, as shown in FIG. 10, a seal member 16 may be provided between the mat 12 facing the pressure detection hole 14 and the outer cylinder 13.

  Furthermore, the pressure detection hole 14 may be closed by welding or the like after detecting the pressure of the mat 12.

Further, the diameter reduction processing is not limited to that performed by the swaging apparatus 20, and various methods such as spinning processing can be employed.
The diameter reduction processing may be performed several times, or may be controlled so as to be performed gradually through stages. That is, the diameter may be gradually reduced while detecting the repulsive force of the mat 12 several times.

1 is a perspective view of a catalytic converter according to an embodiment of the present invention. It is the perspective view which showed the state at the time of similarly inserting a catalyst in an outer cylinder at the time of manufacture. It is a longitudinal cross-sectional view of a catalytic converter. (A) (b) is explanatory drawing which showed the detection of the repulsive force by a pressure detection sensor. It is a figure for demonstrating diameter reduction processing at the time of manufacturing a catalytic converter, (a) is the schematic diagram which looked at the catalytic converter at the time of diameter reduction processing from the side, (b) is also a cross section around catalyst converter It is a conceptual diagram represented by. It is explanatory drawing when a sealing member is used. It is a perspective view of a catalytic converter provided with a plurality of pressure detection holes. It is a perspective view of the catalytic converter which shows another example. (A) (b) is explanatory drawing which showed the detection of the repulsive force by another example. It is explanatory drawing when a sealing member is used.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 Catalytic converter 11 Catalyst 11a Honeycomb passage 12 Mat 13 Outer cylinder 13a Side surface 14 Pressure detection hole 14a Inside hole 15 Pressure detection sensor 15a Tip 16 Seal member 20 Swaging device 21 Swaging die 21a Finger 22 Swaging collar 23 Slider 24 Drive controller S Clearance

Claims (7)

A catalytic converter in which a catalyst having a mat wound around an outer peripheral surface is inserted into an outer cylinder, and the catalyst is fixed inside the outer cylinder by the surface pressure of the mat,
A catalytic converter characterized in that a pressure detection hole for detecting a repulsive force of the mat in a state of facing the mat is provided on a side surface of the outer cylinder.   2. The catalytic converter according to claim 1, wherein the pressure detection hole is provided in a bulging portion formed to bulge on a side surface of the outer cylinder.   The catalytic converter according to claim 1, wherein a plurality of the pressure detection holes are provided.   The catalytic converter according to any one of claims 1 to 3, wherein a seal member is provided between the mat facing the pressure detection hole and the outer cylinder. A catalyst converter manufacturing method in which a catalyst having a mat wound around an outer peripheral surface is inserted into an outer cylinder, and the catalyst is fixed inside the outer cylinder by the surface pressure of the mat,
A repulsive force of the mat of the catalyst inserted into the outer cylinder is detected, and the outer cylinder is reduced in diameter so that the repulsive force becomes a predetermined repulsive force based on the detection result. A method for producing a catalytic converter, characterized by comprising:   6. The method of manufacturing a catalytic converter according to claim 5, wherein the detection of the repulsive force of the mat is performed through a pressure detection hole provided on a side surface of the outer cylinder so as to face the mat.   The said pressure detection hole is formed in multiple numbers by the side surface of the said outer cylinder, The detection of the repulsive force of the said mat | matte is performed in each of these formed pressure detection holes. Manufacturing method of the catalytic converter.

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