Portable electric tool

Abstract

A portable electric tool includes an output shaft extending in an axial direction and configured to be rotatable, a tool accessory configured to perform an eccentric circular motion according to the rotation of the output shaft, a dust collection fan fixed to the output shaft so as to circumferentially surround the output shaft, a motor disposed on an opposite side of the dust collection fan from the tool accessory in the axial direction and configured to provide a rotational driving force to the output shaft, a motor cooling fan disposed between the dust collection fan and the motor in the axial direction, a first weight attached to one of the dust collection fan and the motor cooling fan and having a specific gravity higher than the one of the fans, and a second weight disposed at a position different from the first weight in the axial direction.

What is claimed is: 
     
         1 . A portable electric tool comprising:
 an output shaft extending in an axial direction and configured to be rotatable;   a tool accessory configured to perform an eccentric circular motion according to the rotation of the output shaft;   a dust collection fan fixed to the output shaft so as to circumferentially surround the output shaft;   a motor disposed on an opposite side of the dust collection fan from the tool accessory in the axial direction, and configured to provide a rotational driving force to the output shaft;   a motor cooling fan disposed between the dust collection fan and the motor in the axial direction;   a first weight attached to one of the dust collection fan and the motor cooling fan and having a specific gravity higher than the one of the fans; and   a second weight disposed at a position different from the first weight in the axial direction.   
     
     
         2 . The portable electric tool according to  claim 1 , wherein the first weight and the second weight are disposed so as to be spaced apart from each other in the axial direction via a spacer. 
     
     
         3 . The portable electric tool according to  claim 1 , wherein the dust collection fan and the motor cooling fan are disposed so as to be spaced apart from each other in the axial direction. 
     
     
         4 . The portable electric tool according to  claim 3 , wherein the first weight and the second weight are disposed so as to be spaced apart from each other in the axial direction via a spacer, and
 the dust collection fan and the motor cooling fan are disposed so as to be spaced apart from each other in the axial direction via the spacer.   
     
     
         5 . The portable electric tool according to  claim 1 , wherein the first weight is attached to the dust collection fan and has a specific gravity higher than the dust collection fan,
 the motor cooling fan is fixed to the output shaft so as to circumferentially surround the output shaft, and   the second weight is attached to the motor cooling fan and has a specific gravity higher than the motor cooling fan.   
     
     
         6 . The portable electric tool according to  claim 5 , wherein the dust collection fan is made from light metal, and
 the first weight is made from heavy metal.   
     
     
         7 . The portable electric tool according to  claim 6 , wherein the first weight is attached to the dust collection fan by screwing. 
     
     
         8 . The portable electric tool according to  claim 5 , wherein the motor cooling fan is made from synthetic resin, and
 the second weight is made from metal.   
     
     
         9 . The portable electric tool according to  claim 5 , wherein the second weight includes a through-hole through which the output shaft extends. 
     
     
         10 . The portable electric tool according to  claim 1 , wherein the first weight includes a through-hole through which the output shaft extends. 
     
     
         11 . The portable electric tool according to  claim 2 , wherein the spacer is in the form of a first bearing rotatably supporting the output shaft. 
     
     
         12 . The portable electric tool according to  claim 1 , wherein the dust collection fan, the motor cooling fan, the first weight, and the second weight are fixed to the motor shaft by fastening them together. 
     
     
         13 . The portable electric tool according to  claim 1 , wherein the dust collection fan includes a shaft portion extending in the axial direction toward an opposite side from the output shaft, the shaft portion being eccentric with respect to the output shaft, and
 the tool accessory is fixed to the shaft portion via a second bearing rotatably supporting the shaft portion.   
     
     
         14 . The portable electric tool according to  claim 2 , wherein the dust collection fan and the motor cooling fan are disposed so as to be spaced apart from each other in the axial direction,
 the dust collection fan and the motor cooling fan are disposed so as to be spaced apart from each other in the axial direction via the spacer,   the first weight is attached to the dust collection fan and has a specific gravity higher than the dust collection fan,   the motor cooling fan is fixed to the output shaft so as to circumferentially surround the output shaft, and   the second weight is attached to the motor cooling fan and has a specific gravity higher than the motor cooling fan.   
     
     
         15 . The portable electric tool according to  claim 5 , wherein the second weight includes a through-hole through which the output shaft extends, and
 the first weight includes a through-hole through which the output shaft extends.   
     
     
         16 . The portable electric tool according to  claim 14 , wherein the spacer is in the form of a first bearing rotatably supporting the output shaft. 
     
     
         17 . The portable electric tool according to  claim 16 , wherein the dust collection fan, the motor cooling fan, the first weight, and the second weight are fixed to the motor shaft by fastening them together. 
     
     
         18 . The portable electric tool according to  claim 16 , wherein the dust collection fan includes a shaft portion extending in the axial direction toward an opposite side from the output shaft, the shaft portion being eccentric with respect to the output shaft, and
 the tool accessory is fixed to the shaft portion via a second bearing rotatably supporting the shaft portion.