JP3580474B2 - Monolithic catalytic converter and manufacturing method thereof - Google Patents

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a monolithic catalytic converter used for purifying exhaust gas from automobiles and the like, and a method for manufacturing the same.
[0002]
[Prior art]
Catalytic converters used for purifying exhaust gas from automobiles are very good after-treatment devices compared to other exhaust gas treatment systems, so that the engine itself does not have to be overburdened, and fuel efficiency and driving performance are low. The exhaust gas can be cleaned without dropping. The catalytic converter includes a pellet catalytic converter and a monolith catalytic converter depending on the shape of the catalyst. Among these catalytic converters, monolithic catalytic converters are widely used because they have a smaller heat capacity than pellet catalytic converters and thus have excellent warm-up performance and also have a small pressure loss.
[0003]
The monolithic catalytic converter holds an integrally formed monolithic catalyst in a catalyst container. This catalyst container is connected to an exhaust gas pipe, and exhaust gas discharged from an engine is guided to the monolith catalyst. To purify harmful components.
As a conventional monolithic catalytic converter, for example, there is a monolithic catalytic converter including a catalytic container in which an upper case and a lower case are integrally joined, and a monolithic catalyst held in the container. In this catalytic converter, a flange is formed on the entire periphery of the mating surface of the upper case and the lower case, and the two case flanges are joined by welding or the like while holding the monolith catalyst inside the two cases. It is something that can be done.
[0004]
As another monolithic catalytic converter, there is a catalytic converter described in Japanese Patent Application Laid-Open No. 9-112259. This monolithic catalytic converter is a catalytic converter comprising a cylindrical main body holding a monolithic catalyst inside, and a funnel-shaped cone formed integrally at both ends of the main body. In addition, this monolithic catalytic converter fixes the raw tube in which the monolithic catalyst is inserted to a chuck, draws a roller by applying a roller to this raw tube while rotating the raw tube, so that it is symmetrical about the rotation axis. It was manufactured in one piece.
[0005]
[Problems to be solved by the invention]
However, in a monolithic catalytic converter using a catalyst container in which two cases are welded, the catalyst container is welded and joined in a state where flanges formed on a mating surface of an upper case and a lower case are in contact with each other. In addition, the heat generated during the welding may cause distortion of the container, which may impair the assemblability to the exhaust gas pipe. Further, the flow of the exhaust gas is disturbed by the joint between the two cases, and the turbulence may increase the exhaust resistance and reduce the output of the engine. Furthermore, if the welding at the mating surface of the two cases is insufficient, exhaust gas leakage occurs, so inspections such as a leak test are performed, and this inspection is troublesome and costly.
[0006]
Further, the catalytic converter described in Japanese Patent Application Laid-Open No. Hei 9-112259 is obtained by subjecting both ends of a pipe to a drawing process, so that the catalyst container itself has no joint. For this reason, gas leakage from the catalyst container does not occur, and an inspection such as a leak test is not required. However, this catalytic converter is drawn by drawing both ends of the pipe along the central axis, and it is necessary to connect the exhaust gas pipe to the central axis of the catalytic converter in the vicinity of the connection with the exhaust gas pipe to be connected. A large space was required for joining and arranging the catalytic converter and the exhaust gas pipe. That is, since the arrangement of the exhaust gas pipe is limited, the degree of freedom in design is reduced.
[0007]
The present invention has been made in view of the above circumstances, and provides a monolithic catalytic converter having a high degree of freedom in design such that an inspection such as a leak test is not required and the arrangement of exhaust gas pipes is not limited, and a method for manufacturing the same. As an issue.
[0008]
[Means for Solving the Problems]
In order to solve the above-mentioned problems, the present inventors have repeatedly studied a catalyst container that holds a monolith catalyst inside, and as a result, the catalyst container itself does not have a joint portion in the axial direction and the circumferential direction, and the catalyst container holds the monolith catalyst inside. A monolithic catalytic converter that solves the above problem by using a catalytic converter using a catalyst container in which a central axis of a main body portion to be shifted and a central axis of a side end portion for connecting the main body portion to an exhaust gas pipe are eccentric. Can be provided.
[0009]
That is, monolithic catalyst converter according to the present invention comprises a catalyst container connected to the exhaust pipe, and rod-shaped monolith catalysts both end faces held in the catalyst container is perpendicular to the axial direction, the monolithic catalyst converter comprising a catalyst The container has a cylindrical main body part whose both ends holding the monolith catalyst inside are orthogonal to the axial direction, and is formed integrally with the main body part at both ends of the main body part. a central shaft and a main body portion side end portion center axis shaped funnel eccentrically offset of joining end to be joined with the tube, Ri Tona, inner diameter end of the body portion is formed thinner than the inner diameter of the body portion It is characterized in that it has a catalyst holding part and the catalyst container does not have a joint part .
[0010]
Further, the method for manufacturing a monolithic catalytic converter of the present invention includes an inserting step of inserting a monolithic catalyst into a tubular pipe material, a step of fixing the pipe material having the monolithic catalyst to a chuck portion of a spattling machine, In the radial direction between the rotation center of the chuck part and the processing roller, the processing roller is slightly inside the outer circumference of the pipe material while giving relative rotation between the processing part and the processing roller of the spatula drawing machine. With the distance kept constant, the spatula was drawn between the open end of the pipe material and the end of the main body, and the radial distance between the center of rotation of the chuck portion and the processing roller was reduced in sequence to reduce the distance. Drawing is performed between the open end of the drawn pipe material and a portion slightly away from the end of the main body to form a funnel-shaped outer end that is eccentric with the center axis of the main body shifted. And having a et drawing step.
Further, the method for producing a monolithic catalytic converter of the present invention is characterized in that a round rod-shaped monolithic catalyst, a cylindrical main body having both ends for holding the monolithic catalyst therein orthogonal to the axial direction, and both ends of the main body are integrated with the main body. A catalyst container consisting of a funnel-shaped side end that is eccentric with the center axis of the joint end that is formed at the end of the main body and whose inner diameter is shortened from the end of the main body and is joined to the exhaust gas pipe and the center axis of the main body is shifted and eccentric A method of manufacturing a monolithic catalytic converter, comprising: inserting a monolithic catalyst into a tubular pipe material; fixing a pipe material having a monolithic catalyst to a chuck of a spatula processing machine; The center of rotation of the chuck section and the processing roller so that the processing roller is slightly inside the outer circumference of the pipe material while giving relative rotation between the processing roller of the spatula drawing machine. The radial distance to the spatula drawing between the end portion of the open end and the body portion of the pipe material while the constant radial distance between sequential chuck portion of the rotation center and the processing rollers in A funnel-shaped outer end that is eccentric, with the center axis of the main body shifted and eccentric, between the open end of the pipe material that has already been drawn while shortening and the part slightly away from the end of the main body And a spatula drawing process for forming a spatula , wherein the spatula drawing process is performed by rotating the pipe material in an eccentric state so that the rotation center of the chuck portion coincides with the center axis of the processing circle to be spatulated. It is characterized in that it is a step of drawing with a spatula .
[0011]
BEST MODE FOR CARRYING OUT THE INVENTION
(Monolith catalytic converter)
In the monolithic catalytic converter of the present invention, the catalyst container holding the monolithic catalyst therein is eccentric with the center axis of the main body holding the monolithic catalyst inside and the center axis of the joining end joined to the exhaust gas pipe. It has a side end.
[0012]
The catalyst container has a cylindrical main body having both ends for holding the monolithic catalyst therein at right angles to the axial direction, and is formed integrally with the main body at both ends of the main body, and has an inner diameter shortened from the end of the main body. A central axis of a joint end to be joined to the exhaust gas pipe and a funnel-shaped side end part eccentric with the central axis of the main body part shifted. This catalyst container has a body portion and a side end portion integrally formed, and does not have a joint such as a welded portion in an axial direction, a radial direction, and a circumferential direction. As a material used for the catalyst container, a material formed by molding a stainless steel pipe is preferable.
[0013]
The main body has a cylindrical shape with both ends orthogonal to the axial direction, and holds the monolith catalyst inside. The main body has a cylindrical shape having an inner diameter that matches the outer periphery of the round bar-shaped monolith catalyst.
The side end is formed in a funnel shape in which the inner diameter is shortened from the end of the main body, and the center axis of the joint end to be joined to the exhaust gas pipe and the center axis of the main body are shifted and eccentric. In the side end, the center axis in a cross section perpendicular to the axial direction is shifted from the center axis of the main body. Further, the side end is formed so that the inner diameter becomes shorter from the end of the main body, and is formed so as not to coincide with the axial extension of the main body.
[0014]
The catalyst container is preferably formed by molding a tubular pipe material. Even if this pipe material has no joints or an axial seam formed by rolling a plate-shaped material into a cylindrical shape and joining it, the joint portion of the catalyst container is generally similar to a commercially available material. Any material that does not impair airtightness can be used.
As the monolith catalyst, one having both ends formed in a round bar shape perpendicular to the axial direction is used. As the monolith catalyst, those used in a normal monolith catalytic converter are used. That is, a ceramic carrier is used as a carrier substrate, a ceramic catalyst supporting layer is formed on the ceramic carrier, and a catalyst metal such as platinum is supported on the catalyst supporting layer. In addition, a metal carrier in which a honeycomb body in which a corrugated plate and a flat plate are wound is held in an outer cylinder can be used as a carrier base material of a monolithic catalyst.
[0015]
The monolith catalyst is wound with a monolith sealing material. As the monolithic sealing material, vermiculite having thermal expansion properties, a material made of a ceramic fiber having high heat resistance and maintained in a sheet shape by a binder, or an alumina mat can be used. Thus, the change in the gap between the catalyst container and the catalyst surface, which occurs under cold and hot conditions, is ensured, the catalyst is held and fixed, and the exhaust gas is prevented from leaking.
[0016]
The main body preferably has a catalyst holding portion in which the inner diameter of the end is smaller than the inner diameter of the main body. The narrow end holds the outer peripheral surface of the monolith catalyst inserted into the main body, and prevents the monolith catalyst from shifting in the axial direction and being broken.
(Method of manufacturing monolithic catalytic converter)
The manufacturing method of the monolithic catalytic converter according to the present invention includes the steps of: inserting a monolithic catalyst into a tubular pipe material; fixing the pipe material to a chuck of a drawing machine; And a spatula drawing step for forming a funnel-shaped outer end portion which is eccentric.
[0017]
The insertion step is a step of inserting a round bar-shaped monolith catalyst into a tubular pipe material.
The step of fixing to the chuck portion is a step of fixing the pipe material into which the monolith catalyst has been inserted to the chuck of the spatula processing machine.
The spatula drawing process is performed by rotating the chuck unit and the processing roller so that the processing roller is slightly inside the outer periphery of the pipe material while giving relative rotation between the chuck unit and the processing roller of the spatula processing machine. While keeping the radial distance between them constant, the space between the open end of the pipe material and the end of the main body part is drawn down, and the radial direction between the rotation center of the chuck part and the processing roller is successively formed. While shortening the distance, the drawing process is performed between the open end of the pipe material that has already been drawn and the part slightly away from the end of the main body, and the center axis of the main body is shifted and the funnel-shaped outside is eccentric This is a step of forming an end.
[0018]
In this spatula drawing step, relative rotation is given between the chuck portion for fixing the pipe material and the processing roller. Here, the relative rotation given between the chuck portion and the processing roller is given by rotation of the chuck portion or the processing roller, and the processing roller can be brought into contact with the entire outer peripheral surface of the pipe material. Is given to The rotation center at this time preferably coincides with the center axis of the pipe material.
[0019]
In addition, the spatula drawing in the spatula drawing process is such that when the processing roller moves between the open end of the pipe material and the end of the main body, the amount of the pipe material that is radially squeezed is small. This is done by the rollers moving many times. Here, the movement of the processing roller indicates that the processing roller moves in a state slightly inside the outer periphery of the pipe material.
[0020]
The repetition of the movement of the processing roller may be any of repetition of one-way movement between the open end and the main body, or movement of reciprocating between the open end and the main body. That is, the movement of the processing roller in the manufacturing method of the present invention is a method in which the processing roller repeats moving in the direction from the open end of the pipe material to the main body, or moving in the direction from the main body to the open end. The movement may be in any direction, such as a repetition method or a movement in which reciprocation is repeated between the open end and the main body.
[0021]
The spatula drawing step in the manufacturing method of the present invention is a step of spinning while rotating the pipe material in an eccentric state so that the rotation center of the chuck portion coincides with the center axis of a processing circle to be spatulated. Is preferred. That is, the chuck portion may be rotated in a state where the rotation center of the chuck portion does not coincide with the center axis of the pipe material, and may be subjected to spatula drawing. In this case, when ordinary spinning drawing is performed, the end of the main body does not become perpendicular to the axial direction, and the end becomes inclined, so that a useless space is formed between the end and the end face of the monolith catalyst, Waste of weight, cost, and heat capacity occurs. For this reason, it is important to control the movement of the processing roller and the pipe material in the radial direction.
[0022]
The spatula drawing step in the production method of the present invention is preferably performed by a spinning drawing apparatus.
The spinning drawing apparatus has a configuration shown in the schematic diagram of FIG. That is, the present apparatus is provided so that the chuck can hold the pipe material with one end opening of the pipe material protruding horizontally, and this chuck is connected to the rotation shaft of the motor, whereby the pipe material is rotated. It is rotatable around. The chuck is movable by a hydraulic cylinder in a vertical direction, which is a direction perpendicular to the rotation axis of the pipe material. Above one end opening of the pipe material, there is provided a vertically movable table which can be vertically moved by a hydraulic cylinder, and this vertically movable table can be horizontally moved in a direction in which a rotation axis extends by a hydraulic cylinder. A horizontal carriage is provided. A processing roller is provided on the horizontal moving table by a bracket so as to be driven. This processing roller has a U-shaped cross section.
[0023]
In a manufacturing method using the present apparatus, first, a pipe material into which a monolith catalyst is inserted is fixed to a chuck of the drawing machine. Subsequently, the chuck and the pipe material linked to the motor are rotated by rotating the motor. Then, while pressing the processing roller against the open end of the rotated pipe material and moving the horizontal moving table in the horizontal direction toward the base end side while also moving it vertically, the chuck is moved vertically by the hydraulic cylinder. The pipe material is drawn into an eccentric funnel. Here, since the amount of squeezing processed by one movement of the processing roller is limited, the side end is formed by moving the processing roller many times.
[0024]
【Example】
Hereinafter, the monolithic catalytic converter of the present invention and a method for manufacturing the same will be described using examples.
(Example 1)
This embodiment is a monolithic catalytic converter shown in FIGS. 1 and 2 and includes a catalyst container 1 made of stainless steel and a monolithic catalyst 3 held in the catalyst container 1.
[0025]
The monolithic catalyst 3 has a ceramics carrier supporting layer formed on the surface of a ceramics carrier, and a catalyst metal is carried on the catalyst supporting layer. The monolithic catalyst 3 is formed in a round rod shape having a diameter of 129 mm and an axial length of 150 mm. Is used. The monolithic catalyst has a ring-shaped holding member (not shown) formed by accumulating stainless steel fibers having a coefficient of thermal expansion larger than that of stainless steel used for the catalyst container on a peripheral surface on one end side, and a central peripheral surface. A monolith sealing material (not shown) made of ceramic fiber and vermiculite is wound. At this time, an alumina mat may be used as the monolith sealing material.
[0026]
The catalyst container 1 is formed by molding a stainless steel pipe having a diameter of 140 mm and a thickness of 1.5 mm. In this catalyst container, a main body 11 having an axial length of 150 mm and eccentric funnel-shaped side ends 13 having an axial length of 86 mm are formed at both ends of the main body 11.
The inner diameter of the side end 13 is gradually reduced so that the inner diameter of the joint end 15 side with the exhaust gas pipe becomes shorter so that the main body 11 of the catalyst container 1 and the exhaust gas pipe having a smaller diameter than the main body can be connected. In addition, the center axis of the pipe forming the main body 11 and the center axis of the joint end with the exhaust gas pipe are shifted by 35 mm. The joining ends 15 of the side end portions 13 are opened at symmetrical positions at both ends of the main body portion 11. That is, as shown in FIG. 2, the extension of the central axis of the two side end portions 13 formed at both ends of the main body portion 11 is formed so as not to overlap.
[0027]
In the monolithic catalytic converter of the present embodiment, since the end portion 12 of the main body portion 11 holding the monolithic catalyst 3 is orthogonal to the axial direction, no useless space is formed in the catalyst container 1 and the weight is small and the heat capacity is small. ing. Further, since the joint end 15 is not formed on an extension of the central axis of the main body 11, it can be freely adjusted to the pipe path.
(Manufacture of monolith catalytic converter)
The monolithic catalytic converter is manufactured by inserting a monolithic catalyst into a stainless steel pipe formed in a catalyst container and then drawing the pipe by a spinning drawing apparatus. Here, the spinning drawing apparatus has a structure shown in the schematic diagram of FIG. That is, a chuck 51 that rotates in conjunction with a motor 52, a hydraulic cylinder 53 that moves the chuck 51 in the vertical direction, a processing roller 61 that deforms the pipe 10 attached to the chuck 51, And a hydraulic cylinder 62 that moves in the radial direction.
[0028]
That is, first, a monolithic catalyst 3 previously formed into a round rod shape having a diameter of 129 mm and a length of 140 mm in the axial direction in which a holding member and a monolithic sealing material are wound around the peripheral surface is formed into a catalyst container 1. It was inserted into a stainless steel pipe 10 having a thickness of 137 mm and a thickness of 1.5 mm. This pattern is shown in FIG.
Subsequently, one end of the stainless steel pipe in which the monolith catalyst is held is fixed to the chuck 51 of the spinning drawing apparatus so that the central axis of the pipe 10 is held horizontally. The chuck 51 used for the fixing is connected to a rotation shaft of a motor 52, and the chuck 51 also rotates in conjunction with the rotation of the motor 52.
[0029]
Next, with the stainless steel pipe 10 fixed to the chuck 51, the motor 52 is rotated at 700 rpm. With the rotation of the motor 52, the chuck 51 connected to the motor 52 rotates. A processing roller 61 was pressed against the tip of the rotating pipe 10 to be processed into the joint end 15 of the side end 13 with the exhaust gas pipe, and spatula drawing was performed to deform the pipe 10. The processing roller 61 pressed against the pipe 10 moves from the open end of the pipe 10 toward the chuck 51, and moves by the hydraulic cylinder 53 in a vertical direction away from the center axis of the pipe 10. The pipe 10 also moves in the vertical direction with the movement of the processing roller 61. By repeating this movement of the processing roller 61 and the pipe 10, the pipe 10 is gradually drawn. Here, the center axis of the pipe 10 and the rotation axis of the chuck 51 match. The movement of the processing roller was performed by controlling the bracket to which the processing roller was attached by the hydraulic cylinder 62. This pattern is shown in FIG.
[0030]
This drawing was performed on the openings at both ends to obtain a monolithic catalytic converter having side ends with controlled eccentricity formed at both ends. By using this production method, a monolithic catalytic converter can be obtained by one molding, so that it is not necessary to change the steps or prepare a large number of molding machines, and it is possible to reduce the time and cost required for production.
Further, in the method for manufacturing a monolithic catalytic converter of the present invention, as shown in FIG. 6, even if the rotation axis of the chuck 51 to which the stainless steel pipe 10 is fixed is shifted, the movement of the roller 61 and the control of the processing roller 61 are controlled. Thereby, the eccentric side end can be processed.
[0031]
Further, as another method for manufacturing a monolithic catalytic converter, as shown in FIG. 7, the processing roller moves in the vertical and horizontal directions while rotating on the outer periphery of the pipe, and the chuck moves in the vertical direction, and the spatula is drawn. By performing the processing, the eccentric side end can also be processed.
Another embodiment of the monolithic catalytic converter of the present invention will be described below.
[0032]
(Example 2)
As shown in FIG. 8, this embodiment is the same as the first embodiment except that the end 12 of the main body is formed thin and the main body 11 and the side end 13 are integrally formed. It is a monolithic catalytic converter. That is, the main body 11 of this embodiment is a stainless steel pipe having an axial length of 150 mm, a diameter of 140 mm, and a thickness of 1.5 mm, and the end 12 of the main body is formed to be thin so that the inner diameter is 137 mm. It was done. In addition, the end portion 12 of the thin main body portion holds and fixes the monolith catalyst 3 via a monolith sealing material 31.
[0033]
The production of the monolithic catalytic converter of the present embodiment is performed by pressing the processing roller of the drawing device in the central axis direction at the opening end of the stainless steel pipe while rotating the stainless steel pipe holding the monolithic catalyst inside, and in the vertical direction. By moving the pipe in the vertical direction while shifting it in the horizontal direction, the drawing was performed by drawing to form the side end and the end of the thinly formed main body.
[0034]
In this embodiment, since the end of the main body is formed thinner than the main body, the monolith catalyst in the main body can be prevented from being shifted in the axial direction of the main body. The loss can be suppressed.
[0035]
【The invention's effect】
In the monolithic catalytic converter of the present invention, since the center axis of the joining end between the monolithic catalyst and the exhaust gas pipe is deviated and eccentric, it can be joined to a curved portion of the exhaust gas pipe. Can be reduced. In addition, the exhaust system as a whole can avoid interference with the body and limit the height above the ground. That is, the monolithic catalytic converter of the present invention has the effect of reducing the space for joining with the exhaust gas pipe and increasing the degree of freedom in design.
[Brief description of the drawings]
FIG. 1 is a perspective view of a monolithic catalytic converter according to a first embodiment.
FIG. 2 is a cross-sectional view of the monolithic catalytic converter according to the first embodiment.
FIG. 3 is a schematic diagram showing a configuration of a spinning drawing apparatus.
FIG. 4 is a diagram in which a monolith catalyst is inserted into a stainless steel pipe.
FIG. 5 is a drawing of drawing by a spinning drawing apparatus.
FIG. 6 is a drawing of a drawing process when a rotation axis of a pipe is shifted.
FIG. 7 is a drawing of a drawing process when a processing roller rotates around the outer circumference of a pipe.
FIG. 8 is a sectional view of a monolithic catalytic converter according to a second embodiment.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 ... Catalyst container 10 ... Pipe 11 ... Body part 12 ... End part of a body part 13 ... Side end part 3 ... Monolith catalyst 31 ... Monolith seal material 51 ... Chuck 52 ... Motor 53 ... Hydraulic cylinder 61 ... Roller 62 ... Hydraulic cylinder

Claims (2)

In a monolithic catalytic converter comprising a catalyst container connected to the exhaust gas pipe and a round bar-shaped monolithic catalyst whose both end faces held in the catalyst container are orthogonal to the axial direction,
The catalyst container has a cylindrical main body having both ends that hold the monolith catalyst therein, and a cylindrical main body that is formed integrally with the main body at both ends of the main body. a funnel-shaped side edge portion central axis is eccentric offset of the central axis and the body portion of the bonding end inner diameter is joined with shorter becomes the exhaust gas pipe, Tona is, the inner diameter of the end portion of the body portion A monolithic catalytic converter having a catalyst holding portion formed thinner than the inner diameter of the main body, and wherein the catalyst container has no joint . A round rod-shaped monolithic catalyst, both ends of which hold the monolithic catalyst inside, a cylindrical main body orthogonal to the axial direction, and both ends of the main body formed integrally with the main body and ends of the main body Production of a monolithic catalytic converter composed of a central axis of a joint end to be joined to the exhaust gas pipe having a reduced inner diameter and a catalyst container having a funnel-shaped side end eccentric with the central axis of the main body portion shifted. The method,
An insertion step of inserting a monolith catalyst into a tubular pipe material,
Fixing the pipe material having the monolithic catalyst to a chuck portion of a spatula drawing machine;
The center of rotation of the chuck portion and the working portion are set so that the working roller is slightly inside the outer periphery of the pipe material while giving relative rotation between the chuck portion and the working roller of the spatula drawing machine. While keeping the radial distance between the rollers constant, a spatula process is performed between the open end of the pipe material and the end of the main body, and sequentially between the rotation center of the chuck and the processing roller. While the distance in the radial direction of the pipe is shortened, drawing is performed between the open end of the pipe material that has already been drawn and the portion slightly away from the end of the main body, and the center axis of the main body is shifted. A spatula drawing process that forms a funnel-shaped outer end that is eccentric,
The spatula drawing step is a step of rotating the pipe material in an eccentric state so that the center of rotation of the chuck portion coincides with the center axis of a processing circle to be spatulated, and performing a spatula drawing process. A method for producing a monolithic catalytic converter.

Images