JPH0732072A - Manufacture of cylindrical article - Google Patents

Abstract

PURPOSE:To obtain a cylindrical article having beautiful appearance, which can easily manufacture even in the case of being a complicate shape. CONSTITUTION:In a method for manufacturing the cylindrical article by deforming to the radial direction of the cylindrical body forming plural lines of depressed grooves extended in the longitudinal direction depressed toward the center in the almost same interval on the outer peripheral surface of the cylindrical body 1, one or both processes in a diameter expanding process for expanding the diameter of the cylindrical body 1 by intensely pressing outerward from the inner peripheral surface of the cylindrical body 1 and/or a diameter contracting process for contracting the diameter of the cylindrical body 1 by intensely pressing innerward from the outer peripheral surface of the cylindrical body 1 are used. In the diameter expanding process, a diameter expanding member 31 having barrel part at larger than the inner diameter of the cylindrical body is pressed into the cylindrical body 1 from the opening part of the cylindrical body 1.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for manufacturing cups such as winning cups, cylindrical struts, and cylindrical articles such as various cylindrical decorative articles.

[0002]

2. Description of the Related Art Cylindrical metal tubular articles have been applied to various places in daily life such as a winning cup, a decorative stand of a desk lamp, or a staircase. Usually, such a tubular object has a strong decorative property, and a symmetrical curved surface is formed on the surface around the axial center when viewed from any lateral direction. Due to the strange combination of curved surfaces, the viewer has a pleasant aesthetic feeling. Will give you.

Such a cylindrical container is manufactured by various manufacturing methods. The simple ones are made by pressing one side on top of another and joining them together, and the abutting portions of each other are welded together. In addition, it may be manufactured by casting a complex shape into a mold.

However, in the case of the above press working, unevenness is formed on the welding surface, and in the case of the cast product, burrs are formed at the joined portion of the upper die and the lower die. Although the unevenness of the welded surface and the burr of the cast product are subjected to a treatment for removing them, the finished product still does not have a good appearance and a high-class feeling cannot be obtained. Because of that,
Conventionally, tubular articles that give a high-class feeling are often manufactured by forging.

[0005]

FIG. 15 exemplifies a prize cup such as a winning cup which is a forged product of a cylindrical container. As shown in FIG. 16, such a tubular forged product 10 uses a striking tool H such as a hammer so as to expand the diameter in the vicinity of the opening at one end of the tubular body 10a. Further, the hitting is performed so that the diameter is gradually reduced toward the central portion, and thereafter, the beating process in which the diameter expansion and the diameter reduction are combined is performed in each portion, and the forged product 10 as shown in FIG. 15 is completed. The hitting tool H may be a hand tool or a mechanical tool.

FIG. 17 shows a cross section of each part of the forged product 10 thus obtained. As shown in this figure, the wall thickness d1 in the vicinity of the opening 10b of the forged product 10 is thinner than the wall thickness d as a result of the tubular body 10a being stretched in the direction indicated by the white arrow, Part 10c
As a result of being reduced in diameter as indicated by a solid arrow, its wall thickness d2 is thicker than the wall thickness d of the cylindrical body 10a.

That is, in order to manufacture the forged products 10 having different diameters by forging, the operation of strongly hitting with the hitting tool H such as the hammer is performed on all outer peripheral surfaces along the longitudinal direction of the cylindrical body 10a. It has to be carried out, requires a great deal of labor and time, and has a drawback that it is not suitable for mass production.

The present invention has been made in order to solve the above-mentioned problems, and it is easy to manufacture even a complicated shape, and it is a seamless and beautiful appearance of a tubular container. It is intended to provide a way.

[0009]

According to the method of manufacturing a tubular instrument according to claim 1 of the present invention, a plurality of recessed grooves extending in the longitudinal direction which are recessed toward the center on the outer peripheral surface of the tubular body are substantially equal. A method for manufacturing a tubular article by radially deforming a tubular body formed at intervals, in which the tubular body is strongly pressed outward from the inner peripheral surface of the tubular body. One or both of a diameter expansion step of expanding the diameter and a diameter reduction step of reducing the diameter of the tubular body by inwardly pressing from the outer peripheral surface of the tubular body. Those who are characterized by using.

A method of manufacturing a tubular article according to a second aspect of the present invention is the method of manufacturing a tubular article according to the first aspect, wherein in the expanding step, the opening to the body portion of the tubular body are used. Is characterized in that a diameter-expanding member larger than the inner diameter of the tubular body is press-fitted into the tubular body.

The method for manufacturing a tubular article according to claim 3 of the present invention is the method for manufacturing a tubular article according to claim 1, wherein in the diameter reducing step, one side portion of the tubular body is straightened. It is characterized in that it faces the base end of the tapered constriction chamber of the mold and presses the other side of the cylindrical body to press the cylindrical body into the constriction chamber of the correction mold.

A method of manufacturing a tubular article according to claim 4 of the present invention is the method of manufacturing a tubular article according to claim 1, wherein a constriction strip is wound around the tubular body in the diameter reducing step. The characteristic feature is that the stenosis is narrowed.

A method for manufacturing a tubular article according to claim 5 of the present invention is the method for manufacturing a tubular article according to claim 1, wherein the outer peripheral surface of the tubular body is pressed in the diameter reducing step. It is characterized by that.

[0014]

According to the method of manufacturing a tubular article according to the first aspect, a plurality of recessed grooves extending in the longitudinal direction which are recessed toward the center are formed on the outer peripheral surface of the cylindrical body at substantially equal intervals. Therefore, it is possible to easily change the outer peripheral length formed by the trajectory connecting the surfaces of the main body to a longer length (that is, the diameter expansion) by the diameter expansion process of applying a force from the inside to the outside of the cylindrical body. In addition, the outer peripheral length formed by the locus connecting the surfaces of the main body can be easily shortened (that is, the diameter reduction) by the diameter reduction process of applying a force that tightens toward the center of the cylindrical body. Can be changed.

That is, since the recessed groove is already curved in a circular arc shape or the like and is recessed from the surface, and the surface of the tubular body is connected by the recessed groove, the tubular shape is the same. Due to the force applied to the body, the circular arc groove is bent and deformed so that the groove width expands and contracts. Since the force required for bending deformation is significantly smaller than the force required for compressive deformation that has been conventionally performed to increase or decrease the wall thickness, it is possible to extremely easily reduce the outer peripheral length.

As a result, it becomes possible to extremely easily manufacture a tubular instrument which has required much labor and time by forging, by using the method of the present invention.

According to the method of manufacturing the tubular article according to the second aspect, in the diameter expanding step, the diameter expanding member whose opening is larger than the inner diameter of the cylindrical body from the opening of the cylindrical body is used. Since it is constituted by an operation of press-fitting into the above, the recessed groove is easily bent and deformed so that the groove width becomes large by press-fitting of the diameter expanding member, and as a result, the tubular body is expanded in diameter.

According to the method for manufacturing a tubular article according to the third aspect, in the diameter reducing step, one side of the tubular body is made to face the proximal end of the tapered constriction chamber of the correction die, Since the other side portion of the cylindrical body is pressed to push the tubular body into the constriction chamber of the correction mold, the depression groove is formed so that both side wall portions of the depression groove approach each other by the pushing operation. It is deformed, and as a result, the tubular body is reduced in diameter.

According to the method of manufacturing a tubular container according to the above-mentioned claim 4, in the diameter reducing step, a narrowing strip is wound around the tubular body,
Since the narrowed line is configured to be drawn, the drawing groove is deformed so that both side wall portions of the depression groove of this portion of the tubular body approach each other by this drawing operation, and as a result, the tubular body is The diameter is reduced.

According to the method for manufacturing a tubular article according to the fifth aspect, since the diameter reducing step is configured to press the outer peripheral surface of the tubular body, the pressing point of the tubular body is appropriately selected. By setting, it becomes possible to deform the tubular body asymmetrically.

[0021]

EXAMPLE FIG. 1 is a perspective view showing an example (first example) of a cylindrical body used as a raw material in the method of the present invention. Also,
FIG. 2 is a front view of FIG. In these figures, the basic shape is shown as a circular shape, but the basic shape is not limited to a circular shape, and a regular polygon such as a triangle or larger, a rectangle, a rhombus, or a heart-shaped variant May be

As shown in these figures, the cylindrical body 1 of the present invention is formed as an integral body having a hollow inside. A plurality of recessed grooves 11 that are recessed toward the center and extend in the longitudinal direction are provided at equal intervals on the outer peripheral surface of the cylindrical body 1. Then, the cylindrical body 1 is formed with the same number of dividing surface portions 12 as the depressed grooves 11 in a state of being connected by the depressed grooves 11.

In this embodiment, the recessed groove 11 has eight threads. However, the depression groove 11 is not limited to eight rows, and may be less than eight rows or eight rows or more.

In the present embodiment, such a tubular body 1 is manufactured by extrusion molding of aluminum, but it is not limited to extrusion molding, and unevenness extending in the longitudinal direction is formed on a flat plate. Then, the plate having the concavities and convexities formed thereon may be rolled into a cylindrical shape, and the side wall portions abutting each other may be welded to form the tubular body 1.

Since the tubular body 1 of the first example is configured as described above, when the tubular body 1 is manufactured by extrusion molding, regardless of the length of the tubular body 1, the lateral direction and Since there is no connecting portion such as welding in any of the vertical directions, the appearance is beautiful. In the case where the tubular body 1 is formed by winding a plate having unevenness in a cylindrical shape and welding both side edges that are in contact with each other, there is only one welded portion, and this portion is easy. It isn't too unsightly because it can be hidden from view.

On the outer peripheral surface of the tubular body 1, recessed grooves 11 recessed toward the center and extending in the longitudinal direction and divided surface portions 12 connected by the recessed grooves 11 and extending in the longitudinal direction are alternately arranged. Since it is formed, as shown by the white arrow in FIG. 3, when a force is applied outward from the inside of the tubular body 1 toward all the recessed grooves 11, all the recessed grooves 11 in that portion are applied. Is bent and deformed to widen the groove width to form the expanded diameter cylindrical body 1x, and as shown by the solid line arrow in FIG. 3, from the outside to the central portion of the dividing surface portion 12 of the cylindrical body 1. By applying a force such as tightening toward all, all the recessed grooves 11 in that portion are bent and deformed so that the groove width is widened to become the reduced diameter cylindrical body 1y.

The diameter expanding and reducing operations are extremely easier than the conventional forging diameter expanding and reducing operations. The reason is that the recessed groove 11 is curved in an arc shape or the like and protrudes toward the inside of the tubular body 1, and the dividing surface portion 12 is connected to the recessed groove 11 at a side edge portion. The above-mentioned force contributes to the bending deformation of the arcuate groove 11 that connects the dividing surface portions 12 of the tubular body 1 that is eventually divided, but the force required for this bending deformation is the wall thickness that was conventionally used. This is because the force is much smaller than the force required for compressive deformation or extensional deformation that increases or decreases.

Therefore, as shown in FIG. 3, the tubular body 1 is divided into a diameter-expanded tubular body 1x and a diameter reduction of the tubular body 1 to a reduced-diameter tubular body 1y. The width and the thickness d of the surface portion 12 do not change. That is, FIG.
In the forging process illustrated in FIG. 1, since a change in thickness occurs, a very large amount of energy is required for the process, whereas in the present invention, only the recessed groove 11 is bent and deformed. It has the great advantage that it does not require much energy and can be easily processed.

FIG. 4 is a plan view of the cylindrical body of the second example.
In the case of the tubular body 1a of this example, the depression groove is the V-shaped groove 11
It is the same as the tubular body 1 of the first example except that it is a and that the number of grooves is large. V-shaped groove 11a
Therefore, it is easy to perform deformation to narrow the groove width, expanding the diameter,
It has the advantage that the diameter reduction operation is easy.

FIG. 5 is a plan view of the cylindrical body of the third example.
In the case of this example, the tubular body 1b is basically octagonal, and two trapezoidal grooves 11b are provided on each side of the octagon as trapezoidal grooves that are depressed in a trapezoidal shape in plan view. Then, the divided surface portion 1 protruding in an inverted trapezoidal shape at the central portion of each side portion
2b is formed, and the corner ribs 12 are provided at each corner.
b'is formed. Also in this example, the trapezoidal groove 11b
Bending deformation is easy.

In carrying out the method of the present invention, the tubular body 1 used as a raw material is not limited to the tubular bodies 1, 1a and 1b of the first to third examples, and the tubular body 1 is not limited thereto. May be any as long as it is composed of a plurality of divided surface portions 12 and a recessed groove 11 that connects the divided surface portions 12 to each other.

The method for producing a tubular product of the present invention uses the above-mentioned tubular bodies 1, 1a, 1b as a raw material to produce the tubular bodies 1, 1b.
a and 1b, the diameter expanding step of expanding the diameter of the cylindrical bodies 1, 1a, 1b by uniformly pressing outwardly from the inner peripheral surfaces, and the outer peripheral surfaces of the cylindrical bodies 1, 1a, 1b. From this, various cylindrical products are manufactured by combining a diameter reduction process of reducing the diameter of the cylindrical body by uniformly pressing it inwardly. In some cases, the tubular product can be obtained by only one of the steps without combining the above steps.

Examples of the method of the present invention using the cylindrical body 1 of the first example as a raw material will be described below with reference to FIGS. 6 to 8. First, FIG. 6 is an explanatory view in side view showing an example of the diameter expanding step according to the present invention. (A) is a state immediately before press-fitting the diameter expanding member into the tubular body, (b) is the tubular body The state where the diameter expansion member is press-fitted is shown. As shown in these drawings, in the diameter expansion step, a diameter expansion member 31 having a three-dimensional shape corresponding to the shape of the tubular body 1 after the diameter expansion is used. In this embodiment, the diameter-expanding member 31 is a conical body having a parabolic shape in a side view. The cylinder rod 3 protruding from the hydraulic cylinder is fixed to the bottom surface of the diameter expanding member 31, and the tip end of the cylinder rod 3 is fixed to a fixing means (not shown) as shown in FIG. It is set to face the opening of the body 1.

On the other hand, a portion of the cylindrical body 1 where the diameter is not enlarged is wound around the outer peripheral surface thereof with a rope 32 and fastened so that the diameter is not increased. The hydraulic cylinder is operated in such a state, and the cylinder rod 3 is projected toward the opening of the tubular body 1. Then, (b) in the figure
As shown in, the diameter-expanding member 31 provided at the tip of the cylinder rod 3 projects into the inside of the tubular body 1 to expand the tubular body 1.

Next, the diameter reduction step according to the present invention will be described. FIG. 7: is explanatory drawing of the side surface cross section which shows an example of the diameter reduction process (the diameter reduction process of a 1st example) which concerns on this invention. As shown in this figure, in order to reduce the diameter, a correction mold 2 having a narrowed chamber 21 having a tapered inner wall surface inside is used. The constriction chamber 21 of the correction mold 2 is set to have a shape along the outer peripheral surface of the tapered cylindrical body 1 excluding the irregularities to be obtained, and the insertion port 22 provided on the left end wall surface thereof.
Has an outer diameter slightly larger than the outer diameter of the tubular body 1 obtained by extrusion molding used as a raw material. A jig insertion opening 23 for extrusion is formed on the right end wall surface.

On the other hand, on the right side of the insertion opening 22 of the straightening mold 2, a hydraulic cylinder (not shown), which is a pressing means, is arranged at a considerable interval, and the tip end of the cylinder rod 3 protruding from this hydraulic cylinder. Are opposed to the insertion port 22.

The cylindrical body 1 as a raw material is mounted between the cylinder rod 3 and the insertion opening 22 of the correction mold 2, and in this state, a hydraulic cylinder (not shown) is operated to cause the cylinder rod 3 to move. Thus, it is pushed into the stenosis chamber 21 through the insertion opening 22. Then, the tubular body 1 receives a force from the slanted inner wall surface of the constriction chamber 21 toward the center, and as the inside of the constriction chamber 21 progresses, the recessed groove 11 is bent and deformed so as to narrow the groove width, and the tip side gradually. The outer diameter becomes smaller.

Then, with the tubular body 1 completely pushed into the constriction chamber 21, a tapered tubular body is obtained. When a tubular body is obtained in the constriction chamber 21, the cylinder rod 3 is pulled back, an appropriate jig is inserted from the jig insertion port 23, and a force is applied in the direction of the constriction chamber 21 to insert the tubular body. It can be pulled out from the mouth 22.

A rope is used as the pushing means instead of the cylinder rod 3, and this rope is used as the jig insertion port 2
3 into the stenosis chamber 21, and the distal end portion thereof is inserted into the tubular body 1
Alternatively, the tubular body 1 may be introduced into the insertion port 22 by pulling the rope.

Next, another diameter reducing step according to the present invention will be described. FIG. 8: is explanatory drawing of the front sectional view which shows the other example (diameter reduction process of 2nd example) of the diameter reduction process which concerns on this invention, (a) is the state which attached the rope for stenosis to the main body. ,
(B) shows a state in which the outer peripheral length of the main body is reduced by pulling on the narrowing rope. In the case of this example, as shown in FIG. 7, a rope 4 as a narrowing strip is wound around the outer peripheral surface of the raw material tubular body 1, and one side portion or both side wall portions of this rope 4 are drawn to squeeze this portion. The groove width of the depressed groove 11 is narrowed.

In order to facilitate the operation with the rope 4, the narrowing jig 5 that supports the rope 4 is used in this embodiment. A vertical hole 51 that opens upward is provided in the center of the constricting jig 5, and two bolts 52 are screwed into the bottom of the narrowing jig 5 so that the tip end is located in the vertical hole 51. Both ends of the rope 4 are connected to the tip end of the bolt 52, and by rotating the bolt 52 forward and backward around the axis, the rope 4 can tighten and loosen the tubular body 1. There is.

Therefore, by rotating the bolt 52 in the direction in which the tubular body 1 is tightened with the rope 4, the groove width of the recessed groove 11 of the tubular body 1 is narrowed as shown in (b), and this portion is twisted. It will be in a state of being broken. According to this method, since the outer peripheral length can be reduced at an appropriate position of the tubular body 1, it is possible to manufacture a tubular body having a plurality of twisted portions.

FIG. 9 is a perspective view showing an example of a cylindrical container manufactured by the method of the present invention. In this example,
The cylindrical object is prize cup 6. Top opening 61 of this prize cup 6
The diameter is increased by executing the diameter increasing step shown in FIG. 6, and the entangled portion 62 of the prize cup 6 is formed by executing the diameter reducing step shown in FIG. The bottom 63 of the prize cup 6 has the same diameter as the original cylindrical material 1.

In FIG. 9, only the prize cup 6 is shown as an example of the cylindrical bowl, but the cylindrical bowl obtained by the method of the present invention is not limited to the above prize cup 6, and only the diameter reduction step is performed. In the case of applying, a flag pole, a carp climbing pole, a pole for outdoor lighting, a carport support, etc. are mentioned, and as both of the diameter expansion process and the diameter reduction process are applied,
Struts and beams as building materials, ornaments and various columns for interior decoration, fences for parks, railings for bridges and pedestrian bridges, balconies and terraces, advertising towers and signs, bats, To list sports equipment such as ski poles, prized goods such as winning cups and cups, various poles used as stage equipment, various household goods, long items used decoratively or for design purposes. You can

Although the cylindrical body having the cylindrical shape or the regular polygonal cylinder shape has been described above, the cylindrical body of the present invention is not limited to the cylindrical shape or the regular polygonal cylinder shape. Instead, the sectional view may be rectangular or the like.
Therefore, an example of a tubular body whose cross-sectional view does not have a circular shape or a regular polygonal shape will be described below.

FIG. 10 is a perspective view showing a fourth example of the cylindrical body of the present invention. The cylindrical body 1c of this example has a vertically long rectangular shape in a side view from the left side of the figure, and its peripheral surface is provided with unevenness extending in the horizontal direction. And
The V-shaped groove 11a is formed in these concave portions, and the dividing surface portion 12c is formed at the top of the convex portions.
That is, the outer peripheral surface of the cylindrical body 1c is like a fold of an accordion.

For such a tubular body 1c,
The diameter reduction step of the third example according to the present invention is applied. Figure 11
[Fig. 8] is an explanatory view showing a diameter reducing step of the third example. As shown in this figure, the tubular body 1c is first brought into a state in which the upper portion in this figure is stopped by the stopper 33. on the other hand,
A cylinder rod 3 for reducing the diameter of the body portion of the tubular body 1c is provided, and an arcuate compression member 34 is attached to the tip end portion thereof. The compression member 34 and the stopper 33 are positioned so as to sandwich the tubular body 1c, and the cylinder rod 3 is projected so that the arcuate surface of the compression member 34 causes the tubular body 1c to move downward. The side portion is strongly pressed as shown by the arrow.

Since the diameter reducing step of the third example is configured as described above, the cylindrical body 1c pressed by the compression member 34 is V-shaped groove 11a along the arc surface of the compression member 34.
The groove width is deformed so that the groove width is narrowed to obtain an arch member 6a as shown by the chain double-dashed line in FIG.

FIG. 12 is an explanatory view showing a modification of the diameter reducing step of the third example according to the present invention. In this case,
Instead of using the stopper 33, the pair of compression members 3
4. The tubular body 1c is sandwiched by 4 and at the same time, the pair of compression members 3
4 is made to project. By simultaneously projecting the pair of compression members 34, a double arch member 6b as shown by a two-dot chain line in the figure is obtained. Instead of arranging the pair of compression members 34, one compression member 34 is
Instead of a stopper having the same arcuate surface formed on the front side, the tubular body 1c may be set between this stopper and the other compression member 34 so that only the other compression member 34 projects. .

FIG. 13 is a perspective view showing an example of the cylindrical member manufactured by the diameter reducing step of the third example of the present invention, that is, the arch member 6a. Such arch member 6
The a can be applied as a decorative member on the upper part of the door frame of the entrance.

FIG. 14 is a perspective view showing an example of a container, that is, an arch member 7 not having a cylindrical shape, which is manufactured by the diameter reducing step of the third example according to the present invention for a corrugated plate. This arch member 7 can be manufactured by vertically dividing the arch member 6a shown in FIG. 13 into two pieces, or by applying the diameter reducing step of the third example using corrugated sheet as a raw material. It is also possible to manufacture. Also for such an arch member 7 having only one surface, it is possible to manufacture the same arch member 7 as the above-mentioned double arch member 6b in which a pair of arches face each other.

[0052]

As described above in detail, in the method for manufacturing a tubular container according to the present invention, a plurality of recessed grooves extending in the longitudinal direction which are recessed toward the center are formed on the outer peripheral surface of the cylindrical body at substantially equal intervals. Is a method of manufacturing a tubular article by radially deforming the formed tubular body, wherein the diameter of the tubular body is expanded by strongly pressing outward from the inner peripheral surface of the tubular body. Using either one or both of the diameter expansion step for reducing the diameter of the tubular body by inwardly pressing from the outer peripheral surface of the tubular body. Is.

Therefore, the outer peripheral length formed by the locus connecting the surface of the main body is easily changed to be long (that is, the diameter expansion) by the diameter expansion process of applying a force from the inside to the outside of the cylindrical body. In addition, the outer peripheral length formed by the locus connecting the surfaces of the main body can be shortened (that is, the contraction can be shortened) by the diameter reducing process of applying a force for tightening the cylindrical body toward the center thereof. Diameter) can be changed.

That is, the recessed groove has already been curved in a circular arc shape or the like and is recessed from the surface, and the surface of the tubular body is in a state of being connected by the recessed groove. Due to the force applied to the body, the circular arc groove is bent and deformed so that the groove width expands and contracts. Since the force required for bending deformation is significantly smaller than the force required for compressive deformation that has been conventionally performed to increase or decrease the wall thickness, it is possible to extremely easily reduce the outer peripheral length.

As a result, it becomes possible to manufacture a tubular article which has required much labor and time by conventional forging, and which can be manufactured very easily by using the method of the present invention, which is advantageous.

If the diameter expanding step is constituted by an operation of press-fitting a diameter-expanding member whose body portion is larger than the inner diameter of the cylindrical body into the tubular body through the opening of the tubular body, the diameter-expanding member is press-fitted. The recessed groove is easily bent and deformed so that the groove width becomes large, and as a result, the tubular body is easily expanded in diameter.

The diameter reducing step is set so that one side portion of the tubular body faces the base end portion of the tapered constriction chamber of the correction die, and the other side portion of the tubular body is pressed to press the tubular body. If it is configured to be pushed into the constriction chamber of the correction die, the pushing operation deforms the recessed groove so that both side wall portions of the recessed groove come close to each other, and as a result, the tubular body is easily reduced in diameter. It

Further, in the diameter reducing step, if the narrowed line is wound around the tubular body and the narrowed line is drawn, the side wall of the recessed groove of the tubular body in this portion is drawn by this drawing operation. The recessed groove is deformed so that the parts come close to each other, and as a result, the tubular body is easily reduced in diameter.

Further, if the diameter reducing step is constituted so as to press the outer peripheral surface of the tubular body, the tubular body can be deformed asymmetrically by appropriately setting the pressing portion of the tubular body. Since it becomes possible, it is possible to obtain a tubular article having a variety of designs.

[Brief description of drawings]

FIG. 1 is a perspective view showing an example (first example) of a tubular body according to the present invention.

FIG. 2 is a front view of the tubular body of FIG.

FIG. 3 is a cross-sectional view of the tubular body of FIG. 1, in which the expanded state and the reduced diameter state are also illustrated together.

FIG. 4 is a plan view showing a second example of the tubular body of the present invention.

FIG. 5 is a plan view showing a third example of the tubular body of the present invention.

FIG. 6 is an explanatory side view showing an example of a diameter expanding step according to the present invention, in which (a) is a state immediately before the diameter expanding member is press-fitted into the tubular body, and (b) is an expanding state of the tubular body. The state where the diameter member is press-fitted is shown.

FIG. 7 is an explanatory side cross-sectional view showing a diameter reducing step of the first example according to the present invention.

FIG. 8 is an explanatory view of a front cross-sectional view showing a diameter reducing step of a second example according to the present invention, (a) shows a state in which a stenosis rope is attached to the main body, and (b) shows a stenosis rope. Shows a state in which the outer peripheral length of the main body is reduced by pulling.

FIG. 9 is a perspective view showing an example of a tubular product manufactured by the method of the present invention.

FIG. 10 is a perspective view showing a fourth example of the tubular body of the present invention.

FIG. 11 is an explanatory view showing a diameter reducing step of the third example according to the present invention.

FIG. 12 is an explanatory diagram showing a modified example of the diameter reducing step of the third example according to the present invention.

FIG. 13 is a perspective view showing an example of a tubular device manufactured by the diameter reducing step of the third example according to the present invention.

FIG. 14 is a perspective view showing an example of a container manufactured by a diameter reducing process of a third example according to the present invention for a corrugated plate.

FIG. 15 is a perspective view showing an example of a conventional tubular device.

FIG. 16 is a perspective view showing an example of a tubular instrument manufactured by conventional forging.

FIG. 17 is a cross-sectional view of a tubular body manufactured by conventional forging, in which the expanded state and the reduced diameter state are also illustrated together.

[Explanation of symbols]

 1, 1a, 1b, 1c Cylindrical body 11 Recessed groove 11a V-shaped groove 11b Trapezoidal groove 12, 12c Divided surface part 2 Correction die 21 Narrowing chamber 22 Insertion port 3 Cylinder rod 4, 32 Rope 5 Narrowing jig 6 Award cup 6a, 7 arch member 6b double arch member

Claims (5)

[Claims] 1. A tubular article is formed by radially deforming a tubular body, in which a plurality of recessed grooves extending in the longitudinal direction, which are depressed toward the center, are formed on the outer peripheral surface of the tubular body at substantially equal intervals. A method of manufacturing, the diameter expanding step of expanding the diameter of the tubular body by applying pressure outward from the inner circumferential surface of the tubular body, and from the outer circumferential surface of the tubular body to the inside. A method of manufacturing a tubular container, wherein one or both of the diameter reducing steps of reducing the diameter of the tubular body by applying a strong pressure toward the same are used. 2. The expanding member according to claim 1, wherein, in the expanding step, a expanding member whose body portion is larger than the inner diameter of the cylindrical member is press-fitted into the cylindrical member through the opening of the cylindrical member. A method for manufacturing a tubular product. 3. In the step of reducing the diameter, one side portion of the tubular body is opposed to a base end portion of a tapered constriction chamber of a correction die,
2. The method for producing a tubular instrument according to claim 1, wherein the other side of the tubular body is pressed to press the tubular body into the narrowing chamber of the correction mold. 4. The method for producing a tubular container according to claim 1, wherein in the step of reducing the diameter, a narrowed strip is wound around the tubular body and the narrowed strip is drawn. 5. The method for manufacturing a tubular container according to claim 1, wherein an outer peripheral surface of the tubular body is pressed in the diameter reducing step.