Power tool motor rotor configuration

Abstract

To solve problems with the prior art.SOLUTION: A power tool includes a battery pack interface and a consequent magnetic pole motor. The battery pack interface is configured to receive a removable and rechargeable battery pack. The consequent magnetic pole motor includes: a stator including a plurality of stator teeth configured to receive a plurality of stator coils; and a rotor configured to rotate with respect to the stator. The rotor includes a first permanent magnet positioned within the rotor, a second permanent magnet positioned within the rotor, and a consequent magnetic pole located between the first permanent magnet and the second permanent magnet. The consequent magnetic pole has a length and a width. The consequent magnetic pole is made of a non-magnetic material.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] (Reference to Related Applications) This application claims the benefit of U.S. Provisional Patent Application No. 63 / 505,523, filed on June 1, 2023, the entire content of which is incorporated herein by reference.

[0002] (Technical Field) The embodiments described herein relate to motors of power tools.

Summary of the Invention

[0003] The power tool described herein includes a battery pack interface configured to receive a battery pack and a motor. The motor includes a stator including a plurality of stator teeth configured to receive a plurality of stator windings, and a rotor configured to rotate with respect to the stator. The rotor includes a first permanent magnet within the rotor, a second permanent magnet within the rotor, and a resulting magnetic pole positioned between the first permanent magnet and the second permanent magnet. The resulting magnetic pole has a length and a width. The resulting magnetic pole is made of a non-magnetic material.

[0004] In some embodiments, the first permanent magnet and the second permanent magnet are composed of rare earth metals.

[0005] In some embodiments, the motor includes a laminated stack including an inner laminated body portion and an outer laminated body portion, with a void positioned between the inner laminated body portion and the outer laminated body portion.

[0006] In some embodiments, the resulting magnetic pole is constructed from the laminated stack.

[0007] In some embodiments, the inner laminated body portion includes a first axially supporting portion, and the outer laminated body portion includes a second axially supporting portion.

[0008] In some embodiments, the rotor includes an outer diameter of approximately 22 millimeters.

[0009] In some embodiments, the rotor further includes a laminated stack, a first slot including a first magnet housing portion configured to receive a first permanent magnet, a second slot including a second magnet housing portion configured to receive a second permanent magnet, and a plurality of voids, each of which voids comprises injection-molded material.

[0010] In some embodiments, one of the multiple voids is surrounded by the outer ribs of the laminate stack.

[0011] A power tool described herein includes a battery pack interface configured to receive a battery pack and a resulting pole motor. The resulting pole motor includes a stator having a plurality of stator teeth configured to receive a plurality of stator windings and a rotor configured to rotate relative to the stator. The rotor includes a first permanent magnet in a first slot of the rotor, a second permanent magnet in a second slot of the rotor, a first resulting pole between the first permanent magnet and the second permanent magnet having a first length and a first width, and a second resulting pole between the first permanent magnet and the second permanent magnet having a second length and a second width.

[0012] In some embodiments, the first permanent magnet and the second permanent magnet are composed of rare earth metals.

[0013] In some embodiments, the rotor includes a laminated stack comprising an inner laminated portion and an outer laminated portion, wherein a void is located between the inner and outer laminated portions, and the void is surrounded by the outer ribs of the laminated stack.

[0014] In some embodiments, the first resulting magnetic pole and the second resulting magnetic pole are constructed from a laminated stack.

[0015] In some embodiments, the inner laminate portion includes a first axial support portion, and the outer laminate portion includes a second axial support portion.

[0016] In some embodiments, the rotor further includes a laminated stack, a first slot including a first magnet housing portion configured to receive a first permanent magnet, a second slot including a second magnet housing portion configured to receive a second permanent magnet, and a plurality of voids, each of which voids comprises injection-molded material, and one of the plurality of voids is surrounded by an outer rib of the laminated stack.

[0017] The resulting magnetic pole motor described herein includes a stator having a plurality of stator teeth configured to receive a plurality of stator windings, and a rotor configured to rotate around the stator. The rotor includes a laminate stack having an inner laminate portion and an outer laminate portion, a first permanent magnet located in a first slot of the laminate stack, the first slot being between the inner and outer laminate portions, a second permanent magnet located in a second slot of the laminate stack, the second slot being between the inner and outer laminate portions, a first resulting magnetic pole located between the first and second permanent magnets having a first length and a first width, a second resulting magnetic pole located between the first and second permanent magnets having a second length and a second width, and a gap located between the inner and outer laminate portions.

[0018] In some embodiments, the first resulting magnetic pole and the second resulting magnetic pole are constructed from a laminated stack.

[0019] In some embodiments, the first permanent magnet and the second permanent magnet are composed of rare earth metals, and the resulting poles of the first and second permanent magnets are constructed from a non-magnetic material.

[0020] In some embodiments, the voids are surrounded by the outer ribs of the laminate stack.

[0021] In some embodiments, the voids are filled with injection-molded material.

[0022] In some embodiments, the rotor further includes a first retaining portion configured to hold an inner laminate portion and a second retaining portion configured to hold an outer laminate portion, the first and second retaining portions being connected via a plate.

[0023] Before any embodiment is described in detail, it should be understood that this embodiment is not limited in its application to the details of the configuration and arrangement of components described below or illustrated in the accompanying drawings. Embodiments can be carried out or implemented in various ways. It should also be understood that the expressions and terms used herein are for illustrative purposes only and should not be considered limiting. The use of “including,” “comprising,” or “having,” and their variations, is intended to include the items listed below and their equivalents, as well as additional items. Unless otherwise specified or otherwise limited, the terms “mounted,” “connected,” “supported,” and “coupled,” and their variations, are used broadly and encompass both direct and indirect mounting, connection, support, and coupling.

[0024] Unless the context of their usage is clearly different, 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.” Similarly, when the aforementioned terms (“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 is clearly different.

[0025] In addition, embodiments may include hardware, software, and electronic components or modules, which, for the purposes of this discussion, may be illustrated and described as if the majority of the components were implemented solely in hardware. However, those skilled in the art will recognize, based on a reading of this detailed description, that in at least one embodiment, an electronically based aspect may be implemented in software (e.g., stored on a non-temporary computer-readable medium) executable by one or more processing units, such as microprocessors and / or application-specific integrated circuits ("ASICs"). Thus, it should be noted that multiple hardware and software-based devices, as well as multiple different structural components, may be used to implement the embodiments. For example, “servers,” “computing devices,” “controllers,” “processors,” etc., as described herein may include one or more processing units, one or more computer-readable medium modules, one or more input / output interfaces, and various connections (e.g., system buses) for connecting components.

[0026] For example, relative terms such as “about,” “approximately,” and “substantially,” used in relation to quantity or state, are understood by those skilled in the art to include the described value and have meanings indicated by the context (e.g., the term includes at least the degree of error related to measurement precision, tolerance [e.g., manufacturing, assembly, use, etc.], etc., related to a particular value). Such terms should also be considered as disclosing a range defined by the absolute values ​​of two endpoints. For example, the expression “about 2 to about 4” also discloses the range “2 to 4.” Relative terms may refer to ± a percentage of the indicated value (e.g., 1%, 5%, 10%).

[0027] While certain drawings illustrate hardware and software located within a particular device, it should be understood that these drawings are for illustrative purposes only. Functionality described herein as being performed by a single component may be performed by multiple components in a distributed manner. Similarly, functionality performed by multiple components may be integrated and performed by a single component. In some embodiments, the illustrated components may be combined or divided into separate software, firmware, and / or hardware. For example, logic and processing may be distributed across multiple electronic processors rather than being located within a single electronic processor and executed by a single electronic processor. Regardless of how they are combined or divided, hardware and software components may be located on the same computing device or distributed across different computing devices connected by one or more networks or other appropriate communication links. Similarly, a component described as performing a particular functionality may perform additional functionality not described herein. For example, a device or structure “configured” in a particular way may be configured in at least that way, but may also be configured in ways not explicitly enumerated.

[0028] Therefore, in a claim, if an apparatus, method, or system is claimed as including, for example, a controller, control unit, electronic processor, computing device, logic element, module, memory module, communication channel or network, or other elements configured in a particular way to perform a plurality of functions, for example, the claim or the invention specification shall be construed as meaning one or more of such elements if any one of the one or more elements is configured to perform any one or more of the recited plurality of functions such that the one or more elements perform the plurality of functions collectively as a set.

[0029] Other aspects of the embodiments will become apparent by considering the detailed description and the accompanying drawings.

Brief Description of the Drawings

[0030] [Figure 1] A perspective view of a power tool according to some embodiments is shown. [Figure 2] A block diagram of a control system of the power tool of FIG. 1 according to some embodiments is shown. [Figure 3] A battery pack for use with the power tool of FIG. 1 according to some embodiments is shown. [Figure 4] A block diagram of a control system of the battery pack of FIG. 3 according to some embodiments is shown. [Figure 5] An interior permanent magnet motor rotor according to some embodiments is shown. [Figure 6A] A diagram showing an interior permanent magnet motor according to some embodiments. [Figure 6B] A diagram showing an interior permanent magnet motor according to some embodiments. [Figure 6C] A diagram showing an interior permanent magnet motor according to some embodiments. [Figure 6D] A diagram showing an interior permanent magnet motor according to some embodiments. [Figure 7]Several embodiments of the resulting magnetic pole motor are shown. [Figure 8] The performance of various motors according to several embodiments is shown in the graph. [Figure 9] Several embodiments of the resulting magnetic pole motor are shown. [Figure 10] The performance of various motors according to several embodiments is shown in the graph. [Figure 11] Several embodiments of an internal permanent magnet motor are shown. [Figure 12] The performance of various motors according to several embodiments is shown in the graph. [Figure 13] Several embodiments of permanent magnet motors are shown. [Figure 14] Several embodiments of permanent magnet motors are shown. [Figure 15] Several embodiments of permanent magnet motors are shown. [Figure 16] The performance of various motors according to several embodiments is shown in the graph. [Figure 17] Several embodiments of permanent magnet motors are shown. [Modes for carrying out the invention]

[0031] Figure 1 shows a power tool 100 including a permanent magnet motor. The power tool 100 is, for example, a hammer drill including a housing 102. The housing 102 includes a handle portion 104 and a motor housing portion 106. The power tool 100 further includes an output driver 108 (shown 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. Although Figure 1 shows a hammer drill, in some embodiments the computing (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, and the like. In a permanent magnet motor power tool such as power tool 100, a switching element is selectively enabled and disabled by a control signal from the controller in order to selectively apply power from a power source (e.g., a battery pack) to drive the permanent magnet motor.

[0032] Figure 2 shows a control system 200 for a power tool 100. The control system 200 includes a controller 202. The controller 202 is electrically and / or communicatively connected to various 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 an FET switching module 220 (including, for example, multiple switching FETs), and a gate driver 224 for driving the FET switching module 220. In some embodiments, the motor 204 is a permanent magnet motor. The controller 202 includes, among other things, a combination of hardware and software that can be operated to control the operation of the power tool 100, monitor the operation of the power tool 100, and activate one or more indicators 214 (e.g., LEDs).

[0033] The controller 202 includes several electrical and electronic components that provide power, motion 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, microcontroller, electronic controller, electronic processor, or other suitable programmable device), memory 228, input unit 230, and output unit 232. The processing unit 226 includes, among other things, a control unit 234, an arithmetic logic unit ("ALU") 236, and several 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, memory 228, input unit 230, and output unit 232, as well as various modules or circuits connected to the controller 202, are connected by one or more control and / or data buses (e.g., a common bus 240). The control bus and / or data bus is generally shown in Figure 2 for illustrative purposes. The use of one or more control and / or data buses for interconnecting and communicating between various modules, circuits, and components will be known to those skilled in the art in view of the embodiments described herein.

[0034] Memory 228 is a non-temporary computer-readable medium and includes, for example, a program storage area and a data storage area. The program storage area and data storage area may include a combination of different types of memory, such as ROM, RAM (e.g., DRAM, SDRAM, etc.), EEPROM, flash memory, hard disk, SD card, or other suitable magnetic, optical, physical, or electronic memory devices. The processing unit 226 is connected to memory 228 and executes software instructions that can be stored (e.g., during execution) in the RAM of memory 228, (e.g., on a substantially permanent basis) in the ROM of memory 228, or in another non-temporary computer-readable medium such as another memory or disk. Software included in the implementation of the power tool 100 may 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 memory 228 and, among other things, execute instructions related to the control processes and methods described herein. In other configurations, the controller 202 may include additional components, fewer components, or different components.

[0035] 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 interface with (e.g., mechanically, electrically, and communicatively connect with) the battery pack and operable to interface with (e.g., mechanically, electrically, and communicatively connect with) the battery pack. For example, power supplied to the power tool 100 by the battery pack 300 (see Figure 3) is supplied to the power input module 218 through the battery pack interface 206. The power input module 218 includes a combination of active and passive components for adjusting or controlling the power received from the battery pack 300 before power is supplied to the controller 202. The battery pack interface 206 also supplies power to the FET switching module 220 so that it is switched by a switching FET to selectively supply power to the motor 204. The battery pack interface 206 also includes a communication line 242 for providing a communication line or link between the controller 202 and the battery pack 300.

[0036] The sensor circuit 212 includes one or more current sensors, one or more speed sensors, one or more Hall effect sensors, one or more temperature sensors, and so on. The indicator 214 includes, for example, one or more light-emitting diodes ("LEDs"). The indicator 214 may be configured to display the status of the power tool 100 or information related to the power tool. For example, the indicator 214 may be configured to show the measured electrical characteristics of the power tool 100, the status of the power tool, the status of the motor 204, and so on. The user input module 216 is operably coupled to the controller 202 to select, for example, a forward or reverse operating mode, torque and / or speed settings for the power tool 100 (for example, using torque and / or speed switches), and so on. 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, and so on.

[0037] Figure 3 shows the 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.

[0038] Figure 4 shows 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 various modules or components of the battery pack 300. For example, the illustrated controller 400 is connected to one or more battery cells 402 and interface 404 (e.g., interface portion 304 of the battery pack 300 illustrated in Figure 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, among other things, a combination of hardware and software that can control the operation of the battery pack 300, monitor the status of the battery pack 300, enable or disable charging of the battery pack 300, enable or disable discharging of the battery pack 300, and so on.

[0039] The controller 400 includes several 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, microcontroller, electronic processor, electronic controller, or another suitable programmable device), a memory 414, an input unit 416, and an output unit 418. The processing unit 412 includes, among other things, a control unit 420, an ALU 422, and several 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 unit 416, and the output unit 418, as well as various modules or circuits connected to the controller 400, are connected by one or more control and / or data buses (e.g., a common bus 426). The control bus and / or data bus is generally shown in Figure 4 for illustrative purposes. The use of one or more control and / or data buses for interconnecting and communicating between various modules, circuits, and components will be known to those skilled in the art in view of the embodiments described herein.

[0040] Memory 414 is a non-temporary computer-readable medium and includes, for example, a program storage area and a data storage area. The program storage area and data storage area may include a combination of different types of memory, such as ROM, RAM (e.g., DRAM, SDRAM, etc.), EEPROM, flash memory, hard disk, SD card, or other suitable magnetic, optical, physical, or electronic memory devices. Processing unit 412 is connected to memory 414 and executes software instructions that can be stored (e.g., during execution) in the RAM of memory 414, (e.g., on a nearly permanent basis) in the ROM of memory 414, or in another non-temporary computer-readable medium such as another memory or disk. Software included in the implementation of battery pack 300 may be stored in memory 414 of 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. Controller 400 is configured to retrieve from memory 414 and, among other things, execute instructions related to the control processes and methods described herein. In other configurations, the controller 400 may include additional components, fewer components, or different components.

[0041] 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 interface (e.g., mechanically, electrically, and communicatively connect) the battery pack 300 with other devices (e.g., power tools, battery pack chargers, etc.) and operable to interface (e.g., mechanically, electrically, and communicatively connect) the battery pack 300 with other devices (e.g., power tools, battery pack chargers, etc.). For example, interface 404 is configured to communicate with controller 400 via communication line 428.

[0042] Figure 5 shows an internal permanent magnet motor rotor 500 according to several embodiments. The rotor 500 includes a laminated stack 505. The laminated stack 505 includes an inner laminated portion 510 and an outer laminated portion 515. The rotor 500 includes a plurality of slots 520, each slot including a magnet housing portion 525 configured to receive a magnet 530. The magnet 530 includes a length 535 and a width 540. The rotor 500 also includes a rotor sleeve 545. In some embodiments, the rotor sleeve 545 is made of carbon fiber material. In some embodiments, the carbon fiber sleeve is made of a different material, such as plastic, a non-magnetic metal, or polycarbonate. The rotor 500 is configured to rotate relative to a stator.

[0043] Figures 6A to 6D show internal permanent magnet motor rotors 600A, 600B, 600C, and 600D according to several embodiments. As shown in Figure 6A, rotor 600A includes a laminate stack 605. The laminate stack 605 includes an inner laminate portion 610 and an outer laminate portion 615. Rotor 600A includes a plurality of slots 620, each slot 620 including a magnet housing portion 625 configured to receive a magnet 630. The magnet 630 includes a length 635 and a width 640. The inner laminate portion 610 of the laminate stack 605 includes a first axial support portion 645. The outer laminate portion 615 of the laminate stack 605 includes a second axial support portion 650. In some embodiments, a plastic mold 655 is configured to hold the inner laminate portion 610 and the outer laminate portion 615 of the laminate stack 605. The plastic mold 655 may include a first retaining portion 660 configured to hold the plastic mold 655 in the inner laminate portion 610, and a second retaining portion 665 configured to hold the plastic mold in the outer laminate portion 615. The plastic mold 655 also includes a plate 670 configured to connect the first retaining portion 660 and the second retaining portion 665 to each other, thereby creating a single fixed element for holding the inner laminate portion 610, the outer laminate portion 615, and the magnet 630. The rotor 600A is configured to rotate relative to the stator.

[0044] Figure 6B shows a permanent magnet motor rotor 600B. In this embodiment, the rotor 600B includes a first axial support portion 645, a first retaining portion 660, a second retaining portion 665, an injection-molded plastic plate 670, a second axial support portion 650, and a stainless steel plate portion 675. The stainless steel plate portion 675 is configured to connect to the second axial support portion 650. The rotor 600B is configured to rotate relative to the stator.

[0045] Figure 6C shows another embodiment of the rotor 600C. In this embodiment, both the first axial support portion 645 and the second axial support portion 650 are made of stainless steel and are configured to connect to the stainless steel plate portion 675. The rotor 600C is configured to rotate relative to the stator.

[0046] Figure 6D shows another embodiment of the rotor 600D. In this embodiment, an inner adhesive layer 680 and an outer adhesive layer 685 are used to hold the magnet 630 and the laminate stack 605 together. The adhesive used in the inner and outer adhesive layers (680, 685) may be epoxy, structural acrylic, cyanoacrylate, or other types of bonding material. In some cases, a Teflon® mold may be used during the assembly process. The rotor 600D is configured to rotate relative to the stator.

[0047] Figure 7 shows the resulting pole motor 700 according to several embodiments. The motor 700 includes a stator 705 and a plurality of stator winding slots 710. The stator also includes stator teeth 713. The plurality of stator winding slots 710 are configured to receive a plurality of windings wound around the stator teeth 713. The motor 700 also includes a rotor 715. The rotor 715 includes a plurality of permanent magnet slots 720 configured to receive permanent magnets 725. The rotor 715 includes a plurality of resulting poles 730. The resulting poles 730 have a length 735 and a width 740. In some embodiments, each of the resulting poles has the same length and width. In other embodiments, the resulting poles have different lengths and widths. In some embodiments, the length 735 or width 740 of the resulting poles 730 is controlled to affect the performance of the motor 700. The effect of the resulting dimensions of the magnetic pole 730 is shown in Figure 8 and will be described in detail below. The motor 700 includes an air gap 745 between the multiple permanent magnets 725 and the subsequent magnetic pole 730. In some embodiments, the air gap 745 is surrounded by outer ribs 750 of the laminate stack 755. In some embodiments, the air gap 745 is ribless. In some embodiments, the resulting magnetic pole 730 is made of a non-magnetic material (e.g., rotor laminate). In some embodiments, the resulting magnetic pole motor 700 may include any of the motor-rotor configurations described above with respect to Figures 5, 6A, 6B, 6C and 6D. The rotor 715 is configured to rotate relative to the stator.

[0048] Figure 8 graphs the performance of an internal permanent magnet ("IPM") motor compared to the resulting pole motor 700 in several embodiments. The graph includes IPM motor efficiency 805, IPM motor output power 815, IPM motor current 825, and IPM motor speed 835 compared to motor torque. The graph also includes the resulting pole motor efficiency 810, the resulting pole motor output power 820, the resulting pole motor current 830, and the resulting pole motor speed 840 compared to motor torque. Graph 800 also includes the highlighted operating region 845, in which both the IPM motor and motor 700 nominally operate. As demonstrated by Graph 800, the performance of both the IPM motor and motor 700 is similar within the operating region 845. In some cases, the IPM motor shown on graph 800 has a magnet mass of approximately 55g, while motor 700 has a mass reduction of approximately 28% without significantly affecting the performance of motor 700 within the operating range 845.

[0049] Figure 9 shows a resulting pole motor 900 according to several embodiments. The motor 900 includes a stator 905 and a plurality of stator winding slots 910. The stator also includes stator teeth 913. The plurality of stator winding slots 910 are configured to receive a plurality of windings wound around the stator teeth 913. The stator 905 includes air gaps 914 between the plurality of stator winding slots 910. The motor 900 also includes a rotor 915. The rotor 915 includes a plurality of permanent magnet slots 920 configured to receive permanent magnets 925. The rotor 915 includes a plurality of resulting poles 930. The resulting poles 930 have a length 935 and a width 940. In some embodiments, each of the resulting poles has the same length and width. In other embodiments, the resulting poles have different lengths and widths. In some embodiments, the length 935 or width 940 of the resulting magnetic pole 930 is controlled to affect the performance of the motor 900. The effect of the dimensions of the resulting magnetic pole 930 is shown in Figure 10 and described in detail below. The motor 900 also includes a gap 945 between the multiple magnets 925 and the resulting magnetic pole 930. In some embodiments, the gap 945 is surrounded by outer ribs 950 of the laminate stack 955. In some embodiments, the gap 945 is ribless. In some embodiments, the resulting magnetic pole 930 is made of a non-magnetic material (e.g., rotor laminate). In some embodiments, the resulting magnetic pole motor 900 may include any of the motor-rotor configurations described above with respect to Figures 5, 6A, 6B, 6C, and 6D. The rotor 915 is configured to rotate relative to the stator.

[0050] Figure 10 provides a graph 1000 showing a performance comparison between the internal permanent magnet motor and motor 900. The graph includes IPM motor efficiency 1005, IPM motor output power 1015, IPM motor current 1025, and IPM motor speed 1035, compared to motor torque. The graph also includes the resulting pole motor efficiency 1010, the resulting pole motor output power 1020, the resulting pole motor current 1030, and the resulting pole motor speed 1040, compared to motor torque. Graph 1000 also includes a target operating load 1045 of approximately 0.19 Nm and a target operating speed 1050 of approximately 42,000 RPM. As demonstrated by graph 1000, at higher torque levels, the IPM motor operates with greater efficiency 1005 and output power 1015 than the efficiency 1010 and output power 1020 of motor 900. However, the performance of both the IPM motor and motor 900 is similar within the target operating load range of 1045. In some cases, the IPM motor shown on graph 1000 has a magnet mass of approximately 79g, while motor 900 has a mass reduction of approximately 36% without significantly affecting the performance of motor 900 within the target operating load range of 1045.

[0051] Figure 11 shows an internal permanent magnet motor 1100 according to several embodiments. The motor 1100 includes a stator 1105 and a plurality of stator winding slots 1110. The stator 1105 also includes stator teeth 1113. The plurality of stator winding slots 1110 are configured to receive a plurality of windings wound around the stator teeth 1113. The motor 1100 also includes a rotor 1115. The rotor 1115 includes a plurality of slots 1120, each slot 1120 including a magnet housing portion 1125 configured to receive a magnet 1130. The magnet 1130 includes a length 1135 and a width 1140. The rotor 1115 further includes a laminate stack 1145, which includes an inner laminate portion 1150 and an outer laminate portion 1155. The inner laminate portion 1150 of the laminate stack 1145 includes a first axial support portion 1160. The outer laminate portion 1155 of the laminate stack 1145 includes a second axial support portion 1165. In some embodiments, the plastic mold is configured to hold the inner and outer laminate portions as described above and as shown in Figures 6A to 6D. The motor 1100 does not otherwise include outer steel ribs surrounding the magnet 1130.

[0052] Figure 12 is Graph 1200, which shows a performance comparison between a conventional internal permanent magnet motor and motor 1100. Graph 1200 includes conventional IPM motor efficiency 1205, conventional IPM motor output power 1215, conventional IPM motor current 1225, and conventional IPM motor speed 1235, compared to motor torque. Graph 1200 also includes motor efficiency 1210, output power 1220, motor current 1230, and motor speed 1240 for motor 1100, compared to motor torque. As demonstrated by Graph 1200, the conventional IPM motor operates with an efficiency 1205 that is almost the same as the efficiency 1210 of motor 1100. However, motor 1100 generates about 5% more power than, for example, the conventional IPM motor.

[0053] Figure 13 shows a permanent magnet motor according to several embodiments. In some embodiments, the motor 1300 is configured for use in a power tool 100. The motor 1300 includes an internal permanent magnet configuration. The motor 1300 includes a stator 1305 and a plurality of stator winding slots 1310. The plurality of stator winding slots 1310 are configured to receive a plurality of windings. The motor 1300 also includes a rotor 1315. In some embodiments, the rotor has an outer diameter of 22 millimeters ("mm"). The rotor 1315 includes a plurality of slots 1320, each slot including a magnet housing portion 1325 configured to receive a magnet 1330. The magnet 1330 includes a length 1335 and a width 1340. The rotor 1315 further includes a laminate stack 1345 and a gap 1350. The gap 1350 includes a length 1355 and a width 1360. In some embodiments, the size of the gap 1350, or the length 1355 and width 1360 of the gap 1350, increases or decreases in conjunction with the size of the magnet 1330. For example, the length 1335 of the magnet 1330 may be shortened to reduce the manufacturing cost of the motor 1300. Accordingly, the length 1355 of the gap may increase in conjunction with the reduced size of the magnet 1330. Alternatively, in some embodiments, the laminated stack 1345 is configured to occupy the space of the reduced length 1335 of the magnet 1330.

[0054] Figure 14 shows a permanent magnet motor according to several embodiments. The motor 1400 includes a stator 1405 and a plurality of stator winding slots 1410. The stator also includes stator teeth 1413. The plurality of stator winding slots 1410 are configured to receive a plurality of windings wound around the stator teeth 1413. The motor 1400 also includes a rotor 1415. The rotor 1415 includes a plurality of slots 1420, each slot including a magnet housing portion 1425 configured to receive a magnet 1430. The magnet 1430 includes a length 1435 and a width 1440. The rotor further includes a laminate stack 1445, which includes an inner laminate portion 1450 and an outer laminate portion 1455. The inner laminate portion 1450 of the laminate stack 1445 includes a first axial support portion 1460. In some embodiments, the motor 1400 is similar to the motor 1100.

[0055] Figure 15 shows an internal permanent magnet motor according to several embodiments. The motor 1500 includes a stator 1505 and a plurality of stator winding slots 1510. The stator also includes stator teeth 1513. The plurality of stator winding slots 1510 are configured to receive a plurality of windings wound around the stator teeth 1513. The motor 1500 also includes a rotor 1515. The rotor 1515 includes a plurality of slots 1520, each slot including a magnet housing portion 1525 configured to receive a magnet 1530. The magnet 1530 includes a length 1535 and a width 1540. The rotor further includes a laminate stack 1545, which includes an inner laminate portion 1550 and an outer laminate portion 1555. The inner laminate portion 1550 of the laminate stack 1545 includes a first axial support portion 1560. The outer laminate portion 1555 of the laminate stack 1545 includes a second axial support portion 1565. In some embodiments, the plastic mold is configured to hold the inner and outer laminate portions as described above and as shown in Figures 6A to 6D.

[0056] Figure 16 provides Graph 1600, which shows a performance comparison between motors 1300, 1400, and 1500. The graph includes the efficiency 1605, output power 1620, current 1635, and speed 1650 of motor 1300 compared to motor torque. The graph includes the efficiency 1610, output power 1625, current 1640, and speed 1655 of motor 1400 compared to motor torque. The graph includes the efficiency 1615, output power 1630, current 1645, and speed 1660 of motor 1500 compared to motor torque. Graph 1600 also includes a target operating range 1665, which spans motor torques of approximately 0.5 Nm to 3.9 Nm. As demonstrated by Graph 1600, at higher torque levels, motor 1400 operates with a greater efficiency of 1610 and output power of 1625 than motor 1300 (efficiency 1605 and output power 1620) and motor 1500 (efficiency 1615 and output power 1630). Table 1 further shows a comparison between motors 1300, 1400, and 1500. Motor 1400 operates with nearly the same efficiency and magnet mass as motor 1300, while having 6% more watt-newton meters (WNm) and 7% more peak power (W). On the other hand, motor 1500 achieves more than 1% more WNm with less than 1% lower peak power, while having a 35% reduction in magnet mass. [Table 1]

[0057] Figure 17 shows a rotor assembly 1700 for use with a power tool 100. The rotor assembly 1700 includes a plurality of slots 1705, each slot 1705 configured to receive a magnet 1710. The magnet 1710 may be made of a rare earth metal such as neodymium, as previously mentioned, and can be fixed in the slot 1705. The rotor assembly 1700 includes a laminated stack 1715 with a plurality of gaps 1720. In some examples, the gaps 1720 are filled with injection-molded plastic 1725 or an injection-molded material such as stainless steel. The rotor assembly 1700 also includes a shaft 1730 extending through the rotor assembly 1700 from a first end 1735 to a second end 1740. A first bearing 1745 is located at the first end 1735 of the rotor assembly 1700 together with a sensing magnet 1750. The rotor assembly 1700 also includes a fan 1755 located at the second end 1740 of the rotor assembly 1700. The rotor assembly 1700 further includes a second bearing 1760 located at the second end 1740 of the rotor assembly 1700, and a plurality of C-rings 1765 configured to connect the second bearing 1760 to the shaft 1730.

[0058] Therefore, the embodiments described herein provide a power tool including a resulting magnetic pole motor. Various configurations and advantages are described in the following claims.

Claims

1. A power tool comprising a battery pack interface configured to receive a battery pack, and a motor, The aforementioned motor is A stator including multiple stator teeth configured to receive multiple stator windings, A rotor configured to rotate relative to the stator, A laminated stack including an inner laminated portion and an outer laminated portion, A first permanent magnet in the rotor within a first slot of the laminated stack, wherein the first slot is located between the inner laminated portion and the outer laminated portion, A second permanent magnet in the rotor within a second slot of the laminated stack, wherein the second slot is located between the inner laminated portion and the outer laminated portion, The resulting magnetic pole is located between the first permanent magnet and the second permanent magnet, has a length and width, and is made of a non-magnetic material, The rotor and, Including a mold located between the inner laminate portion and the outer laminate portion, Power tools.

2. The power tool according to claim 1, wherein the first permanent magnet and the second permanent magnet are made of rare earth metals.

3. The resulting magnetic pole is constructed from the laminated stack, as described in claim 1.

4. The power tool according to claim 1, wherein the inner laminate portion includes a first axial support portion, and the outer laminate portion includes a second axial support portion.

5. The power tool according to claim 1, wherein the rotor has an outer diameter of about 22 millimeters.

6. A power tool comprising a battery pack interface configured to receive a battery pack, and a resulting magnetic pole motor, The resulting magnetic pole motor is A stator including multiple stator teeth configured to receive multiple stator windings, A rotor configured to rotate relative to the stator, A laminated stack including an inner laminated portion and an outer laminated portion, The first permanent magnet in the first slot of the rotor, The second permanent magnet in the second slot of the rotor, A first resulting magnetic pole between the first permanent magnet and the second permanent magnet having a first length and a first width, A second resulting magnetic pole between the first permanent magnet and the second permanent magnet, having a second length and a second width, The rotor, including, The void is adjacent to the first resulting magnetic pole located between the first slot of the rotor and the inner and outer laminate portions, and the void is surrounded by the outer ribs of the laminate stack. Power tools.

7. The power tool according to claim 6, wherein the first permanent magnet and the second permanent magnet are made of rare earth metals.

8. The power tool according to claim 6, wherein the magnetic poles obtained as a result of the first and second processes are constructed from the laminated stack.

9. The power tool according to claim 6, wherein the inner laminate portion includes a first axial support portion, and the outer laminate portion includes a second axial support portion.

10. The rotor is Stacked structures, A first slot including a first magnet housing portion configured to receive the first permanent magnet, A second slot including a second magnet housing portion configured to receive the second permanent magnet, It further includes a plurality of voids, and each of the plurality of voids contains an injection molding material. One of the aforementioned multiple voids is surrounded by the outer rib of the laminate stack. The power tool according to claim 6.

11. A stator including multiple stator teeth configured to receive multiple stator windings, A rotor configured to rotate relative to the stator, wherein the rotor is A laminated stack including an inner laminated portion and an outer laminated portion, A first permanent magnet located in a first slot of the laminated stack, wherein the first slot is located between the inner laminated portion and the outer laminated portion, A second permanent magnet located in a second slot of the laminated stack, wherein the second slot is located between the inner laminated portion and the outer laminated portion, A first resulting magnetic pole located between the first permanent magnet and the second permanent magnet, having a first length and a first width, A second resulting magnetic pole located between the first permanent magnet and the second permanent magnet, having a second length and a second width, A mold located between the inner laminate portion and the outer laminate portion, The resulting magnetic pole motor.

12. The resulting magnetic pole motor according to claim 11, wherein the first resulting magnetic pole and the second resulting magnetic pole are constructed from the laminated stack.

13. The first permanent magnet and the second permanent magnet are composed of rare earth metals. The first resulting magnetic pole and the second resulting magnetic pole are constructed from a non-magnetic material. A magnetic pole motor obtained as a result of claim 11.

14. The resulting magnetic pole motor according to claim 11, wherein the mold is surrounded by the outer ribs of the laminate stack.

15. The resulting magnetic pole motor according to claim 11, wherein the mold is filled with injection molding material.

16. The rotor further includes a first retaining portion configured to hold the inner laminate portion and a second retaining portion configured to hold the outer laminate portion, The first retaining portion and the second retaining portion are connected via a plate. A magnetic pole motor obtained as a result of claim 11.

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