Electric tool

Abstract

To provide a cordless electric tool promoting a fastening function or a cutting function by facilitating to control a rotational number of a motor from a low speed region to a high speed region, reducing generation of vibration or noise and achieving small-sized formation and light-weighted formation, there is provided a cordless electric tool constituted by a brushless direct current motor 3 , an output shaft 5 connected to the brushless direct current motor 3 via a speed changing device 4 , a motor driving circuit 7 and a control portion 8 of the driving circuit and using a charge type battery 11 as a drive power source.

What is claimed is:  
     
         1 . An electric tool which is a cordless electric tool comprising a motor, an output shaft connected to the motor via a speed changing device, a motor driving circuit and a control portion of the driving circuit and using a charge type battery as a drive power source: 
 wherein the motor is a brushless direct current motor.    
     
     
         2 . An electric tool comprising: 
 a brushless direct current motor constituting a power source of the electric tool;    a first operating member for changing a maximal rotational speed of the brushless direct current motor;    a second operating member for changing a rotational speed of the brushless direct current motor within a range of the maximal rotational speed of the brushless direct current motor set by the first operating member; and    controlling means for controlling a rotational state of the brushless direct current motor;    wherein the controlling means comprises: 
 maximal rotational speed signal outputting means for outputting a maximal rotational speed signal in correspondence with a displacement of the first operating member; and  
 rotational speed signal outputting means for constituting a maximal level by the maximal rotational speed signal outputted from the maximal rotational speed signal outputting means and outputting a rotational speed signal in correspondence with a displacement of the second operating means to thereby drive to rotate the brushless direct current motor.  
   
     
     
         3 . The electric tool according to  claim 1  or  2 : 
 wherein the electric tool is an electric driver, an electric driver drill, an electric impact driver or an electric wrench.