JP2001286955A - Method and apparatus for forming tube - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a forming method and an apparatus therefor to reduce an end part of a tube of oval cross section without causing deformation except a reducing part. SOLUTION: A converter main body 11 (tube) of oval cross section is held with a chuck 32 (holding means) of a spinning apparatus M (forming apparatus). A roll 80 is positioned on the outer periphery of the converter main body 11. The roll 80 is rotated around the axial line of the converter main body 11 by a motor 62 (rotating means), in synchronizing with the rotation, is reciprocated in the diametrical direction of the converter main body 11 by a servo motor 71 (reciprocating means) and is continuously pressed to the converter main body 11. Further, the roll 80 is moved in the direction of the axial line L1 by a servo motor 51 (moving means).

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method and an apparatus for reducing the diameter of a tube having an elliptical cross section.

[0002]

2. Description of the Related Art For example, as a main body of a catalytic converter or a silencer of an internal combustion engine, a tube having an elliptical cross section is often used in consideration of a mounting space in a vehicle. This main body tube has a larger diameter than the exhaust pipe having a perfect circular cross section, as well as a major diameter, as well as a short diameter. The end of the main body pipe has a perfect circular cross section toward the tip. As described above, and is connected to the exhaust pipe. In order to manufacture a main body tube having such a shape, a pair of molded products having a shape obtained by dividing the tube into two along one diameter by a press is first produced, and then these molded products are welded and integrated. Is adopted.

[0003]

However, the conventional manufacturing method described above is inefficient because it requires two different operations, ie, pressing and welding. Therefore, there has been a request to be able to manufacture by spinning processing in which the diameter is reduced by relatively rotating the tube while pressing the roll against the tube. However, the conventional spinning device corresponds to a pipe having a perfect circular cross section, and the roll rotates around the axis of the pipe so as to draw a perfect circular locus. When this device is applied to a tube with an elliptical cross section, at the beginning of processing, the roll is applied only to the longer diameter portion of the tube end and the diameter is reduced, and the shorter diameter portion is reduced until the longer diameter portion becomes equal to the shorter diameter. Not processed. At this time, due to the effect of the diameter reduction of the long diameter side portion, the short diameter side portion is expanded and deformed. This deformation is transmitted not only to the end of the tube to be processed but also to the other tube portion where the original elliptical shape should be maintained, resulting in a problem that the product shape is distorted. The present invention
The purpose of the present invention is to provide a method and an apparatus that do not deform a pipe portion other than a pipe end when spinning an end of a pipe having an elliptical cross section. Is to provide.

[0004]

According to a first aspect of the present invention, there is provided a method for reducing the diameter of an end of a tube having an elliptical cross section, wherein a roll is relatively rotated around the tube. Along with moving the tube in the axial direction of the tube,
By pressing against the pipe, the longer diameter of the pipe end is reduced toward the tip, and the shorter diameter of the pipe end is reduced at a rate smaller than the longer diameter, so that the cross section of the pipe tip is substantially a perfect circle. It is characterized by the following.

A second invention is a method of reducing the diameter of an end of a tube having an elliptical cross section. The outer periphery of the tube is pressed by rotating a roll against the tube while rotating relatively around the tube. A first step of forming an annular groove in the first step, and thereafter, the same or another roll as in the first step is relatively rotated around the pipe, and while relatively moving in the axial direction of the pipe, And a second step of reducing the diameter by pressing the annular groove toward the distal end side.

A third aspect of the present invention is an apparatus for reducing the diameter of an end of a tube having an elliptical cross section, comprising: a gripper for gripping the tube;
A roll disposed on the outer periphery of the pipe, a rotating means for relatively rotating the roll about an axis of the pipe, and reciprocating the roll in a radial direction of the pipe in synchronization with the rotating means; And reciprocating means for continuously pressing the reciprocating member.

According to a fourth aspect of the present invention, there is provided an apparatus for reducing the diameter of an end of a tube having an elliptical cross-section, comprising: a roll; first rotating means for rotating the roll about an orbital axis remote from the roll; Gripping means for eccentrically gripping the orbital axis from the revolving shaft,
Second rotating means for rotating the gripping means around the axis of the pipe; and in synchronization with the second rotating means, the gripping means is reciprocated relative to the revolving axis in a direction orthogonal to the revolving axis. Reciprocating means for moving the pipe, whereby the pipe is positioned so as to follow the rotation trajectory of the roll, and is pressed against the roll.

A fifth invention is characterized in that, in the third or fourth invention, a moving means for relatively moving the roll in the axial direction of the tube is further provided.

[0009]

Embodiments of the present invention will be described below with reference to the drawings. 1 to 7 show a first embodiment of the present invention. In this embodiment, a catalytic converter 10 of an internal combustion engine is connected to a spinning device M (forming device).
The spinning process is used.

First, the catalytic converter 10 will be described. As shown in FIG. 5 and FIG.
Includes a converter main body 11 made of a steel tube or the like, and a catalyst carrier 12 housed in the converter main body 11. The converter main body 11 includes a base tube 11a having a uniform elliptical cross section (see FIG. 2), and a base tube 11a.
And a tapered portion 11b (tube end) extending from the end portion.
The tapered portion 11b is formed by spinning using the spinning device M. The cross section of the tapered portion 11b decreases in diameter toward the distal end and approaches a perfect circle. As shown by the phantom line in FIG. 7, an exhaust pipe 19 having a perfect circular cross section is
Will be connected.

As shown in FIG. 2 and FIG.
Is a lattice structure in which a catalyst is supported on a honeycomb structure, and the outer periphery of the honeycomb structure is formed in an elliptical shape and is housed in the raw tube portion 11a. The outer periphery of the catalyst carrier 12 and the tube portion 11
A holding mat 13 (holding material) made of a ceramic fiber or the like is interposed between the inner circumference of “a” and “a”.

The spinning device M will be described. FIG.
As shown in the figure, the device M comprises a base 20 and this base 2
0 includes a tube support unit 30 disposed on the right side and a roll support unit 40 disposed on the left side. The tube support unit 30 includes a support 31 erected on the base 20.
And a chuck 32 fixed to the upper end of the column 31
(Gripping means). The catalytic converter 10 before spinning is attached to the chuck 32 by the axis L1.
Is held right and left. As shown in FIGS. 1 and 2, the converter body 11 before processing has a uniform elliptical cross section over its entire length, and has a catalyst carrier 12 therein.
And the holding mat 13 are stored in advance.

The roll support unit 40 includes a slide mechanism 50 provided on the base 20 and the slide mechanism 50.
The revolving mechanism 60 provided above, the three reciprocating mechanisms 70 provided on the revolving mechanism 60,
0, and three rolls 80 provided at the same position.

The slide mechanism 50 has a servomotor 51 (moving means) fixed to the base 20 and a slider 52 slidably mounted on the base 20. A lead screw 53 is connected to the servomotor 51, and a guide nut 54 is connected to the lead screw 53.
Is screwed. The guide nut 54 serves as the slider 5
It is fixed to 2. Thereby, the servo motor 51
As a result, the lead screw 53 is rotated, the guide nut 54 and the slider 52 are slid left and right, and the roll 80 is moved left and right.

A support column 41 is provided upright on the slider 52, and the revolving mechanism 60 is provided at an upper end of the support column 41. The revolving mechanism 60 has a hollow disk-shaped roll holder 61 rotatably supported by the support column 41, and a motor 62 (rotating means) connected to the roll holder 61. The axis L2 of the roll holder 61 is arranged so as to coincide with the axis L1 of the catalytic converter 10 held by the chuck 32. The motor 62 causes the roll holder 61 to rotate at high speed around the axis L2, and thus the roll 80 rotates (revolves) at high speed around the axis L2.

The three reciprocating mechanisms 70 include the roll holder 6
1 are arranged 120 degrees apart in the circumferential direction. Each reciprocating mechanism 70 is connected to a servo motor 71 (reciprocating means) provided on the outer peripheral surface of the roll holder 61 and is accommodated in the roll holder 61 in a radial direction. Lead screw 72
And a guide nut 73 screwed to the lead screw 72, and a shaft 74 provided to the guide nut 73. The shaft 74 is attached to the roll holder 6.
It projects toward the tube support unit 30 via a guide slit 61a formed in the right side plate 1. The roll 80 is provided at the tip of the shaft 74. As a result, the lead screw 72 is rotated by the servomotor 71, and the guide nut 73 and thus the roll 80 are reciprocated in the radial direction of the roll holder 61. Note that the roll 80 can rotate (rotate) around the axis of the shaft 74.

The spinning apparatus M configured as described above
A method for spinning the catalytic converter 10 will be described. The spinning process includes, as shown in FIGS. 1 to 3, a first step of forming a tubular groove 11 c at a boundary between the processing target portion 11 b ′ (tube end portion) and the raw tube portion 11 a to be a tapered portion 11 b; Thereafter, as shown in FIG. 4, a second step of tapering the processing target portion 11b 'on the tip side from the tubular groove 11c is performed.

The first step will be described. First, as shown in FIGS. 1 and 2, the roll 80 is positioned by the slide mechanism 50 radially outward of the boundary of the processing target portion 11 b ′. Then, the roll 80 is rotated around the axis L2 by the revolving mechanism 60. In synchronization with this rotation, the roll 80 is reciprocated in the radial direction by the reciprocating mechanism 70 so as to be continuously pressed against the converter main body 11. That is, the converter body 11 is attached to the roll 80.
To draw an elliptical rotation trajectory along. Thereby, as shown in FIG. 3, an annular groove 11c is formed in converter main body 11. This annular groove 11c is located on the tip side (left side) of the catalyst carrier 12.

Subsequently, the second step is performed. In this step, the roll 80 is slid in the left-right direction by the slide mechanism 50 in addition to the synchronous operation of the revolving mechanism 60 and the reciprocating mechanism 70. First, the right end of the range of the sliding operation is set to the annular groove 11c, and the left end is set to the leading edge (left edge) of the converter main body 11. Then, the right end of the range of the sliding operation is gradually shifted to the front end side of the processing target portion 11b '. As a result, as shown in FIG. 4, the processing target portion 11b 'on the tip side from the annular groove 11c is tapered.

Moreover, the roll 80 is pressed relatively strongly by the reciprocating mechanism 70 when the roll 80 faces the long diameter side of the converter body 11, and is pressed relatively weakly when the roll 80 faces the short diameter side. To do. Thereby, the diameter reduction ratio on the minor diameter side is smaller than that on the major diameter side. As a result, FIG.
As shown in Fig. 7, the cross section of the processing target portion 11b 'approaches a perfect circle as it goes toward the tip, and becomes a perfect circle at the tip edge. Thus, the tapered portion 11b is formed. As shown in FIG. 7, the annular groove 11c becomes a step 11c '. The step 11 c ′ projects radially inward from the outer peripheral edge of the catalyst carrier 12.

In the second step, the processing target portion 11
Not only the major-diameter portion but also the minor-diameter portion of b ′ is reduced in diameter at a smaller rate than the major-diameter portion, and the cross section gradually approaches a perfect circle, so that it is possible to prevent the raw tube portion 11a from being deformed. it can. In addition, the stress applied from the roll 80 to the processing target portion 11b 'can be blocked by the annular groove 11c (or the step 11c') and can be prevented from being transmitted to the raw tube portion 11a, so that the deformation of the raw tube portion 11a can be further ensured. Can be prevented. Consequently, it is possible to prevent the catalyst carrier 12 in the raw tube portion 11a from being damaged.

Thereafter, the converter body 11 is mounted on the chuck 32 with the left and right directions reversed, as shown in FIG.
In the same manner as above, a tapered portion 11b is also formed on the opposite end (right end) of converter main body 11. by this,
The catalytic converter 10 is completed, incorporated in an internal combustion engine, and mounted on a vehicle.

The catalytic converter 10 mounted on the vehicle
Has the following effects. That is, as shown in FIG. 7, since the step 11 c ′ projects radially inward from the holding mat 13, the exhaust gas sent from the exhaust pipe 19 is prevented from being strongly blown to the leading edge of the holding mat 13. It is possible to prevent the holding mat 13 from being eroded and the fibers constituting the holding mat 13 from being scattered. Further, since the step 11c 'projects radially inward from the catalyst carrier 12, the catalyst carrier 12 can be prevented from being displaced in the direction of the axis L1 due to vibration of the vehicle or the like.

Next, another embodiment of the present invention will be described.
In the following embodiments, the same components as those in the first embodiment are denoted by the same reference numerals in the drawings, and description thereof will be omitted. FIG. 8 shows a second embodiment of the present invention.
In the spinning device M 'according to this embodiment, the column 3 of the tube support unit 30 is replaced with the revolving mechanism of the first embodiment.
1 is provided with a motor 33 (rotating means). The chuck 33 is rotated at high speed around the axes L1 and L2 by the motor 33, so that the catalytic converter 10
It is designed to rotate around at high speed. The roll holder 61 of the roll support unit 40 is non-rotatably fixed to the column 41. Therefore, the roll 80 has the axis L
Reciprocation is performed in the radial direction at a predetermined angle along the circumferential direction around the two.

FIGS. 9 to 12 show a third embodiment of the present invention. As shown in FIG. 9, in the spinning device M ″ according to this embodiment, a disc-shaped cam 63 and the roll holder 61 are replaced with a roll-shaped cam 63 instead of the reciprocating mechanism 70 of the first embodiment. A motor 64 that rotates relatively around the axis L2 (revolution axis) with respect to the axis 61 is housed in the cam 63. As shown in Fig. 10, the cam 63 has three arc-shaped cam holes 63a. , The cam hole 63a and the guide slit 61 of the roll holder 61.
The shaft 74 is penetrated by a. by this,
When the motor 64 rotates the cam 63, the shaft 74 and thus the roll 80 are moved in the radial direction of the roll holder 61 (see FIG. 12). And three
So that two rolls 80 are always located on the same circumference,
They are to be moved together.

As shown in FIG. 9, the column 31 of the tube support unit 30 is composed of an outer cylinder 31a fixed to the base 20, and an inner cylinder 31b inserted through the outer cylinder 31a. Reciprocating means) and lead screw 3
5 expands and contracts. As a result, the chuck 32 and thus the catalytic converter 10 held by the chuck 32 are reciprocated up and down. The chuck 32 is adapted to be rotated by a motor 36 (second rotating means). This motor 36 is
This is different from the motor 33 in the second embodiment.

A spinning method using the spinning apparatus M ″ will be described. As shown in FIGS. 9 and 10, in the first step, the support column 31 is extended and the catalytic converter 10 is extended.
Is eccentric upward with respect to the axis L2 of the roll holder 61. Then, the roll 80 is moved to the motor 6 such that the radius of the innermost rotation locus C1 of the roll 80 is substantially equal to the radius of curvature of the minor diameter side of the converter main body 11.
2 (first rotating means). Further, the motor 32 drives the chuck 32 and thus the catalytic converter 10.
Is rotated at a speed much lower than the angular velocity of the roll 80 about the axis L2, and in a direction opposite to that of the roll 80. In synchronization with the rotation of the catalytic converter 10, the catalytic converter 10 is reciprocated up and down by the servomotor 34,
The converter body 11 always follows the rotation locus C1 of the roll 80. As a result, the roll 80 moves along the axis L2.
Is passed directly above the converter body 11 and is pressed against the converter main body 11, so that an annular groove 11c is formed in the converter main body 11.

As shown in FIG. 11, in the second step, the column 31 is contracted so that the axis L1 of the catalytic converter 10 coincides with the axis L2 of the roll holder 61. The chuck 32 is fixed without rotating. Further, the cam 6 is
Turn 3 to adjust the distance of the roll 80 from the axis L2 to the major radius of the catalytic converter 10 (see the phantom line in the figure).
Then, the roll 80 is rotated by the revolving mechanism 60, and is slid left and right by the slide mechanism 50 within the range of the processing target portion 11 b ′ of the converter main body 11. The rotation trajectory of the roll 80 draws a perfect circle, hits only the long-diameter portion of the processing target portion 11b ', and reduces the diameter of the long-diameter portion. Thereafter, the right end of the slide range of the roll 80 by the slide mechanism 50 is gradually shifted to the left, and the roll 80 is gradually approached to the axis L2 by the motor 64 so that the long diameter side portion of the processing target portion 11b 'is tapered. . When the diameter of the long diameter side portion is reduced to be equal to the short diameter, the roll 80 also hits the short diameter side portion. Thereafter, the diameter of the portion to be machined 11b 'is tapered and reduced over the entire circumference to form the tapered portion 11b.

In the second step, while the long-diameter portion of the processing target portion 11b 'is reduced in diameter until it becomes equal to the short-diameter, stress is applied to the short-diameter portion to increase the diameter. However, this stress is blocked by the annular groove 11c, and the raw pipe portion 11a
Will not be transmitted to Therefore, the deformation of the raw tube portion 11a can be prevented.

FIGS. 13 and 14 show a fourth embodiment of the present invention. In the fourth embodiment, a muffler 10 'for an internal combustion engine is formed using the same spinning device M as in the first embodiment, and the illustration of the device M is omitted. The tubular main body 11 'of the silencer 10' has an elliptical cross-section like the converter main body 11. When spinning the main body 11 ', the first step of the first embodiment is omitted, and only the second step is executed. That is, the processing target portion 11 is formed without forming the annular groove 11c.
b ′ is tapered. Even without the annular groove 11c, not only the long diameter side portion but also the short diameter side portion is reduced at a smaller ratio than the long diameter side portion, and the cross section gradually approaches a perfect circle, so that the base tube The deformation of the portion 11a can be prevented.

The present invention is not limited to the above embodiment, but can adopt various forms. For example, the reciprocating means may be a cam that operates in synchronization with the rotation of the rotating means (second rotating means). The moving means may be provided on the tube support unit 30. The holding means may be a clamp having a pair of holding members facing each other so as to be able to approach and separate from each other across the tube, and a clamping member for moving the holding members in the approaching direction and tightening the tube. In the first to third embodiments, the annular groove 11c of the first step is formed by another groove forming apparatus with a roll (for example, a muffler winding machine), and only the second step is the spinning apparatuses M, M ', and M ". In the third embodiment, in the second step as well as in the first step, the axis L is used.
1, L2 is eccentric, and the processing target portion 11b '
By pressing against the roll 80 along the rotation locus C1. In the third embodiment, the reciprocating means may be provided in the roll support unit 40. The term "elliptical" refers to a complete ellipse defined by geometry, as well as a round shape similar to a perfect ellipse (excluding perfect circles), for example, the minor axis is straight and the major axis is an arc of constant curvature. ) Is also included.

[0032]

As described above, in the first invention,
The pipe end is reduced not only at the long diameter side but also at the short diameter side at a smaller ratio than the long diameter side, and the cross section is processed so as to gradually approach a perfect circle. The deformation of the part can be prevented. In the second invention, the propagation of the stress applied from the roll to the end of the tube in the second step can be blocked by the annular groove, and the deformation of the tube portion other than the tube end can be prevented. According to the third and fourth aspects of the present invention, the roll is pressed against the end of the tube having an elliptical cross section to reduce not only the portion on the long diameter side but also the portion on the short diameter side, for example, an annular groove can be formed. The deformation of the base tube portion can be prevented. In the fifth invention, the pipe end can be formed to be tapered.

[Brief description of the drawings]

FIG. 1 is a front view showing a spinning device according to a first embodiment of the present invention in a state in which a first step is being performed;

FIG. 2 is a view taken along the line II-II in FIG.

FIG. 3 is a front view showing the device in a state where a first step is performed.

FIG. 4 is a front view showing the device in a state where a second step is performed.

FIG. 5 is a front view showing the catalytic converter according to the first embodiment in a completed state.

FIG. 6 is a side view of the catalytic converter.

FIG. 7 is an enlarged sectional view showing a main part of the catalytic converter.

FIG. 8 is a front view of a spinning device according to a second embodiment of the present invention.

FIG. 9 is a front view showing a spinning device according to a third embodiment of the present invention in a state where a first step is performed.

FIG. 10 is an arrow view along line XX in FIG. 9;

FIG. 11 shows a spinning device according to the third embodiment,
It is a front view shown in the implementation state of the 2nd process.

FIG. 12 is an arrow view along the line XII-XII in FIG. 11;

FIG. 13 is a front view showing a muffler according to a fourth embodiment of the present invention in a completed state.

FIG. 14 is a side view of the muffler.

[Explanation of symbols]

 M, M ', M "Spinning device (forming device) 11 Converter body (tube) 11' Silencer body (tube) 11c Annular groove 32 Chuck (gripping means) 33 Motor (rotating means) 34 Servo motor (reciprocating means) 36 Motor (second rotating means) 51 Servo motor (moving means) 62 Motor (rotating means, first rotating means) 71 Servo motor (reciprocating means) 80 Roll L1 axis L2 axis (revolution axis)

 ────────────────────────────────────────────────── ─── Continued on the front page (72) Inventor Jun Arai 292 Bessho, Ota-shi, Gunma Sakamoto Kogyo Co., Ltd. F-term (reference) 3G004 AA01 BA09 DA04 FA04 GA05 3H111 AA01 BA01 CB15 CB28 DB11 DB20 EA09

Claims (5)

[Claims] 1. A method for reducing the diameter of an end of a tube having an elliptical cross section, wherein a roll is relatively rotated around the tube and is pressed against the tube while relatively moving in the axial direction of the tube. By contacting, the major diameter of the pipe end is reduced toward the distal end, and the minor diameter of the tubular end is reduced at a rate smaller than the major diameter, so that the cross section of the distal end of the pipe is made substantially circular. Characteristic tube forming method. 2. A method for reducing the diameter of an end of a tube having an elliptical cross section, wherein a roll is pressed against the tube while relatively rotating around the tube to form an annular groove on the outer periphery of the tube. Forming a first step, and then rotating the same or another roll as in the first step relatively around the pipe and moving it relatively in the axial direction of the pipe, while moving the roll from the annular groove of the pipe to the tip. And a second step of reducing the diameter of the tube by pressing against the side. 3. An apparatus for reducing the diameter of an end of a tube having an elliptical cross-section, comprising: gripping means for gripping the tube; a roll disposed on an outer periphery of the tube; Rotating means for relative rotation to, and in synchronization with the rotating means,
A pipe forming apparatus comprising: a reciprocating means for reciprocating the roll in the radial direction of the pipe and continuously pressing the roll against the pipe. 4. An apparatus for reducing the diameter of an end of a tube having an elliptical cross-section, comprising: a roll; first rotating means for rotating the roll about a revolving axis remote from the roll; Gripping means for eccentrically gripping from, a second rotating means for rotating the gripping means around the axis of the tube, and synchronizing with the second rotating means, the gripping means in a direction orthogonal to the revolution axis. Reciprocating means for reciprocating relative to the revolving shaft, wherein the reciprocating means positions the pipe so as to follow the rotation locus of the roll and is pressed against the roll. Tube forming equipment. 5. The apparatus according to claim 3, further comprising moving means for relatively moving the roll in the axial direction of the tube.