JPH06270072A - Fastening control method for special joint having shoulder seal - Google Patents
Fastening control method for special joint having shoulder sealInfo
- Publication number
- JPH06270072A JPH06270072A JP6647493A JP6647493A JPH06270072A JP H06270072 A JPH06270072 A JP H06270072A JP 6647493 A JP6647493 A JP 6647493A JP 6647493 A JP6647493 A JP 6647493A JP H06270072 A JPH06270072 A JP H06270072A
- Authority
- JP
- Japan
- Prior art keywords
- torque
- special joint
- seal
- pipe
- shoulder
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Pending
Links
Landscapes
- Details Of Spanners, Wrenches, And Screw Drivers And Accessories (AREA)
- Non-Disconnectible Joints And Screw-Threaded Joints (AREA)
Abstract
Description
【０００１】[0001]
【産業上の利用分野】本発明は例えば油井管の連結に用
いられる管端面との接触によりシール作用をなすショル
ダシールを有する特殊継手の締付制御方法に関する。BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a tightening control method for a special joint having a shoulder seal that performs a sealing action by contact with an end surface of a pipe used for connecting oil country tubular goods.
【０００２】[0002]
【従来の技術】例えば石油採掘の現場において用いられ
る油井管用の管継手には、管内の高圧に対する高い密封
性能が要求されるとともに、多数本の連結に耐えるだけ
の十分な強度が要求される。そこで従来から、図３に示
すようなねじ込み式の特殊継手１が用いられている。2. Description of the Related Art For example, a pipe joint for an oil well pipe used in a field of oil mining is required to have high sealing performance against high pressure in the pipe and sufficient strength to endure a large number of connections. Therefore, conventionally, a screw-in type special joint 1 as shown in FIG. 3 has been used.
【０００３】この特殊継手１は、両端からそれぞれ所定
の長さの雌ねじ部10, 10をその内周に形成してなる円筒
形の部材であり、雌ねじ部10, 10のさらに奥側にはシー
ル面11, 11と、このシール面11, 11に連なり特殊継手１
の軸心線に略直交するショルダ面12, 12とが形成されて
いる。一方、この特殊継手１にて連結される管２の管端
部には、この管２の軸心線に略直交するシール端面22
と、このシール端面22の外周側に連なり前記シール面11
と対応するシール面21と、このシール面21に連なり前記
雌ねじ部10に対応する雄ねじ部20とが形成されている。The special joint 1 is a cylindrical member having internal thread portions 10 and 10 each having a predetermined length formed from both ends thereof, and a seal is provided on the inner side of the internal thread portions 10 and 10. Surface 11, 11 and special joint 1 connected to this sealing surface 11, 11.
Shoulder surfaces 12, 12 that are substantially orthogonal to the axis of the. On the other hand, at the pipe end portion of the pipe 2 connected by the special joint 1, a seal end surface 22 that is substantially orthogonal to the axial center line of the pipe 2 is provided.
And the seal surface 11 connected to the outer peripheral side of the seal end surface 22.
A seal surface 21 corresponding to the above and a male screw portion 20 connected to the seal surface 21 and corresponding to the female screw portion 10 are formed.
【０００４】そして特殊継手１と管２との接合は、特殊
継手１の内側に管２の端部を嵌合した後、特殊継手１を
軸心回りに回転させて、管２の雄ねじ部20に特殊継手１
の雌ねじ部10をねじ込むことによりなされる。図４はこ
のねじ込み後の締結部の拡大断面図である。この図に示
すように、正しくねじ込みがなされた場合には、特殊継
手１内周のシール面11と管２外周のシール面21とが全長
にわたって密着して円周シール部が形成され、さらに特
殊継手１のショルダ面12に管２のシール端面22が突き当
てられて密着してショルダシール部が形成されており、
両シール部でのシール作用により高い密封性能が得られ
るのである。The special joint 1 and the pipe 2 are joined by fitting the end of the pipe 2 inside the special joint 1 and then rotating the special joint 1 around the axis to make the male threaded portion 20 of the pipe 2. Special fitting 1
This is done by screwing the female screw portion 10 of. FIG. 4 is an enlarged sectional view of the fastening portion after the screwing. As shown in this figure, when screwed in correctly, the seal surface 11 on the inner circumference of the special joint 1 and the seal surface 21 on the outer circumference of the pipe 2 are in close contact with each other to form a circumferential seal portion. The seal end surface 22 of the pipe 2 is abutted against the shoulder surface 12 of the joint 1 to be in close contact therewith to form a shoulder seal portion,
A high sealing performance can be obtained by the sealing action at both sealing portions.
【０００５】上記のような特殊継手１への管２の締結
は、特殊継手１を保持して軸心回りに回転させる回転チ
ャックとを同心上に備えた締結機（図示せず）により行
われるが、このとき回転チャックを介して特殊継手１に
加えられる締付けトルクを検出し、この検出結果が所定
の上限トルクに達する直前に締結機の動作を停止してね
じ込みを終了することにより、特殊継手１と管２とが前
記上限トルクに近い所定範囲内の締付トルク下にて締結
されるようになしてある。Fastening of the pipe 2 to the special joint 1 as described above is performed by a fastening machine (not shown) concentrically provided with a rotary chuck that holds the special joint 1 and rotates about the axis. However, at this time, the tightening torque applied to the special joint 1 via the rotary chuck is detected, and immediately before the detection result reaches a predetermined upper limit torque, the operation of the fastening machine is stopped and the screwing is completed, so that the special joint is 1 and the pipe 2 are fastened under a tightening torque within a predetermined range close to the upper limit torque.
【０００６】図５は、締結機の動作中に特殊継手１に加
えられる締付トルクの変化状態を示す特性図である。締
付けが正しくなされている場合は、締付トルクはまず特
殊継手１の雌ねじ部10と管２の雄ねじ部20との嵌め合わ
せ部の干渉が始まる点Ｓから点Ａまでの初期においては
ターン数の増加に伴って漸増する領域（以下、ショルダ
トルク域という）を経て、そのＡ点から特殊継手１のシ
ョルダ面12と管２のシール端面22の接触、すなわちショ
ルダシール部の干渉が始まると急増して最終締付トルク
Ｐに至るショルダシール部の領域（以下、デルタトルク
域という）まで変化する。FIG. 5 is a characteristic diagram showing a change state of the tightening torque applied to the special joint 1 during the operation of the fastening machine. If the tightening is correct, the tightening torque is the number of turns in the initial stage from the point S to the point A at which the interference of the fitting portion between the female screw portion 10 of the special joint 1 and the male screw portion 20 of the pipe 2 starts. After passing through a region that gradually increases with the increase (hereinafter referred to as the shoulder torque region), the contact surface between the shoulder surface 12 of the special joint 1 and the seal end surface 22 of the pipe 2, that is, when the interference of the shoulder seal portion starts, increases sharply from point A. To the final tightening torque P (hereinafter referred to as the delta torque range).
【０００７】この変曲点Ａにおけるショルダトルク域か
らデルタトルク域への転換は、特殊継手１のショルダ面
12に管２のシール端面22が突き当たった時点において生
じるものであり、特殊継手１のシール性はこの変曲点Ａ
以後すなわちショルダシール部の干渉以後のデルタトル
ク域に依存するため、これをいかに制御するかがシール
性向上の要点とされている。The conversion from the shoulder torque range to the delta torque range at the inflection point A is performed by the shoulder surface of the special joint 1.
This occurs when the seal end surface 22 of the pipe 2 abuts on the pipe 12, and the sealing performance of the special joint 1 depends on this inflection point A.
After that, that is, since it depends on the delta torque region after the interference of the shoulder seal portion, how to control this is a key point for improving the sealing performance.
【０００８】このデルタトルク域を制御する方法として
は、例えば特開昭63−229272号公報には締付トルク値を
微小時間毎にサンプリングし、一定時間前後のサンプリ
ングトルク値の差を演算し、演算したトルク値の差と予
め設定した設定値とを比較し、演算したトルク値の差が
設定値を超えたときの締付トルクによってショルダシー
ル部とし、それ以後のデルタトルクを制御する方法が提
案されている。As a method of controlling the delta torque range, for example, in Japanese Patent Laid-Open No. 63-229272, the tightening torque value is sampled at every minute time, and the difference between the sampling torque values before and after a fixed time is calculated, The method of comparing the difference between the calculated torque values and the preset value and setting the shoulder seal part by the tightening torque when the difference between the calculated torque values exceeds the set value and controlling the delta torque after that is the method. Proposed.
【０００９】一方、上記特開昭63−229272号の方法では
トルクの微小な変動のため微小時間のトルク増分のばら
つきが大きくショルダシール部の検出精度が劣る点を改
善すべく、特開平４− 83988号公報では締付トルクおよ
びターン数を所定時間毎にサンプリングして相互に対応
させて順次記憶し、締結終了時点における最終のターン
数から所定数だけ少ないターン数の範囲内にある記憶デ
ータのそれぞれに対して差分演算を行い、得られた差分
値中の最大値に所定の係数を乗じて基準値を定めるとと
もに、前記差分値を前記記憶の順と逆に調べて前記基準
値を最初に下回るものを取り出し、これに対応する記憶
データを変曲点での締付トルクおよびターン数とする、
すなわち締付完了後においてショルダシール干渉以後の
トルクカーブを調べることによりショルダシール部を検
出する方法である。On the other hand, in the method of the above-mentioned Japanese Patent Laid-Open No. 229272/1988, in order to improve the point that the accuracy of detecting the shoulder seal portion is poor due to the large variation of the torque increment in a minute time due to the minute fluctuation of the torque, Japanese Patent Laid-Open Publication No. In the publication No. 83988, the tightening torque and the number of turns are sampled at predetermined time intervals and stored in correspondence with each other, and the stored data within the range of the number of turns smaller than the final number of turns at the end of the fastening by a predetermined number are stored. The difference calculation is performed on each of them, and a reference value is determined by multiplying the maximum value among the obtained difference values by a predetermined coefficient, and the difference value is examined in the reverse order of the memory and the reference value is first determined. Take out the one that is lower than this, and use the stored data corresponding to this as the tightening torque and the number of turns at the inflection point,
That is, it is a method of detecting the shoulder seal portion by checking the torque curve after the interference of the shoulder seal after completion of tightening.
【００１０】[0010]
【発明が解決しようとする課題】しかしながら、上記し
た従来技術において、前者の特開昭63−229272号の方法
の場合は、正確にショルダシール部を検知し得たとして
もそこで定義されているデルタトルクはシール干渉に伴
うトルクとねじ干渉のトルクが合わさったものであっ
て、真にシール性を左右するショルダシール部トルクが
得られないという問題がある。However, in the above-mentioned prior art, in the case of the former method of JP-A-63-229272, even if the shoulder seal portion can be accurately detected, the delta defined therein is defined. The torque is the sum of the torque due to the seal interference and the torque due to the screw interference, and there is a problem that the shoulder seal portion torque that truly affects the sealability cannot be obtained.
【００１１】一方、後者の特開平４− 83988号の方法を
用いると確かにショルダシール部の検出精度は高まる
が、締付完了後にショルダシール部を検出することにな
るため、デルタトルクの制御に採用することができない
という欠点がある。本発明は、上記のような従来技術の
有する課題を解決したショルダシールを有する特殊継手
の締付制御方法を提供することを目的とする。On the other hand, when the latter method of Japanese Patent Laid-Open No. 4-83988 is used, the accuracy of detecting the shoulder seal portion is certainly improved, but since the shoulder seal portion is detected after the completion of tightening, the delta torque is controlled. It has the drawback that it cannot be adopted. It is an object of the present invention to provide a tightening control method for a special joint having a shoulder seal, which solves the problems of the prior art as described above.
【００１２】[0012]
【課題を解決するための手段】本発明は、管端面との接
触によりシール作用をなすショルダ面をその内面に有す
る特殊継手を所定の締付トルクにて管にねじ込み締付け
するに際し、ねじ嵌め合わせ部のトルク変化を予測し、
その予測値と実トルクとの差分演算を行ってシール部の
有効トルクを求め、この有効トルクが予め定められた上
限設定値以上になった時点で締付けを停止することを特
徴とするショルダシールを有する特殊継手の締付制御方
法である。SUMMARY OF THE INVENTION According to the present invention, a special joint having a shoulder surface on its inner surface, which has a sealing action by contact with a pipe end surface, is screwed into a pipe with a predetermined tightening torque and tightened by screw fitting. Predict the torque change of the part,
The shoulder seal is characterized in that the difference between the predicted value and the actual torque is calculated to obtain the effective torque of the seal portion, and the tightening is stopped when this effective torque exceeds a predetermined upper limit set value. It is a tightening control method for the special joints that it has.
【００１３】[0013]
【作 用】以下に、本発明のショルダシール部トルク検
出および締付制御の手順について図１を用いて説明す
る。 まず、嵌め合わせの初期のショルダトルク域でのトル
クが漸増するトルク立ち上がり時において、図２に示す
ように、測定された実トルクＴR1を用いてターン数ｎ1
から任意のターン数ｎ2 までの間にねじ嵌め合わせトル
クＴP の予測値を式ＴP ＝ｆ（ｎ）を重回帰することに
よって求める。 引き続きターン数ｎ2 以後の実トルクＴR2を測定す
る。 実トルクＴR2とトルク予測値ＴP とのトルク偏差ΔＴ
（＝ＴR −ＴP ）をシール部のシールトルクの有効トル
クとしてリアルタイムに求める。 このトルク偏差ΔＴが予め定められた最適値ΔＴopt
になったかどうかを判定する。 トルク偏差ΔＴが最適値ΔＴopt 以上になった時点
で、実トルクＴR2が最終締付トルクに至ったと判定して
締付けを停止する。[Operation] Hereinafter, the procedure of torque detection and tightening control of the shoulder seal portion of the present invention will be described with reference to FIG. First, when the torque rises gradually in the shoulder torque region in the initial stage of fitting, as shown in FIG. 2, the measured actual torque T R1 is used to determine the number of turns n 1
To the arbitrary number of turns n 2 the predicted value of the screw fitting torque T P is obtained by performing multiple regression of the formula T P = f (n). Continue to measure the number of turns n 2 after the actual torque T R2. Torque deviation ΔT between actual torque T R2 and predicted torque value T P
Determining in real time (= T R -T P) as an effective torque of the seal torque of the seal portion. This torque deviation ΔT is a predetermined optimum value ΔT opt
It is determined whether or not. When the torque deviation ΔT becomes equal to or more than the optimum value ΔT opt , it is determined that the actual torque T R2 has reached the final tightening torque, and the tightening is stopped.
【００１４】[0014]
【実施例】サイズ177.8mm φ×29ＬＢＳの油井管にショ
ルダシールを有する規格ＡＰＩ５ＣＴ−Ｌ80の特殊継手
を接続する際に、本発明を適用した。この特殊継手の締
付状態を事前に調査したところ、変曲点Ａにおけるター
ン数ｎ3 は0.4 〜0.6 ターンであり、最終締付トルクで
のターン数ｎ4 とｎ3 との差（ｎ4 −ｎ3 ）は0.03〜0.
05ターンであった。このときのシールトルクΔＴの最適
値ΔＴopt は1500kg・m であり、締付速度は６rpm とし
た。[Example] The present invention was applied when a special API5CT-L80 special joint having a shoulder seal was connected to an oil well pipe of size 177.8 mm φ × 29 LBS. When the tightened state of this special joint was investigated in advance, the number of turns n 3 at the inflection point A was 0.4 to 0.6, and the difference between the number of turns n 4 and n 3 at the final tightening torque (n 4 -N 3 ) is 0.03 to 0.
It was 05 turns. The optimum value ΔT opt of the seal torque ΔT at this time was 1500 kg · m, and the tightening speed was 6 rpm.
【００１５】そこで、ねじ嵌め合わせトルクＴP を予測
するに当たり、ターン数ｎ1 ＝0.05ターンからターン数
ｎ2 ＝0.25ターンまでの間に0.01ターン毎に計20点のサ
ンプリングトルクを用いて締付途中においてただちに回
帰計算を行ったところ、ＴP＝ 860ｎ＋20なる直線近似
を行うことができた。ここで、式中の＋20kg・m はグラ
フにトルクを表示し始める値である。なお、この直線近
似による誤差は0.2 ％程度である。Therefore, in predicting the screw fitting torque T P , tightening is performed using a total of 20 sampling torques every 0.01 turns from the number of turns n 1 = 0.05 turns to the number of turns n 2 = 0.25 turns. When a regression calculation was performed immediately on the way, a linear approximation of T P = 860n + 20 could be performed. Here, + 20kg · m in the equation is the value at which the torque starts to be displayed on the graph. The error due to this linear approximation is about 0.2%.
【００１６】ついで、ターン数ｎ2 の0.05ターン後すな
わちｎ3 ＝0.3 ターンで予測値を計算終了し、それ以後
実トルクＴR2との差ΔＴを計算開始し、ｎ4 ＝0.55ター
ンで最適値ΔＴopt を超えたところで締結作業を終了し
た。その結果シールトルク値の予測誤差が従来例の２〜
３％に対し0.3 ％と大幅に向上し、シール性能の向上を
図ることができた。Then, after 0.05 turns of the number of turns n 2 , that is, after n 3 = 0.3 turns, the calculation of the predicted value is completed, and after that, the calculation of the difference ΔT from the actual torque T R2 is started, and the optimum value is obtained at n 4 = 0.55 turns. The fastening work was completed when ΔT opt was exceeded. As a result, the prediction error of the seal torque value is 2 to 2 of the conventional example.
This was a significant improvement of 0.3% from 3%, and the sealing performance could be improved.
【００１７】[0017]
【発明の効果】以上説明したように、本発明によれば、
ねじ嵌め合わせ部のトルク変化を予測して、その予測値
と実トルクとの差をシール部の有効トルクとして、この
有効トルクを用いて特殊継手の締付制御を行うようにし
たので、シールトルク値の予測誤差を大幅に低減するこ
とが可能となり、特殊継手のシール性能を大幅に高める
ことが可能となり、製品の信頼性の向上に大いに寄与す
る。As described above, according to the present invention,
By predicting the torque change of the screw fitting part and using the difference between the predicted value and the actual torque as the effective torque of the seal part, the effective torque is used for tightening control of the special joint. It is possible to greatly reduce the prediction error of the value, and it is possible to greatly improve the sealing performance of the special joint, which greatly contributes to the improvement of product reliability.
【図１】本発明のショルダシール部トルク検出および締
付制御の手順を示す流れ図である。FIG. 1 is a flow chart showing a procedure of torque detection and tightening control of a shoulder seal portion of the present invention.
【図２】本発明を適用したときのターン数とトルクおよ
びシールトルクの関係を示す特性図である。FIG. 2 is a characteristic diagram showing the relationship between the number of turns and torque and seal torque when the present invention is applied.
【図３】特殊継手および管の従来例を示す断面図であ
る。FIG. 3 is a cross-sectional view showing a conventional example of a special joint and a pipe.
【図４】特殊継手および管の締結部の拡大断面図であ
る。FIG. 4 is an enlarged cross-sectional view of a special joint and a fastening portion of a pipe.
【図５】締結機の動作中に特殊継手に加えられる締付ト
ルクの変化状態を示す特性図である。FIG. 5 is a characteristic diagram showing a change state of the tightening torque applied to the special joint during the operation of the fastening machine.
１ 特殊継手 ２ 管 10 雌ねじ部 11 シール面 12 ショルダ面 20 雄ねじ部 21 シール面 22 シール端面 Ａ 変曲点 1 Special joint 2 Pipe 10 Female thread 11 Sealing surface 12 Shoulder surface 20 Male thread 21 Sealing surface 22 Sealing end surface A Inflection point
Claims (1)
すショルダ面をその内面に有する特殊継手を所定の締付
トルクにて管にねじ込み締付けするに際し、ねじ嵌め合
わせ部のトルク変化を予測し、その予測値と実トルクと
の差分演算を行ってシール部の有効トルクを求め、この
有効トルクが予め定められた上限設定値以上になった時
点で締付けを停止することを特徴とするショルダシール
を有する特殊継手の締付制御方法。1. When a special joint having a shoulder surface that acts as a seal by contact with the pipe end face is screwed into a pipe with a predetermined tightening torque and tightened, a torque change of a screw fitting portion is predicted, The shoulder seal is characterized in that the difference between the predicted value and the actual torque is calculated to obtain the effective torque of the seal portion, and the tightening is stopped when this effective torque exceeds a predetermined upper limit set value. Tightening control method for special joints.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP6647493A JPH06270072A (en) | 1993-03-25 | 1993-03-25 | Fastening control method for special joint having shoulder seal |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP6647493A JPH06270072A (en) | 1993-03-25 | 1993-03-25 | Fastening control method for special joint having shoulder seal |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| JPH06270072A true JPH06270072A (en) | 1994-09-27 |
Family
ID=13316824
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP6647493A Pending JPH06270072A (en) | 1993-03-25 | 1993-03-25 | Fastening control method for special joint having shoulder seal |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPH06270072A (en) |
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2010255710A (en) * | 2009-04-23 | 2010-11-11 | Jfe Steel Corp | Method of tightening special screw joint for oil well pipe |
| JP2016121486A (en) * | 2014-12-25 | 2016-07-07 | 株式会社大林組 | Method for managing jointing of steel-pipe column by screw-type mechanical joint |
-
1993
- 1993-03-25 JP JP6647493A patent/JPH06270072A/en active Pending
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2010255710A (en) * | 2009-04-23 | 2010-11-11 | Jfe Steel Corp | Method of tightening special screw joint for oil well pipe |
| JP2016121486A (en) * | 2014-12-25 | 2016-07-07 | 株式会社大林組 | Method for managing jointing of steel-pipe column by screw-type mechanical joint |
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