WO2006115205A1

WO2006115205A1 - Method and device for molding uneven wall thickness tube

Info

Publication number: WO2006115205A1
Application number: PCT/JP2006/308427
Authority: WO
Inventors: Yoshihiro Saito; Katsuhiro Nojima; Kunio Nagata; Hiroyuki Nakano; Akihiro Nagata
Original assignee: Central Motor Wheel Co., Ltd.
Priority date: 2005-04-22
Filing date: 2006-04-21
Publication date: 2006-11-02
Also published as: JP2006297465A

Abstract

A method of molding an uneven wall thickness tube capable of molding an uneven wall thickness tube having a partially thin-walled peripheral part from a cylindrical raw tube with approximately uneven wall thickness, a method of manufacturing a wheel rim for a vehicle molded from the uneven wall thickness tube, and an uneven wall thickness tube molding device. In the method of molding the uneven wall thickness tube, the uneven wall thickness tube (X) having the thin-walled peripheral part (Y) of a prescribed width is molded by loosely fitting a plurality of pressing rolls (20a) to (20f) having pressing projected parts (22a) to (22f) increased in width stepwise formed on all the periphery thereof to a mandrel roll (2) in the order of increasing in width and pressing the pressing projected parts (22a) to (22f) against the rotating cylindrical raw tube (x) to form thin-walled peripheral parts (y1) to (y6) stepwise. The method of manufacturing the wheel rim comprises a step for molding the uneven wall thickness tube (X). The device (1) materializes the molding method. Thus, the wheel rim with uneven wall thickness can be manufactured while the productivity of normal wheel rims is maintained.

Description

Specification

TECHNICAL FIELD OF THE INVENTION

[0001] In the present invention, a cylindrical element pipe having a substantially uniform wall thickness is thinned at a predetermined portion along the axial direction in the circumferential direction, so that it has a portion having a partially different thickness. Method for forming unequal thick tube for forming equal thickness pipe, method for manufacturing vehicle wheel rim for forming unequal thickness pipe force, and unequal thickness pipe forming apparatus capable of forming unequal thickness pipe It is about.

Background art

[0002] For example, a two-piece wheel having a structure in which a wheel rim and a wheel disc are welded is well known as a vehicle wheel. Here, the wheel rim is usually formed by bending a rectangular metal plate having a substantially uniform thickness so that the short sides of both sides abut against each other, and then abutting and welding to form a cylindrical element tube. After that, it is generally formed into a desired shape by roll processing that is clamped with a predetermined mold from inside and outside of the raw tube. Note that, as the cylindrical element pipe for forming the wheel rim, generally, a pipe having a shorter axial length (pipe length) than the diameter of the element pipe is used.

Meanwhile, in recent years, there is a strong demand for weight reduction of vehicle wheels. For this reason, various manufacturing methods have been proposed in which wheel rims are formed by partially thinning (hereinafter referred to as unequal wall thickness) portions in the axial direction that have sufficient strength. Yes. As described above, as a forming method for unevenly thickening the wheel rim, there is a method in which a predetermined portion is cut and thinned after forming a cylindrical tube or after forming into a rim shape. is there. In addition, after thinning in advance in the state of the metal plate where the site with a strong margin is formed, the short sides of the metal plate are abutted and welded to form an unequal thick tube, A manufacturing method has been proposed in which this is rolled (for example, Patent Document 1). Furthermore, a method has been proposed in which a predetermined portion is thinned by flow-turning a substantially uniform cylindrical element pipe (for example, Patent Document 2). Here, as a flow taring process, This is a process of partially thinning the cylindrical element tube by rolling a predetermined roll along the direction of the outer force axis.

Patent Document 1: Japanese Unexamined Patent Application Publication No. 2004-230919

Patent Document 2: Japanese Translation of Special Publication 2004-522636

Disclosure of the invention

Problems to be solved by the invention

[0004] However, in the above-described forming method for increasing the thickness of the wheel rim of the vehicle wheel, the cutting method has a low material yield, requires processing of cutting waste, There are problems such as a decrease in rim productivity due to the time required for processing. In addition, in the method of forming an unequal thick tube by bending a partially thinned metal plate in advance, the welded portion where the short sides of the metal plate are welded together is formed in an uneven surface shape along the axial direction. Is done. For this reason, there is a problem that it is difficult to form the welded portion after the processing, which makes it difficult to perform the trimming processing of the welded portion along the uneven surface. . Furthermore, in the method of uneven thickness increase by the flow turner cache, there is a problem that the yield is high because there is no cutting waste as in the above-described cutting, but the productivity is long and the productivity is low. is there.

[0005] Therefore, there is a strong demand for a technology that can exhibit excellent yield and high productivity in the production process of unequal-thick rims in the production process of unequal-thickness rims in the rim production process for vehicle wheels. Has been. The present invention provides an unequal-thickness tube forming method, an unequal-thickness pipe forming apparatus, and an unequal-thickness tube forming method that can meet such demands and make a substantially uniform-thickness cylindrical element tube unequally thick Thick tube force It is aimed to provide a wheel rim forming method for forming a wheel rim.

Means for solving the problem

[0006] In the present invention, a cylindrical element tube is loosely fitted to a mandrel roll, and the cylindrical element tube is rotated by the rotation of the mandrel roll, so that the pressing width is gradually increased in the arrangement order. In accordance with the order, the plurality of pressing rolls are sequentially moved to positions where the pressing protrusions configured with the respective pressing widths are in pressure contact with the cylindrical element tube, and at least the cylindrical element tube is at least During one rotation, the pressing protrusion of each pressing roll is kept pressed against the cylindrical element tube. By repeating the movement of each pressing roll and maintaining the pressure, the thin peripheral portion was formed to gradually widen in steps, and an unequal thick tube having a thin peripheral portion of a predetermined width was formed. This is a method for forming an unequal thick-walled tube. Here, it is preferable that each pressing roll is pressed into the cylindrical element tube such that the width direction of the pressing width of the pressing protrusion is along the axial direction of the cylindrical element tube. Thereby, the width direction of the thin peripheral part formed in a cylindrical element pipe turns into the axial direction of this element pipe.

[0007] It should be noted that when the cylindrical roll is pressed, the pressing roll has a circumferential speed substantially the same as the circumferential speed of the mandrel roll in a direction opposite to the rotation direction of the mandrel roll so as to assist the rotation of the blank pipe. It is preferable that it is driven by. Thereby, pressing can be performed smoothly.

[0008] According to the method of applying force, the cylindrical peripheral tube is pressed in the order in which the pressing widths of the plurality of pressing rolls are increased, so that the thin peripheral portion is expanded stepwise to a predetermined width. It can be formed to form the desired unequal thick-walled tube.

Here, the pressing protrusion of each pressing roll is provided with each pressing width set so as to form the thin peripheral portion in multiple stages up to a predetermined width. The processing dimension along the axial direction (hereinafter referred to as the processing width) pressed by the individual pressure rolls can be made sufficiently shorter than the axial length of the cylindrical element tube (hereinafter referred to as the tube length). is there. In other words, in the pressing process with each pressing roll, only a part is processed with respect to the entire length (pipe length) that is extremely small compared to the dimension of the unprocessed part when viewed in the axial direction. That's it! /

[0010] Accordingly, the circumferential force of the portion subjected to the pressing force is restrained by the non-force portion, so that the inner diameter of the cylindrical element tube can hardly be changed by the pressing. As a result, the material removed by the formation of the thin perimeter flows in the axial direction of the tube and causes the thin perimeter to stretch in the axial direction. That is, the tube length of the cylindrical element tube is extended by the pressing process.

[0011] Therefore, according to the molding method of the present invention, it is desired that the cylindrical inner tube has a thin peripheral portion with a predetermined width and the tube length is increased without substantially changing the inner diameter of the tube. It is possible to form a non-uniformly thick tube. The length extending in the axial direction in advance (hereinafter referred to as the shaft) The material size (material area forming the circumference of the tube and the tube length, hereinafter referred to as the basic unit) that forms the cylindrical tube (before processing) It can also be reduced.

[0012] Further, in the pressing process using the individual pressing rolls, rolling is performed in the circumferential direction with respect to a partial region (processing width) in the axial direction of the cylindrical element tube in accordance with the rotation. Yes. Therefore, the processing area where the pressing protrusion of the pressing roll contacts the cylindrical element tube (the above-described processing width X contact length in the circumferential direction) is extremely small, and a desired pressing process is performed according to the processing area. Load (hereinafter referred to as pressing force) is also reduced. As a result, the present invention makes it possible to make the device for exerting this pressing force relatively small. Furthermore, the processing time required for pressing by each pressing roll can be shortened sufficiently by increasing the peripheral speed of rotating the cylindrical element tube. The processing time until the tube is formed is shortened.

On the other hand, according to the present invention, as a method for manufacturing a wheel rim for a vehicle, a cylindrical element tube is loosely fitted to a mandrel roll, and the cylindrical element tube is rotated by rotation of the mandrel roll. A plurality of pressing rolls set so that the pressing width is expanded stepwise along the order is sequentially moved to a position where the pressing protrusion configured to each pressing width presses the cylindrical element tube in accordance with the order. By moving and holding the pressing protrusion of each pressing roll on the cylindrical element tube while the cylindrical element tube rotates at least once, by repeating the movement and pressing maintenance of each pressing roll, A method characterized by comprising an unequal thick tube forming step of forming an unequal thick tube having a thin peripheral portion of a predetermined width by forming the portion to be gradually widened in steps. is there.

[0014] In the method that works, the wheel rim for a vehicle is manufactured using an unequal thick tube obtained by the same molding process as the unequal thick tube forming method described above. In addition, it is possible to form a wheel rim having an unequal wall thickness by partially thinning a predetermined portion having sufficient strength as a vehicle wheel. Therefore, it is possible to manufacture a vehicle wheel that is reduced in weight while maintaining sufficient strength and durability. In addition, as described above, since the basic unit of the material can be reduced, the manufacturing cost can be reduced. In addition, since unequal wall thickness pipes can be formed in a relatively short time, a circle with an almost uniform wall thickness is obtained. It is possible to maintain substantially the same productivity as in the normal case of molding from a tube.

[0015] Further, as a substantial forming apparatus of the above-described unequal thick-walled tube forming method, the present invention includes a mandrel roll in which a cylindrical element tube is loosely fitted and rotated to rotate the element tube, A plurality of pressing members for forming a thin peripheral portion with a predetermined width on the raw pipe are sequentially pressed from the outside to the cylindrical raw pipe loosely fitted on the mandrel roll. A group of pressing rolls, each of which is set so that the pressing width gradually increases until the pressing protrusion of each pressing roll becomes a thin peripheral portion having a predetermined width along the arrangement order thereof. A roll revolving member that supports the press roll group so as to be able to rotate in the circumferential direction by a permutation in which the press widths of the press protrusions of the press rolls sequentially expand, so that all the press rolls can rotate integrally, and It is provided approximately parallel to the mandrel roll, and the roll revolving member is externally fitted. The pressure outer peripheral surface of each pressure roll is in contact with the mandrel roll, and the pressure support roll that sandwiches the cylindrical element tube with the mandrel roll via the pressure roll; The position is sequentially changed so that the pressing width is expanded to the pressing position where the cylindrical element pipe is pressed against the mandrel roll, and each pressing roll is moved to the cylinder at the pressing position while the cylindrical element pipe is rotated at least once. And a rotation drive control device for driving the roll revolving member to rotate so as to press the shaped element tube. Here, the revolving member is a member that integrally revolves a plurality of pressing rolls, and is similar to a cage in a planetary mill.

[0016] In the unequal thick tube forming apparatus having a powerful configuration, the cylindrical base tube is loosely fitted to the mandrel roll and rotated, and the pressing rolls are sequentially moved to the pressing positions in the order in which the pressing widths are increased. By performing the next conversion, the cylindrical element tube is pressed at the pressing position, and the thin peripheral portion is formed so as to be gradually widened to a predetermined width so that a desired unequal thickness tube can be formed. is there. Each pressing roll is preferably arranged on the roll revolving member so that the width direction of the pressing width of the pressing protrusion is substantially along the axial direction of the cylindrical element tube. Thereby, the width direction of the thin-walled peripheral portion formed by pressing the pressing roll is the axial direction of the cylindrical element tube.

[0017] Here, as described above, the unequal thick-walled tube forming apparatus performs the pressing process on the cylindrical element tube in multiple stages by the plurality of pressing rolls constituting the pressing roll group. thing Thus, the processing width (processing dimension in the axial direction) pressed by each pressing roll can be reduced. As a result, as described above, since the processing width is sufficiently shorter than the tube length of the cylindrical element tube, stretching in the circumferential direction is restricted by the pressing force of each pressing roll. This will cause stretching in the axial direction. Therefore, it is possible to form a desired unequal-thickness tube that has a thin peripheral portion with a predetermined width and has a long tube length (length in the axial direction) without changing the inner diameter of the cylindrical tube. You can get.

[0018] Further, as described above, since the processing area at the time of pressing with individual pressing rolls is small, the pressing force can be reduced, and the device that exhibits the pressing force can be downsized. That is, the unequal thick-walled tube forming apparatus of the present invention is relatively small. Furthermore, the mandrel roll and the pressure support roll are rotated at a high speed to increase the peripheral speed of the cylindrical tube, and in addition to the rotation, the roll revolving member also sequentially converts each press roll to the pressing position. Can be made faster. Therefore, a desired unequal thickness tube can be formed in a short time. Thus, the unequal thick tube forming apparatus of the present invention can exhibit high productivity as compared with the above-described forming method of the conventional configuration.

[0019] The unequal thick-walled tube forming apparatus of the present invention can be applied to the production of a wheel rim in which a portion having no influence on the strength of the vehicle wheel is thinned by being applied to a vehicle wheel rim production line. it can. For example, the unequal thick-walled tube forming apparatus is disposed immediately after the step of forming a cylindrical element pipe by welding the short sides of a metal plate, and a predetermined portion is thinned from the cylindrical element pipe. Form an equal thickness tube. Then, this unequal thickness tube is formed into a partially thinned wheel rim having an unequal thickness shape by a roll forming process. In such a rim production line, the unequal-thickness tube forming apparatus of the present invention exhibits high productivity for forming unequal-thickness pipes in a short time, and a wheel rim having a substantially uniform wall thickness can be obtained. It is possible to form a lightweight wheel rim while maintaining almost the same productivity as a normal production line. Furthermore, since the unequal thick tube is formed by increasing the tube length of the cylindrical raw tube by the unequal thick tube forming device, the length that extends in the axial direction (a widening amount of the rim width) is previously set. By considering the length of the cylindrical pipe in consideration, the basic unit of the metal plate forming the cylindrical pipe can be reduced. In addition, since the unequal-thickness pipe forming apparatus of the present invention forms a cylindrical raw pipe force unequal-thickness pipe, as described above, In the production line, it can be arranged just before the roll forming kayaking process. For this reason, it is possible to perform the process of welding the short sides of a metal plate and the process of trimming the welded part in a normal process, and the welded portion can be processed into a smooth surface property.

[0020] In the unequal thick tube forming apparatus described above, the axial position of the cylindrical element tube loosely fitted to the mandrel roll is determined, and the axial direction of the cylindrical element tube generated by pressing the pressing roll is determined. A configuration is proposed that is provided with positioning means that does not hinder the stretching deformation of the!

[0021] With such a configuration, the positioning unit can accurately determine the axial position of the cylindrical element tube with respect to the pressing protrusion of the pressing roll, and the thin peripheral portion can be reliably positioned at the desired axial position. Can be molded. In addition, as described above, the unequal-thickness tube forming apparatus causes stretching deformation that lengthens the tube length by pressing the pressing roll. Here, if the extension deformation in the axial direction is hindered, not only the axial extension length is restricted, but also a large load is applied to each tool during the pressing process, or a part that is being pressed. Problems such as local deformation in the vicinity can occur. Therefore, by making the positioning means not hinder the stretching deformation of the tube length, it is possible to appropriately form an unequal thick tube having a desired shape.

[0022] Further, in the above-described unequal thick-walled tube forming apparatus, the mandrel roll and the pressing support roll on which the pressing roll is mounted by the roll revolving member can be inserted into and removed from the cylindrical element tube. And a configuration including a position converting means for converting the cylindrical element tube loosely fitted to the mandrel roll into a processing position that can be pressed by a pressing hole at the pressing position.

[0023] By virtue of the powerful configuration, after the cylindrical element tube is loosely fitted to the mandrel roll at the separation position, the pressing process is performed to change the position to the processing position to form a thin peripheral portion, and the position is changed to the separation position again. In other words, a series of steps of removing the mandrel roll force from the unequal thick tube after the caulking will be performed smoothly and easily. Here, the position conversion means may be one that converts the position of either the mandrel roll or the pressure support roll, or may be one that converts the position of both.

[0024] Further, in the unequal thick-walled tube forming apparatus described above, the cylindrical element tube is provided on both sides of the pressing position where the cylindrical element tube and the pressing roll are clamped by the mandrel roll and the pressing support roll. A configuration with a tube presser roll that presses against a mandrel roll is proposed.

[0025] In such a configuration, the tube holding roll presses the cylindrical element tube against the mandrel roll on both sides of the pressing position, so that the inner peripheral surface of the cylindrical element tube is moved by the mandrel roll near the pressing position. It can be supported sufficiently. Therefore, it is possible to sufficiently prevent the inside of the tube from being deformed by the pressing force. Furthermore, it also has an effect of restraining the raw pipe from extending in the circumferential direction by pressing. In addition, the mandrel roll can rotate the cylindrical element tube stably at a predetermined rotation speed during the pressing process by the pressing roll, and even when rotating at a high speed, stable and high productivity can be achieved. Can be maintained.

[0026] Further, in the unequal thick-walled tube forming apparatus described above, the pressing protrusions of the pressing roll are provided with inclined peripheral surfaces that are inclined so as to be flared on both sides thereof. A configuration is proposed.

[0027] In such a configuration, the thin peripheral portion formed by each pressing roll has a cross-sectional shape along the axial direction that is trapezoidal with the axial width narrowing inward in the roll radial direction. I am doing so. By forming the thin peripheral portion of this trapezoidal cross section, the pressing process of the next pressing roll makes it easier to further widen the thin peripheral portion in the axial direction. Therefore, even when each roll is rotated at a high speed as described above, the pressing process using a plurality of pressing rolls can be executed more smoothly. If the pressing protrusion is not formed with an inclined peripheral surface and both sides are formed substantially perpendicular to the outer peripheral surface of the roll, a thin peripheral portion with a rectangular cross section is formed. Is done. In this case, there is a concern that when the next pressing roll is pressed, both sides of the thin peripheral portion are deformed so as to be pressed inside the peripheral portion. In this configuration, it is possible to prevent such cover deformation.

[0028] On the other hand, in the unequal thick-walled tube forming apparatus described above, the roll revolving member aligns each pressing roll with one side end of each pressing protrusion, and the pressing width expands to the other side. A configuration is proposed in which it is arranged around the pressure support roll.

[0029] In this configuration, the cylindrical element tube is stretched and deformed to one side in the axial direction by pressing.

[0030] Alternatively, the roll revolving member has each pressing roll, and the pressing width of each pressing protrusion is on both sides. The structure which arrange | positions the circumference | surroundings of a press support roll so that it may spread to is proposed.

[0031] In this configuration, the cylindrical element tube is stretched and deformed on both sides in the axial direction by pressing.

The invention's effect

[0032] As described above, in the present invention, the cylindrical protrusions loosely fitted to the mandrel rolls are rotated, and the pressing protrusions each having a pressing width that gradually increases in the arrangement order are formed. The plurality of pressing rolls are sequentially moved in accordance with the order of the pressing protrusions to a position where the pressing protrusions are in pressure contact with the cylindrical element tube, and the pressing protrusions are moved to the cylinder while the cylindrical element tube rotates at least once. By maintaining the pressure on the tube and repeating the movement and pressure maintenance of each pressing roll, the thin peripheral portion is formed so as to gradually widen in steps, and the unequal thickness having the thin peripheral portion of a predetermined width. Since this is a forming method that forms a tube, it has a thin peripheral part with a predetermined width and a long tube length from a substantially uniform cylindrical element tube with almost no change in the inner diameter of the element tube. The desired unequal thick-walled tube can be formed. In addition, the processing area (axial processing dimension X contact length in the circumferential direction) due to the individual pressing rolls is small! This makes it possible to reduce the pressing force, thereby reducing the size of the equipment and rotating the tube. The moving speed can be increased, and the processing time until a desired unequal thickness tube is formed is shortened.

[0033] Further, the present invention provides a method of manufacturing a wheel rim for a vehicle, wherein a pressing projection that rotates a cylindrical element tube loosely fitted to a mandrel roll to form a pressing width that gradually widens in the arrangement order. A plurality of pressing rolls each having a circumference are sequentially moved to a position where each pressing protrusion presses against the cylindrical element tube according to the order, and while the cylindrical element tube rotates at least once. By pressing and maintaining the pressing protrusion against the cylindrical element tube, and repeating the movement and pressing maintenance of each pressing roll, the thin peripheral portion is formed so as to gradually widen in steps, thereby forming a thin peripheral portion having a predetermined width. Therefore, a wheel rim having an unequal thickness shape is formed by partially thinning a predetermined part having a sufficient strength. Can be manufactured. Furthermore, in the wheel rim forming method, the basic unit of the material can be reduced, so that the weight of the rim can be reduced and the manufacturing cost can be kept low. In addition, since the unequal thickness tube can be formed in a relatively short time, the unequal thickness shape is maintained while sufficiently maintaining the productivity of a normal wheel rim. It is possible to obtain a wheel rim.

[0034] Further, the unequal thick tube forming apparatus of the present invention is a roll revolving member that supports a pressing roll group having a plurality of pressing roll forces as well as loosely fitting and rotating a cylindrical element tube on a mandrel roll. In accordance with a permutation in which the pressing widths of the pressing protrusions of the pressing rolls are sequentially expanded, each pressing position is pressed between the mandrel roll and the pressing support roll on which the roll revolving member is externally pressed against the cylindrical element tube. By rotating the pressing rolls so that the positions of the pressing rolls are sequentially changed, the pressing protrusions of the pressing rolls are sequentially pressed so that the width of the pressing rolls is gradually increased until a thin peripheral portion with a predetermined width is obtained. Since the cylindrical element pipe is formed into a desired unequal-thickness pipe, it has a thin-walled peripheral portion with a predetermined width without substantially changing the inner diameter of the cylindrical element pipe. And the tube length is lengthened It is possible to form the unequal meat Atsukan of Nozomi. The unequal thick tube forming apparatus of the present invention can be formed with a relatively small pressing force, and the apparatus itself can be miniaturized, and at the same time, the desired unequal thick tube can be formed in a short time. It is possible to demonstrate the nature. Therefore, since it can be easily and properly disposed on the rim production line of a vehicle wheel, an unequal thickness rim obtained by thinning a predetermined portion having a sufficient strength is replaced with a rim having a substantially uniform thickness. Molding can be performed with almost the same productivity as the normal molding. Also, in the rim production line, unequal thick pipes can be formed after the trimming process, so that the cylindrical pipes can be welded and trimmed properly, and the welded part is smooth. It can be formed into a property. Furthermore, if the tube length of the cylindrical tube is designed in advance, it is possible to form an unequal-thickness rim with a desired length of the cylindrical tube force with a short tube length. Units can be reduced, and material costs and rim weight can be reduced.

[0035] In such an unequal thick tube forming apparatus, the axial position of the cylindrical element tube loosely fitted to the mandrel roll is determined, and the axial direction of the cylindrical element tube generated by the pressing process of the pressing roll is determined. In the case of a configuration provided with positioning means that does not hinder the stretching deformation of the tube, the positioning means can reliably form a thin peripheral portion at a desired axial position and lengthen the pipe length. The stretching deformation to be performed is appropriately performed. Thus, excellent productivity can be maintained when applied to the rim production line.

[0036] Further, in the above-described unequal thick tube forming apparatus, a mandrel roll and a pressure support roll Are converted into a separation position where the cylindrical element tube can be inserted and removed and a processing position where the cylindrical element pipe loosely fitted to the mandrel roll can be pressed by the pressing roll at the pressing position. In the case of the configuration provided with the conversion means, it is possible to easily fit the cylindrical element tube into the mandrel roll and to remove the unequal-thickness tube from the mandrel roll after pressing. Thus, a series of processes for forming unequal thick-walled tubes proceeds smoothly, and high productivity can be maintained.

[0037] Further, in the unequal thick-walled tube forming apparatus described above, the cylindrical element tube is disposed on both sides of the pressing position where the cylindrical element tube and the pressing roll are clamped by the mandrel roll and the pressing support roll. When the structure is equipped with a tube presser roll that presses against the roll, the inner peripheral surface of the cylindrical element tube can be sufficiently supported by the mandrel roll at the pressing position, thus preventing deformation of the inner side of the element tube. Can do. Further, even during the pressing process, the cylindrical tube can be rotated while maintaining a predetermined rotation speed, and high productivity can be stably maintained.

[0038] Further, in the unequal thick-walled tube forming apparatus described above, the pressing protrusions of the pressing roll are provided with inclined peripheral surfaces that are inclined so as to be flared on both sides thereof. In such a case, the thin peripheral portions can be formed sequentially and properly without causing problems such as covering deformation by the pressing process executed one after another. Thus, even when the cylindrical tube is arranged at a high speed and is rotated at a high speed, pressing by each pressing roll is smoothly performed, and high production stability can be exhibited.

[0039] On the other hand, in the unequal thick-walled tube forming apparatus described above, the roll revolving member aligns each pressing roll with one end of each pressing protrusion, and the pressing width expands to the other side. When it is arranged around the pressing support roll, it is stretched and deformed to the other side by pressing. As a result, the position of the thin peripheral portion as the unequal-thickness tube can be designed relatively easily, and the cylindrical element tube can be easily positioned in the axial direction with respect to the pressing position.

[0040] Alternatively, when the roll revolving member is arranged around the pressing support roll so that the pressing width of each pressing protrusion expands to both sides, the pressing roll is subjected to pressing processing. It will be stretched and deformed in both axial directions. In this pressing process, the processing widths that widen on both sides of the thin-walled peripheral part contribute to stretching deformation on both sides, respectively. The processing width on one side can be reduced with respect to the stretching length. Therefore, it is suitable for reducing the number of pressing rolls or rotating the cylindrical element tube at a higher speed. Further, it can be suitably used when molding a thin peripheral portion having a relatively wide width. Brief Description of Drawings

FIG. 1 is a conceptual diagram viewed from the front of an unequal thick-walled tube forming apparatus 1 according to the present embodiment.

FIG. 2 is a conceptual diagram viewed from the side of the unequal thick-walled tube forming apparatus 1 of the present embodiment.

FIG. 3 is an explanatory diagram showing a state in which the pressing force is sequentially applied by the six pressing rolls 20a to 20f of the present embodiment to form thin peripheral portions yl to y6.

FIG. 4 is an explanatory view showing a state in which the mandrel roll 2 is located at (A) a separation position H2 where the cylindrical element tube X is loosely fitted and (B) a machining position HI where the pressing force can be pressed.

FIG. 5 is a conceptual diagram of a side view of an apparatus in which a group of pressing rolls having other configurations (pressing rolls 70a to 70f) is provided.

FIG. 6 is an explanatory view showing a state in which thin peripheral portions yl to y6 are formed by sequentially pressing with pressing rolls 70a to 70f.

FIG. 7 is a conceptual view of a device in which a group of pressing rolls having another configuration (pressing rolls 80a to 80e, flat roll 81) is disposed as viewed from the front.

[FIG. 8] An explanation showing a state in which a thin jet yl l, yl 2 to a thin peripheral part y41, y42 and a thin peripheral part y51 are formed by pressing the pressure by a pressing roll 80a to 80e and a flat roll 81 FIG.

FIG. 9 is a chart showing the results of measuring the tube length for each pressing force by the pressing rolls 80a to 80e.

FIG. 10 is a cross-sectional view showing the shape of a wheel rim 90 that is produced by incorporating the unequal thick-walled tube forming apparatus 1 of this embodiment into a rim production line.

Explanation of symbols

[0042] 1 Unequal wall thickness pipe forming device

2 Mandore no Ronore

3 Press support roll

15 Roll revolving member

20a ~ 20f pressing roll 21 Roll outer peripheral surface

22a-22f Pressing protrusion

23 Inclined circumferential surface

35 Tube presser roll

90 wheel rim

T circumference width

tl to t6 Pressing width

Y Thin circumference

yl ~ y6 Thin wall circumference

X Unequal thickness tube

X Cylindrical tube

BEST MODE FOR CARRYING OUT THE INVENTION

Embodiments according to the present invention will be described in detail with reference to the accompanying drawings.

1 and 2 are conceptual diagrams showing an unequal thick-walled tube forming apparatus 1 according to the present invention, in which FIG. 1 is a front view and FIG. 2 is a side view. The unequal thick-walled tube forming apparatus 1 includes a mandrel roll 2 for loosely fitting a cylindrical element tube X, and a press support roll 3 having a plurality of press rolls 20a to 20f arranged around each. The central axes are provided so as to be substantially parallel. Here, in this embodiment, six pressing rolls 20a to 20f are arranged around the pressing support roll 3, and these pressing rolls 20a to 20f are the pressing rolls that exert power on the present invention. Groups (not shown) are organized. In addition, description and description in the drawings are omitted for the frame that supports each roll, the rotation shaft of each roll, the bearing that supports the drive shaft, and the like.

[0044] A drive shaft 10 is connected to the mandrel roll 2 along the central axis. The drive motor 12 that rotates the drive shaft 10 causes the mandrel roll 2 to be centered on the central axis. It is designed to rotate along the circumferential direction. The drive of the drive motor 12 is controlled by a control device (not shown). In this embodiment, the mandrel roll 2 has an outer diameter slightly smaller than the inner diameter of the cylindrical element tube X, and the cylindrical element tube X is loosely fitted. The unequal thick tube X after molding is easily removed and obtained. In addition, a drive shaft 11 protruding in the front-rear direction along the central axis is connected to the above-described press support roll 3, and the press support is supported by a drive motor 13 that rotates the drive shaft 11. The roll 3 rotates around the central axis along the circumferential direction. The drive of the drive motor 13 is controlled by a control device (not shown). Further, the pressing support roll 3 is provided with contact peripheral surfaces 4 and 4 around which the outer peripheral surfaces 21 of the press rolls 20a to 20f are circumferentially provided on both outer sides in the axial direction, and escapes between the contact peripheral surfaces 4 and 4. Groove 5 is formed!

[0046] For each of the press rolls 20a to 20f disposed around the press support roll 3, an outer force is also pressed to the cylindrical outer tube X loosely fitted to the mandrel roll 2 on the outer peripheral surface 21 of each roll. Pressing protrusions 22a to 22f are formed. When the pressing protrusions 22a to 22f are pressed by the cylindrical element tube X (see FIG. 3), the axial widths of the pressing protrusions 22a to 22f (hereinafter referred to as pressing elements) are applied to the cylindrical element tube X. Width) Form a thin peripheral part yl to y6 (see Fig. 3) according to tl to t6. Here, in this embodiment, six pressing rolls 20a to 20f are arranged, which will be described in detail later.

[0047] The six pressing rolls 20a to 20f are arranged by the roll revolving member 15 around the pressing support roll 3 so as to be substantially evenly spaced in the circumferential direction. Here, the roll revolving member 15 is composed of a front and rear annular member (not shown) whose inner peripheral edge is supported by the drive shaft 11 so as to be free to rotate, and each of the pressing rolls 20a to 20f is allowed to play freely from both the front and rear sides. It is provided to support the roll. Note that the annular bodies on both the front and rear sides are connected by a joining member (not shown). The roll revolving member 15 allows each of the pressing rolls 20a to 20f to freely rotate from both the front and rear rotating shafts 25m and 25η projecting from the front and rear thereof, and also presses the outer peripheral surface 21 of each roll. It is supported so as to be in contact with the contact peripheral surfaces 4 and 4 of 3. Here, the pressing protrusions 22a to 22f of the pressing rolls 20a to 20f are inserted into the escape grooves 5 of the pressing support roll 3 and are not in contact with the pressing support roll 3.

Furthermore, as shown in FIG. 2, each pressing roll 20a to 20f is provided with a front rotating shaft 25m so as to protrude forward from the roll revolving member 15, and the rotating shaft 25m A rotating gear 18 for rotation is arranged on the shaft. Further, as described above, the drive shaft 11 of the press support roll 3 is also provided so as to protrude forward from the press support roll 3, and the drive shaft 1 A rotating gear 19 for rotation is disposed at a front projecting portion of 1. Then, the rotation gear 18 for rotation and the rotation gear 19 for rotation rotate together to transmit the rotation of the drive shaft 11 to the rotation shaft 25m. That is, the rotation of the drive motor 13 is transmitted to the pressing rolls 20a to 20f by the rotation gear 18 for rotation and the rotation gear 19 for rotation. Here, the rotational gear 18 for rotation is set so that its pitch circle diameter is equal to the outer diameter of the pressure rolls 20a to 20f, and the rotational gear 19 for rotation is supported by its pitch circle diameter. It is set to be equal to the outer diameter of roll 3. Thus, the pressing rolls 20a to 20f are rotated at the same peripheral speed as that of the pressing support roll 3. Note that the rotation gear 18 for rotation and the rotation gear 19 for rotation are omitted in FIG. 1 (and FIG. 4).

In the roll revolving member 15 described above, a revolving geared portion 27 is formed around the drive shaft 11 at the rear portion of the rear member. The revolving geared portion 27 is supported around the drive shaft 11 so as to be freely rotatable. A revolving gear 17 that is rotated by the stepping motor 16 is disposed so as to mesh with the revolving geared portion 27. By controlling the driving of the stepping motor 16, the roll revolving member 15 rotates around the drive shaft 11, and according to this, all the pressing rolls 20a to 2 Of are integrally revolved. That is, the roll revolving member 15 revolves all of the pressing rolls 20a to 20f integrally, and enables the individual pressing rolls 20a to 20f to rotate. The stepping motor 16 is connected to a control device (not shown) and is controlled at a predetermined rotational speed. Here, the rotation drive member 17, the stepping motor 16, the control device, and the like constitute the rotation drive control means of the present invention. In this way, the roll revolving member 15 integrally revolves the six pressing rolls 20a to 20f, and is similar to a cage in a planetary mill.

[0050] As described above, the pressing rolls 20a to 20f are formed between the pressing support roll 3 and the mandrel roll 2, and the pressing protrusions 22a to 22f are loosely fitted to the mandrel roll 2. The roll revolving member 15 is moved to a position where it is in pressure contact with the tube X by being driven in a circular motion. And the press protrusions 22a-22f of the press rolls 20a-20f are cylindrical. At the position where they are pressed against the raw tube x, both of them are sandwiched between the pressing support roll 3 and the mandrel roll 2, and the pressing protrusions 22a to 22f connect the cylindrical raw tube X from the outside. Press. This position is the position where the pinching pressure becomes the largest, that is, the position force pressing position P that is pressed most deeply by the pressing protrusions 22a to 22f. In this way, the roll revolving member 15 rotates around the pressing support roll 3 and sequentially converts the pressing rolls 20a to 20f to the pressing position P, whereby the pressing roll positioned at the pressing position P is obtained. 20a to 20f press the cylindrical element tube X by the pressing protrusions 22a to 22f to form thin-walled peripheral parts yl to y6 (see FIG. 3). Here, the roll revolving member 15 is controlled by the stepping motor 16 so that the pressing rolls 20a to 20f are stopped at the pressing position P while the cylindrical element tube X is rotated at least once. In this embodiment, each of the pressing rolls 20a to 20f is stopped at the pressing position P while the cylindrical tube X is rotated twice.

[0051] Further, the mandrel roll 2 is connected to a position change control device 30 that moves the mandrel roll 2 in the vertical direction (FIG. 1). Then, by this position conversion control device 30, the mandrel roll 2 causes the pressing position 20 HI to press the pressing rolls 20 a to 20 f and the cylindrical tube X at the pressing position P together with the pressing support roll 3, and the pressing position. Separated from the support roll 3, the cylindrical element tube X is loosely fitted, and the position is changed to the separation position H2 where the unequal thick-walled tube X is removed (see FIG. 4). Here, the position conversion control device 30 includes a stepping motor 32 and a moving support rod 31 connected to the stepping motor 32, and the vertical length of the moving support rod 31 is a predetermined angle in the vertical direction with the length of the rod as a turning radius. It is controlled to reciprocate. Then, the mandrel roll 2 is connected to the moving support rod 31 so as to reciprocate between the processing position HI and the separation position H2. This position conversion control device 30 constitutes the position conversion means of the present invention.

[0052] In the present embodiment, the position of the pressing support roll 3 described above is fixed, and the mandrel roll 2 is changed in position as described above.

[0053] Further, in this unequal thick-walled tube forming apparatus 1, the cylindrical tube X loosely fitted to the mandrel roll 2 is pressed against the mandrel roll 2 on both sides in the circumferential direction of the pressing position P described above. There are pipe presser rolls 35 and 35 (Fig. 1). These pipe presser rolls 35, 35 are connected to the presser position (Fig. 4 (B)) and the presser position where the cylindrical element pipe X is pressed by an external force by means of a V, position changer (not shown). The position is converted to the retracted position (Fig. 4 (A)) away from the roll 2! Then, when the mandrel roll 2 with the cylindrical element tube X loosely fitted is located at the above-mentioned processing position, the tube retainer rolls 35, 35 press the cylindrical element tube X at the retainer position, When the thick tube X is formed, position conversion control is performed so that the thick tube X is located at a retracted position away from the unequal thick tube X. That is, the pipe presser rolls 35 and 35 are controlled to perform a position conversion operation in conjunction with the position conversion control device 30 that converts the position of the mandrel roll 2.

[0054] Next, the above-described pressing rolls 20a to 20f will be described in detail.

The six pressing rolls 20a to 20f constituting the pressing roll group constitute a desired unequal thick tube X by sequentially pressing the pressing protrusions 22a to 22f at the pressing position P as shown in FIG. Each of the thin peripheral portions yl to y6 is formed so as to gradually increase in steps up to a predetermined width (hereinafter referred to as the peripheral portion width) T of the thin peripheral portion Y. Here, the pressing protrusion 22a~22f so as to form a thin peripheral portion yl~ _y 6 sequentially expanding width, the pressing width tl~t6 is respectively set! Ruヽ. That is, in this embodiment, since six pressing rolls 20a to 20f are arranged, from the pressing roll 20a in which the pressing protrusion 22a having the narrowest pressing width tl is formed, The thin circumferential portion Y is formed in six stages by sequentially pressing the pressing roll 20f around which the pressing protrusion 22f having the widest pressing width t6 is formed. The thin peripheral portion y6 formed by the pressing roll 20f of the widest pressing protrusion 22f becomes the thin peripheral portion Y having the peripheral width T.

[0055] Here, each pressing roll 20a to 20f has an integrated area (processing area) of the axial processing dimension (processing width) and the circumferential contact length in which the respective pressing protrusions 22a to 22f are sequentially expanded. It is supposed to work on the pressure port. That is, the pressing protrusion 22a of the pressing roll 20a presses a region where the pressing width t1 and the circumferential length are integrated. Further, the pressing protrusion 22b of the pressing roll 20b performs a pressing process on a region obtained by adding the circumference to the difference width between the pressing width t2 and the pressing width tl of the pressing roll 20a. Similarly, the pressing protrusion 22c of the pressing roll 20c presses a region obtained by adding the circumference to the difference width between the pressing width t3 and the pressing width t2 of the pressing roll 20b. Even if the pressing rolls 20d to 20f after that are pressed, the pressing process is similarly performed.

[0056] The pressing protrusions 22a to 22f include inclined peripheral surfaces 23 and 23 that have hems spread on both sides in the axial direction, and the inclined protrusions 22a to 22f. Between the inclined circumferential surfaces 23, 23, circumferential surfaces 24a to 24f substantially parallel to the roll outer circumferential surface 21 and force are also formed. In the present embodiment, the inclined peripheral surfaces 23 and 23 have the same inclination angle in all the pressing protrusions 22a to 22f, and are formed at an inclination angle of about 30 degrees with respect to the roll outer peripheral surface 21. In addition, since each pressing protrusion 22a-22f is comprised by the same inclination surrounding surface 23, 23, the axial direction width | variety of the surrounding surfaces 24a-24f will differ according to the pressing width tl-t6. .

[0057] Further, the pressing protrusions 22a to 22f are provided so that the distances protruding radially outward from the roll outer peripheral surface 21 are the same. In addition, the outer diameter of each roll outer peripheral surface 21 of each pressing roll 20a-20f is also made the same. Thereby, each press roll 20a-20f forms each thin-walled peripheral part yl-y6 in substantially the same thickness. The protruding heights of the pressing protrusions 22a to 22f are set so that the thin peripheral portion Y of the unequal thickness tube X has a desired thickness.

[0058] Here, when the pressing rolls 20a to 20f are located at the pressing position P described above, the outer peripheral surface 21 of the roll does not generate a pinching force between the cylindrical raw tube X and the pressing rolls 20a to 20f. It is designed to be close to the outer peripheral surface of the cylindrical tube X. That is, the roll outer peripheral surface 21 may be slightly separated or may be substantially in contact. Thus, in the processing position HI of the mandrel roll 2 described above, the distance between the mandrel roll 2 and the press support roll 3 is the sum of the thickness of the cylindrical tube X and the outer diameter of the press rolls 20a to 20f. It is set to be approximately equal to the distance. As a result, when the pressing rolls 20a to 20f perform the pressing force at the pressing position P, the expansion that occurs in the thickness direction can be prevented. In addition, by preventing the stretching in the thickness direction as described above, the effect of stretching in the axial direction is greatly generated.

[0059] Then, such six pressing rolls 20a to 20f are arranged at substantially equal intervals around the pressing support roll 3 by a roll revolving member 15 fitted on the pressing support roll 3 as shown in FIG. Arranged. Here, on the roll revolving member 15, six pressing rolls 20a to 20f are arranged in the order of gradually widening the pressing protrusions 22a to 22f. In this embodiment, the pressing rolls 20a to 20f are arranged in order in the clockwise direction on the paper surface of FIG.

Here, in this embodiment, as shown in FIG. 3, the six pressing rolls 20a to 20f are connected to the respective pressing protrusions 22a to 22f at one end portion (in the drawing). The axial position of the right end is equal It is supposed to be organized so that it becomes better. Then, on the roll revolving member 15, the pressing protrusions 22a to 22f are arranged so as to sequentially expand to the other side from the pressing roll 20a with the narrowest pressing pressure width tl to the pressing roll 20f with the pressing width t6. . By pressing the six pressing rolls 20a to 20f and pressing widths tl to t6 in order, the thin peripheral portions yl to y6 are formed so as to widen to one side in the axial direction. It becomes.

[0061] On the other hand, when the cylindrical element tube X is loosely fitted to the mandrel roll 2, the insertion side end of the cylindrical element tube X abuts, so that the axial position of the cylindrical element tube X is in contact with it. The flange part 6 is positioned around (Figs. 2 and 3). The axial position of the flange portion 6 and the pressing protrusions 22a to 22f of the pressing rolls 20a to 20f described above determines the axial position of the thin circumferential portion Y formed on the cylindrical element tube x. . And the roll revolving member 15 arrange | positions each press roll 20a-20f so that the one side edge part of each press protrusion 22a-22f may become the same on the same side as the flange part 6 of the mandrel roll 2, respectively. ing. As a result, the stretching deformation that extends the tube length generated by the pressing process of the pressing rolls 20a to 20f can be caused to occur on the side opposite to the flange portion 6. Accordingly, it is possible to prevent stretching deformation from occurring on the flange portion 6 side and be prevented by the flange portion, and the axial positions of the pressing rolls 20a to 20f and the raw tube from being displaced.

[0062] It should be noted that the outer peripheral surface force of the mandrel roll 2 protrudes outward so that the flange portion 6 does not come into contact with the outer peripheral surface 21 of the pressing rolls 20a to 20f during pressing.

[0063] Next, regarding the case where the unequal thick tube forming apparatus 1 according to the present invention described above is applied to a rim production line for a two-piece type automobile wheel in which a wheel disc and a wheel rim are joined, This will be explained in accordance with the process of forming the unequal thickness tube X. Here, the unequal thickness tube forming apparatus 1 is disposed before the roll processing step for forming the rim shape, and the unequal thickness tube X formed from the cylindrical element X is transferred to the roll processing step. The production line is assembled in such a way.

Incidentally, in the wheel rim 90 molded in this embodiment, as shown in FIG. 10, flange portions 91, 92 are formed on both the front and back sides, and tire beads are formed on the flange portions 91, 92. The bead seats 93 and 94 on both sides are coupled to each other. A drop portion 97 is coupled from the bead sheet portion 93 on the front side through the well portion 95, and the back of the drop portion 97 is connected. On the side, a wedge portion 98 is formed through a well portion 96, and the wedge portion 98 is continuous with a bead sheet portion 94 on the back side. In this wheel rim 90, the ridge 98 and the back wel 96 between the back bead sheet portion 94 and the drop portion 97 are formed thinner than the other parts. The portion of the ridge portion 98 and the back side well portion 96 has a sufficient margin in strength of an automobile wheel having a large thickness when formed on a normal rim production line. In this embodiment, a wheel rim 90 having a thinned portion is formed, and the wheel for an automobile is generally made lighter.

[0065] Hereinafter, it will be described in detail according to the production process of the wheel rim 90.

First, a rectangular metal plate (not shown) having a substantially uniform plate thickness is prepared. In this metal plate, the plate thickness is set according to the wall thickness required for the portion of the wheel rim where the highest strength is required when it becomes an automobile wheel. The long side length of the metal plate is set according to a desired rim diameter. Further, the short side length is set in advance so as to be formed into a desired rim width after the wheel rim is formed. In this embodiment, the short side length of the metal plate is set in consideration of the stretch length that is stretched and deformed in the rim width direction (axial direction) by the processing step of the unequal thickness tube forming apparatus 1. Therefore, the short side length is shorter than in the case of a normal rim production line in which the unequal thick tube forming apparatus 1 is not provided. In other words, the basic unit of the metal plate is small.

[0067] The metal plate is bent almost uniformly so that the short sides on both sides are aligned, and is welded in a state where the short sides are in contact with each other, thereby forming a cylindrical body. Then, a trimming process is performed to cut the weld pile protruding inward and outward by this welding and the groove protruding to both sides. By this trimming process, the welded portion is made into a smooth curved surface, and the cylindrical element tube X according to the present invention is formed. Here, the cylindrical element tube X generally has a tube length shorter than its diameter. The tube length of the cylindrical element tube X indicates the rim width when the wheel rim is formed.

[0068] The above-described steps from preparing a metal plate having a predetermined dimension, welding, and performing trimming are the same as those performed on a normal rim production line, and details are omitted. .

[0069] The cylindrical element tube X formed in this way is transferred to the unequal-thickness tube forming apparatus 1, and a thin-walled peripheral portion Y is formed to become the unequal-thickness tube X. In this embodiment, as described above, molding The rear rim 90 is formed by thinning the ledge portion 98 and the back side well portion 96 so that these portions of the cylindrical tube X are formed by a subsequent roll processing step. Thin wall Y is formed. For this reason, as described above, the flange portion 6 of the mandrel roll 2 and the pressing protrusions of the pressing rolls 20a to 20f are formed so that the thin peripheral portion Y can be formed at the portion where the ledge portion 98 and the back side well portion 96 are formed. The axial positional relationship with the parts 22a to 22f is set.

[0070] It should be noted that in the unequal thick-walled tube forming apparatus 1, before the cylindrical element tube X is transferred, the mandrel roll 2 is in the separation position H2, and the tube presser rolls 35, 35 are in the retracted position. (See Fig. 4 (A)). At this time, the roll revolving member 15 has a pressing roll 20a around which the pressing protrusion 22a set to the narrowest pressing width tl is formed, and a pressing protrusion 22f set to the widest pressing width t6 around the periphery. It stops so that a pressing position P exists between the pressing roll 20f formed.

[0071] When the cylindrical raw tube X is transferred to the unequal thick-walled tube forming apparatus 1, as shown in Fig. 4 (A), the cylindrical raw tube X is idled to the mandrel roll 2 existing at the separation position H2. Fit. Here, the cylindrical element X is brought into contact with the flange portion 6 and its axial position is determined (see FIG. 2). Thereafter, the position conversion control device 30 is driven to move the mandrel roll 2 upward in a state in which the cylindrical raw tube X is loosely fitted, thereby converting the position from the separation position H2 to the processing position HI. Then, as shown in FIG. 4 (B), when the mandrel roll 2 is converted to the processing position HI, the pipe presser rolls 35, 35 are moved to the presser position, and the cylindrical element tube X is also applied with its outer force. Press against mandrel roll 2. As a result, the region between the two side tube pressing rolls 35, 35 of the cylindrical element tube X is in a state where the inner peripheral surface thereof is surface-supported by the outer peripheral surface of the mandrel roll 2. Further, the drive motor 12 to which the drive shaft 10 is connected is controlled to rotate the mandrel roll 2 at a predetermined peripheral speed. Similarly, the drive motor 13 to which the drive shaft 11 is connected is driven and controlled so that the pressing support roll 3 is rotated at a predetermined peripheral speed. By driving the drive motor 13, the pressing rolls 20a to 20f are also rotated at a predetermined peripheral speed in synchronization with the pressing support roll 3. Here, the mandrel roll 2 and the pressing support roll 3 are controlled to rotate in the same direction and the same peripheral speed. Further, the pressing rolls 20a to 20f rotate in the opposite direction at the same peripheral speed. In this embodiment, the mandrel roll 2 and the pressure support roll 3 are rotated clockwise on the drawing, The screws 20a to 20f are assumed to rotate counterclockwise.

[0072] As described above, when the mandrel roll 2 rotates, the cylindrical element tube X that is pressed against the mandrel roll 2 also rotates.

Then, the stepping motor 16 is driven to rotate the roll revolving member 15 along the pressing support roll 3 and move the pressing roll 20a to the pressing position P. Here, the roll revolving member 15 moves counterclockwise on the drawing. Then, when the pressing roll 20a reaches the pressing position P, the driving of the stepping motor 16 is stopped and the circumferential rotation of the roll revolving member 15 is stopped (see FIG. 1). At this pressing position P, the pressing roll 20a and the cylindrical element tube X are clamped by the mandrel roll 2 and the pressing support roll 3, and the pressing protrusion 22a of the pressing roll 20a holds the cylindrical element tube X in the pressing position P. The external force is also pressed. Then, by rotating the cylindrical element tube X according to the rotation of the mandrel roll 2, a thin peripheral part yl corresponding to the shape of the pressing protrusion 22a is formed over the outer periphery of the cylindrical element tube X. (Figure 3 (A)). Here, in this embodiment, the roll revolving member 15 is controlled in a state in which the circumferential rotation is stopped so that the pressing roll 20a is in the pressing position P while the mandrel roll 2 makes two turns. As a result, the pressing roll 20a can stably form the thin peripheral portion yl into an appropriate shape.

[0074] Furthermore, when the pressing protrusion 22a of the pressing roll 20a is pressed against the cylindrical element tube X, it is stretched and deformed in the axial direction along with the formation of the thin peripheral portion yl (not shown). Here, the pressing roll 20a is pressed in the circumferential direction of the cylindrical element tube X as the cylindrical element tube X rotates. The pressing width tl of the pressing protrusion 22a is one stage in which the circumferential width T is formed in six stages, and the processing width associated with the pressing process is extremely shorter than the tube length of the cylindrical element tube X. Becomes smaller. For this reason, in the axial direction, the pressing portion 22a is not pressed by the pressing projection 22a, and the processed portion to be pressed is sufficiently smaller than the non-processed portion. Therefore, due to this non-forced portion, stretching deformation in the circumferential direction that is the processing direction of the pressing protrusion 22a is constrained, and the inner diameter of the cylindrical element tube X can hardly be changed by the pressing processing. The material removed (thinned) by the formation of the thin-walled peripheral portion yl flows in the axial direction, causing the thin-walled peripheral portion yl to stretch in the axial direction, and the tube length of the cylindrical element tube X is extended. Note that this axial deformation does not define the axial position of the cylindrical tube X. Occurs on the opposite side of flange 6.

Here, the fact that the mandrel roll 2 is pressed against the mandrel roll 2 on both sides of the pressing position P also contributes to restraining the stretching deformation in the circumferential direction.

[0076] Further, as described above, the pressing roll 20a is configured such that the roll outer peripheral surface 21 is close to the outer peripheral surface of the cylindrical element tube X along the axial direction of the portion subjected to the pressing force. Therefore, the cylindrical element tube X is prevented from expanding and deforming in the thickness direction. As described above, this is also converted into a stretching deformation in the axial direction.

[0077] As described above, by pressing the pressing roll 20a, the thin peripheral portion yl is formed in the cylindrical raw tube x, and the length of the raw tube is stretched and deformed in the axial direction along with the formation of the thin peripheral portion yl. It becomes. The cylindrical element tube X has almost the same inner diameter and has a thin peripheral portion yl.

[0078] Further, when the pressing roll 20a presses the cylindrical element tube x, the pressing hole 20a rotates in the opposite direction to the cylindrical element tube X as described above. It is moving. In this manner, the pressing process proceeds by the pressing process while the pressing roll 20a and the cylindrical element tube X rotate in the opposite directions. Furthermore, although the pressing roll 20a and the pressing support roll 3 are in pressure contact with each other and a load is applied between them, the pressing roll 20a and the pressing support roll 3 rotate in the opposite direction at the same peripheral speed. This reduces the energy loss of pressure and contributes to the smooth progress of the pressing process.

[0079] As described above, when the pressing roll 20a is pressed at the pressing position P while the cylindrical tube x rotates twice, the stepping motor 16 is driven again to rotate the roll revolving member 15 counterclockwise. The next pressing roll 20b is moved to the pressing position P. Then, the pressing protrusion 22b of the pressing roll 20b is pressed, and the thin peripheral portion yl is widened to form the thin peripheral portion y2 (FIG. 3 (B)). Here, since the pressing protrusions 22a to 22f of the pressing rolls 20a to 2 Of are uniform on the flange 6 side as described above, the thin peripheral portion yl is flanged by the pressing roll 20b. Widened to the opposite side of the part 6, a thin peripheral part y2 is to be formed.

[0080] Here, before the pressing roll 20b is pressed, the thin peripheral portion yl formed by the pressing roll 20a spreads outward on both axial edges as shown in Fig. 3 (A). Inclined circumference z, z Is formed. For this reason, when the pressing protrusion 22b of the pressing roll 20b presses the thin peripheral portion yl, the inclined peripheral portion z on the widening side can be rolled in the axial direction according to the pressing. Therefore, the thin peripheral portion y2 is formed by the pressing force of the pressing roll 20b so that the inclined peripheral portion z of the thin peripheral portion yl is not covered and deformed (FIG. 3 (B)).

[0081] Further, due to the pressing force of the pressing roll 20b, as the thin peripheral portion y2 is formed, it is stretched and deformed along the axial direction to the side opposite to the flange portion 6, and the tube length is extended (illustrated). (Omitted). This is because, similarly to the above-described pressing roll 20a, the processing width of the pressing width t2 with respect to the pressing width tl is sufficiently smaller than the pipe length, so that the stretching deformation in the circumferential direction is restricted. In addition, since the thin peripheral portion y2 is formed so as to widen to the opposite side to the flange portion 6, it can be relatively easily stretched in the axial direction without being prevented from widening deformation by the flange portion 6. It is supposed to be.

[0082] Even in the pressing roll 20b, like the above-described pressing roll 20a, the cylindrical element tube x is stopped at the pressing position P and pressed while the cylindrical element tube x makes two turns. Part y2 can be formed properly and stably!

[0083] As described above, when the cylindrical raw tube X rotates twice in a state where the pressing roll 20b is held at the pressing position P, the roll revolving member 15 is rotated counterclockwise again, and the next pressing roll 20b is rotated. 20c is moved to pressing position P. Then, the pressing roll 20c is pressed at the pressing position P while the cylindrical element tube X rotates twice, thereby forming a further widened thin peripheral portion y3 (FIG. 3 (C)). This pressing process also extends and deforms in the axial direction to extend the tube length, as described above.

[0084] Further, the pressing roll 20d, the pressing roll 20e, and the pressing roll 20f are sequentially transferred to the pressing position P, and are pressed while the cylindrical element tube X rotates twice, similarly to the pressing rolls 20a to 20c described above. Process (not shown). By sequentially pressing in this way, the thin peripheral portion y4 (FIG. 3 (D)), the thin peripheral portion y5 (FIG. 3 (E)), and the thin peripheral portion y6 (FIG. 3 (F)) are formed in this order. At the same time, the pipe length is extended by being deformed in the axial direction for each processing. Then, by forming the thin peripheral portion y6 by the pressing roll 20f, the unequal thick tube X (FIG. 3 (F)) force forming in which the thin peripheral portion Y having the predetermined peripheral width T is formed. Will be. [0085] As described above, when the pressing process is sequentially performed and the thin peripheral portion y6 is formed by the pressing roll 20f having the widest pressing width t6, the roll revolving member 15 is separated from the pressing roll 20f and the pressing port. Rotate to stop so that the pressing position P is positioned between the rail 20a (see FIG. 4B). Furthermore, the pipe presser rolls 35 and 35 are converted into the presser position force retracted position. Thereafter, the position conversion control device 30 converts the position of the mandrel roll 2 from the carpentry position HI to the separation position H2 (see FIG. 4A), and the desired thin peripheral portion Y is formed from the mandrel roll 2. Unequal wall thickness tube X is removed. In this way, the process of forming the unequal thickness tube X from the cylindrical element tube X is completed.

[0086] It should be noted that in the unequal thick-walled tube forming apparatus 1 of the present embodiment, the roll revolving member 15 is arranged so that the stepping motor 16 is shifted so that the pressing rolls 20a to 20f are sequentially converted to the pressing position P. It is controlled so as to be driven indefinitely. That is, the roll revolving member 15 is driven to rotate when the pressing rolls 20a to 20f are transferred to the pressing position P, and operates to stop at the pressing position P while the cylindrical element tube X rotates twice.

[0087] On the other hand, the unequal thickness tube X formed by the unequal thickness tube forming apparatus 1 is transferred to a roll processing step for forming a wheel rim shape. In this roll processing process, a flare process that widens the openings on both sides of the unequal thick tube X, and a roll that forms a wheel rim shape by pinching from inside and outside while rotating a predetermined roll mold The process, the expanding process to adjust the roundness, etc. are executed sequentially. Here, in the roll process for forming the wheel rim shape, the roll described above is formed so that the ridge portion and the back portion of the well are formed in the thin-walled peripheral portion Y formed in the unequal thick-walled tube X. Machining by mold is executed. Then, a desired wheel rim 90 in which the ridge portion and the back side well portion are thinner than other portions is formed by such a roll-caching process (FIG. 10). The roll caloe process is the same as the process performed on the normal rim production line, and details are omitted.

[0088] As described above, the unequal thick tube forming apparatus 1 according to the present invention can be incorporated in a normal rim production line and produce a desired wheel rim 90. That is, the same process as that of a normal production line may be used except that the number of steps for forming the unequal thickness tube X by the unequal thickness tube forming apparatus 1 is increased. Therefore, the time required to produce the wheel rim 90 is The time required for the forming process by the thick tube forming apparatus 1 only increases from the normal rim production time.

[0089] Here, as described above, the unequal thick-walled tube forming apparatus 1 is configured to press each of the pressing rolls 20a to 2 Of into a predetermined circumferential width T in six stages, In each pressing process, the processing area (the processing width X contact length in the circumferential direction) in which the pressing protrusions 22a to 22f are pressed by contact with the raw tube X is getting smaller. For this reason, in each pressing process by the pressing rolls 20a to 20f, the pressing process force required for the pressing process may be relatively small. And since this pressing force is small, the load applied to the molding apparatus 1 and the raw tube X is also relatively small. Therefore, the molding apparatus 1 is relatively small and can be easily and appropriately incorporated into the rim production line.

[0090] Furthermore, by incorporating this unequal thickness tube forming apparatus 1, the time required for the production of the wheel rim 90 is required for the molding process by the unequal thickness tube forming apparatus 1 in the normal rim production time. Time will increase. The forming time of the unequal thick-walled tube forming device 1 is determined by increasing the peripheral speed of the mandrel roll 2 for rotating the cylindrical tube X and the peripheral speed of the pressing support roll 3 so that each pressing roll 20a ~ It is possible to shorten the pressing time by 20f and shorten it. As described above, the unequal thick-walled tube forming apparatus 1 has a relatively small pressing force and a small load on the apparatus 1 and the raw tube X. Therefore, the mandrel roll 2 and the pressing support roll 3 described above. Even if the peripheral speed is increased, the thin peripheral part yl to y6 can be formed smoothly and appropriately. In other words, the unequal thick-walled tube forming apparatus 1 according to the present invention requires a relatively short processing time, and the rim production line force is only slightly increased. This means that the total time required for rim production is significantly reduced as compared to the case where a cutting process and a flow turning process are incorporated as in the conventional configuration described above.

Thus, the unequal thick-walled tube forming apparatus 1 according to the present invention is incorporated into a production line for producing a wheel rim 90 in which a portion having no influence on strength is partially thinned. Unprecedented high productivity can be exhibited. In addition, the unequal thick tube X formed by the forceful unequal thick tube forming apparatus 1 has an elongated tube length as described above. Because the basic unit of the metal plate forming tube X can be reduced Thus, it is possible to reduce the material cost and reduce the rim weight.

Next, another configuration for forming a similar unequal thickness tube X in the unequal thickness tube forming apparatus 1 described above will be described.

[0093] For example, as another configuration, as shown in FIG. 6, each of the pressing protrusions 72a to 72f has six pressing rolls 70a to 70f, and the pressing widths tl to t6 are sequentially expanded to both sides in the axial direction. It shall be provided around. Here, the pressing protrusions 72a to 72f are made to have the same processing width on both sides in the axial direction so that their center positions in the axial direction are aligned. The six pressing rolls 70a to 70f are arranged on the roll revolving member 15 so that the center positions of the pressing protrusions 72a to 72f are substantially the same in the axial direction (see FIG. 5). These six pressing rolls 70a to 70f constitute a pressing roll group (not shown)!

[0094] Further, as a positioning means for positioning the cylindrical element tube X in which the mandrel roll 71 is loosely fitted, the initial position of the cylindrical element tube X is determined, and the axial direction is determined by pressing with the pressing rollers 70a to 70f. Guide device that prevents stretching deformation that extends the pipe length to both sides 76 force It is arranged directly under the mandrel roll 71 (see Fig. 5). In this guide device 76, two guide rolls 77, 77 having a rotation axis in the vertical direction are juxtaposed along the axial direction of the mandrel roll 71 and are urged toward each other. Yes. The initial interval between the guide rolls 77 and 77 is set equal to the tube length of the cylindrical element tube X. By arranging the cylindrical element tube X, the thin peripheral portion Y can be formed at a predetermined position. In addition, the initial position of the cylindrical tube X with respect to the six pressing rolls 70a to 70f is determined. When the deformation of the pressing rolls 70a to 70f causes stretching deformation on both sides in the axial direction, the guide rolls 77 and 77 on both sides move outward against the urging force. The two guide rolls 77 and 77 are rotatably supported, and rotate according to the rotation of the cylindrical element tube X. The mandrel roll 71 is not formed with the flange portion 6 described above.

[0095] Even in such a configuration, similarly to the above, the six pressing rolls 70a to 70f are sequentially converted to the pressing position P so that the pressing widths tl to t6 are sequentially expanded, and FIG. As shown in (A) to (He), thin-walled peripheries yl to y6 are formed in order. Then, a thin peripheral portion Y having a predetermined peripheral width T is formed to obtain an unequal thickness tube X (see FIG. 6 (F)). Here, by pressing with six pressing rolls Is formed so that the thin-walled peripheral portions yl to y6 gradually widen to both sides in the axial direction. As a result, as the thin peripheral part yl to y6 is formed by the pressing process, the pipe is stretched and deformed so as to extend to both sides. By setting the tube length of the cylindrical element tube X in consideration of the stretched dimension of the tube length due to this stretching deformation, the basic unit of the material can be reduced.

[0096] Even with the strong configuration, the same wheel rim 90 can be properly produced and can exhibit the same effects as described above, similarly to the above. The press rolls 20a to 20f described above are provided except that the press protrusions 72a to 72f of the six press rolls 70a to 70f include different press roll groups and the guide device 76 is provided. The configuration is the same as the configuration, and the description thereof is omitted.

On the other hand, as yet another configuration, as shown in FIG. 8, four pressing rolls 80a to 80d each having two pressing protrusions 82a, 83a to 82d and 83d are formed, A pressing roll 80e (same as 20f) having a pressing protrusion 82e having a pressing width t6 equal to the circumferential width T of the roller, and a flat roll 81 including a roll outer peripheral surface 87 having no pressing protrusion. A pressing roll group (not shown) is provided. Here, the roll outer peripheral surface 87 of the flat roll 81 has the same outer diameter as the roll outer peripheral surface 21 of the other pressing rolls 80a to 80e. Then, a total of six various roll forces are arranged on the roll revolving member 15 at substantially equal intervals in accordance with the increased permutation of the pressing width as shown in FIG.

[0098] Note that, in the configuration including the pressing rolls 80a to 80e, as described later, as compared with the configuration including the pressing rolls 20a to 20f having the pressing protrusions 22a to 22f described above, It is possible to easily and properly form a thin peripheral portion with a wide peripheral width. Thus, in this embodiment, as shown in FIG. 8, the unequal thick tube X ′ in which the peripheral width T ′ of the desired thin peripheral portion Y ′ is wide is formed. The

Here, the pressing protrusions 82a and 83a to the pressing protrusions 82d and 83d of the pressing rolls 80a to 80d are set to pressing widths ti l, tl2 to pressing widths t41 and t42, and each pressing process is performed. According to the above, thin-walled peripheries yl l, yl2 to y41, y42 are sequentially formed. The pressing protrusion 82e of the pressing roll 80e is set to the pressing width t51, and the thin peripheral portion y41, y42 formed immediately before is connected to form the thin peripheral portion y51 by pressing. The pressing width t51 of the pressing protrusion 82e of the pressing roll 80e is equal to the circumferential width T ′, and is formed by the pressing roll 80e. The thin peripheral portion y51 becomes the desired thin peripheral portion Y ′.

[0100] Further, in the pressing rolls 80a to 80d, the peripheral surface between the two pressing protrusions 82a and 83a to the pressing protrusions 82d and 83d is compared with the outer diameter of the roll outer peripheral surface 21, respectively. The outer diameter is slightly smaller. This is tolerable to the expansion deformation in the thickness direction that occurs between the pressing protrusions 82a, 83a to the pressing protrusions 82d, 83d when the pressing force by the pressing rolls 80a to 80d is executed. It is for doing so. The above-described flat roll 81 is provided for the purpose of crushing the swelling in the thickness direction generated between the thin-walled circumferential edges y21 and y22 due to the pressing force Lo of the pressure inlets 80a and 80b.

[0101] In such a configuration, first, the pressing roll 80a that surrounds the two pressing protrusions 82a and 83a is pressed against the cylindrical element tube X as shown in FIG. Two thin-walled peripheries yl l and yl2 are formed simultaneously. After that, as shown in FIG. 8 (B), the pressing roll 80b that forms the next pressing protrusions 82b and 83b is pressed, and the two thin peripheral portions yl l and yl2 are expanded to reduce the thin peripheral portion. simultaneously forming a part _y 21, y22. Here, the space between the thin peripheral portions y21 and y22 is swelled inward and outward in the thickness direction, and the raw tube X in which the thin peripheral portions y21 and y22 are formed has a swelled portion at the mandrel roll. 71 is in contact. Next, as shown in FIG. 8C, the flat roll 81 is pressed to crush the swollen form formed between the thin peripheral portions y21 and y22.

[0102] Further, the pressing rolls 80c and 80d are sequentially pressed to form the thin peripheral portions y31 and y32 and the thin peripheral portions y41 and y42 as shown in FIGS. 8 (D) and 8 (E). Note that the pressure rolls of the pressing rolls 80c and 80d also cause bulges between the thin circumferential portions y31 and y32 and between the thin circumferential portions y41 and y42, but these bulges are crushed by the last small pressing roll 80e. It is.

[0103] After that, as shown in Fig. 8 (F), the thin-walled peripheral portion y51, which is formed by connecting the two thin-walled peripheral portions y41, y42 by the pressing roll 80e having one pressing protrusion 82e, is integrated. Form. In this way, an unequal thick tube X having a desired thin wall Y is formed.

[0104] Here, each of the pressing rolls 80a to 80d is provided with a shape in which two pressing protrusions are gradually widened to both sides in the axial direction. Produce. Further, since the pressing roll 80e is pressed so as to connect the two thin peripheral portions y41, y42, the pressing roll 80e is also deformed by stretching to both sides in the axial direction by the pressing. It will be. Therefore, even in this configuration, as described above, the mandrel roll 71 without the flange portion 6 and the guide device 76 are provided.

[0105] The four pressing rolls 80a to 80d having the two pressing protrusions formed in this configuration each have a pressing force to form two thin peripheral portions at the same time. It is. For this reason, for example, even when the desired thin circumferential portion Y ′ has a relatively wide circumferential width T ′, the processing of the individual pressing protrusions 82a and 83a to the pressing protrusions 82d and 83d is performed. The width can be set to be equal to or smaller than the processing width of the one-point pressing protrusions 22a to 22f described above. Accordingly, although the pressing force of the pressing rolls 80a to 80e is increased, the thin wall having a wide circumferential width T ′ is maintained while maintaining almost the same productivity as the configuration having one pressing protrusion. Circumference Y 'can be formed. The structure having the two pressing protrusions can appropriately form an unequal thick tube having a relatively wide thin peripheral portion Y ′, and can produce a wheel rim having a wide rim width. Can be suitably used. As shown in FIG. 8, in this configuration, the width is expanded to a relatively wide circumferential width T ′ by substantially five pressing rolls 80a to 80e.

[0106] When the circumferential width T is the same as the thin-walled circumferential portion Y formed by the one pressing projection 22a to 22f, the processing width of the pressing projection 22a to 22f is set. In comparison, the processing widths of the individual pressing protrusions 82a and 83a to the pressing protrusions 82d and 83d can be appropriately reduced to about half. If the cover width is small in this way, each pressing process can be performed more easily and appropriately, and further productivity can be improved.

In this configuration, the above-described pressing rolls 80a and 80b, flat roll 81, and pressing rolls 80c, 80d, and 80e are sequentially converted to the pressing position P, so that the thin peripheral portion is sequentially stepped as shown in FIG. The unequal thick-walled tube X having a thin circumferential portion Y ′ having a circumferential width T ′ is formed so as to widen in steps. As described above, the unequal-thickness tube X is obtained by extending the length of the cylindrical element tube X to both sides in the axial direction.

[0108] Even with the powerful configuration, it is possible to properly arrange the same wheel rim 90 by arranging it on the rim production line as described above, and to exhibit the same operational effects. The guide device includes four pressing rolls 80a to 80d having pressing protrusions in two places, a flat roll 81, and a pressing roll 80e having one pressing protrusion 82e. Except for the arrangement of 76, the configuration is the same as the configuration including the pressing rolls 20a to 20f described above. Omitted.

[0109] Next, the four pressing rolls 80a to 80d around which the two pressing protrusions described above are formed, the flat roll 81, and the one pressing roll 80e around which one pressing protrusion is formed. It was verified that the desired unequal-thickness tube X ′ was formed from the cylindrical element tube X by the configuration including the above.

[0110] Here, the cylindrical element tube X used in the test had a tube length of about 210 mm, a wall thickness of about 2.8 mm, and an outer peripheral length of about 1160 mm.

[0111] In addition, the desired unequal thick-walled tube X 'has a circumferential width T' of the thin circumferential portion Y 'of about 40 mm and a thickness of about 2. Omm.

[0112] The shapes of the pressing rolls 80a to 80e were set as follows. In addition, the inclination angle of the inclined peripheral surface of each pressing protrusion is about 30 degrees.

(1) The pressing roll 80a; the pressing width ti l of the pressing protrusion 82a is about 6 mm, the pressing width tl2 of the pressing protrusion 83a is about 6 mm, and the distance between the pressing protrusions 82a and 83a is about 21 mm.

(2) Press roll 80b; Pressing width t21 of pressing protrusion 82b is about 9 mm, pressing width t22 of pressing protrusion 83b is about l lmm, and the distance between pressing protrusions 82b and 83b is about 15 mm.

(3) Press roll 80c; Pressing width t31 of pressing protrusion 82c is about 12 mm, pressing width t32 of pressing protrusion 83c is about 16 mm, and the distance between pressing protrusions 82c and 83c is about 9 mm.

(4) Press roll 80d; Pressing width t41 of pressing protrusion 82d is about 15 mm, pressing width t42 of pressing protrusion 83d is about 21 mm, and the distance between pressing protrusions 82d and 83d is about 3 mm.

(5) Pressing roll 80e; The pressing width t51 of the pressing protrusion 82e is about 40 mm.

[0113] Further, the flat roll 81 has a roll outer peripheral surface 87 having the same outer diameter as the above-described outer peripheral surface 21 of the pressing rolls 80a to 80e.

[0114] In this verification process, every time pressing is performed by each of the pressing rolls 80a to 80e, the pipe length

(Axial length) is measured.

[0115] Then, the cylindrical raw tube X was sequentially pressed by the pressing rolls 80a to 80e to form an unequal thick tube X '(see Fig. 8). As a result of investigating the shape of this unequal-thickness tube X ', the thin peripheral portion Y' was about 39 mm wide and formed to a thickness of about 2. Omm. The tube length was about 222 mm, which was about 12 mm longer than the original cylindrical element tube X. Here, as a result of measuring the tube length for each pressing process as described above, it was gradually stretched and deformed as shown in FIG. . The stretch dimension in the axial direction for each stretch deformation is generated according to the work area that is the product of the work width and the perimeter of each press protrusion that widens the thin peripheral part for each press work, There is a certain correlation. As a result of examining this in detail, it was found that about 70% to 80% was used for stretching deformation with respect to the thinning amount of the thin peripheral portion formed one after another in each pressing process. In other words, it has become clear that the device of the present invention exhibits a high yield.

[0116] Thus, according to the unequal thick-walled tube forming apparatus of the present invention, a desired thin-walled peripheral portion Y 'is formed and the tube length is lengthened. Then, by using the thinning amount of the thin-walled peripheral part Y for lengthening the pipe length, the shape force of the thin-walled peripheral part Y ′ is also calculated in advance by calculating the extension length of the pipe length. The basic unit can be reduced. In particular, the apparatus of the present invention can exhibit a high yield, and by incorporating it into a normal rim production line, it is possible to increase the reduction range of the material basic unit and to reduce the weight of the rim.

[0117] Further, the peripheral speeds of the mandrel roll 71 and the pressure support roll 3 are controlled at a high speed, and the rotation of the roll support member 15 is controlled according to the peripheral speed so that the pressure rolls 80a to 80e are continuously provided. As a result of forming the unequal thick tube X ′ by pressing, the time required to form the unequal thick tube X ′ from the cylindrical raw tube X was about 10 seconds. In this way, because it is excellent in productivity for forming the unequal thick-walled tube X, as described above, even when incorporated in a normal rim production line, it is almost the same as the productivity of a substantially uniform wheel rim. High productivity.

[0118] From the above verification, the usefulness of the unequal thick-walled tube forming apparatus of the present invention was sufficiently proved.

[0119] As described above, in the unequal thick-walled tube forming apparatus 1 of the present embodiment, the force is configured such that the pressing force is sequentially applied by the six pressing rolls 20a to 20f. In addition, it is possible to perform pressing with five pressing rolls 80a to 80e. In addition, the number of pressing rolls can be variously set according to the desired peripheral width T. Further, in the above-described embodiment, the protruding heights of the pressing protrusions 22a to 22f from the outer peripheral surface 21 of the roll are made equal, but in addition, the protruding height is set so as to increase sequentially, It is also possible to make the depth of the thin-walled circumferential width yl to y6 gradually deeper for each pressing process.

[0120] In the above-described embodiment, the roll revolving member 15 is temporarily stopped at the pressing position P. In this way, the control is performed so as to intermittently drive around. By the way, each of the pressing rolls 20a to 20f only needs to be pressed and pressed so that the thin peripheral portion yl to y6 can be properly formed at the pressing position P, so that the pressing position P is rotated at a sufficiently low speed. Also good. In other words, the roll revolving member 15 is driven to rotate at a high speed until the pressure rolls 20a to 20f are moved to the place where the pressing force can be measured (pressing position P), and the cylindrical element tube X rotates twice. In the meantime, non-intermittent control is performed in which the peripheral speed is alternately converted into two stages so as to drive at low speed so that the pressing process is sufficiently performed.

[0121] Further, in the above-described embodiment, if the pressing force w by the pressing rolls 20a to 20f is controlled to be performed during at least one rotation of the cylindrical element tube X, the thin peripheral portion yl to y6 can be formed. Therefore, as described above, in addition to the configuration in which the cylindrical element tube X is controlled to be pressed while rotating twice, for example, the cylindrical element tube X is configured to be pressed while rotating three times or four times. You can also In this way, by increasing the number of rotations of the cylindrical tube X, each pressing process may be performed more sufficiently. It is also possible to set the cylindrical element tube X so as to be half a turn and half a turn.

[0122] Further, in the above-described embodiment, the pressing rolls 20a to 20f are configured to be rotated in the opposite directions at the same peripheral speed by the drive motor 13 that rotates the pressing support roll 3. However, as another configuration, the pressing rolls 20a to 20f may be disposed on the roll revolving member 15 so as to be freely rotatable. In this configuration, the pressing rolls 20a to 2Of are rotated by the sandwiching pressure between the pressing support roll 3 and the mandrel roll 2 when the cylindrical element tube X is pressed. Therefore, in order to execute the pressing process smoothly and stably, it is preferable to relatively increase the pressing force (load due to the pressing process) that generates the clamping pressure.

[0123] Also, in the above-described embodiment, the pressing protrusions 22a to 22f of the pressing rolls 20a to 20f are formed with inclined peripheral surfaces 23 and 23 having an inclination angle of about 30 degrees on both sides thereof. However, the inclination angle of the inclined peripheral surfaces 23 and 23 can be changed. Here, when the inclination angle is reduced, the circumferential planes 24a to 24f of the pressing protrusions 22a to 22f are narrowed, so that the lightening effect is reduced with the same circumferential width T. On the other hand, if the inclination angle becomes large and approaches 90 degrees, there is a concern that the cover deformation may occur due to the following pressing force as described above. From such a thing The inclination angle is preferably in the range of about 10 degrees to about 60 degrees.

[0124] Furthermore, in the above-described embodiment, the relief groove 5 is formed so that the pressing protrusions 22a to 22f of the pressing rolls 20a to 20f do not contact the pressing support roll 3. However, as another configuration, the groove depth of the escape groove 5 is set to be the same as the protrusion height of the pressing protrusions 22a to 22f, and the groove bottom surface of the escape groove 5 and the circumference of the pressing protrusions 22a to 22f are set. The flat surfaces 24a to 24f may be in contact with each other. Thereby, the press support roll 3 can support the load which acts on each press protrusion 22a-22f at the time of press processing still more directly.

[0125] In the unequal thick-walled tube forming apparatus of the present invention, other configurations that are not limited to the above-described embodiments can be appropriately changed within the scope of the gist of the present invention. For example, each pressing roll may have a plurality of pressing protrusions so as to form an unequal thick tube having a plurality of thin peripheral portions.

Claims

The scope of the claims

[1] The cylindrical element tube is loosely fitted to the mandrel roll, and the cylindrical element tube is rotated by the rotation of the mandrel roll, so that the pressing width is gradually increased in the arrangement order. A plurality of pressing rolls are sequentially moved in accordance with the order of the pressing protrusions configured to the respective pressing widths to a position where they are pressed against the cylindrical element tube, and the cylindrical element tube is rotated at least once. By pressing and maintaining the pressing protrusions of each pressing roll against the cylindrical element tube, and repeating the movement and pressing maintenance of each pressing roll, the thin peripheral portion is formed so as to gradually widen in a stepwise manner. A method for forming an unequal thick tube characterized by forming an unequal thick tube having a thin peripheral portion of width.

[2] The cylindrical element tube is loosely fitted to the mandrel roll, and the cylindrical element tube is rotated by the rotation of the mandrel roll, so that the pressing width is gradually increased in the arrangement order. A plurality of pressing rolls are sequentially moved in accordance with the order of the pressing protrusions configured to the respective pressing widths to a position where they are pressed against the cylindrical element tube, and the cylindrical element tube is rotated at least once. By pressing and maintaining the pressing protrusions of each pressing roll against the cylindrical element tube, and repeating the movement and pressing maintenance of each pressing roll, the thin peripheral portion is formed so as to gradually widen in a stepwise manner. A method for manufacturing a wheel rim for a vehicle, comprising: an unequal thick-walled tube forming step of forming an unequal thick-walled tube having a thin peripheral portion with a width.

[3] A mandrel roll in which a cylindrical element tube is loosely fitted and rotated by rotation thereof, and a pressing protrusion formed on the outer peripheral surface of the roll on the cylindrical element tube loosely fitted in the mandrel roll The outer force is sequentially pressed to form a plurality of pressing rolls that form a thin peripheral portion having a predetermined width on the raw tube, and the pressing protrusions of the pressing rolls are formed into a thin wall having a predetermined width in the arrangement order. A group of pressing holes set so that the pressing width is gradually increased until the circumferential portion is formed;

A roll revolving member that supports the pressing roll group so as to be rotatable in the circumferential direction by a permutation in which the pressing widths of the pressing protrusions of the pressing rolls sequentially expand, and enables the entire pressing roll to rotate integrally;

Provided substantially in parallel with the mandrel roll, a roll revolving member is fitted over and the outer peripheral surface of each press hole is in contact with the mandrel roll via the press roll. A pressing support roll for clamping the cylindrical element tube;

Each pressing roll is sequentially converted so that the pressing width is expanded to a pressing position where the pressing roll is pressed between the pressing support roll and the mandrel roll so that the pressing width is increased. A revolving drive control device for revolvingly driving the roll revolving member so that the pressing roll presses the cylindrical element tube at the pressing position;

An unequal thick-walled tube forming apparatus comprising:

[4] Positioning means that determines the axial position of the cylindrical element tube that is loosely fitted to the mandrel roll, and that does not hinder the axial deformation of the cylindrical element tube that is caused by pressing the pressing roll. The unequal thick-walled tube forming device according to claim 3, comprising:

[5] The mandrel roll and the pressing support roll are separated from each other by a position where the cylindrical element tube can be inserted and removed, and the cylindrical element tube loosely fitted to the mandrel roll is pressed by the pressing roll at the pressing position. 5. The unequal-thickness tube forming apparatus according to claim 3 or 4, further comprising position conversion means for converting into a process position to be enabled.

[6] The cylindrical element pipe and the pressing roll are clamped by the mandrel roll and the pressing support roll, and a pipe pressing roll for pressing the cylindrical element pipe against the mandrel roll is provided on both sides of the pressing position. The unequal thick-walled tube forming apparatus according to any one of claims 3 to 5.

[7] The pressing protrusion of the pressing roll is provided with an inclined peripheral surface that inclines so that the hems spread on both sides thereof, according to any one of claims 3 to 6. The unequal thick-walled tube forming device.

[8] The roll revolving member is configured such that each pressing roll is arranged around the pressing support roll so that one side end of each pressing protrusion is aligned and the pressing width is expanded to the other side. The unequal thick-walled tube forming apparatus according to any one of claims 3 to 7.

[9] The roll revolving member is characterized in that each pressing roll is arranged around the pressing support roll so that the pressing width of each pressing protrusion extends to both sides. The unequal thick-walled tube forming device according to any one of claims 3 to 8.