JP4647056B2 - Tube forming method and forming apparatus - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a method and apparatus for reducing the diameter of a tube having an elliptical cross section.
[0002]
[Prior art]
For example, a main body of a catalytic converter or a silencer of an internal combustion engine often uses an elliptical cross-section tube in consideration of a mounting space in a vehicle. The tube for the main body has a larger diameter than the exhaust pipe having a perfect circular section as well as the long diameter, and the end of the main body pipe has a perfect circular cross section toward the tip. Thus, the diameter is reduced to a taper shape and connected to the exhaust pipe. In order to manufacture the main body tube having such a shape, first, a pair of molded products in which the tube is divided into two along one diameter is formed by pressing, and then these molded products are integrated by welding. Has been adopted.
[0003]
[Problems to be solved by the invention]
However, the conventional manufacturing method described above is inefficient because it requires two different types of work, pressing and welding. Therefore, there has been a demand to be able to manufacture by a spinning process in which a roll is pressed against a pipe and relatively rotated to reduce the diameter. However, the conventional spinning device corresponds to a tube having a perfect circular cross section, and the roll rotates around the axis of the tube so as to draw a perfect circle locus. When this device is applied to a tube having an elliptical cross section, the diameter of the tube end is reduced by hitting only the portion on the long diameter side of the tube end until the short diameter side portion becomes equal to the short diameter. Not processed. At this time, due to the effect of the reduced diameter of the long diameter side portion, the short diameter side portion is deformed to expand. This deformation is transmitted not only to the pipe end part to be processed but also to the other raw pipe part where the original elliptical shape should be maintained, resulting in a problem that the product shape is distorted.
The present invention has been made in view of the above circumstances, and the object of the present invention is to deform the raw tube portion other than the tube end portion when spinning the end portion of the tube having an elliptical cross section. There is no method and apparatus to provide.
[0004]
[Means for Solving the Problems]
In order to solve the above-mentioned problem, the first invention is a method for reducing the diameter of an end of a tube having an elliptical cross section, the roll is relatively rotated so as to draw an elliptical rotation locus around the tube , And while making a relatively round turn around the tube, it is continuously pressed against the end of the tube, and is also relatively strongly pressed against the long diameter side portion of the end of the tube, and the end of the tube minor axis of the press relatively weak against the portion Rutotomoni of, by relatively moving in the axial direction of the tube, causes a reduced diameter of the major axis of the tube end toward the distal end, the short tube end The diameter is reduced at a rate smaller than the major axis, and the cross-section of the tube tip is made substantially circular.
[0005]
A second invention is a method of reducing the diameter of an end of a tube having an elliptical cross section, and by pressing a roll against the tube while rotating it around the tube, an annular groove is formed on the outer periphery of the tube. And then rotating the same or another roll as in the first step around the tube and moving it in the axial direction of the tube while moving the roller relative to the annular groove of the tube. And performing a second step of pressing and reducing the diameter on the tip side.
[0006]
A third invention is an apparatus for reducing the diameter of an end of a tube having an elliptical cross section, the gripping means for gripping the tube, a roll disposed on the outer periphery of the tube, and an axis of the tube. Rotating means for relatively rotating around, reciprocating means for reciprocating the roll in the radial direction of the tube in synchronization with the rotating means, and moving means for relatively moving the roll in the axial direction of the tube The roll and the reciprocating means are continuously pressed against the end of the pipe while drawing an elliptical rotation trajectory while making a relatively round turn around the pipe, It is characterized in that it is relatively strongly pressed against the longer diameter side portion of the end portion of the tube and is relatively weakly pressed against the shorter diameter side portion of the end portion of the tube .
[0007]
A fourth invention is an apparatus for reducing the diameter of an end of a tube having an elliptical cross section, a roll, first rotating means for rotating the roll around a revolution axis away from the roll, and the revolution of the tube. A gripping means for gripping the shaft eccentrically, a second rotating means for rotating the gripping means around the axis of the tube, and a direction perpendicular to the revolution axis in synchronization with the second rotating means and reciprocating means for relatively reciprocating with respect to the revolution axis, the roll and a moving means for relatively moving in the axial direction of the tube, said tube by said reciprocating means in rotation locus of the roll It is positioned so as to follow and is pressed against the roll.
[0009]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, embodiments of the present invention will be described 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 subjected to spinning processing by a spinning device M (forming device).
[0010]
First, the catalytic converter 10 will be described. As shown in FIGS. 5 and 6, the catalytic converter 10 includes a converter main body 11 made of a steel pipe or the like, and a catalyst carrier 12 accommodated in the converter main body 11. The converter main body 11 has an elementary tube portion 11a having a uniform elliptical cross section (see FIG. 2), and a tapered portion 11b (tube end portion) extending from the elementary tube portion 11a. The taper portion 11b is spun by the spinning device M, and the cross section of the taper portion 11b decreases in diameter toward the tip, approaches a perfect circle, and becomes a perfect circle at the tip edge. As indicated by the phantom line in FIG. 7, the exhaust pipe 19 having a perfect circular cross section is connected to the tip edge.
[0011]
As shown in FIGS. 2 and 5, the catalyst carrier 12 is a catalyst in which a catalyst is supported on a honeycomb structure having a lattice shape, and an outer periphery of the catalyst carrier 12 is accommodated in the raw tube portion 11 a with an elliptical shape. . A holding mat 13 (holding material) made of ceramic fibers or the like is interposed between the outer periphery of the catalyst carrier 12 and the inner periphery of the raw tube portion 11a.
[0012]
The spinning device M will be described.
As shown in FIG. 1, the apparatus M includes a base 20, a tube support unit 30 disposed on the right side of the base 20, and a roll support unit 40 disposed on the left side. The tube support unit 30 includes a column 31 standing on the base 20 and a chuck 32 (gripping means) fixed to the upper end of the column 31. The catalytic converter 10 before being subjected to the spinning process is held by the chuck 32 with the axis L1 facing left and right. As shown in FIGS. 1 and 2, the converter body 11 before processing has a uniform elliptical cross section over its entire length, and a catalyst carrier 12 and a holding mat 13 are accommodated therein in advance.
[0013]
The roll support unit 40 includes a slide mechanism 50 provided on the base 20, a revolving mechanism 60 provided on the slide mechanism 50, three reciprocating mechanisms 70 provided on the revolving mechanism 60, and these reciprocating movements. And three rolls 80 provided in the mechanism 70.
[0014]
The slide mechanism 50 includes a servo motor 51 (moving means) fixed to the base 20 and a slider 52 slidably attached to the base 20. A lead screw 53 is connected to the servo motor 51, and a guide nut 54 is screwed to the lead screw 53. This guide nut 54 is fixed to the slider 52. As a result, the lead screw 53 is rotated by the servo motor 51, the guide nut 54 and the slider 52 are slid left and right, and the roll 80 is moved left and right.
[0015]
A support column 41 is erected on the slider 52, and the revolution mechanism 60 is provided at the upper end of the support column 41. The revolution mechanism 60 includes a hollow disc-shaped roll holder 61 that is rotatably supported by the support column 41, and a motor 62 (rotating means) coupled 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 roll holder 61 is rotated at high speed around the axis L2 by the motor 62, and as a result, the roll 80 is rotated at high speed (revolved) around the axis L2.
[0016]
The three reciprocating mechanisms 70 are arranged 120 degrees apart in the circumferential direction of the roll holder 61. 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 connected to the servo motor 71 and accommodated in the roll holder 61 in the radial direction. A lead screw 72, a guide nut 73 screwed into the lead screw 72, and a shaft 74 provided on the guide nut 73. The shaft 74 protrudes toward the tube support unit 30 through a guide slit 61 a formed on the right side plate of the roll holder 61. The roll 80 is provided at the tip of the shaft 74. As a result, the lead screw 72 is rotated by the servo motor 71, and the guide nut 73 and the roll 80 are reciprocated in the radial direction of the roll holder 61.
The roll 80 can be rotated (rotated) around the axis of the shaft 74.
[0017]
A method of spinning the catalytic converter 10 by the spinning device M configured as described above will be described.
As shown in FIG. 1 to FIG. 3, the spinning process includes a first step of forming a tubular groove 11 c at the boundary with the raw pipe portion 11 a in the processing target portion 11 b ′ (tube end portion) to be the tapered portion 11 b, As shown in FIG. 4, it consists of the 2nd process which tapers the process target part 11b 'of the front end side from the tubular groove | channel 11c after that.
[0018]
The first step will be described. First, as shown in FIGS. 1 and 2, the roll 80 is positioned on the radially outer side of the boundary of the processing target portion 11 b ′ by the slide mechanism 50. Then, the roll 80 is rotated around the axis L2 by the revolution 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 body 11. That is, the roll 80 is caused to draw an elliptical rotation locus along the converter main body 11. Thereby, as shown in FIG. 3, an annular groove 11 c is formed in the converter main body 11. The annular groove 11c is located on the tip side (left side) of the catalyst carrier 12.
[0019]
Subsequently, the second step is performed. In this step, in addition to the synchronous operation of the revolving mechanism 60 and the reciprocating mechanism 70, the roll 80 is slid in the left-right direction by the slide mechanism 50. Initially, 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 front end edge (left end edge) of the converter body 11. Then, the right end of the slide operation range is gradually shifted to the tip side of the processing target portion 11b ′. As a result, as shown in FIG. 4, the processing target portion 11 b ′ on the tip side from the annular groove 11 c is tapered.
[0020]
Moreover, the reciprocating mechanism 70 allows the roll 80 to be pressed relatively strongly when facing the major axis side of the converter main body 11 and relatively weakly pressed when facing the minor axis side. . As a result, the reduction ratio of the short diameter side is smaller than that of the long diameter side. As a result, as shown in FIG. 6, the cross section of the processing target portion 11 b ′ approaches a perfect circle toward the tip, and becomes a perfect circle at the tip edge. In this way, the taper part 11b is shape | molded. As shown in FIG. 7, the annular groove 11c becomes a step 11c ′. This step 11 c ′ protrudes radially inward from the outer peripheral edge of the catalyst carrier 12.
[0021]
In this second step, not only the long diameter side portion of the processing target portion 11b ′ but also the short diameter side portion is reduced in diameter at a rate smaller than the long diameter side portion, and the cross section is gradually brought closer to a perfect circle. Can be prevented from being deformed. In addition, since the stress applied from the roll 80 to the workpiece 11b ′ can be blocked by the annular groove 11c (or step 11c ′) and can be prevented from being transmitted to the tube 11a, the deformation of the tube 11a is further ensured. Can be prevented. As a result, it is possible to prevent the catalyst carrier 12 in the raw tube portion 11a from being damaged.
[0022]
Thereafter, the left and right directions of the converter body 11 are reversed and mounted on the chuck 32. As shown in FIG. 5, the taper portion 11b is also formed on the opposite end (right end) of the converter body 11 in the same manner as described above. Mold. As a result, the catalytic converter 10 is completed and incorporated in the internal combustion engine and mounted on the vehicle.
[0023]
The catalytic converter 10 mounted on this vehicle has the following effects. That is, as shown in FIG. 7, the step 11 c ′ protrudes inward in the radial direction from the holding mat 13, so that the exhaust gas sent from the exhaust pipe 19 is prevented from blowing strongly 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. Furthermore, since the step 11c ′ protrudes 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 vehicle vibration or the like.
[0024]
Next, another embodiment of the present invention will be described. In the following embodiments, the same configurations as those of the first embodiment are denoted by the same reference numerals in the drawings and the description thereof is omitted. FIG. 8 shows a second embodiment of the present invention. In the spinning device M ′ according to this embodiment, a motor 33 (rotating means) is provided on the column 31 of the tube support unit 30 instead of the revolution mechanism of the first embodiment. By this motor 33, the chuck 32 is rotated at high speed around the axis lines L1 and L2, and as a result, the catalytic converter 10 is rotated at high speed around the axis line L1. The roll holder 61 of the roll support unit 40 is fixed to the support column 41 so as not to rotate. Therefore, the roll 80 reciprocates in the radial direction at a predetermined angle along the circumferential direction around the axis L2.
[0025]
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, instead of the reciprocating mechanism 70 of the first embodiment, a disc-shaped cam 63 and a cam 63 are installed in the roll holder 61. A motor 64 that rotates around an axis L2 (revolution axis) with respect to 61 is accommodated in the cam 61. As shown in Fig. 10, the cam 63 is formed with three cam holes 63a having an arc shape. The shaft 74 passes through the cam hole 63a and the guide slit 61a of the roll holder 61. Thus, when the motor 64 rotates the cam 63, the shaft 74 and the roll 80 are moved in the radial direction of the roll holder 61. In addition, the three rolls 80 are moved together so that they are always located on the same circumference.
[0026]
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, and a servo motor 34 (reciprocating means). ) And the lead screw 35. As a result, the chuck 32 and eventually the catalytic converter 10 gripped by the chuck 32 are reciprocated up and down. The chuck 32 is rotated by a motor 36 (second rotating means). The motor 36 is different from the motor 33 in the second embodiment.
[0027]
A spinning method using the spinning device M ″ will be described.
As shown in FIGS. 9 and 10, in the first step, the support column 31 is extended, and the axis L <b> 1 of the catalytic converter 10 is decentered upward with respect to the axis L <b> 2 of the roll holder 61. Then, the roll 80 is rotated by the motor 62 (first rotating means) so that the radius of the innermost rotation locus C1 of the roll 80 is substantially equal to the radius of curvature on the short diameter side of the converter body 11. Further, the chuck 32 and the catalytic converter 10 are rotated by the motor 36 at a speed much lower than the angular velocity around the axis L <b> 2 of the roll 80 and in the direction opposite to the roll 80. In synchronization with the rotation of the catalytic converter 10, the servo converter 34 reciprocates the catalytic converter 10 up and down so that the converter main body 11 always follows the rotation locus C 1 of the roll 80. As a result, when the roll 80 passes right above the axis L2, it is pressed against the converter body 11, and an annular groove 11c is formed in the converter body 11.
[0028]
As shown in FIG. 11, in the second step, the support column 31 is contracted so that the axis L <b> 1 of the catalytic converter 10 coincides with the axis L <b> 2 of the roll holder 61. The chuck 32 is fixed without rotating. Further, the cam 64 is rotated by the motor 64, and the distance from the axis L2 of the roll 80 is adjusted to the long radius of the catalytic converter 10 (see the phantom line in the figure). Then, the roll 80 is rotated by the revolution mechanism 60 and is slid left and right within the range of the processing target portion 11b ′ of the converter main body 11 by the slide mechanism 50. The rotation locus of the roll 80 draws a perfect circle and hits only the portion on the long diameter side of the processing target portion 11b ′, thereby reducing the diameter of the long diameter side portion. Thereafter, the right end of the slide range of the roll 80 by the slide mechanism 50 is gradually shifted to the left side, and the roll 80 is gradually brought closer to the axis L2 by the motor 64 so that the longer diameter side portion of the processing target portion 11b ′ is tapered. . When the diameter of the long diameter side portion is reduced until it becomes equal to the short diameter, the roll 80 also hits the short diameter side portion. Thereafter, the taper portion 11b is formed by tapering the diameter of the object to be processed 11b ′.
[0029]
In this second step, while the diameter of the long diameter side portion of the processing target portion 11b ′ is reduced until it becomes equal to the short diameter, stress that expands the diameter acts on the short diameter side portion. However, this stress is interrupted by the annular groove 11c and is not transmitted to the raw tube portion 11a. Therefore, deformation of the raw tube portion 11a can be prevented.
[0030]
13 and 14 show a fourth embodiment of the present invention. In the fourth embodiment, the silencer 10 'of the 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 similar to 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 11b ′ is tapered without forming the annular groove 11c. Even without the annular groove 11c, not only the long diameter side portion of the processing target portion 11b 'but also the short diameter side portion is reduced in diameter at a rate smaller than that of the long diameter side portion, and the cross section is gradually brought closer to a perfect circle. It is possible to prevent the portion 11a from being deformed.
[0031]
The present invention is not limited to the above-described embodiment, and various forms can be adopted.
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 in the tube support unit 30.
The gripping means may be a clamp having a pair of clamping members that face each other so as to be able to approach and separate, and a clamping member that moves the clamping members in the approaching direction and clamps the tube.
In the first to third embodiments, the annular groove 11c in the first step is formed by another roll-formed groove forming device (for example, a muffler winding machine), and only the second step is performed by the spinning devices M, M ′, M ″. It may be executed with.
In the third embodiment, in the second step, as in the first step, with the axes L1 and L2 being decentered, the processing target portion 11b ′ is pressed against the roll 80 along the rotation locus C1, It may be tapered. In the third embodiment, the reciprocating means may be provided in the roll support unit 40.
“Ellipse” means a round shape similar to a perfect ellipse (excluding a perfect circle), such as a perfect ellipse defined by geometry, for example, the minor axis is linear and the major axis is an arc of constant curvature. ) Is also included.
[0032]
【The invention's effect】
As described above, in the first invention, the tube end portion is reduced not only in the long diameter side portion but also in the short diameter side portion at a rate smaller than the long diameter side portion so that the cross section gradually approaches a perfect circle. Therefore, deformation of the raw pipe portion other than the pipe end portion can be prevented.
In the second invention, propagation of stress applied from the roll to the end of the pipe in the second step can be blocked by the annular groove, and deformation of the raw pipe part other than the pipe end can be prevented.
In the third and fourth inventions, the roll is pressed against the end of the elliptical cross-section tube, and not only the longer diameter portion but also the shorter diameter portion can be reduced in diameter, for example, an annular groove can be formed. Deformation of the raw tube portion can be prevented.
In the fifth invention, the tube end can 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 of preparation for performing a first step.
FIG. 2 is a view taken along the line II-II in FIG.
FIG. 3 is a front view showing the apparatus in an implementation state of a first step.
FIG. 4 is a front view showing the apparatus in an implementation state of a second step.
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 cross-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 an implementation state of a first step.
10 is a view taken along the line XX of FIG. 9;
FIG. 11 is a front view showing the spinning device according to the third embodiment in a state where the second step is performed.
12 is a view taken along the line XII-XII in FIG.
FIG. 13 is a front view showing a silencer according to a fourth embodiment of the present invention in a completed state.
FIG. 14 is a side view of the silencer.
[Explanation of symbols]
M, M ', M "Spinning device (Molding device)
11 Converter body (pipe)
11 'silencer body (pipe)
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)

Claims (4)

  A method of reducing the diameter of an end of a tube having an elliptical cross section, in which a roll is relatively rotated so as to draw an elliptical rotation trajectory around the tube, and while relatively rounding the periphery of the tube, Press continuously against the end of the tube, press relatively strongly against the longer diameter side of the end of the tube, and press relatively weakly against the shorter diameter side of the end of the tube In addition, by moving relatively in the axial direction of the tube, the major axis of the tube end is reduced toward the tip, and the minor axis of the tube end is reduced at a rate smaller than the major axis, thereby A method of forming a tube, characterized in that the cross-section of the tip is substantially a perfect circle.   A method of reducing the diameter of an end of a tube having an elliptical cross section, the first step of forming an annular groove on the outer periphery of the tube by pressing a roll against the tube while relatively rotating around the tube After that, the same or other roll as in the first step is rotated around the tube and is relatively moved in the axial direction of the tube while being pressed and contracted toward the tip side from the annular groove of the tube. A method for forming a tube, comprising performing a second step of making a diameter. A device for reducing the diameter of an end of a tube having an elliptical cross section, a gripping means for gripping the tube, a roll disposed on the outer periphery of the tube, and a rotation for relatively rotating the roll around the axis of the tube Means, and reciprocating means for reciprocating the roll in the radial direction of the tube in synchronization with the rotating means, and moving means for relatively moving the roll in the axial direction of the tube , the rotating means and By the reciprocating means, the roll is continuously pressed against the end of the tube while drawing an elliptical rotation trajectory while making a relatively round turn around the tube, and the end of the tube An apparatus for forming a pipe, characterized in that it is relatively strongly pressed against a part on the long diameter side and is relatively weakly pressed against a part on the short diameter side of the end of the pipe. A device 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 around a revolution axis away from the roll; and gripping the pipe eccentrically from the revolution axis Gripping means, second rotating means for rotating the gripping means around the axis of the tube, and synchronizing the gripping means with respect to the revolution axis in a direction perpendicular to the revolution axis. and reciprocating means for relatively reciprocating Te, the roll and a moving means for relatively moving in the axial direction of the tube, the tube is positioned so accompany the rotation locus of the roll by the reciprocating means, An apparatus for forming a tube, wherein the apparatus is pressed against the roll.

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