JP2003074336A - Exhaust emission control device and method of manufacturing the control device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To assure a sufficient surface pressure necessary for stably maintaining a purification unit while avoiding the risk of damage to the purification unit and of rupture of a mat in an exhaust emission control device adopting an insert type metal shell structure. SOLUTION: A catalytic converter as this exhaust emission control device comprises a metal shell 1, a catalytic carrier 2 as the purification unit, and the mat 3 disposed between both thereof 1 and 2. In this catalytic converter, after the catalytic carrier 2 having the mat 3 wound thereon is inserted into the cylindrical metal shell 1, the outer peripheral surface of the metal shell 1 is uniformly pressurized in radial inner direction with the metal shell 1 heated by using a chuck mechanism 10 with a heating means 12 to compress the metal shell 1 to a target diameter smaller than the initial diameter thereof so as to stably hold the catalytic carrier 2 and the mat 3 in the metal shell 1.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an exhaust gas purifying apparatus represented by a catalytic converter and the like, and a manufacturing method thereof.

[0002]

2. Description of the Related Art Generally, a catalytic converter for purifying exhaust gas is provided in an exhaust path of a gasoline engine for a vehicle. This catalytic converter is composed of a metal shell (case) that defines a cylindrical storage space, a cylindrical ceramic catalyst carrier carrying a NOx reduction catalyst, etc., and a mat (for example, inorganic fiber) wound around the catalyst carrier. (Filler consisting of a sheet). The mat is interposed between the outer peripheral surface of the catalyst carrier and the inner peripheral surface of the metal shell to prevent exhaust gas from leaking through the gap between the inner and outer peripheral surfaces, and to exert a pressing force (contact pressure) on the inner and outer peripheral surfaces. ) Is used to stably hold the catalyst carrier in the metal shell.

Clam shell type, turnnikit type and insertion type (also referred to as press-fitting type) are known as the configuration of the metal shell in the catalytic converter. In the clamshell type, the metal shell is divided into upper and lower halves, and the catalyst carrier around which the mat is wrapped is sandwiched between the two pieces to join the two pieces, but the packing density of the mat is uneven. However, there is a defect that the surface pressure distribution becomes non-uniform due to the occurrence of.

In the Thani kit type, a catalyst carrier having a mat wound is placed in a roll body obtained by roll-forming a metal plate in advance into a cylindrical shape, and then the roll body is clamped in the circumferential direction and then the side edges are weld-bonded to each other. It is a thing. The Thani kit type has been considered a rational method because it can flexibly respond to changes in the diameter of the catalyst support and can even out the surface pressure distribution. However, the Thani kit type has a drawback in that, when the side edges of the roll-formed metal plates are welded to each other, the mat is damaged by the burn-through of the metal. Further, it is difficult to apply a spinning process when a desired drawing shape is applied to the front and rear openings of the cylindrical metal shell after holding the catalyst carrier in the metal shell. Therefore, there is no choice but to join the members in a welded manner to form the shape of the front and rear openings of the shell.
It was difficult to reduce the total manufacturing cost. Therefore,
The insertion shell is becoming the mainstream for the metal shell of a catalytic converter.

In the insertion type (press-fitting type), a metal shell is formed in advance as a cylinder having a predetermined diameter, and a catalyst carrier around which a mat is wound is inserted into the cylinder. In order to secure the surface pressure for holding the catalyst carrier in the shell, while inserting the mat wrapped around the catalyst carrier into the cylindrical shell while compressing, or after inserting the catalyst carrier wrapped with the mat into the cylindrical shell, The shell is reduced in diameter by applying pressure in the direction of diameter reduction over the entire circumference of the shell. According to the insertion type, not only the surface pressure distribution can be made uniform, but also the front and rear openings of the metal shell can be subjected to a spinning process afterwards.

[0006]

Although it has been stated that the mat wound around the catalyst carrier is compressed when the catalyst carrier is inserted into the insertion type metal shell, the initial inner radius of the shell and the outer radius of the catalyst carrier are described. If the thickness of the mat is much larger than the difference (gap), it will be necessary to force the mat to be compressed during insertion, resulting in an excessive increase in surface pressure during the insertion process (and eventually damage to the catalyst carrier or crush of the mat). It can happen. Therefore, the thickness of the mat has to be limited to the above-mentioned gap, and there is not much freedom in setting the thickness of the mat. Therefore, securing the surface pressure for stably holding the catalyst carrier in the shell depends mainly on the diameter reduction processing of the metal shell after inserting the catalyst carrier wound with the mat into the shell.

However, there is a problem in this diameter reduction processing. This is because even if the cylindrical metal shell is to be uniformly pressed in the diameter-reducing direction over its entire circumference to deform it to the desired diameter-reduced state, when the pressure is released, the diameter is restored by the metal's original repulsion elasticity. A phenomenon (called springback) that tries to (enlarge) occurs. Therefore, it is necessary to determine the amount of diameter reduction due to pressurization in consideration of the amount of diameter expansion due to springback in advance. For example, as shown in FIG. 7, when it is desired to reduce the diameter of the cylindrical metal shell having the initial inner radius R1 to the target inner radius R2, the spring back amount ΔR at the time of releasing the pressure is taken into consideration and the inner radius becomes R3. It was necessary to apply directional pressure.

However, even if the inner diameter of the metal shell is temporarily reduced to R3, it means that the surface pressure rise corresponding to the state of the inner diameter R3 is induced, and the catalyst carrier is damaged by the excessive surface pressure rise. The risk of crushing mats and mats increases. On the other hand, in order to avoid such a danger, there is no choice but to keep the minimum reachable diameter R3 at the time of radial pressurization within the safety range.
The inner radius R2 'of the shell after the pressure is released becomes larger than the target inner radius R2, which may lead to insufficient holding force due to a decrease in surface pressure. In other words, in the conventional processing technique, it is possible to avoid both the risk of catalyst carrier damage and mat crushing in the compression processing stage, and to ensure a sufficient surface pressure necessary for stable retention of the catalyst carrier. It was very difficult.

An object of the present invention is to stabilize the catalyst carrier (purification unit) while avoiding the risk of damage to the catalyst carrier (purification unit) and crushing of the mat in an exhaust gas purification device adopting an insertion type metal shell structure. An object of the present invention is to provide an exhaust gas purifying device capable of ensuring a necessary and sufficient surface pressure for holding. Another object of the present invention is to provide a method for manufacturing an exhaust gas purification device that can reliably obtain such an exhaust gas purification device.

[0010]

According to a first aspect of the present invention, there is provided a metal shell for partitioning a substantially cylindrical storage space, a substantially columnar purification unit installed in the storage space, and the metal shell. An exhaust gas purifying apparatus comprising a mat interposed between the purifying unit and a cylindrical metal shell, wherein a substantially columnar purifying unit in which the mat is wound is inserted, and then the metal shell is heated. By uniformly pressing the outer peripheral surface of the metal shell in the diameter reducing direction, the metal shell is compressed to a target diameter smaller than the initial diameter and the mat and the purification unit are held in the cylindrical metal shell. It is an exhaust gas purification device that does.

According to a second aspect of the present invention, there is provided a metal shell defining a substantially cylindrical storage space, a substantially columnar purification unit installed in the storage space, and a space between the metal shell and the purification unit. A method of manufacturing an exhaust gas purifying apparatus comprising a mat interposed in a cylindrical metal shell,
An insertion step of inserting a substantially columnar purification unit around which a mat is wound, and a metal shell containing the mat and the purification unit is heated, and the outer peripheral surface of the metal shell is evenly pressed in the diameter-reducing direction so that the metal shell is A method of manufacturing an exhaust gas purifying apparatus, comprising: a heating compression step of compressing a target diameter smaller than an initial diameter; and a releasing step of releasing heating and pressurizing the metal shell.

According to the exhaust gas purifying apparatus (Claim 1) and the method for manufacturing the exhaust gas purifying apparatus (Claim 2 or later) of the present invention, a substantially columnar purifying unit having a mat wound around a cylindrical metal shell is inserted. After that, by uniformly pressing the outer peripheral surface of the metal shell in the diameter reducing direction in a state where the metal shell is heated, the metal shell is compressed to a target diameter smaller than its initial diameter, and the mat and the purification unit are made of cylindrical metal. Can be held in the shell. Particularly, in the present invention, by simultaneously heating the metal shell and uniformly pressing in the diameter reducing direction, the internal stress is increased due to the relationship between the pressing force for maintaining the diameter reduced state and the thermal expansion force of the metal. Stress relaxation occurs at the same time. As a result, some change occurs in the microscopic structure of the metal forming the shell, and the metal shell loses its impact resilience by plastically deforming in the reduced diameter state. Therefore, even if the pressure applied to the outer peripheral surface of the metal shell is released, springback hardly occurs, and the permanent diameter reduction of the metal shell is achieved almost in accordance with the target diameter.

As a result of the diameter of the metal shell being reduced to a target diameter smaller than its initial diameter, a surface pressure corresponding to the amount of the diameter reduction is generated, and the friction force based on the surface pressure causes the mat and the purification unit to have a cylindrical metal shape. Stable in the shell. That is, according to the present invention, in the step of reducing the diameter of the metal shell, there is no uncertain factor in the dimension setting such as springback,
The accuracy of setting the diameter of the metal shell, that is, the setting accuracy of the difference (gap) between the inner radius of the metal shell and the outer radius of the purification unit is dramatically improved as compared with the conventional art. Therefore, it becomes easy to optimize the surface pressure exerted on the purification unit and the metal shell by the mat, and avoid the risk of catalyst carrier damage or crushing of the mat while maintaining the necessary and sufficient surface pressure for stable holding of the catalyst carrier. Can be secured.

According to a third aspect of the present invention, in the method of manufacturing the exhaust gas purifying apparatus according to the second aspect, the end opening portion of the metal shell is subjected to spinning processing so that the end opening portion has a desired shape. It is characterized in that it further comprises a spinning step of imparting.

In the manufacturing method of the present invention, since the metal shell is of the insert type construction, the thickness of the end opening portion of the metal shell is substantially uniform from the beginning to the entire circumference. Therefore, the end opening portion can be subjected to spinning, and the desired shape can be freely given by the spinning.

According to a fourth aspect of the present invention, in the method for manufacturing an exhaust gas purifying apparatus according to the third aspect, the heating and uniform pressurizing operations in the heating and compressing step are performed on a metal shell as a work in the spinning process. The feature is that it also serves as chucking.

According to this method, the chucking of the work (metal shell), which is necessary during the spinning process, also serves as the heating and uniform pressing operations in the heating and compression step. Therefore, the heating and the uniform pressurization of the metal shell and the spinning process for the end opening portion of the metal shell can be simultaneously performed in parallel, and the working efficiency can be significantly improved.

According to a fifth aspect of the present invention, in the method for manufacturing an exhaust gas purifying apparatus according to any one of the second to fourth aspects,
The heating temperature in the heat compression step is 200 ° C. or higher and lower than the melting point of the constituent metal of the metal shell.

This limits the preferable range of the heating temperature in the heat compression step. The heating temperature at which springback after compression can be avoided may vary depending on the material conditions such as the material of the metal shell and the plate thickness, but when the metal shell is composed of a general-purpose iron-based material (for example, stainless steel) The lower limit of the heating temperature is preferably about 200 ° C. When the heating temperature is lower than 200 ° C., it is necessary to lengthen the time of heating and uniform pressurization to produce an effect of avoiding springback, which lowers productivity. Further, heating for a long time may damage the mat due to excessive heat transfer to the mat. Therefore, it is preferable to increase the heating temperature as much as possible to shorten the absolute time of heating and uniform pressurization.

On the other hand, the upper limit of the heating temperature is preferably lower than the melting point of the constituent metal of the metal shell. This allows
It is possible to prevent excessive softening and melting collapse of the metal shell. In the case of a metal shell composed of a general-purpose iron-based material, the optimum heating temperature range is 20
It is about 0 ° C to 400 ° C.

In the method for manufacturing an exhaust gas purifying apparatus according to any one of claims 2 to 5, the substantially columnar purifying unit is a ceramic catalyst carrier carrying an exhaust gas purifying catalyst or a wall flow monolith type ceramic diesel. It is preferably a particulate filter (claim 6). In the exhaust gas purifying apparatus using such a ceramic purifying unit, the present manufacturing method is extremely useful.

In the exhaust gas purifying apparatus according to claim 1, "The heating temperature of the metal shell is 200 ° C. or higher,
"The melting point of the constituent metal of the metal shell is lower than that", "The metal that forms the metal shell is an iron-based material", "The end opening of the metal shell has a cone shape by spinning. ”,“ The substantially columnar purification unit is a ceramic catalyst carrier carrying an exhaust gas purification catalyst ”, or“ the substantially columnar purification unit is a wall flow monolith-type ceramic diesel particulate filter ” Is preferred.

[0023]

BEST MODE FOR CARRYING OUT THE INVENTION An embodiment in which the present invention is embodied in a catalytic converter as an exhaust gas purifying apparatus will be described below with reference to the drawings.

FIG. 3 shows a completed state of the catalytic converter manufactured by the manufacturing procedure described later. As shown in FIG. 3, the catalytic converter includes a metal shell 1, a catalyst carrier 2 as a purification unit, and a mat 3.

The metal shell 1 is a kind of case for accommodating the catalyst carrier 2 and the mat 3, and is made of metal (more preferably, iron-based material such as cast iron or stainless steel). The body portion of the metal shell 1 is formed in a cylindrical shape, and the inside thereof provides a storage space for the catalyst carrier 2 and the mat 3. Both front and rear end portions (end opening portions) 1a, 1b of the body portion of the metal shell 1 are formed in a cone shape whose diameter is gradually narrowed for connection with an exhaust pipe (not shown). The catalyst carrier 2 is a substantially cylindrical ceramic carrier carrying an exhaust gas purification catalyst such as a NOx reduction catalyst, and a large number of exhaust gas passages 2a extending in the axial direction of the carrier are formed inside the carrier.

The mat 3 is a kind of filler which is interposed between the outer peripheral surface of the catalyst carrier 2 and the inner peripheral surface of the body of the metal shell 1. The mat 3 is formed, for example, of a mixture of alumina or silica-based inorganic fibers and an inorganic or organic binder in a mat shape (or a sheet shape). The mat 3 has various roles, and one of the most important roles exerts a surface pressure on the outer peripheral surface of the catalyst carrier 2 and the inner peripheral surface of the metal shell 1, and the catalyst carrier is generated by the frictional force based on the surface pressure. 2 is to be stably held in the metal shell 1.

The catalytic converter of this embodiment is manufactured by the following procedure. First, the outer diameter or circumference of the ceramic catalyst carrier 2 is measured in advance. Then, as shown in FIG. 1, a mat 3 is wrapped around the catalyst carrier 2, and the catalyst carrier 2 wound with the mat 3 is inserted into a cylindrical metal shell 1 having a body length longer than that of the catalyst carrier 2. .
At this time, the catalyst carrier 2 and the mat 3 are housed and arranged in the middle of the metal shell 1 in the axial direction.

Next, the body portion of the metal shell 1 accommodating the catalyst carrier 2 and the mat 3 is chucked by the chuck mechanism 10 as shown in FIGS. The chuck mechanism 10 is arranged in the vicinity of the spinning processing device SM,
Alternatively, it is a work gripping mechanism that constitutes a part of the spinning processing device SM, and has a plurality (eight in this example) of chuck claws 11. As shown in FIG. 4, eight chuck claws 11 are provided around a cylindrical work (that is, the metal shell 1) at equal angular intervals. Each chuck claw 11 is
It is provided so that it can approach and separate toward the center of the work,
All eight chuck claws 11 are synchronously driven by a drive mechanism (not shown). The heating means 1 is provided inside each chuck claw 11.
2 are provided (see FIG. 4). Examples of the heating means 12 arranged in the chuck claw 11 include a heating wire that generates heat by electricity and a heat medium (eg, high heat-resistant silicone oil) flowing in a passage in the chuck claw 11.

In chucking, first, the metal shell 1 is made up of the eight chuck claws 11 constituting the chuck mechanism 10.
The outer peripheral surface of the metal shell 1 is evenly pressed in eight directions to securely grip the metal shell 1. At that time, the heating means 12 in the chuck claws 11 is operated to raise the surface temperature of each chuck claw 11 to about 200 ° C. to 400 ° C. in advance. Chuck claw 11
After confirming that the gripping with the
By gradually increasing the pressing force by, the diameter of the metal shell 1 is forcibly reduced from the initial diameter (natural diameter in the unpressurized state) to a predetermined target diameter. The target diameter at the time of pressure compression is determined by referring to the outer diameter or the circumferential length of the catalyst carrier 2 which is measured first. The concept of setting the target diameter will be described later in detail.

While the body portion of the metal shell 1 is heated to a high temperature by the plurality of chuck claws 11 and is kept pressed in the diameter reducing direction, as shown in FIG. Spinning is performed on the rear end portion 1b by the spinning device SM. Then, the front and rear ends 1a and 1b are deformed into a cone shape (see FIG. 3). The heating and pressurization of the body portion of the metal shell 1 are maintained until the spinning process is completed. Front and rear ends 1
After the spinning process for a and 1b is completed, the pressing force of each chuck claw 11 is released and the metal shell 1 is removed from the chuck mechanism 10. Thus, the catalyst carrier 2 is stably held in the metal shell 1 based on the surface pressure exerted by the mat 3, and the catalytic converter as shown in FIG. 3 is completed.

The factors that determine the surface pressure exerted by the compressed mat 3 on each contact surface are the mat material, fiber diameter, and
Material properties such as length can be mentioned, but such material properties are limited in terms of heat resistance and other required performance, and the range of material selection is not so wide. Then,
The surface pressure of the mat 3 mainly depends on the catalyst carrier 2 and the metal shell 1.
Filling amount of mat per unit volume (filling density G
BD). There is a quadratic curve correlation between the surface pressure of the mat and the GBD, for example, as shown in FIG. 5, and the surface pressure tends to increase as the GBD increases.

The graph of FIG. 6 shows the characteristics of the mat 3 when the mat 3 is mounted in a catalytic converter having a final outer diameter of 140 mm, specifically, the inner radius of the metal shell 1 and the catalyst carrier 2.
3 shows the correlation between the difference between the outer radius and the outer radius (i.e., gap GAP) and GBD. As can be seen from this graph, the mat 3 mounted in the catalytic converter tends to have a higher GBD as the GAP becomes smaller. However, the mat 3 is, so to speak, a random aggregate of inorganic fibers, and inevitably causes quality variations. For this reason, the GAP / GBD characteristic of the mat 3 does not appear as a sharp single characteristic line, but is expressed as a downward sloping characteristic band having a certain width as shown in FIG.

After recognizing that the mat 3 has a band-like characteristic as shown in FIG. 6, the final pressure after the completion of the catalytic converter is ensured so that the surface pressure for obtaining a sufficient holding force of the catalyst carrier 2 can be secured. It is necessary to set the mat packing density (GBD) and thus the gap (GAP). At this time, the range of GBD must be selected in consideration of ensuring a sufficient surface pressure while preventing the compressive fracture (fiber collapse) of the inorganic fibers forming the mat 3. Specifically, the metal shell 1
The GBD that can generate the minimum surface pressure necessary for stably holding the catalyst carrier 2 therein is set as the lower limit value GB1 when the range is selected, and the maximum allowable value of the GBD that can avoid the fiber collapse is set as the range. The upper limit value is GB2. In the graph of FIG. 6, the lower limit value GB1 = 0.24 and the upper limit value GB2 = 0.40.

Then, the allowable range of the gap GAP is determined so that the entire characteristic band can be accommodated between the lower limit value GB1 and the upper limit value GB2 of the GBD allowable range. That is, it is not preferable that even a part of the characteristic band of the mat exceeds the upper limit value GB2. Therefore, the GAP value corresponding to the intersection of the horizontal line of GBD = 0.40 (= GB2) and the upper side of the characteristic band is set to the gap allowable range. Is the lower limit value GA2. Since it is not preferable that even a part of the characteristic band of the mat falls below the lower limit value GB1, the GAP value corresponding to the intersection of the horizontal line of GBD = 0.24 (= GB1) and the lower side of the characteristic band is the gap allowable range. Becomes the upper limit value GA1.

In this way, the allowable range (lower limit value GA2 to upper limit value GA1) of the gap GAP that can secure the sufficient surface pressure while preventing the fiber collapse of the mat 3 is determined. The gap GAP is the difference between the final inner radius of the metal shell 1 and the outer radius of the catalyst carrier 2, and since the outer radius of the catalyst carrier 2 is almost constant throughout the manufacturing process, G
Decreasing AP means that the degree of diameter reduction of the metal shell 1 is correspondingly large. That is, the metal shell 1
The target inner radius when reducing the diameter is the difference between the target inner radius and the actual outer radius of the catalyst carrier 2 calculated from the measured value of the outer diameter or circumference of the catalyst carrier 2 (gap target value GAt). It is determined to be within the allowable range of the gap.
Since it is desirable to secure a surface pressure as high as possible within the allowable range of the gap, the gap is normally set to the lower limit value GA.
The target inner radius of the diameter reduction processing is selected so as to be close to 2.

According to the manufacturing method of the present embodiment, since the press-compacting diameter machining of the metal shell 1 is performed under heating, the internal stress is caused by the relationship between the pressurizing force for maintaining the contracted state and the thermal expansion force of the metal. And the stress relaxation occur at the same time, and as a result, the metal shell loses its impact resilience by plastically deforming in the reduced diameter state.
Therefore, even if the pressure applied to the metal shell 1 is released,
Almost no return due to springback. Therefore, the value GAt close to the lower limit value GA2 of the allowable gap range shown in FIG.
Can be selected as, and the actual machining can realize a gap almost according to the target value. However, in the actual metal shell 1, there are slight variations in the plate thickness, and considering the tolerance as a safety margin in advance leads to the prevention of defective products. The value GAt is larger than the lower limit GA2 of the gap allowable range by the plate thickness tolerance k (GAt = GA2 + k).

On the other hand, according to the conventional manufacturing method in which the press-compacting diameter machining of the metal shell 1 is performed in the non-heated state (cold state), the radial return ΔR due to the springback when the pressurizing force is released.
Occurs inevitably. If this gap return ΔR is taken into consideration in advance and the gap target value GAt ′ in the compression diameter machining is set to GA2 + k−ΔR, the target value GA
Since t'is less than the lower limit GA2 of the allowable gap range, some or all of the mat 3 will be crushed during the diameter reduction process. In order to avoid this, even if the gap target value GAt ′ at the time of diameter reduction processing is at least GA2 + k (=
GAt), but in that case, a radial return ΔR 'occurs due to springback when the pressure is released,
The final gap becomes GA2 + k + ΔR ', which is larger than the final gap (GA2 + k) in the case of this embodiment. That is, in the conventional manufacturing method in which spring back is unavoidable, the lower limit G of the allowable gap range is set under the condition that fiber collapse is prevented in the diameter reduction processing stage.
The diameter of the metal shell 1 cannot be reduced to the nearest A2,
If the processing conditions other than the diameter reduction processing are the same, only a low surface pressure can be obtained as compared with the case of the present embodiment.

As described above, according to this embodiment,
Since the diameter does not return due to the spring back even when the pressure is released after the compression / diameter processing under heating, the surface pressure of the mat 3 is maximized without fiber crushing both during and after the processing. be able to. In other words,
In the manufacturing method of the present embodiment, the allowable range of the packing density control of the mat 3 is wider than that of the conventional method, and it is easy to improve the surface pressure, that is, the catalyst carrier holding force.

Further, according to this embodiment, the metal shell 1
Since the holding power of the catalyst carrier 2 in the inside is higher than in the conventional case, the catalytic converter can be installed in the vertical direction without fear of the catalyst carrier 2 falling off. Further, when it is clear that the holding force of the catalyst carrier 2 can be made to be a necessary and sufficient level by adopting the manufacturing method of this embodiment, a design in which the thickness of the mat 3 is made thinner than in the conventional case is adopted. The design options for reducing manufacturing costs are expanded.

In recent years, in order to reduce the size of the catalytic converter and improve the warm-up property, the partition walls forming the catalyst carrier have been made thinner, and as a result, the mechanical strength of the catalyst carrier tends to decrease. It is in. For this reason, FIG.
Then, the upper limit of the GBD allowable width was determined in consideration of the possibility of fiber crushing, but the upper limit of the GBD allowable width is determined by giving priority to avoiding the destruction of the catalyst carrier rather than the possibility of fiber crushing. It should be added that there may be cases.

(Modification) The embodiment of the present invention may be modified as follows. In the above-described embodiment, the heating and uniform pressing operation by the chuck mechanism 10 is performed also as chucking for the spinning process, but a heating and compression step of uniformly pressing the metal shell 1 in the diameter reducing direction while heating the metal shell 1 is performed. , The spinning process step may be temporally staggered, and each may be performed as a separate step.

The metal shell 1 is preheated by using, for example, a heating furnace, and the metal shell 1 is uniformly pressed by a chuck mechanism (the heating means 12 may not be provided) in a state where heat is not suppressed. You may do it. That is, in the present invention, it is sufficient that the metal shell 1 is in a predetermined heating state when the metal shell 1 is uniformly pressed.

The shape imparting to the end opening of the metal shell 1 may be performed by a processing method other than the spinning process. Also, regarding the shape given to the end opening,
It is not limited to the cone shape.

The present invention may be applied to an exhaust gas purifying apparatus having a wall flow monolith type ceramic diesel particulate filter (DPF) built therein.

[0045]

As described above in detail, according to the present invention, in the exhaust gas purifying apparatus adopting the insertion type metal shell structure, the purifying unit is stabilized while avoiding the risk of damage to the purifying unit and crushing of the mat. It is possible to secure a necessary and sufficient surface pressure for holding. Further, according to the manufacturing method of the present invention, such an exhaust gas purifying device can be reliably manufactured. That is, it becomes easy to avoid both the risk of damage to the purification unit and the crushing of the mat during the compression process and the securing of a sufficient and sufficient surface pressure for stable holding of the purification unit.

[Brief description of drawings]

FIG. 1 is a perspective view showing a part of a manufacturing process of an exhaust gas purification device.

FIG. 2 is a cross-sectional view showing chucking and spinning of a metal shell.

FIG. 3 is a cross-sectional view of the exhaust gas purification device after completion of spinning processing.

FIG. 4 is an A- of FIG. 2 showing an example of chucking of a metal shell.
A line sectional view.

FIG. 5 is a graph showing the relationship between the packing density (GBD) of the mat and the surface pressure.

FIG. 6 is a graph showing the relationship between the gap (GAP) and the packing density (GBD) of the mat, which illustrates the characteristics of the mat when mounted in the exhaust gas purification device.

FIG. 7 is an explanatory diagram showing an outline of springback in the related art.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Metal shell, 1a, 1b ... Front end and rear end (end opening portion) of the metal shell, 2 ... Catalyst carrier (purification unit), 3 ... Mat.

─────────────────────────────────────────────────── ─── Continuation of front page (51) Int.Cl. ⁷ Identification code FI theme code (reference) B01J 33/00 B21D 22/14 Z B21D 22/14 41/04 B 41/04 53/84 B 53/84 F01N 3/02 301B F01N 3/02 301 7/18 7/18 B01D 53/36 C F term (reference) 3G004 AA01 BA06 DA14 EA05 FA01 FA04 FA07 GA00 GA01 3G090 AA02 3G091 AA02 AB01 AB13 BA39 GA06 HA27 HA31 4D048 AA14 BA10X BB14 CA01 CA08 CC02 CC04 CC08 CD05 4G069 AA01 AA08 CA02 CA03 CA18 EA18 EA27 FA01 FB29 FB66 FB69 FB70 FC07

Claims (6)

[Claims] 1. A metal shell that defines a substantially cylindrical storage space, a substantially columnar purification unit installed in the storage space, and a metal shell and the purification unit. An exhaust gas purification device equipped with a mat, wherein after inserting a substantially columnar purification unit in which a mat is wound into a cylindrical metal shell, the metal shell is heated and the outer peripheral surface of the metal shell is evenly reduced in the radial direction. By applying pressure
An exhaust gas purifying device characterized in that the metal shell and the purification unit are held in a cylindrical metal shell by compressing the metal shell to a target diameter smaller than its initial diameter. 2. A metal shell that defines a substantially cylindrical storage space, a substantially columnar purification unit installed in the storage space, and a metal shell and the purification unit. A method of manufacturing an exhaust gas purifying device including a mat, comprising: an inserting step of inserting a substantially columnar purifying unit around which a mat is wound into a cylindrical metal shell; and heating a metal shell containing the mat and the purifying unit. In this state, the outer peripheral surface of the metal shell is uniformly pressed in the radial contraction direction to compress the metal shell to a target diameter smaller than its initial diameter, and a heating and compression process for releasing the heat and pressure applied to the metal shell. A method for manufacturing an exhaust gas purification device, comprising: 3. The exhaust according to claim 2, further comprising a spinning step of applying a spinning process to an end opening portion of the metal shell to give a desired shape to the end opening portion. Method for manufacturing gas purifier. 4. The exhaust gas purification according to claim 3, wherein the heating and uniform pressurizing operations in the heating compression step also serve as chucking of a metal shell as a work in the spinning process. Device manufacturing method. 5. The heating temperature in the heating and compression step is 200.
The method for manufacturing an exhaust gas purifying apparatus according to claim 2, wherein the melting point of the constituent metal of the metal shell is not less than 0 ° C. and not more than the melting point of the metal shell. 6. The purification unit having a substantially columnar shape is a ceramic catalyst carrier carrying an exhaust gas purification catalyst or a wall flow monolith type ceramic diesel particulate filter.
5. The method for manufacturing the exhaust gas purification device according to any one of items 1 to 5.