Abstract: A power tool includes a brushless DC motor having a stator assembly and a rotor assembly at least a portion of which is arranged pivotably inside the stator assembly. The rotor assembly includes a rotor lamination stack housing a permanent magnets and a rotor fixedly housed inside a center portion of the lamination stack to pivot therewith. A fan may be fixedly attached to the rotor and arranged adjacent the stator assembly. The fan includes a back plate and blades longitudinally projecting from a periphery of the back plate towards the stator assembly, where a middle portion of the back plate is contoured away from an end cap of the motor to accommodate a projecting portion of the end cap. The permanent magnets may extend beyond the longitudinal length of the rotor lamination stack towards a magnet sensor to facilitate sensing of the permanent magnet via the magnet sensor.

Abstract: A power tool includes a brushless DC motor housed inside an upper body of the tool housing and a control unit housed inside a handle of the housing, the control unit including a micro-controller mounted on a control circuit board, a power unit electronically coupled to the micro-controller and mounted on a power circuit board arranged substantially parallel the control circuit board inside the handle, and a heat sink in thermal contact with the power unit. An input unit may be mounted directly on the control circuit board. An upper portion of the heat sink extending towards the upper body of the housing may include a tab protruding underneath a fan assembly of the motor to transfer heat from the power unit to the airflow created by the fan.

Abstract: A method for forming an armature for an electric motor includes: securing a lamination stack having slots therein on an armature shaft, securing a commutator on one end of the armature shaft, winding magnet wires in the slots in the lamination stack and securing ends of the magnet wires to the commutator, the magnet wires having armature lead wires that extend from the slots to the commutator; and molding plastic over the magnet wires to encase at least the armature lead wires in plastic. Alternatively and/or additionally, plastic is molded over the magnet wires to retain them in the slots and to support the armature lead wires and prevent them from vibrating when the armature rotates during operation.

Abstract: An electric motor for a power tool includes a stator and an armature disposed in the stator. The armature includes a lamination stack having slots therein; an armature shaft extending coaxially through the lamination stack; a plurality of magnet wires wound in the slots of the lamination stack; a commutator disposed on the armature shaft to which ends of the magnet wires are electrically coupled; and thermally conductive plastic at least partially encasing the magnet wires, the thermally conductive plastic having a base polymer that is a blend of at least two polymers.

Abstract: A method of manufacturing an armature for an electric motor, includes: placing a commutator and a lamination stack on an armature shaft, winding magnet wire in slots in the lamination stacks to form coils, attaching ends of the magnet wire to the commutator, and molding plastic around the magnet wire and around the shaft of the armature at ends of the lamination stack. A spinning inertia of the armature is adjusted by adjusting at least one of a mass of the plastic molded and a distribution of the plastic molded. Alternatively and/or additionally, at least one of a resonant frequency and critical speed of the armature is adjusted by adjusting at least one of a geometry of the plastic molded, the physical properties of the plastic and the mechanical properties of the plastic.

Abstract: An electric motor has a stator in which an armature is disposed. The armature has a shaft. One of the stator or the armature includes a lamination stack having slots in which magnet wires are wound, the magnet wires having a coating of heat activated adhesive. There is further provided plastic molded around the magnet wires with heat of the plastic activating the heat activated adhesive on the magnet wires during molding of the plastic to bond the magnet wires together.

Abstract: A method of manufacturing an armature for an electric motor, includes: placing a commutator and a lamination stack on an armature shaft, winding magnet wire in slots in the lamination stacks to form coils, attaching ends of the magnet wire to the commutator, and molding plastic around the magnet wire and around the shaft of the armature at ends of the lamination stack. A spinning inertia of the armature is adjusted by adjusting at least one of a mass of the plastic molded and a distribution of the plastic molded. Alternatively and/or additionally, at least one of a resonant frequency and critical speed of the armature is adjusted by adjusting at least one of a geometry of the plastic molded, the physical properties of the plastic and the mechanical properties of the plastic.

Abstract: An electric motor has a rotor and a stator. The rotor or the stator has arced permanent magnets that have essentially the same inner radius (IR) and outer radius (OR). In an aspect, the stator has a stator housing having a plurality of poles. Each pole includes a plurality of flat magnets affixed to an inner surface of the stator housing. In an aspect, flats on the outside of the stator housing key the stator assembly in a power tool housing. In an aspect, flat magnets are pre-magnetized, pre-assembled with alternating magnetic polarities, inserted into a stator housing, and remagnetized to a final, desired magnetic polarity configuration. In an aspect, pre-magnetized magnets and unmagnetized magnets are pre-assembled with unmagnetized magnets between magnetized magnets, the pre-assembled magnets inserted into a stator housing, and the unmagnetized magnets magnetized to a final, desired magnetic polarity configuration.

Abstract: A power tool includes a brushless DC motor housed inside an upper body of the tool housing and a control unit housed inside a handle of the housing, the control unit including a micro-controller mounted on a control circuit board, a power unit electronically coupled to the micro-controller and mounted on a power circuit board arranged substantially parallel the control circuit board inside the handle, and a heat sink in thermal contact with the power unit. An input unit may be mounted directly on the control circuit board. An upper portion of the heat sink extending towards the upper body of the housing may include a tab protruding underneath a fan assembly of the motor to transfer heat from the power unit to the airflow created by the fan.

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.

Abstract: An electric motor has a stator in which an armature is disposed. The armature has a shaft. One of the stator or the armature includes a lamination stack having slots in which magnet wires are wound, the magnet wires having a coating of heat activated adhesive. There is further provided plastic molded around the magnet wires with heat of the plastic activating the heat activated adhesive on the magnet wires during molding of the plastic to bond the magnet wires together.

Abstract: A method of manufacturing an armature for an electric motor, includes: placing a commutator and a lamination stack on an armature shaft, winding magnet wire in slots in the lamination stacks to form coils, attaching ends of the magnet wire to the commutator, and molding plastic around the magnet wire and around the shaft of the armature at ends of the lamination stack. A spinning inertia of the armature is adjusted by adjusting at least one of a mass of the plastic molded and a distribution of the plastic molded. Alternatively and/or additionally, at least one of a resonant frequency and critical speed of the armature is adjusted by adjusting at least one of a geometry of the plastic molded, the physical properties of the plastic and the mechanical properties of the plastic.

Abstract: A power tool includes a brushless DC motor having a stator assembly and a rotor assembly at least a portion of which is arranged pivotably inside the stator assembly. The rotor assembly includes a rotor lamination stack housing a permanent magnets and a rotor fixedly housed inside a center portion of the lamination stack to pivot therewith. A fan may be fixedly attached to the rotor and arranged adjacent the stator assembly. The fan includes a back plate and blades longitudinally projecting from a periphery of the back plate towards the stator assembly, where a middle portion of the back plate is contoured away from an end cap of the motor to accommodate a projecting portion of the end cap. The permanent magnets may extend beyond the longitudinal length of the rotor lamination stack towards a magnet sensor to facilitate sensing of the permanent magnet via the magnet sensor.

Abstract: A power tool includes a motor having a stator assembly and a rotor pivotably arranged inside the stator. The stator assembly includes a lamination stack defining a plurality of poles; a plurality of field windings each arranged at at least two opposite poles of said plurality of poles and connected together around the stator assembly; and a plurality of conductive terminals longitudinally arranged along an outer surface of the lamination stack and electrically coupled to the plurality of field windings and a power source.

Abstract: A power tool has a motor having a stator made by separately forming pole pieces and field coils. The field coils are placed over necks of the pole path pieces. An armature has an outside diameter of at least 0.625 the outside diameter of the stator is placed in the stator. The housing has a girth of 200 mm or less with the motor wound to provide a maximum watts out to housing girth ratio of at least 5 maximum watts outs to 1 mm of housing girth. The field coils may be formed so that they extend beyond pole tips of the pole pieces.

Abstract: A power tool includes a brushless DC motor having a stator and a rotor pivotably arranged inside the stator, the stator including a first winding, a second winding, and a third winding. Each winding is arranged at at least two opposite poles connected together. The stator windings may be connected in a delta configuration by electrically coupling adjacent terminals of the first and second windings, second and third windings, and third and first windings at three connection points. A baffle may be provided in parallel and adjacent to the stator, the baffle including at least one conductive routing or stamping to facilitate electrically coupling the first, second, and third windings in at least one of a delta or a wye configuration.

Abstract: A power tool has a motor having a stator made by separately forming pole pieces and field coils. The field coils are placed over necks of the pole path pieces. An armature has an outside diameter of at least 0.625 the outside diameter of the stator is placed in the stator. The housing has a girth of 200 mm or less with the motor wound to provide a maximum watts out to housing girth ratio of at least 5 maximum watts outs to 1 mm of housing girth. The field coils may be formed so that they extend beyond pole tips of the pole pieces.

Abstract: A power tool has a motor having a stator made by separately forming pole pieces, return path pieces and field coils. The field coils are placed over necks of the pole path pieces and the return path pieces are affixed to the pole pieces. An armature having an outside diameter of at least 0.625 the outside diameter of the stator is placed in the stator. The field coils may be formed so that they extend beyond pole tips of the pole pieces.

Abstract: A permanent magnet electric motor has a stator and a rotor. The stator includes a stator housing having opposed axial ends and magnets affixed to an inner surface of the stator housing, and overmold material overmolded around the plurality of magnets to securely hold the plurality of magnets to the inner surface of the stator housing. The thickness of the overmold material, as measured from the inner surface of the stator housing to an inner surface of the overmold material, is greater at edges of the magnets than at a center of the magnet.

Abstract: An armature for an electric motor has a lamination stack on a shaft with a commutator mounted on one end of the shaft. Magnet wires wound in slots in the lamination stack, the commutator and armature shaft are at least partially encapsulated in thermoset. The commutator has a commutator ring divided into a plurality of segments with slots between the segments that are filled with a second plastic when the commutator is made by molding a core of the second plastic, such as phenolic, in the commutator ring before the commutator ring is mounted on the armature shaft. Prior to molding the thermoset, the commutator ring is sealed. The seal prevents the thermoset from flowing into the slots between the commutator ring segments or over the commutator ring.