JP4652555B2 - Catalytic converter, holding sealing material for catalytic converter - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a catalytic converter and a holding seal material for a catalytic converter.
[0002]
[Prior art]
Conventionally, an internal combustion engine using gasoline or light oil as a fuel has been used for more than 100 years as a power source for vehicles, particularly automobiles. However, it has been a problem that exhaust gas is harmful to health and the environment. After that, various types of exhaust gas purifying catalytic converters have been proposed as devices for removing CO, NOx, PM, etc. contained in the exhaust gas. Has reached the point. A normal exhaust gas purifying catalytic converter includes a catalyst carrier, a metal shell covering the outer periphery of the catalyst carrier, and a holding sealing material disposed in a gap therebetween. As the catalyst carrier, a cordierite carrier formed in a honeycomb shape is used, and a catalyst such as platinum is supported on the carrier.
[0003]
A method for manufacturing the above catalytic converter will now be briefly described.
First, a holding seal material having a predetermined shape is produced by punching out a mat material made of ceramic fibers. Next, the holding sealing material is wound around the outer peripheral surface of the catalyst carrier. In that case, generally, the both winding ends of the holding sealing material are fixed at a plurality of locations using an organic tape made of vinyl or the like. Next, the metal shell is divided into two in advance, and a catalyst carrier around which a holding sealing material is wound is disposed and sandwiched. As a result of such a canning operation, a catalytic converter is completed. In addition to the canning method as described above, a method (press-in method) in which a catalyst carrier around which a holding sealing material is wound is press-fitted into a pipe-shaped metal shell has been conventionally practiced.
[0004]
[Problems to be solved by the invention]
By the way, the exhaust gas passed to the catalytic converter is likely to generate a pulse pressure in addition to a high temperature of several hundred degrees Celsius or higher. Therefore, the gas inflow end of the holding sealing material that is particularly susceptible to the exhaust gas is gradually eroded and the holding sealing material is deteriorated. As a result, there has been a problem that the support retainability is lowered within a relatively short period of time, and the catalyst support is easily rattled or damaged, or gas leakage from the seal portion is likely to occur. That is, conventionally, sufficient durability has not been imparted to the holding sealing material.
[0005]
In addition, as a method for preventing the occurrence of wind erosion and improving the durability of the holding sealing material, for example, a holding sealing material obtained by impregnating the whole mat material made of ceramic fibers with an inorganic binder and sintering the same is used. This has been proposed in the past.
[0006]
However, the above-described conventional techniques for impregnation and sintering not only increase the production cost of the holding sealing material, but also have a problem that the assembling operation becomes difficult because the flexibility of the holding sealing material is impaired.
[0007]
This invention is made | formed in view of said subject, The 1st objective is to provide the catalytic converter excellent in durability.
The second object of the present invention is to provide a holding seal material for a catalytic converter that is suitable for manufacturing the above-mentioned excellent catalytic converter because it is less expensive and is less susceptible to wind erosion despite having no loss in flexibility. It is in.
[0008]
[Means for Solving the Problems]
In order to solve the above problems, in the invention according to claim 1, a catalyst carrier, a cylindrical metal shell covering the outer periphery of the catalyst carrier, and a holding sealing material disposed in the gap between them In the catalytic converter, the holding sealing material Is a mat-like material comprising ceramic fiber, In the holding sealing material at least At the gas inflow end By providing a thicker part than the other part made of the same material as the holding sealing material, and arranging the holding sealing material in the gap between the catalyst carrier and the metal shell, the thick part is compressed. It becomes a part with higher packing density than other parts The gist of the catalytic converter is as follows.
[0010]
Claim 2 The invention described in claim 1 In the holding sealing material, both the mating ends are provided with a convex mating portion and a concave mating portion which can be engaged with each other, and the gas inflow side region and the convex mating portion of the both mating ends are provided. The high filling density portion is also provided on the gas inflow side edge.
[0011]
Claim 3 The invention described in claim 1 Or 2 In the holding sealing material, the filling density of the low filling density portion is 0.20 g / cm. ³ ~ 0.35g / cm ³ The filling density of the high filling density portion in the holding sealing material is 0.35 g / cm. ³ ~ 0.50g / cm ³ It was said that.
[0012]
Claim 4 The invention described in claim 1 to claim 1 3 In any one of these, the width | variety of the high packing density site | part in the said holding sealing material shall be 1/20 times-1/5 times the length along the axial direction of the said catalyst carrier.
[0013]
Claim 5 The invention described in claim 1 to claim 1 3 In any one of these, the width | variety of the high filling density site | part in the said holding sealing material shall be 5-30 mm.
Claim 6 In the invention described in the above, the holding sealing material disposed in the gap between the catalyst carrier and the cylindrical metal shell covering the outer periphery of the catalyst carrier, It is formed in a mat-like material containing ceramic fibers, and is made of the same material as the holding sealing material at least on the gas inflow side end. Provide thicker parts than other parts By arranging the gap between the catalyst carrier and the metal shell, the thick part is compressed and becomes a part having a relatively higher packing density than other parts. The gist of the holding seal material for catalytic converters is as follows.
[0015]
Claim 7 The invention described in claim 6 The thick portion is formed by attaching a sub-holding sealing material having a narrower width on the main holding sealing material.
[0016]
Claim 8 The invention described in claim 6 The thick portion was formed by folding the edge of the holding sealing material.
The “action” of the present invention will be described below.
[0017]
According to the first aspect of the present invention, by providing a portion having a relatively high packing density at a gas inflow side end portion where wind erosion is likely to occur, the progress of wind erosion in the portion can be delayed. Therefore, it is possible to provide a catalytic converter that maintains the support holding ability and the sealability of the gap portion over a long period of time and has excellent durability.
[0019]
Claim 2 According to the invention described in (2), the progress of wind erosion can be delayed also for the gas inflow side region at both ends of the winding and the gas inflow side edge of the convex fitting portion. Therefore, it can be made more durable.
[0020]
Claim 3 According to the invention described in, since the filling density of the low filling density part and the filling density of the high filling density part are set in the preferred ranges, sufficient improvement in durability can be achieved while maintaining suitable assembly. can do.
[0021]
The packing density of the low packing density region is 0.20 g / cm ^Three If it is less than the range, even if a high packing density portion is provided, there is a possibility that sufficient carrier holding property and gap portion sealing property cannot be obtained as a whole. The packing density of the low packing density region is 0.35 g / cm ^Three And the packing density of the high packing density region is 0.35 g / cm ^Three In the case of less than this, it becomes difficult to have a difference in density between the two parts. Moreover, the packing density of the high packing density part is 0.50 g / cm. ^Three If it exceeds 1, the assembly may become difficult, and even if it can be assembled, the catalyst carrier may be destroyed.
[0022]
Claim 4 Since the ratio between the width and the length is set within a suitable range, the durability can be sufficiently improved while maintaining a suitable assembly property.
[0023]
If the width is less than 1/20 times the length, the length required to delay the progress of wind erosion is not ensured, and the durability may not be sufficiently improved. Conversely, when the width exceeds 1/5 times the length, assembly may be difficult.
[0024]
Claim 5 According to the invention described in (1), by setting the width of the high filling density portion within a suitable range, it is possible to achieve a sufficient improvement in durability while maintaining a suitable assembly property.
[0025]
If the width is less than 5 mm, the length necessary for delaying the progress of wind erosion cannot be secured, and the durability may not be sufficiently improved. Conversely, if the width exceeds 30 mm, assembly may be difficult.
[0026]
Claim 6 According to the invention described in Particularly on the gas inflow end where wind erosion is likely to occur Since the part thicker than the other part is provided in the part, after the assembly, the part is compressed in the thickness direction in the gap to become a high filling density part. Accordingly, the presence of the high filling density portion makes it difficult for wind erosion to occur, and as a result, a holding seal material with excellent durability can be obtained. Further, the holding sealing material of the present invention has an advantage that the manufacturing cost can be reduced unlike the conventional holding sealing material in which the entire mat material is impregnated with an inorganic binder and sintered. In addition, since the holding sealing material has flexibility, there is an advantage that it is excellent in assembling property.
[0028]
Claim 7 According to the invention described in (2), it is possible to relatively easily form a thick part that will later become a high filling density part, and to make the thick part into an arbitrary shape.
[0029]
Claim 8 According to the invention described in (2), a thick portion can be formed using only one type of holding sealing material without attaching a separate sub-holding sealing material on the main holding sealing material.
[0030]
DETAILED DESCRIPTION OF THE INVENTION
[First Embodiment]
Hereinafter, a catalytic converter for an automobile exhaust gas purifying apparatus according to an embodiment of the present invention will be described in detail with reference to FIGS.
[0031]
The catalytic converter 1 of the present embodiment shown in FIG. 2 is provided in the middle of an exhaust pipe of an engine in a vehicle body of an automobile. Since the distance from the engine to the catalytic converter 1 is relatively short, the exhaust gas having a high temperature of about 700 ° C. to 900 ° C. is supplied to the catalytic converter 1. When the engine is a lean burn engine, the catalytic converter 1 is supplied with exhaust gas having a higher temperature of about 900 ° C. to 1000 ° C.
[0032]
As shown in FIG. 2, the catalytic converter 1 of this embodiment is basically arranged in the gap between the catalyst carrier 2, the metal shell 3 that covers the outer periphery of the catalyst carrier 2, and both 2 and 3. The holding sealing material 4 is configured. In the figure, the left end side is a gas inflow side end E1, and the right end side is a gas outflow side end E2.
[0033]
The catalyst carrier 2 is manufactured using a ceramic material typified by cordierite or the like. The catalyst carrier 2 is a columnar member having a circular cross section. The catalyst carrier 2 is preferably a honeycomb structure having a large number of cells 5 extending along the axial direction. A noble metal catalyst such as platinum or rhodium capable of purifying exhaust gas components is supported on the cell wall. In addition to the cordierite carrier, for example, a honeycomb porous sintered body such as silicon carbide or silicon nitride may be used as the catalyst carrier 2.
[0034]
As the metal shell 3, for example, when a press-fitting method is adopted at the time of assembly, a metal cylindrical member having an O-shaped cross section (pipe shape) is used. In addition, as a metal material for forming the cylindrical member, a metal excellent in heat resistance and impact resistance (for example, a steel material such as stainless steel) is preferably selected. When a so-called canning method is employed instead of the press-fitting method, a metal cylindrical member having an O-shaped cross section divided into a plurality of pieces along the axial direction (that is, a clam shell) is used.
[0035]
In addition, in the case of adopting a tightening method at the time of assembling, for example, a metal cylindrical member having a C-shaped or U-shaped cross section, in other words, a metal having a slit (opening) extending along the axial direction only at one place. A cylindrical member is used. In this case, when the catalyst carrier 2 is assembled, the catalyst carrier 2 fixed with the holding sealing material 4 is placed in the metal shell 3 and the metal shell 3 is wound in this state, and the opening end is joined ( Welding, bonding, bolting, etc.). Joining operations such as welding, bonding, and bolting are similarly performed when the canning method is adopted.
[0036]
The holding sealing material 4 of this embodiment is formed using a mat-like material of heat resistant inorganic fibers as a main material. Suitable heat-resistant inorganic fibers include, for example, alumina-silica ceramic fibers. In addition, for example, crystalline alumina fiber, silica fiber, rock wool, glass fiber, carbon fiber, or the like may be used.
[0037]
As shown in FIG. 1B, the holding sealing material 4 of the present embodiment is a long mat-like material. A convex matching portion 7 is formed on one winding end 4a of the holding sealing material 4, and a concave matching portion 8 is formed on the other winding end 4b. As shown in FIGS. 1 (a) and 2, the holding sealing material 4 is wound around the outer peripheral surface 2 a of the catalyst carrier 2, and both the winding ends 4 a and 4 b are fixed using the organic tape 9 in this state. Is done. At the time of winding, the convex matching part 7 and the concave matching part 8 are engaged with each other.
[0038]
As shown in FIG. 1 (b), a portion 11 thicker than the other portions is provided at one end edge of one side surface of the holding sealing material 4 of the present embodiment. The thick portion 11 is a portion that is compressed after the holding sealing material 4 is assembled and becomes the high filling density portion P1.
[0039]
Specifically, the thick portion 11 is formed by attaching a sub-holding sealing material 13 on the main holding sealing material 12. The sub-holding sealing material 13 is formed to be somewhat narrower than the main holding sealing material 12.
[0040]
The width W1 of the high packing density portion P1 in the holding sealing material 4 is preferably 1/20 to 1/5 times the length L1 along the axial direction of the catalyst carrier 2 and further 1/15 times. It is better to be 1/7 times. If the width W1 is less than 1/20 times the length L1, the length necessary for delaying the progress of wind erosion cannot be secured, and the durability may not be sufficiently improved. Conversely, if the width W1 exceeds 1/5 times the length L1, assembly may be difficult.
[0041]
The width W1 of the high filling density portion P1 in the holding sealing material 4 is preferably 5 mm to 30 mm, and more preferably 10 mm to 20 mm. If the width W1 is less than 5 mm, the length required to delay the progress of wind erosion is not ensured, and the durability may not be sufficiently improved. Conversely, when the width W1 exceeds 30 mm, assembly may be difficult.
[0042]
The thickness of the thick part 11 in the holding sealing material 4 before assembly is preferably 1.1 to 3.0 times the thickness of the non-thick part, and further 1.5 to 2. It is better to be 5 times. When the thickness is less than 1.1 times, it is difficult to cause a difference in density between the high filling density part P1 and the low filling density part P2 after assembly. Conversely, if the thickness exceeds 4.0 times, assembly may be difficult.
[0043]
In addition, the thickness of the holding sealing material 4 itself before assembly (thickness of a portion that is not thick) is about 1.1 to 4.0 times the gap formed by the catalyst carrier 2 and the metal shell 3, and Is preferably set to about 1.5 to 3.0 times. If the thickness is less than 1.1 times, suitable carrier holding property and gap sealability may not be obtained as a whole. On the other hand, if the thickness exceeds 4.0 times, it may not be possible to improve the assembly.
[0044]
In the state where the holding sealing material 4 is assembled, the filling density of the low filling density portion P2 is 0.20 g / cm. ^Three ~ 0.35g / cm ^Three The filling density of the high filling density region P1 is 0.35 g / cm. ^Three ~ 0.50g / cm ^Three It is good to become.
[0045]
The filling density of the low filling density part P2 is 0.20 g / cm. ^Three If it is less than this, even if the high filling density portion P1 is provided, there is a possibility that sufficient carrier holding property and gap portion sealing property cannot be obtained as a whole. The filling density of the low filling density part P2 is 0.35 g / cm. ^Three Or the filling density of the high filling density region P1 is 0.35 g / cm ^Three In the case of less than this, it becomes difficult to have a difference in density between the two parts. Further, the filling density of the high filling density portion P1 is 0.50 g / cm. ^Three If it exceeds, assembly may be difficult. Even if it can be assembled, the catalyst carrier 2 may be destroyed.
[0046]
Next, a procedure for manufacturing the catalytic converter 1 will be described.
First, a mat-like material having a predetermined thickness as a material of the holding sealing material 4 is produced by a conventionally known method. Next, the mat-like material is punched into a predetermined shape using a molding die, whereby the main holding sealing material 12 and the sub-holding sealing material 13 having a narrower width than that are obtained from one mat-like material. Of course, the main holding sealing material 12 and the sub holding sealing material 13 may be obtained separately from mat-like materials having different thicknesses and materials.
[0047]
Then, the holding sealing material 4 having the thick portion 11 is produced by attaching the auxiliary holding sealing material 13 on the main holding sealing material 12. In addition, as a method of attaching the auxiliary holding sealing material 13 on the main holding sealing material 12, there are, for example, adhesion and sewing.
[0048]
Next, the holding sealing material 4 is wound around the outer peripheral surface 2 a of the catalyst carrier 2, and both the winding ends 4 a and 4 b are fixed with the organic tape 9. Of course, the holding sealing material 4 may be fixed by using means other than the organic tape 9.
[0049]
Thereafter, the desired catalytic converter 1 is completed by press-fitting, canning or tightening.
Examples will be described in detail below.
(Example)
As the catalyst carrier 2, a cordierite monolith having an outer diameter of 130 mmφ and a length of 100 mm was used. As the metal shell 3, a cylindrical member made of SUS304 having a wall thickness of 1.5 mm, an inner diameter of 140 mmφ, and an O-shaped cross section was used. As the holding sealing material 4, a long mat-like material (thickness 8 mm) made of an alumina-silica ceramic fiber was used as a forming material. The main holding sealing material 12 and the sub-holding sealing material 13 were obtained from this mat-like material, and both were bonded using an adhesive, whereby the holding sealing material 4 having a thick portion 11 was produced.
[0050]
The width of the main holding sealing material 12 was set to 100 mm, and the width of the auxiliary holding sealing material 13 was set to 10 mm. Therefore, the width W1 of the thick portion 11 that later becomes the high filling density portion P1 is 10 mm, and the thickness is 16 mm.
[0051]
Then, the holding sealing material 4 was wound and fixed with the organic tape 9, and such a catalyst carrier 2 was press-fitted into the metal shell 3 to obtain the catalytic converter 1. In this example, the catalytic converter 1 could be assembled relatively easily without any particular difficulty. In the assembled state, the filling density of the low filling density region P2 is 0.20 g / cm. ^Three The packing density of the high packing density region P1 is 0.40 g / cm. ^Three It was.
[0052]
Next, a test was conducted in which the catalytic converter 1 assembled as described above was actually mounted on a 3-liter gasoline engine and continuously operated. Thereafter, when the sample was disassembled and observed, no damage to the catalyst carrier 2 or wind erosion of the holding sealing material 4 was observed, and no traces of exhaust gas leakage were observed. Further, no abnormal noise was generated during traveling, and the catalyst carrier 2 was securely held without rattling. That is, this catalytic converter 1 was excellent in performance in addition to being easily assembled.
[0053]
Therefore, according to the present embodiment, the following effects can be obtained.
(1) In the case of the catalytic converter 1 of the present embodiment, gas flows into a portion (that is, a high filling density portion P1) having a relatively higher packing density than other portions (that is, a low filling density portion P2) in the holding sealing material 4. It is provided at the side end E1. Therefore, it is possible to delay the progress of wind erosion at the gas inflow side end E1 where wind erosion is likely to occur. Therefore, the catalyst holding property of the catalyst carrier 2 and the sealing property of the gap portion are maintained for a long time. Therefore, rattling / breakage of the catalyst carrier 2 and exhaust gas leakage hardly occur, and the catalytic converter 1 having excellent durability can be obtained.
[0054]
(2) In this embodiment, the filling density of the low filling density part P2, the filling density of the high filling density part P1, the ratio between the width W1 and the length L1 of the holding sealing material 4, and the width of the high filling density part P1 are as described above. Is set in a preferable range. For this reason, sufficient improvement in durability can be achieved while maintaining a suitable assembly property.
[0055]
(3) Since the holding sealing material 4 of the present embodiment is provided with the thicker portion 11 than the other portions at one end edge thereof, the entire mat material is impregnated with an inorganic binder and sintered. Unlike the conventional holding sealing material, the production cost is low. Moreover, since the holding sealing material 4 of the present embodiment has flexibility, it is not difficult to wind it along the shape of the outer peripheral surface 2a of the catalyst carrier 2, and in this sense, it is excellent in assemblability. .
[Second Embodiment]
Next, a second embodiment of the present invention will be described with reference to FIG. Here, the points different from the first embodiment will be mainly described, and the common points are only given the same member numbers, and the description thereof will be omitted.
[0056]
In the case of this holding sealing material 4 shown in FIG. 3, the gas inflow side region 21 at the winding end 4a, the gas inflow side region 22 at the winding end 4b, and the gas inflow side edge 23 of the convex joining portion 7 A sub-holding sealing material 13 is attached. Therefore, after the assembly, the gas inflow side regions 21 and 22 and the gas inflow side edge 23 are also compressed in the thickness direction to become the high filling density portion P1.
[0057]
Therefore, according to the present embodiment, the progress of wind erosion can also be delayed at the above-described locations, and therefore the durability can be further improved. In the present embodiment, the holding sealing material 4 is produced by bonding the sub holding sealing material 13 on the main holding sealing material 12. For this reason, even if the thick portion 11 to be the high filling density portion P1 later is bent as shown in FIG. 3, it can be formed relatively easily.
[Third Embodiment]
Next, a third embodiment of the present invention will be described with reference to FIGS. Here, the points different from the first embodiment will be mainly described, and the common points are only given the same member numbers, and the description thereof will be omitted.
[0058]
In the case of the holding sealing material 4 in FIG. 4, the two thicker holding seal materials 13 are attached on one main holding sealing material 12, so that the thick portions 11 are provided at both end edges.
[0059]
Therefore, after assembling, due to the compression of the thick portions 11 at the two locations, in addition to the gas inflow end E1 which is particularly susceptible to wind erosion, a high filling density region P1 is also generated at the gas outflow end E2. (See FIG. 5). Therefore, the progress of wind erosion in both the parts can be surely delayed, and the catalytic converter 1 having higher durability can be obtained.
[Fourth Embodiment]
Next, a fourth embodiment of the present invention will be described with reference to FIGS. Here, the points different from the first embodiment will be mainly described, and the common points are only given the same member numbers, and the description thereof will be omitted.
[0060]
Here, the holding sealing material 4 is produced by a method different from that of the first embodiment or the like. That is, in the holding sealing material 1 of the present embodiment, the thick part 11 having a thickness twice as large as that of other parts is formed by folding the edge of the holding sealing material 4 twice. . Therefore, even if a separate material corresponding to the auxiliary holding sealing material 13 is not prepared, the thick portion 11 can be formed basically using only one type of holding sealing material 4. .
[0061]
In addition, you may change embodiment of this invention as follows.
When the catalytic converter 1 is configured using the holding sealing material 4 as in the first embodiment, the holding sealing material 4 may be wound with the sub holding sealing material 13 facing the outer peripheral surface 2a.
[0062]
-It is not limited to the holding sealing material 4 of a shape like 1st-4th embodiment, For example, it is good also as a holding sealing material of a simple shape without the matching parts 7 and 8. FIG.
-So long as the flexibility of the holding sealing material 4 is not impaired, it is allowed to impregnate the holding sealing material 4 with an organic binder as an auxiliary material.
[0063]
The cross-sectional shape of the catalyst carrier 2 is not limited to a perfect circle as shown in FIG. 1 or the like, and may be, for example, an ellipse or an ellipse. In this case, the cross-sectional shape of the metal shell 3 is preferably changed to an elliptical shape, an oval shape, or the like accordingly.
[0064]
-After the catalyst carrier 2 is accommodated in the metal shell 3, the method of fastening the metal shell 3 and fixing both ends thereof is not limited to welding, and other methods are adopted. It is also possible to do.
[0065]
In the embodiment, the present invention is embodied in the catalytic converter 1 for an automobile exhaust gas purification device, but is not limited thereto, and is embodied as, for example, a diesel particulate filter (DPF), a catalytic converter for a fuel cell reformer, or the like. Of course, it is acceptable.
[0066]
Next, in addition to the technical ideas described in the claims, the technical ideas grasped by the embodiment described above are listed below.
(1) Claim 7 The thick portion is formed by adhering the sub-holding sealing material on the main holding sealing material. Therefore, according to this technical idea, since a thick part can be formed easily, a holding sealing material can be obtained relatively easily and at low cost.
[0067]
(2) Claim 7 The thick portion is formed by adhering the sub holding sealing material having the same thickness on the main holding sealing material. Therefore, according to this technical idea, since only one type of mat-like material as a forming material is required, the holding sealing material can be obtained easily and inexpensively.
[0068]
【The invention's effect】
As detailed above, claims 1 to 5 According to the invention described in (1), a catalytic converter having excellent durability can be provided.
[0069]
Claim 2 According to the described invention, a catalytic converter with higher durability can be provided.
Claim 3 , 4 , 5 According to the invention described in (1), it is possible to achieve a sufficient improvement in durability while maintaining a suitable assembly property.
[0070]
Claim 6 ~ 8 According to the invention described in the above, since the wind erosion hardly occurs even though it is inexpensive and the flexibility is not impaired, it is possible to provide a holding seal material for a catalytic converter suitable for manufacturing the above excellent catalytic converter. it can.
[Brief description of the drawings]
FIG. 1A is a perspective view showing a state in which a holding sealing material according to a first embodiment embodying the present invention is wound around a catalyst carrier, and FIG. 1B is a perspective view of the holding sealing material before winding.
FIG. 2 is a cross-sectional view of the catalytic converter of the first embodiment.
3A is a perspective view showing a state where the holding sealing material of the second embodiment is wound around a catalyst carrier, and FIG. 3B is a perspective view of the holding sealing material before winding.
4A is a perspective view showing a state where the holding sealing material of the third embodiment is wound around a catalyst carrier, and FIG. 4B is a perspective view of the holding sealing material before winding.
FIG. 5 is a sectional view of a catalytic converter according to a third embodiment.
6A is a perspective view showing a state where the holding sealing material of the fourth embodiment is wound around a catalyst carrier, and FIG. 6B is a perspective view of the holding sealing material before winding.
FIG. 7 is a cross-sectional view of a catalytic converter according to a fourth embodiment.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 ... Catalytic converter, 2 ... Catalyst support body, 3 ... Metal shell, 4 ... Holding sealing material, 4a, 4b ... Winding end, 7 ... Convex part, 8 ... Concave part, 11 ... Thick part , 12 ... main holding sealing material, 13 ... sub-holding sealing material, 21, 22 ... gas inflow side region at the winding end, 23 ... gas inflow side edge of convex fitting portion, P1 ... part with high filling density (high filling) Density part), P2 ... low packing density part, W1 ... width of the high packing density part, L1 ... length along the axial direction of the catalyst carrier, E1 ... gas inflow side end, E2 ... gas outflow side end.

Claims (8)

In a catalytic converter comprising a catalyst carrier, a cylindrical metal shell covering the outer periphery of the catalyst carrier, and a holding seal material disposed in a gap between them, the holding seal material includes a ceramic fiber. The holding sealing material is provided with a thicker part at least at the gas inflow side end of the holding sealing material than other parts made of the same material as the holding sealing material, and the holding sealing material is provided between the catalyst carrier and the metal shell. By disposing in the gap, the thick part is compressed to become a part having a relatively higher packing density than other parts . Provided at both winding ends of the holding sealing material are a projecting mating portion and a concave mating portion that can be engaged with each other, and a gas inflow side region at the both mating ends and a gas inflow side of the projecting mating portion. The catalytic converter according to claim 1, wherein the high packing density portion is also provided at an edge. The filling density of the low filling density portion in the holding sealing material is 0.20 g / cm ^{3 to} 0.35 g / cm ³ , and the filling density of the high filling density portion in the holding sealing material is 0.35 g / cm ^{3 to} 0. catalytic converter according to claim 1 or 2, characterized in that a .50g / cm ^3. Width of the high packing density portion in the holding sealing material, any one of claims 1 to 3, wherein the a 1/20 to 1/5-fold the length along the axial direction of the catalyst carrier The catalytic converter according to item 1. Width of the high packing density portion in the holding sealing material, the catalytic converter according to any one of claims 1 to 3, characterized in that it is 5 mm to 30 mm. A holding sealing material disposed in a gap between a catalyst carrier and a cylindrical metal shell covering an outer periphery of the catalyst carrier, and is formed in a mat-like material including ceramic fibers, and at least a gas By providing a thicker part at the inflow side end than the other part made of the same material as the holding sealing material and disposing it in the gap between the catalyst carrier and the metal shell, the thick part is compressed. A holding sealer for a catalytic converter, characterized in that the part has a relatively higher packing density than the part . 7. The holding seal material for a catalytic converter according to claim 6, wherein the thick portion is formed by attaching a sub-holding seal material having a narrower width on the main holding seal material. . The said thick site | part is formed by folding up the edge of a holding sealing material, The holding sealing material for catalytic converters of Claim 6 characterized by the above-mentioned.

Images