Patent ID: 9701000
Date: 2017-07-11
CPC Classifications: B25B

Claim:
1. An impact rotation tool comprising: a drive source; an impact force generation unit configured to generate an impact force for converting power from the drive source to pulsed torque; a shaft arranged to transmit the pulsed torque to a bit used to perform a tightening task; a torque measurement unit configured to measure torque applied to the shaft as measured torque; a rotation angle measurement unit configured to measure a rotation angle of the shaft; a tightening torque calculation unit configured to calculate an angular acceleration from the rotation angle and calculate a tightening torque based on the angular acceleration and the measured torque; and a controller configured to control the drive source based on the tightening torque, wherein when T represents the tightening torque, Ts represents the measured torque, I represents a moment of inertia of the shaft, and α represents the angular acceleration, the tightening torque calculation unit is configured to calculate the tightening torque from the equation of T=Ts×A−I×α×B+C, where A, B, and C are correction coefficients.