| 摘要 |
<P>PROBLEM TO BE SOLVED: To provide a rechargeable power tool in which rotation of a DC motor is PWM-controlled according to a set speed, wherein the rechargeable power tool can positively detect an abnormal state of the tool irrespective of the set speed. Ž<P>SOLUTION: According to the operation of the rechargeable power tool, a DUTY of the DC motor is set according to a speed mode (any of a high speed, an intermediate speed, and a low speed) set by the user, and a pulling amount of a trigger switch (S140), and a voltage detecting threshold value Vt and a lock determining time Tr for detecting the abnormal state of the tool are set according to the DUTY (S150). Specifically the voltage detecting threshold value Vt is set to a lower value and the lock determining time Tr is set to a shorter value as the DUTY is larger. After starting of energization of the DC motor according to the DUTY (S160), if the lock determining time Tr has elapsed without updating a hall signal (S190:YES) or a battery voltage Vb falls below the voltage detecting threshold value Vt (S220:YES), it is determined that the tool is in the abnormal state, and energization of the DC motor is stopped (S230, S250). Ž<P>COPYRIGHT: (C)2010,JPO&INPIT Ž
|
