JP2003206734A - Manufacturing method of tandem type catalyst device and tandem type catalyst device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an easy manufacturing method with the small number of parts and a simple process, and a tandem type catalyst device. <P>SOLUTION: A forming apparatus forms a recess 3 at almost the center of a metal plate 1 having a prescribed size in a press process and has a metal roll 12 and an elastic roll 11 which contacts the metal roll 12 and has elasticity. The forming apparatus opposes the recess 3 formed in the metal plate 1 to a groove 12a of the metal roll 12, and forms a cylindrical casing D clipping and holding the metal plate 1 between each roll 11, 12. After inserting a catalyst carrier B surrounded by a mat C to the casing D, the outside diameter of the casing D is reduced and a mating part 1a is welded, and connection components E and F to an exhaust pipe are connected to both ends of the casing D so that surface pressure acting on the catalyst carrier B has a proper value. <P>COPYRIGHT: (C)2003,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a manufacturing method for preferably manufacturing a so-called tandem-type catalyst device in which at least two or more catalyst carriers are arranged in series, and a tandem-type catalyst device.

[0002]

2. Description of the Related Art In a catalyst device arranged in an exhaust system of an engine, in order to satisfy a demand for improvement of an exhaust gas purification rate, a catalyst has a large volume and a high cell size. However, since the volume of the catalyst carrier is limited due to a problem in the ceramics manufacturing method, a so-called tandem type catalyst device in which two catalyst carriers are arranged in series is provided.

In the above tandem type catalyst device, it is known that the purification efficiency is improved by making the flow of the exhaust gas into a turbulent flow between the catalyst carriers arranged in series. In addition, an intermediate spacer is arranged to change the exhaust gas from rectification to turbulent flow.

Therefore, as a tandem type catalyst device,
Forming a plurality of assemblies in which individual catalyst carriers are accommodated by applying an appropriate surface pressure through a mat, and forming an intermediate spacer provided with flange portions for welding the assemblies to both ends. Every other, place an intermediate spacer between the two assemblies, and weld them together all around to join them together.
There is a structure (first known example) in which a connecting member connected to an exhaust pipe is entirely welded to the open end side of the assembly.

Also, a tandem type catalyst device constructed by press-fitting a catalyst carrier surrounded by a non-expansion mat into both ends of a preformed cylindrical tube, and then molding the catalyst carrier so as to reduce the diameter between the catalyst carriers. (Second known example) is also provided.

[0006]

In the first known example,
When manufacturing the intermediate spacer having the flange for welding, it is necessary to go through many steps by pressing, and when the assembly containing the catalyst carrier is connected to both sides of the intermediate spacer, the intermediate spacer It is necessary to weld the flange of the spacer all around. Therefore, there is a problem that many manufacturing facilities such as a press machine and a welding device are required, and at the same time, the manufacturing process becomes long. Further, since it is composed of many parts, there is a problem that the structure of the catalyst device itself becomes complicated.

Further, in the second known example, after a plurality of catalyst carriers are press-fitted into a cylindrical pipe, the diameter of the pipe between adjacent catalyst carriers is reduced, so that the force associated with the diameter reduction causes the catalyst carrier to move. However, there is a problem in that cracks are likely to occur due to the action on the.

Further, when the diameter of the pipe is reduced, a cone portion is formed in the axial direction of the pipe. When performing this processing, it is possible to control so that the pipe and the roller for forming the cone portion are synchronized with each other. There is a problem in that the device becomes necessary and the device becomes complicated, and the contact between the tube and the roller is biased, so that the durability of the roller decreases. Further, the material in the diameter-reduced portion has a variation in wall thickness due to molding, which causes a problem in durability in a catalyst device in which cooling and heating are frequently repeated.

It is an object of the present invention to provide a tandem type catalyst device and a manufacturing method which has a small number of parts, a simple process and is easy to manufacture.

[0010]

In order to solve the above problems, a method of manufacturing a tandem type catalyst device according to the present invention manufactures a tandem type catalyst device in which a plurality of catalyst carriers are arranged in series in a metal casing. And a metal roll having a groove for receiving the recess formed in the metal plate, and a pressing step of forming a band-shaped recess in the center of the metal plate having a predetermined size. A concave portion formed on a metal plate is opposed to a groove of the metal roll, which is in contact with the elastic roll, and the metal plate is sandwiched between the metal roll and the elastic roll to form a cylindrical casing. Rolling step, an inserting step of inserting a catalyst carrier surrounded by a mat into a cylindrical casing, and a case so that the surface pressure acting on the inserted catalyst carrier has an appropriate value. The welding step of welding the mating portion by reducing the outer diameter of the ring, and the joining step of joining the connecting members with the exhaust pipe to both ends of the casing in which the mating portion is welded are included. .

In the above-described manufacturing method, a metal plate having a predetermined size is used as a material, and a press step and a roll step are performed, so that a concave groove that is convex toward the inner diameter side is formed in the central portion over the entire circumference. The casing can be configured. Then, in the insertion process, the catalyst carrier surrounded by the mats is inserted from both ends of the casing, and in the welding process, the outer diameter of the casing is reduced so that an appropriate surface pressure is applied to the catalyst carrier, and the casing is aligned. By welding the portions, at least two catalyst carriers can be held inside the casing in a state where an appropriate surface pressure is applied via the mat. Further, in the joining step, the tandem catalyst device in which a plurality of catalyst carriers are arranged in series can be manufactured by joining the connecting members connected to the exhaust pipe to both ends of the casing by means such as welding.

As described above, a continuous concave groove is formed by pressing in the substantially central portion of the metal plate, and the concave groove of the metal plate is arranged so as to be convex toward the inner diameter side and rolled. By doing so, when the cylindrical casing is molded, the convex portion formed by the concave groove exerts a function of making exhaust gas turbulent and also functions as a stopper when inserting the catalyst carrier surrounded by the mat. Can be demonstrated. Therefore, the space between the catalyst carriers can be accurately maintained, and the flow of exhaust gas can be rationally controlled.

In the above-mentioned manufacturing method, it is preferable that the pressing step includes a step of forming a curved portion at an end of a band-shaped recess formed substantially in the center of the metal plate and at a right angle to the recess. By including such a step, by forming a curved portion in a direction perpendicular to the concave groove at one end of the concave portion formed in the metal plate, the metal plate is elastic with the metal roll in the rolling step. It can be easily introduced when it is sandwiched between rolls for roll processing, or when a cylindrical casing is formed in the roll process, the mating portion can be formed into a lap joint shape.

Further, at both ends of the recess formed in the metal plate,
By forming a curved portion in the direction perpendicular to the concave groove respectively,
A metal plate is sandwiched between a metal roll and an elastic roll in the roll process to facilitate introduction when performing roll processing,
And when forming a cylindrical casing in the roll process,
The mating portion can be formed in a lap joint shape.

In particular, when the outer diameter of the casing is reduced after the catalyst carrier is inserted into the casing by forming the mating portion of the casing in the form of a lap joint,
The end surface of the casing can be slid at the overlapping portion, which is advantageous when welding the portion.

Further, in each of the above manufacturing methods, it is preferable that the elastic roll is made of urethane. By configuring the elastic roll in this way, it is possible to form a highly reliable casing without damaging the outer peripheral surface of the metal plate when rolling the metal plate.

The tandem type catalytic device according to the present invention is
A tandem type catalyst device in which a plurality of catalyst carriers are arranged in series in a metal casing, and an inner diameter smaller than the inner diameter of the accommodating portion is provided between a plurality of accommodating portions for accommodating the catalyst carrier and an adjoining accommodating portion. Arranged between a metal casing integrally formed with a small diameter portion having a metal plate and welding a plurality of accommodation portions and the small diameter portion continuously, and an inner surface of the casing accommodated in the accommodation portion of the casing. And a connecting member for connecting an exhaust pipe connected to both ends of the casing.

In the above-mentioned tandem type catalyst device (hereinafter, simply referred to as "catalyst device"), a plurality of accommodating parts for accommodating the catalyst carrier in the casing and a small diameter part formed between the adjoining accommodating parts are integrated. Since the plurality of accommodating portions and the small diameter portion are continuously welded in the axial direction, the structure of the casing can have a simple shape, and the portion to be welded is Less is all right. Therefore, it is possible to provide a rational catalyst device with reduced manufacturing cost.

In the above catalyst device, in the metal casing, the concave portion corresponding to the small diameter portion is formed over the entire circumference of the substantially middle portion, and the inclination angle of the concave portion is 40 ° to 50 °.
It is preferably in the range of degrees. By configuring the catalyst device in this way, it is possible to form a recess by pressing a metal plate prior to forming the cylindrical casing, and the recess becomes convex toward the inner diameter. By processing in this way, a small diameter portion can be formed.

In the casing having the small diameter portion,
It can function as a stopper when inserting the catalyst carrier surrounded by the mat on both sides of the small diameter portion. Therefore, the dimension between the catalyst carriers can be accurately set to rationally control the flow of exhaust gas.

[0021]

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, a method for manufacturing the above catalyst device will be specifically described, and at the same time, a structure of the catalyst device will be described. FIG. 1 is a diagram for explaining the order of steps in manufacturing a catalyst device. FIG. 2 is a diagram for explaining the metal plate when the pressing process is completed. FIG. 3 is a diagram illustrating a configuration of a roll device in a roll process. FIG. 4 is a diagram illustrating the configuration of the roll device in the roll process, and is a diagram illustrating the configuration on the opposite side of FIG. 3. FIG. 5 is a diagram illustrating the shape of the casing that has undergone the rolling process.

The method of manufacturing a catalyst device according to the present invention is as shown in FIG.
This is a method for rationally manufacturing the catalyst device A shown in FIG. 9G by sequentially performing the steps shown in FIGS.

In the catalyst device A according to the present embodiment, two catalyst carriers B each surrounded by a mat C are provided with a casing D.
Are arranged in series at both ends of the casing D and are separated from each other by a predetermined distance, and further, connecting members E and F for connecting exhaust pipes (not shown) are joined to both ends of the casing D, respectively.

The two catalyst carriers B are formed to have preset capabilities and dimensions in accordance with the specifications of the engine to which the catalyst device A is applied, and the casing D has the two catalyst carriers B appropriately. It is formed to have a size that allows it to be accommodated in a preferable state under the action of surface pressure, and to have a shape capable of changing the exhaust gas passing through the upstream catalyst carrier B from rectification to turbulent flow.

Particularly, the casing D is, as described later,
A metal plate 1 having a predetermined size is formed into a cylindrical shape by pressing and rolling, and a housing portion 2 for housing the catalyst carrier B from both ends in the longitudinal direction toward the center. And a small-diameter portion 3 which is a recess extending toward the inner diameter side between the accommodating portions 2 and approximately in the center in the longitudinal direction.
Are formed all around. For this reason, inside the casing D, an intermediate chamber 4 is formed at a portion corresponding to the small diameter portion 3.

The accommodating portion 2 is formed to have an inner diameter corresponding to the outer diameter of the catalyst carrier B and capable of exerting an appropriate surface pressure on the catalyst carrier B via the mat C. Further, the small diameter portion 3 exerts a function of making the exhaust gas flow into the downstream catalyst carrier B in a turbulent state when the exhaust gas flowing from the upstream catalyst carrier B into the intermediate chamber 4 is in a rectified state. It has an inner diameter and a length to obtain.

Particularly, the inner diameter of the small diameter portion is preferably formed to be substantially equal to or smaller than the outer diameter of the catalyst carrier B. Thus, by making the inner diameter of the small diameter portion 3 approximately equal to or smaller than the outer diameter of the catalyst carrier B, the exhaust gas in the intermediate chamber 4 surrounds the downstream catalyst carrier B in the mat C.
It is possible to prevent the mat C from being directly consumed and reduce the wear of the mat C.

The small-diameter portion 3 has two inclined portions 3a formed continuously with the accommodating portion 2 and a tubular portion 3b formed between the two inclined portions 3a. The inclination angle of the inclined portion 3a is set within the range of 40 degrees to 50 degrees. This angle range is a preferable value that allows the metal 1 to be press-formed into a recess using the manufacturing method described below without causing variation in the plate thickness.

The housing portion 2 and the small diameter portion 3 are made of one material, that is, the metal plate 1.
And the inner diameters of the accommodation portion 2 and the small diameter portion 3 are respectively set to predetermined dimensions, and then the accommodation portion 2 and the small diameter portion 3 are formed.
Are continuously welded in the axial direction and the beads 5 are welded by the welding.
Are formed.

The connecting members E and F are members for connecting to an exhaust pipe on the engine side and an exhaust pipe on the muffler side, which are not shown, and each is formed in a funnel shape, and the large-diameter portion of the funnel portion is the casing D. Are joined by being welded around the entire circumference so as to face both ends. For the shape of the connecting members E and F and the joining structure to the casing D, conventionally known means is adopted.

In the catalyst device A configured as described above, the function as a tandem type catalyst device in which two catalyst carriers B are arranged in the longitudinal direction can be exerted and high purification efficiency can be realized. In particular, the housing portion 2, in which the casing D is formed by one welding line (bead 5) formed in the axial direction,
Since the small diameter portion 3 is provided, the welding length can be shortened as compared with the conventional catalyst device, and the manufacturing cost can be reduced.

Next, a method for manufacturing the catalyst device B will be specifically described according to the order of steps shown in FIG.

FIG. 1A shows a metal plate 1, which is configured as a flat plate having a preset size. The vertical dimension (vertical dimension) of the metal plate 1 in the drawing corresponds to the lengthwise dimension of the casing D.
That is, a dimension approximately equal to the dimension obtained by adding the length of the housing portion 2 formed at both end portions of the casing D and the developed length of the small diameter portion 3 (the sum of the lengths of the two inclined portions 3a and the tubular portion 3b). have.

The lateral dimension (lateral dimension) of the metal plate 1 corresponds to the diameter of the casing D. In this embodiment, the metal plate 1 is roll-formed into a cylindrical shape having a circumference in the left-right direction, and the left-right ends are welded to form a casing D. . For this reason, it is preferable to overlap both end portions of the roll formed when the welding is performed. For this reason, at one end of the metal plate 1 in the left-right direction, a lap portion 1a having a predetermined length is formed on the outer peripheral side of the other end.

Therefore, the size of the metal plate 1 in the left-right direction is substantially equal to the sum of the outer peripheral length of the catalyst carrier B surrounded by the mat C and the length of the overlapping portion 1a. Further, the thickness is set to a value that allows the casing D of the catalyst device A to exhibit sufficient durability.

The metal plate 1 having the above-mentioned dimensions is pressed in the pressing process, and as shown in FIGS. 2B and 2, the small diameter portion of the casing D is located at the substantially vertical center. The concave portion 3 corresponding to 3 is continuously formed. Then, by forming the recess 3 substantially in the center of the metal plate 1, the portions corresponding to the housing 2 are formed on both sides of the recess 3.

A lap portion 1a having a predetermined length is provided on one end side (left side in the figure) of the metal plate 1 in the left-right direction.
A recess 6 having a step corresponding to the plate thickness of the metal plate 1 with respect to other portions and having different sizes depending on the size of the recess 3 and the plate thickness of the metal plate 1 is formed in the overlapping portion 1a. Are formed.

Further, as shown in FIG. 2, a curved portion 1b curved in the depth direction of the recess 3 is formed on the other end side (right side in the figure) of the metal plate 1 in the left-right direction. By forming the curved portion 1b, it can be smoothly introduced into a pair of rolls when performing roll forming in a roll process described later.

The recesses 3 and 6 are formed by bending the metal plate 1 and are regarded as the recesses 3 and 6 when viewed from one surface (the outer peripheral surface of the casing D). However, when viewed from the other surface (the surface on the inner peripheral side of the casing D), it is recognized as a convex portion. In addition, the concave portion 3
The inclined portion 3a is formed at an angle in the range of 40 degrees to 50 degrees, and the accommodation portion 2 is formed by forming the angle in this range.
It is possible to form a favorable concave portion 3 (small-diameter portion 3) without changing the wall thickness in the molded portion from the cylindrical portion 3b to the cylindrical portion 3b.

FIG. 6C is a diagram for explaining the roll process, which is a process of roll-forming the metal plate 1 that has undergone the pressing process into a cylindrical shape with the tubular portion 3b of the recess 3 inside. This roll process has a roll forming device shown in FIGS. 3 and 4, and the metal plate 1 is passed through the roll forming device to form a roll, as shown in FIG. 1 (d) and FIG. It is possible to form a simple cylindrical casing D.

First, the structure of the roll forming apparatus will be described. It should be noted that this roll forming apparatus is an example that can be suitably used when rolling the metal plate 1, and does not limit the configuration of the roll step when carrying out the present method.

The roll forming apparatus comprises an elastic roll 11 having elasticity, a metal roll 12 which is in contact with the elastic roll 11 and has a groove 12a for receiving the concave portion 3 formed in the metal plate 1 at substantially the center, and the elastic roll 11. The backup roll 13 disposed on the downstream side in the transport direction of the metal plate 1 (downstream side in the arrow direction) accompanying the rotation of the metal roll 12 and the metal roll 12 and the elastic roll 11
And a biasing roll 14 that biases the side.

A urethane layer is formed on the surface of the elastic roll 11, and elasticity is imparted by the urethane layer. The elastic roll 11 has a diameter sufficiently larger than that of the metal roll 12 and is rotationally driven in the arrow direction by a driving device (not shown). Therefore, when the elastic roll 11 rotates, the metal roll 12 that is in contact with the elastic roll 11 is driven to rotate, or the metal plate 1 is sandwiched between the metal roll 12 and the metal roll 12, and the metal roll 1 is sandwiched between the metal roll 1 and the metal roll 1. The rotation is transmitted to 12. In particular, since the elastic roll 11 has elasticity, it is possible to realize good molding without damaging the metal plate 1 sandwiched between the elastic roll 11 and the metal roll 12.

The metal roll 12 is a casing D to be molded.
Is formed with a diameter smaller than that of the metal plate 1, at a position substantially in the center and facing the concave portion 3 formed in the metal plate 1.
The groove 12a is formed. The groove 12a is a recess 3 formed on one surface of the metal plate 1 (surface on the outer surface of the casing D).
Accepts a chevron-shaped projection formed on the other surface (the inner surface of the casing D).

The metal roll 12 is configured to be biased toward the elastic roll 11 side by the biasing roll 14 and released from the biasing force. That is, the urging roll 14 is rotatably mounted on the frame 14a, and the frame 14a is configured to be vertically movable and urged by a driving device (not shown). Then, by moving the frame 14a downward and urging the metal roll 12 toward the elastic roll 11 with a preset force, the metal roll 12 is moved.
To the frame 14 with a substantially constant force.
By moving a upward, the contact of the metal roll 12 with the elastic roll 11 can be released and the metal roll 12 can be separated from the elastic roll 11.

The backup roll 13 is transported by being sandwiched between the metal roll 12 and the elastic roll 11, and in this process, urges the metal plate 1 curved to the metal roll 12 side so as to be further pressed against the metal roll 12 side. The metal plate 1 that has passed through the contact portion between the metal roll 12 and the elastic roll 11 is further urged by the backup roll 13 to be roll-formed into a cylindrical shape corresponding to the casing D.

Therefore, the metal plate 1 that has undergone the pressing process has the curved portion 1b as a leading portion and the concave portion 3 is laid down and the concave portion 3 is formed.
When the protrusions corresponding to the rolls 11 are opposed to the groove 12a of the metal roll 12 and transferred in this state between the rotating elastic roll 11 and the metal roll 12, the metal plate 1 sandwiched between the rolls 11 and 12 bends the curved portion 1b. Passes and is further urged toward the metal roll 12 side by the backup roll 13 to be molded.

The overlapping portion 1a of the metal plate 1 is a metal roll.
When passing between 12 and backup roll 13,
The metal plate 1 is formed in a state in which the overlapping portion 1a is overlapped on the outer peripheral side of the curved portion 1b with the concave portions 3 and 6 aligned with each other.

A jig having a cross-sectional shape substantially equal to the shape of the concave portion 3 composed of the two inclined portions 3a and the cylindrical portion 3b is formed, and the jig is fitted into the concave portion 3 during the roll forming. It is also possible to pass the metal plate 1 between the rolls 11 to 13. In this case, the recess 3 can be restrained during roll forming of the metal plate 1 to realize highly accurate forming.

By undergoing the roll forming process as described above, it is possible to form the casing D as shown in FIG. 1 (d). The casing D is open at both end portions, and the housing portion 2 extends from the both end portions to the central portion.
Is formed, and the small-diameter portion 3 is formed between the accommodating portions 2. In the casing D shown in the drawing, the overlapping portion 1a is not welded yet, and therefore the inner diameters of the housing portion 2 and the small diameter portion 3 can be changed.

Next, as shown in FIG. 1 (e), the catalyst carrier B surrounded by the mat C in the accommodating portion 2 of the casing D, respectively.
Insert. As the mat C, a non-expansion type is used, and the mat C surrounds the outer periphery of the catalyst carrier B by wrapping it. When the catalyst carrier B surrounded by the mat C is inserted into the housing portion 2 of the casing D, no surface pressure is applied to the catalyst carrier B, or an extremely small surface pressure is applied.

Further, as shown in (f) of the same figure, after the catalyst carriers B surrounded by the mat C are housed in the respective housing portions 2, a force in the diameter reducing direction is applied to the outer periphery of the casing D so that the mat C and the catalyst carrier B are tightened, so that an appropriate surface pressure is applied to the catalyst carrier B. Then, when an appropriate surface pressure is applied to the catalyst carrier B, the tightened state with respect to the casing D is maintained, and the overlapping portion of the overlapping portion 1a and the metal plate 1 is changed from the accommodating portion 2 on one side to the small diameter portion 3 and the other side. Housing part 2
Fillet welds continuously over, which results in beads 5
To restrain the shape of the casing D. In this state, the casing D holds the catalyst carrier B on both ends by applying appropriate surface pressure via the mats C, and the intermediate chamber 4 corresponding to the small diameter portion 3 is formed between the catalyst carriers B. It

Next, as shown in FIG. 3G, the connecting members E and F are opposed to and abutted on both end portions of the casing D in which the catalyst carrier B is accommodated through the mat C in each accommodating portion 2. Then, the catalyst device A can be manufactured by welding the entire abutting portions to join them.

As described above, in the pressing step, the concave portions 3 are press-molded in the single metal plate 1 to form the accommodating portions 2 for the catalyst carrier B on both sides of the concave portion 3, and further, this metal is used. Elastic roll 11 and metal roll 12 are used in the roll forming process of plate 1.
It is inserted into rolls and rolled to form a cylindrical casing D
Can be formed. Therefore, by manufacturing the casing D having the two accommodating portions 2 from the single metal plate 1, the accommodating portions 2 and the small diameter portion 3 are integrally and continuously formed. It becomes possible to rationalize.

In this embodiment, the case where the two accommodating portions 2 are formed in the metal plate 1 has been described. However, by forming two or more concave portions 3, the concave portions 3 are accommodated on both sides of each concave portion 3. It is possible to form part 2 and therefore 3
It is possible to form a casing D capable of accommodating one or more catalyst carriers B. In this case, when the catalyst carrier B surrounded by the mat C is inserted into the housing portion 2, the casing D
It is possible to work relatively easily by slightly expanding the diameter of the.

After accommodating the catalyst carriers B surrounded by the mat C in three or more accommodating portions 2 formed in the casing D, the casing D is tightened as in this embodiment so that each catalyst carrier B can be properly accommodated. It is possible to manufacture the catalyst device A containing three or more catalyst carriers B by applying a specific surface pressure and welding the overlapped portion 1a while maintaining this state.
That is, it becomes possible to manufacture the tandem type catalyst device A in which two or more catalyst carriers B are arranged in series including the present embodiment.

[0057]

As described in detail above, in the tandem-type catalyst device manufacturing apparatus according to the present invention, a metal plate having a predetermined size is subjected to a pressing process and a rolling process so that a small diameter portion is formed in the central portion. It is possible to configure a cylindrical casing in which the catalyst carrier accommodating portions are formed on both sides of the small diameter portion. Then, by passing through the inserting step, the welding step, and the joining step, it is possible to manufacture a tandem type catalyst device in which a plurality of catalyst carriers to which an appropriate surface pressure is applied are arranged in series.

In particular, in the pressing step, by forming a curved portion at the end of the concave portion at a right angle to the concave portion, it is advantageous when the metal plate is sandwiched between the metal roll and the elastic roll, and it is cylindrical. When the casing is molded, the mating portion can be formed into a lap joint shape. In this way, by forming the lap joint in the casing in a lap joint shape, it is possible to slide the end surface of the casing at the lap when the outer diameter of the casing in which the catalyst carrier is inserted is reduced. Which is advantageous when welding the part.

Further, since the elastic roll is made of urethane, it is possible to form a highly reliable casing without damaging the outer peripheral surface of the metal plate when rolling the metal plate.

Further, in the catalyst device according to the present invention, the plurality of accommodating portions formed in the casing and the small diameter portion formed between the adjoining accommodating portions are integrally formed of the metal plate, and Since the housing part and the small diameter part are continuously welded in the axial direction, the structure of the casing can be made into a simple shape, the number of parts can be reduced, and the number of parts to be welded is small. good. Therefore, it is possible to provide a rational catalyst device with reduced manufacturing cost.

By setting the inclination angle of the small diameter portion formed in the casing within the range of 40 to 50 degrees, the small diameter portion serves as a stopper when the catalyst carrier surrounded by the mat is inserted on both sides of the small diameter portion. The function can be exhibited, and the dimension between the catalyst carriers can be accurately set to rationally control the flow of exhaust gas. Also, the small diameter portion can be rationally molded without variation in wall thickness.

[Brief description of drawings]

FIG. 1 is a diagram illustrating the order of steps in manufacturing a catalyst device.

FIG. 2 is a diagram illustrating a metal plate when a pressing process is completed.

FIG. 3 is a diagram illustrating a configuration of a roll device in a roll process.

FIG. 4 is a diagram illustrating a configuration of a roll device in a roll process, which is a diagram illustrating a configuration on the opposite side of FIG. 3.

FIG. 5 is a diagram illustrating a shape of a casing that has undergone a rolling process.

[Explanation of symbols]

A catalyst device B catalyst carrier C mat D casing E, F connecting member 1 metal plate 1a Overlap part 1b curved part 2 accommodation 3 Small diameter part 3a inclined part 3b tube 4 Intermediate room 5 beads 6 recess 11 Elastic roll 12 metal roll 12a groove 13 Backup roll 14 bias roll 14a frame

─────────────────────────────────────────────────── ─── Continuation of front page (51) Int.Cl. ⁷ Identification code FI theme code (reference) B21D 5/14 B21D 5/14 A 35/00 35/00 51/18 51/18 B 53/84 ZAB 53 / 84 ZABB F01N 3/24 F01N 3/24 C F term (reference) 3G091 AB01 BA09 GA02 HA08 HA27 HA47 4E063 AA01 BB01 EA04 MA01

Claims (5)

[Claims] 1. A method for manufacturing a tandem type catalyst device in which a plurality of catalyst carriers are arranged in series in a metal casing, wherein a band-shaped recess is formed at a substantially center of a metal plate having a predetermined size. And a recess formed in the metal plate in the groove of the metal roll, which has a metal roll having a groove for receiving the recess formed in the metal plate and an elastic roll contacting the metal roll and having elasticity. And a roll step of sandwiching the metal plate between a metal roll and an elastic roll to form a cylindrical casing, and inserting a catalyst carrier surrounded by a mat into the cylindrical casing. Both the process, the welding process of welding the mating part by reducing the outer diameter of the casing so that the surface pressure acting on the inserted catalyst carrier has an appropriate value, and the casing in which the mating part is welded. A joining step of joining a connecting member to an exhaust pipe at an end thereof, the method for producing a tandem catalyst device. 2. The pressing step includes a step of forming a curved portion at an end of a band-shaped recess formed substantially in the center of a metal plate and at a right angle to the recess.
A method for manufacturing the tandem type catalyst device described in 1. 3. The method for manufacturing a tandem catalyst device according to claim 1, wherein the elastic roll is made of urethane. 4. A tandem-type catalyst device in which a plurality of catalyst carriers are arranged in series in a metal casing, wherein an inner diameter of the plurality of housing units for housing the catalyst carriers and an adjacent housing unit are provided between the housing units. A casing made of metal in which a small-diameter portion having an inner diameter smaller than that of the metal plate is integrally formed, and a plurality of accommodating portions and the small-diameter portion are continuously welded; and an inner surface of the casing accommodated in the accommodating portion of the casing. A tandem type catalyst device comprising: a catalyst carrier having a mat disposed between the casing and a connecting member for connecting exhaust pipes connected to both ends of the casing. 5. The metal casing is characterized in that a concave portion corresponding to the small diameter portion is formed over the entire circumference of a substantially middle portion, and the inclination angle of the concave portion is in the range of 40 degrees to 50 degrees. The tandem-type catalyst device according to claim 4.