| 摘要 |
<p>An electric screwdriver includes a housing, a motor having a rotor and a maximum torque at constant speed of Cmax, and an end member. A transmission drives the end member and has a reduction gear coupled to the motor and having a ratio R and an efficiencyμ. A torque sensor detects an attainment of a set value torque Cc. A motor driver drives the motor with a series of electric current impulses, The transmission enables an accumulation of kinetic energy Ec in the rotor and a restitution to the end member of the kinetic energy Ec between two impulses from the motor driver. The motor and reduction gear are configured such that: R*μ*Cmax<Cc, the set value of torque Cc being attained through the transfer of kinetic energy Ec to the end member, wherein ratio R is smaller than or equal to 10/(μCmax).</p> |
