JP2000064832A - Monolithic catalytic converter and method of manufacturing the same - Google Patents

Abstract

(57) [Problem] To provide a monolithic catalytic converter having a high degree of freedom in design that does not require an inspection such as a leak test and does not limit the arrangement of exhaust gas pipes, and a method of manufacturing the same. SOLUTION: The monolithic catalytic converter of the present invention comprises a catalyst container 1 connected to an exhaust gas pipe, and a round bar-shaped monolithic catalyst 3 whose both end faces held in the catalyst container are orthogonal to the axial direction.
Wherein the catalyst container 1 is formed integrally with the main body at both ends of the main body, and a cylindrical main body 11 having both ends holding the monolith catalyst therein at right angles to the axial direction. And a center end of a joint end to be joined to the exhaust gas pipe whose inner diameter is shortened from an end portion 12 of the main body portion, and a funnel-shaped side end portion 13 eccentric with the center axis of the main body portion shifted. And INDUSTRIAL APPLICABILITY 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.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a monolith catalytic converter used for purification of exhaust gas from automobiles and the like and a method for manufacturing the same.

[0002]

2. Description of the Related Art A catalytic converter used for purifying exhaust gas from an automobile or the like is a post-treatment device which is extremely superior to other exhaust gas treatment methods, so that the engine itself does not have to be so burdened. The exhaust gas can be cleaned without reducing fuel consumption and driving performance. The catalytic converter includes a pellet catalytic converter and a monolith catalytic converter depending on the shape of the catalyst. Among these catalytic converters, the monolith catalytic converter is widely used because it has a smaller heat capacity than the pellet catalytic converter and thus is excellent in warm-up performance and has a small pressure loss.

A monolith catalytic converter holds a monolithic catalyst integrally formed in a catalyst container, the catalyst container is connected to an exhaust gas pipe, and exhaust gas discharged from an engine is guided to the monolith catalyst, and the monolith catalyst is connected. It purifies harmful components in exhaust gas. Some conventional monolith catalytic converters include, for example, a catalyst container in which an upper case and a lower case are integrally joined, and a monolith catalyst held in the container. This catalytic converter has a flange formed on the entire circumference of the mating surfaces of the upper case and the lower case, and the flanges of the two cases are joined together by welding etc. while the monolith catalyst is held inside these two cases. It is what is done.

As another monolith catalytic converter, there is a catalytic converter described in Japanese Patent Laid-Open No. 9-112259. This monolith catalytic converter is a catalytic converter including a tubular main body that holds a monolith catalyst therein, and funnel-shaped cones that are integrally formed at both ends of the main body. In addition, this monolith catalytic converter fixes the tube with the monolith catalyst inserted in the chuck, draws it by applying a roller to this tube while rotating the tube, and makes it symmetrical about the axis of rotation. It is manufactured integrally.

[0005]

However, in a monolith catalytic converter using a catalyst container in which two cases are welded, the catalyst container is in a state where the flanges formed on the mating surfaces of the upper case and the lower case are in contact with each other. They were welded and joined, and the heat generated during the welding sometimes caused the container to be distorted, impairing the assemblability to the exhaust gas pipe. In addition, the flow of the exhaust gas is disturbed by the joint between the two cases, and the exhaust resistance increases due to this disturbance, which may lead to a reduction in engine output. Furthermore, if welding is insufficient at the mating surfaces of the two cases, exhaust gas leakage occurs, so inspections such as leak tests are performed, and this inspection requires much labor and cost.

Further, since the catalytic converter described in Japanese Patent Application Laid-Open No. 9-112259 has a pipe that is drawn at both ends, the catalyst container itself has no joint. For this reason, gas leakage from the catalyst container does not occur, and there is no need for inspection such as a leak test.
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 portion 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. In other words, since the arrangement of the exhaust gas pipe is limited, the degree of freedom in design has been reduced.

The present invention has been made in view of the above circumstances, and provides a monolith catalytic converter having a high degree of freedom of design and a method of manufacturing the same, which does not require inspection such as a leak test and does not restrict the arrangement of exhaust gas pipes. The challenge is to provide.

[0008]

In order to solve the above problems, the present inventor has conducted extensive studies on a catalyst container holding a monolith catalyst therein, and as a result, the catalyst container itself has a joint portion in the axial direction and the circumferential direction. In addition, the central axis of the main body that holds the monolith catalyst inside and the central axis of the side end that connects the main body to the exhaust gas pipe should be a catalyst converter that uses an eccentric catalyst container. Have found that it is possible to provide a monolith catalytic converter that solves the above problems.

That is, the monolith catalytic converter of the present invention comprises a catalyst container connected to the exhaust gas pipe, and a rod-shaped monolith catalyst whose both end faces are held in the catalyst container and are orthogonal to the axial direction. In the catalyst container, both ends for holding the monolith catalyst inside are cylindrical main body portions orthogonal to the axial direction, and the main body portion is integrally formed with both ends of the main body portion from the end portion of the main body portion. It is characterized in that it has a funnel-shaped side end portion in which the center axis of the joint end, which has a smaller inner diameter and is joined to the exhaust gas pipe, and the center axis of the main body part are deviated from each other.

Further, the method of manufacturing a monolith catalytic converter according to the present invention comprises an inserting step of inserting the monolith catalyst into the tubular pipe material and a step of fixing the pipe material having the monolith catalyst to the chuck portion of the spatula drawing machine. And the relative rotation between the chuck part and the processing roller of the spatula drawing machine, the center of rotation between the chuck part and the processing roller should be adjusted so that the processing roller is slightly inside the outer circumference of the pipe material. Spatial processing is performed between the open end of the pipe material and the end of the main body while keeping the radial distance constant, and the radial distance between the rotation center of the chuck and the processing roller is shortened sequentially. In addition, the outer end of the funnel-shaped pipe material, which has already been drawn, is drawn between the open end of the pipe material and a portion slightly apart from the end of the main body, and the center axis of the main body is offset and eccentric. And having a spatula drawing step to form a.

[0011]

BEST MODE FOR CARRYING OUT THE INVENTION (Monolith Catalytic Converter) In a monolith catalytic converter of the present invention, a catalyst container holding a monolith catalyst inside is joined to a central axis of a main body portion holding the monolith catalyst inside and an exhaust gas pipe. It has a side end portion which is eccentric with the center axis of the joining end displaced.

The catalyst container has a tubular main body portion having both ends for holding the monolith catalyst therein and orthogonal to the axial direction, and is integrally formed with the main body portion at both ends of the main body portion and has an inner diameter from the end portion of the main body portion. Is shortened and the center axis of the joint end to be joined to the exhaust gas pipe and the center axis of the main body part are deviated from each other, and a funnel-shaped side end portion is formed. This catalyst container has a main body and a side end integrally formed, and does not have a joint such as a weld in the axial direction, the radial direction, and the circumferential direction. As a material used for this catalyst container, a molded stainless pipe is preferable.

The main body has a tubular shape whose both ends are orthogonal to the axial direction and holds the monolith catalyst therein. The main body has a tubular shape having an inner diameter that matches the outer circumference of the round bar-shaped monolith catalyst. The side end portion is formed in a funnel shape having an eccentricity with the center axis of the main body portion displaced from the center axis of the joint end where the inner diameter is shortened from the end portion of the main body portion. The central axis of the side end portion in a cross section perpendicular to the axial direction is displaced from the central axis of the main body portion. Further, the side end portion is formed so that the inner diameter is shorter than the end portion of the main body portion, and is formed so as not to coincide with the axial extension line of the main body portion.

The catalyst container is preferably formed by molding a tubular pipe material. This pipe material has a seamless joint, or even if it has a joint in the axial direction which is obtained by rolling a plate-shaped material into a cylinder and joining it, the joint part is a catalyst container like a commercially available one. Any material can be used as long as it does not impair the airtightness. As the monolith catalyst, one having both end faces formed in a round bar shape orthogonal to the axial direction is used. As this monolith catalyst, one used in a normal monolith catalytic converter is used. That is, a ceramic carrier is used as a carrier substrate, a ceramic catalyst supporting layer is formed on this 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 formed by winding a corrugated plate and a flat plate is held in an outer cylinder can be used as a carrier base material of the monolith catalyst.

The monolith catalyst is wrapped with a monolith seal material. This monolith seal material can be composed mainly of vermiculite having a thermal expansion property, a ceramic fiber having a high heat resistance and maintained in a sheet by a binder, or an alumina mat. This ensures a change in the gap between the catalyst container and the catalyst surface that occurs under cold conditions, holds and fixes the catalyst, and prevents leakage of exhaust gas.

The body portion preferably has a catalyst holding portion whose inner diameter is smaller than that of the body portion. This thinly formed end portion holds the outer peripheral surface of the monolith catalyst inserted inside the main body portion and prevents the monolith catalyst from being axially displaced and missing. (Manufacturing Method of Monolith Catalytic Converter) The manufacturing method of the monolith catalytic converter of the present invention includes an inserting step of inserting a monolith catalyst into a tubular pipe material, and a step of fixing the pipe material to a chuck portion of a drawing machine. And a spatula drawing process for forming an eccentric funnel-shaped outer end portion with the central axis of the main body portion displaced.

The inserting step is a step of inserting the round bar-shaped monolith catalyst into the cylindrical pipe material. The step of fixing to the chuck part is a step of fixing the pipe material in which the monolith catalyst is inserted to the chuck of the spatula processing machine. In the spatula drawing process, the rotation center of the chuck part and the processing roller are set so that the processing roller is slightly inside the outer circumference of the pipe material while giving relative rotation between the chuck part and the processing roller of the spatula drawing machine. Spatial processing is performed between the open end of the pipe material and the end of the main body with a constant radial distance between them, and the radial direction between the rotation center of the chuck section and the processing roller is sequentially set. The distance between the open end of the pipe material that has already been drawn while shortening the distance and the part that is slightly apart from the end of the main body is drawn, and the center axis of the main body shifts and the eccentric funnel-shaped outside This is a step of forming an end portion.

In this spatula drawing step, relative rotation is applied between the chuck portion for fixing the pipe material and the processing roller. Here, the relative rotation given between the chuck part and the processing roller is given by the rotation of the chuck part or the processing roller, so that the processing roller can come into contact with the entire circumference of the outer peripheral surface of the pipe material. Is given to. The center of rotation at this time preferably coincides with the central axis of the pipe material.

Further, the spatula drawing in the spatula drawing process is as follows.
When the processing roller moves between the open end of the pipe material and the end of the main body, the amount of pipe material squeezed in the radial direction is small. Be seen. The movement of the processing roller here means that the processing roller moves slightly inside the outer circumference of the pipe material.

The repetitive movement of the processing roller may be either unidirectional movement between the open end and the main body or reciprocal movement 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 of repeating the movement of the processing roller 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. It may be a repeating method or a movement in a reciprocating movement between the open end and the main body.

In the spatula drawing step in the manufacturing method of the present invention, the spatula drawing is performed by rotating the pipe material in an eccentric state so that the center of rotation of the chuck portion coincides with the central axis of the processing circle to be spatulated. It is preferably a step. That is, the chuck may be rotated in a state where the center of rotation of the chuck portion does not coincide with the center axis of the pipe material, and the spatula drawing process may be performed. In this case, if you apply normal spinning drawing,
The end of the main body is not perpendicular to the axial direction and the end is inclined so that a wasteful space is formed between the end and the end face of the monolith catalyst so that weight, cost and heat capacity are wasted. Become. Therefore, it is important to control the radial movement of the processing roller and the pipe material.

The spatula drawing step in the manufacturing method of the present invention is preferably carried out by a spinning drawing apparatus. The spinning drawing apparatus has the configuration shown in the schematic view of FIG. That is, this device is designed so that the chuck can hold the pipe material with the one end opening of the pipe material protruding horizontally, and this chuck is connected to the rotary shaft of the motor, whereby the pipe material is rotated. It can be rotated around. This chuck is
A hydraulic cylinder allows the pipe material to move in a vertical direction, which is a direction perpendicular to the axis of rotation. Further, above the one end opening of the pipe material, there is provided a vertically movable table which can be vertically moved in the vertical direction by a hydraulic cylinder, and the vertically movable table can be horizontally moved in the direction in which the rotary shaft extends by the hydraulic cylinder. A horizontal transfer table is provided. And
A processing roller is attached to the horizontal moving table by a bracket so that the processing roller can be driven. The processing roller has a U-shaped cross section.

In the manufacturing method using this apparatus, first, the pipe material having the monolith catalyst inserted therein is fixed to the chuck of the drawing machine. Then, by rotating the motor, the chuck and pipe material linked to this motor are rotated. After that, press the processing roller against the open end of the rotated pipe material and move the horizontal moving table toward the base end side in the horizontal direction as well as in the vertical direction, and move the chuck in the vertical direction by the hydraulic cylinder. The pipe material is drawn into an eccentric funnel shape. Here, since the amount of reduction that is processed by one movement of the processing roller is limited, the side edge is formed by repeating the movement of the processing roller.

[0024]

EXAMPLES The monolith catalytic converter of the present invention and the method for producing the same will be described below with reference to examples. (Embodiment 1) This embodiment is a monolith catalytic converter shown in FIGS. 1 and 2, in which a catalyst container 1 made of stainless steel, a monolith catalyst 3 held in the catalyst container 1,
It is composed of

The monolith catalyst 3 has a ceramics catalyst support layer formed on the surface of a ceramics support, and a catalyst metal is supported on the catalyst support layer, and has a diameter of 129 m.
m, and a rod-shaped member having an axial length of 150 mm is used. In addition, this monolith catalyst has a ring-shaped holding member (not shown) formed by accumulating stainless fibers having a thermal expansion coefficient larger than that of stainless steel used for the catalyst container on the peripheral surface on one end side, and a central peripheral surface on the peripheral surface. A monolith seal material (not shown) made of ceramic fiber and vermiculite is wound around. At this time, an alumina mat may be used as the monolith seal material.

The catalyst container 1 has a diameter of 140 mm and a thickness of 1.
A molded 5 mm stainless pipe is used. This catalyst container has a main body 11 having an axial length of 150 mm and an axial length of 86 at both ends of the main body 11.
An eccentric funnel-shaped side end portion 13 of mm is formed. This side end portion 13 has a gradually decreasing inner diameter so that the inner diameter at the joint end 15 side with the exhaust gas pipe becomes shorter so that the main body portion 11 of the catalyst container 1 and the exhaust gas pipe having a shorter diameter than the main body portion can be connected. The central axis of the pipe forming the main body 11 and the central axis of the joint end with the exhaust gas pipe are 35 mm.
Deviated. The joint ends 15 of the side end portions 13 open at symmetrical positions at both ends of the main body portion 11. That is, as shown in FIG. 2, the extension lines of the central axes of the two side end portions 13 formed at both ends of the main body portion 11 are formed so as not to overlap.

In the monolith catalytic converter of this embodiment, since the end 12 of the main body 11 holding the monolith catalyst 3 is orthogonal to the axial direction, no waste space is formed in the catalyst container 1, and the weight and heat capacity are small. Is getting smaller. Further, since the joint end 15 is not formed on the extension line of the central axis of the main body 11, it can be freely aligned with the pipe path. (Production of Monolith Catalytic Converter) The monolith catalytic converter is produced by inserting the monolith catalyst into a stainless steel pipe molded into a catalyst container and then drawing the pipe with a spinning drawing device.
Here, the spinning drawing apparatus has the structure shown in the schematic view of FIG. That is, the chuck 51 that rotates in conjunction with the motor 52, the hydraulic cylinder 53 that moves the chuck 51 in the vertical direction, the processing roller 61 that deforms the pipe 10 mounted on the chuck 51, and the processing roller 61 in the axial direction. It is composed of hydraulic cylinders 62, 62 that are moved in the radial direction.

That is, first, the monolith catalyst 3 preliminarily formed in the shape of a round bar having a diameter of 129 mm and an axial length of 140 mm in which the holding member and the monolith seal material are wound around the peripheral surface is molded into the catalyst container 1. Inner diameter is 137
The stainless steel pipe 10 having a thickness of 1.5 mm and a thickness of 1.5 mm was inserted. 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 device so that the central axis of the pipe 10 is held horizontally. The chuck 51 used for this fixing is connected to the rotating shaft of the motor 52, and the chuck 51 also rotates in conjunction with the rotation of the motor 52.

Next, with the stainless pipe 10 fixed to the chuck 51, the motor 52 is set to 700 rpm.
Rotate with. As the motor 52 rotates, the chuck 51 connected to the motor 52 rotates. In the rotating pipe 10, a processing roller 6 is attached to a tip end portion processed at a joint end 15 of the side end portion 13 with the exhaust gas pipe.
1 was pressed to perform spatula drawing to deform the pipe 10. Processing roller 6 pressed against pipe 10
1 moves from the open end of the pipe 10 toward the chuck 51, and also moves in the vertical direction away from the central axis of the pipe 10 by the hydraulic cylinder 53. Further, 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
Is drawn and processed. Here, the central axis of the pipe 10 and the rotation axis of the chuck 51 coincide with each other. 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 Figure 5.
It was shown to.

This drawing process was performed on the openings at both ends to obtain a monolith catalytic converter having side ends whose eccentricity was controlled at both ends. By using this manufacturing method, the monolith catalytic converter can be obtained by molding once, so that it is not necessary to change the stage or prepare a large number of molding machines, and it is possible to reduce the manufacturing time and cost. Further, in the method for manufacturing a monolith 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 deviated, the movement of the roller 61 and the processing roller 61 are controlled. Therefore, the eccentric side end can be processed.

Further, as another method for manufacturing a monolith catalytic converter, as shown in FIG. 7, the processing roller moves in the vertical and horizontal directions while rotating on the outer circumference of the pipe, and the chuck moves in the vertical direction. It is also possible to process the eccentric side end by performing a spatula drawing process.
Another embodiment of the monolith catalytic converter of the present invention will be described below.

(Embodiment 2) In this embodiment, as shown in FIG. 8, the end portion 12 of the main body is formed thin and
The monolith catalytic converter is the same as that of the first embodiment except that the main body portion 11 and the side end portion 13 are integrally formed. That is, the main body 11 of this embodiment has an axial length of 150.
The stainless steel pipe has a diameter of 140 mm, a diameter of 140 mm, and a thickness of 1.5 mm, and the end portion 12 of the main body portion is formed thin so that the inner diameter is 137 mm. In addition, the end 12 of the main body, which is thinly formed, holds and fixes the monolith catalyst 3 via the monolith seal material 31.

In the production of the monolith catalytic converter of the present embodiment, while rotating the stainless pipe holding the monolith catalyst therein, the processing roller of the drawing device was pressed in the central axis direction at the opening end of the stainless pipe. The pipe is moved in the vertical direction while being displaced in the vertical direction and the horizontal direction so as to form the side end portion and the end portion of the main body portion which is thinly formed.

In this embodiment, since the end portion of the main body portion is formed thinner than the main body portion, the monolith catalyst in the main body portion can be prevented from being displaced in the axial direction of the main body portion. It is possible to prevent slipping and loss.

[0035]

In the monolith catalytic converter of the present invention, since the central axes of the joining ends of the monolith catalyst and the exhaust gas pipe are deviated and eccentric, the monolith catalytic converter can be joined to the curved portion of the exhaust gas pipe. When this happens, the curvature of this curve can be loosened. In addition, the exhaust system as a whole can avoid interference with the body and height restrictions above the ground.
That is, the monolith catalytic converter of the present invention has an effect of reducing the space for joining with the exhaust gas pipe and increasing the degree of freedom in design.

[Brief description of drawings]

FIG. 1 is a perspective view of a monolith catalytic converter according to a first embodiment.

FIG. 2 is a cross-sectional view of the monolith 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 of inserting a monolith catalyst into a stainless pipe.

FIG. 5 is a drawing of drawing processing by a spinning drawing apparatus.

FIG. 6 is a drawing of drawing when the rotation axis of the pipe is deviated.

FIG. 7 is a drawing of drawing when the processing roller rotates on the outer circumference of the pipe.

FIG. 8 is a cross-sectional view of a monolith catalytic converter according to a second embodiment.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Catalyst container 10 ... Pipe 11 ... Main body 12 ... End of main body 13 ... Side end 3 ... Monolith catalyst 31 ... Monolith seal material 51 ... Chuck 52 ... Motor 53 ...
Hydraulic cylinder 61 ... Roller 62 ... Hydraulic cylinder

Claims (4)

[Claims] 1. A monolith catalytic converter comprising a catalyst container connected to an exhaust gas pipe, and a rod-shaped monolith catalyst having both end faces held in the catalyst container orthogonal to the axial direction, wherein the catalyst container comprises: Both ends of the monolith catalyst that hold the inside thereof are tubular main bodies that are orthogonal to the axial direction, and both ends of the main body are integrally formed with the main body, and the inner diameter of the main body is shortened from the ends. A monolith catalytic converter comprising: a funnel-shaped side end portion in which a central axis of a joining end joined to the exhaust gas pipe and a central axis of the main body part are deviated from each other. 2. The monolith catalytic converter according to claim 1, wherein the main body portion has a catalyst holding portion in which an inner diameter of the end portion is smaller than an inner diameter of the main body portion. 3. A rod-shaped monolith catalyst, a cylindrical main body having both ends for holding the monolith catalyst inside and a tubular main body orthogonal to the axial direction, and integrally formed with the main body at both ends of the main body. It is composed of a central axis of a joint end whose inner diameter is shortened from the end of the main body and which is joined to the exhaust gas pipe, and a catalyst container including a funnel-shaped side end eccentric with the central axis of the main body being displaced. A method of manufacturing a monolith catalytic converter, comprising: an inserting step of inserting a monolith catalyst into a tubular pipe material; a step of fixing the pipe material having the monolith catalyst to a chuck portion of a spatula drawing machine; Between the center of rotation of the chuck section and the processing roller so that the processing roller is slightly inward of the outer circumference of the pipe material while providing relative rotation between the section and the processing roller of the spatula drawing machine. In Spatial drawing is performed between the open end of the pipe material and the end of the main body with a constant radial distance, and the radial direction between the center of rotation of the chuck and the processing roller is sequentially set. The funnel is drawn while shortening the distance between the open end of the pipe material that has already been drawn and a portion slightly separated from the end of the main body, and the center axis of the main body is decentered A monolithic catalytic converter manufacturing method, comprising: a spatula drawing step of forming a circular outer end. 4. The step of drawing a spatula by rotating the pipe material in an eccentric state so that a center of rotation of the chuck portion coincides with a central axis of a processing circle to be drawn. 4. The method for manufacturing a monolith catalytic converter according to claim 3.