| 摘要 |
PROBLEM TO BE SOLVED: To provide an impact tool capable of surely stopping rotation of a motor at a seating time point. SOLUTION: This impact tool is provided with a fastening deciding part 21 for deciding seating based on fastening torque T estimated by a torque estimating part 14 to stop the motor 1. The fastening deciding part 21 calculates amount of torque variationΔT to be a variation ratio of the fastening torque T and a coefficient of torque variationΔΔT to be a variation ratio of the amount of torque variationΔT and decides the seating when the coefficient of torque variationΔΔT is changed from positive to negative and the fastening torque T exceeds prescribed lower limit torque T1 after an integrated value or an integration value of the coefficient of torque variationΔΔT in a section where the coefficient of torque variationΔΔT continuously becomes positive exceeds a prescribed threshold value C. The impact tool is provided with a torque setting switch 23 for allowing a worker to freely set the lower limit torque T1. COPYRIGHT: (C)2007,JPO&INPIT
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