JP4790136B2 - Hydroform sealing device for thin-walled steel pipes - Google Patents

Description

【００１０】
本発明例では先端樹脂シール部にはポリプロピレンを用いて外径は肉厚ｔ、パイプ径Ｄとすると、Ｄ−２×ｔ−０．３ｍｍとして鋼管との接触しない径を用いた。また、加工用内圧シリンダー用ポート６ａと加工用内圧ポート６ｂは同一受圧面積とした。
従来法ではｔ＝２．０、１．６ｍｍは成形はできたが、ｔ＝０．６、０．８ｍｍの薄肉材は成形水の漏れにより、鋼管が挫屈しまったく拡管成形ができなかった。
樹脂の前方部には更に押さえ金具２ｂの外周部の損傷を防ぐために、テーパー状の金具１０を装着することにより（図４参照）、真円度の悪い薄肉鋼管にも、樹脂シール部の寿命を伸ばすことが可能になる。
【００１１】
また、テーパー状の金具１０は、図１〜３に示すように、押さえ金具２ｂの外径より小さくしても成形用水の圧力により押さえ金具２ｂを介して樹脂シール部２ａのシールを強化する効果も得られるので設置することが好ましい。
更に、図４に示すようにテーパー状の金具１０の外径が、押さえ金具２ｂの外径と実質的に等しい場合でも、テーパー状の金具１０に押さえ金具２ｂに通じる貫通孔を設ければ、同様に押さえ金具２ｂを介して樹脂シール部２ａのシールを強化する効果も得られる。
高圧側の圧力は １５０ＭＰａでも成形水の漏れはみとめられなかった。
【００１２】
【発明の効果】
以上詳述したように、本発明は薄肉管の成形内圧のもれを防止し、安定したハイドロフォームの成形加工を可能とする、シール装置を提供するものとして、工業上有益な効果をもたらし得るものである。
【図面の簡単な説明】
【図１】本発明の実施例である装置の初期状態を説明する断面図である
【図２】本発明の実施例である装置のシール状態を説明する断面図である
【図３】本発明の実施例である装置のシール脱着後の状態を説明する断面図である
【図４】テーパー状の金具を装着した本発明の別の装置を説明する断面図である
【符号の説明】
１ 薄肉鋼管
２ａ 樹脂シール部
２ｂ 押さえ金具
３ 内面シール拡張用シリンダー
４ 高圧ポート
５ 押しこみ具外筒
６ａ 加工用内圧シリンダー用ポート
６ｂ 加工用内圧ポート
７ シリンダー構造ヘッドポート
８ シリンダ構造ロッドポート
９ シリンダーシール冶具
１０管端矯正テーパー冶具[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a sealing device for a hydroform of a thin-walled tube that performs sealing stably from low pressure to high pressure.
The present invention is suitable for hydroform seals for thin-walled steel pipes that cannot be sealed with conventional metal seals having a thickness t = 1.0 mm and a thickness / pipe outer diameter (t / D) = 1.3% or less.
[0002]
[Prior art]
Conventional metal tube hydroform seals are molded using a metal seal or a self-locking seal with a resin attached to the tip.
However, the metal seal is sealed by plastic deformation at the end of the tube due to the pushing force. However, the tube is thin and the tube is buckled, and sealing is impossible. Further, in the case where the resin is attached to the tip, there is a problem that the size of the resin needs to be larger than the inner diameter of the tube, the resin seal is broken at the end surface of the tube, and the number of times of use is small.
In particular, thin-walled steel pipes with wall thickness t = 0.8 mm or less and wall thickness / pipe outer diameter (t / D) <1.3% are hardly subjected to stable hydroforming. It may be said that the area exceeds.
[0003]
[Problems to be solved by the invention]
An object of the present invention is to provide a sealing device that enables hydroforming of a thin-walled tube that cannot be stably processed by a conventional sealing device.
[0004]
[Means for Solving the Problems]
That is, the gist of the present invention is a sealing device for a hydroform for a thin steel pipe having a thickness t = 1.0 mm or less and a thickness / pipe outer diameter (t / D) = 1.3% or less. An inner seal expansion cylinder (3) having a tip protruding from the pusher outer cylinder (5) is provided at the center of the pusher outer cylinder (5), and is provided at the tip of the pusher outer cylinder (5). By pulling in the resin seal portion (2a) surrounding the outer periphery of the inner surface seal expansion cylinder (3) and the inner surface seal expansion cylinder (3), the outer periphery of the resin seal portion (2a) protrudes and the thin wall A presser fitting (2b) having a taper so as to make surface contact with the inner peripheral surface of the steel pipe (1) is installed on the outer periphery of the inner surface seal expansion cylinder in front of the resin seal portion (2a) , and a high pressure is provided. Port (4) is the inner surface A processing internal pressure cylinder port (6a) that penetrates the central axis of the seal expansion cylinder (3) and branches to the pusher outer cylinder (5), and behind the processing internal pressure cylinder port (6a), A hydroform sealing device for a thin-walled steel pipe, characterized in that an internal pressure port (6b) for processing that has the same pressure receiving area or more is disposed .
It is in.
[0005]
DETAILED DESCRIPTION OF THE INVENTION
The present invention will be described in detail.
FIG. 1 is a sectional view of a sealing device according to an embodiment of the present invention.
At the center of the pusher outer cylinder 5 attached to the tip of the push-in cylinder during hydroforming, the inner seal expansion cylinder 3 is held (coaxially), and the inner surface of the thin steel pipe 1 is placed at the tip of the pusher outer cylinder 5. A resin seal portion 2a is provided for contact sealing with the inner surface, and the inner seal expansion cylinder 3 is pulled in, so that the resin seal portion 2a protrudes in the outer peripheral direction and seals the inner surface of the thin-walled steel pipe with a resin. Installed on the outer periphery of the inner surface seal expansion cylinder 3 in front of the seal portion 2a, the molding high pressure port 4 penetrates the central axis of the inner surface seal expansion cylinder 3 and branches into the pusher outer cylinder 5. The cylinder port 6a and the processing internal pressure port 6b are arranged behind the cylinder port 6a so as to have the same pressure receiving area. Pressure and has not changed to the structure.
The resin seal portion 2a needs to have elastic deformability, and it is preferable to use Teflon, polypropylene, polyurethane, PTFE fluororesin, or the like.
[0006]
The reason for providing the processing internal pressure cylinder port 6a and the processing internal pressure port 6b is to prevent the holding force on the drawing cylinder from being affected by sealing with the molding internal pressure, and is injected from the high pressure port 4. The high-pressure molding water passes through the machining internal pressure port 6b and the machining internal pressure cylinder port 6a to the portion sealed by the cylinder seal jig 9 near the tip of the inner surface seal expansion cylinder 3.
[0007]
When the operation is described, the tip of the pusher outer cylinder 5 is inserted into the thin-walled steel pipe 1 and pressure is applied to the cylinder structure rod port 8 so that the inner surface seal expansion cylinder 3 moves backward and the inner surface of the thin-walled steel pipe is tapered. The resin seal portion 2a is stuck in the outer peripheral direction through the holding metal fitting 2b, and is in close contact with the inner surface of the thin steel pipe (FIG. 2).
Thereafter, molding water mixed with an emulsion or a soluble oil is injected into the high-pressure port 4 for molding. Hydroform molding is performed by applying a predetermined amount of indentation with an indentation cylinder.
The seal contact pressure can be controlled by the pressure on the rear cylinder structure rod side.
Further, after the molding pressure is lowered after the processing is finished, the contact can be removed by applying pressure to the cylinder structure head port 7 (FIG. 3). Finally, the resin is obtained by moving the pusher outer cylinder 5. This is a step of removing the seal portion 2a from the steel pipe.
[0008]
The internal pressure cylinder port 6a for branching into the pusher outer cylinder 5 is independent of the high pressure port 4, and the high pressure port 4 passes through the central axis of the inner surface seal expansion cylinder 3, and behind it is a cylinder rod. By disposing the processing internal pressure port 6b having a pressure receiving area equal to or larger than the area, it is possible to take a structure that prevents the seal contact pressure from becoming excessively high due to the cylinder being pulled by the molding pressure.
[0009]
【Example】
Table 1 shows the results of pipe forming hydroform molding into a cylindrical shape molded using the conventional method (comparative example) and the apparatus of the present invention example shown in FIGS.
Pipe outer diameter D = 60.5 mm The wall thickness t indicates the result of tube expansion molding when molding is performed at 0.6 mm, 0.8 mm, 1.6 mm, and 2.0 mm.
Hydroform molding was performed with the indentation amount being 15 mm on each of the left and right axes, and the tube expansion ratio (outer diameter before processing / outer diameter after processing × 100%) being 125%. In the conventional method, a metal seal having the same diameter as the outer diameter of the steel pipe and a groove-like shape was used for the tip jig.
[Table 1]

[0010]
In the example of the present invention, when the outer diameter is the thickness t and the pipe diameter D is used for the tip resin seal portion, the diameter that does not contact the steel pipe is used as D-2 × t-0.3 mm. The internal pressure cylinder port 6a for processing and the internal pressure port 6b for processing have the same pressure receiving area.
In the conventional method, t = 2.0 and 1.6 mm could be formed. However, the thin-walled material with t = 0.6 and 0.8 mm could not be expanded at all because the steel pipe was bent due to leakage of forming water.
In order to prevent damage to the outer peripheral portion of the presser fitting 2b at the front part of the resin, by attaching a taper-shaped metal fitting 10 (see FIG. 4), the life of the resin seal part can also be applied to a thin steel pipe having poor roundness. Can be stretched.
[0011]
In addition, as shown in FIGS. 1 to 3, the taper-shaped metal fitting 10 has an effect of strengthening the seal of the resin seal portion 2 a through the presser metal fitting 2 b by the pressure of the forming water even if it is smaller than the outer diameter of the presser metal fitting 2 b. It is preferable to install it.
Furthermore, as shown in FIG. 4, even when the outer diameter of the tapered metal fitting 10 is substantially equal to the outer diameter of the holding metal fitting 2b, if the through-hole leading to the holding metal fitting 2b is provided in the tapered metal fitting 10b, Similarly, the effect of strengthening the seal of the resin seal portion 2a through the presser fitting 2b is also obtained.
Even when the pressure on the high pressure side was 150 MPa, no leakage of molding water was observed.
[0012]
【The invention's effect】
As described above in detail, the present invention can provide industrially beneficial effects as providing a sealing device that prevents the internal pressure of the thin-walled pipe from leaking and enables stable hydroforming. Is.
[Brief description of the drawings]
FIG. 1 is a cross-sectional view illustrating an initial state of an apparatus according to an embodiment of the present invention. FIG. 2 is a cross-sectional view illustrating a seal state of the apparatus according to an embodiment of the present invention. FIG. 4 is a cross-sectional view for explaining a state of the apparatus according to the embodiment after the seal is detached and attached. FIG. 4 is a cross-sectional view for explaining another apparatus of the present invention equipped with a tapered metal fitting.
DESCRIPTION OF SYMBOLS 1 Thin-walled steel pipe 2a Resin seal part 2b Press fitting 3 Cylinder for expansion of inner surface seal 4 High pressure port 5 Pushing tool outer cylinder 6a Internal pressure cylinder port for processing 6b Internal pressure port for processing 7 Cylinder head port 8 Cylinder structure rod port 9 Cylinder seal Jig 10 Taper Straight Taper Jig

Claims (1)

The center of the pusher outer cylinder (5) in the hydroform sealing device for thin-walled steel pipes with wall thickness t = 1.0 mm or less and wall thickness / pipe outer diameter (t / D) = 1.3% or less An inner seal expansion cylinder (3) having a tip projecting from the pusher outer cylinder (5) is provided at a portion, and the inner seal extension cylinder (3) is disposed at the distal end of the pusher outer cylinder (5). By pulling in the resin seal portion (2a) surrounding the outer periphery and the inner surface seal expansion cylinder (3), the outer periphery of the resin seal portion (2a) protrudes and the inner peripheral surface and surface of the thin steel pipe (1) A presser fitting (2b) tapered so as to make contact is installed on the outer periphery of the cylinder for expanding the inner surface seal in front of the resin seal portion (2a) , and the high pressure port (4) is connected to the inner surface seal extension. Central axis of cylinder (3) A working internal pressure cylinder port (6a) that penetrates and branches into the pusher outer cylinder (5), and a working internal pressure port (behind) that has the same pressure receiving area as the working internal pressure cylinder port (6a) ( 6b) is a hydroform sealing device for thin-walled steel pipes.

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