Power tool including motor shaping to reduce total harmonic distortion

Abstract

A power tools includes a battery pack interface configured to receive a removable and rechargeable battery pack and a motor. The motor includes a rotor and a stator. The rotor includes a plurality of magnets and a rotor outer surface. The outer rotor surface includes a plurality of notches. Each of the plurality of notches is positioned between adjacent magnets of the plurality of magnets. The stator includes a plurality of stator teeth configured to receive a plurality of stator windings. Each of the plurality of stator teeth includes a plurality of peaks and valleys that extend around the rotor outer surface. Each peak extends axially inward in a radial direction of the rotor, and each valley extends axially outward in the radial direction of the rotor.

Description

Attorney Docket No. 066042- 1721 -WOO 1POWER TOOL INCLUDING MOTOR SHAPING TO REDUCE TOTAL HARMONIC DISTORTIONRELATED APPLICATIONS

[0001] This application claims the benefit of U.S. Patent Application No. 63 / 723,864, filed November 22, 2024, the entire content of which is hereby incorporated by reference.FIELD

[0002] This disclosure relates to power tool motors.SUMMARY

[0003] Embodiments described herein related to power tools that include a motor that includes motor shaping. Motor shaping can include shaping of an outer surface of a rotor and / or shaping of an interior surface of stator teeth in order to reduce total harmonic distortion for the motor.

[0004] Power tools described herein include a battery pack interface configured to receive a removable and rechargeable battery pack and a motor. The motor includes a rotor and a stator. The rotor includes a plurality of magnets and a rotor outer surface. The outer rotor surface includes a plurality of notches. Each of the plurality of notches is positioned between adjacent magnets of the plurality of magnets. The stator includes a plurality of stator teeth configured to receive a plurality of stator windings. Each of the plurality of stator teeth includes a plurality of peaks and valleys that extend around the rotor outer surface. Each peak extends axially inward in a radial direction of the rotor, and each valley extends axially outward in the radial direction of the rotor.

[0005] In some aspects, the plurality of peaks and valleys each have a curved shape.

[0006] In some aspects, the curved shape is a parabolic shape.

[0007] In some aspects, the curved shape is a semi-circular shape.

[0008] In some aspects, the curved shape is an oval shape.

[0009] In some aspects, the curved shape is a polynomial shape.

[0010] In some aspects, a total harmonic distortion of the motor is approximately 6% or less.Attorney Docket No. 066042- 1721 -WOO 1

[0011] In some aspects, a total harmonic distortion of the motor is approximately 3% or less.

[0012] Power tools described herein include a battery pack interface configured to receive a removable and rechargeable battery pack, and a motor. The motor includes a rotor and a stator. The rotor includes a plurality of magnets and a rotor outer surface. The outer rotor surface includes a first set of notches and a second set of notches. The stator includes a plurality of stator teeth configured to receive a plurality of stator windings. Each of the plurality of stator teeth includes a plurality of peaks and valleys that extend around the rotor outer surface. Each peak extends axially inward in a radial direction of the rotor, and each valley extends axially outward in the radial direction of the rotor.

[0013] In some aspects, the plurality of peaks and valleys each have a curved shape.

[0014] In some aspects, the curved shape is a parabolic shape.

[0015] In some aspects, the curved shape is a semi-circular shape.

[0016] In some aspects, the curved shape is an oval shape.

[0017] In some aspects, the curved shape is a polynomial shape.

[0018] In some aspects, a total harmonic distortion of the motor is approximately 3% or less.

[0019] In some aspects, a total harmonic distortion of the motor is approximately 2.8% or less.

[0020] Power tools described herein include a battery pack interface configured to receive a removable and rechargeable battery pack, and a motor. The motor includes a rotor and a stator. The rotor includes a plurality of magnets and a rotor outer surface. The outer rotor surface includes a plurality of notches. Each of the plurality of notches is positioned between adjacent magnets of the plurality of magnets. The stator includes a plurality of stator teeth configured to receive a plurality of stator windings. Each of the plurality of stator teeth includes a plurality of peaks and valleys that extend around the rotor outer surface. Each peak extends axially inward in a radial direction of the rotor, and each valley extends axially outward in the radial direction of the rotor.

[0021] In some aspects, the plurality of peaks and valleys each have a curved shape.

[0022] In some aspects, the curved shape is a parabolic shape.Attorney Docket No. 066042- 1721 -WOO 1

[0023] In some aspects, the curved shape is a semi-circular shape.

[0024] In some aspects, the curved shape is an oval shape.

[0025] In some aspects, the curved shape is a polynomial shape.

[0026] In some aspects, a total harmonic distortion of the motor is approximately 7% or less.

[0027] In some aspects, a total harmonic distortion of the motor is approximately 3% or less.

[0028] In some aspects, each notch extends axially inward in a radial direction of the rotor.

[0029] In some aspects, the plurality of notches each have a curved shape.

[0030] In some aspects, the curved shape is a parabolic shape.

[0031] In some aspects, the curved shape is a semi-circular shape.

[0032] In some aspects, the curved shape is an oval shape.

[0033] In some aspects, the curved shape is a polynomial shape.

[0034] In some aspects, a total harmonic distortion of the motor is approximately 7% or less.

[0035] In some aspects, a total harmonic distortion of the motor is approximately 3% or less.

[0036] Before any embodiments are explained in detail, it is to be understood that the embodiments are not limited in application to the details of the configurations and arrangements of components set forth in the following description or illustrated in the accompanying drawings. The embodiments are capable of being practiced or of being carried out in various ways. Also, it is to be understood that the phraseology and terminology used herein are for the purpose of description and should not be regarded as limiting. The use of “including,” “comprising,” or “having” and variations thereof are meant to encompass the items listed thereafter and equivalents thereof as well as additional items. Unless specified or limited otherwise, the terms “mounted,” “connected,” “supported,” and “coupled” and variations thereof are used broadly and encompass both direct and indirect mountings, connections, supports, and couplings.

[0037] Unless the context of their usage unambiguously indicates otherwise, the articles “a,” “an,” and “the” should not be interpreted as meaning “one” or “only one.” Rather these articles should be interpreted as meaning “at least one” or “one or more.” Likewise, when the termsAttorney Docket No. 066042- 1721 -WOO 1“the” or “said” are used to refer to a noun previously introduced by the indefinite article “a” or “an,” “the” and “said” mean “at least one” or “one or more” unless the usage unambiguously indicates otherwise.

[0038] In addition, it should be understood that embodiments may include hardware, software, and electronic components or modules that, for purposes of discussion, may be illustrated and described as if the majority of the components were implemented solely in hardware. However, one of ordinary skill in the art, and based on a reading of this detailed description, would recognize that, in at least one embodiment, the electronic-based aspects may be implemented in software (e.g., stored on non-transitory computer-readable medium) executable by one or more processing units, such as a microprocessor and / or application specific integrated circuits (“ASICs”). As such, it should be noted that a plurality of hardware and software based devices, as well as a plurality of different structural components, may be utilized to implement the embodiments. For example, “servers,” “computing devices,” “controllers,” “processors,” etc., described in the specification can include one or more processing units, one or more computer-readable medium modules, one or more input / output interfaces, and various connections (e.g., a system bus) connecting the components.

[0039] Relative terminology, such as, for example, “about,” “approximately,” “substantially,” etc., used in connection with a quantity or condition would be understood by those of ordinary skill to be inclusive of the stated value and has the meaning dictated by the context (e.g., the term includes at least the degree of error associated with the measurement accuracy, tolerances [e.g., manufacturing, assembly, use, etc.] associated with the particular value, etc.). Such terminology should also be considered as disclosing the range defined by the absolute values of the two endpoints. For example, the expression “from about 2 to about 4” also discloses the range “from 2 to 4”. The relative terminology may refer to plus or minus a percentage (e.g., 1%, 5%, 10%) of an indicated value.

[0040] It should be understood that although certain drawings illustrate hardware and software located within particular devices, these depictions are for illustrative purposes only. Functionality described herein as being performed by one component may be performed by multiple components in a distributed manner. Likewise, functionality performed by multiple components may be consolidated and performed by a single component. In some embodiments,Attorney Docket No. 066042- 1721 -WOO 1 the illustrated components may be combined or divided into separate software, firmware and / or hardware. For example, instead of being located within and performed by a single electronic processor, logic and processing may be distributed among multiple electronic processors. Regardless of how they are combined or divided, hardware and software components may be located on the same computing device or may be distributed among different computing devices connected by one or more networks or other suitable communication links. Similarly, a component described as performing particular functionality may also perform additional functionality not described herein. For example, a device or structure that is “configured” in a certain way is configured in at least that way but may also be configured in ways that are not explicitly listed.

[0041] Accordingly, in the claims, if an apparatus, method, or system is claimed, for example, as including a controller, control unit, electronic processor, computing device, logic element, module, memory module, communication channel or network, or other element configured in a certain manner, for example, to perform multiple functions, the claim or claim element should be interpreted as meaning one or more of such elements where any one of the one or more elements is configured as claimed, for example, to make any one or more of the recited multiple functions, such that the one or more elements, as a set, perform the multiple functions collectively.

[0042] Other aspects of the disclosure will become apparent by consideration of the detailed description and accompanying drawings.BRIEF DESCRIPTION OF THE DRAWINGS

[0043] FIG. 1 illustrates a perspective view of a power tool, according to some embodiments.

[0044] FIG. 2 illustrates a block diagram of a control system of the power tool of FIG. 1, according to some embodiments.

[0045] FIG. 3 illustrates a battery pack for use with the power tool of FIG. 1, according to some embodiments.

[0046] FIG. 4 illustrates a block diagram of a control system of the battery pack of FIG. 3, according to some embodiments.

[0047] FIG. 5 illustrates a power tool motor, according to embodiments described herein.Attorney Docket No. 066042- 1721 -WOO 1

[0048] FIG. 6 illustrates a power tool motor, according to embodiments described herein.

[0049] FIG. 7 illustrates a power tool motor including motor shaping, according to embodiments described herein.

[0050] FIG. 8 illustrates a power tool motor including motor shaping, according to embodiments described herein.

[0051] FIG. 9 illustrates a power tool motor including motor shaping, according to embodiments described herein.

[0052] FIG. 10 illustrates a power tool motor including motor shaping, according to embodiments described herein.

[0053] FIG. 11 illustrates a power tool motor including motor shaping, according to embodiments described herein.

[0054] FIG. 12 illustrates a power tool motor including motor shaping, according to embodiments described herein.

[0055] FIG. 13 illustrates a power tool motor including motor shaping, according to embodiments described herein.

[0056] FIG. 14 illustrates a power tool motor including motor shaping, according to embodiments described herein.

[0057] FIG. 15 illustrates a power tool motor including motor shaping, according to embodiments described herein.

[0058] FIG. 16 illustrates a power tool motor including motor shaping, according to embodiments described herein.

[0059] FIG. 17 illustrates a power tool motor including motor shaping, according to embodiments described herein.

[0060] FIG. 18 illustrates a graph of speed, current, output power, and efficiency versus torque for the various motors described herein.

[0061] FIG. 19 illustrates a graph of back electromotive force for various motors described herein.Attorney Docket No. 066042- 1721 -WOO 1DETAILED DESCRIPTION

[0062] Embodiments described herein related to power tools that include a motor that includes motor shaping. Motor shaping can include shaping of an outer surface of a rotor and / or shaping of an interior surface of stator teeth in order to reduce total harmonic distortion for the motor.

[0063] FIG. 1 illustrates a power tool 100 including a motor (also referred to as a motor assembly). The power tool 100 is, for example, a hammer drill including a housing 102. Although FIG. 1 illustrates a hammer drill, in some embodiments, the components described herein are incorporated into other types of power tools including drill-drivers, impact drivers, impact wrenches, angle grinders, circular saws, reciprocating saws, plate compactors, core drills, string trimmers, leaf blowers, vacuums, or other applicable applications that may use field weakening for motor operation. The housing 102 includes a handle portion 104 and motor housing portion 106. The power tool 100 further includes an output driver 108 (illustrated as a chuck), a trigger 110, and a battery pack interface 112. The battery pack interface 112 is configured to mechanically and electrically connect to or receive a power tool battery pack (e.g., a removable and rechargeable battery pack). In a power tool, such as power tool 100, switching elements are selectively enabled and disabled by control signals from a controller to selectively apply power from a power source (e.g., battery pack) to drive a motor.

[0064] FIG. 2 illustrates a control system 200 for the power tool 100. The control system 200 includes a controller 202. The controller 202 is electrically and / or communicatively connected to a variety of modules or components of the power tool 100. For example, the illustrated controller 202 is electrically connected to a motor 204, a battery pack interface 206, a trigger switch 208 (connected to a trigger 210), one or more sensors or sensing circuits 212, one or more indicators 214, a user input module 216, a power input module 218, an inverter bridge or FET switching module 220 (e.g., including a plurality of switching FETs), and gate drivers 224 for driving the FET switching module 220. The controller 202 includes combinations of hardware and software that are operable to, among other things, control the operation of the power tool 100, monitor the operation of the power tool 100, activate the one or more indicators 214 (e.g., an LED), etc.Attorney Docket No. 066042- 1721 -WOO 1

[0065] The controller 202 includes a plurality of electrical and electronic components that provide power, operational control, and protection to the components and modules within the controller 202 and / or the power tool 100. For example, the controller 202 includes, among other things, a processing unit 226 (e.g., a microprocessor, a microcontroller, an electronic controller, an electronic processor, or another suitable programmable device), a memory 228, input units 230, and output units 232. The processing unit 226 includes, among other things, a control unit 234, an arithmetic logic unit (“ALU”) 236, and a plurality of registers 238, and is implemented using a known computer architecture (e.g., a modified Harvard architecture, a von Neumann architecture, etc.). The processing unit 226, the memory 228, the input units 230, and the output units 232, as well as the various modules or circuits connected to the controller 202 are connected by one or more control and / or data buses (e.g., common bus 240). The control and / or data buses are shown generally in FIG. 2 for illustrative purposes. The use of one or more control and / or data buses for the interconnection between and communication among the various modules, circuits, and components would be known to a person skilled in the art in view of the invention described herein.

[0066] In some embodiments, the controller 202 is configured to control the gate drivers 224 to drive the motor 204 using a sensored or sensorless field-oriented control (“FOC”) motor control technique.

[0067] The memory 228 is a non-transitory computer readable medium and includes, for example, a program storage area and a data storage area. The program storage area and the data storage area can include combinations of different types of memory, such as a ROM, a RAM (e.g., DRAM, SDRAM, etc.), EEPROM, flash memory, a hard disk, an SD card, or other suitable magnetic, optical, physical, or electronic memory devices. The processing unit 226 is connected to the memory 228 and executes software instructions that are capable of being stored in a RAM of the memory 228 (e.g., during execution), a ROM of the memory 228 (e.g., on a generally permanent basis), or another non-transitory computer readable medium such as another memory or a disc. Software included in the implementation of the power tool 100 can be stored in the memory 228 of the controller 202. The software includes, for example, firmware, one or more applications, program data, filters, rules, one or more program modules, and other executable instructions. The controller 202 is configured to retrieve from the memory 228 and execute,Attorney Docket No. 066042- 1721 -WOO 1 among other things, instructions related to the control processes and methods described herein. In other constructions, the controller 202 includes additional, fewer, or different components.

[0068] The battery pack interface 206 includes a combination of mechanical components (e.g., rails, grooves, latches, etc.) and electrical components (e.g., one or more terminals) configured to and operable for interfacing (e.g., mechanically, electrically, and communicatively connecting) with a battery pack. For example, power provided by a battery pack 300 (see FIG. 3) to the power tool 100 is provided through the battery pack interface 206 to the power input module 218. The power input module 218 includes combinations of active and passive components to regulate or control the power received from the battery pack 300 prior to power being provided to the controller 202. The battery pack interface 206 also supplies power to the FET switching module 220 to be switched by the switching FETs to selectively provide power to the motor 204. The battery pack interface 206 also includes, for example, a communication line 242 for providing a communication line or link between the controller 202 and the battery pack 300.

[0069] The sensing circuit 212 include one or more current sensors, one or more speed sensors, one or more Hall effect sensors, one or more temperature sensors, etc. The indicators 214 include, for example, one or more light-emitting diodes (“LEDs”). The indicators 214 can be configured to display conditions of, or information associated with, the power tool 100. For example, the indicators 214 are configured to indicate measured electrical characteristics of the power tool 100, the status of the power tool, the status the motor 204, etc. The user input module 216 is operably coupled to the controller 202 to, for example, select a forward mode of operation or a reverse mode of operation, a torque and / or speed setting for the power tool 100 (e.g., using torque and / or speed switches), etc. In some embodiments, the user input module 216 includes a combination of digital and analog input or output devices required to achieve a desired level of operation for the power tool 100, such as one or more knobs, one or more dials, one or more switches, one or more buttons, etc.

[0070] FIG. 3 illustrates a battery pack 300. The battery pack 300 includes a housing 302 and an interface portion 304 for connecting the battery pack 300 to a power tool, such as the power tool 100.Attorney Docket No. 066042- 1721 -WOO 1

[0071] FIG. 4 illustrates a control system for the battery pack 300. The control system includes a controller 400. The controller 400 is electrically and / or communicatively connected to a variety of modules or components of the battery pack 300. For example, the illustrated controller 400 is connected to one or more battery cells 402 and an interface 404 (e.g., the interface portion 304 of the battery pack 300 illustrated in FIG. 3). The controller 400 is also connected to one or more voltage sensors or voltage sensing circuits 406, one or more current sensors or current sensing circuits 408, and one or more temperature sensors or temperature sensing circuits 410. The controller 400 includes combinations of hardware and software that are operable to, among other things, control the operation of the battery pack 300, monitor a condition of the battery pack 300, enable or disable charging of the battery pack 300, enable or disable discharging of the battery pack 300, etc.

[0072] The controller 400 includes a plurality of electrical and electronic components that provide power, operational control, and protection to the components and modules within the controller 400 and / or the battery pack 300. For example, the controller 400 includes, among other things, a processing unit 412 (e.g., a microprocessor, a microcontroller, an electronic processor, an electronic controller, or another suitable programmable device), a memory 414, input units 416, and output units 418. The processing unit 412 includes, among other things, a control unit 420, an ALU 422, and a plurality of registers 424, and is implemented using a known computer architecture (e.g., a modified Harvard architecture, a von Neumann architecture, etc.). The processing unit 412, the memory 414, the input units 416, and the output units 418, as well as the various modules or circuits connected to the controller 400 are connected by one or more control and / or data buses (e.g., common bus 426). The control and / or data buses are shown generally in FIG. 4 for illustrative purposes. The use of one or more control and / or data buses for the interconnection between and communication among the various modules, circuits, and components would be known to a person skilled in the art in view of the embodiments described herein.

[0073] The memory 414 is a non-transitory computer readable medium and includes, for example, a program storage area and a data storage area. The program storage area and the data storage area can include combinations of different types of memory, such as a ROM, a RAM (e.g., DRAM, SDRAM, etc ), EEPROM, flash memory, a hard disk, an SD card, or other suitable magnetic, optical, physical, or electronic memory devices. The processing unit 412 is connectedAttorney Docket No. 066042- 1721 -WOO 1 to the memory 414 and executes software instructions that are capable of being stored in a RAM of the memory 414 (e.g., during execution), a ROM of the memory 414 (e.g., on a generally permanent basis), or another non-transitory computer readable medium such as another memory or a disc. Software included in the implementation of the battery pack 300 can be stored in the memory 414 of the controller 400. The software includes, for example, firmware, one or more applications, program data, filters, rules, one or more program modules, and other executable instructions. The controller 400 is configured to retrieve from the memory 414 and execute, among other things, instructions related to the control processes and methods described herein. In other constructions, the controller 400 includes additional, fewer, or different components.

[0074] The interface 404 includes a combination of mechanical components (e.g., rails, grooves, latches, etc.) and electrical components (e.g., one or more terminals) configured to and operable for interfacing (e.g., mechanically, electrically, and communicatively connecting) the battery pack 300 with another device (e.g., a power tool, a battery pack charger, etc.). For example, the interface 404 is configured to communicatively connect to the controller 400 via a communications line 428.

[0075] The shape of the motor 204 can be manipulated to achieve a reduced amount of total harmonic distortion for the motor 204. Total harmonic distortion is a measure of total noise (e.g., higher frequency harmonics) as compared to a fundamental sine shape. Total harmonic distortion can be expressed as a percentage and can be used to quantify an extent to which a signal deviates from a pure sinusoidal waveform. The higher the percentage of total harmonic distortion, the more noise and vibrations that the motor 204 will produce. Back electromotive force (“back -EMF”) refers to a voltage that is induced in the motor 204’ s winding due to the motor’s rotation. In an ideal motor, the back-EMF of the motor 204 is a pure sinusoid. By reducing total harmonic distortion, the back-EMF can be made to be more sinusoidal (e.g., less distortion. Total harmonic distortion is measured, for example, at no load speed for the motor 204.

[0076] FIG. 5 illustrates a motor 500 for use in the power tool 100. The motor 500 includes a stator 505, a rotor 510, a rotor shaft 515, and a plurality of stator teeth 520 which receive stator windings 525. The rotor 510 includes a plurality of magnets 530 (e.g., four magnets) and a rotor outer surface 535. The motor 500 can be considered a benchmark motor for which other motorsAttorney Docket No. 066042- 1721 -WOO 1 can be compared. The motor 500 has a total harmonic distortion of approximately three percent (3%) or less.

[0077] FIG. 6 illustrates a motor 600 for use in the power tool 100. The motor 600 includes a stator 605, a rotor 610, a rotor shaft 615, and a plurality of stator teeth 620 which receive stator windings 625. The rotor 610 includes a plurality of magnets 630 (e.g., four magnets) and a rotor outer surface 635. The motor 600 does not include any shaping of the rotor outer surface 635 or the plurality of stator teeth 620. The motor 600 has a total harmonic distortion of approximately eleven percent (11%) or less.

[0078] FIG. 7 illustrates a motor 700 for use in the power tool 100. The motor 700 includes a stator 705, a rotor 710, a rotor shaft 715, and a plurality of stator teeth 720 which receive stator windings 725. The rotor 710 includes a plurality of magnets 730 (e.g., four magnets) and a rotor outer surface 735. The motor 700 includes notches 740 on the rotor outer surface 735 of the rotor 710. The notches 740 are positioned between adjacent magnets730 in the rotor 710. Each notch 740 extends axially inward in a radial direction of the rotor 710. The notches 740 can have a curved shape (e.g., parabolic, semi-circular, oval, or another polynomial shape). The motor 700 has a total harmonic distortion of approximately thirteen percent (13%) or less.

[0079] FIG. 8 illustrates a motor 800 for use in the power tool 100. The motor 800 includes a stator 805, a rotor 810, a rotor shaft 815, and a plurality of stator teeth 820 which receive stator windings 825. The rotor 810 includes a plurality of magnets 830 (e.g., four magnets) and a rotor outer surface 835. The motor 800 includes notches 840 on the rotor outer surface 835 of the rotor 810. The notches 840 are positioned at approximately a midpoint of each magnet 830 on the outer surface 835 of the rotor 810. Each notch 840 extends axially inward in a radial direction of the rotor 810. The notches 840 can have a curved shape (e.g., parabolic, semicircular, oval, or another polynomial shape). The motor 800 has a total harmonic distortion of approximately fifteen percent (15%) or less.

[0080] FIG. 9 illustrates a motor 900 for use in the power tool 100. The motor 900 includes a stator 905, a rotor 910, a rotor shaft 915, and a plurality of stator teeth 920 which receive stator windings 925. The rotor 910 includes a plurality of magnets 930 (e g., four magnets) and a rotor outer surface 935. The motor 900 includes a first set of notches 940 and a second set of notches 945 on the rotor outer surface 935 of the rotor 910. The first set of notches 940 is positionedAttorney Docket No. 066042- 1721 -WOO 1 between adjacent magnets 930 in the rotor 910. The second set of notches 945 is positioned at approximately a midpoint of each magnet 930 on the outer surface 935 of the rotor 910. Each notch 940, 945 extends axially inward in a radial direction of the rotor 910. The notches 940, 945 can have a curved shape (e.g., parabolic, semi-circular, oval, or another polynomial shape). The motor 900 has a total harmonic distortion of approximately fourteen percent (14%) or less.

[0081] FIG. 10 illustrates a motor 1000 for use in the power tool 100. The motor 1000 includes a stator 1005, a rotor 1010, a rotor shaft 1015, and a plurality of stator teeth 1020 which receive stator windings 1025. The rotor 1010 includes a plurality of magnets 1030 (e.g., four magnets) and a rotor outer surface 1035. The motor 1000 includes a first set of notches 1040 and a second set of notches 1045 on the rotor outer surface 1035 of the rotor 1010. The first set of notches 1040 is positioned adjacent a first end of each magnet 1030 in the rotor 1010 on the rotor outer surface 1035. The second set of notches 1045 is positioned adjacent a second end of each magnet 1030 in the rotor 1010 on the rotor outer surface 1035. Therefore, each magnet 1030 has a first end adjacent to a notch 1040 and a second end adjacent a notch 1045 on the outer rotor surface 1035. Each notch 1040, 1045 extends axially inward in a radial direction of the rotor 1010. The notches 1040, 1045 can have a curved shape (e.g., parabolic, semi-circular, oval, or another polynomial shape). The motor 1000 has a total harmonic distortion of approximately eight percent (8%) or less.

[0082] FIG. 11 illustrates a motor 1100 for use in the power tool 100. The motor 1100 includes a stator 1105, a rotor 1110, a rotor shaft 1115, and a plurality of stator teeth 1120 which receive stator windings 1125. The rotor 1110 includes a plurality of magnets 1130 (e.g., four magnets) and a rotor outer surface 1135. The motor 1100 includes a first set of notches 1140 and a second set of notches 1145 on the rotor outer surface 1135 of the rotor 1110. The first set of notches 1140 is positioned adjacent a first end of each magnet 1130 in the rotor 1110 on the rotor outer surface 1135. The second set of notches 1145 is positioned adjacent a second end of each magnet 1130 in the rotor 1110 on the rotor outer surface 1135. The first set of notches 1140 includes a first notch 1140 A and a second notch 1140B. The first notch 1140 A extends further into the rotor 1110 than the second notch 1140B on the rotor outer surface 1135. The second set of notches 1145 includes a first notch 1145A and a second notch 1145B. The first notch 1145A extends further into the rotor 1110 than the second notch 1145B on the rotor outer surface 1135. Therefore, each magnet 1130 has a first end adjacent to notches 1140 and a second end adjacentAttorney Docket No. 066042- 1721 -WOO 1 to notches 1145 on the outer rotor surface 1135. Each notch 1 140, 1145 extends axially inward in a radial direction of the rotor 1110. The notches 1140, 1145 can have a curved shape (e.g., parabolic, semi-circular, oval, or another polynomial shape). The motor 1100 has a total harmonic distortion of approximately seven percent (7%) or less.

[0083] FIG. 12 illustrates a motor 1200 for use in the power tool 100. The motor 1200 includes a stator 1205, a rotor 1210, a rotor shaft 1215, and a plurality of stator teeth 1220 which receive stator windings 1225. The rotor 1210 includes a plurality of magnets 1230 (e.g., four magnets) and a rotor outer surface 1235. The motor 1200 includes cutouts 1240 on each of the plurality of stator teeth 1220. The cutouts 1240 are positioned on arms 1245 of each of the plurality of stator teeth 1220 that extend around the rotor outer surface 1235. Each cutout 1240 extends axially outward in a radial direction of the rotor 1210. The cutouts 1240 can have a curved shape (e.g., parabolic, semi-circular, oval, or another polynomial shape). The motor 1200 has a total harmonic distortion of approximately nine percent (9%) or less.

[0084] FIG. 13 illustrates a motor 1300 for use in the power tool 100. The motor 1300 includes a stator 1305, a rotor 1310, a rotor shaft 1315, and a plurality of stator teeth 1320 which receive stator windings 1325. The rotor 1310 includes a plurality of magnets 1330 (e.g., four magnets) and a rotor outer surface 1335. The motor 1300 includes peaks 1340 and valleys 1345 on each of the plurality of stator teeth 1320. The peaks 1340 and valleys 1345 extend along an interior surface of each of the plurality of stator teeth 1320 that extends around the rotor outer surface 1335. Each peak 1340 extends axially inward in a radial direction of the rotor 1310. Each valley 1345 extends axially outward in a radial direction of the rotor 1310. The peaks 1340 and valleys 1345 can each have a curved shape (e.g., parabolic, semi-circular, oval, or another polynomial shape), and combine to form an approximately sawtooth or sinusoidal shape on each of the plurality of stator teeth 1320. The motor 1300 has a total harmonic distortion of approximately six percent (6%) or less.

[0085] FIG. 14 illustrates a motor 1400 for use in the power tool 100. The motor 1400 includes a stator 1405, a rotor 1410, a rotor shaft 1415, and a plurality of stator teeth 1420 which receive stator windings 1425. The rotor 1410 includes a plurality of magnets 1430 (e.g., four magnets) and a rotor outer surface 1435. The motor 1400 includes arms 1440 on each of the plurality of stator teeth 1420 that extend around the rotor outer surface 1435. Each arm 1440 isAttorney Docket No. 066042- 1721 -WOO 1 reduced in length with respect to how much of the outer rotor surface 1435 each arm 1440 covers (e.g., compared to arms 1245 in FIG. 12). The motor 1400 has a total harmonic distortion of approximately six percent (6%) or less.

[0086] Any of the rotor and / or stator shaping techniques described herein can be combined to achieve a desirable amount of total harmonic distortion.

[0087] FIG. 15 illustrates a motor 1500 for use in the power tool 100. The motor 1500 includes a stator 1505, a rotor 1510, a rotor shaft 1515, and a plurality of stator teeth 1520 which receive stator windings 1525. The rotor 1510 includes a plurality of magnets 1530 (e.g., four magnets) and a rotor outer surface 1535. The motor 1500 includes a first set of notches 1540 and a second set of notches 1545 on the rotor outer surface 1535 of the rotor 1510 that correspond to the first set of notches 1140 and second set of notches 1145 in FIG. 11. The motor 1500 also includes peaks 1550 and valleys 1555 on each of the plurality of stator teeth 1520 that correspond to the peaks 1340 and valleys 1345 in FIG. 13. The motor 1500 has a total harmonic distortion of approximately two point eight percent (2.8%) or less.

[0088] FIG. 16 illustrates a motor 1600 for use in the power tool 100. The motor 1600 includes a stator 1605, a rotor 1610, a rotor shaft 1615, and a plurality of stator teeth 1620 which receive stator windings 1625. The rotor 1610 includes a plurality of magnets 1630 (e.g., four magnets) and a rotor outer surface 1635. The rotor outer surface 1635 corresponds to the rotor outer surface 535 of the motor 500 in FIG. 5. The motor 1600 also includes peaks 1640 and valleys 1645 on each of the plurality of stator teeth 1620 that correspond to the peaks 1340 and valleys 1345 in FIG. 13. The motor 1600 has a total harmonic distortion of approximately two point five percent (2.5%) or less.

[0089] FIG. 17 illustrates a motor 1700 for use in the power tool 100. The motor 1700 includes a stator 1705, a rotor 1710, a rotor shaft 1715, and a plurality of stator teeth 1720 which receive stator windings 1725. The rotor 1710 includes a plurality of magnets 1730 (e.g., four magnets) and a rotor outer surface 1735. The motor 1700 includes notches 1740 on the rotor outer surface 1735 of the rotor 1710 that correspond to the notches 740 of motor 700 in FIG. 7. The motor 1700 also includes peaks 1745 and valleys 1750 on each of the plurality of stator teeth 1720 that correspond to the peaks 1340 and valleys 1345 in FIG. 13. The motor 1700 has a total harmonic distortion of approximately seven percent (7%) or less.Attorney Docket No. 066042- 1721 -WOO 1

[0090] In various embodiments described herein, a total harmonic distortion of less than three percent (3%) is desirable or preferred.

[0091] FIG. 18 is a graph of speed, current, output power, and efficiency versus torque for the various motors described herein. Each of the motors described with respect to FIGS. 5-17 have similar performance.

[0092] FIG. 19 illustrates a graph of back electromotive force for various motors described herein.REPRESENTATIVE FEATURES

[0093] Representative features are set out in the following clauses, which stand alone or may be combined, in any combination, with one or more features disclosed in the text and / or drawings of the specification.Clause 1. A power tool comprising: a battery pack interface configured to receive a removable and rechargeable battery pack; and a motor including: a rotor including a plurality of magnets and a rotor outer surface, and a stator including a plurality of stator teeth configured to receive a plurality of stator windings, each of the plurality of stator teeth including a plurality of peaks and valleys that extend around the rotor outer surface, wherein each peak extends axially inward in a radial direction of the rotor, and wherein each valley extends axially outward in the radial direction of the rotor.Clause 2. The power tool of clause 1, wherein the plurality of peaks and valleys each have a curved shape.Clause 3. The power tool of clause 2, wherein the curved shape is a parabolic shape.Clause 4. The power tool of clause 2, wherein the curved shape is a semi-circular shape.Clause 5. The power tool of clause 2, wherein the curved shape is an oval shape.Clause 6. The power tool of clause 2, wherein the curved shape is a polynomial shape.Clause 7. The power tool of clause 2, wherein a total harmonic distortion of the motor is approximately 6% or less.Clause 8. The power tool of clause 7, wherein a total harmonic distortion of the motor is approximately 3% or less.Attorney Docket No. 066042- 1721 -WOO 1Clause 9. A power tool comprising: a battery pack interface configured to receive a removable and rechargeable battery pack; and a motor including: a rotor including a plurality of magnets and a rotor outer surface, the rotor outer surface including a first set of notches and a second set of notches, and a stator including a plurality of stator teeth configured to receive a plurality of stator windings, each of the plurality of stator teeth including a plurality of peaks and valleys that extend around the rotor outer surface, wherein each peak extends axially inward in a radial direction of the rotor, and wherein each valley extends axially outward in the radial direction of the rotor.Clause 10. The power tool of clause 9, wherein the plurality of peaks and valleys each have a curved shape.Clause 11. The power tool of clause 10, wherein the curved shape is a parabolic shape.Clause 12. The power tool of clause 10, wherein the curved shape is a semi-circular shape.Clause 13. The power tool of clause 10, wherein the curved shape is an oval shape.Clause 14. The power tool of clause 10, wherein the curved shape is a polynomial shape.Clause 15. The power tool of clause 10, wherein a total harmonic distortion of the motor is approximately 3% or less.Clause 16. The power tool of clause 15, wherein a total harmonic distortion of the motor is approximately 2.8% or less.Clause 17. A power tool comprising: a battery pack interface configured to receive a removable and rechargeable battery pack; and a motor including: a rotor including a plurality of magnets and a rotor outer surface, the rotor outer surface including a plurality of notches, each of the plurality of notches positioned between adjacent magnets of the plurality of magnets, and a stator including a plurality of stator teeth configured to receive a plurality of stator windings, each of the plurality of stator teeth including a plurality of peaks and valleys that extend around the rotor outer surface, wherein each peak extends axially inward in a radial direction of the rotor, and wherein each valley extends axially outward in the radial direction of the rotor.Clause 18. The power tool of clause 17, wherein the plurality of peaks and valleys each have a curved shape.Attorney Docket No. 066042- 1721 -WOO 1Clause 19. The power tool of clause 18, wherein the curved shape is a parabolic shape.Clause 20. The power tool of clause 18, wherein the curved shape is a semi-circular shape.Clause 21. The power tool of clause 18, wherein the curved shape is an oval shape.Clause 22. The power tool of clause 18, wherein the curved shape is a polynomial shape.Clause 23. The power tool of clause 18, wherein a total harmonic distortion of the motor is approximately 7% or less.Clause 24. The power tool of clause 23, wherein a total harmonic distortion of the motor is approximately 3% or less.Clause 25. The power tool of clause 18, wherein each notch extends axially inward in a radial direction of the rotor.Clause 26. The power tool of clause 25, wherein the plurality of notches each have a curved shape.Clause 27. The power tool of clause 26, wherein the curved shape is a parabolic shape.Clause 28. The power tool of clause 26, wherein the curved shape is a semi-circular shape.Clause 29. The power tool of clause 26, wherein the curved shape is an oval shape.Clause 30. The power tool of clause 26, wherein the curved shape is a polynomial shape.Clause 31. The power tool of clause 26, wherein a total harmonic distortion of the motor is approximately 7% or less.Clause 32. The power tool of clause 31, wherein a total harmonic distortion of the motor is approximately 3% or less.

[0094] Thus, embodiments described herein provide power tool motors including motor shaping. Although the disclosure has been described in detail with reference to certain preferred embodiments, variations and modifications exist within the scope and spirit of one or more independent aspects of the disclosure as described. Various features and advantages are set forth in the following claims.

Claims

Attorney Docket No. 066042- 1721 -WOO 1CLAIMSWhat is claimed is:

1. A power tool comprising: a battery pack interface configured to receive a removable and rechargeable battery pack; and a motor including: a rotor including a plurality of magnets and a rotor outer surface, and a stator including a plurality of stator teeth configured to receive a plurality of stator windings, each of the plurality of stator teeth including a plurality of peaks and valleys that extend around the rotor outer surface, wherein each peak extends axially inward in a radial direction of the rotor, and wherein each valley extends axially outward in the radial direction of the rotor.

2. The power tool of claim 1, wherein the plurality of peaks and valleys each have a curved shape.

3. The power tool of claim 2, wherein the curved shape is a parabolic shape.

4. The power tool of claim 2, wherein the curved shape is a semi-circular shape.

5. The power tool of claim 2, wherein the curved shape is an oval shape.

6. The power tool of claim 2, wherein the curved shape is a polynomial shape.

7. The power tool of claim 2, wherein a total harmonic distortion of the motor is approximately 6% or less.

8. The power tool of claim 7, wherein a total harmonic distortion of the motor is approximately 3% or less.Attorney Docket No. 066042- 1721 -WOO 19. A power tool comprising: a battery pack interface configured to receive a removable and rechargeable battery pack; and a motor including: a rotor including a plurality of magnets and a rotor outer surface, the rotor outer surface including a first set of notches and a second set of notches, and a stator including a plurality of stator teeth configured to receive a plurality of stator windings, each of the plurality of stator teeth including a plurality of peaks and valleys that extend around the rotor outer surface, wherein each peak extends axially inward in a radial direction of the rotor, and wherein each valley extends axially outward in the radial direction of the rotor.

10. The power tool of claim 9, wherein the plurality of peaks and valleys each have a curved shape.

11. The power tool of claim 10, wherein the curved shape is a parabolic shape.

12. The power tool of claim 10, wherein the curved shape is a semi-circular shape.

13. The power tool of claim 10, wherein the curved shape is an oval shape.

14. The power tool of claim 10, wherein the curved shape is a polynomial shape.

15. The power tool of claim 10, wherein a total harmonic distortion of the motor is approximately 3% or less.

16. The power tool of claim 15, wherein a total harmonic distortion of the motor is approximately 2.8% or less.Attorney Docket No. 066042- 1721 -WOO 117. A power tool comprising: a battery pack interface configured to receive a removable and rechargeable battery pack; and a motor including: a rotor including a plurality of magnets and a rotor outer surface, the rotor outer surface including a plurality of notches, each of the plurality of notches positioned between adjacent magnets of the plurality of magnets, and a stator including a plurality of stator teeth configured to receive a plurality of stator windings, each of the plurality of stator teeth including a plurality of peaks and valleys that extend around the rotor outer surface, wherein each peak extends axially inward in a radial direction of the rotor, and wherein each valley extends axially outward in the radial direction of the rotor.

18. The power tool of claim 17, wherein the plurality of peaks and valleys each have a curved shape.

19. The power tool of claim 18, wherein the curved shape is a parabolic shape.

20. The power tool of claim 18, wherein the curved shape is a semi-circular shape.

21. The power tool of claim 18, wherein the curved shape is an oval shape.

22. The power tool of claim 18, wherein the curved shape is a polynomial shape.

23. The power tool of claim 18, wherein a total harmonic distortion of the motor is approximately 7% or less.

24. The power tool of claim 23, wherein a total harmonic distortion of the motor is approximately 3% or less.Attorney Docket No. 066042- 1721 -WOO 125. The power tool of claim 18, wherein each notch extends axially inward in a radial direction of the rotor.

26. The power tool of claim 25, wherein the plurality of notches each have a curved shape.

27. The power tool of claim 26, wherein the curved shape is a parabolic shape.

28. The power tool of claim 26, wherein the curved shape is a semi-circular shape.

29. The power tool of claim 26, wherein the curved shape is an oval shape.

30. The power tool of claim 26, wherein the curved shape is a polynomial shape.

31. The power tool of claim 26, wherein a total harmonic distortion of the motor is approximately 7% or less.

32. The power tool of claim 31, wherein a total harmonic distortion of the motor is approximately 3% or less.

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