Power tool

Abstract

Blades are provided on a fan body such that an outer diameter d 2 of the fan body is in a range of 45 mm≦d 2 ≦50 mm, an axial height h 1 at a substantially intermediate position of the blade is in a range of 0.2≦h 1 /d 2 ≦0.3 with respect to the outer diameter of the fan body, and an axial height h 2 at an outer peripheral edge of the blade is in a range of 0.12≦h 2 /d 2 ≦0.17 with respect to the outer diameter d 2 of the fan body.

1 . A power tool comprising: 
 a housing in which an inlet port for introducing air and an outlet port for exhausting the air are formed;    a motor having a rotor and a stator, which is accommodated in the housing; and    a centrifugal fan capable of rotating with the rotor, which is fixed coaxially to the rotor, the centrifugal fan including; 
 a disc-shaped fan body; and  
 a plurality of blades capable of flowing the air along an axial direction of the rotor radially and outwardly of the fan body, the blades extending from a predetermined position in a radial direction of the fan body to an outer peripheral edge of the fan body, and the blades formed at predetermined pitches along a circumferential direction of the fan body;  
   a first channel formed between the stator and the housing; and    a second channel formed between the stator and the rotor, wherein    a value S 0  is defined by a sectional area which is smallest in the first channel and the second channel among cross sections which are perpendicular to an axial direction of the rotor and are arranged in an axial direction of the rotor,    the value S 0  is in a range of 350 mm 2 ≦S 0 ≦650 mm 2 ,    an outer diameter d 2  of the fan body is in a range of 45 mm≦d 2 ≦50 mm , and a height h 1  in the axial direction of the blade at a position where the blade is highest with respect to the outer diameter of the fan body is in a range of 0.2≦h 1 /d 2 ≦0.3.    
   
   
       2 . The power tool according to  claim 1 , wherein 
 the height h 1  in the axial direction of the blade at the position where the blade is highest is in a range of 0.25≦h 1 /d 2 ≦0.3 with respect to the outer diameter d 2  of the fan body.    
   
   
       3 . The power tool according to  claim 2 , wherein 
 a height h 2  in the axial direction of the blade at an outer peripheral edge of the blade is in a range of 0.12≦h 2 /d 2 ≦0.17 with respect to the outer diameter d 2  of the fan body.    
   
   
       4 . The power tool according to  claim 1 , wherein 
 a number of the blades, n, is in a range of 23≦n≦30.    
   
   
       5 . The power tool according to  claim 4 , wherein the number of the blades, n, is in a range of 25≦n≦28.  
   
   
       6 . The power tool according to  claim 1 , wherein 
 a first area S 1  is defined by product of both a distance L 1  and a height h 1 , where the distance L 1  is defined along a circumferential direction of the fan body and between opposing portions of mutually adjacent blades where the blades are highest, and the height h 1  of the blades is defined in an axial direction of the blades where the blades are highest,    an inside diameter d 1  is defined by a distance between a pair of the blades located in a same diametrical direction of the fan body where the pair of blades are highest, and    a second area S 2  is defined by a product of a distance L 2  and a height h 2 , where the distance L 2  is defined along a circumferential direction of the fan body and between opposing portions of the mutually adjacent blades at outer peripheral edges thereof, and the height h 2  is defined in an axial direction of the blade at the outer peripheral edge thereof,    d 2  is defined by an outer diameter of the fan body, and    S 1 , S 2 , d 1 , and d 2  are arranged to satisfy a relationship of S 1 ·d 1 =(1±0.3)S 2 ·d 2 .    
   
   
       7 . The power tool according to  claim 1 , wherein 
 the blades are configured by an inward portion extending from the predetermined radial position to the position where the blades are highest and an outward portion extending from the position where the blades are highest to the outer peripheral edge,    a direction extending toward the outward portion of the blades is inclined by a first predetermined angle α 1  in an opposite direction to a rotating direction of the fan with respect to a straight line connecting a center of the fan and an outer peripheral edge of the outward portion of the blades    a direction extending toward the inward portion of the blades is inclined by a second predetermined angle α 2  in the opposite direction to the rotating direction of the fan with respect to a straight line connecting the center of the fan and the predetermined radial position,    the first predetermined angle α 1  is in a range of 30°≦α 1 ≦50°, and    the second predetermined angle α 2  is in a range of 0°≦α 2 ≦10°.    
   
   
       8 . The power tool according to  claim 6 , wherein 
 the first predetermined angle α 1  is in a range of 35°≦α 1 ≦45°, and    the second predetermined angle α 2  is in a range of 2.5°≦α 2 ≦7.5°.