Patent ID: 6586855
Filing Date: 2003-07-01
Classification: H02K

Abstract:
A universal electric motor for driving an electrical hand-held tool device which experiences a high dust load, comprising a commutator (2) rotatable about an axis (A), said commutator comprises a rotor with lamellas located on said rotor, carbon brushes (9) arranged to be contacted by said lamellas, an axially extending peripherally closed protective shield (3) for protecting the rotor and carbon brushes against dust particles carried along in an air stream which ventilates and cools the rotor and carbon brushes, said protective shield (3) encloses said rotor and carbon brushes and has an inner casing surface radially spaced outwardly from said lamellas and defining a radial air gap (5) enclosing said lamellas, wherein said air gap is located at a region where said lamellas at least in fractional contact with said carbon brushes (9), and said protective shield formed of stiff and thermally conductive material, and said lamellas in the contact region with said carbon brushes form an axially adjoining cooling region wherein said adjoining cooling region is not in contact with the carbon brushes (9).