JPH0326431A - Tightening method and device - Google Patents
Tightening method and deviceInfo
- Publication number
- JPH0326431A JPH0326431A JP16308089A JP16308089A JPH0326431A JP H0326431 A JPH0326431 A JP H0326431A JP 16308089 A JP16308089 A JP 16308089A JP 16308089 A JP16308089 A JP 16308089A JP H0326431 A JPH0326431 A JP H0326431A
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- Prior art keywords
- motor
- screw
- torque
- tightening
- detection means
- 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.)
- Granted
Links
- 238000000034 method Methods 0.000 title claims description 7
- 230000001133 acceleration Effects 0.000 claims abstract description 17
- 238000001514 detection method Methods 0.000 claims abstract description 14
- XEEYBQQBJWHFJM-UHFFFAOYSA-N Iron Chemical compound [Fe] XEEYBQQBJWHFJM-UHFFFAOYSA-N 0.000 description 2
- 238000004458 analytical method Methods 0.000 description 2
- 238000004364 calculation method Methods 0.000 description 2
- 230000007423 decrease Effects 0.000 description 2
- 238000010586 diagram Methods 0.000 description 2
- 230000000694 effects Effects 0.000 description 2
- 238000012986 modification Methods 0.000 description 2
- 230000004048 modification Effects 0.000 description 2
- 201000004569 Blindness Diseases 0.000 description 1
- 238000007796 conventional method Methods 0.000 description 1
- 238000005516 engineering process Methods 0.000 description 1
- 238000009434 installation Methods 0.000 description 1
- 229910052742 iron Inorganic materials 0.000 description 1
- 238000012544 monitoring process Methods 0.000 description 1
- 238000011160 research Methods 0.000 description 1
Landscapes
- Details Of Spanners, Wrenches, And Screw Drivers And Accessories (AREA)
Abstract
Description
【発明の詳細な説明】
［産業上の利用分野］
本発明はモータによりねじを回転させるこヒによりねじ
を締めるねじ締め方法及び袈置に関する。DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a screw tightening method for tightening a screw using an iron that rotates the screw using a motor, and to a shank installation.
時計、カメラ等の精密機器、コンビエータ、ディスク装
註等の電子機器等の各種産業における組立て作業におい
て、ねじ締め作業はもつとも基本的ならのである。Screw tightening is a basic task in the assembly work of various industries such as precision equipment such as watches and cameras, and electronic equipment such as combiators and disk drives.
このねじ締め作業は以前は作業者が通常のドライバを用
いてねじをまわずことにより行われていた。しかし、近
年、作業の効率化の観点からモータによりねじをまわす
電動ドライバが多く用いられるようになっている．
ねじ締め作業において最も重要なことは、外力が加わっ
ても簡単には緩まない適切な締め付け力でねじ締めを行
うことにある．人手によりねじ締めを行う場合には、ど
の程度の力で締め付ければよいかを経験的に学び、熟練
者になれば極めて適切な締め付け力でねじ締め作業を行
うことができた．しかし２作業効率を一定程度以−Ｌ向
上させることはできなかった。Previously, this screw tightening work was performed by an operator turning the screws using an ordinary screwdriver. However, in recent years, electric screwdrivers that use motors to turn screws have come into widespread use in order to improve work efficiency. The most important thing in screw tightening work is to tighten the screws with an appropriate tightening force that will not easily loosen even when external force is applied. When manually tightening screws, we learned through experience how much force should be used to tighten them, and once we became experts, we were able to tighten the screws with extremely appropriate tightening force. However, it was not possible to improve the work efficiency beyond a certain level.
これに対し、電動ドライバを用いた場合には作業効率を
向上させることが期待できる．しかしながら、電動ドラ
イバで速く締めようとずると、ねじを強く締め過ぎて破
壊してしまう可能性があり、しかも、ね１′／の締め付
Ｇｌ力を一定値にするように制御しなければならない．
このため、従来の電動ドライバでは次のような種々の工
夫をしている，
モータの回転速度を遠くすると、わずかなタイミングの
ずれでもねじを締め過ぎて破壊してしまう．モータの慣
性モーメンｌ・が大きいほどねじを締め過ぎやすい．こ
のため、従来の電動ドライバではなるべく慣性モーメン
トの小さい小型のモータを用いるようにしている．
一方、ねじ締め作業におけるねじ締め力はかなり高いも
のが要求されている．このため、従来の電動ドライバで
は、ねじ締めを２段階で行うようにし、わじ締めの初期
段階では小さいモータ電流で比較的高速にモータを駆動
し、ねじ締めの最終段階ではモータ電流を大きくして所
望の大きな締め付け力になるような定電流制御に切り換
えて一定トルクで締め付けるようにしている。On the other hand, using an electric screwdriver can be expected to improve work efficiency. However, if you try to tighten it quickly with an electric screwdriver, there is a possibility that the screw will be over-tightened and destroyed.Moreover, the tightening Gl force of the thread 1'/ must be controlled to a constant value. ．． For this reason, conventional electric screwdrivers have been devised in various ways, such as the following: If the motor rotation speed is set too far, even a slight timing difference can lead to over-tightening of the screws and damage. The larger the moment of inertia l of the motor, the easier it is to overtighten the screws. For this reason, conventional electric screwdrivers use small motors with as small a moment of inertia as possible. On the other hand, considerably high screw tightening force is required for screw tightening work. For this reason, with conventional electric screwdrivers, screw tightening is performed in two stages, in which the motor is driven at relatively high speed with a small motor current in the initial stage of tightening, and the motor current is increased in the final stage of screw tightening. Then, the controller switches to constant current control to obtain a desired large tightening force, and tightens with a constant torque.
［゜発明が解決しようとする課題］
しかしながら、このような従来の電動ドライバの場合、
初期段階においてモータの回転速度を上げるとねじを締
め過ぎてしまうたぬ、ある程度以上には上げられないと
いう問題があった。しかし、作業効率を上げるためには
、ねじが＠座する前の初期段階でなるべく高速でねじを
回転させることが望ましい．したがって、従来は実験デ
ータをもとにして経験と勘により調整して、ねじを締め
過ぎない範囲でいかに高速に回転させるかを決定してい
た．しかも、締め付けるねじの種類により許容される回
転速度が異なるため、ねじ毎に手探りの状態で調整を行
う必要があり、作業効率を更に低下させていた．
本発明は上記事情を考慮してなされたもので、常に適切
な締め付け力で高速でｈじ締めを行う、二とができるね
じ締め方法及び装置を提供することを目的とする．
［課題を解決するための千段１
従来からねじ締めは経験と勘により行われており、ねじ
締めの力学的動作について本格的に解析したものはなく
、基本的にどのような運動方程式に基づいてねじ締めが
行われるかについては全く不明であった．
本願発明者はモータを用いたねじ締めについて力学的な
解析を行い、鋭意研究努力の結果、ねじ締め動作を適切
に表現した基本的な運動方程式を求めることに成功した
．すなわち、ねじ締め動作の基本的な運動方程式は次の
通りである．■・ｄ２θ／ｄｔ２＝−ｆ （θ）＋ｇ（
ｉ）ただし、■はモータにより回転する全体の慣性モー
メント、θはモータの回転角、ｆ（θ）はねじから反発
される抗力トルク、１はモータの電流値、ｇ（ｉ）はモ
ータの発生するモータトルクである．本発明はかかる運
動方程式に基づいてなされたものである．本発明の原理
を第１図を用いて説明する．
ねじ１は、モータ２により回転されるビット３により締
められる．回転角加速度検出手段４は、モータ２の回転
状態から回転角加速度ｄ２θ／ｄｔ２を常に検出してお
り、トルク検出手段５は、モータ２が発生するモータト
ルクｇ（ｉ｝を検出する．モータ駆動制御手段６は、回
転角加速度検出手段４からの回転角加速度ｄ２θ／ｄｔ
２ トルク検出手段５からのモータトルクｇ（ｉ）から
上述の運動方程式を変形した運動方程式ｆ（θ）＝−Ｉ
−ｄ２θ／ｄｔ２＋ｇ（ｉ）に基づいて、ねじの抗力ト
ルクｆ（θ）すなわち、ねじの締め付けトルクを演算し
、抗力トルクｆ（θ）が目標トルク値になった時点で停
止するようにモータ２を駆動制御する．
［作用］
本発明によれば、モータの駆動制御をねじ締めの運動方
程式に基づいて行うようにしているので、常にねじの抗
力トルクを正確に把握することができる．したがって、
抗力トルクが設定値になった時点でモータを停止させる
ようにすれば、常に正確な締め付けトルクでねじを締め
ることができる．［実施例］
本発明の一実施例によるねじ締め装置を第２図に示す．
本実施例では例えば直流モータ．１２を用いている．こ
のモータ１２の先端にはビット１４が取り付けられてお
り、このビット１４によりねじ１０が回転されて締めら
れる．
モータ１２の後部には回転角θを検出するために例えば
エンコーダ１６が取り付けられている．エンコーダ１６
は、モータ１２の回転軸に取り付けられた回転板に刻ま
れた格子を例えば光学的に読取り、モータ１２の回転角
θに応じたパルス信号を発生するものである．
エンコーダ１６からの回転角信号は微分回路１８により
時間ｔで微分され、回転角速度ｄθ／ｄｔ（回転角速度
ω〉が求められる．さらに、回転角速度信号は微分回路
２０により時間ｔで微分され、回転角加速度ｄ２θ／ｄ
ｔ”が求められる．微分回路２０により求められた回転
角加速度ｄ２θ／ｄｔ２は、慣性モーメントＩと乗算部
２２により乗算され、Ｉ−ｄ”θ／ｄｔ２が求められる
．慣性モーメント■はモータ１２により回転される全体
の慣性モーメントであり、正確にはモータ１２の慣性モ
ーメン゜トの他にビット１４やねじ１０の慣性モーメン
トも含むものである．しかしながら、直径が小さい部材
の慣性モーメントは無視できるほど小さいので、実際に
は慣性モーメント■はモータ１２の慣性モーメントとし
て差支えない．したがって、ねじ１０やビット１４の種
類が異なっても慣性モーメントＩは同じである．乗算部
２４はモータ１２が発生するモータトルクｇ（ｉ）を演
算する．すなわち、直流モータ１２の場合、モータトル
クｇ（ｉ〉はモータ電流１にトルク定数ｋを掛けたもの
になることが知られているので、モータｌ２に供給され
ている電流１にモータ１２のトルク定数ｋを乗算して、
モータトルクｇ（ｉ）であるｋ−１を求める。[゜Problems to be solved by the invention] However, in the case of such a conventional electric screwdriver,
At the initial stage, there were problems in that increasing the motor's rotational speed would result in over-tightening the screws, and that it could not be increased beyond a certain level. However, in order to increase work efficiency, it is desirable to rotate the screw as fast as possible in the initial stage before it is seated. Therefore, in the past, adjustments were made based on experimental data, experience and intuition to determine how fast to rotate the screw without over-tightening it. Moreover, since the allowable rotational speed differs depending on the type of screw to be tightened, it is necessary to make adjustments for each screw by hand, further reducing work efficiency. The present invention has been made in consideration of the above circumstances, and an object thereof is to provide a screw tightening method and device that can perform two functions, such as always tightening screws at high speed with an appropriate tightening force. [1,000 Steps to Solving Problems Traditionally, screw tightening has been done based on experience and intuition, and there has been no full-scale analysis of the mechanical movement of screw tightening. It was completely unclear whether the screws would be tightened. The inventor of this application conducted a mechanical analysis of screw tightening using a motor, and as a result of intensive research efforts, succeeded in finding a basic equation of motion that appropriately expresses the screw tightening operation. In other words, the basic equation of motion for screw tightening operation is as follows. ■・d2θ/dt2=-f (θ)+g(
i) However, ■ is the overall moment of inertia rotated by the motor, θ is the rotation angle of the motor, f(θ) is the drag torque repelled from the screw, 1 is the motor current value, and g(i) is the motor generation This is the motor torque. The present invention was made based on this equation of motion. The principle of the present invention will be explained using Figure 1. The screw 1 is tightened by a bit 3 rotated by a motor 2. The rotational angular acceleration detection means 4 always detects the rotational angular acceleration d2θ/dt2 from the rotational state of the motor 2, and the torque detection means 5 detects the motor torque g(i} generated by the motor 2. Motor drive The control means 6 detects the rotational angular acceleration d2θ/dt from the rotational angular acceleration detection means 4.
2 Equation of motion f(θ)=-I which is a modification of the above equation of motion based on the motor torque g(i) from the torque detection means 5
-d2θ/dt2+g(i), calculate the drag torque f(θ) of the screw, that is, the tightening torque of the screw, and set the motor 2 to stop when the drag torque f(θ) reaches the target torque value. Drive and control. [Operation] According to the present invention, since the drive control of the motor is performed based on the equation of motion for screw tightening, the drag torque of the screw can be accurately grasped at all times. therefore,
By stopping the motor when the drag torque reaches the set value, you can always tighten screws with the correct tightening torque. [Embodiment] Fig. 2 shows a screw tightening device according to an embodiment of the present invention. In this embodiment, for example, a DC motor is used. 12 is used. A bit 14 is attached to the tip of this motor 12, and the screw 10 is rotated and tightened by this bit 14. For example, an encoder 16 is attached to the rear of the motor 12 to detect the rotation angle θ. encoder 16
The system reads, for example, optically a grating carved on a rotary plate attached to the rotating shaft of the motor 12, and generates a pulse signal corresponding to the rotation angle θ of the motor 12. The rotation angle signal from the encoder 16 is differentiated by the time t by the differentiating circuit 18, and the rotation angular velocity dθ/dt (rotation angular velocity ω) is determined.Furthermore, the rotation angular velocity signal is differentiated by the differentiator 20 by the time t, and the rotation angle Acceleration d2θ/d
The rotational angular acceleration d2θ/dt2 obtained by the differentiating circuit 20 is multiplied by the moment of inertia I by the multiplier 22, and I-d”θ/dt2 is obtained. The moment of inertia (2) is the moment of inertia of the entire rotation by the motor 12, and more precisely, it includes the moment of inertia of the bit 14 and screw 10 in addition to the moment of inertia of the motor 12. However, since the moment of inertia of a member with a small diameter is negligibly small, the moment of inertia (2) can actually be used as the moment of inertia of the motor 12. Therefore, even if the types of screws 10 and bits 14 are different, the moment of inertia I is the same. The multiplier 24 calculates the motor torque g(i) generated by the motor 12. In other words, in the case of the DC motor 12, it is known that the motor torque g(i) is the motor current 1 multiplied by the torque constant k. Multiply by constant k,
Find k-1, which is the motor torque g(i).
減算部２６は、乗算部２４からのモータトルクｇ （ｉ
）であるｋ−１から乗算部２２からのＩ・ｄ２θ／ｄｔ
’を減算して、抗力トルクｆ（θ）ｆ（θ）＝−Ｉ・ｄ
２θ／ｄｔ２＋ｋ・１を求める．
比較部２８は、減算部２６により求められｔ：抗力トル
クｆ（ρ〉を設定された抗力１・ルク値ｆ０と比較ずる
．抗力トルク値ｆ。は可変抵抗器により槽或されたトル
ク設定部２９により夕１部から自由に設定するこヒがで
きる。The subtraction unit 26 calculates the motor torque g (i
) from k-1 to I・d2θ/dt from the multiplier 22
', drag torque f(θ) f(θ) = -I・d
Find 2θ/dt2+k・1. The comparator 28 compares the drag torque f(ρ) obtained by the subtractor 26 with the set drag torque value f0.The drag torque value f is determined by the torque setting section set by the variable resistor. 29 allows you to freely set the settings from the first part of the evening.
比Ｉｌ１部２８により抗力ｌ−ルクｆ（θ）が抗力トル
ク鋏ｆｏになったことが検知されると，ただちに検知信
号をモータ電流切換スイッチ３０に出力する。なお、抗
力トルクｉｆ。ｃｉ最終的なわじ締め時における締め付
Ｇｔ ＋−・ルクとして定められた目誤トルクｉｌｏよ
りも少し低い鎖にするのが望ましい．こｔｔは、実際に
はモータ１２をＯ秒メは十分短い時間で浄止できないた
めである．
モータ電流切換スイッチ３０は、わじ１０を締める方向
にモータ１２を回転さぜるための定速回転制御部３４か
ら出力されるモータ電流と、逆方向のブレーキ電流１８
εを切り換えて、モータ駆動部３２に供給ずる。定速同
転制御部３４は指示回転角速度ω０でモータ１２を定速
回転させるための電流を出力するもので、定速回転制御
時のモ一，、夕電流は最大モータ雷流１ｌＩで制限され
、不必要な締めつけトルクを生じない土うにしている。When the ratio Il1 section 28 detects that the drag force l-rook f(θ) has become the drag force torque scissors fo, it immediately outputs a detection signal to the motor current changeover switch 30. In addition, the drag torque if. ci It is desirable to use a chain that is slightly lower than the estimated tightening torque ilo, which is determined as the final tightening Gt +-·lux. This is because the motor 12 cannot actually be cleaned in a sufficiently short time of 0 seconds. The motor current changeover switch 30 controls the motor current output from the constant speed rotation control unit 34 for rotating the motor 12 in the direction of tightening the brake 10, and the brake current 18 in the opposite direction.
ε is switched and supplied to the motor drive section 32. The constant speed simultaneous rotation control unit 34 outputs a current for rotating the motor 12 at a constant speed at a commanded rotational angular velocity ω0, and the motor current during constant speed rotation control is limited by the maximum motor current 1lI. , so that unnecessary tightening torque is not generated.
最初は、定速回転制ａｉ＋部３４からのモータ電流１８
をモータ駆動部３２に供給してモータ１２を回転させる
が、比較部２８が抗力トルクｒ（θ）が設定値ｆ．にな
ったこと検出する辷、モータ駆動部３２にブレーキ電流
ｉゆを供給してモータ１２にブレーキ李かける。Initially, the motor current 18 from the constant speed rotation control ai+ section 34
is supplied to the motor drive unit 32 to rotate the motor 12, but the comparison unit 28 determines that the drag torque r(θ) is the set value f. When it is detected that the motor 12 has reached a certain position, a brake current i is supplied to the motor drive unit 32 to apply a brake to the motor 12.
モータ駆動部３２はモータ電流切換スイッチ３０からの
電流によりモータ１２を駆動ずると共に、四転角速度ｄ
θ／ｄｔが零になるとモータ１２への電流の供給を停止
ずる６
次に、第３図を用いて本実施例の動作を説明する。同図
（ａ）はモータ＠流１のタイムチャートであり、同図（
ｈ）はモータ１２の回転角速度ω（＝ｄθ／ ｄ ｔ
）のタイムチャーｌ一であり、同図（ｃ）はねじ１０の
抗力トルクｆ《θ）のタイムチャ−１〜である．
最初は、ねじ１０のねじ頭１０ａは着座しておらず、モ
ータ１２は定速回転制御部３４により定速回転制御され
ており、回転角速度ω０で回転！，て〜）る．この２＝
き、ねじ１０はまだ着座し７ていないので、その抗力１
・・ルクｆ（θ）槌、おねじ山とめねじ出との摩擦力の
みに起囚ずるものであるため、ほぼ一定の低い鉋である
．
′ｊａ座する直前から回転角速度ωが徐々に低くなろう
とし、定速囲転制御のためモータ電流１が大外くなるに
絆曳，１、抗力トルクｆ（θ）が大きくなる．、Ｌか［
７、モータ駆動部３２によるモータ雷流ｉは電流制’９
ｒ ｆｌＩ ｉ Ｒにより制限されているため、着廃す
ると凹転角遠度ωが急激に低くなり、抗力トルクｆ（／
Ｊ）ｉｆｉ急激に大きくなる。The motor drive section 32 drives the motor 12 with the current from the motor current changeover switch 30, and also controls the quadrilateral angular velocity d.
When θ/dt becomes zero, the supply of current to the motor 12 is stopped.6 Next, the operation of this embodiment will be explained using FIG. 3. Figure (a) is a time chart of motor @flow 1;
h) is the rotational angular velocity ω(=dθ/dt
) is the time chart l-1, and FIG. Initially, the screw head 10a of the screw 10 is not seated, and the motor 12 is controlled to rotate at a constant speed by the constant speed rotation control unit 34, and rotates at a rotational angular velocity ω0! , Te~)ru. This 2=
At this time, the screw 10 is not yet seated, so its resistance 1
... Luk f(θ) is a mallet, which is generated only by the frictional force between the male thread and the female thread, so it is a plane with an almost constant low value. The rotational angular velocity ω begins to gradually decrease from just before the motor is seated, and as the motor current 1 becomes much larger due to constant speed rotation control, the drag torque f(θ) increases. , L or [
7. The motor current i caused by the motor drive unit 32 is current controlled.
Since it is limited by r flI i R, when it is worn and discarded, the concave angle farness ω decreases rapidly, and the drag torque f(/
J) ifi increases rapidly.
抗力｝・ルクｆ（θ）がＩ）らかしめ設定された抗力ｌ
−ルク値ｆ。に達ずると、比較部２８からの信号により
モータ電流切換スイッヂ３０がブｌ／−４ｔａｉｌ１に
切換えられる。するとモータ駆動部３２は、モータ１２
に逆方向のブレーキ劃旧，を供給［７て急ブレーキをか
ける．
モータ１２が伜止して微分回路１８から出ｊｌされる四
転角速度ωが零になると、第３図（ａ）に示ずＪ：うに
モータ駆動部３２は直ちにブｌノ−キ電流を切る．
モータ１２のブレーキ期間も、モータ１２は回転ずるの
で、抗力トルクｆ（θ）は設定値ｆ。を超えて上昇し、
ほぼ締め・ＮＯ目標ｌ−ルク値Ｆ。に達しノ、：状態で
停止ずる。Drag}・Lux f(θ) is I) Drag force l set by tightening
- Luk value f. When the current is reached, the motor current changeover switch 30 is switched to BL/-4tail1 by a signal from the comparator 28. Then, the motor drive unit 32
7. Apply the brake suddenly in the opposite direction. When the motor 12 stops and the four-turn angular velocity ω output from the differentiating circuit 18 becomes zero, the motor drive section 32 immediately cuts off the electric current as shown in FIG. 3(a). ．． Since the motor 12 rotates during the braking period of the motor 12, the drag torque f(θ) is the set value f. rises above
Almost tightened/NO target l-lux value F. Reaching: To stop in a state.
このように本実施例によれば、ねじの抗力トルクを検出
しながらモータを駆動制御するようにしたので、抗力ト
ルクが設定鎮になった時点でモータを急停止させるよう
にすれば、所望の締めｆ−目ナトルクでｈじを締める、
二とができる。In this way, according to this embodiment, the drive of the motor is controlled while detecting the drag torque of the screw, so if the motor is suddenly stopped when the drag torque reaches the set point, the desired result can be achieved. Tighten bolt h with f-th nut torque,
I can do two things.
従来は、ねＩＺを締め過ぎることを防止するため、慣性
モーメントの小さいモータを使い、着座までは締め過ぎ
ない範囲に押さえる必要がありだ。！−７かるに、本実
施例によれば常に抗力トルクを正嬉に把梶しながらねじ
締めを行うので、憤性モ・・−メンＩ・を大きく、モー
タの回転角速度を大きくしても適格なねじ締めを行うこ
辷が可能である．このことにより次のような多《の利点
がある。Conventionally, in order to prevent the bolt IZ from being over-tightened, it was necessary to use a motor with a small moment of inertia and to keep it within a range until the seat is seated. ! -7 However, according to this embodiment, since screw tightening is always carried out while carefully controlling the drag torque, it is possible to tighten the screws even if the resistance torque is increased and the rotational angular velocity of the motor is increased. It is possible to tighten screws. This has many advantages as follows.
＝一般に慣性モーメン１へが小さくモータトルクの大き
なモータは高価であるのに対し、慣性モーメントの大き
なモータは安価であるので、本実施例によれば慣性モー
メントの大きい安価なモータを用いることが可能となる
．
また、従来は慣性モーメントの影響をできるだけ押さえ
るようにしてねじ締めをしていたのに対し、本実施例で
は逆に慣性モーメントの力を利用してねじ締めを行って
おり、省エネルギーで効率的なねじ締めが行える．
また、大きな慣性モーメントのモータを用いることによ
り、ねじの抗力トルクが設定値に達するまえに自然に停
止して、所望のトルクでねじ締めすることができないと
いう事態を回避することができる．
さらに、本実施例によればねじ締めの初期の段階から高
速でねじ締めを行うことができる．通常、ねじ締め作業
は着座してからの締める角度よりも、着座までねじを回
転させる角度の方が圧倒的に大きい．しかも、着座する
までのモータ駆動は締め付けトルクに全く影響しない．
したがって、ねじ締め作業のトータルな時間短縮のため
には、着座してからのねじ締め時間より着座するまでの
時間を短くする方が有効である．しかし、従来はねじの
締め過ぎ防止のため＠座までの期間、高速回転できなか
った．しかるに、本実施例によれば、ねじの締め過ぎを
考慮することなく最初から高速でねじ締めを行うことが
できるので、ねじ締め作業全体の時間を大幅に短縮する
ことができる．本実施例によれば従来より３〜５倍以上
の角速度でねじ締めを行うことができ、ねじ締め時間を
３〜５分の１以上に短縮することができた．本発明は上
記実施例に限らず種々の変形が可能である．
上記実施例では抗力トルクが設定値に達するまでモータ
電流を一定値にしたが、モータの駆動開始時は大きな電
流を流してできるだけ速く起動させるようにし、一定速
度になった後は電流値を小さくするようにしてもよい．
また、本発明によれば抗力トルクｆ（θ）をモ二夕する
ことによってねじの［Ｊｕを確実に検出できる．よって
着座した後にモータの電流を切ってｇ（ｉ）一〇とし、
設定トルクまで慣性力のみでねじ締めを行い、設定トル
ク値に達した時点でブレーキ手段によって停止するよう
にしてもよい．また、ねじが着座した後、抗力トルクｆ
（θ〉が設定トルク値に達する以前にモータを停止する
か、回転角速度を減速する制御を行い、その後、慣性に
よる締め過ぎが発生しないような回転角速度で−Ｉ−ｄ
２θ／ｄｔ”与０の状態を維持したまま、モータの発生
トルクｇ（ｉ）によりねじ締めを進行し、抗力トルクｆ
（θ）が設定トルク値に達した時点でモータを停止する
ことによってねじ締めを行ってもよい．
さらに、モータ電流値は一定値でなくとも、モータトル
クｇ（ｉ）は検出できるので、例えば定速回転制御のよ
うな複雑なモータ制御を行ってもよい．また、抗力トル
クの設定値を段階的に複数用意して比較し、各段階でモ
ータ制御を変え、最後に締めつけるべきトルクで停止す
るようにしてもよい．
また、上記実施例では、ねじの抗力トルクｆ（θ）が目
標トルク値に達する直前にモータに逆方向の電流を流す
ことによりブレーキをかけたが、モータに機械的ブレー
キを設け、この機械的ブレーキを制御してモータにブレ
ーキをかけるようにしてもよい．また、例えば、モータ
の回転軸とビットとの間にクラッチを設け、ブレーキを
かける代わりにビットをモータから切り離してモータの
回転力が伝わらないようにしてもよい。ビットの慣性モ
ーメントはモータに比べて小さいのでモータから切り離
されると、ブレーキをかけた場合と同様に直ちに停止す
る．
また、基準となる抗力トルクのカーブと発生している抗
力トルクｆ（θ）とを比較し、連続的にモータな流を制
御して最終的に目標１・ルク値になった所で停止するよ
うにしてもよい．
また、上記実施例ではモータの回転角をエンコーダによ
り検出したが、他の手段により検出してもよい．また、
タコメータなどを用いて直接回転角速度を検出し、それ
を微分して回転角加速度を求めてもよい。さらに、モー
クから消接回転角加速度を挽出するようにしてもよい．
また、上記実施例では制御のための演算をアナログ回路
を用いて行っているが、マイク冑コンピュータ等を用い
たデジタル回路によって同様の演算を行ってもよい．
さらに、上記実施例では直流モータを用いたが、交流モ
ータ等の池の稚類のモータを用いてもよい。=In general, a motor with a small moment of inertia 1 and a large motor torque is expensive, whereas a motor with a large moment of inertia is inexpensive, so according to this example, an inexpensive motor with a large moment of inertia can be used. becomes. In addition, whereas conventionally screws were tightened by suppressing the influence of the moment of inertia as much as possible, in this example, the force of the moment of inertia is used to tighten the screws, which is energy-saving and efficient. Can be used to tighten screws. Furthermore, by using a motor with a large moment of inertia, it is possible to avoid the situation where the screw's drag torque spontaneously stops before reaching the set value and the screw cannot be tightened with the desired torque. Furthermore, according to this embodiment, screw tightening can be performed at high speed from the initial stage of screw tightening. Normally, when tightening a screw, the angle of rotation of the screw until it is seated is overwhelmingly larger than the angle of tightening after it is seated. Moreover, the motor drive until the seat is seated has no effect on the tightening torque.
Therefore, in order to reduce the total time required for screw tightening work, it is more effective to shorten the time it takes to tighten the screws after the person is seated, rather than the time it takes to tighten the screws after the person is seated. However, in the past, high speed rotation was not possible during the period up to the @ seat to prevent over-tightening of the screws. However, according to this embodiment, since screw tightening can be performed at high speed from the beginning without considering over-tightening, the overall time for screw tightening work can be significantly shortened. According to this embodiment, screw tightening can be performed at an angular velocity 3 to 5 times higher than that of the conventional method, and the screw tightening time can be reduced to 3 to 5 times or more. The present invention is not limited to the above embodiments, and various modifications are possible. In the above example, the motor current was kept at a constant value until the drag torque reached the set value, but when the motor started driving, a large current was applied to start it as quickly as possible, and after the motor reached a constant speed, the current value was reduced. You may also do this. Further, according to the present invention, by monitoring the drag torque f(θ), it is possible to reliably detect the [Ju] of the screw. Therefore, after sitting down, cut off the motor current and set g(i) to 10.
The screw may be tightened by inertia alone until the set torque is reached, and then stopped by braking means when the set torque is reached. Also, after the screw is seated, the drag torque f
(The motor is stopped or the rotational angular velocity is controlled to be decelerated before θ〉 reaches the set torque value, and then the rotational angular velocity is set to -I-d to prevent over-tightening due to inertia
2θ/dt" while maintaining the state of 0, screw tightening is proceeded by the torque g(i) generated by the motor, and the drag torque f
The screw may be tightened by stopping the motor when (θ) reaches the set torque value. Furthermore, since the motor torque g(i) can be detected even if the motor current value is not a constant value, complex motor control such as constant speed rotation control may be performed. It is also possible to prepare and compare multiple setting values for the drag torque in stages, change the motor control at each stage, and finally stop at the torque that should be tightened. Furthermore, in the above embodiment, the brake is applied by applying a current in the opposite direction to the motor just before the drag torque f(θ) of the screw reaches the target torque value. It is also possible to apply the brake to the motor by controlling the brake. Further, for example, a clutch may be provided between the rotating shaft of the motor and the bit, and instead of applying the brake, the bit may be separated from the motor to prevent the rotational force of the motor from being transmitted. The moment of inertia of the bit is smaller than that of the motor, so if it is disconnected from the motor, it will stop immediately, just like applying a brake. In addition, the reference drag torque curve and the generated drag torque f(θ) are compared, and the motor flow is continuously controlled until it finally stops when the target value of 1·L is reached. You can do it like this. Further, in the above embodiment, the rotation angle of the motor is detected by the encoder, but it may be detected by other means. Also,
The rotational angular velocity may be directly detected using a tachometer or the like, and the rotational angular acceleration may be determined by differentiating it. Furthermore, the tangent rotational angular acceleration may be extracted from the mork. Further, in the above embodiment, the calculation for control is performed using an analog circuit, but the same calculation may be performed using a digital circuit using a microphone computer or the like. Furthermore, although a direct current motor is used in the above embodiment, a similar motor such as an alternating current motor may also be used.
［発明の効果］
以Ｌの通り、本発明によ紅ば、常に適切な締め付Ｃフカ
で高速でね（二締めを行うことができる．[Effects of the Invention] As described below, according to the present invention, it is possible to always perform two tightenings at high speed with an appropriate tightening force.
第１図は本発明の原理説明図、
第２図は本発明の一実施例によるねじ締め装置のブロッ
ク図、
第３図は同ねじ締め装置の動作を示すタイムチャートで
ある．
図において、
】・・・ねじ
２・・・モータ
３・・・ビット
４・・・回転角加速度検出手段
５・・・トルク検出手段
６・・・モータ駆動制御千段
１０・・・ねじ
１０ａ・・・ねじ頭
１２・・・モータ
１４・・・ビット
１６・・・エンコーダ
１８、２０・・・微分回路
２２、２４・・・乗算部
２６・・・減算部
２８・・・比較部
２９・・・トルク設定部
３０・・・モータ電流切換スイッチ
３２・・・モータ駆勤部
３４・・・定速回転制御部
第１図
本失明の一冥距！’１１こよるねじ締わ質夏の勧作乞示
寸タイムテ▼一ト第３図Fig. 1 is a diagram explaining the principle of the present invention, Fig. 2 is a block diagram of a screw tightening device according to an embodiment of the present invention, and Fig. 3 is a time chart showing the operation of the same screw tightening device. In the figure, ]...Screw 2...Motor 3...Bit 4...Rotational angular acceleration detection means 5...Torque detection means 6...Motor drive control stage 10...Screw 10a... ...Screw head 12...Motor 14...Bit 16...Encoder 18, 20...Differentiating circuit 22, 24...Multiplication section 26...Subtraction section 28...Comparison section 29...・Torque setting section 30...Motor current changeover switch 32...Motor driving section 34...Constant speed rotation control section Fig. 1 A journey to blindness! '11 High quality summer solicitation timetable ▼ Figure 3
Claims (1)
めるねじ締め方法において、 慣性モーメントをＩ、前記モータの回転角をθ、前記モ
ータの電流値をｉとして、前記モータの発生するモータ
トルクｇ（ｉ）及び前記モータの回転角加速度ｄ＾２θ
／ｄｔ＾２を検出しながら、運動方程式 ｆ（θ）＝−Ｉ・ｄ＾２θ／ｄｔ＾２＋ｇ（ｉ）に基づ
いてねじの抗力トルクｆ（θ）を演算し、前記モータ停
止時の前記抗力トルクｆ（θ）が予め設定された目標ト
ルク値になるように前記モータを駆動制御することを特
徴とするねじ締め方法。 ２、請求項１記載のねじ締め方法において、ねじの抗力
トルクｆ（θ）が前記目標トルク値に達する直前に前記
モータにブレーキをかけて、前記モータの停止時に前記
ねじの抗力トルクが前記目標トルク値になるように前記
ねじを締めることを特徴とするねじ締め方法。 ３、モータによりねじを回転させることによりねじを締
めるねじ締め装置において、 前記モータの回転角加速度ｄ＾２θ／ｄｔ＾２を検出す
る回転角加速度検出手段と、 前記モータの電流値をｉとして、前記モータの発生する
モータトルクｇ（ｉ）を検出するトルク検出手段と、 前記回転角加速度検出手段からの回転角加速度ｄ＾２θ
／ｄｔ＾２及び前記トルク検出手段からのモータトルク
ｇ（ｉ）から、運動方程式 ｆ（θ）＝−Ｉ・ｄ＾２θ／ｄｔ＾２＋ｇ（ｉ）に基づ
いてねじの抗力トルクｆ（θ）を演算し、前記モータ停
止時の前記抗力トルクｆ（θ）が予め設定された目標ト
ルク値になるように前記モータを駆動制御するモータ駆
動制御手段と を備えたことを特徴とするねじ締め装置。 ４、請求項３記載のねじ締め装置において、前記モータ
にブレーキをかけるブレーキ手段を備え、 ねじの抗力トルクｆ（θ）が前記目標トルク値に達する
直前に前記ブレーキ手段により前記モータにブレーキを
かけて、前記モータの停止時に前記ねじの抗力トルクｆ
（θ）が前記目標トルク値になるように前記ねじを締め
ることを特徴とするねじ締め装置。[Claims] 1. In a screw tightening method of tightening a screw by rotating the screw with a motor, where the moment of inertia is I, the rotation angle of the motor is θ, and the current value of the motor is i, the generation of the motor is The motor torque g(i) and the rotational angular acceleration d^2θ of the motor
While detecting A screw tightening method characterized in that the motor is drive-controlled so that the drag torque f(θ) becomes a preset target torque value. 2. In the screw tightening method according to claim 1, a brake is applied to the motor immediately before the resistance torque f(θ) of the screw reaches the target torque value, and when the motor stops, the resistance torque of the screw reaches the target torque value. A screw tightening method characterized by tightening the screw to a torque value. 3. A screw tightening device that tightens a screw by rotating the screw with a motor, comprising: rotational angular acceleration detection means for detecting rotational angular acceleration d^2θ/dt^2 of the motor; and a current value of the motor as i; Torque detection means for detecting motor torque g(i) generated by the motor; and rotational angular acceleration d^2θ from the rotational angular acceleration detection means.
/dt^2 and the motor torque g(i) from the torque detection means, the drag torque f(θ) of the screw is determined based on the equation of motion f(θ)=-I・d^2θ/dt^2+g(i). and a motor drive control means for controlling the motor so that the drag torque f(θ) when the motor is stopped becomes a preset target torque value. . 4. The screw tightening device according to claim 3, further comprising a brake means for applying a brake to the motor, and the brake means applies a brake to the motor immediately before the resistance torque f(θ) of the screw reaches the target torque value. Then, when the motor is stopped, the resistance torque f of the screw is
A screw tightening device characterized in that the screw is tightened so that (θ) becomes the target torque value.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP1163080A JP2646445B2 (en) | 1989-06-26 | 1989-06-26 | Screw fastening method and device |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP1163080A JP2646445B2 (en) | 1989-06-26 | 1989-06-26 | Screw fastening method and device |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPH0326431A true JPH0326431A (en) | 1991-02-05 |
| JP2646445B2 JP2646445B2 (en) | 1997-08-27 |
Family
ID=15766806
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP1163080A Expired - Lifetime JP2646445B2 (en) | 1989-06-26 | 1989-06-26 | Screw fastening method and device |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JP2646445B2 (en) |
Cited By (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| WO2006048420A1 (en) * | 2004-11-04 | 2006-05-11 | Paul-Heinz Wagner | Method for controlling a tightness property of a screw device |
| FR2972665A1 (en) * | 2011-03-18 | 2012-09-21 | Renault Georges Ets | Method for automatically adjusting speed of electric screwdriver during cycle of tightening screw, involves activating braking unit at determined braking start time, so that torque value is within theoretical range of tolerance |
| WO2018230140A1 (en) * | 2017-06-16 | 2018-12-20 | パナソニックＩｐマネジメント株式会社 | Power tool |
| WO2023162439A1 (en) * | 2022-02-25 | 2023-08-31 | パナソニックホールディングス株式会社 | Electric tool |
Citations (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS63212425A (en) * | 1987-02-23 | 1988-09-05 | Nitto Seiko Co Ltd | Poor tightening detecting device for automatic screw tightening machine |
-
1989
- 1989-06-26 JP JP1163080A patent/JP2646445B2/en not_active Expired - Lifetime
Patent Citations (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS63212425A (en) * | 1987-02-23 | 1988-09-05 | Nitto Seiko Co Ltd | Poor tightening detecting device for automatic screw tightening machine |
Cited By (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| WO2006048420A1 (en) * | 2004-11-04 | 2006-05-11 | Paul-Heinz Wagner | Method for controlling a tightness property of a screw device |
| FR2972665A1 (en) * | 2011-03-18 | 2012-09-21 | Renault Georges Ets | Method for automatically adjusting speed of electric screwdriver during cycle of tightening screw, involves activating braking unit at determined braking start time, so that torque value is within theoretical range of tolerance |
| WO2018230140A1 (en) * | 2017-06-16 | 2018-12-20 | パナソニックＩｐマネジメント株式会社 | Power tool |
| US11396092B2 (en) | 2017-06-16 | 2022-07-26 | Panasonic Intellectual Property Management Co., Ltd. | Electric power tool provided with motor controller controlling motor including limiter for limitting current contributing to torque generation |
| WO2023162439A1 (en) * | 2022-02-25 | 2023-08-31 | パナソニックホールディングス株式会社 | Electric tool |
Also Published As
| Publication number | Publication date |
|---|---|
| JP2646445B2 (en) | 1997-08-27 |
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