JP2000317533A - Catalyst converter container, and its manufacture - Google Patents

Abstract

PROBLEM TO BE SOLVED: To form a cone part on both sides of a body part to store a catalyst by spinning an end portion of a work of ellipsoidal or race-track shaped section in place of a conventional method for forming a catalyst converter container by joining upper and lower pressed containers with each other. SOLUTION: A roller is relatively rotated to a work 10 and its radius of rotation is gradually reduced while holding the work 10 by a holding device 20 with at least one end of the tubular work 10 of race-track shaped or ellipsoidal section in the direction orthogonal to the axis in an open condition. The holding device 20 has a jig 24 to support a range not abutted on the roller at the work 10, and a support surface of the ellipsoidal or race-track shaped section in the direction orthogonal to the axis is formed on an inner surface of the jig 24.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a catalytic converter container installed in an exhaust system of an automobile or the like and used for purifying exhaust gas, and a method of manufacturing the same.

[0002]

2. Description of the Related Art Conventionally, various types of catalytic converter containers have been known, and one of them has a shell shape as a whole as shown in FIG. As a cross section of the “shell shape”, as shown in FIG. 19, a race track shape 224 composed of a pair of separated semicircles and two straight lines connecting the two,
As shown in FIG. 20, there is an elliptical shape 226 bulging in the lateral direction. In any case, since the shell-shaped catalytic converter container has a small dimension in the height (thickness) direction and can be arranged using a narrow and flat space of the exhaust system in the automobile,
Widely used.

[0003] The shell-shaped catalytic converter container is
It was manufactured by pressing. In other words, a press die is pressed against the central portion of the plate-shaped material (work) while the peripheral portion of the work is held by the holding device to change the entire work into a container shape, and the upper container 212 and the lower container 214 shown in FIG. create. After that, the catalyst is stored in the space formed by the upper and lower containers 212 and 214, and the two containers 212 and 214 are welded or the like.
214 are joined by flange portions 216 and 218 on the periphery.
Thus, the catalytic converter container 210 having the main body 220 containing the catalyst and the cones 222 on both sides connected to the exhaust pipe is completed.

[0004]

However, the method for producing a shell-shaped catalytic converter container by the above-mentioned press working and the converter container produced by the method have the following problems. First, since the press working involves cutting the work into a predetermined shape and then deforming the work to form the catalytic converter container, the yield of the work is low due to its properties, and the manufacturing cost of the catalytic converter container 210 increases accordingly. I do. Second, the degree of freedom of the shape of the catalytic converter container is low. In other words, although the size of the main body 220 of the catalytic converter container is substantially the same, the minimum diameter of the cone part 222, that is, the diameter of the pipe, has various dimensions depending on the vehicle type. Only different types of catalytic converter vessels can be manufactured. In addition, if a plurality of types of press dies are prepared for the catalytic converter containers that differ only in the minimum diameter of the cone portion 222, the production efficiency is low. Third,
The heat capacity is increased by the flange portions 216 and 218,
The rise time to the catalyst activation temperature at the time of cold start of the vehicle is delayed, and the exhaust gas purification performance is inferior. Fourth, the size of the main body 220 is reduced by the amount that the flanges 216 and 218 formed for joining the upper container 212 and the lower container 214 protrude outward from the container, or the catalyst in the automobile is reduced. The converter space must be increased.

On the other hand, attempts have been made to form the catalytic converter container by spinning, and when the work has a cylindrical shape, a catalytic converter container having substantially desired dimensional accuracy can be manufactured. However, when the cross-sectional shape of the work is an elliptical shape or a race track shape, a portion of the cone near the main body is irregularly deformed, and a container having a desired dimensional accuracy cannot be obtained. This is mainly due to the difference between the cross-sectional shape of the work (ellipse, race track shape) and the orbit of the roller (circle).

The present invention has been made in view of the above circumstances, and an object thereof is to solve the problem by following the method of manufacturing a catalytic converter container by spinning. Therefore, first, the present invention has an object to provide a catalytic converter container having an elliptical cross section or a race track shape, which has no flange and joint surface on its surface, and has high reliability and easy quality control. . The present invention secondly provides:
Even if the cross-sectional shape of the work is elliptical or race track, the yield of the work is good, the manufacturing cost can be reduced, the degree of freedom of the shape is high, and cones of a predetermined shape can be formed at both ends of the main body by spinning. An object of the present invention is to provide a method for manufacturing a catalytic converter.

[0007]

In order to achieve the above object, a catalytic converter container according to the present invention has a cylindrical main body having an elliptical or race-track cross section in a direction perpendicular to an axis and containing a catalyst therein. And a cone portion integrally extending from both ends in the axial direction of the main body portion and having a cross section in the direction perpendicular to the axis having an elliptical or racetrack shape and having a diameter gradually reduced from the main body portion. In this catalytic converter container, by spinning both ends in the axial direction of a tubular work, a central portion of the work is used as a main body portion, and the spinned both ends of the work are used as a pair of the cone portions. is there.

In the method for manufacturing a catalytic converter container according to the present invention, at least one end of a tubular work having an elliptical or race-track-shaped cross section in a direction perpendicular to the axis is opened by utilizing spinning. While holding the work by the holding device, the roller is relatively rotated with respect to the work while being in contact with the one end of the work from the outer peripheral side, and the rotation radius is gradually reduced. As described above, when spinning a tubular work having an elliptical or race track shape in cross section, there is a problem that a portion of the cone portion near the main body portion is irregularly deformed. Therefore, in the present invention, a jig protruding in the axial direction from the holding device that holds the intermediate portion of the work toward the end portion is provided. This jig supports a portion of the end portion that is not in contact with the roller at a portion close to the main body, and has a support surface formed on an inner surface thereof. Here, the range of the workpiece that does not come into contact with the roller is a portion where the contour of the ellipse or the race track shape protrudes from the rotation locus of the roller, and the support surface of the jig has an elliptical or cross-sectional shape in the direction perpendicular to the axis. It has the shape of a race track.

A specific embodiment of the jig will be described. The jig is provided on each of the pair of upper and lower chucks, and has a main body and a protrusion protruding in the axial direction from the main body. The main body is a part that holds the work, and is attached to the chuck. The protruding portion is a portion that prevents irregular deformation of the work during drawing, and faces a portion of the work that is not drawn. For example, the protruding portion may have a generally triangular planar shape, and a cross-sectional shape having a triangular shape in which the thickness gradually decreases from the main body portion toward the distal end. Further, the outer surface of the projecting portion is constituted by a part of a conical surface determined by the relationship between the initial outer surface shape of the workpiece and the outer surface shape of the predetermined cone portion, that is, the advance amount and the axial movement amount of the revolving roller. .
The amount of protrusion of the protrusion substantially corresponds to a point at which a part of the elliptical or race track shape on the end of the work is left, that is, a point at which the revolution radius of the roller is smaller than the shortest diameter of the work.

During the spinning of the end of the work by the roller, the roller is moved in the axial direction from near the boundary between the end of the work and the main body toward the tip of the end while adjusting the amount of advance of the roller. This spinning is generally performed in two stages. In the first stage of the drawing, a portion of the contour of the workpiece whose diameter is larger than the revolving radius of the roller, that is, a portion of the elliptical or race track-shaped workpiece facing in the left-right direction is moved toward the center of the workpiece by the roller. More squeezed. There is no jig protrusion in this part,
Such a deformation of the work is possible. On the other hand, the part of the contour of the work whose diameter is smaller than the revolving radius of the roller and does not contact the roller is restricted by the support surface of the jig, and cannot be deformed away from the center. Slightly deforms toward the tip of the work. In this way, the portion of the workpiece facing in the vertical direction is formed of an elliptical or part of the shape of the race track, and the portion of the workpiece facing in the horizontal direction is formed of the first ellipse or an arc having a radius smaller than the diameter of the race track. Is formed.

In the second stage of the drawing, the orbital radius of the roller is considerably smaller than at the beginning, and its rotation locus is smaller than the minimum diameter of the work. Therefore, both the part facing the work in the vertical direction and the part facing the work in the horizontal direction are narrowed by the rollers. However, the portion of the workpiece facing in the left-right direction has a larger amount of drawing than the portion facing in the vertical direction, and a part of the portion resistant to k in the left-right direction is deformed toward the portion facing the vertical direction. Thus, a second conical portion having a circular cross section and a conical shape is formed.

In the manufacturing method of the present invention, when a cone is formed at the end of the work, a mandrel is inserted into the hollow portion of the work as necessary, so that the work is irregularly inward in the radial direction. Deformation can be prevented. In addition, since the work and the roller only need to rotate relative to each other, the roller may be moved in the axial direction without rotating while rotating the work, or the work may be kept stationary while rotating in the axial direction while rotating the roller. You may move it.

[0013]

Embodiments of the present invention will be described below with reference to the accompanying drawings. <First Embodiment> First, a method of manufacturing a catalytic converter container from a work having a racetrack cross-section by spinning will be described. As shown in FIG.
A holding device 2 capable of opening and closing a longitudinal middle portion 12 of a metal-made tubular work 10 having a racetrack cross section in a vertical direction.
Hold by 0. The work 10 is obtained by bending a rectangular plate material into a circular shape and joining its end circles by plasma welding or the like, and contains a catalyst (not shown) in advance. The holding device 20 includes a pair of chucks 22 that open and close in a vertical direction, and a pair of jigs 24 attached to opposing surfaces of the chucks 22. The upper and lower chucks 22 and the jig 24 have the same shape.

As shown in FIGS. 2 and 3, the upper and lower chucks 22 each have a semicircular jig mounting surface 26, and a work support surface 25 on the front side has a shape obtained by bisecting a race track shape. A jig 24 having a crescent-shaped cross section having a semi-circular mounting surface 27 is mounted, and both ends of the jig 24 protrude from the chuck 22 in the axial direction. Projections 28 project in the axial direction from both ends of the jig.
Is a triangular shape when viewed from above, and its thickness is thicker at the root and gradually thinner toward the tip, and the upper surface 29 is formed from a part of a conical surface.

In this state, the work 1 protruding from the jig 24 is rotated while rotating the holding device 20 to rotate the work 10.
The roller 30 is moved closer to the end 14 of the work 10 from a direction perpendicular to the longitudinal direction of the work 10 and is advanced toward the front end to perform drawing. The amount of advance of the roller 30 increases as the roller advances toward the tip of the work 10.
In the first half of the drawing process, a portion of the end portion 14 of the workpiece 10 which is close to the intermediate portion 12 in the axial direction and which is in contact with the roller 30 in the circumferential direction (the arc portion 14a facing in the left-right direction) is It is drawn to a smaller radius. However, the roller 3 of the work 10
0 does not contact (the straight line portion 14 facing in the vertical direction)
In b), since it is restricted by the support surface 25 of the protruding portion 28, it cannot be deformed in the vertical direction, and is maintained in the original race track shape.

The conical surface 29 formed on the projecting portion 28 of the jig 24 can avoid interference between the roller 30 and the jig 24 when the roller 30 is moved in the radial and axial directions. Here, if the jig 24 is not provided, as shown in FIG.
, The straight line portion 1 as shown by the two-dot chain line
4b tends to deform into a cylindrical shape, and the predetermined race track shape is damaged.

On the other hand, in the latter half of drawing, FIG.
As shown in FIG.
The distance between “a” is considerably smaller than at the beginning, but is still larger than the revolution radius of the roller 30. On the other hand, the distance between the upper and lower linear portions 14b of the work 30 is
Smaller than the orbital radius of. The roller 30 is connected to the jig 24
At a position deviated in the axial direction from the protruding portion 28. Therefore,
The arc portion 14a is squeezed by the roller 30, and FIG.
As shown in (1), the excess portion moves to the straight portion 14b (14c), and the end of the work is drawn into a conical shape.

In this manner, as shown in FIG. 6, the catalyst can be housed therein, and a cylindrical main body 42 having a racetrack-shaped cross section in the direction perpendicular to the axis, and a shaft extending integrally from both ends thereof. A catalytic converter container 4 comprising a pair of cone portions 44 whose cross-sectional shape in the perpendicular direction is a racetrack shape and whose diameter is gradually reduced, and a cylindrical pipe 46 at the end thereof.
No. 0 was formed by spinning both ends 14 of the tubular workpiece 10 in the direction perpendicular to the axis in a racetrack shape with the roller 30. Work 1
In order to form a cone at the other end 14 of the workpiece 0, the holding device 20 is opened up and down, the work 10 is turned left and right, the holding device 20 is closed, and the same spinning process as described above is performed at this other end. What is necessary is just to give to the part 14.

As an effect peculiar to this embodiment, since the cross-sectional shape of the catalytic converter container 40 is a race track shape, the catalytic converter container 40 can be arranged in a narrow space in the vertical direction. In addition, since the back surface 27 of the jig 24 and the jig mounting surface 26 of the chuck 22 are formed in a semi-cylindrical shape, not only can the back surface 27 and the mounting surface 26 be easily processed, but also fine positioning after the processing becomes unnecessary. So chuck 2 of jig 24
2 can be easily attached and detached.

<Comparative Example> Here, a comparative example will be described with reference to FIG. This comparative example differs from the above-described embodiment in that no protrusion is formed at the tip of the jig 50.
That is, the jig 50 attached to the holding device 20 has a semicircular outer surface, and has an inner surface bisected from the racetrack shape. However, in this case, when spinning a portion close to the inner intermediate portion 12 of the end portion 14 of the work 10 having a race track shape in cross section, a portion protruding from the locus of movement (rotation) of the roller moves toward a range where the roller does not contact. It is difficult to obtain a cone having a desired shape due to deformation.

<Second Embodiment> Next, referring to FIG.
An embodiment in which cone portions are formed on both ends 72 of a work 70 having an elliptical cross section by spinning will be described. The procedure is as follows:
This is substantially the same as the case where the cone portions 44 are formed at both ends 14 of the “0” (see FIGS. 1 to 6), and a projecting portion 62 is formed at the tip of the jig 60. However, the difference is that the support surface 64 on the inner surface of the jig 60 has a shape obtained by bisecting an ellipse. As an effect peculiar to this embodiment, since the cross section of the work 70 is elliptical, it is relatively close to the locus of movement of the roller, and no excessive force is applied to the work 70 when spinning the end 74 of the work 70. Points.

<Third Embodiment> In this embodiment,
In the first embodiment, an improvement is made to more reliably prevent inward deformation of the end portion when forming a cone portion by spinning at the end portion of the work having a racetrack cross section. . That is, FIGS. 3, 4 and 7
As described above, by providing the jig 24 on the holding device 20, it is possible to prevent the end portion 14 of the work 10 from being deformed radially outward during drawing.
On the other hand, as shown in FIG. 10, the work 10 restrained from deforming outward by the jig 24 tends to deform inward.

In order to prevent such deformation of the work,
In this embodiment, a mandrel is inserted into the hollow portion of the work during drawing. Hereinafter, it will be described in detail with reference to FIGS. A work 80 having a race track cross section shown in FIG. 11 is held by a holding device 90 shown in FIG. The holding device 90 is the holding device 20 (see FIG. 1).
It has a pair of holding members 92 and a pair of jigs 94 attached to the opposing surfaces thereof, and a protrusion 96 is formed at the tip of the jig 94.

In the case where cones are formed at both ends 82 of the work 80 by the holding device 90, as shown in FIG. Mandrel 8 in hollow part
Insert 6. This mandrel 86 is composed of a plurality of members 86a as shown in FIG. 16 (a), and has a racetrack cross section smaller than the cross section of the work 80 over its entire length or a shape similar thereto, and is apparent from FIG. In this way, the tip extends to near the end face of the holding member 92. In this state, the rotating roller 30 is moved to the work 80.
The end portion 82 of the work 80 is drawn into a cone shape by controlling the amount of advance of the roller 30 in the radial direction and the amount of movement in the axial direction by moving the roller 80 toward the center thereof and making contact with the end portion 82. In the first half of the drawing, the outer surface of the end portion 82 of the work 80 is fixed to the jig 92 in the same manner as in the first embodiment.
The protrusion 94 restricts outward deformation. Also,
Since the mandrel 86 is located close to the inner surface of the end portion 82 and there is no large gap between the work 80 and the mandrel 86, the end portion 82 (particularly, the straight portion) of the work 80 is irregularly inward. Is prevented from being deformed.

Since the inner diameter of the end portion 82 of the work 80 decreases as the drawing process proceeds, as shown in FIG. 16 (b), by extracting a part of the plurality of members 86a stacked in the left-right direction, The size of the mandrel 86 in the left-right direction is reduced. In this way, the mandrel 86 does not hinder the drawing of the end 82 of the work 80. The mandrel 86 is removed from the work 80 immediately before the pipe portion 85 is formed at the tip of the cone portion 84.
Thus, as shown in FIG. 14, the cone portion 84 and the pipe portion 85 are formed at the end portion 82 of the work 80 by spinning.

Instead of the mandrel 86 shown in FIG. 16A, as shown in FIG. 17A, a rod 88b having a cone 88a at the tip and a case 88c for accommodating the rod 88b are provided. May be inserted from the free end into the hollow portion. Also in this case, as drawing of the end portion 82 of the work 80 progresses, the mandrel 88 is replaced with a smaller one of the cone portions 88a as shown in FIG. 17B.

[0027]

As described above, according to the catalytic converter container of the present invention, since the cone portion is formed by spinning a tubular work, the pressed half-container is joined by welding. No welding work is required. As a result, it is not necessary to pay attention to the quality of the welding, the reliability of the catalytic converter container is improved, and the quality control is facilitated. Further, since there is no flange portion around the main body of the catalytic converter container, the space for accommodating the catalyst inside the catalytic converter container increases by that much, the heat capacity of the catalytic converter container decreases, and the action of purifying exhaust gas improves. . Further, according to the manufacturing method of the present invention, since the cone portion is formed by spinning the both ends of the tubular work, there is no problem of a decrease in the yield peculiar to the press working, and almost all of the work is catalyzed. Can be used for converter containers. Further, since the cone portion of the catalytic converter container is formed by spinning, the shape of the cone portion and the dimension of the minimum diameter thereof can be adjusted only by adjusting the amount of advance of the roller, thereby increasing production efficiency.

[Brief description of the drawings]

FIG. 1 is a perspective view (before processing) showing a first embodiment of the present invention.

FIG. 2 is a front view of the first embodiment.

FIG. 3 is a side view of the first embodiment.

4A and 4B are explanatory diagrams of the operation of the first embodiment, in which FIG. 4A shows a state before drawing and FIG. 4B shows a state after drawing.

FIG. 5 is a perspective view (after processing) showing the first embodiment.

FIG. 6 is a perspective view of a catalytic converter container manufactured according to the first embodiment.

FIG. 7 is an explanatory diagram for explaining an operation of the first embodiment.

FIG. 8 is a perspective view showing a comparative example.

FIG. 9 is a perspective view showing a second embodiment of the present invention.

FIG. 10 is an explanatory diagram for explaining a room for improvement of the first embodiment.

FIG. 11 is a perspective view of a work used in a third embodiment of the present invention.

FIG. 12 is a perspective view (before processing) illustrating an operation in the third embodiment.

FIG. 13 is a perspective view (during processing) illustrating an operation in the third embodiment.

FIG. 14 is a perspective view (at the end of processing) for explaining the operation in the third embodiment.

FIG. 15 is a cross-sectional view illustrating an operation in the third embodiment.

FIGS. 16 (a) and (b) are perspective views of a mandrel used in the third embodiment.

17A and 17B are perspective views of another mandrel used in the third embodiment.

FIG. 18 is a perspective view showing an example of a conventional catalytic converter container.

FIG. 19 is an explanatory view showing a race track shape in cross section of a work.

FIG. 20 is an explanatory diagram showing a cross-sectional elliptical shape of a work.

[Description of Signs] 10, 70, 80: Work 12: Intermediate part of work 14, 74, 82: End of work 20, 90: Holding device 22, 92: Chuck 24, 60, 9
0: Jig 25: Support surface 28, 94: Projection 30: Roller 40: Catalytic converter container 42: Main body of container 44: Cone of container

 ──────────────────────────────────────────────────続 き Continued on the front page (72) Inventor Tetsu Takahashi 1 Toyota Town, Toyota City, Aichi Prefecture Inside Toyota Automobile Co., Ltd.

Claims (4)

[Claims] 1. A cylindrical main body for accommodating a catalyst therein having an elliptical or race-track cross-section in a direction perpendicular to the axis, and a cross-section in a direction perpendicular to the axis extending integrally from both ends in the axial direction of the body. The central part of the tubular workpiece is formed into a main body by spinning both ends in the axial direction of the tubular workpiece, the cone being formed in an elliptical or race track shape and having a gradually reduced diameter from the main body. A catalytic converter container comprising a pair of cones formed at both ends of a workpiece by spinning. 2. A tubular work having an elliptical or race-track cross-section in a direction perpendicular to the axis, wherein at least one end of the tubular work is held open by a holding device, and the end of the work is connected with the one end of the work from an outer peripheral side. In a method for manufacturing a catalytic converter container, in which a roller is relatively rotated with respect to a work in a contact state and a rotation radius is gradually reduced, the holding device supports a portion of the work that does not contact the roller. A method for manufacturing a catalytic converter container, comprising: a jig; and a support surface having an elliptical or race-track cross section in a direction perpendicular to the axis formed on an inner surface of the jig. 3. The method according to claim 2, wherein said jig projects axially from a side surface of said holding device. 4. The method according to claim 2, wherein the rotational radius of the roller is gradually reduced while a mandrel is inserted into the hollow portion of the work.