JP2005171830A - Manufacturing method of catalytic converter - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a manufacturing method of a catalytic converter for disposing a catalyst and an outer cylinder with a suitable space therebetween and thereby to stably hold the catalyst. <P>SOLUTION: In the manufacturing method of a catalytic converter, the converter 11 around which a mat 12 is wound is inserted into the outer cylinder 13, and a diameter of the outer cylinder 13 is reduced to fix the catalyst 11 through the mat 12. With the catalyst 11 inserted into the outer cylinder 13, the space S between an outer circumferential face 11b of the catalyst 11 and an inner wall face 13b of the outer cylinder 13 is measured, a diameter reduction processing amount of the outer cylinder 13 is adjusted so that the space S becomes a predetermined space S based on the measurement result. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a method for manufacturing a catalytic converter capable of holding a catalyst in a stable state.

2. Description of the Related Art Conventionally, a catalytic converter for purifying exhaust gas is provided in an exhaust system of various engines including an automobile engine. 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 thickness of the mat (hereinafter referred to as a gap) interposed between the catalyst and the outer cylinder be uniform. Here, if the gap between the catalyst and the outer cylinder varies, the sealing performance may be hindered or the elastic holding force may vary, which may damage the catalyst. It becomes difficult to maintain. 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.
Japanese Patent Laying-Open No. 2001-263052 (paragraphs 0019 to 0020, FIG. 2)

  As a method for making the gap between the catalyst and the outer cylinder uniform, conventionally, the outer diameter is measured by directly applying a measuring instrument or the like to the outer cylinder or the catalyst, and an appropriate reduced diameter derived from the measured value. The gap between the catalyst and the outer cylinder was managed by performing a diameter reduction operation by obtaining the amount. However, since the catalyst originally has a variation in diameter and also has a twist, a bend, etc., in the manufacturing method in which the diameter is uniformly reduced from the measured value of the outer diameter of the outer cylinder or the like as described above, There is a problem that it is difficult to form an appropriate gap with the outer cylinder, and the catalyst cannot be stably held in the outer cylinder.

  Accordingly, an object of the present invention is to provide a method of manufacturing 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.

  In the method of manufacturing a catalytic converter according to claim 1 of the present invention that has solved the above-mentioned problems, a catalyst having a mat wound around its outer peripheral surface is inserted into the outer cylinder, and the outer cylinder is reduced in diameter. A method of manufacturing a catalytic converter in which the catalyst is fixed to the inside of the outer cylinder through the mat, and the outer peripheral surface of the catalyst and the catalyst are inserted in the outer cylinder. A gap with the inner wall surface of the outer cylinder is measured, and the diameter reduction processing amount of the outer cylinder is adjusted so that the gap becomes a predetermined gap based on the measurement result.

  According to the first aspect of the present invention, the gap between the outer peripheral surface of the catalyst and the inner wall surface of the outer cylinder is measured in a state where the catalyst is inserted into the outer cylinder, and based on the measurement result, the outer cylinder The amount of diameter reduction processing is adjusted. That is, the measurement of the gap between the outer peripheral surface of the catalyst and the inner wall surface of the outer cylinder is measured in a mounted state in which the catalyst is inserted into the outer cylinder, and the adjustment of the diameter reduction processing amount is actually measured. This is performed based on the gap. As a result, even if the dimensions of the catalyst vary, it is possible to reduce the diameter in accordance with the size of the catalyst. As a result, the gap between the catalyst and the outer cylinder is adjusted to the optimum gap according to the catalyst. can do. Therefore, the catalyst can be reliably held in a stable state, and a catalytic converter that can withstand long-term use can be obtained.

  In addition, since the amount of diameter reduction processing is adjusted by measuring the actual gap, the amount of diameter reduction is indirectly measured by measuring the outer diameter of the outer cylinder and the outer diameter of the catalyst as in the past. In contrast to performing the reduction in diameter, an optimal gap can be secured. Therefore, a catalytic converter capable of maintaining stable retention of the catalyst over a long period of time is obtained.

  According to a second aspect of the present invention, in the method for manufacturing a catalytic converter according to the first aspect, the measurement of the gap is performed by processing an image captured by a recognition camera arranged at least on the side of the gap. It is performed.

  According to the second aspect of the present invention, the gap between the outer peripheral surface of the catalyst and the inner wall surface of the outer cylinder is captured as an image by the recognition camera disposed on the side, and the measurement of the gap processes the image. Therefore, unlike the conventional method of measuring the outer diameter of an outer cylinder, there is no complication of making a measurement by directly applying a measuring instrument to the outer cylinder, and high-precision gap measurement is easily performed. The advantage that it can be obtained.

  According to a third aspect of the present invention, in the method for producing a catalytic converter according to the first or second aspect, the diameter reduction processing is performed while measuring the gap.

  According to the invention described in claim 3, since the diameter reduction processing is performed while the gap is measured, the gap measurement operation and the diameter reduction operation are continuously performed in one work process. be able to. Therefore, the process can be shortened, the productivity can be improved, and the cost can be reduced. Further, since it is not necessary to move the outer cylinder into which the catalyst is inserted after the measurement operation, the measurement accuracy is ensured, and highly accurate diameter reduction processing can be realized. Therefore, a high quality catalytic converter can be obtained.

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

  Hereinafter, with reference to drawings, the manufacturing method of the catalytic converter concerning the embodiment of the present invention is explained.

  In the drawings to be referred to, FIG. 1 is a perspective view of a catalytic converter manufactured by a method for manufacturing a catalytic converter according to an embodiment of the present invention, and FIG. 2 shows a state when the catalyst is inserted into an outer cylinder during the manufacturing process. The perspective view shown and FIG. 3 are longitudinal sectional views of the 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 conical exhaust passage (not shown) is integrally formed by welding or the like in the front and rear portions of the outer cylinder 13.

  4A and 4B are diagrams for explaining the diameter reduction processing when manufacturing such a catalytic converter 10, wherein FIG. 4A is a schematic view of the catalytic converter viewed from the side during the diameter reduction processing, and FIG. 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. Moreover, the swaging apparatus 20 has the measuring apparatus 30 for measuring the clearance gap S between the outer peripheral surface 11b of the catalyst 11, and the inner wall face 13b of the outer cylinder 13, as shown to Fig.4 (a). The adjustment of the diameter reduction processing amount is performed based on the measurement result by measuring the gap S in the mounted state in which the catalyst 11 is inserted into the outer cylinder 13 by the measuring device 30.

Hereinafter, each part will be described. As shown in FIG. 4A, the swaging device 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. 4 and a slider 23 for causing the swaging die 21 to make a ram stroke, as shown in FIG. 4B.
In the swaging die 21, the sliding contact surface 21b of each finger 21a with respect to the swaging collar 22 is formed in a downwardly inclined manner in the ram stroke direction of the swaging die 21 (arrow A direction in FIG. 4B: 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 (in the direction of arrow B in FIG. 4A). 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.

  As shown in FIG. 4B, the measuring device 30 includes two cameras (recognition cameras) C1 and C2, an image processing unit 31 that processes images captured by the cameras C1 and C2, and the image processing unit. A clearance calculation unit 32 that calculates an average value S1 of the clearance S from the image processed by the image 31 and a diameter reduction processing amount calculation unit 33 that calculates a diameter reduction processing amount from the average value S1 calculated by the clearance calculation unit 32. And a drive control unit 34 that controls the drive of the slider 23 of the swaging apparatus 20.

  The cameras C1 and C2 have an image pickup device capable of performing photoelectric conversion such as a CCD (Charge Coupled Device), and are disposed to face predetermined positions on both sides of the catalytic converter 10. The cameras C1 and C2 are provided with wide-angle lenses, and the entire sides of the catalytic converter 10 can be photographed at a time. Images captured by the cameras C1 and C2 are sent to the image processing unit 31 as image signals.

  The image processing unit 31 takes in the image signals from the cameras C1 and C2, and performs binarization processing for binarizing the image density (256 gradations) into black and white for each image signal. And the boundary part (The outer peripheral surface 11b of the catalyst 11, The inner wall surface 13b of the outer cylinder 13) is discriminate | determined from the processed data. Here, in the images photographed by the cameras C1 and C2, the catalyst 11 appears dark, the mat 12 appears slightly bright, and the outer cylinder 13 appears brighter. Therefore, in such an image, it is possible to clearly discriminate each boundary portion (the outer peripheral surface 11b of the catalyst 11 and the inner wall surface 13b of the outer cylinder 13) by setting a threshold value for distinguishing these. The image processing unit 31 has an image memory for temporarily storing images input from the cameras C1 and C2.

  The gap calculation unit 32 calculates the values of the respective gaps S at four points on the upper and lower and left and right sides of the catalytic converter 10 and a total of eight points on both sides based on the position information of the boundary portion determined by the image processing unit 31. To do. Then, the gap calculation unit 32 calculates an average value S1 from the calculated values of the gaps S. Here, the calculated average value S1 is assumed to be the gap S of the catalytic converter 10 before the diameter reduction processing.

  The diameter reduction processing amount calculation unit 33 has a predetermined value (design value) S2 of the gap S input in advance by a keyboard (not shown) or the like, and the predetermined value S2 and the average value calculated by the gap calculation unit 32 The difference is obtained by comparing with S1, and the diameter reduction processing amount (specifically, the ram stroke drive amount of the swaging die 21) is calculated so that the clearance S of the catalytic converter 10 becomes the predetermined value S2. It has become. Here, it is desirable that the predetermined value S2 of the gap S is set in consideration of the strength and the outer diameter of the material of the catalyst 11, and the elasticity and thickness of the material of the mat 12. In the present embodiment, the predetermined value S2 (design value) of the gap S is set to 3.6 mm ± 0.3 mm.

  The diameter reduction processing amount can be calculated as a value in consideration of the influence of the springback of the outer cylinder 13 while avoiding the risk of damage to the catalyst 11 and the collapse of the mat 12 by conducting experiments and the like in advance. .

The drive control unit 34 receives data of the diameter reduction processing amount calculated by the diameter reduction processing amount calculation unit 33, and controls the ram stroke of the slider 23 based on the data. When the ram stroke of the slider 23 is controlled by the drive control unit 34, the swaging die 21 is driven in the diameter reduction direction, and as a result, the catalytic converter 10 is reduced in diameter by a desired diameter reduction processing amount. It is processed to the state.
Further, the drive control unit 34 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, a method for manufacturing a catalytic converter using such a swaging apparatus 20 will be described. 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).
At this time, the mat 12 may be configured in such a manner that convex portions and concave portions (not shown) that engage with each other are formed in both end portions in advance and are wound so as to engage with each other during winding. . 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.

  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 15 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, the outer cylinder 13 in which the catalyst 11 and the mat 12 are inserted is disposed 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. 4 (a) and 4 (b). Preparation for diameter reduction processing described later is performed so as to be in contact with the outer peripheral wall of the cylinder 13.

Here, the operation of the measuring apparatus 30 will be described with reference to the flowchart of FIG.
First, in step ST1, the two cameras C1 and C2 are used to photograph both sides of the outer cylinder 13 (catalytic converter 10 before diameter reduction), and an image for measuring the gap S is acquired. Thereafter, in step ST2, the image processing unit 31 performs a binarization process for binarizing the shades of the images captured by the cameras C1 and C2 into black and white, and a boundary for specifying the gap S from the processed data. The part (the outer peripheral surface 11b of the catalyst 11 and the inner wall surface 13b of the outer cylinder 13) is discriminated. Thereafter, in step ST3, the gap calculation unit 32 obtains the position information of the boundary portion determined in step ST2, and calculates the gap S based on the position information. The clearance S is calculated for a total of 8 points on the upper and lower sides and the left and right sides of the catalytic converter 10. Then, an average value S1 is calculated from the calculated values of the gaps S.

  Thereafter, in step ST4, the diameter reduction processing amount calculation unit 33 obtains a difference between the average value S1 of the gap S calculated in step ST3 and a predetermined value S2 (design value), and reduces the predetermined value S2. The diameter machining amount is calculated. In step ST5, the drive control unit 34 controls the ram stroke of the slider 23 (see FIG. 4B) based on the diameter reduction amount data calculated in step ST4. A predetermined amount of diameter reduction processing is performed with the ging collar 22. As a result, a surface pressure corresponding to the amount of diameter reduction is generated, and the catalyst 11 and the mat 12 are 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. Thereby, the catalytic converter 10 in which the gap S is set to the predetermined value S2 can be obtained.

  According to the manufacturing method of the catalytic converter of the present embodiment described above, the gap S (average value S1) is measured with the catalyst 11 and the mat 12 mounted on the outer cylinder 13, as shown in FIG. Since the amount of diameter reduction processing is adjusted (calculated and diameter reduction processing) based on the measured gap S, diameter reduction processing corresponding to the gap S can be performed. As a result, 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, and as a result, the gap S between the catalyst 11 and the outer cylinder 13 is formed in the catalyst 11. The optimum gap S can be obtained. Therefore, the catalyst 11 can be reliably held, and the catalytic converter 10 that can withstand long-term use can be obtained.

  In addition, since the amount of diameter reduction processing is adjusted by measuring the actual gap S, the outer diameter of the outer cylinder 13 and the outer diameter of the catalyst 11 are measured indirectly as in the prior art. Unlike the case where the diameter is reduced and the diameter is reduced, the optimum gap S can be secured. Therefore, it is possible to obtain a catalytic converter 10 that can realize stable retention of the catalyst 11 for a long period of time.

  In addition, the gap S is captured as an image by the two cameras C1 and C2 arranged on the sides, and the measurement of the gap S is performed by processing the image. Therefore, the outer diameter of the conventional outer cylinder is reduced. Unlike the case of measuring, there is no trouble that the measurement device is directly applied to the outer cylinder, and there is an advantage that the high-accuracy clearance S can be easily measured.

  Furthermore, according to the manufacturing method of the catalytic converter 10 of the present embodiment, the measurement operation of the gap S and the diameter reduction processing operation can be continuously performed in one operation process. Therefore, the process can be shortened, the productivity can be improved, and the cost can be reduced. In addition, since it is not necessary to move the outer cylinder 13 in which the catalyst 11 is inserted to the diameter reduction processing place after performing the measurement work, the measurement accuracy is ensured and the diameter reduction processing with high accuracy can be realized. it can. Therefore, a high quality catalytic converter 10 can be 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 main point of invention. For example, it may be configured such that the shooting direction of the cameras C1 and C2 can be adjusted using a position adjusting pulse motor or the like (not shown). Alternatively, a small CCD camera or the like may be arranged in advance for each of the eight points in total, and an image at each point may be captured by these CCD cameras. In this case, since the video of each point can be captured independently by each CCD camera, it is possible to calculate the gap S with higher certainty, and the catalyst 11 is held in a more stable state. .

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 measuring the gap S.

It is a perspective view of the catalytic converter manufactured with the manufacturing method of the catalytic converter which concerns on one embodiment of this 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. 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 a flowchart for demonstrating the effect | action in a measuring apparatus.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 Catalytic converter 11 Catalyst 11a Honeycomb passage 11b Outer peripheral surface 12 Mat 13 Outer cylinder 13b Inner wall surface 20 Swaging device 21 Swaging die 21a Finger 22 Swaging color 23 Slider 30 Measuring device 31 Image processing part 32 Gap calculation part 33 Reduced diameter Machining amount calculation unit 34 Drive control unit C1, C2 Camera S Clearance

Claims (3)

A catalytic converter in which a catalyst having a mat wound around its outer peripheral surface is inserted into the outer cylinder, and the outer cylinder is reduced in diameter so that the catalyst is fixed inside the outer cylinder via the mat. A manufacturing method of
With the catalyst inserted into the outer cylinder, the gap between the outer peripheral surface of the catalyst and the inner wall surface of the outer cylinder is measured, and the gap becomes a predetermined gap based on the measurement result. A method for manufacturing a catalytic converter, characterized in that the diameter reduction processing amount of the outer cylinder is adjusted.   The method for manufacturing a catalytic converter according to claim 1, wherein the measurement of the gap is performed by processing an image captured by a recognition camera arranged at least on the side of the gap.   The method for manufacturing a catalytic converter according to claim 1, wherein the diameter reduction processing is performed while measuring the gap.

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