Abstract: A system and method for reducing the cost of producing a brushless DC motor is presented. The brushless DC motor provides higher power density and efficiency with an increased tool run time. The brushless DC motor includes a rotor assembly that has an unmagnetized permanent magnet affixed to a shaft. The permanent magnet remains unmagnetized until the motor is partially assembled. A plurality of coils for producing a magnetic field are wound about the rotor assembly. The coils include end turns that enclose the rotor assembly such that the rotor assembly is not removable. Since the windings are wound with the rotor assembly already enclosed, the windings do not require large end coils to allow subsequent insertion of the rotor. Minimizing the end coils reduces the length of wire required per turn, thereby reducing the resistance of the winding.

Abstract: A system and method for reducing the cost of producing a brushless DC motor is presented. The brushless DC motor provides higher power density and efficiency with an increased tool run time. The brushless DC motor includes a rotor assembly that has an unmagnetized permanent magnet affixed to a shaft. The permanent magnet remains unmagnetized until the motor is partially assembled. A plurality of coils for producing a magnetic field are wound about the rotor assembly. The coils include end turns that enclose the rotor assembly such that the rotor assembly is not removable. Since the windings are wound with the rotor assembly already enclosed, the windings do not require large end coils to allow subsequent insertion of the rotor. Minimizing the end coils reduces the length of wire required per turn, thereby reducing the resistance of the winding.

Abstract: An improved wheelchair wheel and hub assembly is described that interposes reduction gearing between the handring or rotatable hand wheel and the drivewheel of the assembly. This gearing provides some mechanical advantage to users who may lack sufficient strength to propel themselves in a conventional wheelchair, especially in a home environment. A single speed assembly is described which is operated conventionally by rotating handrings either forward or rearward to produce a corresponding rotation of the drive wheel but, unlike conventional wheels, a complete revolution of the handring results in only a partial revolution of the drive wheel. In the hub of the assembly is a wheel locking mechanism which enables the wheel to be easily and positively locked for the safety of the user, preventing rotation of the wheel in either direction. Additionally, a ratcheting mechanism is incorporated into the hub design which can be engaged to allow forward rotation but prevent rearward rotation of the drive wheels.