Drive unit

Abstract

A drive unit for a power tool includes a motor and a blower assembly. The motor includes a rotor shaft, a stator, and a rotor. The rotor shaft extends along an axis of rotation. The stator is mounted to the rotor shaft. The rotor at least partially surrounds the stator. The rotor has a rotor core, a plurality of magnets, and an overmolded housing coupling the plurality of magnets to the rotor core to form a pole having more than one magnet per pole. The blower assembly includes a plurality of blower fan blades. The blower assembly is configured to be driven by a motor.

Description

Technical Field

[0001] The embodiments described herein relate to a motor for a power tool. Background Art

[0002] The drive units of power tools in the prior art have disadvantages such as short life, high noise, high vibration, and low aerodynamic efficiency. Utility Model Content

[0003] The drive unit of the power tool described herein includes a motor and a blower assembly. The motor includes a rotor shaft, a stator, and a rotor. The rotor shaft extends along an axis of rotation. The stator is mounted to the rotor shaft. The rotor at least partially surrounds the stator. The rotor has a rotor core, a plurality of magnets, and an overmolded housing that couples the plurality of magnets to the rotor core to form a pole with a plurality of magnets per pole. The blower assembly includes a plurality of blower fan blades. The blower assembly is configured to be driven by the motor.

[0004] The drive unit of a power tool described herein includes a motor and a blower assembly. The motor includes a rotor shaft, a stator, and a rotor. The rotor shaft extends along a rotational axis. The stator is mounted to the rotor shaft. The rotor at least partially surrounds the stator. The rotor is configured to be driven by the stator. The rotor is coupled to the rotor shaft to drive the rotor shaft to rotate about the rotational axis. The blower assembly includes a plurality of blower fan blades extending radially outward from an outer surface of the motor.

[0005] The method for manufacturing a drive unit for a power tool described herein includes providing a rotor shaft and a stator mounted to the rotor shaft, forming a rotor core, positioning the stator within the rotor core after the rotor core is formed, attaching the rotor core to the rotor shaft, and attaching a blower assembly to one of the rotor shaft and the rotor core.

[0006] Before any embodiments are explained in detail, it is to be understood that the embodiments are not limited to the details of construction and arrangement of components set forth in the following description or shown in the accompanying drawings. The embodiments can be practiced or implemented in various ways. In addition, it is to be understood that the words and terms used herein are for descriptive purposes and should not be considered limiting. The use of "including," "comprising," or "having" and variations thereof are intended to encompass the items listed thereafter and their equivalents as well as additional items. Unless otherwise specified or limited, the terms "mounted," "connected," "supported," and "coupled," and variations thereof, are used broadly and encompass both direct and indirect mounting, connection, support, and coupling.

[0007] The articles "a" and "the" should not be construed as meaning "one" or "only one" unless the context clearly indicates otherwise. Instead, these articles should be construed as meaning "at least one" or "one or more." Similarly, when the terms "the" or "the" are used to refer to a noun preceded by the indefinite article "a," "the" and "the" mean "at least one" or "one or more" unless the context clearly indicates otherwise.

[0008] In addition, it should be understood that the embodiments may include hardware, software, and electronic components or modules, and for ease of discussion, they may be shown and described as if most components are implemented only in hardware. However, those of ordinary skill in the art will recognize, based on a reading of this detailed description, that in at least one embodiment, the electronic-based aspects may be implemented in software (e.g., stored on a non-transitory computer-readable medium) that can be executed by one or more processing units (e.g., microprocessors and / or application-specific integrated circuits (“ASICs”)). Therefore, it should be noted that the embodiments may be implemented using multiple hardware- and software-based devices and multiple different structural components. For example, the “server,” “computing device,” “controller,” “processor,” etc. described in the specification may include one or more processing units, one or more computer-readable media modules, one or more input / output interfaces, and various connections (e.g., a system bus) connecting components.

[0009] Relative terms used in conjunction with quantities or conditions, such as, for example, "about," "approximately," "substantially," etc., will be understood by those of ordinary skill in the art to include the stated value and have the meaning dictated by the context (e.g., the terms include at least the degree of error associated with measurement precision, the tolerance associated with the particular value [e.g., manufacturing, assembly, use, etc.], etc.). Such terms should also be considered to disclose a range defined by the absolute values ​​of the two endpoints. For example, the expression "from about 2 to about 4" also discloses a range of "from 2 to 4." Relative terms can refer to a positive or negative percentage (e.g., 1%, 5%, 10%) of the indicated value.

[0010] It should be understood that although some of the figures show hardware and software located within specific devices, these depictions are for illustrative purposes only. Functions described herein as being performed by one component can be performed by multiple components in a distributed manner. Similarly, functions performed by multiple components can be combined and performed by a single component. In some embodiments, the components shown can be combined or divided into separate software, firmware and / or hardware. For example, logic and processing can be distributed between multiple electronic processors rather than being located within and performed by a single electronic processor. Regardless of how they are combined or divided, hardware and software components can be located on the same computing device, or can be distributed between different computing devices connected by one or more networks or other suitable communication links. Similarly, components described as performing specific functions can also perform additional functions not described herein. For example, a device or structure that is "constructed" in a certain way is constructed at least in that way, but can also be constructed in a way that is not explicitly listed.

[0011] Thus, in the claims, if a device, method, or system is claimed that includes, for example, a controller, a control unit, an electronic processor, a computing device, a logic element, a module, a memory module, a communication channel or network, or other elements constructed in some manner, for example, to perform multiple functions, then the claim or claim element should be interpreted as meaning one or more such elements, where any one of the one or more elements is constructed in accordance with the claim, for example, to perform any one or more of the multiple functions, such that the one or more elements as a collection collectively perform the multiple functions.

[0012] Other aspects of the embodiments will become apparent by consideration of the detailed description and accompanying drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0013] Figure 1 A side view of a power tool is shown, according to some embodiments.

[0014] Figure 2 According to some embodiments Figure 1 Block diagram of the control system of a power tool.

[0015] Figure 3 shows a method for communicating with Figure 1 A battery pack for use with a power tool.

[0016] Figure 4 According to some embodiments Figure 3 Block diagram of the battery pack control system.

[0017] Figure 5 A drive unit including a motor and blower assembly is shown according to some embodiments.

[0018] Figure 6 According to some embodiments Figure 5 Schematic diagram of the motor.

[0019] Figure 7A According to some embodiments Figure 6 Schematic diagram of the motor lamination.

[0020] Figure 7B According to some embodiments Figure 6 Another schematic diagram of the motor laminations.

[0021] Figure 8 According to some embodiments Figure 6 Schematic diagram of the motor's rotor core and magnets.

[0022] Figure 9 According to some embodiments Figure 5 Cross-sectional view of the rotor shaft, rotor, magnets and motor fan of the drive unit.

[0023] Figure 10 According to some embodiments Figure 5 A method for manufacturing a drive unit.

[0024] Figure 11 A drive unit including a motor and blower assembly is shown according to some embodiments.

[0025] Figure 12 According to some embodiments Figure 11 A perspective view of the rotor core, magnets, and housing of a motor.

[0026] Figure 13 According to some embodiments Figure 11 Schematic diagram of the motor's rotor core, magnets, and housing.

[0027] Figure 14 According to some embodiments Figure 11 A method for manufacturing a drive unit.

[0028] Figure 15 A motor fan according to some embodiments is shown.

[0029] Figure 16 An end cap of a motor is shown, according to some embodiments.

[0030] Figure 17 A rotor core and magnets are shown according to some embodiments.

[0031] Figure 18 is a graphical representation of efficiency, current, and speed operating curves for various motors, according to some embodiments.

[0032] Figure 19 A motor implemented within a power tool is shown, according to some embodiments. DETAILED DESCRIPTION

[0033] Figure 1 A power tool 100 is shown that includes a drive unit having an outer rotor motor. The power tool 100 is, for example, a hammer drill that includes a housing 102. In other embodiments, the power tool 100 can be any other type of power tool that includes a motor, such as a blower. The housing 102 includes a handle portion 104 and a motor housing portion 106. The power tool 100 also includes an output drive 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 a power tool battery pack or to receive a power tool battery pack. Although Figure 1 A hammer drill is shown, and in some embodiments, the components described herein are incorporated into other types of power tools, including drill drivers, impact drivers, impact wrenches, sanders, angle grinders, circular saws, reciprocating saws, plate compactors, core drills, corded mowers, blowers, vacuum cleaners, etc. In an outrunner motor power tool (such as power tool 100), a switching element is selectively enabled and disabled by a control signal from a controller to selectively apply power from a power source (e.g., a battery pack) to drive the outrunner motor.

[0034] Figure 2 A control system 200 for a power tool 100 is shown. The control system 200 includes a controller 202. The controller 202 is electrically connected and / or communicatively coupled to various modules or components of the power tool 100. For example, the 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 switch module 220 (e.g., including a plurality of switching FETs), and a gate driver 224 for driving the FET switch module 220. In some embodiments, the motor 204 is an outer rotor motor. The controller 202 includes a combination of hardware and software that is operable to, among other things, control the operation of the power tool 100, monitor the operation of the power tool 100, activate one or more indicators 214 (e.g., LEDs), and the like.

[0035] The controller 202 includes a plurality of electrical and electronic components that provide power, operational control, and protection for the controller 202 and / or components and modules within 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, an input unit 230, and an output unit 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 known computer architectures (e.g., a modified Harvard architecture, a von Neumann architecture, etc.). The processing unit 226, the memory 228, the input unit 230, the output unit 232, and the various modules or circuits connected to the controller 202 are connected via one or more control and / or data buses (e.g., a common bus 240). Figure 2 The control and / or data buses are generally shown in the figure for illustration purposes. In view of the invention described herein, those skilled in the art will appreciate that one or more control and / or data buses are used to achieve interconnection and communication between various modules, circuits and components.

[0036] 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 may include a combination of different types of memory, such as ROM, RAM (e.g., DRAM, SDRAM, etc.), EEPROM, flash memory, a hard drive, an SD card, or other suitable magnetic, optical, physical, or electronic storage devices. The processing unit 226 is connected to the memory 228 and executes software instructions, which may be stored in the RAM of the memory 228 (e.g., during execution), in the ROM of the memory 228 (e.g., in a substantially permanent manner), or in another non-transitory computer-readable medium (e.g., another memory or disk). The software included in the implementation of the power tool 100 may be stored in the memory 228 of the controller 400. This software includes, for example, firmware, one or more application programs, program data, filters, rules, one or more program modules, and other executable instructions. The controller 202 is configured to retrieve and execute instructions from the memory 228, among other things, related to the control processes and methods described herein. In other configurations, the controller 202 includes more, fewer, or different components.

[0037] 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) that are configured and operable to interface (e.g., mechanically, electrically, and communicate) with the battery pack. For example, the battery pack 300 (see Figure 3) The power provided to the power tool 100 is provided 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 conditioning or controlling the power received from the battery pack 300 before the power is provided to the controller 202. The battery pack interface 206 also provides power to the FET switch module 220 for switching by the switch FET 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.

[0038] The sensors 212 include one or more current sensors, one or more speed sensors, one or more Hall effect sensors, one or more temperature sensors, and the like. The indicator 214 includes, for example, one or more light emitting diodes ("LEDs"). The indicator 214 can be configured to display the status of the power tool 100 or information related to the power tool 100. For example, the indicator 214 is configured to indicate a measured electrical characteristic of the power tool 100, the status of the power tool, the status of the motor 204, and the like. The user input module 216 can be operably coupled to the controller 202, for example, to select a forward operating mode or a reverse operating mode, a torque and / or speed setting for the power tool 100 (e.g., using a torque and / or speed switch), and the like. In some embodiments, the user input module 216 includes a combination of digital and analog input or output devices required to achieve the desired level of operation of the power tool 100, such as one or more knobs, one or more dials, one or more switches, one or more buttons, and the like.

[0039] Figure 3 A battery pack 300 is shown. The battery pack 300 includes a housing 302 and an interface portion 304 for connecting the battery pack 300 to a power tool (eg, power tool 100).

[0040] Figure 4 The control system of the battery pack 300 is shown. 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 controller 400 is shown connected to one or more battery cells 402 and an interface 404 (e.g., 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 comprises a combination of hardware and software operable to, among other things, 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 the like.

[0041] The controller 400 includes a plurality of electrical and electronic components that provide power, operational control, and protection for 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, 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 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 unit 416, and the output unit 418, as well as the various modules or circuits connected to the controller 400, are connected via one or more control and / or data buses (e.g., a common bus 426). For illustrative purposes, Figure 4 A control and / or data bus is generally shown in FIG. In view of the invention described herein, one skilled in the art will appreciate the use of one or more control and / or data buses to achieve interconnection and communication between various modules, circuits, and components.

[0042] 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 may include a combination of different types of memory, such as ROM, RAM (e.g., DRAM, SDRAM, etc.), EEPROM, flash memory, a hard drive, an SD card, or other suitable magnetic, optical, physical, or electronic storage devices. The processing unit 412 is connected to the memory 414 and executes software instructions, which can be stored in the RAM of the memory 414 (e.g., during execution), in the ROM of the memory 414 (e.g., in a substantially permanent manner), or in another non-transitory computer-readable medium (e.g., another memory or disk). The software included in the implementation of the battery pack 300 may be stored in the memory 414 of the controller 400. The software includes, for example, firmware, one or more application programs, program data, filters, rules, one or more program modules, and other executable instructions. The controller 400 is configured to retrieve and execute, among other things, instructions related to the control processes and methods described herein, from the memory 414. In other configurations, the controller 400 includes more, fewer, or different components.

[0043] The interface 404 includes a combination of mechanical components (e.g., rails, grooves, latches, etc.) and electrical components (e.g., one or more terminals) that are configured and operable to interface (e.g., mechanically, electrically, and communicatively connect) 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 be communicatively connected to the controller 400 via a communication line 428.

[0044] Figure 5 A drive unit 510 is shown in accordance with an embodiment of the present disclosure. The drive unit 510 includes a motor assembly or motor 514 and a blower assembly 518. The motor 514 is a brushless direct current ("BLDC") outer rotor motor and is configured to respond to user input (e.g., a trigger (e.g., Figure 1 Actuation of the trigger 110) in a controller (e.g., Figure 2 The motor 514 is configured to drive a power tool (e.g., Figure 1 The blower assembly 518 is coupled to the motor 514 so that the motor 514 drives the rotation of the blower assembly 518. The blower assembly 518 can be configured to direct airflow out of the power tool (e.g., blow it out). The blower assembly 518 can also be configured to draw airflow into (e.g., vacuum it into) the power tool. In addition, the airflow caused by the blower assembly 518 can be used to cool internal components of the power tool, such as the motor 514.

[0045] refer to Figure 5 and 6 , the motor 514 includes a rotor shaft 522, a stator 526, a rotor 530 and a motor fan 534. The motor 514 is an outer rotor motor such that the stator 526 is at least partially surrounded by the rotor 530. The rotor shaft 522 extends along the motor axis A1 and is configured to rotate about the motor axis A1. The rotor shaft 522 can be engaged with a transmission device (not shown) of a power tool to drive a working operation. The stator 526 is mounted on the rotor shaft 522 and can be connected to the housing of the power tool (e.g., Figure 1 526 ). The rotor shaft 522 is supported by the housing 102 of the rotor 526 so that the rotor shaft 522 is configured to rotate relative to the stator 526. Therefore, the stator 526 can be mounted to the rotor shaft 522 via a bushing or bearing 538, which reduces friction between the stator 526 and the rotor shaft 522 to increase the ease with which the rotor shaft 522 can rotate relative to the stator 526. The stator 526 includes a plurality of windings (not shown) that can be energized under the control of the controller 202 to cause the rotor 530 to rotate. In the illustrated embodiment, the rotor 530 is mounted to the rotor shaft 522 via a motor-fan 534 so that the rotation of the rotor 530 drives the rotation of the rotor shaft 522 via the motor-fan 534.

[0046] The rotor 530 includes a rotor core 542 and a plurality of magnets 546 coupled to the rotor core 542. Figure 6 and Figure 7A, the rotor core 542 is formed by a plurality of laminations 550 that are fixed together to form a generally hollow cylinder. Thus, the stator 526 is located within the generally hollow cylinder formed by the laminations 550. The laminations 550 can be interlocked together to form the body of the rotor core 542. Specifically, the laminations 550 include protrusions 550a, and the protrusions 550a are configured to be inserted into gaps 550b formed by the protrusions 550a of adjacent laminations 550 to interlock the laminations 550 together. In some embodiments, as Figure 7B As shown, the laminations 550' can be glued together. That is, each lamination 550' can be directly glued to one or two adjacent laminations 550'. In this way, each lamination 550' can be positioned face to face with adjacent laminations 550'. In other embodiments, the rotor core 542 can be processed to form a machined core. That is, for example, the rotor core 542 can be die-cast to form a uniform body of the rotor core 542. In other embodiments, the rotor core 542 can be a powder metallurgy core. That is, the rotor core 542 can be formed by a powder metallurgy process, in which powdered metal is sintered together to form a uniform body of the rotor core 542.

[0047] refer to Figure 8 , magnets 546 are coupled to the rotor core 542 to form or create a plurality of rotor poles 554 on the rotor core 542. In the illustrated embodiment, the magnets 546 are glued to the inner circumferential surface 542a of the rotor core 542, and each of the plurality of rotor poles 554 includes a single magnet 546. The magnets 546 are arc-shaped so that the magnets 546 fit directly onto the inner circumferential surface 542a of the rotor core 542. That is, the magnets 546 may extend along an arc having the same curvature as the inner circumferential surface 542a of the rotor core 542. Figure 6 and 8 , with magnet 546 coupled to inner circumferential surface 542a of rotor core 542, magnet 546 faces stator 526 and is configured to be magnetically engaged by stator windings (not shown) to cause rotation of rotor 530. A motor having a single magnetic pole 554 can be advantageously used in power tools having applications in which high rotational speeds are required because the single magnetic pole 554 enables the motor 514 to rotate faster than a motor having multiple magnets. Therefore, the single magnetic pole 554 can be advantageously used in motors for power tools, such as blowers, sanders, grinders, and other similar tools, in which rotational speed can be prioritized over output torque.

[0048] like Figure 9As shown, the motor fan 534 can be press-fit or snap-fitted to the rear end of the rotor core 542 so that the motor fan 534 is coupled to rotate with the rotor core 542. In some embodiments, the motor fan 534 is integrally molded with the overmolding of the rotor 530. The motor fan 534 is also mounted to the rotor shaft 522. Therefore, when the rotor 530 rotates, the rotor 530 drives the motor fan 534 to rotate, which drives the rotor shaft 522 to rotate. The rotation of the motor fan 534 causes a cooling air flow that passes through the motor 514 to cool the rotor shaft 522, the stator 526 ( Figure 6 ), rotor 530 and controller 202.

[0049] In the illustrated embodiment, reference Figure 9 The motor fan 534 includes a hub 558, a plurality of fan blades 562, and a sidewall 566. The hub 558, the plurality of fan blades 562, and the sidewall 566 are all formed together by molding. The hub 558 includes a hole 570 for mounting the motor fan 534 on the rotor shaft 522. Therefore, the motor axis A1 extends through the center of the hole 570 and, thus, through the center of the hub 558. In the illustrated embodiment, the hub 558 is directly mounted on the rotor shaft 522 to drive the rotation of the rotor shaft 522. In other embodiments, the hub 558 may be mounted on the rotor shaft 522 using bearings or bushings. The fan blades 562 are evenly spaced around the hub 558 and extend between the hub 558 and the sidewall 566. Therefore, the fan blades 562 define air gaps 574 between adjacent fan blades 562 to allow cooling air to pass therethrough. The sidewalls 566 are press-fit onto the rotor core 542 to couple the motor fan 534 to the rotor core 542 for rotation therewith.

[0050] In the illustrated embodiment, the motor fan 534 is an axial flow fan, such that the motor fan 534 is configured to induce an axial flow of cooling air from behind the motor 514 and blow the air through the motor 514 to cool the rotor shaft 522, the stator 526, the rotor 530, and the controller 202. In other embodiments, the motor fan 534 can be a centrifugal fan, such that the motor fan 534 draws an axial flow of cooling air from the front of the motor 514 and directs the cooling airflow through the rotor shaft 522, the stator 526, the rotor 530, and the controller. Once the air reaches the motor fan 534, the motor fan 534 can exhaust the cooling air radially outward from the motor fan 534.

[0051] Reference again Figure 5The blower assembly 518 includes a blower fan 578 having a blower hub 582 and a plurality of blower fan blades 586. In the illustrated embodiment, the blower fan hub 582 is mounted to the rotor shaft 522 via a bushing 590 that is insert-molded directly into the blower fan hub 582. In other embodiments, the rotor shaft 522 may be knurled and pressed directly into the blower fan hub 582. The blower fan 578 is mounted on the rotor shaft 522 in front of the motor 514. However, the blower fan 578 may also be mounted on the rotor shaft 522 in rear of the motor 514. The blower fan blades 586 extend radially away from the blower fan hub 582. Furthermore, the blower fan blades 586 extend at an angle between the front of the blower fan hub 582 and the rear of the blower fan hub 582. That is, the blower fan blades 586 do not extend along the shortest path between the front side of the blower fan hub 582 and the back side of the blower fan hub 582. In the illustrated embodiment, the blower fan blades 586 are integrally formed with the blower fan hub 582. In other embodiments, the blower fan blades 586 can be formed separately and attached to the blower fan hub 582.

[0052] The blower assembly 518 also includes a locking ring 594 mounted to the rotor shaft 522, which locks the axial position of the blower fan 578 relative to the rotor shaft 522. Specifically, the locking ring 594 is fixed relative to the rotor shaft 522, such that the locking ring 594 prevents the blower assembly 518 from sliding along the rotor shaft 522. In some embodiments, the locking ring 594 may be integrally formed on the rotor shaft 522. In other embodiments, the locking ring 594 may be fixedly attached to the rotor shaft 522. In still other embodiments, the blower assembly 518 may include a locking ring 594 on each side of the blower fan 578. In other embodiments, the rotor shaft 522 may be threaded, and the blower assembly 518 may include a nut that is threaded onto the rotor shaft 522 to lock the axial position of the blower fan 578 relative to the rotor shaft 522. In such embodiments, by adjusting the position of the nut along the threads of the rotor shaft 522, the blower fan 578 may be adjustable along the rotor shaft 522.

[0053] Figure 10 Shows the manufacturing Figure 5 Although the steps of the method 600 are disclosed herein in a particular order, it should be understood that the steps do not need to be completed in the order disclosed herein unless otherwise specified.

[0054] refer to Figure 6 and 10At step 610, method 600 includes providing a rotor shaft 522 and a stator 526 mounted to the rotor shaft 522. Step 620 includes forming a rotor core 542. In the illustrated embodiment, referring to Figures 7A and 10, step 620 includes providing a plurality of laminations 550, forming a protrusion 550a in each lamination 550, and stacking the laminations 550 together such that the protrusion 550a of each lamination 550 extends into the gap 550b formed by the protrusion 550a of an adjacent lamination 550. In other embodiments, step 620 may include gluing the laminations 550 together in a face-to-face orientation such that a face of each lamination 550 is glued to a face of an adjacent lamination 550. In yet other embodiments, step 620 may include machining the rotor core 542 by, for example, die casting the rotor core 542. In yet other embodiments, step 620 may include forming the rotor core 542 by a powder metallurgy process, wherein powdered metal is sintered together to form the rotor core 542.

[0055] Once the main body of the rotor core 542 is formed, a plurality of magnets 546 may be attached to the inner circumferential surface 542a of the main body. Specifically, the magnets 546 may be glued to the inner circumferential surface 542a of the main body. In the illustrated embodiment, attaching the magnets 546 to the main body of the rotor core 542 forms magnetic poles 554 on the rotor core 542.

[0056] Step 630 includes positioning the stator 526 within the rotor core 542. Specifically, step 630 includes positioning the stator 526 so that the rotor core 542 surrounds at least a portion of the stator 526. Step 640 includes attaching the rotor core 542 to the rotor shaft 522. In the illustrated embodiment, step 640 includes attaching the motor fan 534 to the rotor core 542 with a press fit between the rear end of the rotor core 542 and the front end of the sidewall 566 of the motor fan 534, and mounting the hub 558 of the motor fan 534 to the rotor shaft 522. In some embodiments, step 640 may include attaching an end cap to the rotor core 542 and mounting the end cap to the rotor shaft 522.

[0057] Step 650 includes attaching the blower assembly 518 to the motor 514. In the illustrated embodiment, step 650 includes insert molding the bushing 590 onto the blower fan 578 and mounting the blower fan 578 onto the rotor shaft 522. Step 650 also includes mounting a locking ring 594 onto one of the rotor shaft 522 and the blower fan 578, such that the locking ring 594 engages a shoulder on the other of the rotor shaft 522 and the blower fan 578 to prevent the blower fan 578 from moving along the rotor shaft 522. In other embodiments, step 650 may include knurling the rotor shaft 522 and press-fitting the blower fan 578 onto the knurled portion of the rotor shaft 522. In still other embodiments, step 650 may include providing the rotor shaft 522 with a threaded portion and threading a nut onto the threaded portion to engage the blower fan 578 and prevent the blower fan 578 from sliding along the rotor shaft 522. Once the drive unit 510 is assembled, the method 600 may further include installing the drive unit 510 within a power tool.

[0058] Figure 11 A drive unit 710 is shown according to other embodiments of the present disclosure. The drive unit 710 includes a motor assembly or motor 714 and a blower assembly 718. The motor 714 is a brushless direct current ("BLDC") outer rotor motor and is configured to respond to user input (e.g., a trigger (e.g., Figure 1 Actuation of the trigger 110) in a controller (e.g., Figure 2 The motor 714 is configured to drive a power tool (e.g., Figure 1 The blower assembly 718 is coupled to the motor 714 so that the motor 714 drives the rotation of the blower assembly 718. The blower assembly 718 is configured to direct airflow out of the power tool (e.g., blow it out). The blower assembly 718 can also be configured to draw airflow into (e.g., vacuum it into) the power tool. In addition, the airflow caused by the blower assembly 718 can also be used to cool the internal components of the power tool.

[0059] In addition to the differences described herein, the motor 714 can be used with Figure 6 The motor 514 is basically the same. Therefore, the reference Figure 11 , the motor 714 is an outer rotor motor, including a rotor shaft 722, a stator (e.g., Figure 6The stator 526 is a stator 526, a rotor 730, and a motor fan 734. The rotor shaft 722 extends along the motor axis A2 and can be engaged with a transmission device (not shown) of the power tool to drive the working operation. The stator can be energized under the control of the controller to cause the rotor 730 to rotate. The rotor 730 is mounted on the rotor shaft 722 via the motor fan 734, so that the rotation of the rotor 730 drives the rotor shaft 722 to rotate. Specifically, in the illustrated embodiment, the motor fan 734 is integrally formed with the rotor 730.

[0060] like Figure 12 and 13 As shown, the rotor 730 includes a rotor core 742 and a plurality of magnets 746. The rotor core 742 can be Figure 5-7B 746 are formed by any process described for the rotor core 542. Magnets 746 are coupled to the rotor core 742 to form or create a plurality of rotor poles 750 on the rotor core 742. In the illustrated embodiment, the magnets 746 are coupled to the rotor core 742 by an overmolding process that creates an overmolded shell 754. In the illustrated embodiment, each rotor pole 750 includes a plurality of magnets 746. Specifically, each rotor pole 750 includes two magnets 746. Thus, the overmolded shell 754 holds the two magnets 746 together at each rotor pole 750 and secures each of the plurality of magnets 746 relative to the rotor core 742. In addition, the overmolded shell 754 defines a window or opening 758 at an inwardly facing surface of each magnet 746 (i.e., the surface of the magnet 746 opposite the rotor core 742) that exposes at least a portion of the magnet 746 to the stator for magnetic engagement with the stator. The motor 714 having a pole 750 with multiple magnets 746 can be advantageously used in power tools having applications where high output torque is required because the pole 750 with multiple magnets 746 can achieve a higher torque output than a single pole. Therefore, the pole 750 with multiple magnets 746 can be advantageously used in motors for power tools (e.g., rotary tools, rotary impact tools, and other similar tools where high torque output is preferred over rotational speed). In some embodiments, the magnets 746 can be coupled to the rotor core 742 by an overmolding process that forms an overmolded housing that supports the rotor poles with only a single magnet.

[0061] Reference Figure 11The motor fan 734 includes a hub 762, a plurality of fan blades 766, and a sidewall 770. The hub 762, the plurality of fan blades 766, and the sidewall 770 are all formed together by molding. The hub 762 includes a hole for mounting the motor fan 734 on the rotor shaft 722. Therefore, the motor axis A2 extends through the center of the hole and, thereby, extends through the center of the hub 762. In the illustrated embodiment, the hub 762 is directly mounted to the rotor shaft 722 to drive the rotation of the rotor shaft 722. In other embodiments, the hub 762 can be mounted to the rotor shaft 722 using bearings or bushings. The fan blades 766 are equally spaced around the hub 762 and extend between the hub 762 and the sidewall 770. Therefore, the fan blades 766 define air gaps 778 between adjacent fan blades 766 to allow cooling air to pass therethrough. Sidewall 770 is integrally formed with overmold shell 754 so that motor fan 734 can be formed onto rotor core 742 simultaneously with overmold shell 754. Alternatively, motor fan 734 can be formed and attached (e.g., by overmolding) thereto after overmold shell 754 is formed.

[0062] refer to Figure 11 , the blower assembly 718 includes a plurality of blower fan blades 782. In the illustrated embodiment, the plurality of blower fan blades 782 are overmolded with the overmolded shell 754 of the rotor core 742. The blower fan blades 782 can be overmolded directly with the overmolded shell 754 in a single overmolding process, wherein the overmolded shell 754 and the blower fan blades 782 are formed simultaneously. Alternatively, the overmolded shell 754 can be formed in a first overmolding process, and the blower fan blades 782 can be formed and attached to the overmolded shell 754 in a second or subsequent overmolding process after the first overmolding process is completed.

[0063] In some embodiments, the blower fan blades 782 can be attached to the overmolded shell 754 of the rotor core 742 by means other than overmolding. For example, the blower fan blades 782 can be snap-fitted to the overmolded shell 754. That is, the overmolded shell 754 can include grooves or other similar features to compatibly receive the blower fan blades 782 in a snap-fit ​​engagement. In another example, the blower assembly 718 can include fasteners, such as screws, to secure each blower fan blade 782 to the overmolded shell 754. In a further example, the blower fan blades 782 can be press-fitted to the overmolded shell 754. In another example, the blower fan blades 782 can be glued to the overmolded shell 754. In another example, the blower fan blades 782 can be ultrasonically plastic welded to the overmolded shell 754.

[0064] Figure 14 Shows the manufacturing Figure 11 Although the steps of the method 800 are disclosed herein in a particular order, it should be understood that the steps do not need to be completed in the order disclosed herein unless otherwise specified.

[0065] refer to Figure 11 and 14 At step 810, method 800 includes providing a rotor shaft 722 and a stator mounted to the rotor shaft 722. Step 820 includes forming the rotor core 742. In the illustrated embodiment, Figure 10 Similar to step 620 of method 600, step 820 includes providing a plurality of laminations, forming a protrusion in each lamination, and stacking the laminations together such that the protrusion of each lamination extends into a gap formed by the protrusions of adjacent laminations. In other embodiments, step 820 may include gluing the laminations together in a face-to-face orientation such that a face of each lamination is glued to a face of an adjacent lamination. In other embodiments, step 820 may include machining the rotor core 742 by, for example, die casting the rotor core 742. In other embodiments, step 820 may include forming the rotor core 742 by a powder metallurgy process, wherein powdered metal may be sintered together to form the rotor core 742.

[0066] Once the main body of the rotor core 742 is formed, a plurality of magnets 746 can be attached to the rotor core 742. Specifically, the magnets 746 and the main body of the rotor core 742 can be overmolded to form an overmolded housing 754 that secures the magnets 746 relative to the rotor core 742. In the illustrated embodiment, the overmolded housing 754 forms poles 750, each having two magnets 746. In other embodiments, the overmolded housing 754 can form poles having more or fewer magnets.

[0067] In the illustrated embodiment, forming the overmolded housing 754 may also include forming the motor fan 734. That is, the motor fan 734 may be formed as the rotor core 742 and the magnets 746 are overmolded, such that the motor fan 734 and the overmolded housing 754 are integrally formed. In other embodiments, the overmolded housing 754 and the motor fan 734 may be formed by separate molding processes and then molded together to attach the motor fan 734 to the rotor core 742.

[0068] Step 830 includes positioning the stator within the rotor core 742. Specifically, step 830 includes positioning the stator so that the rotor core 742 surrounds at least a portion of the stator. Step 840 includes attaching the rotor core 742 to the rotor shaft 722. In the illustrated embodiment, step 840 includes mounting the hub 762 of the motor-fan 734 to the rotor shaft 722. In other embodiments, step 840 may include attaching an end cap to the rotor core 742 and mounting the end cap to the rotor shaft 722.

[0069] Step 850 includes attaching the blower assembly 718 to the motor 714. In the illustrated embodiment, step 850 can be completed simultaneously with forming the rotor core 742, and more specifically, simultaneously with overmolding the magnets 746 onto the rotor core 742. In this way, the overmolded shell 754, the motor fan 734, and the blower fan blades 782 can all be integrally molded together. Alternatively, the blower fan blades 782 can be molded separately from the overmolded shell 754 and then overmolded onto the overmolded shell 754. In this case, the blower fan blades 782 can be molded onto the overmolded shell 754 before, simultaneously with, or after the motor fan 734 is molded onto the overmolded shell 754.

[0070] In some embodiments, the blower fan blades 782 can be attached to the motor 714 by a snap fit. In other embodiments, the blower fan blades 782 can be attached to the motor 714 by fasteners, such as screws, that secure the blades 782 to the overmolded housing 754. In further embodiments, the blower fan blades 782 can be attached to the motor 714 by a press fit. In still other embodiments, the blower fan blades 782 can be attached to the motor 714 by gluing the blades 782 to the overmolded housing 754. In still other embodiments, the blower fan blades 782 can be attached to the motor 714 by ultrasonic plastic welding.

[0071] Figure 15 Another embodiment of a motor fan 910 is shown. The motor fan 910 may replace Figure 5 The motor fan 534 for the motor 514 and / or may replace Figure 11The motor fan 734 for the motor 714 is used. The motor fan 910 includes a hub 914, a plurality of fan blades 918, and a bracket 922 extending around the motor axis A3 at a position radially outward from the hub 914. The motor fan 910 is a centrifugal fan and does not include sidewalls at the radially outward ends of the fan blades 918. Instead, the fan blades 918 are coupled to the rotor core 926 at the front ends of the fan blades 918. Therefore, the motor fan 910 is configured to centrifugally direct airflow through the motor 930. That is, the rotation of the motor fan 910 directs air to flow axially from a position in front of the motor 930 to reach the motor fan 910. The motor fan 910 can then discharge the air radially outward from the motor fan 910. In the illustrated embodiment, all components of the motor 930 are contained within the outer diameter of the rotor.

[0072] Figure 16 An end cap 1010 is shown for use with a motor 1014. Thus, the end cap 1010 may replace Figure 5 The motor fan 534 for the motor 514 and / or may replace Figure 11 The motor fan 734 for the motor 714 is used. In some embodiments, the end cap 1010 can be used with the motor fan. The end cap 1010 can be coupled to the rotor core 1018 and mounted to the rotor shaft (e.g., Figure 5 7 ) such that the rotor core 1018 drives the rotation of the rotor shaft through the end cap 1010. The end cap 1010 includes a plurality of vents 1022 that provide openings for airflow therethrough. Thus, the motor 1014 does not include a dedicated fan for cooling the motor 1014. Instead, the motor 1014 is cooled by a blower assembly (e.g., Figure 5 Blower assembly 518 or Figure 11 The airflow caused by the blower assembly 718 can flow through the vents 1022 and through the motor 1014 to cool the motor 1014. In the embodiment shown, all components of the motor 1014 are contained within the outer diameter of the rotor.

[0073] Figure 17 FIG. 1 shows a rotor 1110 according to another embodiment of the present disclosure. The rotor 1110 may replace Figure 5 The rotor 530 for the motor 514 and / or may replace Figure 11 The rotor 730 for the motor 714 is used. The rotor 1110 includes a rotor core 1114 and magnets 1118 attached to the rotor core 1114. In the embodiment shown, the rotor core 1114 is formed from laminations, similar to the embodiment described with respect to FIG. Figure 6 and 7A542 of the rotor core. In other embodiments, the rotor core 1114 can be formed as a solid body (e.g., by machining or powder metallurgy). The magnets 1118 can be glued to the inner circumferential surface 1114a of the rotor core 1114 and form the magnetic poles 1122. The rotor core 1114 also includes steel attachments 1126, which form the consequent poles 1130. Specifically, the rotor core 1114 alternates between the magnetic poles 1122 and the consequent poles 1130. Including the consequent poles 1130 enables the manufacturer to change the performance indicators of the motor, as will be further described. In the illustrated embodiment, the rotor 1110 uses less magnetic material than a conventional rotor (e.g., 50% less magnetic material) without significantly affecting the performance of the associated motor.

[0074] Figure 18 The efficiency, current, speed in revolutions per minute ("RPM"), and output power in watts ("W") according to some embodiments are compared to a motor with conventional poles (e.g., Figure 5 Rotor 530 or Figure 11 730) and a motor having consequent poles (e.g., Figure 17 110). In some embodiments, the motor represented in graph 1200 is a core drill motor. Graph 1200 includes efficiency representations of several different motors within power tool 100. Curve 1204 shows a motor with a rotor having consequent poles (e.g., Figure 17 Curve 1208 shows the efficiency of a motor with a rotor having conventional poles (e.g., Figure 5 In some embodiments, curve 1204 is a graph having a rotor 530. Figure 17 The efficiency of the motor of rotor 1110 as the torque value increases. In some embodiments, curve 1208 is a curve having Figure 5 The efficiency of the motor of the rotor 530 increases as the torque value increases. In some embodiments, for a given torque value, Figure 5 The efficiency of the motor of rotor 530 is higher than that of Figure 17 The efficiency of the motor with rotor 1110 decreases at a faster rate.

[0075] Graph 1200 also includes current representations for several different motors within power tool 100. Curve 1212 shows a motor with a rotor having consequent poles (e.g., Figure 17 Curve 1216 shows the current of a motor with a rotor having conventional poles (e.g. Figure 5 In some embodiments, curve 1216 is a graph having Figure 17 The current level of the motor of the rotor 1110 increases with the torque value. In some embodiments, the curve 1216 is a curve having Figure 5The current of the motor of the rotor 530 increases as the torque value increases. In some embodiments, as the torque increases, Figure 17 The motor of the rotor 1110 and having Figure 5 The currents of both rotors 530 and motors are approximately equal for a given torque value.

[0076] Graph 1200 also includes RPM representations of several different motors within power tool 100. Curve 1220 shows a motor with a rotor having consequent poles (e.g., Figure 17 The RPM of the motor with the rotor 1110 having conventional poles (e.g. Figure 5 In some embodiments, curve 1220 is a graph having Figure 17 The RPM level of the motor of the rotor 1110 as the torque value increases. In some embodiments, the curve 1224 is a Figure 5 The RPM of the motor of the rotor 530 as the torque value increases. In some embodiments, as the torque increases, for a given torque, Figure 5 The RPM of the motor of the rotor 530 starts at a high level and then decreases to a level lower than that with Figure 17 The rotor 1100 decreases at a faster rate as the RPM of the motor decreases.

[0077] The graph 1200 also includes a representation of the output power (in watts) of several different motors within the power tool 100. Curve 1228 shows the output power of a motor with a rotor having consequent poles (e.g., Figure 17 The output power of the motor with the rotor 1110 having conventional poles (e.g. Figure 5 In some embodiments, curve 1228 is a graph having a Figure 17 The output power level of the motor of the rotor 1110 when the torque value increases. In some embodiments, the curve 1232 is a Figure 5 The output power level of the motor of the rotor 530 as the torque value increases. In some embodiments, as the torque increases, Figure 17 The motor of the rotor 1110 and having Figure 5 The output power levels of the motors of the rotor 1110 are approximately equal for a given torque value until the torque value reaches about 0.5 Nm. After the torque value reaches 0.5 Nm, Figure 17 The motor of rotor 1110 starts with a ratio having Figure 5 The rotor 530 allows the motor to operate at higher output power levels.

[0078] Figure 19One of the motors 514 , 714 , 930 disclosed herein is shown for use in a power tool 1300 (eg, power tool 100 , blower, etc.) The power tool 1300 includes stator blades 1305 that direct the airflow generated by the motor 514 , 714 , 930 toward the output of the power tool 1300 .

[0079] Although the present invention describes multiple embodiments of the drive unit with respect to multiple embodiments of the motor and blower assembly, it should be understood that the motor described herein can be used with any blower assembly, and the blower assembly can be used with any motor. In addition, any feature described for one motor can be combined with the other motor.

[0080] The motor and blower assembly structures described herein advantageously allow manufacturers to adjust the frequency response of the drive unit, such as motor resonance and critical motor speed. For example, to adjust the motor resonance, critical motor speed, and other responses of the motor, the manufacturer can change any one or any combination of the following groups of features: cutouts in the rotor core geometry, the addition of fins / anchors to the rotor core geometry, the motor fan blade geometry and / or the blower fan blade geometry, the number of motor fan blades and / or the number of blower fan blades, the number of magnet pairs, the angular, radial, and axial offsets between the fan blades (e.g., motor fan blades and / or blower fan blades) and the magnets, the molding parameters of the overmolding process (e.g., melt temperature, packing time, etc.), the molding compound composition, and the glass filler content. Thus, adjusting these parameters can extend the life of the drive unit by minimizing the loads on rolling elements and fatigue-sensitive components, minimizing fan blade deflection to optimize aerodynamic performance, and reducing noise and vibration.

[0081] The motor and blower assembly structure described herein further advantageously enables the ability to correct rotor and fan imbalance in a single step. Specifically, rotor and fan imbalance can be corrected by removing material or adding material (e.g., through molding). The motor and blower structure further advantageously enhances the length and diameter compactness of the system. For example, by providing the blower fan blades on the outer surface of the rotor's overmolded housing, the compactness of the drive unit is enhanced.

[0082] The motor and blower assembly configuration further maximizes aerodynamic performance. Specifically, the configuration maximizes aerodynamic performance by minimizing the fan hub diameter, which optimizes the effective fan blade length within a given fan outer diameter. That is, because the fan hub diameter is minimized, the fan blades are longer relative to conventional fans. The configuration also maximizes aerodynamic performance by maximizing the diameter of the motor and blower assembly. That is, for example, Figure 5The diameters of the rotor 530 and the blower fan hub 582 may be equal to reduce / eliminate aerodynamic inefficiencies.

[0083] 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 of the disclosure are set forth in the following claims.

Claims

1. A drive unit, characterized in that: The driving unit includes: A motor, comprising: a rotor shaft extending along an axis of rotation, a stator, the stator being mounted to the rotor shaft, and a rotor at least partially surrounding the stator, the rotor having a rotor core, a plurality of magnets, and an overmold housing coupling the plurality of magnets to the rotor core to form poles having more than one magnet per pole; and A blower assembly includes a plurality of blower fan blades, the blower assembly being configured to be driven by the motor.

2. The drive unit according to claim 1, wherein: The motor includes a motor fan, wherein the motor fan and the overmold housing are molded together, and wherein the motor fan couples the rotor to the rotor shaft.

3. The drive unit according to claim 2, wherein: The motor fan is an axial flow fan configured to cause an airflow from behind the motor fan and to blow the airflow in a forward direction along the rotation axis to cool the rotor shaft, the stator, and the rotor.

4. The drive unit according to claim 2, wherein: The motor fan is a centrifugal fan configured to induce an airflow in front of the motor fan so that the airflow passes through and cools the rotor shaft, the stator, and the rotor before reaching the motor fan, and wherein the motor fan is configured to discharge the airflow radially outward from the motor fan.

5. The drive unit according to claim 1, wherein: The motor includes an end shield coupling the rotor to the rotor shaft, and wherein the end shield has a plurality of vents such that the blower assembly is configured to direct airflow through the plurality of vents for cooling the rotor shaft, the stator, and the rotor.

6. The drive unit according to claim 1, wherein: The blower assembly includes a blower fan and a bushing insert-molded into the blower fan, and wherein the bushing is at least partially positioned between the blower fan and the rotor shaft.

7. The drive unit according to claim 1, wherein: The blower assembly includes a blower fan and a locking ring, and wherein the locking ring prevents the blower fan from moving along the rotor shaft.

8. A drive unit, characterized in that: The driving unit includes: A motor, comprising: a rotor shaft extending along an axis of rotation, a stator, the stator being mounted to the rotor shaft, and a rotor at least partially surrounding the stator, the rotor being configured to be driven by the stator, the rotor being coupled to the rotor shaft to drive the rotor shaft in rotation about the rotation axis; and A blower assembly includes a plurality of blower fan blades extending radially outward from an outer surface of the motor.

9. The drive unit according to claim 8, characterized in that The rotor further includes an overmold shell, and the blower fan blades are integrally formed with the overmold shell.

10. The drive unit according to claim 8, characterized in that The blower fan blades are removable from an outer surface of the motor.

11. The drive unit according to claim 10, characterized in that The blower fan blades are attached to an outer surface of the motor by fasteners.

12. The drive unit according to claim 8, wherein: The rotor includes a rotor core, a plurality of magnets, and an overmold shell that secures the plurality of magnets relative to the rotor core, and wherein the overmold shell defines a plurality of windows adjacent to the plurality of magnets such that at least a portion of each of the plurality of magnets is exposed to the stator.

13. The drive unit according to claim 12, characterized in that The motor further includes a motor fan, and wherein both the motor fan and the blower fan blades are integrally formed with the overmolded housing.

14. The drive unit according to claim 8, wherein: The rotor comprises a rotor outer diameter; and All components of the motor are contained within the outer diameter of the rotor.

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