WO2011034015A1

WO2011034015A1 - Retention structure of honeycomb structure in exhaust gas purification device

Info

Publication number: WO2011034015A1
Application number: PCT/JP2010/065695
Authority: WO
Inventors: 由章畠山; 土佐　真一
Original assignee: 本田技研工業株式会社
Priority date: 2009-09-15
Filing date: 2010-09-13
Publication date: 2011-03-24

Abstract

Provided is a retention structure of a honeycomb structure in an exhaust gas purification device, wherein the exhaust efficiency is not reduced while a honeycomb structure is mainly retained by a side surface retention member wound around the outer peripheral surface of the honeycomb structure, the honeycomb structure can be prevented from cracking, and the retention structure can be easily produced. The retention structure of a honeycomb structure is provided with a catalyst carrier (2) composed of a honeycomb structure, a metal case (3) within which the catalyst carrier (2) is retained, and a side surface retention member (4) provided between the catalyst carrier (2) and the metal case (3). The catalyst carrier (2) has a plurality of cells (21) and a coat layer (5) which covers the outer peripheral surface of the catalyst carrier (2). A projected portion (51) is formed on at least a part of the coat layer (5) in the circumferential direction, and the catalyst carrier (2) is positioned and secured to the metal case (3) via the side surface retention member (4) disposed on the outside of the projected portion (51).

Description

Holding structure of honeycomb structure in exhaust gas purification device

The present invention relates to a honeycomb structure holding structure in an exhaust gas purification apparatus.

2. Description of the Related Art There is known an exhaust gas purifying apparatus in which a catalyst carrier in which a catalyst such as platinum or rhodium is supported on a heat-resistant honeycomb structure is housed in a metal cylindrical case and used as a filter for purifying fluid. For example, in an automobile exhaust system, a so-called catalytic converter (catalyzer) is installed on the exhaust system path to purify nitrogen oxides (NOx), hydrocarbons (HC) and carbon monoxide (CO) contained in the exhaust gas. Is going.
In addition, as another exhaust gas purification device, a DPF (Diesel particulate filter) is known which collects particulate matter (PM) such as soot contained in exhaust gas by allowing the exhaust gas to permeate through a honeycomb structure as a filter. ing. Some DPFs have a continuous regeneration function by further supporting a catalyst such as platinum or rhodium on the honeycomb structure.
The honeycomb structure is made of, for example, ceramics, and a support member and a buffer member are provided between the honeycomb structure and the case in order to prevent breakage.

In the conventional exhaust gas purifying apparatus, a side surface holding member (support member) for restricting the radial movement of the honeycomb structure is provided between the outer peripheral surface of the cylindrical honeycomb structure and the inner peripheral surface of the case. An end holding member (buffer member) that restricts the movement of the honeycomb structure in the axial direction is attached between the peripheral edges of the upstream and downstream ends of the honeycomb structure and the holding frame provided on the inner peripheral surface of the case. ing.

In the exhaust gas purification device, the case expands in the axial direction of the honeycomb structure due to heat during operation of the internal combustion engine, so that a clearance is generated between the case and the honeycomb structure, and the honeycomb structure is axially moved by vibration of the internal combustion engine. When it vibrates, the end face of the honeycomb structure or the end face of the end portion holding member will be stepped and worn.

Therefore, for example, in Patent Document 1, in order to suppress step wear, an annular groove is formed along the circumferential direction on the outer periphery of the catalyst carrier (honeycomb structure), and the catalyst container containing the catalyst carrier is provided with this An annular recess projecting into the annular groove is formed, and a buffer member is disposed between the side surface of the annular groove and the side surface of the annular recess, thereby restricting the movement of the catalyst carrier in the axial direction (manifold) Converter).

Japanese Utility Model Publication No. 5-38318 (Fig. 3)

However, in the structure described in Patent Document 1, since the annular groove is formed along the circumferential direction on the outer periphery of the honeycomb structure, the cross-sectional area of the honeycomb structure is reduced by the annular groove, so that the flow path of the exhaust gas is reduced. There is a problem that the exhaust efficiency is lowered due to the throttle being reduced.
Further, since the honeycomb structure is a ceramic member composed of a plurality of cells such as a honeycomb shape or a monolith shape, there is a high possibility that a crack or the like is generated when the annular groove is formed.
Further, when installing the buffer member in the annular groove, the buffer member has to be once widened, which makes it difficult to manufacture and damages the buffer member and the honeycomb structure.

The present invention has been made in view of these points. The main structure is the holding by the side surface holding member wound around the outer peripheral surface of the honeycomb structure, and the exhaust efficiency is not reduced. It is an object of the present invention to provide a honeycomb structure holding structure in an exhaust gas purification apparatus that can suppress cracking and the like and can be easily manufactured.

The present invention is a honeycomb structure holding structure in an exhaust gas purification apparatus disposed in an exhaust passage, and has a plurality of cells and an outer peripheral surface covered with a coating layer, and the honeycomb structure. A metal case held inside, and a side surface holding member interposed between the honeycomb structure and the metal case, the honeycomb structure having a plurality of cells and an outer peripheral surface of the honeycomb structure The side surface holding member disposed on the outside of the convex portion, wherein the coat layer has a convex portion formed at least partially along a circumferential direction. It is characterized by being fixed to the metal case via

According to this configuration, the coat layer covering the outer peripheral surface of the honeycomb structure has the convex portions formed along the circumferential direction, and the honeycomb structure is made of metal via the side surface holding member disposed outside the convex portions. Since the position is fixed to the case, the cross-sectional area of the honeycomb structure does not decrease as in the case of forming the annular groove, and the reduction in exhaust efficiency can be suppressed. In addition, since the convex portions are formed in the coat layer, the member strength is not lowered as in the case of forming the annular groove, and cracking of the honeycomb structure can be prevented.
In addition, since a sufficient strength can be obtained by the coat layer having the convex portion, the thickness of the side surface holding member is reduced to increase the surface pressure, and the honeycomb structure is held in the axial direction and the radial direction by the side surface holding member. be able to. Therefore, conventionally, it is possible to omit the end holding member that has been installed on the peripheral edge of the upstream and downstream ends of the honeycomb structure, and it is possible to reduce the thickness of the side holding member. Mounting of the holding member is facilitated.

Further, the convex portion is configured by making the coat layer thicker than other portions, and the coat layer is mainly composed of ceramics, alumina, mullite, lithium aluminum silicate, silicon carbide, silicon nitride, It is preferably made of a material containing at least one selected from the group consisting of alumina titanate and cordierite.

According to such a configuration, since the convex portion is formed by thickly coating the coat layer, it can be handled in the coating layer manufacturing process, and the convex portion can be easily formed without complicating the manufacturing work. Can be formed.

Further, it is preferable that the metal case is reduced in diameter by a diameter reduction process in accordance with the surface shape of the convex portion, and the side surface holding member is fixedly held at a predetermined pressure.

According to such a configuration, since the diameter is reduced by, for example, a diameter reduction process such as spinning, the metal case is configured so that the honeycomb structure can be held in the metal case with a predetermined surface pressure while suppressing the displacement of the side surface holding member. Can be easily processed.

Further, the axial length dimension of the convex portion of the honeycomb structure is 0.3 to 1.0 times the axial length dimension of the honeycomb structure itself, and the outer diameter of the convex portion. Is preferably 1.01 to 1.2 times the outer diameter of the portion of the honeycomb structure not including the convex portion.

According to such a configuration, the contact area is sufficient to hold the honeycomb structure sufficiently while reducing the area of the side surface holding member, and the cell structure of the honeycomb structure is affected while holding the honeycomb structure on the side surface. Sufficient strength can be obtained.

Further, in the present invention, the side surface holding member is formed on an outer peripheral surface of the convex portion of the honeycomb structure including the concave portion by further forming a concave portion by recessing a part of the convex portion formed by the coat layer. In addition, it is preferable that the diameter of the metal case is reduced in accordance with the surface shape of the convex portion including the recess.

According to this configuration, by forming a recess in the convex portion, the metal case formed so as to enter the recess also thermally expands in the axial direction even when the metal case thermally expands in the radial direction. Thus, since the convex portion is pressed, the honeycomb structure can be reliably held by the metal case.

In the present invention, a plurality of protrusions are further formed on the surface of the protrusions formed of the coating layer at intervals in the axial direction, and the protrusions of the honeycomb structure including the plurality of protrusions are formed. It is preferable that the side surface holding member is attached to the outer peripheral surface of the portion, and the diameter of the metal case is reduced in accordance with the surface shape of the convex portion including the protruding portion.

According to this configuration, by forming a plurality of protrusions on the surface of the protrusion, even when the metal case is thermally expanded in the radial direction, the metal case fitted between the protrusions is also heated in the axial direction. By expanding, the metal case strongly meshes with the side surface holding member disposed on the outer peripheral surface of the protruding portion, so that vibration applied to the honeycomb structure can be suppressed and stably held.

Further, the present invention provides an end holding member that restricts the movement of the honeycomb structure in the axial direction at a position facing the upstream end and the downstream end of the convex portion formed of the coat layer. Preferably, the metal case is reduced in diameter by spinning so as to apply a predetermined pressure in the axial direction to the upstream end and the downstream end of the end holding member.

According to such a configuration, since the end holding member is mounted in addition to the side holding member, and these are directly fixed by the metal case, the side and end of the honeycomb structure can be held only by spinning. This makes it possible to improve workability.

In the present invention, it is preferable that a plurality of grooves are formed on the outer peripheral surface of the convex portion.

According to such a configuration, since a plurality of grooves are formed on the outer peripheral surface of the convex portion, the contact area between the side surface holding member and the convex portion increases, and the frictional force increases. Therefore, the retention strength of the honeycomb structure by the side surface holding member can be improved.

According to the present invention, the holding by the side surface holding member wound around the outer peripheral surface of the honeycomb structure is set as the main holding, and the cracking of the honeycomb structure can be suppressed without lowering the exhaust efficiency, and the manufacturing work can be suppressed. An easy carrier support structure for a catalytic converter can be provided.

It is sectional drawing of the catalytic converter which concerns on 1st Embodiment. It is a perspective view of a catalyst carrier. It is explanatory drawing of the formation method of a convex part. It is explanatory drawing of the assembly method of a catalytic converter. It is principal part sectional drawing of the catalytic converter which concerns on 2nd Embodiment. It is principal part sectional drawing of the catalytic converter which concerns on 3rd Embodiment.

The first embodiment of the present invention will be described in detail with reference to the drawings. In the description, the same elements are denoted by the same reference numerals, and redundant description is omitted. In addition, when describing a direction in this embodiment, it demonstrates based on the radial direction r and the axial direction a which are shown by the arrow in FIG. 1, FIG.

As shown in FIG. 1, a catalytic converter 1 to which the honeycomb structure holding structure according to the first embodiment is applied is a purification device that is installed on, for example, an exhaust path of an automobile and purifies harmful substances contained in exhaust gas. is there. The catalytic converter 1 includes a catalyst carrier 2 that supports a catalyst, a metal case 3 that houses the catalyst carrier 2, and a side surface holding member 4 that is installed between the catalyst carrier 2 and the metal case 3. .

As shown in FIGS. 1 and 2, the catalyst carrier 2 is formed by coating alumina on the surface of a ceramic honeycomb structure formed in a cylindrical shape, for example. The alumina coating layer contains a three-way catalyst such as platinum, palladium, or rhodium.
The catalyst carrier 2 has a plurality of cells 21 through which exhaust gas flows. The cell 21 is a hollow passage and is formed, for example, in a quadrangular shape in a cross-sectional view. The surface of the cell 21 is coated with the above-described three-way catalyst. The cell 21 is sealed at either the inflow side or the outflow side end, and the cells 21 with the inflow side sealed and the cells 21 with the outflow side sealed are alternately arranged.
The catalyst carrier 2 is made of ceramics, although nitrogen oxides (NOx), hydrocarbons (HC), and carbon monoxide (CO) in the exhaust gas come into contact with the three-way catalyst to cause a redox reaction and become high temperature. Therefore, the heat resistance is high, and since the honeycomb structure is used, the contact area with the exhaust gas is wide and the purification ability is high.
The catalyst carrier 2 is installed on the exhaust path with the axial direction of the honeycomb structure oriented in the flow direction of the exhaust gas.
The cross-sectional shape of the catalyst carrier 2 is not limited to a circular shape, and may be formed in an elliptical shape or a polygonal shape.

A coat layer 5 is formed on the outer peripheral surface of the catalyst carrier 2. The coat layer 5 is composed mainly of ceramics, and is selected from the group consisting of alumina, mullite, lithium aluminum silicate, silicon carbide (SiC), silicon nitride, alumina titanate (AT), cordierite, and the like. It is comprised with the material containing 1 type or 2 types. The thickness dimension of the

flat portions

5a and 5b described later of the coat layer 5 is preferably about 5 mm.

As shown in FIG. 2, the coat layer 5 is formed in an annular shape along the circumferential direction of the catalyst carrier 2 at the

flat portions

5 a and 5 b on the upstream side and the downstream side that are formed flat and in the center portion in the axial direction. And a convex portion 51. The convex part 51 is formed by making the thickness of the coat layer 5 larger than the

flat parts

5a and 5b. A method for forming the convex portion 51 will be described in detail later.

The convex portion 51 is formed in a mountain shape in which the central portion in the axial direction is the highest apex 52. On the upstream side and the downstream side of the top portion 52,

taper portions

53 and 53 that are reduced in diameter as they are separated from the top portion 52 are formed.
It is preferable that a plurality of

grooves

53a, 53a... Are formed on the surfaces of the tapered

portions

53, 53, for example, along the circumferential direction.

The length L1 of the convex portion 51 in the axial direction of the catalyst carrier 2 is 0.3 to 1.0 times (30% or more and 100% or less) of the length L2 of the catalyst carrier 2 in the axial direction. preferable. If it is smaller than 0.3 times, a sufficient holding area cannot be obtained, and if it is larger than 1.0 times, the weight of the catalyst carrier 2 becomes too large, and side surface holding becomes difficult.
The maximum outer diameter D1 of the convex portion 51 is preferably 1.01 to 1.2 times (101% to 120%) of the outer diameter D2 of the portion not including the convex portion 51 of the catalyst carrier 2. . This is because the mass of the honeycomb structure becomes too large and is difficult to hold, and the exhaust gas purification device becomes too large, making it difficult to mount and layout the engine.

The metal case 3 is a metal member that houses the catalyst carrier 2 and is formed in a substantially cylindrical shape. An upstream end portion 3a of the metal case 3 is connected to, for example, an exhaust manifold EX of an internal combustion engine branched into four. Moreover, the downstream end 3b of the metal case 3 is narrowed to a small diameter, and is connected to, for example, a silencer (not shown).

As shown in FIG. 1, the metal case 3 is processed into a shape along the surface shape of the coat layer 5 by, for example, spinning. For example, in the metal case 3, the holding portion 3 c that is a portion corresponding to the convex portion 51 of the coat layer 5 swells in the annular shape along the circumferential direction and radially outwardly in a mountain shape in a cross-sectional view. Yes. In the metal case 3, the upstream portion 3 d on the upstream side of the catalyst carrier 2 is narrowed to substantially the same diameter as the catalyst carrier 2. Thereby, it is possible to suppress the exhaust gas from the exhaust manifold EX from directly entering the gap between the catalyst carrier 2 and the metal case 3.

As shown in FIG. 1, the side surface holding member 4 is a member that prevents the catalyst carrier 2 from moving in the axial direction and the radial direction with respect to the metal case 3, and is formed on the convex portion 51 on the outer peripheral surface of the catalyst carrier 2. Installed in the corresponding range. The side surface holding member 4 also has a function of making it difficult for the heat of the catalyst carrier 2 to be transferred to the metal case 3.
The side surface holding member 4 is a wire mesh ring formed by forming metal fibers such as stainless steel into a cylindrical shape, and has elasticity (stretchability).
The inner diameter of the side surface holding member 4 is formed to be substantially the same as the outer diameter of the convex portion 51 of the catalyst carrier 2. Further, the thickness dimension of the side surface holding member 4 is preferably about 3 mm to 25 mm.

The material of the side surface holding member 4 is not limited to the metal fiber, and for example, one or more kinds of glass fiber, alumina fiber, carbon fiber, polyamide fiber, etc. are appropriately selected and used. Also good.
In the present embodiment, the side surface holding member 4 is formed in a cylindrical shape, but the present invention is not limited to this, and the side surface holding member 4 may be formed in a belt shape and wound around the convex portion 51. Further, by using a stretchable material, the side surface holding member 4 is formed in a cylindrical shape so that the inner diameter is smaller than the outer diameter of the convex portion 51 of the catalyst carrier 2, and the side surface holding member 4 is expanded to expand the catalyst carrier. 2, and the side surface holding member 4 may be fitted to the convex portion 51 exactly.

Next, a method for forming the convex portion 51 will be described with reference to FIG. FIG. 3 is an explanatory diagram of a method for forming a convex portion.
As shown in FIG. 3A, the material M of the coat layer 5 is sprayed from the spray S while rotating the catalyst carrier 2, so that the coat layer 5 is uniformly formed on the outer peripheral surface of the catalyst carrier 2.
Thereafter, the pair of shielding plates W, W are installed in accordance with the width forming the convex portion 51, and the material M of the convex portion 51 that is the same as the coat layer 5 is sprayed between the pair of shielding plates W, W. Thereby, the convex part 51 will be formed in the center part of the axial direction of the coat layer 5. FIG. In addition, the position of the top part 52 of the convex part 51 and the gradient of the taper part 53 can be changed by changing the interval between the shielding plates W and W and the position of the spray S.

Further, as shown in FIG. 3 (b), after the coat layer 5 is formed with a uniform thickness on the outer peripheral surface of the catalyst carrier 2, the convex portions 51 formed separately from the same material are bonded and fixed with an adhesive B. May be. In addition, what is necessary is just to adhere | attach the convex part 51, after dividing what was formed in the cylindrical shape by the separate part into 2 in an axial direction.
Further, as shown in FIG. 3C, after the coat layer 5 is formed on the outer peripheral surface of the catalyst carrier 2 with a uniform thickness so as to be equal to the thickness of the convex portion 51, an extra coat layer is formed with the bit T. 5 'may be cut and the convex part 51 may be formed. Further, instead of forming the coat layer 5 thick, an unnecessary material may be adhered and cut.

In addition, the formation method of the convex part 51 is not restricted to these, For example, although illustration is abbreviate | omitted, it replaces with the shielding plates W and W of Fig.3 (a),

flat part

5a, 5b (refer FIG. 2). ) May be masked with a tape or the like, and after forming the convex portion 51, an unnecessary coating layer attached to the tape may be peeled off together with the masking. Further, a mold having a surface shape of the coat layer 5 including the convex portion 51 is produced, and the material of the coat layer 5 is filled between the catalyst carrier 2 and the mold placed in the mold, and the coat layer 5 is formed. The convex portion 51 may be integrally formed.

Next, an assembly method of the catalytic converter 1 will be described with reference to FIG. FIG. 4 is an explanatory view of a method for assembling the catalytic converter.
As shown in FIG. 4A, first, the side surface holding member 4 is fitted into the outer peripheral surface of the catalyst carrier 2, and the side surface holding member 4 is disposed at a portion corresponding to the convex portion 51 of the catalyst carrier 2. At this time, since the side surface holding member 4 has elasticity, the side surface holding member 4 is deformed so as to conform to the surface shape of the convex portion 51.
Then, the catalyst carrier 2 and the side surface holding member 4 are inserted into the cylindrical metal case 3.

Next, as shown in FIG. 4B, the metal case 3 is rotated with the catalyst carrier 2 and the side surface holding member 4 disposed therein, and the rollers R and R of the spinning machine are moved to the surface of the metal case 3. The roller R is moved in the axial direction while pressing the metal case 3. Then, the diameter of the metal case 3 is reduced in accordance with the surface shape of the coat layer 5 by adjusting the distance between the rollers R and R according to the surface shape of the coat layer 5 (that is, the surface shape of the convex portion 51).
Thereby, the holding part 3c corresponding to the convex part 51 of the coat layer 5 in the metal case 3 is in a state of bulging toward the outer side in the radial direction in a ring shape and in a cross-sectional view along the circumferential direction. Become. Therefore, the convex portion 51 of the catalyst carrier 2 is held immovably in the axial direction and the radial direction by the holding portion 3 c corresponding to the convex portion 51 of the metal case 3 via the side surface holding member 4.

Next, the rollers R, R of the spinning machine are applied to the upstream portion 3d of the metal case 3 on the upstream side of the catalyst carrier 2, and the metal case 3 is reduced in diameter to approximately the same diameter as the catalyst carrier 2. In this way, the spinning of the metal case 3 completes the assembly of the catalytic converter 1.

According to the carrier holding structure of the catalytic converter 1 configured as described above, the following operational effects can be obtained.
In the catalytic converter 1, a convex portion 51 is formed along the circumferential direction on the coat layer 5 covering the outer peripheral surface of the catalyst carrier 2, and the catalyst carrier is interposed via the side surface holding member 4 disposed outside the convex portion 51. Since the position 2 is fixed to the metal case 3, the cross-sectional area of the catalyst carrier 2 does not decrease as in the prior art, and a decrease in exhaust efficiency can be suppressed. Moreover, since the convex part 51 is formed in the coat layer 5, a member intensity | strength does not fall like the past, and the crack of the catalyst carrier 2, etc. can be prevented.

Moreover, since the coat layer 5 is thickened by forming the convex portions 51 and the strength of the catalyst carrier 2 is improved, the thickness of the side surface holding member 4 can be reduced to increase the surface pressure and increase the holding force. . Thereby, the catalyst carrier 2 can be held in the axial direction and the radial direction by the side surface holding member 4. Therefore, it is possible to omit an end holding member (not shown) that has been conventionally installed at the upstream and downstream end peripheral edges of the catalyst carrier 2 as necessary, and the thickness of the side holding member 4 can be reduced. Since the number of parts can be reduced, the number of parts can be reduced and the weight can be reduced, and the side surface holding member 4 can be easily attached.

Moreover, since the convex part 51 can be formed by thickly coating the coat layer 5, it can respond in the production process of the coat layer 5, and the convex part 51 can be easily formed without complicating the manufacturing work. be able to.

Further, since the diameter of the metal case 3 is reduced by spinning processing in accordance with the surface shape of the convex portion 51, the catalyst carrier 2 is placed in the metal case 3 with a predetermined surface pressure while suppressing the displacement of the side surface holding member 4. The metal case 3 can be easily processed so that it can be held.

Further, the length L1 of the convex portion 51 in the axial direction of the catalyst carrier 2 is 0.3 to 1.0 times the axial length L2 of the catalyst carrier 2 itself. If D1 is configured to be 1.01 to 1.2 times the outer diameter D2 of the portion not including the convex portion 51 of the catalyst carrier 2, the catalyst carrier 2 is reduced while reducing the area of the side surface holding member 4. It is possible to obtain a sufficient strength that does not affect the cell 21 of the catalyst carrier 2 while having a contact area that can be sufficiently retained and holding the catalyst carrier 2 on the side surface.

Further, since the plurality of grooves 53a are formed in the circumferential direction on the outer peripheral surface of the convex portion 51, the contact area between the side surface holding member 4 and the convex portion 51 increases, and the frictional force increases. Therefore, the holding force of the catalyst carrier 2 by the side surface holding member 4 can be improved.

Next, the carrier holding structure of the catalytic converter 1 according to the second embodiment will be described with reference to FIG. In the description, the same elements as those of the first embodiment are denoted by the same reference numerals, and redundant description is omitted.

FIG. 5 is a cross-sectional view of a main part of the catalytic converter according to the second embodiment. Note that the arrow f in FIG. 5 indicates the flow direction of the exhaust gas.
The carrier holding structure of the catalytic converter 1 according to the second embodiment is different from the first embodiment described above in that an annular recess 62 is provided on the outer peripheral surface of the protrusion 61 formed in the coat layer 5. ing. That is, in the second embodiment, the holding portion 3c and the side surface holding member 4 which are portions corresponding to the convex portion 61 of the metal case 3 enter the recess 62, thereby holding the catalyst carrier 2 in the axial direction and the radial direction. is doing.

The recess 62 is formed in a substantially V shape in cross-sectional view, and the upstream side and the downstream side of the recess 62 relatively constitute projecting

portions

63 and 63.
The diameter of the metal case 3 is reduced according to the surface shape of the recess 62 and the

protrusions

63 and 63 by spinning. Further, the side surface holding member 4 is also deformed so as to conform to the surface shape of the recess 62 and the

protrusions

63 and 63 due to the reduced diameter of the metal case 3.
In addition, in the metal case 3, the upstream portion 3 d on the upstream side of the catalyst carrier 2 and the downstream portion 3 e on the downstream side are reduced in diameter to approximately the same diameter as the outer diameter of the catalyst carrier 2.
The outer peripheral edge on the upstream side and the outer peripheral edge on the downstream side of the catalyst carrier 2 are not in contact with the metal case 3.

According to such a configuration, since the metal case 3 and the side surface holding member 4 enter the recess 62 formed in the convex portion 61, the metal case 3 is axially aligned even when the metal case 3 is thermally expanded in the radial direction. And the inclined surface of the recess 62 (or the projecting portions 63 and 63) is pressed radially inward via the side surface holding member 4, so that the holding force of the catalyst carrier 2 by the metal case 3 is increased. The decrease can be suppressed.

Next, the carrier holding structure of the catalytic converter 1 according to the third embodiment will be described with reference to FIG. In the description, the same elements as those of the first embodiment are denoted by the same reference numerals, and redundant description is omitted.

FIG. 6 is a cross-sectional view of a main part of the catalytic converter according to the third embodiment. In addition, the arrow f of FIG. 6 has shown the flow direction of waste gas.
The carrier holding structure of the catalytic converter 1 according to the third embodiment includes

end holding members

8 and 9 that come into contact with the upstream end 72 and the downstream end 73 of the convex portion 71 formed in the coat layer 5. This is different from the first and second embodiments described above.

In 3rd Embodiment, the outer peripheral surface of the convex part 71 is formed flat, and the side surface holding member 4 is installed in the circumference | surroundings. In the third embodiment, the length dimension of the convex portion 71 in the axial direction is about 0.3 to 0.9 times the length dimension of the catalyst carrier 2 in the axial direction.
Further,

end holding members

8 and 9 which are wire mesh rings formed in an annular shape using a metal fiber or the like are installed facing the upstream end 72 and the downstream end 73 of the convex portion 71. .
Of the metal case 3, the holding portion 3 c which is a portion corresponding to the convex portion 71 is reduced in diameter by spinning processing in accordance with the surface shape of the convex portion 71. Thereby, the catalyst carrier 2 is held by the metal case 3 so as not to move in the radial direction via the side surface holding member 4.
In addition, in the metal case 3, the upstream portion 3 d on the upstream side of the catalyst carrier 2 and the downstream portion 3 e on the downstream side are reduced in diameter to approximately the same diameter as the outer diameter of the catalyst carrier 2.
The outer peripheral edge on the upstream side and the outer peripheral edge on the downstream side of the catalyst carrier 2 are not in contact with the metal case 3.

And the taper part 3f which connects the holding | maintenance part 3c and the upstream part 3d among the metal cases 3 is formed so that it may become a small diameter, so that it goes upstream. The inner peripheral surface of the taper portion 3f is in contact with the upstream end of the upstream end holding member 8, and restricts the end holding member 8 and the catalyst carrier 2 from moving upstream.
Moreover, the taper part 3g which connects the holding | maintenance part 3c and the downstream part 3e among the metal cases 3 is formed so that it may become a small diameter, so that it goes downstream. The inner peripheral surface of the taper portion 3g is in contact with the downstream end of the downstream end holding member 9, and restricts the end holding member 9 and the catalyst carrier 2 from moving downstream.

According to the carrier holding structure of the catalytic converter 1 according to the third embodiment, the

end holding members

8 and 9 are mounted in addition to the side holding member 4 and are directly fixed by the metal case 3. The side and end portions of the catalyst carrier 2 can be held only by spinning, and workability is improved.
Further, since the upstream end and the downstream end of the catalyst carrier 2 are not in contact with the metal case 3 and the

end holding members

8 and 9, no load is applied when the catalytic converter 1 vibrates. Therefore, cracking of the catalyst carrier 2 can be prevented.

As mentioned above, although embodiment of this invention was described in detail with reference to drawings, this invention is not limited to this, In the range which does not deviate from the main point of invention, it can change suitably.

For example, in the present embodiment, only one

convex portion

51, 61, 71 is formed in a ring shape at the central portion in the axial direction of the coat layer 5 of the catalyst carrier 2, but the present invention is not limited to this. For example, you may form a some convex part at intervals in the axial direction. Moreover, the convex part 51 does not need to be annular.

In the present embodiment, the diameter of the metal case 3 is reduced by spinning, but the present invention is not limited to this. For example, although not shown, the cylindrical metal case 3 is divided in half in the axial direction to form two halved members, which are pressed according to the surface shape of the coat layer 5 of the catalyst carrier 2. Alternatively, after the catalyst carrier 2 and the side surface holding member 4 are disposed inside, the two half-shaped members may be welded to form the cylindrical metal case 3.
Further, the diameter of the metal case 3 may be reduced using a split mold or an integrated mold.

In the present embodiment, the plurality of grooves 53a are formed along the circumferential direction on the surface of the convex portion 51. However, the present invention is not limited to this, and for example, a granular material is applied to the surface of the tapered portion 53. It is only necessary to roughen the surface of the convex portion 51 and increase the friction with the side surface holding member 4 by a method such as spraying.

In the present embodiment, the catalyst carrier 2 of the catalytic converter 1 has been described as an example of the honeycomb structure in the exhaust gas purifying apparatus. However, the present invention is not limited to this, for example, a honeycomb as a filter in a DPF. It may be a structure.

1 Catalytic converter (exhaust gas purification device)
2 Catalyst carrier (honeycomb structure)
3 Metal Case 4 Side Surface Holding Member 5 Coat Layer 51 Projection

Claims

A honeycomb structure holding structure in an exhaust gas purification device disposed in an exhaust passage,
A honeycomb structure having a plurality of cells and having an outer peripheral surface covered with a coat layer;
A metal case for holding the honeycomb structure inside;
A side surface holding member interposed between the honeycomb structure and the metal case,
The coat layer has a convex portion at least partially along the circumferential direction,
The honeycomb structure holding structure in an exhaust gas purifying apparatus, wherein the honeycomb structure is fixed to the metal case via the side surface holding member disposed outside the convex portion.
The convex portion is configured by making the coat layer thicker than other portions,
The coat layer is made of a material containing at least one selected from the group consisting of ceramics, alumina, mullite, lithium aluminum silicate, silicon carbide, silicon nitride, alumina titanate, and cordierite. A holding structure for a honeycomb structure in the exhaust gas purifying apparatus according to claim 1.
2. The catalyst according to claim 1, wherein the metal case is reduced in diameter by a diameter reduction process in accordance with a surface shape of the convex portion, and the side surface holding member is fixedly held at a predetermined pressure. Converter carrier holding structure.
The length of the convex portion in the axial direction of the honeycomb structure is 0.3 to 1.0 times the length of the honeycomb structure itself in the axial direction, and the outer diameter of the convex portion is The retention of the honeycomb structure in the exhaust gas purifying apparatus according to claim 1, wherein the honeycomb structure has an outer diameter of 1.01 to 1.2 times an outer diameter of a portion not including the convex portion. Construction.
A part of the convex part formed by the coat layer is depressed to further form a concave part, the side surface holding member is attached to the outer peripheral surface of the convex part of the honeycomb structure including the concave part, The honeycomb structure holding structure in the exhaust gas purifying apparatus according to claim 1, wherein the diameter of the metal case is reduced in accordance with a surface shape of the convex portion including a recess.
A plurality of protrusions are further formed on the surface of the protrusions formed by the coat layer at intervals in the axial direction, and the outer peripheral surface of the protrusions of the honeycomb structure including the plurality of protrusions is The honeycomb structure according to claim 1, wherein a side surface holding member is attached and the diameter of the metal case is reduced in accordance with a surface shape of the convex portion including the protruding portion. Holding structure.
An end holding member that restricts movement of the honeycomb structure in the axial direction is disposed at a position facing the upstream end and the downstream end of the convex portion formed of the coat layer, and the end The honeycomb in the exhaust gas purification apparatus according to claim 1, wherein the diameter of the metal case is reduced so as to apply a predetermined pressure in an axial direction to an upstream end and a downstream end of the portion holding member. Structure holding structure.
The honeycomb structure holding structure in an exhaust gas purification apparatus according to claim 1, wherein a plurality of grooves are formed on the outer peripheral surface of the convex portion.