SCREW FASTENING TORQUE DETECTION METHOD AND DEVICE OF CONSTANT TORQUE ELECTRIC SCREWDRIVER

• Main Author: TOTSU KATSUYUKI
• Format: Patent
• Language: English; Japanese
• Published: 25.05.2017
• Subjects: HAND TOOLS; MANIPULATORS; MEASURING; MEASURING FORCE, STRESS, TORQUE, WORK, MECHANICAL POWER,MECHANICAL EFFICIENCY, OR FLUID PRESSURE; PERFORMING OPERATIONS; PHYSICS; PORTABLE POWER-DRIVEN TOOLS; TESTING; TOOLS OR BENCH DEVICES NOT OTHERWISE PROVIDED FOR, FORFASTENING, CONNECTING, DISENGAGING OR HOLDING; TRANSPORTING

PROBLEM TO BE SOLVED: To provide a screw fastening torque detection method and device of a constant torque electric screwdriver using a torque limiter, which can properly detect screw fastening torque in screw fastening work, and can easily and surely attain quality determination of a screw fastening state.SOLUTION: A screw fastening torque detection method of a constant torque electric screwdriver is configured such that with seating of a screw in screw fastening operation, screw fastening torque from a screwdriver bit 20 exceeds setting torque of a torque limiter 18, and then a driving rotation part of the torque limiter starts idling; and at the same time, an internal gear of a planar gear reduction mechanism 16 connected to a driving shaft of an electric motor 12 generates abrupt rotational force in a direction reverse to rotation of an output shaft of the internal gear, the rotational force as stress displacement is transmitted to a torsion bar, and the stress displacement of the torsion bar is detected as screw fastening torque by a distortion gauge 28.SELECTED DRAWING: Figure 1 【課題】トルクリミッタを使用する定トルク電動ドライバーにおいて、ねじ締め作業における適正なねじ締めトルクの検出を行うことができると共に、ねじ締め状態の良否判定も容易かつ確実に達成することができる定トルク電動ドライバーのねじ締めトルク検出方法および装置を提供する。【解決手段】ねじ締め操作におけるねじの着座に伴い、ドライバービット２０によるねじ締めトルクがトルクリミッタ１８の設定トルクを超えて、トルクリミッタの駆動回転部が空転を開始すると同時に、電動モータ１２の駆動軸に結合された遊星歯車減速機構１６のインターナルギヤがその出力軸の回転に対し反転する方向に発生する急激な回動力を応力変位としてトーションバーに伝達し、このトーションバーの応力変位をひずみゲージ２８によりねじ締めトルクとして検出する構成からなる。【選択図】図１