JP6575553B2 - Parallel threaded joint for structural steel pipes - Google Patents
Parallel threaded joint for structural steel pipes Download PDFInfo
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- JP6575553B2 JP6575553B2 JP2017069609A JP2017069609A JP6575553B2 JP 6575553 B2 JP6575553 B2 JP 6575553B2 JP 2017069609 A JP2017069609 A JP 2017069609A JP 2017069609 A JP2017069609 A JP 2017069609A JP 6575553 B2 JP6575553 B2 JP 6575553B2
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- 229910000746 Structural steel Inorganic materials 0.000 title claims description 39
- 229910000831 Steel Inorganic materials 0.000 claims description 37
- 239000010959 steel Substances 0.000 claims description 37
- 239000002184 metal Substances 0.000 claims description 8
- 238000009434 installation Methods 0.000 claims description 5
- 238000005304 joining Methods 0.000 claims description 5
- 239000000463 material Substances 0.000 description 10
- 238000005452 bending Methods 0.000 description 6
- 230000007423 decrease Effects 0.000 description 5
- 230000000694 effects Effects 0.000 description 5
- 238000010276 construction Methods 0.000 description 3
- 238000003466 welding Methods 0.000 description 3
- 230000005540 biological transmission Effects 0.000 description 2
- 238000005520 cutting process Methods 0.000 description 2
- 238000003780 insertion Methods 0.000 description 2
- 230000037431 insertion Effects 0.000 description 2
- 230000006835 compression Effects 0.000 description 1
- 238000007906 compression Methods 0.000 description 1
- 238000010586 diagram Methods 0.000 description 1
- 238000002474 experimental method Methods 0.000 description 1
- 239000000314 lubricant Substances 0.000 description 1
- 238000003754 machining Methods 0.000 description 1
- 238000004519 manufacturing process Methods 0.000 description 1
- 230000009347 mechanical transmission Effects 0.000 description 1
- 238000000034 method Methods 0.000 description 1
- 230000002265 prevention Effects 0.000 description 1
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Description
本発明は、土木、建築分野における鋼管杭、鋼管矢板、柱材などの構造体を構成する鋼管の接合に用いられる構造体鋼管用平行ねじ継手に関する。 TECHNICAL FIELD The present invention relates to a parallel threaded joint for structural steel pipes used for joining steel pipes constituting structural bodies such as steel pipe piles, steel pipe sheet piles, and column materials in the civil engineering and construction fields.
鋼管杭や鋼管矢板、柱材などの構造体を構成する鋼管（以下、「構造体鋼管」という）の接合は溶接接合によることが一般的であるが、火気が使えない場合や接合時間を短縮する必要がある場合などには、例えば特許文献１、２に開示されているような機械式継手が用いられるケースが増えている。 Steel pipes (hereinafter referred to as “structural steel pipes”) that make up structures such as steel pipe piles, steel pipe sheet piles, and column materials are generally welded joints, but when fire cannot be used or the joint time is shortened In cases where it is necessary to do so, for example, cases where mechanical joints such as those disclosed in Patent Documents 1 and 2 are used are increasing.
従来の構造体鋼管用平行ねじ継手は、一般に構造体を構成する部材として圧縮力、曲げ、引張力に対して接続される鋼管と同等以上の耐力が要求されるとともに、通常１回転以上回転させて締結がなされるようねじ山数、ねじピッチ、条数などのねじ仕様の設定がなされている。 Conventional parallel threaded joints for structural steel pipes are generally required to have a strength equal to or greater than that of steel pipes connected to compressive force, bending, and tensile force as members constituting the structural body, and are usually rotated one or more times. Screw specifications such as the number of threads, screw pitch, and number of threads are set so that they can be fastened.
しかしながら、近年、構造体鋼管のサイズがφ700mm以上となるような大径化が進んでおり、このような大径の構造体鋼管を平行ねじ継手で接合した場合、従来のように締結に際して１回転以上回転させることの作業負荷の増大あるいは、回転させることそのものが困難なケースがみられるようになってきた。以下、この点を具体的に説明する。 However, in recent years, the diameter of the structural steel pipe has been increased so that the diameter of the structural steel pipe becomes 700 mm or more. When such a large-diameter structural steel pipe is joined with a parallel threaded joint, one rotation is required for fastening as in the past. As described above, there have been cases where the work load is increased or the rotation itself is difficult. This point will be specifically described below.
図９は、杭打機２１で鋼管杭を施工する際の作業の様子を示している。ねじ継手２３を取り付けた鋼管（以下、「ねじ継手付鋼管２５」という）を回転接合する際、通常、ねじ継手付鋼管２５に回転トルクを与えるための回転バンド２７と回転棒２９を取り付けるが、鋼管が大径になるにしたがって、回転させるために大きなトルクが必要となり、所定のトルクを与えるために回転棒２９を長くする必要が生じる。しかし、回転棒２９を長くした場合、回転作業の際に回転棒２９が杭打機２１に接触してしまうため、回転棒２９のセット位置を付け替え直すかもしくは杭打機２１を回転棒２９に接触しない位置まで退避しなくてはならず、作業性の低下につながるという問題がある。 FIG. 9 shows a state of work when constructing a steel pipe pile with the pile driving machine 21. When a steel pipe to which a threaded joint 23 is attached (hereinafter referred to as “steel pipe 25 with a threaded joint”) is rotationally joined, a rotating band 27 and a rotating rod 29 for applying rotational torque to the threaded jointed steel pipe 25 are usually attached. As the steel pipe becomes larger in diameter, a large torque is required to rotate it, and the rotating rod 29 needs to be lengthened to give a predetermined torque. However, when the rotating rod 29 is lengthened, the rotating rod 29 comes into contact with the pile driving machine 21 during the rotating operation, so that the setting position of the rotating rod 29 is changed or the pile driving machine 21 is changed to the rotating rod 29. There is a problem that it is necessary to retract to a position where it does not contact, which leads to a decrease in workability.
上記の課題に対する解決策としては、ねじ継手２３の締結に至る回転量を半回転以下にすることで回転棒２９のセット位置の付け替えをなくして作業性を向上することが可能である。
条数がＮで嵌合するねじ山数がＭの場合、嵌合完了までの回転数はＭ／Ｎで規定されるので、ねじの回転数を減らすには条数を増やすか、ねじ山数を減らす必要があり、回転量を半回転以下にするにはＭ／Ｎ≦０．５にすることが必要である。
なお、Ｍ、Ｎは自然数であるため、ここでは条数Ｎは２以上、ねじ山数Ｍは１以上となる。
As a solution to the above-mentioned problem, it is possible to improve the workability by changing the set position of the rotating rod 29 by setting the amount of rotation leading to the fastening of the screw joint 23 to half or less.
When the number of threads is N and the number of threads to be fitted is M, the number of rotations until the completion of fitting is defined by M / N. Therefore, to reduce the number of rotations of the screw, increase the number of threads or the number of threads In order to reduce the rotation amount to half or less, it is necessary to satisfy M / N ≦ 0.5.
Since M and N are natural numbers, the number N of threads is 2 or more and the number of threads M is 1 or more.
条数が多いほど嵌合のための回転量を減らすことが出来るが、一方で条数を多くすると加工が難しくなるため、例えばφ700mmの継手の場合、通常は８条程度以下が望ましい。８条ねじで回転数を０．５とすれば、Ｍ／８＝０．５からＭ＝４となり、嵌合する山数の最大が４山となる。なお、４条ねじの場合には、Ｍ／４＝０．５からＭ＝２となり、嵌合する山数は２山となる。
このように嵌合する山数が少なくなると、鋼管杭のような構造体鋼管の接合に用いるねじ継手のように軸直交方向でかつ周方向の多方向から応力が作用する場合には、以下のような問題がある。
As the number of strips increases, the amount of rotation for fitting can be reduced. On the other hand, if the number of strips is increased, processing becomes difficult. If the number of rotations is 0.5 with an 8-thread screw, M / 8 = 0.5 to M = 4, and the maximum number of threads to be fitted is 4 threads. In the case of a 4-thread screw, M / 4 = 0.5 to M = 2, and the number of threads to be fitted is two.
When the number of ridges to be fitted in this way is reduced, when stress acts from multiple directions in the direction perpendicular to the axis and in the circumferential direction as in the threaded joint used for joining structural steel pipes such as steel pipe piles, There is a problem like this.
図１０はねじ継手３１（ここでは、図を見やすくするため、１条ねじで、ねじ山数が６山存在するものを図示している。）を模式的に示したもので、図１０（ａ）が雄継手３３、図１０（ｂ）が雌継手３５（全体は図示せず）のねじ部を示している。なお、図１０において、雄継手３３のねじ山（雄ねじ山３７）を白抜きの平行四辺形で示し、雌継手３５のねじ山（雌ねじ山３９）を黒塗りの平行四辺形で示している。このねじ山の図示方法は、他の図においても同様である。
このねじ継手３１の嵌合完了状態を図１１に示している。周方向に見た場合、嵌合する山数はほとんどのところで５山となっているが、図１１（ａ）は嵌合する山数が少ないところがある場合（４山のところが存在する）を示し、図１１（ｂ）は嵌合する山数が多いところがある場合（６山のところが存在する）を示している。これらの状態は、ねじの切削長さやねじ切りの開始位置などの影響を受け、構造体鋼管の継手では一般的にはそれほど厳密には管理されておらず、嵌合する山数が５山として扱われている。
FIG. 10 schematically shows a threaded joint 31 (here, in order to make the drawing easier to see, a single thread and six threads are shown). ) Shows the male joint 33, and FIG. 10B shows the threaded portion of the female joint 35 (the whole is not shown). In FIG. 10, the thread of the male joint 33 (male thread 37) is shown by a white parallelogram, and the thread of the female joint 35 (female thread 39) is shown by a black parallelogram. The method of showing the thread is the same in other drawings.
The fitting completion state of the threaded joint 31 is shown in FIG. When viewed in the circumferential direction, the number of ridges to be fitted is almost 5 ridges, but FIG. 11 (a) shows a case where there are few places to be fitted (4 ridges exist). FIG. 11 (b) shows a case where there are a lot of mountains to be fitted (there are 6 mountains). These conditions are affected by the cutting length of the screw and the starting position of the threading, and are not generally managed strictly in the joints of structural steel pipes. It has been broken.
ねじ継手３１では嵌合完了状態において嵌合する山数が周方向で異なることになるが、図１１に示すように山数が多い場合には周方向における嵌合数の違いは鋼管杭の性能にさほど影響を与えることはない。つまり、嵌合する山数が少ない場合でも多い場合の（４/５）×100％＝80％であり、嵌合する山数の全体に対する割合の差異が少ない。 In the threaded joint 31, the number of ridges to be fitted differs in the circumferential direction in the fitting completion state, but when the number of ridges is large as shown in FIG. 11, the difference in the number of fittings in the circumferential direction is the performance of the steel pipe pile. It will not affect so much. That is, even when the number of ridges to be fitted is small, it is (4/5) × 100% = 80% when there are many ridges.
しかしながら、図１２に示すように、嵌合する山数が２山のねじ継手４１の場合には２山嵌合の部分と１山嵌合の部分が生じ、嵌合する山数が多いところと少ないところでの差異が極端（少ないところは多いところの50％）になってしまい、その影響が無視できなくなり、ねじ継手４１の強度や剛性に方向性が生じて構造体鋼管の継手として望ましくない。 However, as shown in FIG. 12, in the case of a threaded joint 41 having two threads to be fitted, a two-fitting part and a one-fitting part are produced, and the number of fittings is large. The difference in the small number becomes extreme (the small number is 50% of the large number), and the influence cannot be ignored, and the strength and rigidity of the threaded joint 41 are generated, which is not desirable as a joint of the structural steel pipe.
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、回転角度を少なくして作業効率を向上すると共に強度や剛性に方向性の少ない構造体鋼管用平行ねじ継手を得ることを目的としている。 The present invention has been made to solve such a problem, and has an object to obtain a parallel threaded joint for a structural steel pipe having a reduced rotational angle to improve work efficiency and less direction in strength and rigidity. .
（１）本発明に係る構造体鋼管用平行ねじ継手は、構造体を構成する鋼管の接合に用いられるものであって、嵌合するねじ山数Ｍとねじ条数Ｎとの関係がＭ／Ｎ≦0.5に設定されると共に、Ｍ≦４であり、嵌合するねじ山数がＭと異なる範囲が、継手周方向長さに対して所定割合以下に設定されていることを特徴とするものである。 (1) The parallel threaded joint for structural steel pipes according to the present invention is used for joining steel pipes constituting a structural body, and the relationship between the number M of thread threads to be fitted and the number N of thread strips is M /. N ≦ 0.5 and M ≦ 4, and the range in which the number of threads to be fitted is different from M is set to a predetermined ratio or less with respect to the joint circumferential length. It is.
（２）また、上記（１）に記載のものにおいて、嵌合開始部にある雄ねじ山及び雌ねじ山の不完全ねじ部が除去されていることを特徴とするものである。 (2) Further, in the above (1), the male screw thread and the incomplete screw part of the female screw thread at the fitting start part are removed.
（３）また、上記（２）に記載のものにおいて、前記不完全ねじ部を除去した部位に逆回転防止金具の設置位置が設定されていることを特徴とするものである。 (3) Further, in the above-mentioned (2), the installation position of the reverse rotation preventing metal fitting is set at a portion where the incomplete thread portion is removed.
（４）また、上記（１）乃至（３）のいずれかに記載のものにおいて、ねじ山の嵌合効率が0.6以上を満たすようにねじ山高さ及びねじ山のクリアランスが設定されていることを特徴とするものである。 (4) Further, in any of the above (1) to (3), the thread height and the thread clearance are set so that the thread fitting efficiency satisfies 0.6 or more. It is a feature.
（５）また、上記（１）乃至（４）のいずれかに記載のものにおいて、ねじリード角θが、θ≦5.7°を満足するよう設定されていることを特徴とするものである。 (5) Further, in any of the above (1) to (4), the screw lead angle θ is set so as to satisfy θ ≦ 5.7 °.
本発明においては、構造体に用いられる構造体鋼管用平行ねじ継手であって、嵌合するねじ山数Ｍとねじ条数Ｎとの関係がＭ／Ｎ≦0.5に設定されると共に、嵌合するねじ山数が４以下であり、嵌合山数がＭと異なる範囲が、継手周方向長さに対して所定割合以下に設定されていることにより、構造体鋼管の接合に際して回転量を少なくして作業効率を向上できると共に強度や剛性に方向性の少ない構造体鋼管用平行ねじ継手が得られる。 In this invention, it is a parallel threaded joint for structural steel pipes used for a structure, and the relationship between the number M of threads to be fitted and the number N of threads is set to M / N ≦ 0.5, and fitting The number of screw threads to be used is 4 or less, and the range in which the number of fitting threads is different from M is set to a predetermined ratio or less with respect to the joint circumferential length, thereby reducing the amount of rotation when joining the structural steel pipes Thus, it is possible to improve the working efficiency and obtain a parallel threaded joint for a structural steel pipe with less direction in strength and rigidity.
本発明の一実施の形態に係る構造体鋼管用平行ねじ継手１は、土木、建築分野における鋼管杭、鋼管矢板、柱材などの構造体に用いられるものであって、図１に示すように、雄継手３と雌継手５の嵌合するねじ山数Ｍとねじ条数Ｎとの関係がＭ／Ｎ≦0.5に設定されると共に、嵌合山数が４山以下であり、嵌合山数がＭと異なる範囲が、継手周方向長さに対して所定割合（本例では、１０％）以下に設定されていることを特徴とするものである。なお、図１の例は、雄継手３における雄ねじ山７と雌継手５における雌ねじ山９がそれぞれ２山の４条ねじの例である。
以下、構造体鋼管用平行ねじ継手１の各構成要件について詳細に説明する。
A parallel threaded joint 1 for a structural steel pipe according to an embodiment of the present invention is used for a structural body such as civil engineering, a steel pipe pile, a steel pipe sheet pile, a pillar material in the construction field, and as shown in FIG. The relationship between the number of threads M and the number of threads N that the male joint 3 and female joint 5 are fitted to is set to M / N ≦ 0.5, and the number of threads is 4 or less. The range in which the number is different from M is set to a predetermined ratio (10% in this example) or less with respect to the joint circumferential length. The example of FIG. 1 is an example of a four-thread screw in which the male thread 7 in the male joint 3 and the female thread 9 in the female joint 5 are two threads.
Hereinafter, each component of the parallel threaded joint 1 for a structural steel pipe will be described in detail.
＜ねじ山数Ｍとねじ条数Ｎとの関係＞
嵌合するねじ山数Ｍとねじ条数Ｎとの関係は、Ｍ／Ｎ≦0.5に設定されており、Ｍは２で４以下となっている。このように設定することで、回転量（回転角度）を半回転（180度）以内にしてねじを締め込むことができる。これによって、前述したような大径の杭に適用した場合において、回転棒のセット位置の付け替えや杭打機の退避が不要となり、作業性を向上することができる。
<Relationship between the number of threads M and the number N of threads>
The relationship between the number M of threads to be fitted and the number N of threads is set to M / N ≦ 0.5, and M is 2 and 4 or less. By setting in this way, the screw can be tightened with the rotation amount (rotation angle) within a half rotation (180 degrees). Accordingly, when applied to a large-diameter pile as described above, it is not necessary to change the setting position of the rotating rod and to evacuate the pile driving machine, thereby improving workability.
ねじの嵌合開始点は、不完全ねじ部がある場合、嵌合の起点が不完全ねじ部の開始位置からになってしまうため、ねじの回転量を少なくする観点からは、不完全ねじ部は除去することが好ましい。なお、継手の力学性能面では、不完全ねじ部はねじ山形状が不完全である分、力学伝達性能が劣ることから、除去したとしても力学性能への影響は小さい。 If there is an incomplete thread, the starting point of the screw fitting will be from the start position of the incomplete thread, so from the viewpoint of reducing the amount of screw rotation, the incomplete thread Is preferably removed. In terms of the mechanical performance of the joint, the incomplete thread portion is inferior in the mechanical transmission performance due to the incomplete thread shape, so even if it is removed, the influence on the mechanical performance is small.
図２に示す破線の丸で囲んだ部分が嵌合開始位置にある雄ねじ山７及び雌ねじ山９の不完全ねじ部であるが、これがある場合に、ねじの回転量が多くなることを図３、図４に基づいて説明する。図３、図４はねじを展開して模式的に示す図であり、図３が不完全ねじ部が有る場合、図４が不完全ねじ部を除去した場合の嵌合完了状態を示している。図３と図４は共に完全ねじ部の嵌合長さは同じであるが、図３の場合の回転長はａであり、図４の場合の回転長はａよりも短いｂとなる。 2 are the incomplete thread portions of the male screw thread 7 and the female screw thread 9 at the fitting start position. When this portion is present, the amount of rotation of the screw increases. This will be described with reference to FIG. FIG. 3 and FIG. 4 are diagrams schematically showing the unfolded screw. FIG. 3 shows a completed state when FIG. 3 has an incomplete screw portion and FIG. 4 shows that the incomplete screw portion is removed. . 3 and 4 have the same fitting length of the complete thread portion, the rotation length in the case of FIG. 3 is a, and the rotation length in the case of FIG. 4 is b shorter than a.
不完全ねじ部を除去した部位に逆回転防止金具の設置位置が設定されていることがさらに好ましい。
図５（ａ）は、雄継手３において不完全ねじ部を除去した部位に逆転防止金具としてピンが挿入されるピン挿入孔１１を設けたものである。
逆回転防止金具の設置位置に関し、従来は図５（ｂ）に示すように、雄ねじ山７が形成された部位のさらに先端側に設けられていたために、継手長が長くなり、その分だけ継手製造に使用する鋼材量が増加するとともに、ねじ加工における切削加工長も長くなってしまい、コストアップにつながっていた。
これに対して、図５（ａ）に示したように、不完全ねじ部を除去した部位に逆回転防止金具の設置位置を設けることで、継手長さを長くする必要がなくなり経済的な構造にすることが出来る。
More preferably, the installation position of the reverse rotation preventing metal fitting is set at the site where the incomplete screw portion is removed.
FIG. 5A shows a pin insertion hole 11 into which a pin is inserted as an anti-reverse fitting at a portion where the incomplete thread portion is removed from the male joint 3.
With respect to the installation position of the reverse rotation preventing metal fitting, conventionally, as shown in FIG. 5 (b), since the male screw thread 7 is provided further on the tip side, the joint length becomes longer, and the joint length is increased accordingly. As the amount of steel used for manufacturing increased, the cutting length in threading also increased, leading to increased costs.
On the other hand, as shown in FIG. 5 (a), by providing an installation position of the reverse rotation preventing metal fitting at the site where the incomplete thread portion is removed, there is no need to lengthen the joint length and an economical structure. Can be made.
＜嵌合山数がＭと異なる範囲＞
本実施の形態の構造体鋼管用平行ねじ継手１は、嵌合山数がＭと異なる範囲が継手周方向長さの１０％以下に設定されている。
嵌合山数がＭと異なる範囲について、図１に示す４条ねじ（山数Ｍ＝２）について説明する。
この例では嵌合山数は、１山の部分と２山の部分があるので、図１において、嵌合山数がＭと異なる範囲は、１山嵌合区間として示す範囲であり、この範囲が全周長の１０％以下に設定されている。
<Range where the number of fitting ridges is different from M>
In the parallel threaded joint 1 for structural steel pipes of the present embodiment, the range in which the number of fitting ridges is different from M is set to 10% or less of the joint circumferential length.
The four-thread screw (number of threads M = 2) shown in FIG.
In this example, the number of fitting ridges includes a single mountain portion and two mountain portions. In FIG. 1, the range where the number of fitting ridges is different from M is a range indicated as a single mountain fitting section. Is set to 10% or less of the entire circumference.
嵌合山数がＭと異なる範囲を全周長の１０％以下にすることで、強度や剛性に方向性が緩和され、継手としての性能を十分に発揮できる。
この理由について、分かりやすい例として、図６に示すように、構造体鋼管用平行ねじ継手１で接合された鋼管が曲げを受ける場合を例に挙げて説明する。図６（ｂ）は鋼管に曲げが作用した状態を示し、図６（ａ）は図６（ｂ）の矢視Ａ−Ａ部（構造体鋼管用平行ねじ継手１の断面）の応力状態を示している。
By setting the range where the number of fitting ridges is different from M to 10% or less of the total circumference, the directionality is relaxed in strength and rigidity, and the performance as a joint can be sufficiently exhibited.
As an easy-to-understand example, this reason will be described with reference to an example in which the steel pipe joined by the parallel threaded joint 1 for a structural steel pipe is subjected to bending as shown in FIG. FIG. 6 (b) shows a state in which bending is applied to the steel pipe, and FIG. 6 (a) shows the stress state of the AA portion (cross section of the parallel threaded joint 1 for a structural steel pipe) in FIG. 6 (b). Show.
構造体鋼管用平行ねじ継手１が曲げを受けた場合、引張縁や圧縮縁の部位が最も厳しい状態になるので、図６に示すように、引張縁や圧縮縁に嵌合山数がＭと異なるところが位置すると、強度や剛性への影響が大きい。もっとも、ねじ山は周方向に連続しているため、Ｍと異なる範囲が狭ければ、実際には周囲（嵌合山数が所定数Ｍのところ）の影響を受け、大きな違いが生じない。そして、このような大きな違いが生じないためには、嵌合山数がＭと異なる範囲の全周長に対する割合が１０％以下であればよい。もっとも、この割合は、接合される鋼管の用途や、使用態様等によって変わることがあり、予め定めた所定割合以下に設定すればよい。 When the parallel threaded joint 1 for a structural steel pipe is bent, the tensile edge and the compression edge are in the most severe state. Therefore, as shown in FIG. If different places are located, the effect on strength and rigidity is large. However, since the screw threads are continuous in the circumferential direction, if the range different from M is narrow, it is actually influenced by the surroundings (where the number of fitting threads is a predetermined number M), and no significant difference occurs. And in order not to produce such a big difference, the ratio with respect to the perimeter of the range where the number of fitting ridges differs from M should just be 10% or less. However, this ratio may vary depending on the use of the steel pipe to be joined, the usage mode, and the like, and may be set to a predetermined ratio or less.
なお、上記の割合が例えば全周長の１０％以下ということはＮ条のねじの場合は、１条当たり10/N%以下ということであり、条数が多いほど１条当たりの範囲は狭くなり、より違いが生じにくくなる。
例えばΦ1000mmの８条ねじで、１条当たりの範囲長さを鋼管外周長で考えると、1000π×10/8/100≒39mmである。
実際のねじの加工公差を考えると、嵌合時の回転量がこの程度ばらつくことは容易に発生するため、10%以下にコントロールするためには、ねじ加工後に一度嵌め合わせた上で、ねじの嵌合長さを調整することが望ましい。
For example, if the above ratio is 10% or less of the entire circumference, it means 10 / N% or less per 1 thread in the case of N threads, and the larger the number of threads, the narrower the range per 1 thread. The difference is less likely to occur.
For example, assuming that the range length per one piece is 8 mm screw with Φ1000mm in terms of the outer circumference of the steel pipe, it is 1000π × 10/8/100 ≒ 39mm
Considering the actual thread machining tolerance, it is easy for the amount of rotation at the time of fitting to vary to this extent, so in order to control it to 10% or less, after fitting, It is desirable to adjust the fitting length.
ねじ部に作用する曲げ、引張外力に対しては、ねじ山数が少なくなるにつれてねじ山を介して伝わる応力の分散効果は小さくなり、ねじ山が多い場合に比べて小さな作用荷重でねじ山部又はねじ底部が局所的に降伏あるいは塑性化してしまう傾向がみられる。ねじ山部あるいはねじ山底部に降伏あるいは塑性化が生じてしまうとねじ部径が広がろうとする変形が生じ、ねじ山の噛み合わせ量が急激に低下し、それに伴いねじ耐力も一気に低下し、ねじ外れに至る。
このような観点から、山数が４山以下の場合には、ねじ山のクリアランスは小さい方が好ましい。
For bending and tensile external forces acting on the threaded portion, the effect of dispersing the stress transmitted through the thread becomes smaller as the number of threads decreases, and the threaded portion with a smaller working load than when there are many threads. Or the tendency for the screw bottom part to yield or plasticize locally is seen. If yielding or plasticization occurs at the thread or thread bottom, deformation that causes the thread diameter to expand occurs, the amount of thread meshing suddenly decreases, and the screw strength also decreases at a stretch. Leads to unscrewing.
From such a viewpoint, when the number of ridges is four or less, it is preferable that the clearance of the thread is small.
一方、鋼管杭用に用いるような構造体鋼管用平行ねじ継手では、継手部の材質に高強度材を使用することや、ねじ加工後の必要板厚確保の観点から、鋼管に直接ねじ切り加工することはなく、ねじ継手を別途製作して、鋼管管端とねじ継手の片側を工場溶接して用いられることが一般的である。
この時、鋼管とねじ継手の溶接熱影響によりねじ継手に微小変形が生じる。このため、ねじ寸法は、鋼管との溶接取付後もねじの嵌合性を確保するために、雄ねじ山と雌ねじ山間に予めクリアランスを設定しておく必要がある。ただし、クリアランスを大きくするにつれて、上述のように、ねじの嵌合効率（噛み合わせ量）が減少してしまい、曲げや引張外力に対して外れやすい継手になってしまう。
従来、嵌合するねじ山数が５以上のねじ継手において、ねじの嵌合効率を0.5程度以上になるよう、ねじ山高さやねじ山間のクリアランスを設定がなされていたが、本発明では、Ｍ／Ｎ≦0.5かつＭ≦４を満足することを前提とするため、条件が異なる。該当する構造体鋼管用平行ねじ継手について実験を重ねた結果、ねじの嵌合効率0.6以上、より望ましくは0.7以上になるよう断面設定する必要があることを見出した。
On the other hand, in parallel threaded joints for structural steel pipes, such as those used for steel pipe piles, high-strength materials are used as the material for joints, and threading is directly performed on steel pipes from the viewpoint of securing the necessary plate thickness after threading. In general, a threaded joint is manufactured separately, and a steel pipe end and one side of the threaded joint are generally factory welded.
At this time, micro deformation occurs in the threaded joint due to the effect of welding heat between the steel pipe and the threaded joint. For this reason, it is necessary to set a clearance in advance between the male screw thread and the female screw thread in order to ensure the screw fitting property even after the welding attachment with the steel pipe. However, as the clearance is increased, the screw fitting efficiency (meshing amount) decreases as described above, and the joint is easily detached from bending and tensile external force.
Conventionally, in threaded joints with 5 or more thread threads to be fitted, the thread height and clearance between threads have been set so that the thread fitting efficiency is about 0.5 or more. Since it is assumed that N ≦ 0.5 and M ≦ 4 are satisfied, the conditions are different. As a result of repeated experiments on the corresponding parallel threaded joint for structural steel pipes, it was found that the cross-section must be set so that the screw fitting efficiency is 0.6 or more, more preferably 0.7 or more.
図７はこの嵌合効率を説明する説明図であり、図７（ａ）は雄継手３の雄ねじ山７と雌継手５の雌ねじ山９とがねじ中央で嵌合している状態を示し、図７（ｂ）は雄ねじ山７が図中上方に最もずれた状態を示している。
嵌合率は、図７（ｂ）において、ねじ山高さをｈ、噛み合わせ量をｆとしたとき、ｆ/ｈであり、この値が0.6以上が好ましく、より好ましくは0.7以上である。
FIG. 7 is an explanatory view for explaining this fitting efficiency. FIG. 7A shows a state in which the male thread 7 of the male joint 3 and the female thread 9 of the female joint 5 are fitted at the center of the screw. FIG. 7B shows a state where the male screw thread 7 is most shifted upward in the drawing.
In FIG. 7B, the fitting rate is f / h, where h is the thread height and f is the meshing amount, and this value is preferably 0.6 or more, and more preferably 0.7 or more.
なお、クリアランスの大きさは、一般的に継手部の径が大きいほど大きくする必要があるが、継手によって連結される鋼管の径をＤ、雌継手５のねじ山底内径Ｄbi、雄継手３のねじ山での外径Ｄpoとしたときに、クリアランスはＤbi−Ｄpoとなり、この値がＤの0.10〜0.30%に設定するのが好ましい。 In general, the clearance needs to be increased as the diameter of the joint portion increases, but the diameter of the steel pipe connected by the joint is D, the thread bottom inner diameter Dbi of the female joint 5, and the male joint 3. The clearance is Dbi-Dpo when the outer diameter Dpo at the thread is set, and this value is preferably set to 0.10 to 0.30% of D.
＜ねじリード角θ＞
また、ねじリード角θが、θ≦5.7°を満足するよう設定されていることが好ましい。この理由は以下の通りである。
ねじの回転量を少なくするためにねじの多条数化やねじピッチを大きくするにつれて、ねじのリード角が大きくなる。ねじのリード角が大きくなりすぎると曲げや引張力など継手部軸方向に引張力が作用する場合に緩んでしまい力の伝達機能が得られないことが考えられる。
<Screw lead angle θ>
The screw lead angle θ is preferably set so as to satisfy θ ≦ 5.7 °. The reason is as follows.
In order to reduce the amount of screw rotation, the lead angle of the screw increases as the number of threads increases or the screw pitch increases. If the lead angle of the screw becomes too large, it is considered that when a tensile force such as bending or tensile force is applied in the axial direction of the joint, the screw is loosened and a force transmission function cannot be obtained.
ここで継手部軸方向に引張力が作用する場合のねじ山部での力の分力を模式的に図８に示す。
ねじ山の接触部どうしの摩擦係数は、ねじの材料である鋼材どうしの摩擦係数μとしてμ≧0.10程度である。この摩擦係数を用いて、継手部軸方向に引張力が作用してもねじが動き出さないの条件としては、［ねじ山面どうしの摩擦抵抗力］≧［ねじ山平行方向への分力］であり、μ×Pcosθ≧Psinθとなる。
これより、μ≧sinθ／cosθ＝tanθとなり、μ＝0.1（潤滑材を塗布した金属面どおしの摩擦係数）とすると、0.1≧tanθとなり、θ≦5.71°以下であれば良いことが分かる。
つまり、リード角がθ≦5.7°を満足すれば継手軸方向に引張力が作用する場合でも継手の締結は保持され、構造体鋼管用平行ねじ継手１としての性能が保持されることが可能となる。
Here, FIG. 8 schematically shows the force component at the thread portion when the tensile force acts in the joint portion axial direction.
The friction coefficient between the contact portions of the screw thread is about μ ≧ 0.10 as the friction coefficient μ between the steel materials as the screw materials. Using this coefficient of friction, the condition that the screw does not start even when a tensile force is applied in the axial direction of the joint is [Friction resistance between thread surfaces] ≧ [Component force in the thread parallel direction] Yes, and μ × Pcosθ ≧ Psinθ.
From this, μ ≧ sinθ / cosθ = tan θ, and if μ = 0.1 (coefficient of friction through the metal surface coated with the lubricant), 0.1 ≧ tan θ, and θ ≦ 5.71 ° or less is sufficient. .
In other words, if the lead angle satisfies θ ≦ 5.7 °, the joint fastening is maintained even when a tensile force acts in the joint axial direction, and the performance as the parallel threaded joint 1 for a structural steel pipe can be maintained. Become.
もっとも、θ＞5.7°の場合であっても継手管軸方向に引張力が作用した場合にねじが外れようとする力に応じて必要耐力を有する逆回転防止金具が具備されていれば、ねじは外れることなくねじ山を介して力の伝達が期待できる。
逆回転防止金具としては、主にピンやボルトなどの丸型鋼材が取付易く適しているが、マシンキーに見られるような角型鋼材を用いても良い。
However, even if θ> 5.7 °, if a reverse rotation prevention metal fitting having the necessary proof strength is provided according to the force to be removed when a tensile force is applied in the joint pipe axial direction, The force can be transmitted through the thread without disengagement.
As the reverse rotation preventing metal fitting, a round steel material such as a pin or a bolt is suitable for easy mounting, but a square steel material as seen in a machine key may be used.
＜継手管の最大板厚について＞
構造体鋼管用平行ねじ継手に用いる継手管の最大板厚として、杭径の2.5〜5.0%が望ましい。これは、ねじを鋼管への溶接取付時の変形抑止効果や運搬時の真円度変形抑止効果から少なくとも2.5%程度あることが望ましく、一方で板厚があまり厚くなりすぎると杭径に対してねじの嵌合位置での径が小さくなりねじ山に偏心荷重が作用しやすくなることや、杭内径側への突出が大きくなりすぎると鋼管中空部にオーガスクリューなどの施工治具の挿入時の支障になってしまうため、杭径の5.0%以下にとどめておくことが良い。
・ねじ継手板厚を杭径の2.5〜5.0%とする場合、鋼管としては、主に引張強さTS=400〜590N/mm2級の鋼管を対象とする場合、ねじ継手に用いる鋼材についてはTS=780N/mm2以上の強度を有する材料を用いる
<Maximum thickness of joint pipe>
The maximum thickness of the joint pipe used for the parallel thread joint for structural steel pipes is preferably 2.5 to 5.0% of the pile diameter. This is preferably at least about 2.5% from the effect of suppressing deformation when welding the screw to the steel pipe and the effect of suppressing roundness deformation during transportation. On the other hand, if the plate is too thick, The diameter at the screw fitting position becomes small and an eccentric load tends to act on the screw thread, or if the protrusion toward the inner diameter side of the pile becomes too large, it is difficult to insert an auger screw or other construction jig into the hollow part of the steel pipe. It will be a hindrance, so it is better to keep it below 5.0% of the pile diameter.
・ When the threaded joint thickness is 2.5 to 5.0% of the pile diameter, the steel pipe is mainly used for steel pipes with tensile strength TS = 400 to 590 N / mm 2 class. Use a material with strength of TS = 780N / mm 2 or more
＜ねじ山形状＞
ねじ山の形状に関しては、力の伝達性を考慮して台形ねじもしくは角ねじが望ましい。また、ねじ山高さhとねじ底幅Bとの関係は、h≦2Bを満足することが望ましい。
<Thread shape>
Regarding the shape of the thread, a trapezoidal screw or a square screw is desirable in consideration of force transmission. Further, it is desirable that the relationship between the thread height h and the thread bottom width B satisfies h ≦ 2B.
１ 構造体鋼管用平行ねじ継手
３ 雄継手
５ 雌継手
７ 雄ねじ山
９ 雌ねじ山
１１ ピン挿入孔
２１ 杭打機
２３ ねじ継手
２５ ねじ継手付鋼管
２７ 回転バンド
２９ 回転棒
３１ ねじ継手（１条ねじで６山）
３３ 雄継手
３５ 雌継手
３７ 雄ねじ山
３９ 雌ねじ山
４１ ねじ継手（４条ねじで２山）
DESCRIPTION OF SYMBOLS 1 Parallel threaded joint for structural steel pipes 3 Male joint 5 Female joint 7 Male thread 9 Female thread 11 Pin insertion hole 21 Pile driver 23 Screw joint 25 Steel pipe with thread joint 27 Rotating band 29 Rotating rod 31 Thread joint (1 thread 6 mountains)
33 Male joint 35 Female joint 37 Male thread 39 Female thread 41 Threaded joint (2 threads with 4 threads)
Claims (5)
嵌合するねじ山数Ｍとねじ条数Ｎとの関係がＭ／Ｎ≦0.5に設定されると共に、Ｍ≦４であり、嵌合するねじ山数がＭと異なる範囲が、継手周方向長さに対して所定割合以下に設定されていることを特徴とする構造体鋼管用平行ねじ継手。 A parallel threaded joint for structural steel pipes used for joining steel pipes constituting the structural body,
The relationship between the number of threads M to be fitted and the number of threads N is set to M / N ≦ 0.5, and M ≦ 4. A parallel threaded joint for structural steel pipes, characterized in that it is set to a predetermined ratio or less with respect to the thickness.
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| US4846508A (en) * | 1987-12-16 | 1989-07-11 | Vetco Gray Inc. | Tubular connector system |
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| JPH1143938A (en) * | 1997-07-29 | 1999-02-16 | Kubota Corp | Steel pipe pile connection part |
| KR20150066557A (en) * | 2012-10-01 | 2015-06-16 | 엔테그리스, 아이엔씨. | Connection system and method |
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