TORQUE SENSING UNIT FOR A POWER TOOL AND A POWER TOOL COMPRISING SUCH A TORQUE SENSING UNIT

摘要

A torque sensing unit for a power tool arranged to generate a torque responsive signal by sensing the reaction torque transferred from a ring gear of a planetary reduction gearing (12) to the tool housing (10), wherein the torque sensing unit (20) comprises an annular torque transferring element (22) disposed perpendicularly to the geometric axis of the ring gear (16) and being formed with a first pair of external engagement portions (24,25) for connecting the torque transferring element (22) to the housing (10), and a second pair of external engagement portions (27,28) for connecting the torque transferring element (22) to the ring gear (16), and at least one pair of weak elastically deformable zones (42a-d) located between the engagement portions (24,25,27,28) and provided with sensors (43) for delivering signals in response to the transferred reaction torque.