JP6822462B2 - Threaded joint of steel pipe - Google Patents
Threaded joint of steel pipe Download PDFInfo
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- JP6822462B2 JP6822462B2 JP2018236952A JP2018236952A JP6822462B2 JP 6822462 B2 JP6822462 B2 JP 6822462B2 JP 2018236952 A JP2018236952 A JP 2018236952A JP 2018236952 A JP2018236952 A JP 2018236952A JP 6822462 B2 JP6822462 B2 JP 6822462B2
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- 229910000831 Steel Inorganic materials 0.000 title claims description 49
- 239000010959 steel Substances 0.000 title claims description 49
- 238000005520 cutting process Methods 0.000 claims description 9
- 238000010276 construction Methods 0.000 description 6
- 238000000034 method Methods 0.000 description 6
- 238000005242 forging Methods 0.000 description 3
- 230000013011 mating Effects 0.000 description 2
- 230000015572 biosynthetic process Effects 0.000 description 1
- 230000003247 decreasing effect Effects 0.000 description 1
- 230000006866 deterioration Effects 0.000 description 1
- 230000000694 effects Effects 0.000 description 1
- 230000002265 prevention Effects 0.000 description 1
- 238000003466 welding Methods 0.000 description 1
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Description
本発明は、構造物の支持をする鋼管の端部に取り付けられて鋼管同士を接続する鋼管のねじ継手に関する。 The present invention relates to a threaded joint of a steel pipe attached to an end of a steel pipe that supports a structure and connects the steel pipes to each other.
鋼管のねじ継手は複数の鋼管を接続するために広く使われており、例えば構造物の基礎や地滑りの抑止などに利用される鋼管杭を構成する鋼管の接続に用いられる。このような鋼管杭は、施工の条件により必要な長さが数十ｍに及び、一方で交通制限により、杭を施工現場まで搬送する際は数ｍの鋼管として運びこまれる。このため、施工現場において打設途中で接続して鋼管杭を構成する必要があり、この接続のためにねじ継手が用いられることがある。 Threaded joints of steel pipes are widely used for connecting a plurality of steel pipes, and are used for connecting steel pipes constituting steel pipe piles used for foundations of structures and prevention of landslides, for example. Such steel pipe piles have a required length of several tens of meters depending on the construction conditions, while due to traffic restrictions, they are carried as steel pipes of several meters when the piles are transported to the construction site. Therefore, it is necessary to connect the steel pipe piles in the middle of driving at the construction site, and a threaded joint may be used for this connection.
ねじ継手は、特許文献１に示すように、接続対象となる鋼管のそれぞれの端部に取り付けられ、施工現場でねじ継手を回転嵌合させることによって鋼管同士を接続する。
ねじ継手の嵌合に必要な回転数は、ねじの山数をねじの条数で除した数になるため、嵌合に必要な回転数を少なくするにはねじの条数を増やすことが有効である。
As shown in Patent Document 1, the threaded joint is attached to each end of the steel pipe to be connected, and the steel pipes are connected to each other by rotationally fitting the threaded joint at the construction site.
Since the number of rotations required for fitting a threaded joint is the number of threads divided by the number of threads of the screw, it is effective to increase the number of threads of the screw to reduce the number of rotations required for fitting. Is.
ねじ継手の回転嵌合は、雄ねじと雌ねじのねじ山始端部が、相手のねじ始端部におけるねじ底に入り込むことにより開始される。そして、回転嵌合が開始可能となるには、すべてのねじ山始端部が同時に互いのねじ始端部におけるねじ底部に入り込んで噛み合い始めなければならない。
回転嵌合開始時において、ねじが噛み合い始めるねじ山始端部およびねじ底の数はねじの条数に一致する。このため、ねじ継手の嵌合回転数を低減するためにねじの条数を増やせば増やすほど、ねじ山始端部とねじ底がすべて同時に噛み合うのが難しくなり、回転嵌合が開始されず施工性が低下してしまうという問題点があった。
Rotational fitting of a threaded joint is initiated by the thread starting ends of the male and female threads entering the thread bottom at the mating thread starting end. Then, in order for the rotary fitting to be able to start, all the thread start ends must simultaneously enter the thread bottoms at each other's thread start ends and begin to mesh with each other.
At the start of rotary fitting, the number of thread start ends and thread bottoms at which the screws begin to mesh matches the number of threads of the screw. Therefore, as the number of threads of the screw is increased in order to reduce the fitting rotation speed of the threaded joint, it becomes difficult for the thread start end and the screw bottom to mesh with each other at the same time, and the rotation fitting is not started and the workability is improved. There was a problem that it decreased.
本発明は、かかる課題を解決するためになされたものであり、条数が３条以上の多条ねじであっても、回転嵌合の開始が容易で嵌合施工性にすぐれた鋼管のねじ継手を提供することを目的としている。 The present invention has been made to solve such a problem, and even if the number of threads is a multi-threaded screw having 3 or more threads, the screw of a steel pipe which can easily start rotary fitting and has excellent fitting workability. It is intended to provide fittings.
（１）本発明に係る鋼管のねじ継手は、構造物の支持をする鋼管の端部に取り付けられて鋼管同士を接続する鋼管のねじ継手であって、
３条以上の雄ねじを有する雄継手部と、３条以上の雌ねじを有する雌継手部からなる多条ねじ継手であり、
前記雄継手部及び／又は前記雌継手部のねじ始端部におけるねじ底幅が先端ほど広がって、前記ねじ始端部以外のねじ底幅より広くなるようにねじ山始端部の先端形状が形成されていることを特徴とするものである。
(1) The threaded joint of a steel pipe according to the present invention is a threaded joint of a steel pipe attached to an end of a steel pipe that supports a structure and connects the steel pipes to each other.
It is a multi-threaded threaded joint consisting of a male joint part having 3 or more male threads and a female joint part having 3 or more female threads.
The tip shape of the thread start end is formed so that the screw bottom width at the screw start end of the male joint and / or the female joint widens toward the tip and becomes wider than the screw bottom width other than the screw start. It is characterized by being present.
（２）また、上記（１）に記載のものにおいて、前記ねじ山始端部の先端形状は、先端に向かって先細となる傾斜面部を有することを特徴とするものである。 (2) Further, in the one described in (1) above, the tip shape of the thread start end portion is characterized by having an inclined surface portion that tapers toward the tip.
（３）また、上記（２）に記載のものにおいて、前記ねじ山始端部の先端面の幅をδ、ねじ山幅をw、前記ねじ山始端部における前記傾斜面部を形成した部位の長さをL、リード角をα、先端形状を形成するための切削角度をβとして、下式を満たすことを特徴とするものである。
δ≧w/2
L≦2w
α+β≦45°
(3) Further, in the above-described item (2), the width of the tip surface of the thread starting end is δ, the thread width is w, and the length of the portion of the thread starting end where the inclined surface is formed. Is L, the lead angle is α, and the cutting angle for forming the tip shape is β, and the following equation is satisfied.
δ ≧ w / 2
L ≤ 2w
α + β ≤ 45 °
（４）また、上記（１）又は（２）に記載のものにおいて、前記ねじ山始端部の先端面に円弧状部を形成したことを特徴とするものである。 (4) Further, in the above-mentioned item (1) or (2), an arcuate portion is formed on the tip surface of the thread start end portion.
本発明に係る鋼管のねじ継手は、３条以上の雄ねじを有する雄継手部と、３条以上の雌ねじを有する雌継手部からなる多条ねじ継手であり、前記雄継手部及び／又は前記雌継手部のねじ始端部におけるねじ底幅が先端ほど広がって、前記ねじ始端部以外のねじ底幅より広くなるようにねじ山始端部の先端形状が形成されていることにより、回転嵌合の開始時に、雄ねじの先端面と雌ねじの先端面とが接触しにくくなり、それ故に、嵌合開始が容易にできる。特に、３条以上の多条ねじの場合には、ねじ山始端部およびねじ始端部におけるねじ底の数が条数と同じ数であるため、各ねじ山始端部とねじ始端部におけるねじ底での噛み合いが必要とされるが、本発明によれば各ねじ山始端部とねじ始端部におけるねじ底での噛み合いが容易になることで、ねじ継手全体としての嵌合開始が容易になる。 The threaded joint of a steel pipe according to the present invention is a multi-threaded threaded joint composed of a male joint portion having three or more male threads and a female joint portion having three or more female threads, and the male joint portion and / or the female. The tip shape of the thread start end is formed so that the screw bottom width at the screw start end of the joint portion widens toward the tip and becomes wider than the screw bottom width other than the screw start end, so that rotary fitting is started. Occasionally, the tip surface of the male thread and the tip surface of the female thread are less likely to come into contact with each other, and therefore the start of fitting can be facilitated. In particular, in the case of a multi-threaded screw with three or more threads, the number of thread bottoms at the thread start end and the thread start is the same as the number of threads, so that the thread bottoms at each thread start and thread start However, according to the present invention, the meshing at the screw bottom at each thread start end and the screw start ends becomes easy, so that the start of fitting of the entire threaded joint becomes easy.
本発明の一実施の形態に係る鋼管のねじ継手１（以下、単に「ねじ継手１」という）は、図１に示すように、構造物の支持をする鋼管３の端部に設けられて鋼管同士を接続するものであって、３条以上の雄ねじを有する雄継手部５ｍと、３条以上の雌ねじを有する雌継手部５ｆからなる多条ねじ継手であり、雄継手部５ｍ及び／又は雌継手部５ｆのねじ始端部７ｍ，７ｆにおけるねじ底幅Ｗｍ，Ｗｆが先端ほど広がって、ねじ始端部７ｍ，７ｆ以外のねじ底幅Ｗｍ，Ｗｆより広くなるようにねじ山始端部９ｍ，９ｆの先端形状が形成されているものである。
以下、各構成を詳細に説明する。
As shown in FIG. 1, the threaded joint 1 of the steel pipe according to the embodiment of the present invention (hereinafter, simply referred to as “threaded joint 1”) is provided at the end of the steel pipe 3 that supports the structure. It is a multi-threaded joint that connects each other and consists of a male joint portion 5 m having three or more male threads and a female joint portion 5f having three or more female threads, and is a male joint portion 5 m and / or a female. Thread bottom widths W m and W f at the screw start ends 7 m and 7 f of the joint portion 5 f widen toward the tip and become wider than the screw bottom widths W m and W f other than the screw start ends 7 m and 7 f. The tip shapes of 9m and 9f are formed.
Hereinafter, each configuration will be described in detail.
＜鋼管＞
鋼管３は、構造物を支持するものであり、例えば鋼管杭、鋼管矢板、鋼管柱等を構成する鋼管が例示できる。
<Steel pipe>
The steel pipe 3 supports a structure, and examples thereof include steel pipes constituting steel pipe piles, steel pipe sheet piles, steel pipe columns, and the like.
＜雄継手部、雌継手部＞
雄継手部５ｍは、雄ねじを有し、嵌合時に内側になるものである。雌継手部５ｆは、雌ねじを有し、嵌合時に外側となるものである。
雄ねじは、雄ねじ山１１ｍと雄ねじ底１３ｍからなり、３条以上の多条ねじである。同様に、雌ねじは、雌ねじ山１１ｆと雌ねじ底１３ｆからなり、３条以上の多条ねじである。
<Male joint, female joint>
The male joint portion 5 m has a male screw and is inside when fitted. The female joint portion 5f has a female screw and is on the outside when fitted.
The male thread is a multi-threaded screw having three or more threads, which consists of a male thread thread of 11 m and a male thread bottom of 13 m. Similarly, the female thread is composed of a female thread 11f and a female thread bottom 13f, and is a multi-threaded screw having three or more threads.
雄ねじ山１１ｍ及び雌ねじ山１１ｆは一般に、鍛造により作られた円筒体を切削加工することにより形成される。ねじ山の円筒体軸方向（図１の一点鎖線参照）の長さがねじ山幅ｗである（図１参照）。
雄ねじ底１３ｍ及び雌ねじ底１３ｆも、雄ねじ山１１ｍ及び雌ねじ山１１ｆと同様に、鍛造により作られた円筒体を切削加工することにより形成される。ねじ底の円筒体軸方向の長さがねじ底幅Ｗｍ及びＷｆである（図１参照）。
なお、ねじ底からねじ山の頂上までの円筒体軸直角方向の長さを、一般にねじ高さｈと呼ぶ（図１参照）。
The male thread 11m and the female thread 11f are generally formed by cutting a cylindrical body made by forging. The length of the thread in the cylindrical axial direction (see the alternate long and short dash line in FIG. 1) is the thread width w (see FIG. 1).
The male thread bottom 13m and the female thread bottom 13f are also formed by cutting a cylindrical body made by forging, similarly to the male thread 11m and the female thread 11f. The lengths of the screw bottom in the cylindrical body direction are the screw bottom widths W m and W f (see FIG. 1).
The length from the bottom of the screw to the top of the thread in the direction perpendicular to the cylindrical axis is generally called the screw height h (see FIG. 1).
雄継手部５ｍ及び雌継手部５ｆは、予め工場において鋼管３の端部に溶接によって接合され、施工現場で回転嵌合される。回転嵌合後の状態を図２に示す。本実施の形態では、下側の鋼管３の上端に雄継手部５ｍが、上側の鋼管３の下端部に雌継手部５ｆを取り付けた例を示しているが、これらは逆の配置であってもよい。 The male joint portion 5m and the female joint portion 5f are joined in advance to the end portion of the steel pipe 3 at the factory by welding, and are rotationally fitted at the construction site. The state after the rotary fitting is shown in FIG. In the present embodiment, an example is shown in which a male joint portion 5 m is attached to the upper end of the lower steel pipe 3 and a female joint portion 5f is attached to the lower end portion of the upper steel pipe 3, but these are arranged in reverse. May be good.
本実施の形態の特徴は、雄継手部５ｍ及び雌継手部５ｆのねじ山始端部９ｍ，９ｆの先端形状にあるので、この点を詳細に説明する。
図１に示すように、例えば雄継手部５ｍのねじ始端部７ｍにおいては、雄ねじ底幅Ｗｍが先端ほど広がって他の部分の雄ねじ底幅Ｗｍより広くなるようにねじ山始端部９ｍの先端形状が形成されている。具体的には、雄ねじ山１１ｍの先端が、先端に向かって図中上斜め方向に切削されて傾斜面部１５ｍが形成され、その結果、ねじ始端部７ｍの入り口が広がっている。同様に、雌継手部５ｆにおいては、雌ねじ山１１ｆの先端が先端に向かって図中下斜め方向に切削されて傾斜面部１５ｆが形成され、その結果、ねじ始端部７ｆの入り口が広がっている。
The feature of this embodiment is the shape of the tip of the thread start end portions 9m and 9f of the male joint portion 5m and the female joint portion 5f, and this point will be described in detail.
As shown in FIG. 1, for example, in a screw starting end portion 7 m of a male joint portion 5 m, a thread starting end portion 9 m has a male screw bottom width W m that widens toward the tip and becomes wider than a male screw bottom width W m of another portion. The tip shape is formed. Specifically, the tip of the male screw thread 11 m is cut diagonally upward in the drawing toward the tip to form an inclined surface portion 15 m, and as a result, the entrance of the screw start end portion 7 m is widened. Similarly, in the female joint portion 5f, the tip of the female screw thread 11f is cut diagonally downward in the drawing toward the tip to form an inclined surface portion 15f, and as a result, the entrance of the screw start end portion 7f is widened.
雄継手部５ｍ及び雌継手部５ｆのねじ山始端部９ｍ，９ｆの先端形状を上記のように形成することで、回転嵌合の開始時に、図３に示すように、雄ねじ山１１ｍの先端面１７ｍと雌ねじ山１１ｆの先端面１７ｆとが接触しにくくなり、それ故に、嵌合開始が容易にできる。多条ねじの場合には、前述したように、ねじ始端部７ｍ，７ｆの数が条数と同じ数であるため、各ねじ始端部７ｍ，７ｆでの嵌合が容易になることで、ねじ継手１全体としての嵌合開始が容易になる。
また、先端面１７ｍ，１７ｆに連続して傾斜面部１５ｍ，１５ｆが形成されているので、傾斜面部１５ｍ，１５ｆが嵌合方向へのガイドとして機能するので、この点でも、嵌合開始が容易になる。
By forming the tip shapes of the thread start ends 9m and 9f of the male joint portion 5m and the female joint portion 5f as described above, the tip surface of the male thread 11m is formed at the start of rotary fitting as shown in FIG. The 17m and the tip surface 17f of the female thread 11f are less likely to come into contact with each other, and therefore the fitting can be easily started. In the case of a multi-threaded screw, as described above, the number of screw start ends 7m and 7f is the same as the number of threads, so that the screws can be easily fitted at the screw start ends 7m and 7f. It becomes easy to start fitting the joint 1 as a whole.
Further, since the inclined surface portions 15m and 15f are formed continuously on the tip surfaces 17m and 17f, the inclined surface portions 15m and 15f function as guides in the fitting direction, so that the fitting start can be easily started at this point as well. Become.
ねじ継手の嵌合は、鋼管の管軸が地面に垂直になる方向で行う縦継ぎが一般的であるが、施工現場の条件によっては、鋼管の管軸が地面に水平になる方向で行う横継ぎの場合もあり、横継ぎで一体となった鋼管杭を立て起こして所定の場所へ打設することがある。
横継ぎでねじ継手を嵌合する場合、縦継ぎで嵌合する場合と比べると、嵌合したい鋼管同士の芯を合わせることが困難であるため、ねじ山始端部がねじ始端部におけるねじ底部に入り込みにくくなり、嵌合が開始されず施工性が低下してしまう。
この点、本発明では、ねじ山始端部に形成された傾斜面部が嵌合方向へのガイドとして機能するため、横継ぎの場合において鋼管同士の芯が多少一致していなくても、容易に嵌合することができ、施工性の低下を防止できる。
The threaded joint is generally fitted in a vertical joint in which the pipe axis of the steel pipe is perpendicular to the ground, but depending on the conditions at the construction site, the pipe axis of the steel pipe is horizontally connected to the ground. In some cases, it may be a joint, and a steel pipe pile that is integrated by a horizontal joint may be erected and placed in a predetermined place.
When fitting a threaded joint with a horizontal joint, it is more difficult to align the cores of the steel pipes to be fitted with each other than when fitting with a vertical joint, so the thread start end is at the thread bottom at the thread start. It becomes difficult to enter, fitting is not started, and workability is deteriorated.
In this respect, in the present invention, since the inclined surface portion formed at the thread start end function as a guide in the fitting direction, the steel pipes can be easily fitted even if the cores of the steel pipes do not coincide with each other in the case of horizontal joint. It can be combined and the deterioration of workability can be prevented.
なお、図１〜図３に示す例は、雄継手部５ｍ及び雌継手部５ｆの両方について、ねじ山始端部９ｍ，９ｆの先端形状を、傾斜面部１５ｍ、１５ｆを有する形状に加工したものであるが、本発明においては、雄継手部５ｍ及び雌継手部５ｆのいずれか一方のみのねじ山始端部９ｍ，９ｆの先端形状を上記のように加工する場合も含む。この場合であっても、加工を全くしない従来例に比較すると、嵌合開始が容易になるという効果が得られる。 In the example shown in FIGS. 1 to 3, the tip shapes of the thread starting ends 9m and 9f are processed into a shape having inclined surface portions 15m and 15f for both the male joint portion 5m and the female joint portion 5f. However, the present invention also includes a case where the tip shapes of the thread starting ends 9m and 9f of only one of the male joint portion 5m and the female joint portion 5f are processed as described above. Even in this case, the effect of facilitating the start of fitting can be obtained as compared with the conventional example in which no processing is performed.
次に、上記のようなねじ山始端部９ｍ，９ｆの先端形状の形成方法について説明する。
ねじ継手１の雄ねじ及び雌ねじは一般に、鍛造により作られた円筒体を旋盤加工し、ねじ底となる部分を切削してねじを形成する。旋盤加工の性質上、ねじの切りはじめには、図４（a）の斜線で示すように先端側が先細となった不完全ねじ部が形成される。不完全ねじ部はねじの嵌合時に潰れ、焼き付き等の不具合の原因になるため、一般的には、例えば特開2003-105755号公報に示されるように完全に除去され、図４（ｂ）の実線で示すように、ねじが噛み合い始めるねじ山始端部１９の先端面２１は、継手軸方向に平行な面を有していることが多い。
Next, a method of forming the tip shapes of the thread starting ends 9m and 9f as described above will be described.
The male and female threads of the screw joint 1 are generally formed by lathe a cylindrical body made by forging and cutting a portion to be a screw bottom to form a screw. Due to the nature of lathe processing, an incomplete threaded portion having a tapered tip side is formed at the beginning of thread cutting as shown by the diagonal line in FIG. 4 (a). Since the incompletely threaded portion causes problems such as crushing and seizure when the screw is fitted, it is generally completely removed as shown in, for example, Japanese Patent Application Laid-Open No. 2003-105755, and FIG. 4B is shown in FIG. As shown by the solid line, the tip surface 21 of the thread start end portion 19 at which the screws start to mesh often has a surface parallel to the joint axial direction.
上記のように、ねじ山始端部１９は従来においても、不完全ねじ部を除去するという加工工程を経て形成される。そこで、本発明のねじ山始端部９ｍ，９ｆの形成は、不完全ねじ部の除去工程において、不完全ねじ部の除去に代えて行うことで、通常の切削工程よりも切削工程を大幅に増やすことなく低コストで行うことができる。 As described above, the thread start end portion 19 is conventionally formed through a processing step of removing an incomplete thread portion. Therefore, the formation of the thread start ends 9m and 9f of the present invention is performed in the step of removing the incomplete thread portion instead of the removal of the incomplete thread portion, so that the cutting process is significantly increased as compared with the normal cutting process. It can be done at low cost without any need.
そして、ねじ山始端部９ｍ，９ｆの先端形状と不完全ねじ部との関係として、図５に示すように、本来は不完全ねじ部として削除される部分（斜線部分）に先端形状を形成してもよいし、あるいは、図６に示すように、先端側の一部が不完全ねじ部に相当する部位とし、その他の部位は本来のねじ部となる部位で形成してもよい。 Then, as a relationship between the tip shapes of the thread starting ends 9m and 9f and the incomplete threaded portion, as shown in FIG. 5, the tip shape is formed in the portion (hatched portion) that is originally deleted as the incomplete threaded portion. Alternatively, as shown in FIG. 6, a part on the tip end side may be a portion corresponding to an incomplete threaded portion, and the other portion may be formed as an original threaded portion.
次に、先端形状の好ましい形状について、雄ねじのねじ山始端部９ｍを示した図７に基づいて説明する。なお、本技術は雌ねじのねじ山始端部９ｆにも同様に適用できる。
先端形状において、先端面１７ｍの幅δが小さければ小さいほど、ねじ始端部７ｍのねじ底幅Ｗｍ（図１参照）を広く確保できるが、先端面１７ｍの幅δが小さいと、ねじ山始端部９ｍの強度が確保できない。そこで、ねじ底幅Ｗｍを広くすることとねじ山始端部９ｍの強度とのバランスの観点から、ねじ山幅w（ねじ山始端部９ｍ以外のねじ山の幅）に対してδ≧w/2となるように加工することが望ましい。
Next, a preferable shape of the tip shape will be described with reference to FIG. 7, which shows the thread start end portion 9 m of the male screw. The present technique can be similarly applied to the thread start end portion 9f of the female thread.
In the tip shape, the smaller the width δ of the tip surface 17 m, the wider the screw bottom width W m (see FIG. 1) of the screw start end 7 m can be secured, but if the width δ of the tip surface 17 m is small, the screw thread start end can be secured. The strength of the part 9m cannot be secured. Therefore, from the viewpoint of balancing the widening of the thread bottom width W m and the strength of the thread start end 9 m, δ ≧ w / with respect to the thread width w (the width of the thread other than the thread start end 9 m). It is desirable to process it so that it becomes 2.
また、先端形状における傾斜面部１５ｍを形成した部位の長さLが長くなりすぎると、所定のねじ山幅wを確保できない部分が多くなってしまい、ねじ山始端部９ｍの強度が確保できなくなるので、L≦2wとなるようにするのが望ましい。
さらに、先端形状の長さLが短い場合、相手のねじ山始端部９ｆとの接触角度γ（傾斜面部１５ｍが継手軸直交方向と成す角度）が大きくなりすぎるため、接触角度γを45°以下にするために、リード角αとねじ先端の切削角度βの和がα+β≦45°となるようにすることが望ましい。
Further, if the length L of the portion forming the inclined surface portion 15 m in the tip shape becomes too long, there are many portions where the predetermined screw thread width w cannot be secured, and the strength of the screw thread start end portion 9 m cannot be secured. , It is desirable that L ≤ 2w.
Further, when the length L of the tip shape is short, the contact angle γ (the angle formed by the inclined surface portion 15 m in the direction orthogonal to the joint axis) with the mating thread start end portion 9f becomes too large, so that the contact angle γ is 45 ° or less. Therefore, it is desirable that the sum of the lead angle α and the cutting angle β at the screw tip is α + β ≦ 45 °.
なお、上記の例では、ねじ山始端部９ｍ，９ｆの先端面１７ｍ，１７ｆが平坦面の場合を例示したが、本発明はこれに限られるものではなく、例えば図８に示すように、ねじ山始端部９ｍ，９ｆの先端面１７ｍ，１７ｆを円弧状にしてもよい。なお、図８において、斜線を付した部分は、本来、不完全ねじ部に相当する部分である。
このようにすることで、ねじ山始端部９ｍ，９ｆにおけるねじ底幅Ｗｍ，Ｗｆが広がると共に、円弧状の部分が当接したときに嵌合方向へのガイドとして機能する。
なお、傾斜面部１５ｍ，１５ｆを形成して、かつ先端面１７ｍ，１７ｆの全部または一部を円弧状にする態様でもよい。
In the above example, the case where the tip surfaces 17m and 17f of the thread start ends 9m and 9f are flat surfaces is illustrated, but the present invention is not limited to this, and for example, as shown in FIG. The tip surfaces 17m and 17f of the mountain starting ends 9m and 9f may be arcuate. In FIG. 8, the shaded portion is originally a portion corresponding to an incompletely threaded portion.
By doing so, the screw bottom widths W m and W f at the screw thread start ends 9 m and 9 f are widened, and when the arcuate portions come into contact with each other, they function as guides in the fitting direction.
In addition, the inclined surface portions 15m and 15f may be formed, and all or part of the tip surfaces 17m and 17f may be arcuate.
１ ねじ継手
３ 鋼管
５ｍ 雄継手部
５ｆ 雌継手部
７ｍ，７ｆ ねじ始端部
９ｍ，９ｆ ねじ山始端部
１１ｍ 雄ねじ山
１１ｆ 雌ねじ山
１３ｍ 雄ねじ底
１３ｆ 雌ねじ底
１５ｍ，１５ｆ 傾斜面部
１７ｍ，１７ｆ 先端面
１９ ねじ山始端部（通常加工）
２１ 先端面（通常加工）
Ｗｍ，Ｗｆ ねじ底幅
ｗ ねじ山幅
ｈ ねじ山高さ
1 Thread joint 3 Steel pipe 5m Male joint 5f Female joint 7m, 7f Thread start end 9m, 9f Thread start end 11m Male thread 11f Female thread 13m Male thread bottom 13f Female thread bottom 15m, 15f Inclined surface 17m, 17f Tip surface 19m, 17f Mountain start (normal processing)
21 Tip surface (normal processing)
W m , W f Thread bottom width w Thread width h Thread height
Claims (1)
３条以上の雄ねじを有する雄継手部と、３条以上の雌ねじを有する雌継手部からなる多条ねじ継手であり、
前記雄継手部及び／又は前記雌継手部のねじ始端部におけるねじ底幅が先端ほど広がって、前記ねじ始端部以外のねじ底幅より広くなるようにねじ山始端部の先端形状が形成されており、
前記ねじ山始端部の先端形状は、先端に向かって先細となる傾斜面部を有し、
前記ねじ山始端部の先端面の幅をδ、ねじ山幅をw、前記ねじ山始端部における前記傾斜面部を形成した部位の長さをL、リード角をα、先端形状を形成するための切削角度をβとして、下式を満たすことを特徴とする鋼管のねじ継手。
δ≧w/2
L≦2w
α+β≦45° A threaded joint of a steel pipe that is attached to the end of a steel pipe that supports a structure and connects the steel pipes to each other.
It is a multi-threaded threaded joint consisting of a male joint part having 3 or more male threads and a female joint part having 3 or more female threads.
The tip shape of the thread start end is formed so that the screw bottom width at the screw start end of the male joint and / or the female joint widens toward the tip and becomes wider than the screw bottom width other than the screw start. Ori,
The tip shape of the thread starting end has an inclined surface portion that tapers toward the tip.
The width of the tip surface of the thread starting end is δ, the thread width is w, the length of the portion of the thread starting end where the inclined surface is formed is L, the lead angle is α, and the tip shape is formed. A threaded joint of a steel pipe characterized by satisfying the following formula with a cutting angle of β .
δ ≧ w / 2
L ≤ 2w
α + β ≤ 45 °
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| US5320467A (en) * | 1993-05-20 | 1994-06-14 | General Electric Company | Positive thread start fastener |
| JP3747594B2 (en) * | 1996-10-22 | 2006-02-22 | Ｊｆｅスチール株式会社 | Steel pipe pile joints |
| JP2002213425A (en) * | 2000-11-14 | 2002-07-31 | Meidoo:Kk | Bolt |
| JP3797316B2 (en) * | 2002-09-27 | 2006-07-19 | 株式会社メイドー | Bolts and manufacturing dies |
| US9810029B2 (en) * | 2011-01-26 | 2017-11-07 | Bly Ip Inc. | Drill string components resistant to jamming |
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