Power tool with motor having a multi-piece stator

Abstract

A power tool is provided including a housing and an electric motor disposed in the housing. The motor includes a stator having pole pieces mated together and field coils disposed on the pole pieces, the stator having an outside diameter. The motor also includes an armature having an outside diameter that is at least 0.625 of the outside diameter of the stator.

What is claimed is: 
     
         1 . An electric motor, comprising:
 a stator having pole pieces mated together and field coils disposed on the pole pieces, the stator having an outside diameter; and   an armature having an outside diameter that is at least 0.625 of the outside diameter of the stator.   
     
     
         2 . The motor of  claim 1  wherein the field coils extend beyond pole tips of the pole pieces on which they are disposed. 
     
     
         3 . The motor of  claim 1  including insulating sleeves in which the field coils are received, the insulating sleeves disposed between the field coils and surfaces of the pole pieces. 
     
     
         4 . The motor of  claim 1  wherein the pole pieces have mating features. 
     
     
         5 . The motor of  claim 1  wherein lengths of coil ends of each field coil are insulated with one of TFE and PTFE tubing to provide lead wires for each field coil. 
     
     
         6 . The motor of  claim 1  wherein the motor is thermally balanced. 
     
     
         7 . An electric motor, comprising:
 a stator having pole pieces mated together and field coils disposed on the pole pieces, the field coils extending beyond pole tips of the pole pieces on which they are disposed, the stator having an outside diameter; and   an armature having an outside diameter that is at least 0.625 of the outside diameter of the stator.   
     
     
         8 . The motor of  claim 7  wherein the field coils have an included angle of at least 110% of an included angle of the pole tips. 
     
     
         9 . The motor of  claim 7  wherein the field coils have a packing factor of at least 60%. 
     
     
         10 . The motor of  claim 7  including insulating sleeves in which the field coils are received, the insulating sleeves disposed between the field coils and surfaces of the pole pieces. 
     
     
         11 . The motor of  claim 7  wherein the pole pieces have mating features. 
     
     
         12 . A hand-held power tool, comprising:
 a housing;   a motor disposed in the housing, the motor including: a stator having pole pieces mated together and field coils disposed on the pole pieces, the field coils extending beyond pole tips of the pole pieces on which they are disposed, the stator having an outside diameter; and an armature having an outside diameter that is at least 0.625 of the outside diameter of the stator.   
     
     
         13 . The power tool of  claim 12  wherein the field coils have an included angle of at least 110% of an included angle of the pole tips. 
     
     
         14 . The power tool of  claim 12  wherein the field coils have a packing factor of at least 60%. 
     
     
         15 . The power tool of  claim 12 , wherein the stator includes insulating sleeves in which the field coils are received, the insulating sleeves disposed between the field coils and surfaces of the pole pieces. 
     
     
         16 . The power tool of  claim 12 , wherein the pole pieces have mating features. 
     
     
         17 . The apparatus of  claim 12 , wherein the power tool is a small angle grinder.