JP2009150242A - Buffer member for ceramic honeycomb, and its manufacturing method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a structure capable of suppressing manufacturing cost and offering excellent cushioning performance, while ensuring the ease of fitting into a catalytic converter or DPF. <P>SOLUTION: Between a casing 1 and a honeycomb catalytic carrier 3, a buffer member 5a is disposed, which is formed into an elastically compressible annular shape by collecting elastic-metal filaments in finely bent states. In the buffer member 5a, an annular reinforcement ring 10 is embedded, which has higher rigidity than a buffer material body 6a built of the filaments and is made of a heat resistant material. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention is directed to a ceramic honeycomb catalyst carrier incorporated in a catalytic converter installed in an exhaust passage through which exhaust gas is passed in order to treat harmful substances contained in exhaust gas discharged from an automobile engine, and DPF (Diesel Particulate). The present invention relates to an improvement of a ceramic honeycomb cushioning member and a method of manufacturing the same, which hold a honeycomb incorporated in a filter) in a casing.

Exhaust gas discharged from an automobile engine contains harmful substances such as nitrogen oxides (NO _x ), carbon monoxide (CO), and hydrocarbons (HC). If these harmful substances are released into the atmosphere as they are, they will cause various pollutions such as photochemical smog. Therefore, the exhaust gas is widely detoxified by the catalytic converter provided in the exhaust path. . Such a catalytic converter incorporates a catalyst attached to the surface of a catalyst carrier in which a ceramic is formed in a honeycomb shape. Such a catalyst support made of ceramic is very brittle because it is made of a thin ceramic material, which originally has poor toughness, and is easily damaged by vibration and impact. For this reason, it is necessary to support the catalyst carrier in a buffering manner inside the casing constituting the catalytic converter. Such a structure for supporting the catalyst carrier in a shock-absorbing manner inside the casing is well known, for example, as described in many documents such as Patent Documents 1 to 3.

  8 to 9 schematically show an example of the structure of a catalytic converter that has been generally practiced in the past. The casing 1 is formed into a substantially cylindrical shape by plastically deforming a metal plate, and has an exhaust inlet 2 and an exhaust outlet (not shown) at both ends in the axial direction. Of these, the exhaust gas fed into the casing 1 from the exhaust inlet 2 is passed through the micro flow path provided in the honeycomb catalyst carrier 3 held in the middle part of the casing 1 and adhered to the inner surface of the micro flow path. After detoxification treatment based on contact with the catalyst, it is sent out from the exhaust outlet. A shielding ring 4 called an interlam mat is provided between the outer peripheral surface of the honeycomb catalyst carrier 3 and the inner surface of the casing 1, and the outer peripheral surface of the honeycomb catalyst carrier 3 and the inner peripheral surface of the casing 1 are provided. This prevents the exhaust from bypassing (passing without being detoxified by the catalyst). In addition, there is a structure in which a metal mesh cushioning material is installed between the shielding ring 4 and the buffer member 5 described below, or a cushioning material is provided instead of the shielding ring 4 (without providing the shielding ring 4).

  Furthermore, the outer peripheral edge portions of the both end surfaces in the axial direction of the honeycomb catalyst carrier 3 are supported in a buffering manner by the buffer member 5 which is the subject of the present invention. In the case of the conventional structure, both the buffer members 5 are configured as shown in FIG. 11 by connecting the buffer material body 6 and the reinforcing ring 7 as shown in FIG. Of these, the cushioning material body 6 is formed in an annular or string-like shape that is elastically compressible by gathering together a metal filament having elasticity and heat resistance, such as stainless spring steel, in a finely bent state. Yes. For example, a metal mesh formed into a cylindrical shape by knit knitting is cut into a predetermined length and then compressed in the axial direction to form an annular shape (including not only a circular shape but also an oval shape and an elliptical shape) in many cases. . Alternatively, there is a case in which a wire mesh braided with the filament is compressed into a string shape and then cut to a predetermined length and then bent (or bent and then cut to a predetermined length). . In the former case, since it is formed in an annular shape in advance, it is easy to combine the buffer member 5 with the reinforcing ring 7. On the other hand, in the latter case, since a plurality of types of buffer members 5 having different diameters can be made from the same type of material, the procurement cost of the parts can be reduced. Therefore, which structure is adopted is determined by design considerations.

  On the other hand, the reinforcing ring 7 is formed by bending a heat-resistant metal plate such as a stainless steel plate, and has a substantially J-shaped or substantially U-shaped cross section. The reinforcing ring 7 and the buffer body 6 are combined with each other in a state in which the buffer body 6 is fitted in the reinforcing ring 7 to form the buffer member 5. In a state where the catalytic converter is assembled, a portion of the buffer material body 6 that protrudes in the axial direction from the reinforcing ring 7 is abutted against the outer peripheral edge portions of the axial end faces of the honeycomb catalyst carrier 3, Regardless of the axial vibration or impact applied between the honeycomb catalyst carrier 3 and the casing 1, damage such as chipping is prevented from occurring at the outer peripheral edges of the axial end faces of the honeycomb catalyst carrier 3. In addition, although illustration is abbreviate | omitted, as a reinforcement ring which comprises a buffer member, a cross-sectional shape has a L-shape, and there exist a mere annular shape whose cross-sectional shape is a straight line.

  The conventional buffer member 5 as described above not only increases the manufacturing cost, but also impairs the degree of freedom in designing the catalytic converter. That is, the reinforcing ring 7 is manufactured by using an expensive stainless steel plate as a raw material in order to ensure heat resistance, and subjecting this stainless steel plate to press working such as punching and bending. Since the entire reinforcing ring 7 is annular, it is inevitable that the yield of the material is poor, and that the cost of the material is increased due to the high price of the material itself. Further, before the buffer member 5 is incorporated in the catalytic converter, the buffer material body 6 and the reinforcing ring 7 are prevented from being separated from each other by spot welding or the like. It is necessary to combine them in a non-separable manner by means such as press fitting, and the manufacturing cost increases from this aspect as well.

  The conventional buffer member 5 includes a reinforcing ring 7, and the installation space for the buffer member 5 is increased by the volume of the reinforcing ring 7. The reinforcing ring 7 is considered to be a rigid body that hardly undergoes elastic deformation with respect to the displacement direction of the honeycomb catalyst carrier 3, and a buffering action cannot be expected. When the buffer member 5 having such a reinforcing ring 7 is used to effectively hold and hold the honeycomb catalyst carrier 3, the buffer member main body 6 has a sufficient volume. Is increased by the presence of the reinforcing ring 7, and the degree of freedom in designing the catalytic converter is impaired. In other words, when the installation space provided to the buffer member 5 is limited, the buffer action obtained by the buffer member 5 is reduced based on the presence of the reinforcing ring 7, and the honeycomb catalyst carrier is reduced. The buffering action of 3 is impaired.

  If the reinforcing ring 7 is omitted, the reduction of the manufacturing cost and the improvement of the buffer performance can be achieved at the same time, but the rigidity of the entire buffer member becomes extremely low, and the work of assembling the buffer member at a predetermined position of the catalytic converter is performed. It becomes difficult to do. If the reinforcing ring 7 is omitted, the shape retaining property of the buffer member is impaired. Then, when vibration or the like accompanying traveling acts on the buffer member in a state where the rigidity of the buffer member is further decreased as the temperature rises, a part of the buffer member is displaced toward the inner diameter side of the honeycomb catalyst carrier 3. Thus, the honeycomb catalyst carrier 3 is easily disengaged from a predetermined position between the end surface of the honeycomb catalyst carrier 3 and the inner surface of the casing 1. For this reason, it is not possible to employ a structure in which the reinforcing ring 7 is simply omitted and only the cushioning body 6 is used.

JP 7-279655 A JP-A-9-195759 JP 2001-300228 A

  In view of the circumstances as described above, the present invention can reduce the manufacturing cost while ensuring the ease of assembly to the catalytic converter (or DPF) and the shape retention after the assembly, and has excellent buffer performance. The present invention was invented to realize the obtained ceramic cushioning member for honeycomb and the manufacturing method thereof.

Of the buffer member for a ceramic honeycomb and the manufacturing method thereof according to the present invention, the invention for the buffer member for a ceramic honeycomb according to claim 1 is made of a metal having elasticity and heat resistance as in the conventional buffer member described above. The filaments (thread-like materials) are assembled in a state of being bent finely (infinitely with a radius of curvature much smaller than the radius of curvature of the reinforcing ring after completion) to form an elastically compressible ring. However, unlike the conventional buffer member, a reinforcing ring made of a heat-resistant metal plate is not provided.
In particular, in the ceramic honeycomb cushioning member of the present invention, an annular reinforcing ring made of a heat-resistant material having a larger rigidity than the cushioning material body made of the filament is embedded therein.

  As for the heat resistance of the metal constituting the filament and the reinforcing ring, the required functions (corrosion resistance and rigidity) can be ensured regardless of the high temperature generated when using the catalytic converter or DPF. And Specifically, it is preferable to secure 900 ° C. or higher when constituting a buffer member for a catalytic converter, and 600 ° C. or higher when constituting a buffer member for DPF. For example, austenitic stainless steel such as SUS304 or nickel alloy steel can be preferably used. Also, martensitic stainless steel can be used if the above temperature condition is satisfied.

In addition, among the methods for manufacturing a ceramic honeycomb cushioning member according to the present invention, the manufacturing method according to claim 2 is such that a metal filament having elasticity and heat resistance is first knitted to form a cylindrical wire mesh. Form. Next, the wire mesh is cut into a predetermined length and then compressed in the axial direction, and the filaments are gathered in a finely bent state to form an elastically compressible ring.
In particular, in the method for manufacturing a ceramic honeycomb cushioning member according to claim 2, the wire net is rounded while being folded back in the radial direction from one end, and the inside of the wire net is accompanied by the rounding operation. It encloses an annular reinforcing ring made of a heat-resistant material that has greater rigidity than the cushioning material body made of filaments. The reinforcing ring is an annular intermediate material embedded inside. After that, the intermediate material is compression-molded to a state in which a gap sufficient to allow elastic deformation of each filament is interposed between adjacent filaments to obtain a completed shape and size.

According to a third aspect of the present invention, a ceramic honeycomb cushioning member is manufactured by first knitting metal filaments having elasticity and heat resistance to form a band-shaped wire mesh. Next, the wire mesh is compressed in any one direction with respect to the surface direction (the surface expansion direction and the direction perpendicular to the thickness direction) to form a string-like intermediate material, and then the intermediate material having a predetermined length is bent. Thus, it is an elastically compressible ring. It does not matter before and after the work of cutting to a predetermined length and the work of compressing the wire mesh to make an intermediate material.
In particular, in the method for manufacturing a buffer member for a honeycomb of a ceramic according to claim 3, the shock absorber made of the filaments is formed inside the wire mesh by rolling the wire mesh from one end portion. A core material made of a heat-resistant material, having a rigidity higher than that of the main body, is wrapped, and this core material is used as a rod-shaped first intermediate material embedded therein. Next, the first intermediate material is compression-molded to a state in which a gap sufficient to allow elastic deformation of each filament is interposed between adjacent filaments to obtain a string-like second intermediate material. Thereafter, the second intermediate material is curved in an annular shape to obtain a completed shape and dimensions. In this state, the core material is also bent at the same time to form an annular reinforcing ring.

According to the ceramic honeycomb cushioning member of the present invention configured as described above, the manufacturing cost can be suppressed while securing the ease of assembly to the catalytic converter or the DPF and the shape retention after the assembly, and it is excellent. Buffer performance.
In other words, the ceramic honeycomb cushioning member of the present invention can secure the necessary rigidity of the entire cushioning member by the reinforcing ring embedded inside, so that it is easy to assemble this buffering member at a predetermined position of the catalytic converter or DPF. Can be done.
In addition, even after assembly, the shape is not easily distorted by vibration or the like, and it is possible to reliably prevent falling off from a predetermined position.

Further, the reinforcing ring can be made by cutting a heat-resistant metal wire (wire) such as stainless steel into a predetermined length. The procurement cost of the wire material can be kept lower than the procurement cost of the plate material, and in the process of constructing the reinforcing ring from this wire material, there is almost no waste material (scrap that is discarded without being a reinforcing ring). For this reason, the manufacturing cost of the ceramic honeycomb buffer member can be suppressed.
Furthermore, the volume of the reinforcing ring with respect to the entire volume of the ceramic honeycomb cushioning member can be reduced (compared to the above-described conventional structure including the reinforcing ring made of a metal plate). For this reason, among the ceramic honeycomb cushioning members that can be installed in a predetermined space, the ratio of the cushioning material body part that can be elastically deformed by crushing the filament can be increased, and an excellent cushioning effect can be obtained. It is done.

  1 to 7 show an example of an embodiment of the present invention corresponding to claims 1 and 2. The buffer member 5a for the ceramic honeycomb of this example is similar to the above-described conventional buffer member 5 (see FIGS. 8, 9, and 11), as shown in FIGS. The honeycomb catalyst carrier 3 is supported between the outer peripheral edge portion and the step portion 9 formed on the inner surface of the casing 1 so as to buffer the inside of the casing 1. The buffer member 5a, like the conventional buffer member 5, is elastically compressible by gathering elastic metal filaments in a finely bent state, and has an annular shape as shown in FIG. However, unlike the conventional buffer member 5, the reinforcing ring 7 (see FIGS. 8 to 11) made of a heat-resistant metal plate is not provided. Therefore, in the case of the buffer member 5a of this example, an annular buffer material body 6a that is elastically compressible is exposed on the entire surface of the buffer member 5a.

  In the case of the buffer member 5a of this example instead of omitting the reinforcing ring 7, as shown in FIGS. 4 to 5, the buffer material body 6a made of the filament is formed inside the buffer material body 6a. An annular reinforcing ring 10 made of a heat-resistant material having greater rigidity is embedded. As the reinforcing ring 10, for example, a wire (wire) made of a heat-resistant metal such as stainless steel and having an outer diameter (cross-sectional diameter, wire diameter) of about 0.2 to 1.5 mm can be used. The outer diameter of the wire rod is as small as possible as long as the rigidity required in the state of the reinforcing ring 10 can be ensured. From the viewpoint of saving material costs, the outer diameter of the buffer body 5a in the buffer member 5a is also reduced. It is also preferable from the aspect of increasing the ratio and ensuring the buffer performance. Therefore, the outer diameter of the wire is appropriately set according to the size of the honeycomb to be supported, which varies depending on the size of the engine to be mounted (for passenger cars or for large vehicles such as trucks). .

According to the buffer member 5a for the ceramic honeycomb of this example having the above-described configuration, the manufacturing cost can be suppressed while ensuring the ease of assembly to the catalytic converter or the DPF and the shape retention after the assembly. In addition, excellent buffer performance can be obtained.
That is, the buffer member 5a can ensure the rigidity required for the buffer member 5a as a whole by the reinforcing ring 10 embedded therein. In other words, even when the buffer member 5a is installed between the outer peripheral edge portion of the both end surfaces in the axial direction of the honeycomb catalyst carrier 3 and the step portion 9 formed on the inner surface of the casing 1, the buffer member 5a is predetermined. The shape can be maintained. Therefore, it is possible to easily install the buffer member 5 a between the outer peripheral edge portions of the both end surfaces in the axial direction of the honeycomb catalyst carrier 3 and the step portions 9 formed on the inner surface of the casing 1.
Further, even after the assembly, since the buffer member 5a is held in a predetermined shape by the reinforcing ring 10, even if the rigidity of the buffer member 5a is somewhat lowered due to the temperature rise, the buffer member The shape of 5a is not easily distorted by vibration or the like. For this reason, it is possible to reliably prevent the buffer member 5a from dropping from a predetermined position, that is, between the outer peripheral edge portions of the both end surfaces in the axial direction of the honeycomb catalyst carrier 3 and the stepped portion 9.

  Further, the reinforcing ring 10 can be made by cutting a metal wire (wire) having heat resistance such as stainless steel into a predetermined length. The procurement cost of the wire material is kept lower than the procurement cost of the plate material, and in the process of making the reinforcing ring 10 from this wire material, there is almost no waste material (scrap that is discarded without becoming a reinforcement ring). In other words, when an annular member is obtained by punching a plate material, the inner diameter side portion becomes waste material as it is, and the outer diameter side portion also has considerable waste material portion. The entire wire thus cut becomes the reinforcing ring 10. Furthermore, the operation of manufacturing the reinforcing ring 10 can be easily performed only by bending the wire cut to a predetermined length and welding the butted portions at both ends as necessary. For this reason, the manufacturing cost of the buffer member 5a can be suppressed by reducing the procurement cost of the material, improving the yield, and facilitating the processing operation.

  Furthermore, the volume of the reinforcing ring 10 relative to the entire volume of the buffer member 5a can be reduced (compared to the conventional structure having the reinforcing ring 7 made of a metal plate shown in FIGS. 8 to 11). For this reason, a filament is crushed among the said buffer member 5a installable in the predetermined space between the axial peripheral edge outer peripheral part of the said honeycomb catalyst support | carrier 3, and the step part 9 formed in the inner surface of the said casing 1 As a result, the ratio of the cushioning material main body 6a that can be elastically deformed can be increased, and an excellent cushioning action can be obtained.

Although the manufacturing method of the above buffer member 5a is not specifically limited, For example, it can manufacture by the following methods. In the first method, metal filaments having elasticity and heat resistance such as stainless steel filaments are knitted to form a cylindrical wire mesh 11 as shown in FIG. When the cylindrical wire mesh 11 is rolled into a roll shape as shown in FIG. 6B, a reinforcing ring 10 as shown in FIG. 6A is wrapped inside. That is, after the wire mesh 11 is cut to a predetermined length, the reinforcing ring 10 is disposed around one end of the wire mesh 11 as shown in FIG. Next, the wire mesh 11 is rolled from one end side to the outer diameter side to form an annular intermediate material in which the reinforcing ring 10 is embedded. In this way, when the wire mesh 11 is rounded, the gap in the axial direction is made larger than the gap in the radial direction so that the cross-sectional shape is elliptical or oval. After that, the intermediate material is compression-molded to a state in which a gap sufficient to allow elastic deformation of each filament is interposed between adjacent filaments to obtain a completed shape and size.
The timing of wrapping the reinforcing ring 10 in the wire mesh 11 is appropriately changed according to the position (position in the buffer member 5a) where the reinforcing ring 10 is to be installed. Further, the direction in which the cylindrical wire mesh 11 is rounded is not limited to the outer diameter side, but may be the inner diameter side. In the case of the inner diameter side, the reinforcing ring 10 is disposed on the inner diameter side of the wire mesh 11.

  Or although illustration is abbreviate | omitted, after forming a string-like intermediate material, this intermediate material can also be curved and it can also be set as the ring which can be compressed elastically. In this case, first, a metal filament having elasticity and heat resistance is knitted to form a belt-like wire mesh. Next, after cutting the wire mesh to a predetermined length, a linear core made of a heat-resistant material is disposed, for example, on one side of one end of the wire mesh. Then, from this state, the wire mesh is rolled from one end side to form a rod-shaped first intermediate material in which the core material is embedded. Next, the first intermediate material is compression-molded to a state in which a gap sufficient to allow elastic deformation of each filament is interposed between adjacent filaments to obtain a string-like second intermediate material. Thereafter, the second intermediate material is curved in an annular shape to obtain a completed shape and dimensions. In this state, the core material is also bent at the same time to form an annular reinforcing ring. The operation of cutting the wire mesh and the core material into a predetermined length may be performed at the stage of the first intermediate material after embedding the core material with the wire mesh, and further after compression molding, It may be done at the material stage. The timing at which the core material is arranged on one side of the wire mesh is also appropriately changed according to the position where the reinforcing ring is to be installed.

  The present invention is not limited to a buffer member for holding a ceramic honeycomb catalyst carrier, but for holding a ceramic honeycomb constituting a DPF that collects graphite fine particles discharged from a diesel engine in a casing. The buffer member is also a target.

1 is a schematic partial cross-sectional view of a catalytic converter showing an example of an embodiment of the present invention. The A section enlarged view of FIG. The perspective view which takes out and shows a buffer member. The partial cutting perspective view of this buffer member. The expanded BB sectional drawing of FIG. The perspective view and sectional drawing which showed the reinforcement ring and buffer material main body which comprise a buffer member separately, respectively. FIG. 5 is a schematic cross-sectional view showing an example of a manufacturing method of the buffer member. FIG. 6 is a schematic partial cross-sectional view of a catalytic converter showing an example of a conventional structure. The C section enlarged view of FIG. Sectional drawing which shows the reinforcing ring and buffer material main body which comprise a buffer member in the state before coupling | bonding. Sectional drawing and the figure seen from the axial direction side of the buffer member comprised combining the reinforcement ring and the buffer material main body.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Casing 2 Exhaust inlet 3 Honeycomb catalyst support | carrier 4 Shielding ring 5, 5a Buffer member 6, 6a Buffer material main body 7 Reinforcement ring 8 Substrate part 9 Step part 10 Reinforcement ring 11 Metal mesh

Claims (3)

  By gathering elastic metal filaments in a finely bent state, an elastically compressible ring-shaped ceramic honeycomb cushioning member has greater rigidity than the cushioning material body made of the filaments. A ceramic cushioning member made of a heat-resistant material and having an annular reinforcing ring embedded therein.   By knitting a metal filament having elasticity and heat resistance into a cylindrical shape and cutting it into a predetermined length and then compressing it in the axial direction, the filaments are assembled in a finely bent state, In the manufacturing method of the shock absorbing member for a ceramic honeycomb having an annular shape that is elastically compressible, the wire net is rolled while being folded back in the radial direction from one end, and the inside of the wire mesh is accompanied with the rounding operation. An annular reinforcing ring made of a heat-resistant material, which has greater rigidity than the buffer material body made of filaments, is wrapped in an annular intermediate material embedded inside, and then the intermediate material is adjacent Compression molding is carried out to a state where a gap sufficient to allow the elastic deformation of each filament is allowed between the filaments. Method for producing a ceramic honeycomb for cushioning material, characterized in that that.   A belt-shaped wire mesh made of metal filaments with elasticity and heat resistance is compressed in the surface direction to form a string-like intermediate material, and then this intermediate material having a predetermined length is bent and elastically compressed. In a method for manufacturing a buffer member for a ceramic honeycomb having an annular shape, the wire mesh is rounded from one end, and the inside of the wire mesh is larger than the buffer material body made of the filaments as the rounding operation is performed. A rod-shaped first intermediate material that wraps a rigid, heat-resistant core material and embeds this core material inside, and then the first intermediate material is placed between adjacent filaments. After compression molding to a state where a gap sufficient to allow elastic deformation is provided to form a string-like second intermediate material, this second intermediate material is curved in an annular shape, Method for producing a ceramic honeycomb for cushioning material, characterized in that modulo.

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