JP2000351021A - Flange forming method and apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a flange forming method and a device capable of easily forming a flange having a relatively large diameter without causing cracks by pressing a work in an axial direction and securely buckling the work. I will provide a. A pressing surface of a die and a sleeve.
By pressing the surface of the end portion Wa of the work W in the axial direction at 0a and 12a, the work W is moved in the opposite direction (the inside of the work W) to the side on which the flange F of the work W is protruded so as to form the flange F. The workpiece W is buckled to a predetermined amount and the workpiece W is further buckled while being fed to the side (outside of the workpiece W) on which the flange W of the end Wa of the workpiece W protrudes to form a flange F. Yield.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method and an apparatus for forming a flange, and more particularly to a method and an apparatus for forming a flange by pressing a hollow pipe-shaped workpiece in the axial direction to buckle it. It is.

[0002]

2. Description of the Related Art For example, when a flange F is formed on a hollow pipe-shaped workpiece W in order to obtain a product used for a fluid conduit or the like, the workpiece W is inserted as shown on the left side from an axis C in FIG. Conventionally, it is common practice to prepare a flange F ′ having a hole Fb ′ that can be formed separately from the work W and insert the work W through the hole Fb ′ and fix it by welding or the like.

[0005] Further, as shown to the right from the axis C in FIG. 5, it has been conventionally considered to form a flange F by pressing a hollow pipe-shaped workpiece W in the axial direction to buckle it. When the flange F is formed in this way, as shown in FIG. 2, the pressing surfaces 20a and 22a for pressing the work W of the flange forming apparatus in the axial direction are generally substantially perpendicular to the axial direction. Is formed.

On the other hand, when the product on which the flange F is formed is a drive shaft or the like to which a relatively large load can be applied, the work W ′ is heated as shown to the left from the axis C in FIG. Upsetting by cold forging or cold forging to form the flange F has also been generally performed conventionally.

When a product such as a drive shaft to which a relatively large load can be applied is obtained, for the purpose of reducing the weight of the product, as shown in the right side of the axis C in FIG. When the flange W is formed by buckling the work W in the shape of a circle, the thickness t2 of the work W is relatively thicker than the thickness t1 of the work W shown to the right from the axis C in FIG. Will be used.

Further, as a technique for performing a so-called edge bending on a terminal of a panel work, Japanese Patent Application Laid-Open No. Sho 60-2103 is disclosed.
No. 27 and Japanese Patent Application Laid-Open No. 9-262624 are known. And Japanese Patent Laid-Open No. 60-2103
No. 27 describes that the base end of the folded flange (the end of the folded flange) is formed in a substantially cylindrical shape. Further, Japanese Unexamined Patent Publication No.
Japanese Patent Publication No. 262624 discloses a conventional 180-degree bending ram having a bulge for escape.

[0007]

However, as shown in the left side from the axis C in FIG. 5, the work W is inserted into the hole of the separate flange F 'and welded or the like. In the case where the work W is fixed, a flange F 'separate from the work W is prepared, a hole Fb' for inserting the work W is formed in the flange F ', and a welding for fixing the two is performed. And the like, there is a problem that the number of steps is increased and the manufacturing cost is increased.

[0008] In the above-mentioned prior art, as shown to the right from the axis C in FIG.
Is formed, the work W is buckled and the diameter is increased by buckling, so that the circumferential end of the formed flange F is pulled in the circumferential direction Fa. If the diameter of the workpiece W is increased beyond the tensile limit, a crack (crack) extending in the radial direction occurs at the peripheral end Fa of the formed flange F, so that the flange F having a large diameter exceeding the tensile limit is generated. Cannot be formed. In particular, when forming a large-diameter flange F, as shown in FIG. 7, wrinkles or undulations R are formed on the formed flange F because the buckling progress speed and directionality vary depending on the portion. There was a problem that would occur.

Furthermore, the flange F
In particular, when the flange F is formed on a relatively thick work W (see t2 on the right side of the axis C in FIG. 6), as shown in FIG. Since the peripheral edge front end Fa is bent by approximately 180 degrees, the outer crack Sa (the upper broken line circle shown in an enlarged scale in FIG. 8) and the internal crack Sb (in the enlarged side in FIG. 8) extending in the circumferential direction at the peripheral edge end Fa of the flange F. The lower chain line circle shown in FIG. When such cracks Sa and Sb occur, the integral formation of the flange F has to be abandoned.

On the other hand, of the above-mentioned conventional techniques, as shown to the left from the axis C in FIG. 6, when the work W 'is upset by hot or cold forging, Since the work W 'is inevitably limited to a solid work, there is a problem in that the work W requires a large amount of material and requires a high manufacturing cost. Further, in this case, since the product becomes heavy and the inertia force increases, there is also a problem that a problem occurs when the product is used as a rotating shaft.

Furthermore, in particular, a relatively thick work W
In the case where the flange F is formed on the right side of the axis C in FIG. 6 (see t2 on the right side of the axis C in FIG. 6), as shown in FIG. As shown in the left side of FIG. 2), there is a problem that a large load is applied to a device for forming the flange F by pressing the work W in the axial direction.

The technology disclosed in Japanese Patent Application Laid-Open Nos. Sho 60-210327 and Hei 9-262624 is for applying a substantially linear edge bend to a terminal of a panel work. Unlike a technique for forming a flange by pressing a hollow pipe-shaped work in the axial direction to buckle it as in the invention, a 180-degree bending ram cannot be applied to the present invention.

SUMMARY OF THE INVENTION The present invention has been made in view of the above problems, and a work having a relatively large diameter can be easily formed by pressing a work in an axial direction to reliably buckle the work. It is an object of the present invention to provide a method and apparatus for forming a flange, which can prevent the occurrence of such problems and improve the yield of products.

[0014]

According to a first aspect of the present invention, there is provided a method for forming a flange by pressing a hollow pipe-shaped workpiece in an axial direction to buckle the workpiece. Wherein the workpiece is buckled to a predetermined amount while being fed on the side where the flange is not formed.

According to a second aspect of the present invention, in order to achieve the above object, in the first aspect of the present invention, a workpiece buckled to a predetermined amount is fed to a side on which the flange of the workpiece is formed. It is further characterized by buckling the work.

According to a third aspect of the present invention, there is provided a method for forming a flange by pressing a hollow pipe-shaped workpiece in an axial direction to buckle the workpiece, in order to achieve the above object. The present invention is characterized in that an axial force is applied so that the base end portions of the workpieces come into contact with each other without crushing the peripheral end of the formed flange.

According to a fourth aspect of the present invention, there is provided an apparatus for forming a flange by pressing a hollow pipe-shaped work in an axial direction to buckle the work, in order to achieve the above object. A pressing member that presses the work,
It is characterized in that the pressing surface is inclined so as to buckle while feeding the side of the work where the flange is not formed, and that the work is allowed to buckle to a predetermined amount.

According to a fifth aspect of the present invention, there is provided an apparatus for forming a flange by pressing a hollow pipe-shaped work in an axial direction to buckle the work, in order to achieve the above object. The opposing pressing surfaces of the pressing members to be pressed are formed in such a shape that stress concentration does not occur at the peripheral end of the formed flange.

According to the first aspect of the present invention, when the hollow pipe-shaped work is initially pressed in the axial direction, the end face of the work where the flange is not formed is pressed first to buckle the work to a predetermined amount. By feeding the work on the side where the flange is not formed before the side where the flange is formed, the work is reliably buckled so that the part to be the flange protrudes in the direction in which the work is formed.

According to a second aspect of the present invention, in the first aspect of the present invention, the side of the end face of the buckled work which has been buckled to a predetermined amount is pressed in advance, until the flange is finally formed. Buckles the work. When the side forming the flange is pressed and sent in advance, the peripheral edge of the formed flange is bent substantially 180 degrees without being subjected to tension. Therefore, a problem such as a crack does not occur in the work.

According to the third aspect of the present invention, the work is buckled so that the base end portions of the flange finally formed on the work are in contact with each other, and the peripheral end of the flange formed on the work is formed. So as not to crush
Apply axial force to form a flange. Since the peripheral edge of the flange is not crushed and stress is not concentrated, no crack occurs.

According to the fourth aspect of the present invention, the pressing surface of the pressing member that presses the end face of the hollow pipe-shaped work in the axial direction is formed so as to be inclined. Is pressed first to buckle the work to a predetermined amount. Work is
Since the side on which the flange is not formed is fed before the side on which the flange is formed, the portion serving as the flange is reliably buckled so as to protrude in the direction in which the flange is formed.

According to the fifth aspect of the present invention, the workpiece is buckled, and a flange is formed by applying an axial force so that the base ends of the flange finally formed on the workpiece come into contact with each other. At this time, since the pressing member is formed in such a shape as not to cause stress concentration at the peripheral end of the flange where the opposing pressing surfaces are formed, no crack is generated.

[0024]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS First, a first embodiment of a flange forming apparatus according to the present invention will be described in detail with reference to FIG. In the drawings, the same reference numerals denote the same or corresponding parts. It should be noted that FIG. 1 shows different states on the left and right of the axis C of the workpiece W.

The flange forming apparatus of the present invention generally includes a die 10 and a punch 11 provided on a ram (not shown) of a press, and a sleeve 12 disposed opposite to the die 10 and the punch 11. A hollow pipe-shaped work W is supported on the inner periphery of the sleeve 12, and the ram is driven to move the die 10 and the punch 11 close to the sleeve 12.
a is pressed in the axial direction and buckled so as to protrude outward to form a flange F. Then, the pressing surfaces 10a and 12a of the sleeve 10 and the die 10 pressing the end Wa of the work W as a pressing member face the side where the flange F of the work W is not formed (that is, the inside of the hollow pipe-shaped work W). The die 10 and the sleeve 12 are inclined so as to buckle while being fed, and are formed so as to buckle the work W to a predetermined amount.

The die 10 is a cushion (not shown).
The punch 11 is mounted coaxially inside the ram. And the die 10
A predetermined amount of relative movement with respect to the punch 11 in the direction of the axis C is possible. A sleeve 12 is provided on the inner peripheral surface of the die 10.
A workpiece insertion portion 15 is formed in which the workpiece W is inserted between the workpiece W and the punch 11 when the workpiece W is moved closer to the punch 11.

On the other hand, the sleeve 12 has a hole 16 through which the punch 11 is inserted when the ram is driven close to the center.
The work insertion part 17 which inserts and supports is formed.

Further, the pressing surfaces 10a and 12a of the work insertion portions 15 and 17 of the die 10 and the sleeve 12 which come into contact with and press against the surface of the end Wa of the work W press the surface of the end Wa of the work W. At the beginning, the inside of the surface of the end Wa of the work W on the side opposite to the side on which the flange F is protruded is formed more than the outside of the surface of the end Wa of the work W on which the flange F is protruded. Each is inclined so as to be pressed first. Opposing surfaces 10b, 12b of the outer periphery of the die 10 and the sleeve 12 oppose each other.
As shown in the right side of FIG. 1, when the work W is buckled to a predetermined amount, the work W is set to contact each other to limit the buckling of the work W. Furthermore, the workpiece insertion portions 15 and 17 of the die 10 and the sleeve 12 are opposed to the facing surface 10.
Work shape guide portions 10c, 10c, which guide and transfer the shape W of the buckled work, respectively, between the radial directions b and 12b.
12c is formed.

Next, an embodiment of the flange forming method according to the present invention will be described in detail with reference to FIGS. 1 and 2 by using a flange forming apparatus having the above-described configuration. In FIG. 2, as in FIG.
Note that different states are shown on the left and right of the axis C of FIG.

The flange forming method of the present invention generally forms the flange F of the work W by pressing the surface of the end Wa of the work W in the axial direction with the pressing surfaces 10a and 12a of the die 10 and the sleeve 12. The workpiece W is buckled to a predetermined amount while being fed on the side opposite to the side to be protruded (ie, the inside of the work W). The workpiece is further buckled while being fed on the side (i.e., the outside of the workpiece W) that projects to form the flange F of the surface.

When the flange F is formed on the hollow pipe-shaped work W, the ram is first raised to separate the die 10 and the punch 11 from the sleeve 12, and the work is inserted into the work insertion portion 17 of the sleeve 12. insert. At this time, since the pressing surface 12a of the sleeve 12 is formed so as to be inclined, the inside of the surface of the lower end Wa of the work W on the side opposite to the side on which the flange F projects to form the flange F is formed. It is placed on the pressing surface 12 a, and the lower outer peripheral surface of the work W is held on the inner peripheral surface of the work insertion portion 17 of the sleeve 12.

Next, the ram (not shown) is driven to move down so that the die 10 and the punch 11 are brought close to the sleeve 12. At this time, the punch 11 is inserted inside the work W above, and is held between the work insertion portion 15 of the die 10 and the punch 11. Similarly to the sleeve 12, since the pressing surface 10a of the die 10 is formed so as to be inclined, the inner side of the surface of the upper end Wa of the work W, which does not form a flange, is first formed on the pressing surface 10a of the die 10. (See left of axis in FIG. 1). And
The inclined pressing surface 10a, 1 of the die 10 and the sleeve 12
By being pressed between 2a, the work W is pressed before the outer surface forming the flange F of the end Wa on the inner side of the upper and lower ends Wa on which the flange F is not formed. You. That is, the inside of the end Wa of the work W where the flange F is not formed is fed before the outside where the flange F is formed (see the right arrow of the chain line in FIG. 1). As a result, the portions of the work W that are not held by the die 10 and the work insertion portions 15 and 17 of the sleeve 12 are reliably buckled so as to protrude outward to form the flange F. When the outer facing surfaces 10b, 12b of the die 10 and the sleeve 12 come into contact with each other, the work W buckles along the work shape guides 10c, 12c of the die 10 and the sleeve 12. The inclination of the pressing surfaces 10a and 12a between the die 10 and the sleeve 12 is transferred to the end Wa of the work W. The step of buckling the work W to a predetermined amount is referred to as a preforming step for convenience.

When the preforming step is completed, a finishing step for finally forming the flange F is performed on the work W as shown in FIG. In this finishing step, the die 20 and the sleeve 22 having the general pressing surfaces 20a and 22b substantially orthogonal to the axis C are used instead of the die 10 and the sleeve 12 in which the pressing surfaces 10a and 12a are inclined as described above. Can be Such a pressing surface 20a,
When pressing and buckling the work W for which the preforming step has been completed by 22a, the work W to which the inclination of the pressing surfaces 10a and 12a of the die 10 and the sleeve 12 has been transferred in the preforming step is the end Wa of the end Wa. The outside protruding to form the surface flange F is pressed earlier than the inside of the surface of the end Wa that does not form the flange F. That is, the outside of the work W where the flange F is formed is sent before the inside where the flange F is not formed (see the left arrow of the chain line in FIG. 2). Thus, the buckled portions of the work W that are not held by the die 20 and the work insertion portions 25 and 27 of the sleeve 22 are buckled so as to protrude further outward to form the flange F. When the outer facing surfaces 20b, 22b of the die 20 and the sleeve 22 come into contact with each other, the die 20
The flange F is pressed by the flange pressing portions 20d and 22d formed substantially in parallel with the sleeve 22 so that the peripheral end Fa of the work W on which the flange F is formed is substantially 180.
The workpiece W is bent once (see the right side of the dashed line in FIG. 2), but the outer side of the workpiece W forming the flange F is fed ahead of the inner side of the workpiece W not forming the flange F. Since no tensile stress is generated on the outside that is bent so much, no crack is generated.

Next, a second embodiment of the flange forming apparatus of the present invention will be described with reference to FIG. Note that the same or corresponding parts as those of the above-described embodiment are denoted by the same reference numerals, and description thereof is omitted.

The flange forming apparatus according to the present embodiment is an apparatus for forming a flange F by pressing a work W in the axial direction and buckling the work W. A die 30 for pressing the flange F of the work W and a die 30 are provided. The opposed flange pressing surfaces 30d and 32d of the sleeve 32 are formed so as to have a predetermined relative angle α such that the temporary interval increases toward the peripheral end Fa of the flange F.

The pressing surfaces 30a and 32a for pressing the surfaces of the end portions Wa of the work W of the work insertion portions 35 and 37 of the die 30 and the sleeve 32 in this embodiment are formed so as to be substantially orthogonal to the axis C. ing. The lower surface of the die 30 serving as the flange pressing surface 30d is formed so as to be inclined so that the inside with respect to the axis C projects outward. Similarly, the upper surface of the sleeve 32 serving as the flange pressing surface 32d is also formed in a state where the inner side with respect to the axis C is inclined so as to protrude outward. With this configuration, when the die 30 is brought close to the sleeve 32, the base end F of the flange F is formed without crushing the peripheral end Fa of the flange F formed on the work W.
The inner peripheral surfaces of the workpiece W at the portion b are in contact with each other.

Next, a second embodiment of the flange forming method of the present invention will be described in more detail when a flange forming apparatus configured as shown in FIG. 3 is used. Note that the same or corresponding parts as those of the above-described embodiment are denoted by the same reference numerals, and description thereof is omitted. The flange forming method of the present invention is a method of forming a flange F by pressing a hollow pipe-shaped workpiece W in the axial direction and buckling the same, and a peripheral edge Fa of the flange F formed on the workpiece W Without crushing the base end Fb of the workpiece W
Are applied in the axial direction so that the portions to be in contact with each other.

In the flange forming apparatus shown in FIG. 3, first, the die 30 and the punch 31 are separated from the sleeve 32, and the work W is inserted into the work insertion portion 37 of the sleeve 32. Below the work W, the outer peripheral surface is held by the inner peripheral surface of the work insertion portion 37 of the sleeve 32. Next, the die 30 and the punch 31 are attached to the sleeve 32.
, The upper part of the work W
Is inserted, the work insertion portion 35 of the die 30 and the punch 3
1 is held. When the die 30 and the punch 31 are further brought close to the sleeve 32, the axis C of FIG.
Of the work W, the portions not held by the die 30 and the work insertion portions 35 and 37 of the sleeve 32 are securely buckled so as to protrude outward to form the flange F. . Die 30 and punch 3
When the workpiece 1 is brought close to the sleeve 32, as shown on the right side of the axis C in FIG. When pressed, the flange F is formed. At this time, as shown in FIG.
The inner peripheral surfaces of the workpiece W at the base end portion Fb contact each other. However, the flange F of the workpiece W
Pressing portion 30d of die 30 for pressing a portion to be formed
And the flange pressing portion 32d of the sleeve 32 is
Has a predetermined relative angle α such that the temporary interval becomes wider toward the peripheral edge Fa of the flange F.
a is bent with a predetermined radius of curvature without being crushed. Therefore, since the tensile stress generated outside the formed flange F is reduced, no crack occurs.

Next, a third embodiment of the flange forming apparatus of the present invention will be described with reference to FIG. Note that the same or corresponding parts as those of the above-described embodiment are denoted by the same reference numerals, and description thereof is omitted.

The flange forming apparatus according to this embodiment is an apparatus for forming a flange F by pressing a work W in the axial direction and buckling the work W. A die 40 for pressing the flange F of the work W and a die 40 are provided. Of the sleeve 42,
The annular recesses 40e and 42e are formed at positions corresponding to the peripheral edge Fa of the flange F, respectively.

The annular concave portions 40e and 42e of the die 40 and the sleeve 42 in this embodiment have substantially semicircular cross-sections, respectively, so that the cross section when the die 40 and the sleeve 42 are abutted is substantially circular. Is formed.
In addition, from the position corresponding to the base end portion Fb of the flange F of the die 40 and the sleeve 42 to the concave portions 40e and 42e, they are formed in parallel at substantially the same interval as the thickness of the flange F formed on the work W. . With this configuration, when the die 40 is brought close to the sleeve 42, the cross-section is formed into a substantially circular pipe having a predetermined radius without crushing the peripheral end Fa of the flange F formed on the work W. Then, only the portion from this portion to the base end Fa of the flange F is crushed, and the inner peripheral surfaces of the work W come into contact with each other.

Next, a third embodiment of the flange forming method of the present invention will be described in more detail when a flange forming apparatus configured as shown in FIG. 4 is used. Note that the same or corresponding parts as those of the above-described embodiment are denoted by the same reference numerals, and description thereof is omitted. The flange forming method of the present invention is a method of forming a flange F by pressing a hollow pipe-shaped workpiece W in the axial direction and buckling the same, and a peripheral edge Fa of the flange F formed on the workpiece W Is formed in a pipe-shaped cross section so as not to be crushed, and an axial force is applied so that only a portion of the work W which becomes a base end portion of the flange F is in contact with each other.

In the flange forming apparatus shown in FIG. 4, first, the die 40 and the punch 41 are separated from the sleeve 42, and the work W is inserted into the work insertion portion 47 of the sleeve 42. Below the work W, the outer peripheral surface is held on the inner peripheral surface of the work insertion portion 47 of the sleeve 42. Next, the die 40 and the punch 41 are attached to the sleeve 42.
, The upper part of the work W
Is inserted, and the work insertion portion 45 of the die 40 and the punch 4
1 is held. When the die 40 and the punch 41 are further moved closer to the sleeve 42, as shown on the left side of the axis C in FIG. 4, portions of the work W that are not held by the die 40 and the work insertion portions 45 and 47 of the sleeve 42. Are securely buckled so as to protrude outward to form a flange F. Further, when the die 40 and the punch 41 are brought closer to the sleeve 42, the work W is pressed between the lower surface of the die 40 and the upper surface of the sleeve 42 to form the flange F, as shown on the right of the axis C in FIG. Will be done. At this time, as shown in FIG.
Are in contact with each other such that the inner peripheral surfaces of the workpiece W at the base end portion Fb are crushed. However,
By forming the annular recesses 40e and 42e at positions corresponding to the peripheral end Fa of the flange F of the die 40 and the sleeve 42 pressing the flange F of the work W, the peripheral end Fa of the flange F is not crushed. It is formed in a pipe shape having a predetermined radius of curvature and a substantially circular cross section. Accordingly, since the tensile stress generated outside the formed flange F is reduced, no crack occurs.

The present invention is not limited to the embodiment described above. For example, after the preforming step is performed by the flange forming apparatus shown in FIG.
A finishing step of forming a final flange may be performed by the flange forming apparatus shown in FIG.

[0045]

According to the first aspect of the present invention, the workpiece is buckled to a predetermined amount while being fed on the side where the flange of the workpiece is not formed, so that the workpiece is pressed in the axial direction and buckled reliably. A flange forming method capable of easily forming a flange having a relatively large diameter can be provided.

According to the second aspect of the present invention, in the first aspect of the present invention, the work buckled to a predetermined amount is further buckled while feeding the work on the side where the flange of the work is formed. It is possible to provide a flange forming method capable of preventing the occurrence of defects such as cracks and the like and improving the yield of products.

According to the third aspect of the present invention, by applying an axial force so that the base end portions of the work come into contact with each other without crushing the peripheral end of the flange formed on the work, cracks or the like can be obtained. Thus, it is possible to provide a flange forming method capable of preventing the occurrence of such a problem and improving the yield of products.

According to the fourth aspect of the present invention, the pressing member for pressing the work is tilted so as to buckle while feeding the side of the work where the flange is not formed, and the work buckles to a predetermined amount. Is formed so that the workpiece can be pressed in the axial direction and securely buckled to easily form a flange with a relatively large diameter. Can be provided, and a flange forming apparatus capable of improving the product yield can be provided.

According to the fifth aspect of the present invention, the opposing pressing surfaces of the pressing member for pressing the work are formed in such a shape that stress concentration does not occur at the peripheral edge of the formed flange. It is possible to provide a flange forming apparatus capable of preventing the occurrence of such troubles and improving the yield of products.

[Brief description of the drawings]

FIG. 1 is an end view for explaining a preforming step of a first embodiment of a flange forming method and apparatus according to the present invention.

FIG. 2 is an end view for explaining a finishing step of the first embodiment of the flange forming method and apparatus according to the present invention.

FIG. 3 is an end view for explaining a second embodiment of the method and apparatus for forming a flange according to the present invention.

FIG. 4 is an end view for explaining a third embodiment of a flange forming method and apparatus according to the present invention.

FIG. 5 is an end view for explaining a case where a flange is formed by a conventional technique.

FIG. 6 is an end view for explaining a case where a flange is formed by another conventional technique.

FIG. 7 is an end view for explaining a state in which wrinkles have occurred in a flange by another conventional technique.

FIG. 8 is an end view for explaining a state in which a crack has occurred at a peripheral edge of a flange by another conventional technique.

FIG. 9 is an end view illustrating a state where a work is simply compressed and deformed like upsetting when an axial force is applied to a relatively thick work by a conventional technique.

[Explanation of symbols]

 W Work Wa End F Flange Fa Peripheral edge Fb Base 10 Die 10a Pressing surface 12 Sleeve 12a Pressing surface 15 Work insertion part 17 Work insertion part 20 Die 22 Sleeve 30 Die 30D Flange pressing part 32 Sleeve 32d Flange pressing part 40 Die 40e recess 40 sleeve 40e recess

Claims (5)

[Claims] 1. A method of forming a flange by pressing a hollow pipe-shaped work in an axial direction to buckle the work, wherein the work is buckled to a predetermined amount while feeding a side of the work where the flange is not formed. A method for forming a flange, comprising: 2. The method according to claim 1, wherein the work buckled to a predetermined amount is further buckled while feeding the work on the side where the flange is formed. 3. A method of forming a flange by pressing a hollow pipe-shaped work in an axial direction to buckle the work, wherein a base end of the work is formed without crushing a distal end of a flange formed on the work. A flange forming method, wherein an axial force is applied so that portions to be contacted with each other. 4. An apparatus for forming a flange by pressing a hollow pipe-shaped work in an axial direction to buckle the work, wherein a pressing member for pressing the work is moved while moving the work on a side of the work where the flange is not formed. A flange forming apparatus characterized in that the pressing surface is inclined so as to bend and the work is allowed to buckle to a predetermined amount. 5. An apparatus for forming a flange by pressing a hollow pipe-shaped work in an axial direction to buckle the work, wherein opposing pressing surfaces of a pressing member for pressing the work are formed by:
A flange forming apparatus characterized in that it is shaped so that stress concentration does not occur at a peripheral end of a flange to be formed.