JP2000046260A - Thin-walled pipe with waveform screw - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a thin-walled pipe with a waveform screw to perform proper pipe joining through simple structure without needing a pipe coupling for exclusive use. SOLUTION: A thin-walled pipe 1a with a waveform screw is a straight pipe, the straight pipe having a taper male screw (a spigot shape) 3a having a whole thickness in a waveform helical shape formed on the outer surface of one pipe end of a thin-walled pipe body 2a and a taper female screw (a bell shape) 4a with a whole thickness in a waveform helical shape formed on the inner surface of the other pipe end. Since the thin-walled pipe 1a with a waveform screw has the taper male screw 3a having a whole thickness in a waveform helical shape and the female screw 4a having a whole thickness in a waveform helical shape, the effective pipe thicknesses of the taper male screw 3a and the taper female screw 4a are approximately equal to that of other part of the thin-walled pipe body 2a and the strength of the thin-walled pipe 1a with a waveform screw is held. Manufacture of a screw at the pipe end part of the thin-walled pipe body 2a by a form rolling work is facilitated.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a thin tube with a corrugated thread used for connecting a metal tube, a resin tube, a composite material tube, a composite structure tube and the like.

[0002]

2. Description of the Related Art Generally, parallel threads (JIS B020) are used for connecting metal pipes, resin pipes, composite material pipes, composite structure pipes, and the like.
2), taper screws (JIS B0203) and the like are used. Here, the pipe body has a parallel male thread or a taper male thread on the outer surfaces of both pipe ends, and is screw-connected to a pipe threaded joint having a parallel female thread or a taper female thread on the inner surface.
The parallel thread and the taper thread as described above are generally manufactured by thread cutting or thread rolling.

However, such metal pipes, resin pipes, composite material pipes, composite structure pipes and the like are often used as thin-walled pipes. The rate of decrease in the effective pipe thickness at the thread bottom is large, and the joint strength is significantly reduced. Further, it cannot be applied to a thin-walled tube having a tube thickness smaller than the thread height specified by JIS or the like.

[0004] In a thin-walled tube, cutting is difficult due to a decrease in rigidity at the end of the tube, and the accuracy of the thread is liable to be reduced.

On the other hand, when a screw is manufactured at the pipe end of a thin-walled pipe by rolling, it is difficult to manufacture a thread or the like specified by JIS by rolling at a thin-walled pipe due to a decrease in the rigidity of the pipe end. Therefore, non-axially symmetric deformation of the cross section of the screw portion and defective thread are likely to occur.

For this purpose, various measures have been studied for a threaded joint for thin-walled pipes. For example, Japanese Unexamined Utility Model Publication No. 4-117983 discloses a jointed structure for thin-walled stainless steel pipes.

In the above technique, a thin stainless steel pipe and a joined body are provided with corrugated spiral undulations to be screw-fitted, a packing is attached between the pipe end and the joined body, and a thin stainless steel pipe is attached to the joined body end. When the protrusion attached to is screwed in,
Holes and cuts are added to prevent loosening of the tube and rotation withdrawal.

[0008] According to the present technology, it is possible to solve the drawback that the thread for cutting the pipe main body was short, and the threaded joint could not be used.

[0009]

However, the technique disclosed in Japanese Utility Model Laid-Open Publication No. 4-117983 is a so-called corrugated spiral parallel threaded joint, in which the pipe is loosened and screwed out after screw fitting. It is necessary to attach a projection to the thin-walled stainless steel pipe to prevent this, and to add a hole at the end of the joined body that fits when the projection is screwed and a notch that allows the projection to advance. And the threaded joint structure is complicated, and its manufacture is complicated.

An object of the present invention is to solve the above-mentioned problems and to provide a thin tube with a corrugated thread which can be appropriately joined with a simple structure.

[0011]

According to a first aspect of the present invention, a thin-walled pipe body has a tapered external thread having a wavy spiral shape on the outer surface of one end of the pipe, and a full thickness on the inner surface of the other end. A thin tube with a corrugated thread, comprising a female thread having a corrugated spiral shape.

According to a second aspect of the present invention, a thin-walled tube body has a tapered external thread having a wavy spiral shape on the outer surface of one end of the tube, a bent portion provided on the other end of the tube, and an inner surface at the tip of the bent portion. A thin tube with a corrugated thread characterized by having a female thread with a corrugated spiral shape in its entire thickness.

According to a third aspect of the present invention, in the first aspect or the second aspect, the entire thickness provided on the outer surface of the one end of the thin-walled tubular main body follows the tapered male thread having a wavy spiral shape. A thin tube with a corrugated thread, comprising one or a plurality of corrugated portions on the outer surface parallel portion.

According to the present invention, since the thin-walled tubes are directly and reliably joined to each other, the working efficiency can be greatly improved.

[0015]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments of the present invention will be described below in detail with reference to the drawings.

FIG. 1 is a side view showing an embodiment of the present invention, FIG. 2 is an enlarged sectional view of a main part indicated by reference numeral A in FIG. 1, and FIG. 3 is a main part indicated by reference numeral B in FIG. It is an expanded sectional view.

The thin-walled tube 1a having a corrugated thread has a tapered male screw (spigot shape) 3a having a corrugated spiral shape as shown in FIG. 2 on the outer surface of one tube end of the thin-walled tube main body 2a, and the other tube end. 3 is a straight pipe having a tapered internal thread (bell shape) 4a having a wavy spiral shape on the inner surface as shown in FIG.

As described above, the corrugated threaded thin tube 1a is provided with a corrugated spiral tapered male screw 3a and a corrugated spiral tapered female screw 4a at the end of the thin tube main body 2a. As a result, the effective tube thickness of the tapered male screw 3a and the tapered female screw 4a is substantially equal to other portions of the thin-walled tube main body 2a, and the strength of the thin-walled tube 1a with a corrugated thread can be maintained.

Since the thin tube 1a with a corrugated thread has the above-described structure, it is easy to manufacture a screw at the tube end of the thin tube main body 2a by rolling. Also, a thin-walled tube 1a with a corrugated thread
Is extremely thin or very soft material, a filler such as solid rubber or a cylindrical support metal is inserted into the thin-walled tube main body 2a to increase the rigidity of the threaded portion against external working force, and the predetermined thread shape is increased. To be obtained. The male thread of the thin-walled tube main body 2a can be produced not only by rolling but also by pressing.

Although the total length of the thin-walled pipe main body 2a used in the present invention is arbitrary, the prefabricated pipe has an effective length which is the length of a component in a building piping diagram.
5,000 mm or the like is used as a fixed size. The effective length is a value obtained by subtracting the screw engagement length from the entire length of the thin-walled tube main body.

Further, the present invention provides a comparison between a pipe steel pipe, a pipe for heat transfer, a steel pipe for structural use, a steel pipe for special use, and an alloy pipe which are JIS pipe materials having a small absolute value of a pipe thickness or a pipe diameter. It is applied to a tube having a relatively thin wall.
For example, stainless steel pipes for general piping (JISG344
8) and carbon steel tubes for general structures (JIS G3444). Further, the present invention is also applied to a pipe having a relatively small thickness such as a pipe made of a nonferrous metal material, a copper alloy pipe, an aluminum pipe, and an aluminum alloy pipe, and various resin pipes made of a nonmetallic material. Furthermore, it is also effective for specially-designed ultra-thin tubes that are made thinner than the JIS tube thickness.

FIGS. 2 and 3 show a shallow groove type (thread height h).
Thin pipe 1 with a corrugated thread whose thread size is smaller than the pipe thickness t)
a.

As shown in FIG. 2, a thin tube 1a with a corrugated thread
The thin-walled pipe main body 2a is provided with a shallow grooved tapered external thread 3a at one end of the pipe, and the height h of the thread of the shallow grooved tapered external thread 3a is smaller than the pipe thickness t (t> h). ) Screw dimensions.

The height h of the thread is (the outer diameter D−the diameter d of the valley) / 2 at the end of the thin-walled tube main body 2a having the tapered male screw 3a.
Is the average height of In the effective length L of the thread portion, three threads with a thread pitch P are manufactured so as to reduce the diameter toward the pipe tip with a taper 1/16 (diameter) as shown by a taper line M indicated by a two-dot chain line. I have.

Here, using the center axis S of the tube axis indicated by a dashed line, it is assumed that the tube end of the cross-sectional shape has a tapered shape narrowed axially symmetrically with respect to the center line S with respect to the tube axis center line S. It clearly shows.

The thread waveform is a continuous arc or sinusoidal curve. There is no reduction in pipe thickness due to threading over the entire threaded portion.

On the other hand, as shown in FIG. 3, the threaded tapered female thread 4a is formed in a tapered shape widened in the pipe end direction as shown by a tapered line M, and as shown in FIG.
The tapered male thread (the same as the tapered male thread 3a) of the thin pipe with a corrugated thread to be joined can be threadedly joined. Here, using the tube axis center line S indicated by a dashed line, it is clearly shown that the tube end of the cross-sectional shape is tapered so as to be axially symmetric with respect to the tube axis center line S and widened toward the tube end. I have.

FIG. 4 is a view showing an example of a threaded state of the thin tube with a corrugated thread according to the present invention. A tapered male screw 3a provided at the end of the thin tube main body 2a of the thin tube 1a with a corrugated thread and a female taper 4b provided at the end of the thin tube main body 2b of the thin tube 1b with a corrugated screw are screwed. ing. Because of the tapered shape, the tube end of the corrugated threaded thin tube 1a is inserted into the tube end of the corrugated threaded thin tube 1b and is brought into contact with the tube for relative rotation of the corrugated threaded thin tube 1a and the corrugated screw thin tube 1b. Is generated, the thin tube 1a with a corrugated thread and the thin tube 1b with a corrugated thread are screwed together by the meshing of the screws accompanying the tightening. The pitch and taper of the taper male screw and the taper female screw are the same, and in the screw connection of the pipes, the pipes are relatively rotated with a predetermined number of threads or a tightening torque, and the tightening is completed at the position of the reference diameter.

The number of threads and the pitch of the screw are not limited to the number of threads and the pitch in FIG. 4, but can be determined as appropriate.

FIG. 5 is an enlarged sectional view of a main part showing another embodiment according to the present invention. Here, a thin groove type pipe 1c with a corrugated thread of a deep groove type (thread height h is equal to or larger than the pipe thickness t) is shown.

As shown in FIG. 5, the deep groove type tapered male screw 3
c is a thread size in which the thread height h is equal to or greater than the pipe thickness t (t ≦ h). The height h of the thread is an average height of (outer diameter D−diameter d of root) / 2 of the pipe end of the thin-walled pipe main body 2c having the tapered male screw 3c.

In the effective length L of the thread portion, three threads with a thread pitch P are manufactured such that the diameter of the thread is reduced toward the tip of the pipe by a taper 1/16 (diameter) as shown by a taper line N. . Here, using the pipe axis center line S indicated by a dashed line, it is clearly shown that the pipe end of the cross-sectional shape is tapered in the axial direction symmetrically with respect to the pipe axis center line S in the pipe end direction. ing.

The waveform of the thread is a continuous arc or sinusoidal curve. There is no reduction in pipe thickness due to threading over the entire threaded portion.

Next, the case where the thin tube with a corrugated thread of the present invention has a bent portion at one end of the tube will be described.

FIG. 6 is a side view having a partial cross section showing another embodiment of the present invention. As shown in FIG. 6, a thin tube 1d with a corrugated thread is provided with a bent portion 5 at one tube end of a thin tube main body 2d, and a tapered female screw 4d having a corrugated spiral shape with a full thickness is formed on the inner surface of the bent portion. Have. Here, a tapered male screw 3e provided at one end of the thin tube main body 2e of the thin tube 1e with a corrugated thread is inserted into the tapered female screw 4d,
Screwed. Straight pipe part 6 of thin pipe 1d with corrugated thread
On the outer surface of the tube end (not shown), the same thickness as the tapered male screw 3e has a wavy spiral tapered male screw.

Tapered female thread 4d of thin pipe 1d with corrugated thread
And the tapered male thread 3e of the corrugated threaded thin tube 1e is tapered as shown by the tapered line Q, so that the tube end of the corrugated threaded thin tube 1e is the tube end of the corrugated threaded thin tube 1d. When the thin tube with corrugated thread 1e and the thin tube with corrugated thread 1d are caused to rotate relative to each other, the thin tube with corrugated thread 1d and the thin tube with corrugated thread 1e are engaged with each other by the engagement of the screws accompanying the tightening. Screw connection.

Here, the pipe axis center line S indicated by a dashed line is clearly used to clearly show that the pipe end of the sectional shape is tapered toward the pipe end with respect to the pipe axis center line S. .

FIG. 7 is a side view with a partial cross section showing another example of a bent state of the thin tube with a corrugated thread constituting the present invention.

Parts common to FIG. 6 are given the same reference numerals,
The description is omitted. In FIG. 7, a thin pipe 1d with a corrugated thread is formed by bending a pipe end 6a of a straight pipe portion 6 at a predetermined angle and welding and joining a short pipe 7 having a female tapered thread 4d. Symbol Q is a tapered line. The tapered female thread 4d of the thin pipe 1e with a corrugated thread is inserted into the tapered female thread 4d of the welded short pipe 7 and screwed. Reference numeral 8 denotes a weld. Here, the tube axis center line S indicated by a dashed line is clearly used to clearly show that the tube end of the cross-sectional shape is tapered toward the tube end with respect to the tube axis center line S.

Since the short pipe 7 having the female tapered thread 4d is welded and united, the thin pipe 1d with a corrugated thread can be easily manufactured.

FIG. 8 is a side view with a partial cross section showing another example of the bent state of the thin tube with a corrugated thread constituting the present invention. 6 and 7 are denoted by the same reference numerals, and description thereof is omitted.

In FIG. 8, a thin tube 1 d having a corrugated thread is provided with a bent portion by welding a bent tube 9 having a predetermined angle to a tube end 6 b of a straight tube portion 6. The short pipe 7 having the female tapered thread 4d is welded and integrated. Symbol Q is a tapered line. The tapered female thread 4d of the thin pipe 1e with a corrugated thread is inserted into the tapered female thread 4d of the welded short pipe 7 and screwed. Reference numeral 8 denotes a weld.

Here, using the tube axis center line S indicated by a dashed line, it is clearly shown that the tube end of the cross-sectional shape is tapered toward the tube end with respect to the tube axis center line S. .

Since the short pipe 7 having the tapered internal thread 4d is welded and integrated through the bent pipe 9, the manufacture of the thin pipe 1d with a corrugated thread is further facilitated.

FIG. 9 is a sectional side view of a main part showing another embodiment of the present invention. As shown in FIG. 9, the thin tube 1f with a corrugated thread has a tapered male screw 3f whose entire thickness is a corrugated spiral on the outer surface of the tube end of the thin tube main body 2f. Symbol O is a tapered line. A waveform 11 is provided on the outer surface parallel portion 10 of the thin-walled tube main body 2f following the tapered male screw 3f. The number of waveforms 11 is 1
More than one can be determined as appropriate. Generally, 2 to 5 pieces are provided. Here, using the tube axis center line S indicated by a dashed line, it is clearly shown that the tube end of the cross-sectional shape is tapered in the tube end direction with respect to the tube axis center line S.
When the thin tube with a corrugated thread is subjected to external force after being piped with a thin tube with a corrugated screw (not shown) by screw connection, the external force can be absorbed and the influence on the piping can be reduced.

The corrugated portion 11 can be easily provided by using the same processing apparatus when manufacturing the tapered male screw 3f.

FIGS. 1 to 9 show the case where the corrugated spiral tapered male thread of the corrugated threaded thin tube and the tapered female thread of the corrugated threaded thin tube are screw-fitted. By providing a lining material on the surface of the tape to provide corrosion protection, or by arranging a sealing material between the tapered male screw and the tapered female screw, the sealing property can be further improved. As the sealing material, a liquid sealing material, a tape-shaped sealing material, or the like can be arranged on site, and a sealing material such as a rubber system can be arranged in advance at a factory on a tapered male screw.
In addition, a thin pipe with a corrugated thread formed of a straight pipe and a thin pipe with a corrugated thread having a bent portion can be appropriately combined and screwed.

As shown in the above embodiments, a dedicated pipe joint is not required, and the pipes can be joined by a single screwing operation, so that the working efficiency is high. In addition, with respect to applied loads such as tension, compression and bending acting on piping,
Since the joint is not deformed or broken, and the sealing property is maintained, the strength of the material that the pipe body originally has can be sufficiently exhibited as the entire pipe. Furthermore,
Since the thread shape is curved, stress concentration to tension and bending loads of the pipe body can be reduced, so even under repeated loads, fatigue cracks do not occur from this part first, ensuring pipe strength it can.

Further, since there is almost no decrease in the effective pipe thickness in the thread processing, the decrease in the pipe strength due to the decrease in the pipe thickness of the thin-walled pipe is small. Forming with a commercially available pipe thread rolling machine is possible and applicable to on-site construction. Since the molding force is small, it can be applied to a pipe made of a soft material.

Further, the pitch of the corrugated thread is considerably larger than that of the tapered thread for pipes of JIS, and the predetermined tightening is completed with a small amount of rotation, so that the working efficiency is improved.

[0051]

According to the present invention, a thin-walled pipe can be joined without requiring a special pipe joint, and its manufacture is easy.

[Brief description of the drawings]

FIG. 1 is a side sectional view showing an embodiment of the present invention.

FIG. 2 is an enlarged sectional view of a main part indicated by reference numeral A in FIG.

FIG. 3 is an enlarged sectional view of a main part indicated by reference numeral B in FIG.

FIG. 4 is a view showing an example of a thread-joined state of a thin tube with a corrugated thread of the present invention.

FIG. 5 is an enlarged sectional view of a main part showing another embodiment according to the present invention.

FIG. 6 is a side view with a partial cross section showing another example of the bent portion state of the thin tube with a corrugated thread constituting the present invention.

FIG. 7 is a side view with a partial cross section showing another example of the bent state of the thin tube with a corrugated thread that constitutes the present invention.

FIG. 8 is a side view with a partial cross section showing another example of a bent state of the thin tube with a corrugated thread which constitutes the present invention.

FIG. 9 is a sectional side view of a main part showing another embodiment of the present invention.

[Explanation of symbols]

1a-1f Thin pipe with corrugated thread 2a-2f Thin pipe main body 3a, 3c, 3e, 3f Tapered male thread 4a, 4b, 4d, 4e, 4f, 4g, 4h Female taper thread 5 Bent part 6, 6a, 6b Straight pipe Part 7 short pipe 8 welded part 9 bent pipe 10 straight pipe parallel part 11 waveform

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Akihiko Kato 1-2-1, Marunouchi, Chiyoda-ku, Tokyo Nihon Kokan Co., Ltd. (72) Nobuhisa Suzuki 1-2-1, Marunouchi, Chiyoda-ku, Tokyo Sun F-term in Honko Tube Co., Ltd. (reference) 3H013 GA08

Claims (3)

[Claims] 1. A thin-walled pipe main body having a tapered male thread having a wavy spiral shape on the outer surface of one end of the tube and a female screw having a wavy spiral shape on the inner surface of the other end. A thin-walled tube with a corrugated thread, comprising: 2. A thin-walled tube main body has a tapered male screw having a wavy spiral shape on the outer surface of one end of the tube end, a bent portion provided on the other end of the tube, and a full thickness on the inner surface of the tip end of the bent portion. Has a corrugated spiral tapered female thread. 3. A thin-walled tube main body having one or more corrugated portions provided on the outer surface of one end of the tube at a portion parallel to the outer surface of the tube following a tapered male thread having a corrugated spiral shape. The thin tube with a corrugated thread according to claim 1 or 2,