JPH0790270B2 - Metal pipe forming method - Google Patents

Description

TECHNICAL FIELD The present invention relates to a metal pipe forming method.

[Prior Art] The metal pipe forming method includes a roll forming method and a die forming method. The roll forming method is shown in FIGS. 3 (a) and 3 (b). As shown in the figure, the roll forming method forms a metal pipe by the roller 2 driven by the driving unit 1, but this method is expensive because the structure of the driving unit 1 and the like is complicated.

FIG. 4 shows a molding die of a die molding system. Although such a method using the molding die 3 is inexpensive, it is difficult to obtain accuracy because abrasion scratches or the like occur. The shape of the final molding die is a circle or a two-division circle, and high-density polyethylene is used as the die material.

[Problems to be Solved by the Invention] The above-mentioned conventional technology has the following problems.
(1) To prevent damage to the outer circumference of the metal pipe, use cross-linked polyethylene or the like as the material of the molding die, but the hardness is small and a part of the die corresponding to the metal tape abutment part wears and wear powder of the die Burning occurs in the welding torch, making uniform pipe welding difficult. (2) Since the molding die wears, its life is short and it takes time to replace the molding die.
(3) When cemented carbide or hardened steel is used as the material of the forming die, the life is extended, but friction scratches occur on the surface of the formed metal pipe. (4) Stable manufacturing work is difficult. (5) Since the inner diameter of the forming die is fixed, the gap between the outer diameter of the formed metal pipe and the inner diameter of the forming die cannot be adjusted.
(6) If the inner diameter of the final stage forming die and the outer diameter of the formed metal pipe are not in a proper relationship, the metal tape abutting portion will have a shape as shown in FIGS. 5 (a) and 5 (b). . That is, a gap is generated at the abutting portion a of the formed metal pipe 4.

The present invention has been made in view of the above points, and an object thereof is to provide a metal pipe molding method capable of facilitating uniform joining work of metal pipes while using a molding die. is there.

[Means for Solving Problems] The above-mentioned object is to provide a notch in a part of the circumference of a forming die of a forming tool, and to provide the notch of the forming die with a curvature of an outer diameter of a metal pipe to be formed. This is achieved by providing a slug-shaped rotating roll having the same radius of curvature as the radius and movable in the radial direction, and contacting the slug-shaped rotating roll with a portion of the abutting portion of the metal pipe.

[Operation] In the present invention, a notch is provided on a part of the circumference of the forming die of the forming tool, and the butt-shaped rotary roll provided in the notch of the forming die is movable in the radial direction so that Not only does it prevent deformation, it also has low frictional resistance and does not cause scratches. Carbide rolls and quenching rolls can be used, which has a long life and a part of the rotating rolls wear out to generate abrasion powder. As a result, it is possible to facilitate the uniform joining work of the abutting portions of the metal pipes. That is, in the final stage forming die, a super hard roll and a squeezing type rotary roll using a quenching roll are formed at the abutting portion of the metal pipe, and a part thereof is worn to generate die abrasion powder. And the joining work of the abutting portions of the metal pipes becomes easy.

[Examples] Hereinafter, the present invention will be described based on illustrated examples. An embodiment of the present invention is shown in FIGS.
Since the same parts as those of the conventional one are designated by the same reference numerals, the description thereof will be omitted. As shown in FIG.
The metal tape is molded with 9 and the metal pipe 4 is molded by abutting in a pipe shape. In this embodiment, the final-stage forming die 10 of the forming tool 9 in the final stage is formed on a part of the circumference of the forming die 10. A notch is provided, and a notch-shaped rotary roll 11 that has the same radius of curvature as the outer radius of the metal pipe 4 to be formed and is movable in the radial direction is provided in the notch of the forming die 10. did. By doing so, a uniform joining operation of the metal pipes 4 is facilitated, and a metal pipe molding method capable of facilitating the uniform joining operations of the metal pipes 4 can be obtained.

That is, a notch is provided on a part of the circumference of the forming die 10, and the claw-shaped rotating roll 11 is provided at the notch of the forming die 10.The claw-shaped rotating roll 11 is provided with a screw 12, a presser 13
It was attached to the pin 14 with a bearing 15 interposed. By doing so, the metal tape is sequentially formed into a pipe shape, but the butted portion a of the pipe-shaped metal pipe 4 has a knurled shape having a radius of curvature equal to the outer diameter of the metal pipe 4. The roll 11 is pressed down and positioned so as not to deform the butt portion a. At this time, the claw-shaped rotating roll 11 is pushed up by the spring force of the metal pipe 4. Therefore, the pin 14 tends to deform, but since the screw 12 and the presser 13 are installed to prevent this deformation, the deformation is prevented and the concentric metal pipe 4 is formed. Since the claw-shaped rotating roll 11 is not worn, no scratches are generated, and since a cemented carbide roll or a quenching roll can be used, it has a long life and works.

As described above, according to this embodiment, the following operational effects can be obtained.

(1) Abrasion powder of the final stage forming die is not generated, and uniform joining work is easy. (2) The replacement work of the final-stage molding die is unnecessary. (3) There is no fear of friction scratches due to the rotating roll. (4) Safety work can be easily performed, and abrasion powder is not generated even for a cable exterior, so that defective products can be drastically reduced.

It should be noted that the abrasion resistance can be reduced by using a combination of three 120 ° rotary rolls or 90 ° four rotary rolls, and the rolls can be used for other locations.

EFFECTS OF THE INVENTION As described above, the present invention makes it possible to obtain a metal pipe molding method that facilitates uniform joining of metal pipes and facilitates uniform joining of metal pipes. .

[Brief description of drawings]

FIG. 1 is a partial cross-sectional view of a final stage forming die according to an embodiment of the metal pipe forming method of the present invention, and FIG. 2 is an overall explanatory view showing a forming state by a forming tool of the same embodiment, FIG. (A) and (b) show the forming roll and the drive part by the roll forming method of the conventional metal pipe forming method.
Is a front view, (b) is a side view, and FIG. 4 is a sectional view of a forming die by a die forming method of a conventional metal pipe forming method,
FIGS. 5 (a) and 5 (b) show a state in which a gap is generated at the abutting portion of the metal pipe by the die forming method of the conventional metal pipe forming method, and FIG. (B) is a front view showing a state in which a gap is generated in the lower portion. 4: Metal pipe, 5-9: Forming tool, 10: Final stage forming die, 11: Catch type rotatable roll, 12: Screw, 13: Presser, 14: Pin, 15: Bearing.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (56) References JP-A-61-253116 (JP, A) Actually opened 58-13808 (JP, U) Actually opened 60-60167 (JP, U)

Claims (2)

[Claims] 1. A metal tape is molded with a molding tool having a plurality of stages,
In a metal pipe forming method of forming a metal pipe by abutting in a pipe shape, a notch is provided in a part of the circumference of a forming die of the forming tool, and the notch of the forming die forms a metal pipe to be formed. A zigzag rotation roll having the same radius of curvature as the outer diameter and movable in the radial direction is provided, and the zigzag rotation roll is brought into contact with the abutting portion of the metal pipe. And a method for forming a metal pipe. 2. The method for forming a metal pipe according to claim 1, wherein the hook-shaped rotary roll is provided on a pin having a screw and a presser via a bearing.