Impact tool and method of controlling impact tool

A method of controlling an impact tool including a motor, a trigger, a semiconductor switch element which controls driving power supplied to the motor and a striking mechanism configured to drive a tip tool by rotation force of the motor, the striking mechanism including a hammer and an anvil, the method comprising:

• driving the semiconductor switch element to drive the motor when the trigger is manipulated;
• at a first period that a portion of the hammer engages with a portion of the anvil to rotate the anvil, driving the semiconductor switch element at a high duty ratio;
• and
• at a second period, which is after the first period, that the hammer and the anvil repeat a striking since the portion of the hammer is disengaged from the portion of the anvil, driving the semiconductor switch element at low duty ratio which is lower than the high duty ratio, and
• changing a duty ratio for a control of the semiconductor switching element from the high duty ratio to the low duty ratio prior to shifting to the second period, and maintaining the low duty ratio to be lower than the high duty ratio during the second period and while a plurality of strikes are implemented.

An impact tool comprising:

• a motor;
• a trigger;
• a controller configured to control driving power supplied to the motor using a semiconductor switching element according to an operation of the trigger;
• a striking mechanism configured to drive a tip tool by rotation force of the motor, the striking mechanism including a hammer and an anvil;
• and
• a current detector configured to detect a current value of current flowing in the motor or the semiconductor switching element,
• wherein at a first period in which a portion of the hammer engages with a portion of the anvil to rotate the anvil, the controller controls the semiconductor switching element at a high duty ratio,
• wherein at a second period, which is after the first period, in which the hammer and the anvil repeat a striking since the portion of the hammer is disengaged from the portion of the anvil, the controller controls the semiconductor switching element at a low duty ratio lower than the high duty ratio, and
• wherein the controller is configured to change a duty ratio for control of the semiconductor switching element from the high duty ratio to the low duty ratio based on a detection result of the current detector and to maintain the low duty ratio to be lower than the high duty ratio during the second period and while a plurality of strikes are implemented.

An impact tool comprising:

• a motor;
• a trigger;
• a controller configured to control driving power supplied to the motor using a semiconductor switching element according to an operation of the trigger;
• a striking mechanism configured to drive a tip tool by rotation force of the motor, the striking mechanism including a hammer and an anvil, and
• wherein at a first period in which a portion of the hammer engages with a portion of the anvil to rotate the anvil, the controller controls the semiconductor switching element at a high duty ratio,
• wherein at a second period, which is after the first period, in which the hammer and the anvil repeat a striking since a first striking of the hammer on the anvil, the controller controls the semiconductor switching element at a low duty ratio lower than the high duty ratio, and
• wherein at a third period between the first period and the second period, the controller controls the semiconductor switching element at a low duty ratio lower than the high duty ratio.

A method of controlling an impact tool including a motor, a trigger, a semiconductor switch element which controls driving power supplied to the motor and a striking mechanism configured to drive a tip tool by rotation force of the motor, the striking mechanism including a hammer and an anvil, the method comprising:

• driving the semiconductor switch element to drive the motor when the trigger is manipulated;
• at a first period in which a portion of the hammer engages with a portion of the anvil to rotate the anvil, driving the semiconductor switch element at a high duty ratio;
• at a second period, which is after the first period, in which the hammer and the anvil repeat a striking since a first striking of the hammer on the anvil, driving the semiconductor switch element at a low duty ratio which is lower than the high duty ratio;
• and
• at a third period between the first period and the second period, driving the semiconductor switch element at a low duty ratio which is lower than the high duty ratio.