JPH0321773Y2 - - Google Patents

Description

[Detailed description of the invention] (Field of industrial application) The present invention relates to a tube shrinking device for electric resistance welded steel pipes. This invention relates to a tube constriction device that prevents wavy wrinkles from forming on both sides of a weld bead during tube constriction in the process of constricting the pipe opening.

(Prior art) Conventionally, in order to narrow the end of an ERW steel pipe a that has a weld bead b in the axial direction and perform a tapered pipe contraction as shown in FIG. It was a simple technique in which the end of the tube was pushed in under pressure. However, since the weld bead b of the ERW steel pipe a has a high hardness, there is a hardness and softness difference between the bead b and both sides thereof, which has a different sensitivity to compression pressure. Therefore, when performing the above-mentioned narrowing and contraction after expanding the diameter, the difference in hardness and softness between the weld bead b and the steel on both sides increases, so noticeable wrinkles d are created as shown in Fig. 9. There are drawbacks that arise.

(Problems to be Solved by the Present Invention) In view of the above, an object of the present invention is to develop a tube shrinking device that performs drawing forming without causing wrinkles on both sides of a weld bead.

(Means for Solving the Problems) The present invention aims to solve the above-mentioned problems, and specifically, it is an electric resistance welded steel pipe 21 and a fixed shaft 2 that fits into the pipe end opening 24 of the pipe 21. The fixing shaft 2 is formed with a protruding inclined pipe shrinking surface 3 that matches the inner surface shape of the end shrink pipe of the electric resistance welded steel pipe, and can be caused to escape from the end of the shrink pipe. Slanted tube reduction surface 3 to minimize the area
Wrinkle prevention type 1 made by cutting and removing 5 on a part of
and a movable tube contraction mold 7 having a circular diameter reduction mold surface 8 that is in close contact with the inclined tube contraction surface 3 of the anti-wrinkle mold 1 through an electric resistance welded steel pipe 21. This apparatus is characterized in that the weld bead and both sides of the weld bead are pressurized by an inclined pipe shrinking surface 3 and a diameter reducing mold surface 8 to prevent wrinkles from forming.

A preferred embodiment of the invention will be described in the following section.

(Embodiment) Figures 1 to 7 of the accompanying drawings show an embodiment of the present invention,
Fig. 1 is a perspective view of the anti-wrinkle mold 1 of the present invention, Fig. 2 -
FIG. 6 is a partially cutaway side view showing the use of the tube shrinking device of the present invention according to the working order, and FIG. 7 is a perspective view of the tube shrinking product.

Reference numeral 21 is an electric resistance welded steel pipe with an axial weld bead 22, which has been expanded in diameter 23 at its end using a diameter expanding device in the previous process, and has a tapered shape formed on the outer periphery of its opening 24 at the end. This produces a constricted tube 25 as shown in FIG.

1 shows a wrinkle-preventing type that corresponds to the pipe end opening 24 of the ERW steel pipe 21, and the outer diameter almost matches the inner diameter D (see Fig. 7) of the ERW steel pipe 21 to be shrunk. A fixed shaft 2 having a diameter is provided with an inverted conical inclined diameter-reducing surface 3 protruding from its distal end, and a shaft portion 4 extending in the axial direction from the large-diameter outer end of the diameter-reducing surface 3 is provided. In order to make it possible to escape from the reduced tube inner diameter D as shown in FIG.
The anti-wrinkle mold 1 has a structure in which the cross-sectional area of the tip surface is reduced. (Figure 1).

The electric resistance welded steel pipe 21 is supplied to the anti-wrinkle mold 1 as shown in FIG. Grasp and fix the pipe portion that is not provided with the diameter 23. A movable diameter reducing die 7 is fitted onto the outer periphery of the shaft fixing shaft 2 of the anti-wrinkle die 1 so as to be freely slidable. The movable diameter reducing type 7 has an electric resistance welded steel pipe 2.
A circular diameter reducing mold surface 8 is provided which is partially in close contact with the inclined diameter reducing surface 3 through the diameter reducing mold surface 8.
A sliding hole 10 is provided from the inner diameter end 9 in contact with the outer periphery of the fixed shaft 2, and the sliding hole 10 is movably brought into close contact with the fixed shaft 2, and a fitting hole 11 connected to the large diameter portion of the reduced diameter mold surface 8 is provided. establish. The fitting hole 11 has a structure in which the tube end opening 24 of the electric resistance welded steel tube 21 is fitted into the fitting hole 11 as shown in FIG.

In this embodiment, the chucks 6 and 6a are opened as shown in Fig. 2, and the movable diameter reducing die 7 is moved to the left as shown in the figure by the cylinder rod 12, so that the anti-wrinkle die 1 is relatively protruded. state, ERW steel pipe 2
1 is supplied to the prevention mold 1 from the tube end opening 24, and the third
As shown in the figure, the opening 24 is fitted onto the shaft portion 4 remaining after cutting and removal 5, and the opening 24 is fitted onto the inner periphery of the fitting hole 11 of the movable diameter reducing die 7, and at the same time the chucks 6, 6a are fitted.
The electric resistance welded steel pipe 21 is grasped by the cylinder rod 12, and the movable diameter reduction mold is moved to the right as shown in FIG.
A tapered tube contraction 25 shown in FIG. 7 is produced by pressing against the outer circumferential surface of the tube, and a part of the mold surface 8 is pressed against the wrinkle-preventing inclined tube contraction surface 3 via the steel pipe 21.

The electric resistance welded steel pipe 21 has the outer surface of the pipe end opening 24 formed into a tapered reduced pipe 25 as shown in FIG.
The weld bead passing through a part of the shrink tube 25 and both sides thereof are sandwiched and pressurized by the diameter reducing mold surface 8 and the inclined tube shrinking surface 3 of the anti-wrinkle mold 1, as shown in FIG. Wrinkles d as shown do not occur at all.

After the diameter reduction work of the ERW steel pipe 21 is completed, the movable diameter reduction mold 7 is returned to the starting position shown in FIG. 2 by the cylinder rod 12, and the chucks 6 and 6a are opened as shown in FIG. The shaft 4 and inclined diameter reducing surface 3 of the anti-wrinkle mold 1 are relatively removed from the inner diameter D of the reduced tube narrowed by 25 to obtain the product shown in FIG.

(Functions and Effects) The present invention forms the tapered tube shrinkage shown in FIG. 7 of the tube end opening 24 of the electric resistance welded steel pipe 21 by forcibly pressing it against the conventional tube shrinkage type C illustrated in FIG. Rather, a fixed shaft 2 is formed to protrude from the fixed shaft 2 that moves relatively to the pipe end 24 of the ERW steel pipe 21 so that the outer periphery matches the inner surface of the contracted pipe shape, and a part is formed so that it can relatively escape from the mouth of the contracted pipe. Cut and remove 5
It consists of a wrinkle-preventing die 1 which has been subjected to Since the weld bead 22 and both sides thereof are sandwiched and pressurized between a part of the surface 8 and the inclined constriction surface 3 of the wrinkle prevention mold 1, the weld bead 22 of the tapered constriction tube 25 and its The wrinkles shown in Fig. 9 due to the hardness and softness of the steel on both sides do not occur at all. In addition, since the inclined shrinking surface 3 of the anti-wrinkle type 1 is cut and removed 5 in an area that can be relatively removed from the mouth of the tapered shrinking pipe 25 of the steel pipe 21, pipe shrinking of the electric resistance welded steel pipe 21 is performed. There is no problem in removing the relative escape later, and it has the effect of constructing a tube shrinking device that can extremely easily prevent the occurrence of wrinkles near the weld bead.

[Brief explanation of the drawing]

Figures 1 to 7 illustrate embodiments of the present invention, in which Figure 1 is a perspective view of the anti-wrinkle mold 1, and Figures 2 to 6 are partially cutaway side views sequentially showing operating modes of the device of the present invention. FIG. 7 is a perspective view of the diameter-reduced product. 8th
The figure is a cross-sectional view of a conventional tube shrinking tool, and Figure 9 is a bead b.
FIG. 2 is a perspective view of wrinkles that occur near 1...Wrinkle prevention type, 2...Fixed shaft, 3...
... Inclined pipe reduction surface, 5 ... Cutting and removal, 6, 6a ... Chick, 7 ... Moving diameter reduction type, 8 ... Diameter reduction type surface, 1
2... Cylinder rod, 21... ERW steel pipe, 22
... Weld bead, 23 ... Diameter expansion, 24 ... Tube end opening, 25 ... Tapered pipe contraction.

Claims (1)

[Scope of utility model registration request] The electric resistance welded steel pipe 21 and the fixed shaft 2 fitted into the pipe end opening 24 of the electric resistance welded steel pipe 21 are provided so as to be free to move relative to each other, and the fixed shaft 2 is provided with an inclined constriction that matches the inner surface shape of the tapered constriction tube 25 of the electric resistance welded steel pipe 21. Wrinkle-preventing mold 1 formed by projecting the tube surface 3 and cutting and removing a part of the inclined tube surface 3 in order to create an area that allows the tube surface 3 to escape from the end port 24 of the tube tube 25.
and a movable tube contraction die 7 having a circular diameter reduction die surface 8 that is partially in close contact with the inclined tube contraction surface 3 of the anti-wrinkle die 1 via the electric resistance welded steel pipe 21. Steel pipe 21
A pipe shrinking device for an electric resistance welded steel pipe, characterized in that the pipe shrinks the steel pipe 21 and pressurizes the weld bead 22 of the steel pipe 21 and both sides thereof by an inclined pipe shrinking surface 3 and a diameter reducing die surface 8.