Hammer drill controls predetermined sizes of turn of hammer based on angle of rotation of hammer which is obtained according to rotational position output of rotor

摘要

The drill (1) has motor (3) with rotor (3a), stator (3b), and detection device which detects a rotational position of the rotor. A pressure pad is designed to turn in relation to hammer, while output shaft is connected to counter-holder. The turn of hammer in forward rotational direction about second predetermined size is performed by counter-holder, while turn of hammer is performed in reverse direction by first predetermined size. The predetermined sizes of turn of hammer are controlled based on angle of rotation of hammer obtained according to output of detection apparatus.