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WO2025160078A1 - Moteur à rotor externe pour un outil électrique - Google Patents

Moteur à rotor externe pour un outil électrique

Info

Publication number
WO2025160078A1
WO2025160078A1 PCT/US2025/012439 US2025012439W WO2025160078A1 WO 2025160078 A1 WO2025160078 A1 WO 2025160078A1 US 2025012439 W US2025012439 W US 2025012439W WO 2025160078 A1 WO2025160078 A1 WO 2025160078A1
Authority
WO
WIPO (PCT)
Prior art keywords
circuit board
rotor motor
stator
insulator
terminals
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Pending
Application number
PCT/US2025/012439
Other languages
English (en)
Inventor
Tyler LISEC
Abraham Sanchez
John B. Fogle
Corey L. BEAN
Kyle B. SHIELDS
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Black and Decker Inc
Original Assignee
Black and Decker Inc
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Black and Decker Inc filed Critical Black and Decker Inc
Publication of WO2025160078A1 publication Critical patent/WO2025160078A1/fr
Pending legal-status Critical Current
Anticipated expiration legal-status Critical

Links

Classifications

    • H—ELECTRICITY
    • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02K—DYNAMO-ELECTRIC MACHINES
    • H02K11/00—Structural association of dynamo-electric machines with electric components or with devices for shielding, monitoring or protection
    • H02K11/30—Structural association with control circuits or drive circuits
    • H02K11/33—Drive circuits, e.g. power electronics
    • H—ELECTRICITY
    • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02K—DYNAMO-ELECTRIC MACHINES
    • H02K1/00—Details of the magnetic circuit
    • H02K1/06—Details of the magnetic circuit characterised by the shape, form or construction
    • H02K1/22—Rotating parts of the magnetic circuit
    • H02K1/27—Rotor cores with permanent magnets
    • H02K1/2786—Outer rotors
    • H02K1/2787—Outer rotors the magnetisation axis of the magnets being perpendicular to the rotor axis
    • H02K1/2789—Outer rotors the magnetisation axis of the magnets being perpendicular to the rotor axis the rotor consisting of two or more circumferentially positioned magnets
    • H02K1/2791—Surface mounted magnets; Inset magnets
    • H—ELECTRICITY
    • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02K—DYNAMO-ELECTRIC MACHINES
    • H02K29/00—Motors or generators having non-mechanical commutating devices, e.g. discharge tubes or semiconductor devices
    • H02K29/06—Motors or generators having non-mechanical commutating devices, e.g. discharge tubes or semiconductor devices with position sensing devices
    • H02K29/08—Motors or generators having non-mechanical commutating devices, e.g. discharge tubes or semiconductor devices with position sensing devices using magnetic effect devices, e.g. Hall-plates, magneto-resistors
    • H—ELECTRICITY
    • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02K—DYNAMO-ELECTRIC MACHINES
    • H02K3/00—Details of windings
    • H02K3/46—Fastening of windings on the stator or rotor structure
    • H02K3/50—Fastening of winding heads, equalising connectors, or connections thereto
    • H—ELECTRICITY
    • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02K—DYNAMO-ELECTRIC MACHINES
    • H02K7/00—Arrangements for handling mechanical energy structurally associated with dynamo-electric machines, e.g. structural association with mechanical driving motors or auxiliary dynamo-electric machines
    • H02K7/14—Structural association with mechanical loads, e.g. with hand-held machine tools or fans
    • H02K7/145—Hand-held machine tool
    • H—ELECTRICITY
    • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02K—DYNAMO-ELECTRIC MACHINES
    • H02K1/00—Details of the magnetic circuit
    • H02K1/06—Details of the magnetic circuit characterised by the shape, form or construction
    • H02K1/12—Stationary parts of the magnetic circuit
    • H02K1/18—Means for mounting or fastening magnetic stationary parts on to, or to, the stator structures
    • H02K1/187—Means for mounting or fastening magnetic stationary parts on to, or to, the stator structures to inner stators
    • H—ELECTRICITY
    • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02K—DYNAMO-ELECTRIC MACHINES
    • H02K11/00—Structural association of dynamo-electric machines with electric components or with devices for shielding, monitoring or protection
    • H02K11/20—Structural association of dynamo-electric machines with electric components or with devices for shielding, monitoring or protection for measuring, monitoring, testing, protecting or switching
    • H02K11/21—Devices for sensing speed or position, or actuated thereby
    • H02K11/215—Magnetic effect devices, e.g. Hall-effect or magneto-resistive elements
    • H—ELECTRICITY
    • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02K—DYNAMO-ELECTRIC MACHINES
    • H02K2203/00—Specific aspects not provided for in the other groups of this subclass relating to the windings
    • H02K2203/03—Machines characterised by the wiring boards, i.e. printed circuit boards or similar structures for connecting the winding terminations
    • H—ELECTRICITY
    • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02K—DYNAMO-ELECTRIC MACHINES
    • H02K2203/00—Specific aspects not provided for in the other groups of this subclass relating to the windings
    • H02K2203/12—Machines characterised by the bobbins for supporting the windings

Definitions

  • the present disclosure relates to brushless direct current (DC) motors and more specifically to an outer-rotor motor for a cordless power tool.
  • DC direct current
  • Cordless power tools may use a DC motor to generate torque to perform a function (e.g., drive a nail). It may be desirable for the DC motor used in a cordless power tool to meet a few criteria.
  • the DC motor should be fast enough to avoid delays in the use of the power tool, powerful enough to handle a range of jobs of the power tool, small enough to fit within a hand-held housing of the power tool, and light enough to prevent weighing dow n the power tool.
  • a new DC motor design to improve any or all of these criteria may increase the usefulness of the power tool.
  • an outer-rotor motor for a power tool including: a stator assembly including: a stator body having an annular body with a plurality of teeth projecting radially outward from the annular body, an insulator coupled to the stator body, the insulator including an annular portion and terminal support posts extending from the annular portion, a plurality of terminals with each of the plurality of terminals having a body portion mounted on corresponding one of the terminal support posts, a tang extending proximate an inner surface of the body portion facing radially inward, and at least one w ire wound around the plurality of teeth to form a plurality of coils, wherein a plurality 7 of cross-over portions of the at least one wire passes over the inner surface of the body portion between the tang and the body portion of the terminal; and a circuit board coupled to the plurality of terminals to supply electric power to the plurality of coils.
  • the techniques described herein relate to an outer-rotor motor, w herein the plurality of terminals further includes a side interface, and the circuit board includes a plurality of slots, the side interface of the plurality of terminals received into the plurality of slots to make an electrical connection between the circuit board and the stator assembly.
  • the techniques described herein relate to an outer-rotor motor, wherein the side interface extends radially outward from the terminal support posts and extends beyond the annular portion of the insulator.
  • the techniques described herein relate to an outer-rotor motor, where in the circuit board includes an inner opening having a diameter that is greater than a diameter of a boundary’ region defined by the plurality of terminals, and wherein the plurality of slots is formed around the inner opening.
  • the techniques described herein relate to an outer-rotor motor, further including: a circuit board assembly including a carrier and the circuit board, wherein the circuit board includes an inner opening, and the carrier includes a plurality of snaps arranged to make a snap connection with the insulator to fix the circuit board to the insulator.
  • each of the plurality of snaps includes a body portion and a hook
  • the circuit board includes a plurality of cutouts proximate the inner opening through which the bodyportion of the plurality of snaps penetrates.
  • the techniques described herein relate to an outer-rotor motor, wherein the carrier has a larger diameter than the inner opening such that the carrier sits around an inner edge of the inner opening.
  • the techniques described herein relate to an outer-rotor motor, wherein a first subset of the plurality- of terminal support posts includes a plurality- of recesses that engages the plurality of snaps.
  • the techniques described herein relate to an outer-rotor motor, wherein the carrier includes a plurality of axial posts and a second subset of the plurality of terminal support posts includes a plurality of openings to receive the plurality- of axial posts.
  • the techniques described herein relate to an outer-rotor motor, wherein the second subset of the plurality of terminal support posts includes a plurality of axial stop members that engage the plurality- of axial posts to axially constrain the circuit board assembly relative to the insulator. [0014] In some aspects, the techniques described herein relate to an outer-rotor motor, wherein the circuit board radially surrounds at least a portion of the body portion of the plurality of terminals.
  • the techniques described herein relate to an outer-rotor motor, further including a rotor assembly including a plurality of permanent magnets arranged along a circular perimeter having a rotor inner-diameter that is greater than the stator outerdiameter.
  • the techniques described herein relate to an outer-rotor motor, further including at least one magnetic sensor mounted on the circuit board and configured to magnetically sense a magnetic flux of the plurality of permanent magnets, wherein an axial distance between an axial end of the plurality of permanent magnets and the at least one magnetic sensor is in the range of approximately 1.5 mm to 2.5 mm.
  • the techniques described herein relate to an outer-rotor motor, wherein the inner surface of the body portion of the plurality of terminals torsions the at least one wire such that a first wrap of the at least one wire around one of the plurality of stator teeth is nested to an outer surface of the annular body of the stator body.
  • an outer-rotor motor for a power tool including: a stator assembly including: a stator body having an annular body with a plurality of teeth projecting radially outward from the annular body, an insulator coupled to the stator body, the insulator including an annular portion and terminal support posts extending from the annular portion, a plurality of terminals with each of the plurality of terminals having a body portion mounted on corresponding one of the terminal support posts and a tang, and at least one wire wound around the plurality of teeth to form a plurality of coils, wherein a plurality of cross-over portions of the at least one wire passes in contact with the tang; and a circuit board coupled to the plurality of terminals to supply electric power to the plurality of coils, wherein the circuit board radially surrounds at least a portion of the body portion of the plurality of terminals.
  • the techniques described herein relate to an outer-rotor motor, wherein the plurality of terminals further includes a side interface, and the circuit board includes a plurality of slots, the side interface of the plurality of terminals received into the plurality of slots to make an electrical connection between the circuit board and the stator assembly.
  • the techniques described herein relate to an outer-rotor motor, wherein the side interface extends radially outward from the terminal support posts and extends beyond the annular portion of the insulator.
  • the techniques described herein relate to an outer-rotor motor, where in the circuit board includes an inner opening having a diameter that is greater than a diameter of a boundary' region defined by the plurality' of terminals, and wherein the plurality' of slots is formed around the inner opening.
  • an outer-rotor motor further including: a circuit board assembly including a carrier and the circuit board, wherein the circuit board includes an inner opening, and the carrier includes a plurality of snaps arranged to make a snap connection with the insulator to fix the circuit board to the insulator.
  • each of the plurality 7 of snaps includes a body portion and a hook
  • the circuit board includes a plurality 7 of cutouts proximate the inner opening through which the body portion of the plurality of snaps penetrates.
  • the techniques described herein relate to an outer-rotor motor, wherein the carrier has a larger diameter than the inner opening such that the earner sits around an inner edge of the inner opening.
  • the techniques described herein relate to an outer-rotor motor, wherein a first subset of the plurality 7 of terminal support posts includes a plurality of recesses that engages the plurality 7 of snaps.
  • the techniques described herein relate to an outer-rotor motor, wherein the carrier includes a plurality of axial posts and a second subset of the plurality 7 of terminal support posts includes a plurality of openings to receive the plurality of axial posts.
  • the techniques described herein relate to an outer-rotor motor, wherein the second subset of the plurality of terminal support posts includes a plurality of axial stop members that engage the plurality of axial posts to axially constrain the circuit board assembly relative to the insulator.
  • the techniques described herein relate to an outer-rotor motor, wherein for each of the plurality 7 of terminals, the tang is folded over an inner surface of the body portion facing radially inward, and the plurality of cross-over portion of the at least one wire passes over the inner surface of the body portion and captured by the tang.
  • the techniques described herein relate to an outer-rotor motor, further including a rotor assembly including a plurality of permanent magnets arranged along a circular perimeter having a rotor inner-diameter that is greater than the stator outerdiameter.
  • the techniques described herein relate to an outer-rotor motor, further including at least one magnetic sensor mounted on the circuit board and configured to magnetically sense a magnetic flux of the plurality of permanent magnets, wherein an axial distance between an axial end of the plurality of permanent magnets and the at least one magnetic sensor is in the range of approximately 1.5 mm to 2.5 mm.
  • an outer-rotor motor for a power tool including: a stator assembly including: a stator body having an annular body with a plurality of teeth projecting radially outward from the annular body, an insulator coupled to the stator body, the insulator including an annular portion, and at least one wire w ound around the plurality of teeth to form a plurality of coils; and a circuit board mounted on the annular portion of the insulator and including: a center opening defining an inner periphery’, and a plurality' of notches extending through the inner periphery' into the circuit board periphery', wherein the plurality of notches receives end portions of the at least one wire therein proximate the annular portion of the insulator to make direct electrical coupling to the circuit board.
  • the techniques described herein relate to an outer-rotor motor, wherein the circuit board includes an outer diameter that is smaller than an outer diameter of the stator.
  • the techniques described herein relate to an outer-rotor motor, further including at least one magnetic sensor mounted on the circuit board and configured to magnetically sense a magnetic flux of the plurality’ of permanent magnets, wherein the circuit board includes an outer diameter that is smaller than an outer diameter of the stator.
  • the techniques described herein relate to an outer-rotor motor, wherein an axial distance betw een an axial end of the plurality of permanent magnets and the at least one magnetic sensor is in the range of approximately 1.5 mm to 2.5 mm.
  • the techniques described herein relate to an outer-rotor motor, wherein the insulator includes a plurality’ of posts extending from the annular portion, and wherein the circuit board includes a plurality of ribs extending into the opening, wherein the plurality of ribs includes a plurality of post holes that receive the plurality of posts.
  • the techniques described herein relate to an outer-rotor motor, wherein the insulator further includes a plurality of tabs extending from the annular portion, wherein the plurality of tabs engage a portion of the inner periphery of the circuit board to firmly support the circuit board on the insulator.
  • the techniques described herein relate to an outer-rotor motor, wherein the plurality of pins is heat staked to rotationally secure the circuit board to the stator assembly.
  • the techniques described herein relate to an outer-rotor motor, wherein the stator assembly includes a plurality of slot gaps formed circumferentially between the plurality of coils, wherein the plurality’ of notches is axially aligned with the plurality of slot gaps.
  • the techniques described herein relate to a fastening power tool including: an outer-rotor motor including a stator assembly including a plurality of coils and a rotor supporting a plurality’ of magnets around the plurality of coils; a flywheel located around the rotor to rotate therewith; a driver assembly including a driver in selective engagement with the flywheel causing the driver to drive a fastener; and an actuator that cause the driver to come into engagement with the flywheel, wherein a ramp up speed of the outer-rotor motor from a non-rotary state to a speed of greater than or equal to approximately 1 1,000 RPM to sufficient to cause the driver the drive the fastener into a workpiece is less than or equal to 360 ms2,and a rotor inertia of the outer-rotor motor is greater than or equal to approximately 2.6x10-04 kg-m2.
  • the techniques described herein relate to a fastening power tool, wherein an outer diameter of the rotor is less than or equal to 72mm.
  • the techniques described herein relate to a fastening power tool, wherein a weight of the outer-rotor motor is less than or equal to 760g.
  • the techniques described herein relate to a fastening power tool, wherein the watts per functional volume of the outer-rotor motor is greater than or equal to 6.65 W/cc. [0043] In some aspects, the techniques described herein relate to a fastening power tool, wherein the ramp up speed relative to a weight of the outer-rotor motor is 0.55 seconds/kg or less.
  • the techniques described herein relate to a fastening power tool, wherein the stator assembly includes: a stator body having an annular body with a plurality of teeth projecting radially outward from the annular body; an insulator coupled to the stator body, the insulator including an annular portion and terminal support posts extending from the annular portion; a plurality of terminals with each of the plurality of terminals having a body portion mounted on corresponding one of the terminal support posts, a tang extending proximate an inner surface of the body portion facing radially inward; at least one wire wound around the plurality of teeth to form a plurality of coils, wherein a plurality of crossover portions of the at least one wire passes over the inner surface of the body portion between the tang and the body portion of the terminal; and a circuit board coupled to the plurality of terminals to supply electric power to the plurality of coils.
  • the techniques described herein relate to a fastening power tool, wherein the stator assembly includes: a stator body having an annular body with a plurality of teeth projecting radially outward from the annular body; an insulator coupled to the stator body, the insulator including an annular portion and terminal support posts extending from the annular portion; a plurality of terminals with each of the plurality of terminals having a body portion mounted on corresponding one of the terminal support posts and a tang; at least one wire wound around the plurality of teeth to form a plurality of coils, wherein a plurality of cross-over portions of the at least one wire passes in contact with the tang; and a circuit board coupled to the plurality of terminals to supply electric power to the plurality of coils, wherein the circuit board radially surrounds at least a portion of the body portion of the plurality of terminals.
  • the techniques described herein relate to a fastening power tool, wherein the stator assembly includes: a stator body having an annular body with a plurality of teeth projecting radially outward from the annular body; an insulator coupled to the stator body, the insulator including an annular portion; at least one wire wound around the plurality of teeth to form a plurality of coils; and a circuit board mounted on the annular portion of the insulator and including: a center opening defining an inner periphery, and a plurality of notches extending through the inner periphery into the circuit board periphery, wherein the plurality of notches receives end portions of the at least one wire therein proximate the annular portion of the insulator to make direct electrical coupling to the circuit board.
  • the techniques described herein relate to a fastening power tool, wherein the stator assembly includes a stator body having an annular body with a plurality of teeth projecting radially outward from the annular body, wherein the plurality of teeth define at least 12 slots.
  • an outer-rotor motor for a power tool including: a stator body including: a cylindrical annular ring portion having an inner cylindrical surface and an outer cylindrical surface; and a plurality of teeth positioned at regular angular intervals around the outer cylindrical surface, and directed radially outward from the outer cylindrical surface, a distal end of the plurality of teeth defining a stator outerdiameter; a wire wound around the plurality of teeth to form a plurality of coils connected in series, each coil of the plurality of coils including multiple windings of the wire around a corresponding vane; phase terminals connected to the wire between teeth, the phase terminals arranged so that two adjacent coils are between adjacent phase terminals; and a printed circuit board (PCB) coupled to the phase terminals, the printed circuit board including traces connecting the phase terminals to form a three-phase coil circuit, wherein the printed circuit board is circular and has an a PCB outer-diameter that is smaller than the stat
  • the techniques described herein relate to an outer-rotor motor, wherein the phase terminals are notches in the printed circuit board configured to hold the wire for a direct solder connection to the traces.
  • the techniques described herein relate to an outer-rotor motor, wherein the notches are at an inner diameter of the printed circuit board.
  • the techniques described herein relate to an outer-rotor motor, wherein the phase terminals are discrete metal connectors, configured to hold the wire for an indirect solder connection to the traces.
  • the techniques described herein relate to an outer-rotor motor, wherein each of the discrete metal connectors include a post portion configured for insertion in a through hole of the PCB and a catch bin portion configured to hold a portion of the wire as it passes betw een a pair of adjacent teeth.
  • the techniques described herein relate to an outer-rotor motor, wherein: the inner cylindrical surface defines a stator inner-diameter; and the phase terminals are closer to the stator inner-diameter than the stator outer-diameter.
  • the techniques described herein relate to an outer-rotor motor, wherein the phase terminals are positioned along a perimeter having a diameter that is approximately the stator inner-diameter.
  • the techniques described herein relate to an outer-rotor motor, wherein there a coil to phase terminal ratio is 2: 1.
  • the techniques described herein relate to an outer-rotor motor, wherein the three-phase coil circuit includes a first portion defined by the wire wound around the plurality of teeth and a second portion defined by the traces of the printed circuit board.
  • the techniques described herein relate to an outer-rotor motor, wherein: the plurality of coils includes 12 coils spaced at 30 degree intervals around the stator body; and the phase terminals includes 6 phase terminals spaced at 60 degree intervals around the stator body.
  • the techniques described herein relate to an outer-rotor motor, further including: a rotor assembly including a plurality' of permanent magnets arranged along a circular perimeter having a rotor inner-diameter that is greater than the stator outerdiameter: and a magnetic sensor chip coupled to the printed circuit board at a position adjacent to the wire between a stator inner-diameter and stator outer-diameter.
  • the techniques described herein relate to an outer-rotor motor, wherein the magnetic sensor chip is configured to measure an angular position of the rotor assembly based on a magnetic field generated by the plurality' of permanent magnets of the rotor assembly.
  • the techniques described herein relate to an outer-rotor motor, wherein the magnetic sensor chip is a discrete device positioned on the printed circuit board closer to the plurality' of coils than the rotor assembly.
  • the techniques described herein relate to an outer-rotor motor, wherein angular position is an angle in a range between 0 degrees and 360 degrees, an output of the magnetic sensor chip being proportional to the angle.
  • the techniques described herein relate to an outer-rotor motor, wherein the three-phase coil circuit includes three phases in a series-parallel delta configuration.
  • each phase of the three phases includes a first coil, a second coil, a third coil, and a fourth coil of the plurality of coils.
  • the techniques described herein relate to an outer-rotor motor, wherein: the first coil and the second coil are connected in series to form a first series coilpair; the third coil and the fourth coil are connected in series to form a second series coil-pair; and the first series coil-pair and the second series coil-pair are coupled in parallel.
  • the techniques described herein relate to an outer-rotor motor, wherein: the first series coil-pair and the second series coil-pair are connected at a first side to a first phase terminal, wherein the first phase terminal is coupled by the printed circuit board to a first phase input of a three phase input of the three-phase coil circuit; and the first series coil-pair and the second series coil-pair are connected at a second side to a second phase terminal, wherein the second phase terminal is coupled by the printed circuit board to a second phase input of the three phase input of the three-phase coil circuit.
  • an outer-rotor motor for a power tool including: a stator body including: a cylindrical annular ring portion having an inner cylindrical surface and an outer cylindrical surface; and a plurality 7 of teeth positioned at regular angular intervals around the outer cylindrical surface, and directed radially outward from the outer cylindrical surface, a distal end of the plurality of teeth defining a stator outerdiameter; a wire wound around the plurality of teeth to form a plurality of coils connected in series, each coil of the plurality of coils including multiple windings of the wire around a corresponding vane; and phase terminals connected to the wire between teeth, the phase terminals arranged so that two adjacent coils are between adjacent phase terminals; wherein the inner cylindrical surface defines a stator inner-diameter, and the phase terminals are closer to the stator inner-diameter than the stator outer-diameter.
  • the techniques described herein relate to an outer-rotor motor, wherein the phase terminals are positioned along a perimeter having a diameter that is approximately the stator inner-diameter.
  • the techniques described herein relate to an outer-rotor motor, further including: a printed circuit board (PCB) coupled to the phase terminals, the printed circuit board including traces connecting the phase terminals to form a three-phase coil circuit, wherein the printed circuit board is circular and has an a PCB outer-diameter that is smaller than the stator outer-diameter.
  • PCB printed circuit board
  • the techniques described herein relate to an outer-rotor motor, wherein: the three-phase coil circuit includes three phases in a series-parallel delta configuration; each phase of the three phases includes a first coil, a second coil, a third coil, and a fourth coil of the plurality of coils; the first coil and the second coil are connected in series to form a first series coil-pair; the third coil and the fourth coil are connected in series to form a second series coil-pair; and the first series coil-pair and the second series coil-pair are coupled in parallel.
  • the techniques described herein relate to an outer-rotor motor, further including: a rotor assembly including a plurality of permanent magnets arranged along a circular perimeter having a rotor inner-diameter that is greater than the stator outerdiameter; and a magnetic sensor chip coupled to the printed circuit board at a position adjacent to the stator body between the stator inner-diameter and the stator outer-diameter.
  • the techniques described herein relate to an outer-rotor motor, wherein the magnetic sensor chip is a discrete device configured positioned on the printed circuit board closer to the plurality of coils than the rotor assembly.
  • a cordless nail gun including: a flywheel configured to accelerate a hammer onto a nail; and an outer-rotor motor configured to rotate the flywheel, the outer-rotor motor including: a shaft coupled to the flywheel; a rotor assembly coupled to the shaft; and a stator assembly defining a stator outerdiameter configured to fit within a rotor inner-diameter of the rotor assembly, the stator assembly including: a wire wound around a plurality of teeth to form a plurality of coils connected in series, each coil of the plurality of coils including multiple windings of the wire around a corresponding vane; phase terminals connected to the wire between teeth, the phase terminals arranged so that two adjacent coils are between adjacent phase terminals; and a printed circuit board (PCB) coupled to the phase terminals, the printed circuit board including traces connecting the phase terminals to form a three-phase coil, wherein the printed circuit board is circular and has an
  • the techniques described herein relate to a cordless nail gun, further including: a magnetic sensor chip positioned on the printed circuit board within the stator outer-diameter, the magnetic sensor chip configured to measure an angular position of the rotor assembly based on a magnetic field generated by a plurality of permanent magnets of the rotor assembly.
  • FIG. 1 is a side, cross-sectional view of a cordless nail gun, according to a possible implementation of the present disclosure.
  • FIG. 2 is an exploded view of an outer-rotor motor according to a possible implementation of the present disclosure.
  • FIG. 3 is an exploded view of a stator assembly for the outer-rotor motor shown in FIG. 2 according to a possible implementation of the present disclosure.
  • FIG. 4A is a top view of a stator body according to a possible implementation of the present disclosure.
  • FIG. 4B is a top view of two adjacent teeth of the stator body in FIG. 4A illustrating a first possible interconnection path between coils.
  • FIG. 4C is a top view of two adjacent teeth of the stator body in FIG. 4A illustrating a second possible interconnection path between coils.
  • FIG. 5 is a cutaway view of an outer-rotor motor according to a possible implementation of the present disclosure.
  • FIG. 6 is a schematic of a three-phase coil circuit according to a possible implementation of the present disclosure.
  • FIG. 7 is a winding diagram of the three-phase coil circuit shown in FIG. 6 according to a possible implementation of the present disclosure.
  • FIG. 8 is a top view of a stator illustrating the spatial relationships between phase terminals according to a possible implementation of the present disclosure.
  • FIG. 9 is an exploded view of a connector phase-terminal assembly according to a possible implementation of the present disclosure.
  • FIG 10 is a side view of connector phase-terminal according to a possible implementation of the present disclosure.
  • FIG. 11 is a perspective view 7 of a stator including connector phase-terminals according to a possible implementation of the present disclosure.
  • FIG. 12 is a perspective view 7 a stator electrically connected according to a first possible implementation of the present disclosure.
  • FIG. 13 is an exploded view of an outer-rotor motor according to another possible implementation of the present disclosure.
  • FIG. 14 is a first exploded view of the rotor assembly and the stator assembly for the outer-rotor motor of FIG. 13.
  • FIG. 15 is a second exploded view of the rotor assembly and the stator assembly for the outer-rotor motor of FIG. 13.
  • FIG. 16 is a cross-section view of the outer-rotor motor of FIG. 13.
  • FIG. 17 is an exploded view of the stator assembly for the outer-rotor motor of
  • FIG. 18 is an exploded view of a connector phase-terminal assembly for the stator assembly of FIG. 17.
  • FIG. 19 is a perspective view of the stator assembly of FIG. 17 without wiring.
  • FIG. 20 is a perspective view of the stator assembly of FIG. 17 with wiring.
  • FIG. 21 is a front view of the stator assembly of FIG. 17.
  • FIG. 22 is a rear view of the stator assembly of FIG. 17.
  • FIG. 23 is an exploded view of the assembled stator assembly and a PCB assembly for the outer-rotor motor of FIG. 13.
  • FIG. 24 is an exploded view of the PCB assembly illustrating the PCB and the carrier of FIG. 23
  • FIG. 25 is a perspective view of the assembled PCB assembly of FIG. 24.
  • FIG. 26 is an exploded view of the assembled stator assembly and the PCB assembly for the outer-rotor motor of FIG. 13.
  • FIG. 27 is a perspective view of the assembled stator assembly and the PCB assembly for the outer-rotor motor of FIG. 13.
  • FIG. 28 is a top view of the assembled stator assembly and the PCB assembly for the outer-rotor motor of FIG. 13.
  • FIG. 29 is a side, exploded view of the stator assembly and the PCB assembly for the outer-rotor motor of FIG. 13.
  • FIG. 30 is a side view of the assembled stator assembly and the PCB assembly for the outer-rotor motor of FIG. 13.
  • FIG. 31 is top view of a PCB including notch phase-terminals according to a possible implementation of the present disclosure.
  • FIG. 32 is an exploded view illustrating a fixture for coupling the wire to the notch phase terminals according to a possible implementation of the present disclosure.
  • FIG. 33 is a perspective view a stator electrically connected according to a possible implementation of the present disclosure.
  • FIG. 34 is a side cross-sectional view of the outer rotor motor illustrating the placement of a magnetic sensor chip according to a possible implementation of the present disclosure.
  • FIG. 35 is a perspective view of a stator assembly according to another possible implementation of the present disclosure.
  • FIG. 36 is an exploded view of a fixture for coupling the wire to the stator assembly of FIG. 35.
  • FIG. 37 is an exploded view of the fixture and the stator assembly of FIG. 36 and a PCB.
  • FIG. 38 is a top, partial perspective view of the fixture and the PCB assembled to the stator assembly from FIG. 37.
  • FIG. 39 is a top, partial perspective view of the fixture and the PCB assembled to the stator assembly from FIG. 37.
  • FIG. 40 is a top view of the PCB assembled to the stator assembly of FIG. 35.
  • FIG. 41 is a front view of the stator assembly of FIG. 35.
  • FIG. 42 is a rear view of the stator assembly of FIG. 35.
  • FIG. 43 are graphs illustrating the electrical performance of the magnetic sensor chip according to possible implementations of the present disclosure.
  • FIG. 44 are tables illustrating the performance of the disclosed outer-rotor motor and another outer-rotor motor according to a possible implementation of the present disclosure.
  • a brushless direct-current (BLDC) outer-rotor motor which may be referred to herein simply as outer-rotor motor, may be used to provide the power necessary for a power tool in a small volume as a result of its configuration.
  • the outer-rotor motor includes a rotor assembly that is configured to rotate around the outer diameter of a stationary stator assembly.
  • the rotor assembly includes a plurality of permanent magnets (i.e., poles) that are positioned along a circumference surrounding a stator assembly.
  • the stator assembly includes a lurality of electro-magnets (i.e.. coils).
  • each coil When each coil is excited it produces a magnetic flux, which interacts with the magnetic flux of the poles to produce a torque on the rotor assembly.
  • Changes to the current applied to the stator coils can create a changing magnetic field that can rotate the movable rotor assembly around the fixed stator assembly.
  • the changes to the cunent may be made electronically (i.e.. electronic commutation) based on a sensed position of the rotor so that no brushes are needed.
  • the cordless nail -gun may utilize the outer-rotor motor with an integrated flywheel coupled to an outer surface of the rotor to accelerate a driver (i.e., hammer) onto a head of a nail in order to drive the nail into a work piece.
  • a driver i.e., hammer
  • RPM revolutions per minute
  • W watts
  • the size (i.e., volume) of the outer-rotor motor, the ramp time of the outer-rotor motor, and the peak power of the outer-rotor motor all contribute to the performance of the cordless nail-gun.
  • the outer-rotor motor has a few advantages (e.g., as compared to an inner rotor motor) for the cordless nail-gun but each advantage may have an associated technical problem.
  • One technical problem is providing the speed and torque necessary for driving a nail (e.g., framing nail) while minimizing the size of the outer-rotor motor.
  • An outer-rotor motor that is too large can make the cordless nail-gun less portable and less convenient compared to other technologies (e.g., pneumatic).
  • Another technical problem is electrically connecting the coils of the stator assembly for electronic commutation in a way that can withstand the harsh mechanical environment of the cordless nail -gun. Increasing the number of coils can increase the peak power but requires a more complex electronic commutation.
  • the coils of the stator assembly are connected in a complex three-phase topology so that the electronic commutation can activate/deactivate the phases in a sequence to generate a torque on the rotor assembly.
  • the three-phase topology may require connections between coils that are not physically adjacent on the stator assembly, and more coils requires more of these connections. Winding the coils on the stator assembly with slack for these connections may allow for electrical shorting and/or for the coils to loosen with movement.
  • Position sensing may require multiple sensors configured to sense the magnetic fields of multiple drive magnets affixed at different points on the rotor assembly.
  • the multiple sensors can be positioned along the path of rotation of the rotor assembly so that the drive magnets pass by each of the sensors as the rotor rotates.
  • a first output e.g., HIGH
  • a second output e.g., LOW
  • Sensing in this way can add complexity, size, and cost to the outer-rotor motor and may only provide a relative position of the rotor assembly.
  • the present disclosure describes an outer-rotor motor that addresses these technical problems to provide an outer-rotor motor having a high speed and high peak power within a small size (i. e. , volume).
  • the disclosed outer-rotor motor can improve the performance of the cordless nail-gun. It should be noted that, while the cordless nail-gun is described in detail, the disclosed techniques can be applied, either individually or in combination, to other power tools.
  • FIG. 1 depicts a perspective view of a cordless nail-gun 100 with a housing half removed, according to an embodiment.
  • the cordless nail-gun 100 shown herein includes an outer-rotor brushless DC motor (i.e., outer-rotor motor 200).
  • the rotor of the outer-rotor motor 200 is integrally formed with a flywheel 190.
  • cordless nail-gun 100 further includes a housing 112, an input unit 120 housed within a handle 114 of the housing and coupled to an actuator 122 (i.e., trigger) disposed outside the housing 112, and a control unit 170.
  • actuator 122 i.e., trigger
  • control unit 170 includes a micro-controller or other programmable control module and an inverter circuit for controlling the electronic commutation of the outer-rotor motor 200.
  • Control unit 170 is coupled to a power source (not shown), which may be a DC power source (e g., a removable battery pack) or an AC power source (e.g.. a 120V AC).
  • a power source not shown
  • Control unit 170 is also coupled to the input unit 120 via wires 174 to receive input signals indicative of actions desired by the user.
  • the control unit 170 regulates a supply of power from the power source to a stator assembly of the outer-rotor motor 200 based on a logic signal from the input unit 120.
  • Control unit 170 is coupled to three-phase terminals via lead wires 172.
  • the inverter circuit may be, for example, a three- phase inverter circuit including three high-side solid-state switches and three low-side solid- state switches.
  • the switching operation of the solid-state switches is controlled by the control unit 170, which regulates supply of electric power from the power supply to the outerrotor motor 200.
  • the cordless nail-gun 100 further includes a nosepiece assembly 130 including a contact trip mechanism 132 coupled to the housing 112, a magazine assembly 140. a driver assembly 150 including a driver 152 and a return mechanism, an activation assembly 160, and a solenoid 162, among other components.
  • actuation of the actuator 122, while contact trip mechanism 132 is in contact with a workpiece causes the solenoid 162 to engage the activation assembly 160.
  • Activation assembly 160 translates forward and engages the driver 152 to initiate driving engagement between the driver 152 and the flywheel 190.
  • the flywheel 190 includes one or more flywheel rings that form one or more grooves around the outer surface of the flywheel 190.
  • the driver 152 includes corresponding railings that engage the grooves of the flywheel. Rotation of the flywheel 190 causes the driver 152 to accelerate axially and drive a fastener (e.g., nail) into a workpiece.
  • a fastener e.g., nail
  • FIG. 2 is an exploded view of an outer-rotor motor according to a possible implementation of the present disclosure.
  • the outer-rotor motor 200 is suitable for use in the cordless nail-gun 100 described in conjunction with FIG. 1.
  • the outer-rotor motor 200 is configured to electrically excite a stator assembly 300 to rotate a rotor assembly 270 about a central axis (i.e.. shaft axis 251) shared by the stator assembly 300 and the rotor assembly 270.
  • the electrical excitation is provided from an electrical source via lead wires.
  • the outer-rotor motor 200 can include a first lead wire 241, a second lead wire 242 and a third lead wire 243.
  • the outer-rotor motor 200 further includes a shaft 250.
  • the shaft can be press fit into the stator assembly 300 to structurally pilot and support the stator assembly 300 within the rotor assembly 270 with an airgap therebetween.
  • the outer-rotor motor 200 further includes a support body 230.
  • the support body 230 may be coupled between a first end of the shaft 250 and the rotor assembly 270.
  • the support body 230 may include a radial body including an inner annular member fixedly mounted to the shaft 250, and a support bearing mounted circumferentially outside the radial body and fixed to the rotor assembly 270 to support the rotation of the rotor assembly 270 relative to the support body 230 and the shaft 250.
  • the support bearing may be axially secured to the rotor assembly 270 via a clip 210 and a wave spring 220.
  • Another bearing 260 may be coupled between a second end of the shaft 250 and the rotor assembly 270.
  • a flywheel 190 may be integrated with an outer circumferential surface of the rotor assembly 270, either by connection or fabrication, so that the flywheel 190 is rotated with the rotor assembly 270.
  • a fan 280 may be integrated with an axial end surface of the rotor assembly 270, either by connection or fabrication, so that the fan 280 is rotated with the rotor assembly 270 to generate a cooling airflow through the stator assembly 300.
  • the outer-rotor motor 200 may further include a fan baffle 290 configured to direct air moved by the fan 280 towards an exhaust port.
  • FIG. 3 is an exploded view of the stator assembly 300 for the outer-rotor motor shown in FIG 2 according to a possible implementation of the present disclosure.
  • the first lead wire 241, the second lead wire 242, and the third lead wire 243 are electrically connected (e.g., soldered) to a printed circuit board 310.
  • the printed circuit board includes traces configured to make connections between the lead wires and coils (not shown) of the stator assembly 300.
  • the printed circuit board 310 further includes at least one magnetic sensor 31 1 (e.g., magnetic sensor chip)_configured to sense a position of the rotor assembly 270 to facilitate the electrical commutation.
  • at least one magnetic sensor 31 1 e.g., magnetic sensor chip
  • three magnetic sensors 311 may be disposed at equidistant angular positions to sense the position of the rotor assembly 270.
  • the magnetic sensor 311 may be packaged as a chip including a series of discrete magnetic sensors designed for high precision detection of the rotor position.
  • the coils are formed from a wire wound around a stator body 400.
  • the stator body may be constructed from laminated metal layers in order to reduce (or prevent) eddy currents in the stator body 400 from negatively affecting the operation of the outer-rotor motor 200.
  • the stator assembly 300 further includes a first end-turn insulator 320.
  • the first end-tum insulator 320 is a non-conducting material and is configured to support the printed circuit board 310 and to prevent the wire of the coils from shorting to the printed circuit board 310 and/or stator body 400.
  • the stator assembly 300 further includes a slot insulating layer 330 to prevent the wire wound around stator body 400 from shorting to the stator body 400.
  • the slot insulating layer 330 may be a paper layer that is folded to conform with the facing surfaces between the teeth (i.e., vanes) of the stator body 400.
  • the stator assembly 300 further includes a second end-tum insulator 350.
  • the second end-tum insulator 350 is a non-conducting matenal and is configured to prevent the wire of the coils (not shown) from shorting to the stator body 400.
  • FIG. 4A is a top view of a stator body 400 according to a possible implementation of the present disclosure.
  • the stator body 400 is cylindrical with a height determined by identical metal layers, which are stacked and laminated in a direction along a lengthwise axis of the shaft 250.
  • the stator body 400 may be formed of a single metal piece.
  • the stator body is rotationally symmetric about a center 401 that is located along the shaft axis 251.
  • the stator body 400 includes an annular ring portion that includes an opening at its center that is configured to receive the shaft 250.
  • the opening is cylindrical with a shaft diameter 425.
  • the shaft diameter 425 can be comparable to a diameter of the shaft 250 to facilitate a press fit between the stator body 400 and the shaft 250.
  • the annular ring portion is between an inner cylindrical surface 420 defined by the shaft opening and an outer cylindrical surface 430.
  • the stator body 400 further includes a plurality of teeth positioned at regular intervals around the outer cylindrical surface 430 so that adjacent teeth are rotated relative to each other by an adjacent tooth angle 450.
  • Each tooth 410 i.e., vane
  • Each tooth 410 is directed radially outward from the outer cylindrical surface 430.
  • each tooth 410 is at the outer cylindrical surface 430 and a distal end 415 of each tooth 410 is at a stator outersurface 440.
  • each tooth extends radially between a stator inner-diameter 435 and a stator outer-diameter 445.
  • each slot is V-shaped with a back wall portion bordering the annular ring portion.
  • a wire wound around each tooth in succession may partially fill the plurality of slots of the stator body 400.
  • a wire may be wound multiple turns around a tooth to form a coil. In other words, each coil may include multiple windings of the wire around a corresponding vane.
  • Two coils may be formed on adjacent teeth by winding the wire a number of turns on a first tooth before winding the wire the number of turns on a second vane.
  • the stator body 400 may include 12 teeth. Accordingly, 12 coils, angularly spaced at 30-degree intervals, may be formed by winding the wire on successive teeth until the wire reaches its starting point at the first vane.
  • the 12 coils are wound in series because the wire is continuous from tooth to tooth.
  • the portion of the wire connecting adjacent coils passes through an adj acent tooth area 460 that is approximately the diameter of the back wall portion of the slot and includes the stator inner-diameter 435.
  • Positioning the wire proximate to the stator inner-diameter 435 may advantageously create a higher slot fill within each slot to increase the overall power output of the motor.
  • the coils on adjacent teeth may be wound in different directions, and because each tooth has two sides, the wire wound on adjacent teeth can be in one of three slots (SLOT O, SLOT l, SLOT 2). Accordingly, the interconnection path between adjacent coils may vary in how the wire passes through the adjacent tooth area 460.
  • FIG. 4B is a top view of two adjacent teeth of the stator body in FIG. 4A illustrating a first possible interconnection path between coils.
  • FIG. 4C is a top view of two teeth of the stator body in FIG. 4A illustrating a second possible interconnection path between coils.
  • the transitions between the coils in the stator assembly 300 may alternate between the first interconnection path type and the second interconnection path type as the wire is progresses around the stator body 400.
  • FIG. 5 is a cutaway view of an outer-rotor motor according to a possible implementation of the present disclosure.
  • the changing magnetic field generated by the plurality' of coils 540 of the stator assembly cause a plurality' of permanent magnets 530 (i.e., poles) of the rotor assembly to rotate along a direction 510.
  • the plurality of permanent magnets 530 of the rotor are positioned along by a rotor housing 520 to define circular perimeter having a rotor inner-diameter 550 that is larger than (i.e., greater than) the stator outer-diameter described above.
  • Electronic commutation and the circuit topology' of the plurality' of coils 540 can create the movement (i.e., rotation) along the direction 510.
  • the electronic commutation can include applying current to the coils in phases.
  • the 12 coils described above may be connected in three phases, and the first lead wire 241, the second lead wire 242, and the third lead wire 243 can be used to excite the three phases in a prescribed commutation sequence.
  • Each phase may be excited using a positive polarity or a negative polarity, leading to six possible commutation states.
  • a first commutation state may be a first phase with a positive polarity, which can include sourcing current into first lead wire 241 and sinking the current from the second lead wire 242.
  • a second commutation state may be the first phase with a negative polarity, which can include sourcing current into second lead wire 242 and sinking the current from the first lead wire 241.
  • the other commutation states include similar combinations of leads and polarities.
  • the coils are connected at phase terminals to form a three-phase coil circuit, with each phase coupled to one of the lead wires.
  • FIG. 6 is a schematic of a three-phase coil circuit according to a possible implementation of the present disclosure.
  • the three-phase coil circuit 600 includes thee phases in a series-parallel delta configuration.
  • a first phase 601 includes four coils (Ul, U2, U3, U4) coupled between the first lead wire 241 (i.e., U) and the second lead wire 242 (i.e., V).
  • a second phase 602 includes four coils (VI, V2, V3, V4) coupled between the second lead wire 242 and the third lead wire 243 (i.e., W).
  • a third phase 603 includes four coils (Wl, W2, W3, W4) coupled between the third lead wire 243 and the first lead wire 241.
  • the four coils of each phase include a first coil and a second coil connected in series to form a first series coil-pair, and a third coil and a fourth coil connected in series to form a second series coil pair.
  • the first phase of the three-phase coil circuit 600 includes U2 and Ul as the first series coil-pair and U3 and U4 as the second series coil-pair.
  • the second phase of the three-phase coil circuit 600 includes V2 and VI as the first series coil-pair and V3 and V4 as the second series coil-pair.
  • the second phase of the three-phase coil circuit 600 includes V2 and VI as the first series coil -pair and V3 and V4 as the second series coilpair.
  • the first series coil-pair and the second series coil-pair of each phase are coupled together in parallel.
  • phase terminals connected to the wire between teeth (e.g., in the adjacent tooth area 460) so that adjacent coils from a first portion of the stator body 400 can be coupled to adjacent coils from a second portion of the stator body.
  • a ratio of coils to phase terminals of 2 to 1 (2: 1) is provided, so there are six phase terminals needed.
  • a phase terminal may be coupled between the each of following pairs of adjacent coils (Ul. V2), (VI, W2), (Wl, U3), (U4, V3). (V4, W3), and (W4, U2).
  • the phase terminals may then be connected to form the three-phase coil circuit 600.
  • FIG. 7 is a winding diagram of the three-phase coil circuit shown in FIG. 6 according to a possible implementation of the present disclosure.
  • the teeth of the stator assembly 300 are labeled according to their corresponding coil.
  • a wire 710 is wound around the teeth in sequence the sequence: U2, Ul, V2, VI. W2, Wl. U3, U4, V3, V4, W3, W4, and back to U2.
  • Phase terminals are positioned between pairs of adjacent coils, as described above.
  • a first-phase-terminal (Ua) is connected to a first portion 731 of the wire 710 betw een coil W4 and coil U2
  • a second-phase-terminal (Vb) is connected to a second portion 732 of the wire 710 between coil Ul and coil V2
  • a third-phase-terminal (Wa) is connected to a third portion 733 of the wire 710 between coil V 1 and coil W2
  • a fourth-phase-terminal (Ub) is connected to a fourth portion 734 of the wire 710 between coil Wl and coil U3
  • a fifth-phase-terminal (Va) is connected to a fifth portion 735 of the wire 710 between coil V4 and coil W3
  • a sixth-phase-terminal (Wb) is connected to a sixth portion 736 of the wire 710 between coil V4 and coil W3.
  • a printed circuit board 720 is coupled between the phase terminals and the lead wires.
  • the printed circuit board 720 includes traces to make the additional connections needed to form the three-phase coil circuit.
  • the three-phase coil circuit includes a first portion defined by the w ire 710 wound around the plurality of teeth and a second portion defined by the traces of the printed circuit board 720.
  • the printed circuit board 720 can include a first trace 721 configured to couple the first-phase-terminal (Ua) and the fourth-phase-terminal (Ub) to the first lead wire 241 (U).
  • the printed circuit board 720 can include a second trace 722 configured to couple the second- phase-terminal (Vb) and the fifth-phase-terminal (Vb) to the second lead wire 242 (V).
  • the printed circuit board 720 can include a third trace 723 configured to couple the third-phase- terminal (Wa) and the sixth-phase-terminal (Wb) to the third lead w ire 243 (W).
  • FIG. 8 is a top view' of a stator illustrating the spatial relationships between the phase terminals according to a possible implementation of the present disclosure.
  • the phase terminals can be spaced apart by a terminal angle 810 that is approximately twice the angular separation between coils.
  • the twelve coils can be spaced at 30- degree intervals around the stator body, while the 6 phase terminals are spaced at 60-degree intervals around the stator body.
  • the printed circuit board may be made circular to efficiently connect to the phase terminals.
  • the direction of the coil winding can be a first direction (e.g., clockwise) or a second direction (e.g.. counter-clockwise).
  • the coils can be wound so that each coil is connected in series betw een a coil of a first direction and a coil of the second direction.
  • the phase terminals can be connected between coils of the same direction.
  • the traces of the printed circuit board may be used to connect (for each phase) the coils of the phase that are wound in the first direction to the coils of the phase that are wound in the second direction.
  • phase terminals may be implemented variously.
  • a phase terminal may be a connector configured to couple a portion of the wire to a trace.
  • the connector configured to connect between the trace and the wire so that the wire and the trace are coupled in an indirect connection, such as a indirect solder connection.
  • the phase terminal may be referred to as a connector phase terminal.
  • FIG. 9 is an exploded view of a connector phase-terminal assembly to a possible implementation of the present disclosure.
  • a first end-turn insulator 320 can include a terminal mount 910.
  • the terminal mount 910 is an annular (ring-shaped member) projecting from an inner body of the first end-tum insulator 320 in the direction of the circuit board, including an outer diameter that is smaller than the stator inner diameter, and a center opening for passage of the shaft.
  • the terminal mount 910 is configured to space and support a series of connectors 1000, which in turn support the printed circuit board apart from (e.g., above) the coils.
  • the terminal mount 910 may include a series of connector sockets 920 for the connectors 1000.
  • Each connector socket 920 is formed in a front face of the terminal mount 910 (facing the circuit board) along a radial direction, extending from an outer circumferential surface of the terminal mount 910 to approximately a halfway point in the direction of its center opening.
  • the connector socket 920 is configured to receive a bar portion 1040 of a connector 1000. As shown, there are six connector sockets positioned at approximately 60-degree intervals around the perimeter of the terminal mount 910. The bar portion 1040 can be press fit into the connector socket 920 to mechanically couple the phase terminal to the terminal mount 910.
  • a wire from the coil may be looped over a catch bin portion 1010 along a wire path 930.
  • the wire may be electrically coupled to the connector 1000 using laser fusing or spot welding.
  • the connector 1000 may further include an end catch-bin portion 1030 configured to accept the wire at its end of winding when it has returned to the starting coil.
  • the connector 1000 further includes a post portion 1020.
  • the post portion is configured to mate with a plated-through-hole of the printed circuit board.
  • the connected post portion 1020 may be electrically coupled to the trace by a solder connection at the printed circuit board.
  • FIG 10 is a side view of connector phase- terminal according to a possible implementation of the present disclosure.
  • the connector phase terminal can be a discrete metal (e.g., copper) connector.
  • some example dimensions of the bar portion 1040 and the post portion 1020 are shown.
  • the bar portion 1040 extends approximately perpendicularly from an edge of a rear surface of the connector 1000
  • the post portion 1020 extends approximately perpendicularly from a center point of a front surface of the connector 1000, such that bar portion 1040 and post portion 1020 are substantially parallel but offset with respect to one another.
  • Catch-bin portions 1010 and 1030 are formed as curved recesses on opposite sides of the post portion 1020 in the front surface of the connector 1000. In an example, catch-bin portion 1010 at least partially overlaps an axis of the bar portion 1040.
  • FIG. 11 is a perspective view of a stator including connector phase-terminals according to a possible implementation of the present disclosure.
  • a cross-over portion 1110 thereof passes radially-inwardly of the post portion 1020 within the catch bin portion 1010 of the connector 1000 and is electrically coupled to the connector 1000 via a laser fusing or welding process.
  • the post portion 1020 of the connector 1000 provides mounting and connections points for the printed circuit board.
  • the connectors 1000 provide phase terminals that powder delivery to the coils and interconnections between the coils, and are positioned along a perimeter that has a diameter that is approximately smaller than the stator inner-diameter (see FIG. 9).
  • the phase terminals may be closer to the stator inner-diameter than the stator outer diameter.
  • the phase terminals may be positioned on a side of the teeth closer to a center axis of the shaft 250.
  • FIG. 12 is a perspective view' a stator electrically connected according to a first possible implementation of the present disclosure.
  • the post portion 1020 of the connector 1000 is inserted into a through-hole-via 1240 of the printed circuit-board 1230.
  • the through-hole-via 1240 is plated so that the post portion 1020 can be soldered in the through-hole-via 1240.
  • the first lead wire 241, second lead wire 242, and third lead ware 243 are also connected (e.g., via solder connections) to the printed circuitboard 1230.
  • the printed circuit-board 1230 may include traces (not shown) on multiple layers.
  • the printed circuit-board 1230 is circular with an opening at the center to provide clearance for the shaft.
  • the printed circuit-board 1230 has an PCB outer-diameter 1210 that is less than (i.e., smaller than) a stator outer-diameter 1220.
  • the through-holes 1240 are closer to an inner diameter of the PCB that the outer diameter 1210 of the PCB.
  • FIGS. 13-16 illustrate an outer-rotor motor 2300 according to another possible implementation of the present disclosure.
  • FIG. 13 is an exploded view of an outer-rotor motor 2300.
  • the outer-rotor motor 2300 is suitable for use in the cordless nail-gun 100, as described above with respect to FIG. 1.
  • the outer-rotor motor 2300 includes a higher pole count and a higher slot count (e.g., 10 pole, 12 slot) than the motor illustrated in the cordless nail-gun 100 in FIG. 1 and the outer-rotor motor 2300 would replace the motor illustrated in FIG. 1.
  • the outer-rotor motor 2300 improves the cordless nail-gun 100 by reducing the ramp up time between the time that the trigger (or switch) on the cordless nail-gun 100 is pulled and the time that the outer-rotor motor 2300 gets to operating speed so that the cordless nailgun 100 can fire the next shot.
  • FIG. 44 discussed in detail below provides a table that illustrates the improvements of the outer-rotor motor 2300, which in turn improves the performance of the cordless nail-gun 100.
  • the outer-rotor motor 2300 is configured to electrically excite a stator assembly 3000 to rotate a rotor assembly 2700 about a central axis (i.e., shaft axis 2510) shared by the stator assembly 3000 and the rotor assembly 2700.
  • the electrical excitation is provided from an electrical source via lead wires.
  • the outer-rotor motor 2300 can include a first lead wire 2410, a second lead wire 2420, and a third lead wire 2430.
  • the first lead wire 2410, the second lead wire 2420, and the third lead wire 2430 are electrically connected to a printed circuit board 3100.
  • the printed circuit board 3100 includes traces configured to make connections between the lead wires and coils of the stator assembly 3000.
  • FIG. 14 is a first exploded view of the rotor assembly 2700 and the stator assembly 3000 for the outer-rotor motor 2300
  • FIG. 15 is a second exploded view of the rotor assembly 2700 and the stator assembly 3000 for the outer-rotor motor 2300
  • FIG. 16 is a cross-section view of the outer-rotor motor 2300.
  • the outer-rotor motor 2300 further includes a shaft 2500.
  • the shaft 2500 can be press fit into the stator assembly 3000 to structurally pilot and support the stator assembly 3000 within the rotor assembly 2700 with an airgap therebetween.
  • the outer-rotor motor 2300 further includes a support body 2310.
  • the support body 2310 may be coupled between a first end of the shaft 2500 and the rotor assembly 2700.
  • the support body 2310 may include a radial body including an inner annular member 2312 fixedly mounted to the shaft 2500A support bearing 2314 is mounted circumferentially outside the radial body and fixed to the rotor assembly 2700 to support the rotation of the rotor assembly 2700 relative to the support body 2310 and the shaft 2500.
  • the support bearing 2314 may be axially secured to the rotor assembly 2700 via a clip 2110 and a wave spring 2220.
  • a bearing cap 2222 may be mounted on the shaft 2500 adjacent the support body 2310 to substantially seal the end of the shaft 2500.
  • Another support bearing 2316 may be coupled between a second end of the shaft 2500 and the rotor assembly 2700.
  • a flywheel 2900 may be integrated with an outer circumferential surface of the rotor assembly 2700, either by connection or fabrication, so that the flywheel 2900 is rotated with the rotor assembly 2700.
  • a fan 2800 may be integrated with an axial end surface of the rotor assembly 2700, either by connection or fabrication, so that the fan 2800 is rotated with the rotor assembly 2700 to generate a cooling airflow through the stator assembly 3000.
  • the outer-rotor motor 2300 may further include a fan baffle 2850 configured to direct air moved by the fan 2800 towards an exhaust port.
  • the printed circuit board 3100 includes at least one sensor 3110 (e.g., a magnetic sensor chip) configured to sense a position of the rotor assembly 2700 to facilitate the electrical commutation.
  • an outer diameter of the printed circuit board 3100 may be larger than an outer diameter of the stator assembly 3000, as seen best in FIG. 14.
  • Rotor magnets 3120 are secured to the inner surface of the rotor assembly 2700, e.g., via gluing, overmolding, etc.
  • the at least one sensor 3110 is configured to directly sense the position of the rotor magnets 3120, as the rotor assembly 2700 and its magnets rotate. That is.
  • the sensor 3110 directly senses the position of the magnet 3120 as it rotates with the rotor assembly 2700.
  • the at least one sensor 3110 may be three discrete Hall sensors positioned at preset angular positions (e.g., 60 degrees apart) to cooperatively provide position signals related to an angular position of the rotor assembly 2700.
  • the at least one sensor 3100 may include Hall signals packaged into a single chip capable of providing a high resolution and accurate position signal.
  • FIGS. 17-20 illustrate the stator assembly 3000 in more detail.
  • FIG. 17 is an exploded view of the stator assembly 3000
  • FIG. 18 is an exploded view of a connector phase-terminal assembly for the stator assembly 3000
  • FIG. 19 is a perspective view of the stator assembly 3000 without wiring
  • FIG. 20 is a perspective view of the stator assembly 3000 with wiring.
  • the stator assembly 3000 includes a series of terminals 3200, which also may be referred to interchangeably as connectors, a first insulator 3300 (e.g., a first end-turn insulator), a stator body 3400, a slot insulating layer 3500, and a second insulator 3600 (e.g.. a second end-tum insulator).
  • the first insulator 3300 is a non-conducting material and is configured to support the printed circuit board 3100 and to prevent wires of the coils from shorting to the printed circuit board 3100 and/or the stator body 3400.
  • the second insulator 3600 is anon-conducting material and is configured to prevent the wire of the coils from shorting to the stator body 3400.
  • the stator body 3400 includes a plurality of teeth 3410 (each referred to individually as a tooth) that project radially outward from an annular body 3420. Each tooth 3410 provides a structure around which wire 3700 is wound.
  • the terminals 3200 and the first insulator 3300 and the engagement of the terminals 3200 on an inner diameter of the first insulator 3300 enable an improved capturing of a wire as it gets wound around the stator assembly 3000.
  • the terminals 3200 include a body portion 3210.
  • the posts 3220 include a series of teeth 3222 that work to secure the posts 3220 into the first insulator 3300, as described in more detail below.
  • the teeth 3222 may include three (3) teeth as illustrated, but in other examples the teeth 3222 may include fewer or more teeth.
  • the tang 3230 faces inward towards the inner diameter of the first insulator 3300 and makes contact with the cross-over portions of the wire.
  • the side interface 3240 engages with the printed circuit board 3100 and is oriented in a semi-radial direction or perpendicular direction with respect to the first insulator 3300.
  • the first insulator 3300 includes an annular portion 3310 that provides a surface to support terminal support posts 3320.
  • the terminal support posts 3320 project from the surface of the annular portion 3310 and are spaced around the annular portion 3310.
  • the terminal support posts 3320 include a sliding guide recess 3330 to receive the posts 3220 of the terminals 3200.
  • the teeth 3222 engage with the sliding guide recess 3330 and, once received, the posts 3220 are fixed within the sliding guide recess 3330 due to the orientation and functioning of the teeth 3222.
  • the side interface 3240 is oriented in a semi-radial or perpendicular direction with respect to the annular portion 3310. as best seen in FIG. 19.
  • the side interface 3240 extends radially outward from the terminal support posts 3320 and extends beyond the annular portion 3310 of the first insulator 3300.
  • the first insulator 3300 also includes openings 3335 between pairs of the terminal support posts 3320 with some of the openings 3335 including recesses 3340 between pairs of the terminal support posts 3320.
  • the recesses 3340 are configured to assist in securing the printed circuit board 3100 to the first insulator 3300, as described in more detail below.
  • the wire 3700 passes between the tang 3230 and the body portion 3210 on the interior surface of the body portion 3210.
  • the tang 3230 initially projects inward at an angle so that the wire 3700 may pass between the tang 3230 and the body portion 3210.
  • the winding of the wire 3700 may be started close to the inner end of the tooth 3410 making it easy to nest the wire 3700 close to the interior surface of the tooth 3410 so that the first wind of the wire 3700 starts out tightly packed to the interior surface of the tooth 3410.
  • the body portion 3210 torsions the wire 3700 such that the winding of the wire 3700 may be started close to the outer surface of the annular body 3420 of the stator body 3400, making it easy to nest the wire 3700 close to the outer surface of the annular body 3420 so that the first wind of the wire 3700 starts out tightly packed to the outer surface of the annular body 3420.
  • the tang 3230 on each of the terminals 3200 is pressed into body portion 3210 to capture the cross-over portion of the wire 3700 such that the pressed-in tang 3230 is no longer angled inward but more parallel to the body portion 3210. None of the wire 3700 penetrates into the inner opening 3010 of the stator assembly 3000.
  • FIGS. 21 and 22 illustrate a front view 7 and a rear view 7 , respectively, of the stator assembly 3000 and the cross-over wire feeding behind the tang 3230 of the terminals 3200.
  • the cross-over portion of the wire 3700 substantially overlaps the annular portion 3310 of the first insulator 3300 as it passes from one tooth to an adjacent tooth behind an intermediary- tang 3230.
  • This arrangement facilities connections between the coils in a delta-parallel configuration previously described.
  • cross-over portions between the coils that provide series connections between coils of the same phase e.g., U1 and U2 are routed over the second insulator 3600.
  • the second insulator 3600 includes a series of tabs 3602 that capture the cross-over portions of the wire and torsion the wire to increase the slot fill as described above.
  • FIGS. 23-30 illustrate the connection of the stator assembly 3000 to the printed circuit board 3100.
  • FIG. 23 is an exploded view of the assembled stator assembly 3000 and a PCB assembly 3800, where the PCB assembly 3800 includes the printed circuit board 3100 and a carrier 3850.
  • FIG. 24 is an exploded view of the PCB assembly 3800 illustrating the PCB 3100 and the carrier 3850.
  • FIG. 25 is a perspective view of the assembled PCB assembly 3800.
  • FIG. 26 is an exploded view of the assembled stator assembly 3000 and the PCB assembly 3800.
  • FIG. 27 is a perspective view of the assembled stator assembly 3000 and the PCB assembly 3800.
  • FIG. 28 is a top view of the assembled stator assembly 3000 and the PCB assembly 3800.
  • FIG. 29 is a side, exploded view of the stator assembly 3000 and the PCB assembly 3800.
  • FIG. 30 is a side view of the assembled stator assembly 3000 and the PCB assembly 3800.
  • the printed circuit board 3100 includes a generally ringshaped body defining an outer diameter and an inner diameter formed by an opening 3150.
  • the outer diameter of the circuit board 3100 greater than the outer diameter of the stator 3000, and the inner diameter of the circuit board 3100 is sized to be greater than the outer diameter of the annular portion 3310 of the first insulator 3300.
  • the inner diameter of the circuit board 3100 is greater than a peripheral boundary' formed by body portions 3210 of the terminals 3200.
  • the printed circuit board 3100 includes slots 3130 around the inner diameter of the body.
  • the side interface 3240 of the terminals 3200 project radially outwardly from body portions 3210 pas the peripheral boundary, and slide into the slots 3130 to make an electrical connection with the slots 3130, thus forming an electrical connection between the printed circuit board 3100 and the stator assembly 3000 via the terminals 3200. Traces on the printed circuit board 3100 lead into the slots 3130 to electrically couple power wires 3102 coupled to the printed circuit board 3100 to the terminals 3200. In a three-phase motor configuration, three power wires 3102 are provided to provide power from a three-phase inverter circuit to the motor. [00180] The carrier 3850 is secured to the printed circuit board 3100 to form the PCB assembly 3800.
  • the carrier 3850 is ring-shaped and includes an outer diameter that is smaller than the outer diameter of the printed circuit board 3100 and an inner diameter that is larger than the inner diameter of the printed circuit board 3100 so that the carrier 3850 sits around the inner edge of the opening 3150.
  • the printed circuit board 3100 surrounds at least a portion of the body portion 3210 of the terminals 3200.
  • the carrier 3850 then secures the printed circuit board 3100 to the first insulator 3300 of the stator assembly 3000.
  • the carrier 3850 includes snaps 3860 that are flexible, plastic members that function to secure the printed circuit board 3100 to the first insulator 3300.
  • the snaps 3860 project radially inward of the ring-shaped body of the carrier 3850.
  • Each snap 3860 includes an axial body portion 3862 and a hook 3864.
  • the printed circuit board 3100 includes cutouts 3140.
  • the cutouts 3140 are square-shaped to conform to the shape of the body portion 3862 of the snaps 3860.
  • the cutouts 3140 may be shaped differently to conform to the particular shape of the body portion 3862 of the snaps 3860.
  • the axial body portions 3862 of the snaps 3860 pass through the cutouts 3140. That is, the snaps 3860 penetrate axially through the printed circuit board 3100 to be securely coupled to the first insulator 330.
  • the first insulator 3300 includes recesses 3350 near the annular portion 3310.
  • the recesses 3350 are provided in at least a subset of the projected portions of the first insulator 3300 on which the terminal support posts 3320 are located in alignment with the openings 3350.
  • a series of slopes surface 3342 extend from the openings 3350 leading into the recesses 3350.
  • the hooks 3864 resiliently slide over the sloped surfaces 3342 and snap into the recesses 3340 to securely support the carrier 3850, and therefore the printed circuit board 3100, to the first insulator 3300.
  • the carrier 3850 includes three (3) snaps 3860. In other examples, the carrier 3850 may include a different number of snaps 3860.
  • the first insulator 3300 includes a series of axial stop members 3344.
  • Axial stop members 3344 may be provided on a subset of the projected portions of the first insulator 3300 that do not include the recesses 3350. In an example, of the six projected portions of the first insulator 3300. three axial stop member 334 and three recesses 3340 are altematingly provided.
  • the carrier 3850 also includes axial posts 3870.
  • the axial posts 3870 may be non-flexible, plastic members that function for alignment and as an axial stop for the PCB assembly 3800 when assembled to the stator assembly 3000.
  • the carrier 3850 includes three (3) axial posts 3870.
  • the carrier 3850 may include a different number of axial posts 3870.
  • the axial posts 3870 may sit in the openings 3335 to rotationally fix the carrier 3850 relative to the first insulator 3300.
  • the ends of the axial posts 3870 engage the axial stop members 334 of the first insulator 3300 to axially constrain the carrier 3850 relative to the first insulator 330.
  • engagement of the axial posts 3870 and the axial stop members 334 provides axial constraint for the carrier 3850 along a first axial direction (i.e. towards the stator), and engagement of the snaps 3860 and recesses 3340 provides axial constraint for the carrier along a second axial direction (i.e., away from the stator).
  • FIG. 30 illustrates a detail view of the engagement of the snaps 3860 and the functioning of the axial posts 3870 as a stopping mechanism for the carrier 3850 or simply a carrier stop.
  • the above-described implementation firmly and securely supports the printed circuit board 3100 to the first insulator 330 without a screw and screw boss. Since the first insulator 3300 includes a compact annular portion 3310 that predominantly supports the terminals and does not have available space for screw bosses, this arrangement is particularly advantageous.
  • the above-described implementation positions the circuit board 3100 around the terminals 3200, i.e., in radial alignment with and outwardly of the body portions 3210 of the terminals 3200.
  • This arrangement positions the circuit board 3100 in close proximity to the stator 3000, thus reducing the overall package size and positioning the at least one sensor 3110 in optimal axial distance from the rotor magnets 3120.
  • the magnet wire may be provided with a direct connection with the printed circuit board and without discrete stator terminals.
  • a phase terminal may be a feature on the printed circuit board configured to receive a portion of the wire of the coils 1402 of the stator 1400.
  • the phase terminal may be referred to as a notch phase-terminal so that the wire 3700 is captured within the profile of the annular portion 3310 of the first insulator 3300 without interfering with the slots.
  • FIG. 31 is top view of a PCB including notch phase-terminals according to a possible implementation of the present disclosure.
  • a notch 1310 i.e.. slot
  • the printed circuit board 1300 further includes a lead- wire via 1320 for each lead wire. Traces (not shown) on the printed circuitboard 1300 may connect the notch phase terminals to the appropriate lead wire to form the three-phase coil circuit (see FIG. 6).
  • This notch phase-terminal implementation may not require connects and can, therefore, be less complex, however this implementation may require special fabrication devices and methods.
  • FIG. 32 is an exploded view illustrating a fixture for coupling the wire to the notch phase terminals during the assembly process, according to a possible implementation of the present disclosure.
  • a winding fixture 1410 Before winding the coils, a winding fixture 1410 may be inserted into the shaft opening of the stator binding. The winding fixture 1410 can be used during winding so that the portions of the wire between adjacent coils can be made larger (i.e., exaggerated) by looping the wire over a turn post 1420 of the winding fixture 1410.
  • the printed circuit board 1300 may be lowered towards the stator assembly so that the wires are fit into the notches of the printed circuit board 1300.
  • the wire in the second interconnection path 462 see FIG.
  • the wire in the first interconnection path 461 may require two notches for the direct solder connection. Accordingly, the 12 coils may require 9 notch phase terminals.
  • the notches axially overlap circumferential slot gaps 1404 located between the coils 1402
  • FIG. 33 is a perspective view a stator electrically connected according to the second possible implementation of the present disclosure.
  • the wires may be cut at locations in close proximity to the surface of the circuit board 1300, soldered into their respective notches and trimmed back so that only a small trimming residue 1510 is left at each notch. After trimming the winding fixture 1410 can be removed and replace with the shaft 250.
  • FIG. 34 is a side cross-sectional view of the outer rotor motor illustrating the placement of a magnetic sensor according to a possible implementation of the present disclosure.
  • the printed circuit board 1300 includes the magnetic sensor chip 1620.
  • the magnetic sensor chip is coupled to the printed circuit board 1300 at a position that is between the stator inner-diameter 1630 and the stator outer-diameter 1640. Accordingly, the magnetic sensor chip 1300 is closer to the wire 1610 of the coils of the stator than the permanent magnets of the rotor assembly.
  • the magnetic sensor chip 1300 is located at a location that is contained within a cylindrical envelope formed by the outer circumferential surface of the stator assembly 300 and is axially aligned with at least one of the stator coils. Despite this positioning, the angle of the rotor may be accurately determined.
  • FIGS. 35-42 illustrate another possible implementation of a stator assembly 4000 using a fixture for coupling the wire to the stator assembly 4000 and then securing a printed circuit board 4100 to the stator assembly 4000 without using terminals such as, for example, terminals 3200.
  • FIG. 35 is a perspective view of a stator assembly 4000 and
  • FIG. 36 is an exploded view of a fixture 4200 for coupling the wire to the stator assembly 4000.
  • FIG. 37 is an exploded view of the fixture 4200, the stator assembly 4000. and the printed circuit board 4100.
  • FIGS. 38 and 39 are top, partial perspective views of the fixture 4200 and the printed circuit board 4100 assembled to the stator assembly stator assembly 4000.
  • FIG. 40 is a top view of the printed circuit board 4100 assembled to the stator assembly 4000.
  • FIG. 41 is a front view of the stator assembly 4000 and
  • FIG. 42 is a rear view of the stator assembly 4000.
  • the stator assembly 4000 includes a first insulator 4300 and the first insulator 4300 includes posts 4310 and tabs 4320.
  • the printed circuit board 4100 includes many of the features of printed circuit board 1300 described above, including an opening 4150 and a plurality of notches 1452 formed through the inner periphery therein that receive the magnet wire therein from the coils.
  • the printed circuit board 4100 also includes ribs 4110 and the ribs 4110 include post holes 4120.
  • the opening 4150 of the printed circuit board 4100 is slid over the fixture 4200 to engage with the stator assembly 4000.
  • the posts 4310 on the first insulator 4300 align with the post holes 4120 on the printed circuit board 4100.
  • the posts 4310 go through the post holes 4120 such that ends of the posts 4310 extend to the other side of the post holes 4120.
  • the posts 4310 protrude through the post holes 4120 and then are heat staked (i.e., melted) to secure the printed circuit board 4100 to the stator assembly 4000.
  • the posts 4310 engaged through the post holes 4120 provides rotational constraint of the printed circuit board 4100 relative to the stator assembly 4000.
  • the tabs 4320 engage the inner surface of the opening 4150 to provide radial retention such that the printed circuit board 4100 is radially fixed relative to the stator assembly 4000.
  • the posts 4310 could be opening to receive a fastener and a fastener could be passed through the post holes 4120 and secured to the opening where the posts 4310 would be.
  • the tabs 4320 are used during the winding process. That is, the tabs 4320 are oriented so that when one set of windings is complete, the wire is passed behind the tabs 4320 before proceeding to the next set of windings.
  • the outer-rotor motor includes a magnetic sensor chip (i.e., magnetic sensor integrated circuit, such as the at least one sensor 3110 previously described) configured to sense a magnetic field generated by the plurality of permanent magnets of the rotor assembly, is used determine this position.
  • the magnetic sensor chip integrally includes an array of magnetic sensors designed for high precision and high resolution sensing.
  • the magnetic sensor chip used in the disclosed outer-rotor motor is different from convention discrete magnetic sensors (e.g., Hall sensors) in a few ways.
  • the magnetic sensor chip is a discrete device that does not require a separate sense magnet to sense the position of the rotor.
  • the magnetic sensor chip may be in direct magnetic interaction with permanent magnets of the rotor assembly to sense the rotor position using the magnetic fields generated by the poles of the rotor directly.
  • the magnetic sensor chip may sense the angle of the rotor in a range.
  • the magnetic sensor chip may output a high-resolution output corresponding to an angle between 0 degrees and 360 degrees corresponding to the measured position of the rotor. This absolute measurement may be more accurate than other relative measurements.
  • the magnetic sensor chip interacts with the flux field of the rotor permanent magnets in such a way that it does not have to be in direct axial alignment with the rotor magnets to sense the position of the rotor.
  • Above-described configurations which allow mounting the circuit board in close proximity to the stator, allow for optimal positioning of the magnetic sensor chip relative to the rotor magnets.
  • FIG. 43 are graphs illustrating the electrical performance of the magnetic sensor chip as a function of its position relative to the rotor magnets, according to possible implementations of the present disclosure.
  • the graphs illustrate angle error (i.e.. the difference between the angle determined by the magnetic sensor chip and the actual rotor angle) for versus various positions.
  • the graphs illustrate that the position between closer to the coils of the stator than the magnets of the rotor has less error than otherwise.
  • angle 14 degrees
  • FIG. 44 are tables illustrating the performance of the disclosed outer-rotor motor and another outer-rotor motor according to a possible implementation of the present disclosure.
  • the disclosed device provides more peak power in a smaller volume and has a much faster ramp time compared to a conventional outer-rotor motor having fewer poles/slots (e.g., 4 pole, 6 slots).
  • a motor constructed according to the teachings of this disclosure outperforms a conventional motor of similar width and w eight by approximately 32% in peak output pow er.
  • the motor ramp time is significantly improved by over 60%.
  • a motor constructed according to the teachings of the invention provides a ramp time to 12,400 RPM of smaller than or equal to approximately 350 ms, more preferably smaller than or equal to approximately 300 ms, even more preferably smaller than or equal to approximately 275 ms. and even more preferably smaller than or equal to approximately 265 ms, for an overall motor weight (including the stator and rotor assemblies, end caps and associated components, bearings, shaft, fan baffle, and integrated flywheel) that is less than or equal to approximately 800 g, preferably less than or equal to approximately 750 g, even more preferably less than or equal to approximately 700 g.
  • the ratio of the maximum power output of the motor to the weight of the motor is greater than or equal to approximately 2.45 watts / kg, preferably greater than or equal to approximately 2.53 watts / kg, more preferably greater than or equal to approximately 2.58 watts / kg.
  • the ratio of the maximum power output of the motor to the volume of the motor is greater than or equal to approximately 6.45 watts / cc, preferably greater than or equal to approximately 6.65 watts / cc, more preferably greater than or equal to approximately 6.85 watts / cc.
  • An outer-rotor motor for a power tool comprising: a stator body including: a cylindrical annular ring portion having an inner cylindrical surface and an outer cylindrical surface; and a plurality of teeth positioned at regular angular intervals around the outer cylindrical surface, and directed radially outward from the outer cylindrical surface, a distal end of the plurality of teeth defining a stator outer-diameter; a wire wound around the plurality of teeth to form a plurality of coils connected in series, each coil of the plurality of coils including multiple windings of the wire around a corresponding vane; phase terminals connected to the wire between teeth, the phase terminals arranged so that two adjacent coils are between adjacent phase terminals; and a printed circuit board (PCB) coupled to the phase terminals, the printed circuit board including traces connecting the phase terminals to form a three-phase coil circuit, wherein the printed circuit board is circular and has an a PCB outerdiameter that is smaller than the stator outer-diameter.
  • PCB printed
  • Example 3 The outer-rotor motor according to example 2, wherein the notches are at an inner diameter of the printed circuit board.
  • Example 4 The outer-rotor motor according to example 1, wherein the phase terminals are discrete metal connectors, configured to hold the wire for an indirect solder connection to the traces.
  • Example 5 The outer-rotor motor according to example 4, wherein each of the discrete metal connectors include a post portion configured for insertion in a through hole of the PCB and a catch bin portion configured to hold a portion of the wire as it passes between a pair of adjacent teeth.
  • Example 6 The outer-rotor motor according to example 1, wherein: the inner cylindrical surface defines a stator inner-diameter; and the phase terminals are closer to the stator inner-diameter than the stator outer-diameter.
  • Example 7 The outer-rotor motor according to example 6, wherein the phase terminals are positioned along a perimeter having a diameter that is approximately the stator inner-diameter.
  • Example 8 The outer-rotor motor according to example 1, wherein there a coil to phase terminal ratio is 2: 1.
  • Example 9 The outer-rotor motor according to example 1, wherein the three- phase coil circuit includes a first portion defined by the wire wound around the plurality of teeth and a second portion defined by the traces of the printed circuit board.
  • Example 10 The outer-rotor motor according to example 1. wherein: the plurality of coils includes 12 coils spaced at 30 degree intervals around the stator body; and the phase terminals includes 6 phase terminals spaced at 60 degree intervals around the stator body.
  • Example 11 The outer-rotor motor according to example 1, further including: a rotor assembly including a plurality of permanent magnets arranged along a circular perimeter having a rotor inner-diameter that is greater than the stator outer-diameter; and a magnetic sensor chip coupled to the printed circuit board at a position adjacent to the wire between a stator inner-diameter and stator outer-diameter.
  • Example 12 The outer-rotor motor according to example 11, wherein the magnetic sensor chip is configured to measure an angular position of the rotor assembly based on a magnetic field generated by the plurality of permanent magnets of the rotor assembly.
  • Example 13 The outer-rotor motor according to example 11 , wherein the magnetic sensor chip is a discrete device configured positioned on the printed circuit board closer to the plurality of coils than the rotor assembly.
  • Example 14 The outer-rotor motor according to example 11, wherein angular position is an angle in a range between 0 degrees and 360 degrees, an output of the magnetic sensor chip being proportional to the angle.
  • Example 15 The outer-rotor motor according to example 1. wherein the three- phase coil circuit includes three phases in a series-parallel delta configuration.
  • Example 16 The outer-rotor motor according to example 15 wherein each phase of the three phases includes a first coil, a second coil, a third coil, and a fourth coil of the plurality of coils.
  • Example 17 The outer-rotor motor according to example 16, wherein: the first coil and the second coil are connected in series to form a first series coil-pair; the third coil and the fourth coil are connected in series to form a second series coil-pair; and the first series coil-pair and the second series coil-pair are coupled in parallel.
  • Example 18 The outer-rotor motor according to example 17, wherein: the first series coil-pair and the second series coil-pair are connected at a first side to a first phase terminal, wherein the first phase terminal is coupled by the printed circuit board to a first phase input of a three phase input of the three-phase coil circuit; and the first series coil-pair and the second series coil-pair are connected at a second side to a second phase terminal, wherein the second phase terminal is coupled by the printed circuit board to a second phase input of the three phase input of the three-phase coil circuit.
  • An outer-rotor motor for a power tool comprising: a stator body including: a cylindrical annular ring portion having an inner cylindrical surface and an outer cylindrical surface; and a plurality of teeth positioned at regular angular intervals around the outer cylindrical surface, and directed radially outward from the outer cylindrical surface, a distal end of the plurality of teeth defining a stator outer-diameter; a wire w ound around the plurality of teeth to form a plurality of coils connected in series, each coil of the plurality' of coils including multiple windings of the wire around a corresponding vane: and phase terminals connected to the wire between teeth, the phase terminals arranged so that two adjacent coils are between adjacent phase terminals; wherein the inner cylindrical surface defines a stator inner-diameter, and the phase terminals are closer to the stator inner-diameter than the stator outer-diameter.
  • Example 20 The outer-rotor motor according to example 19, wherein the phase terminals are positioned along a perimeter having a diameter that is approximately the stator inner-diameter.
  • Example 21 The outer-rotor motor according to example 19, further comprising: a printed circuit board (PCB) coupled to the phase terminals, the printed circuit board including traces connecting the phase terminals to form a three-phase coil circuit, wherein the printed circuit board is circular and has an a PCB outer-diameter that is smaller than the stator outer-diameter.
  • PCB printed circuit board
  • Example 22 The outer-rotor motor according to example 21, wherein: the three- phase coil circuit includes three phases in a series-parallel delta configuration; each phase of the three phases includes a first coil, a second coil, a third coil, and a fourth coil of the plurality of coils: the first coil and the second coil are connected in series to form a first series coil-pair; the third coil and the fourth coil are connected in series to form a second series coilpair; and the first series coil-pair and the second series coil-pair are coupled in parallel.
  • Example 23 The outer-rotor motor according to example 21, further including: a rotor assembly including a plurality of permanent magnets arranged along a circular perimeter having a rotor inner-diameter that is greater than the stator outer-diameter; and a magnetic sensor chip coupled to the printed circuit board at a position adjacent to the stator body between the stator inner-diameter and the stator outer-diameter.
  • a rotor assembly including a plurality of permanent magnets arranged along a circular perimeter having a rotor inner-diameter that is greater than the stator outer-diameter
  • a magnetic sensor chip coupled to the printed circuit board at a position adjacent to the stator body between the stator inner-diameter and the stator outer-diameter.
  • Example 24 The outer-rotor motor according to example 23, wherein the magnetic sensor chip is a discrete device configured positioned on the printed circuit board closer to the plurality of coils than the rotor assembly.
  • Example 25 A cordless nail gun comprising: a flywheel configured to accelerate a hammer onto a nail; and an outer-rotor motor configured to rotate the flywheel, the outerrotor motor including: a shaft coupled to the flywheel; a rotor assembly coupled to the shaft; and a stator assembly defining a stator outer-diameter configured to fit within a rotor inner- diameter of the rotor assembly, the stator assembly including: a wire wound around a plurality of teeth to form a plurality of coils connected in series, each coil of the plurality of coils including multiple windings of the wire around a corresponding vane: phase terminals connected to the wire between teeth, the phase terminals arranged so that two adjacent coils are between adjacent phase terminals; and a printed circuit board (PCB) coupled to the phase terminals, the printed circuit board including traces connecting the phase terminals to form a three-phase coil, wherein the printed circuit board is circular and has an a PCB outerdiameter that is
  • Example 26 The cordless nail gun according to example 25, further comprising: a magnetic sensor chip positioned on the printed circuit board within the stator outer-diameter, the magnetic sensor chip configured to measure an angular position of the rotor assembly based on a magnetic field generated by a plurality of permanent magnets of the rotor assembly.
  • Ranges may be expressed herein as from “about” one particular value, and/or to “about” another particular value. When such a range is expressed, an aspect includes from the one particular value and/or to the other particular value. Similarly, when values are expressed as approximations, by use of the antecedent "about,” it will be understood that the particular value forms another aspect. It will be further understood that the endpoints of each of the ranges are significant both in relation to the other endpoint, and independently of the other endpoint.
  • Some implementations may be implemented using various semiconductor processing and/or packaging techniques. Some implementations may be implemented using various types of semiconductor processing techniques associated with semiconductor substrates including, but not limited to, for example, Silicon (Si), Gallium Arsenide (GaAs), Gallium Nitride (GaN), Silicon Carbide (SiC) and/or so forth.
  • semiconductor substrates including, but not limited to, for example, Silicon (Si), Gallium Arsenide (GaAs), Gallium Nitride (GaN), Silicon Carbide (SiC) and/or so forth.
  • a singular form may, unless definitely indicating a particular case in terms of the context, include a plural form.
  • Spatially relative terms e.g., over, above, upper, under, beneath, below, lower, and so forth
  • the relative terms above and below can, respectively, include vertically above and vertically below.
  • the term adjacent can include laterally adjacent to or horizontally adjacent to.

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  • Engineering & Computer Science (AREA)
  • Power Engineering (AREA)
  • Microelectronics & Electronic Packaging (AREA)
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Abstract

L'invention concerne un moteur à rotor externe pour un outil tenu à la main, qui comprend un ensemble stator (3000) comprenant : - un corps de stator ayant un corps annulaire comportant une pluralité de dents faisant saillie radialement vers l'extérieur à partir du corps annulaire, - un isolant (3300) relié au corps de stator et comprenant une partie annulaire et des montants de support de borne (3320) s'étendant axialement, - une pluralité de bornes (3200) ayant une partie corps (3210) montée sur l'un des montants de support de borne d'isolant (3320) et un tenon (3230) s'étendant à proximité d'une surface interne de la partie corps (3210) tournée radialement vers l'intérieur, - au moins un fil (3700) enroulé autour de la pluralité de dents pour former une pluralité de bobines, des parties de croisement du ou des fils (3700) passant sur la surface interne de la partie corps (3210) entre le tenon et la partie corps de la borne et - une carte de circuit imprimé (3100) reliée auxdites bornes.
PCT/US2025/012439 2024-01-22 2025-01-21 Moteur à rotor externe pour un outil électrique Pending WO2025160078A1 (fr)

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US20120097729A1 (en) 2004-04-02 2012-04-26 Black & Decker Inc. Power take off for cordless nailer
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