ELECTRONIC CLUTCH FOR POWER TOOL

摘要

A method is presented for controlling operation of a power tool having an electric motor drivably coupled to an output spindle. The method includes: receiving an input indicative of a clutch setting for an electronic clutch, where the clutch setting is selectable from a plurality of driver modes; setting the value of a maximum current threshold in accordance with the selected one of the plurality of driver modes; determining rotational speed of the electric motor; determining an amount of current being delivered to the electric motor; comparing the amount of current being delivered to the electric motor to the maximum current threshold; and interrupting transmission of torque to the output spindle when the amount of current being delivered to the electric motor exceeds the maximum current threshold and the rotational speed of the electric motor is decreasing.

主权项

1. A power tool comprising:
a housing; an output spindle; an electric motor disposed in the housing and configured to provide torque to the output spindle; an input switch for actuating the motor; an electronic clutch configured to interrupt transmission of torque to the output spindle when a threshold torque value is exceeded, the electronic clutch including
a current sensing circuit that generates a sensed current signal that corresponds to an amount of current being delivered to the motor;a rotation sensing circuit that generates a sensed rotation signal that corresponds to at least one of an angular position, a speed, and an acceleration of the motor output shaft; anda controller coupled to the current sensing circuit and the rotation sensing circuit, wherein the controller, in a first mode of operation, initiates a first protective operation to interrupt transmission of torque to the output spindle when the sensed rotation signal indicates that the rotational speed of the motor is decreasing and the sensed current signal exceeds a first current threshold value.