Thin DC brushless motor having an air gap formed therein

A thin brushless motor comprising:

• a magnetic base plate having an inner surface;
• a rotatable shaft supported perpendicular to said base plate;
• a stator fixed to said base plate;
• an annular hub coaxially fixed to said shaft and having an outer surface facing away from said inner surface of said base plate, an axial distance from said inner surface of said base plate to said outer surface of said hub being approximately 4.5 millimeters;
• a rotor coaxially fixed to said annular hub and comprising a first wall and a second wall, said first wall being approximately 0.3-0.4 millimeters thick and having an inner surface facing said stator and extending radially from said annular hub and parallel to said base plate, said second wall having an inner surface and extending from an outer periphery of said first wall toward said base plate thereby enclosing said stator within said first wall, said second wall and said base plate;
• and
• an annular magnet having an inner surface and an adjacent upper surface facing away from said base plate, said annular magnet being fixed to said inner surface of said second wall, said annular magnet facing an outer periphery of said stator across a gap;
• wherein an annular bent portion is formed in said first wall immediately adjacent to said annular magnet thereby creating an air gap which extends to said annular magnet and has a thickness defined as a distance between a plane including said upper surface of said annular magnet and said first wall, said air gap thickness being 0.1-0.4 millimeters, and wherein a radial distance from said shaft to said bent portion is equal to a radial distance from said shaft to said inner surface of said annular magnet.