Electric tool and chainsaw

Abstract

The present application provides an electric tool and a chainsaw. The electric tool comprises a motor, a power supply device and an output part, wherein the motor is configured to provide power for the electric tool, the motor comprises a stator and a rotor rotating relative to the stator, and the rotor comprises a rotor core and magnetic steel disposed on the rotor core; the power supply device is at least electrically connected to the motor; the output part is driven by the motor; and the rotor core comprises limiting parts which are arranged at intervals in the direction of an axis L, and the limiting parts are configured to fix the magnetic steel. By using the above technical solution, the mass of the motor is reduced, thereby decreasing motor loss and improving the efficiency of the motor.

Description

Power tools and chainsaws

[0001] This application claims priority to the Chinese patent application filed with the China Patent Office on June 16, 2023, with application number 202310723350.X. The entire contents of the above application are incorporated by reference into this application. Technical Field

[0002] The present application relates to an electric tool and a chain saw, and in particular to an electric tool and a chain saw in which magnets are fixed by limiting portions spaced apart along the axis of a rotor core. Background Art

[0003] High-power power tools, such as chainsaws and snowplows, are increasingly popular in the market. These tools require higher-power, more efficient motors. Consequently, the motors used in these tools are trending towards higher power density, miniaturization, and lightweighting. For high-frequency motors, core losses account for a significant portion of the motor's heat generation, leading to a sharp increase in internal heat generation, abnormal temperature rise, and reduced motor life.

[0004] Due to their superior heat dissipation, outer rotor motors are more suitable for high-power power tools. The permanent magnets in outer rotor motors are located outside the stator, between the stator and the housing. When the rotor runs at high speeds, the permanent magnets are subject to various forces, including centrifugal and electromagnetic forces, which can cause them to fall off the stator. Therefore, additional measures are needed to prevent the permanent magnets from falling off. Furthermore, it is crucial to avoid additional production and processing costs.

[0005] Summary of the Invention

[0006] The present application provides an electric tool and a chain saw that are safer to use. The electric tool and the chain saw can solve the problem of permanent magnets in an outer rotor motor falling off from the stator without incurring additional production and process costs.

[0007] To achieve the above objectives, this application adopts the following technical solutions:

[0008] In a first aspect, the present application provides an electric tool, comprising:

[0009] A motor for providing power to the electric tool, the motor comprising a stator and a rotor rotating relative to the stator, the rotor comprising a rotor core and magnets disposed on the rotor core;

[0010] a power supply device, electrically connected to at least the motor;

[0011] Output part, driven by motor;

[0012] The rotor core includes limiting portions spaced apart along the axis L, and the limiting portions are used to fix the magnetic steel.

[0013] In some embodiments, the limiting portion includes a first limiting portion and a second limiting portion, one of the first limiting portion and the second limiting portion is located at the head portion of the rotor core, and the other is located at the tail portion of the rotor core.

[0014] In some embodiments, the limiting portion includes a first limiting portion and a second limiting portion, one of the first limiting portion and the second limiting portion is located in the middle of the rotor core, and the other is located at the head and / or tail of the rotor core.

[0015] In some embodiments, the limiting portion includes a first limiting portion, and the thickness of the first limiting portion ranges from 1 mm to 2 mm; and / or

[0016] The limiting portion includes a second limiting portion, and the thickness of the second limiting portion ranges from 1 mm to 2 mm.

[0017] In some embodiments, the limiting portion forms a dovetail slot, and the magnetic steel is inserted into the dovetail slot along the axis L of the rotor core.

[0018] In some embodiments, the limiting portion is lower than the magnetic steel in the circumferential direction.

[0019] In some embodiments, the magnetic steel is fan-shaped, including an inner arc and an outer arc, the inner arc and the outer arc are concentrically arranged, and the distance between the center of the inner arc or the outer arc and the axis L of the rotor core is in the range of 50mm-100mm.

[0020] In some embodiments, the rotor core includes a plurality of laminations stacked along the axis L, and the laminations are made of silicon steel.

[0021] In some embodiments, the rotor further includes a fastening sleeve, which is disposed on the outer periphery of the rotor core and does not have the ability to conduct magnetism.

[0022] In some embodiments, the rotor further includes a first fixing member fixed to one end of the rotor core, and the first fixing member is used to constrain the magnetic steel in the axial and circumferential directions.

[0023] In some embodiments, the rotor further includes a second fixing member fixed to the other end of the rotor core, and the second fixing member is used to radially constrain the magnetic steel.

[0024] In some embodiments, the rated output power of the motor is in the range of 3000W-7000W.

[0025] In some embodiments, the maximum speed range of the motor is greater than or equal to 20,000 rpm.

[0026] In some embodiments, the power tool includes at least one of a chain saw, a snow blower, a pruner, a lawn mower, and a DC fan.

[0027] In some embodiments, the motor is an outrunner motor.

[0028] In a second aspect, the present application provides an electric tool, comprising:

[0029] A motor for providing power to the electric tool, the motor comprising a stator and a rotor that rotates relative to the stator and is at least partially disposed outside the stator, the rotor comprising a rotor core and magnets disposed on the rotor core;

[0030] a power supply device, electrically connected to at least the motor;

[0031] Output part, driven by motor;

[0032] The rotor core includes a plurality of laminations arranged along an axis L, and the plurality of laminations have at least two different shapes such that the plurality of laminations at least include a first lamination having a first shape and a second lamination having a second shape.

[0033] In some embodiments, a projection shape of the first laminate on a first plane is different from a projection shape of the second laminate on the first plane; the first plane is perpendicular to the output shaft.

[0034] In a third aspect, the present application provides an electric tool, comprising:

[0035] A motor for providing power to the electric tool, the motor comprising a stator and a rotor rotating relative to the stator, the rotor comprising a rotor core and magnets disposed on the rotor core;

[0036] a power supply device, electrically connected to at least the motor;

[0037] Output part, driven by motor;

[0038] A limiting portion for fixing the magnetic steel is formed on the inner wall of the rotor core, and the ratio of the total length of the limiting portion in the direction of the axis L to the length of the magnetic steel in the direction of the axis L is in the range of 0.01-0.9.

[0039] In some embodiments, the ratio of the total length of the limiting portion in the direction of the axis L to the length of the magnetic steel in the direction of the axis L is in a range of 0.1-0.2.

[0040] In some embodiments, the number of the limiting parts is one or more.

[0041] In a fourth aspect, the present application provides an electric tool, comprising:

[0042] A stator and a rotor rotating relative to the stator, wherein the rotor comprises a rotor core and magnets disposed on the rotor core;

[0043] The rotor core includes limiting portions spaced apart along the axis L, and the limiting portions are used to fix the magnetic steel.

[0044] In some embodiments, the motor is an outrunner motor.

[0045] In some embodiments, the rated power of the motor is greater than or equal to 1000W and less than or equal to 7000W.

[0046] In a fifth aspect, the present application provides a chain saw, comprising:

[0047] case;

[0048] a saw chain and a guide plate, wherein the saw chain is arranged around the outer periphery of the guide plate, one end of the guide plate is supported by the housing, and the other end extends out of the housing along the longitudinal direction of the housing;

[0049] A motor for driving the saw chain to perform cutting;

[0050] The rated speed of the motor is greater than or equal to 10,000 rpm and less than or equal to 20,000 rpm, and the ratio of the rated power of the motor to the weight of the stator of the motor is greater than or equal to 6 W / g and less than or equal to 14 W / g.

[0051] In some embodiments, the rated speed of the motor is greater than or equal to 10,000 rpm and less than or equal to 17,000 rpm.

[0052] In some embodiments, the ratio of the outer diameters of the stator to the rotor is greater than or equal to 0.7.

[0053] In some embodiments, the power density of the motor is greater than or equal to 2000 W / kg.

[0054] In some embodiments, a support member including a rim portion and a spoke portion is provided at the radial center of the stator.

[0055] In some embodiments, a pole arc coefficient of a rotor of the motor is greater than or equal to 0.6 and less than 1.

[0056] In some embodiments, the stator includes a stator core and a stator winding, the stator core has a plurality of radially extending teeth, and the stator winding is wound on the teeth; the teeth have different widths in the radial direction, wherein the width of the tooth is the width of the tooth perpendicular to its extension direction.

[0057] In some embodiments, a ratio of a maximum value to a minimum value of the width of the teeth is greater than 1 and less than or equal to 1.8.

[0058] In some embodiments, the rotor of the motor includes a rotor core and magnets, and the magnets are fixed to the rotor core by plastic coating.

[0059] In some embodiments, the motor further includes a bracket, the stator and the rotor are sleeved on the bracket, the support member is coaxially arranged with the bracket, and the bracket is formed with an air inlet and an air outlet for heat dissipation airflow to pass through.

[0060] In some embodiments, the motor further includes a fan, and the motor further has a motor housing, and the motor housing and the fan are integrally formed.

[0061] In some embodiments, the rotor of the motor includes a rotor core, and an inner wall of the motor housing is formed with a limiting boss for limiting the rotor core in the axial direction.

[0062] In some embodiments, the support member is made of metal or modified plastic.

[0063] In some embodiments, the rotor of the motor is sleeved outside the stator, and the support member is disposed inside the stator to support the stator.

[0064] In some embodiments, the rated output power of the motor is in the range of 3000W-7000W.

[0065] In a sixth aspect, the present application provides an electric tool, comprising:

[0066] case;

[0067] output section; and

[0068] The motor is disposed in the housing, and includes:

[0069] stator, including stator core and stator winding;

[0070] A rotor, comprising a rotor core and magnets, disposed on the periphery of the stator and rotatable relative to the stator; and

[0071] an output shaft coupled to the rotor to drive the output portion;

[0072] The rated speed of the motor is greater than or equal to 20,000 rpm, and the ratio of the motor's rated power to the volume of the stator is greater than or equal to 50 W / cm 3 .

[0073] In some embodiments, the power tool is a hair dryer.

[0074] In some embodiments, the ratio of the outer diameters of the stator to the rotor is greater than or equal to 0.7.

[0075] In a seventh aspect, the present application provides an electric tool, comprising:

[0076] case;

[0077] output section; and

[0078] The motor is arranged in the housing, and includes:

[0079] stator, including stator core and stator winding;

[0080] A rotor, comprising a rotor core and magnets, disposed on the periphery of the stator and rotatable relative to the stator; and

[0081] an output shaft coupled to the rotor to drive the output portion;

[0082] The rated power of the motor is greater than or equal to 3000 W and less than or equal to 7000 W, and the air-gap ratio of the motor is greater than or equal to 0.7.

[0083] In some embodiments, the outer diameter of the rotor is greater than or equal to 35 mm and less than or equal to 105 mm.

[0084] In an eighth aspect, the present application provides an electric tool, comprising:

[0085] A motor is used to provide power for the electric tool, and the motor includes a stator and a rotor rotating relative to the stator; a power supply device is electrically connected to at least the motor; an output part is driven by the motor; and a support member including a rim part and a spoke part is provided at the radial center of the stator.

[0086] In some embodiments, the electric tool further includes a shell having an accommodating space, and the output portion includes a functional component; the motor is disposed in the accommodating space of the shell and drives the functional component to perform a corresponding function.

[0087] In some embodiments, the rotor is sleeved outside the stator, and the support member is disposed inside the stator to support the stator.

[0088] In some embodiments, the support member is made of metal or modified plastic.

[0089] In some embodiments, the ratio of the outer diameters of the stator to the rotor is greater than or equal to 0.7.

[0090] In some embodiments, the pole arc coefficient of the rotor is greater than or equal to 0.6 and less than 1.

[0091] In some embodiments, the power density of the motor is greater than or equal to 2000 W / kg.

[0092] In some embodiments, the stator includes a stator core and a stator winding, the stator core has a plurality of radially extending teeth, and the stator winding is wound on the teeth; the teeth have different widths in the radial direction, wherein the width of the tooth is the width of the tooth perpendicular to its extension direction.

[0093] In some embodiments, a ratio of a maximum value to a minimum value of the width of the teeth is greater than 1 and less than or equal to 1.8.

[0094] In some embodiments, the rotor includes a rotor core and magnets, and the magnets are fixed to the rotor core by plastic coating.

[0095] In some embodiments, the motor further includes a bracket, the stator and the rotor are sleeved on the bracket, the support member is coaxially arranged with the bracket, and the bracket is formed with an air inlet and an air outlet for heat dissipation airflow to pass through.

[0096] In some embodiments, the power tool further includes a fan, and the motor further includes a motor housing, wherein the motor housing and the fan are integrally formed.

[0097] In some embodiments, the rotor includes a rotor core, and an inner wall of the motor housing is formed with a limiting boss for limiting the rotor core in the axial direction.

[0098] The beneficial effects of this application are:

[0099] The present application provides an electric tool, in which the rotor core in the motor of the electric tool includes limiting parts arranged at intervals along the axis L. The limiting parts are used to fix the magnets, thereby solving the problem of the magnets falling off the stator. Compared with the limiting parts of the integrated structure in the related art, the weight of the limiting parts arranged at intervals is effectively reduced, thereby reducing motor losses and improving motor efficiency. BRIEF DESCRIPTION OF THE DRAWINGS

[0100] Figure 1 is a schematic structural diagram of an electric tool;

[0101] FIG2 is a schematic diagram of the structure of a motor;

[0102] FIG3 is a schematic structural diagram of a stator and a rotor in one embodiment;

[0103] FIG4 is a schematic structural diagram of a stator and a magnetic steel from a first perspective in one embodiment;

[0104] FIG5 is an enlarged view of point A in FIG4 ;

[0105] FIG6 is a schematic structural diagram of a stator and a magnetic steel from a second perspective in one embodiment;

[0106] FIG7 is a schematic cross-sectional view of a motor in one embodiment;

[0107] FIG8 is a schematic diagram of a motor stage in one embodiment;

[0108] FIG9 is a schematic diagram of the internal structure of a motor in another embodiment;

[0109] FIG10 is a schematic structural diagram of a rotor from a first perspective in another embodiment;

[0110] FIG11 is a schematic diagram of the exploded structure of a rotor in another embodiment;

[0111] FIG12 is an enlarged view of point B in FIG11;

[0112] FIG13 is a schematic structural diagram of a rotor from a second perspective in another embodiment;

[0113] FIG14 is an exploded view of a motor according to an embodiment;

[0114] FIG15 is a plan view of the stator, rotor, and motor housing of the motor shown in FIG14 ;

[0115] FIG16 is a cross-sectional view of the rotor core, rotor magnets, and plastic components of the motor shown in FIG14 ;

[0116] FIG17 is a cross-sectional view of the motor housing, fan, and limiting boss in the motor shown in FIG14 ;

[0117] FIG18 is a plan view of the stator core and stator windings in the motor shown in FIG14;

[0118] FIG19 is a plan view of the rotor, stator, support member, and output shaft of the motor shown in FIG14 ;

[0119] FIG20 is a perspective view of a support member and a bracket in the motor shown in FIG14 under one embodiment;

[0120] FIG21 is a cross-sectional view of the base, pipe member, support member, and stator core of the motor shown in FIG20 ;

[0121] FIG22 is a perspective view of a bracket in the motor shown in FIG14 according to another embodiment;

[0122] FIG23 is a cross-sectional view of the base, the pipe component, and the output shaft of the motor shown in FIG22 .

[0123] 100, chain saw; 10, housing; 11, rear handle; 111, first switch; 112, second switch; 12, front handle; 13, guard; 14, joint; 15, right housing; 16, left housing; 17, main housing; 21, saw chain; 22, guide bar; 30, power supply;

[0124] 200, motor; 210, stator; 220, rotor; 211, stator core; 212, stator winding; 221, rotor core; 2211, first limiting portion; 2212, second limiting portion; 2213, dovetail groove; 2214, first lamination; 22141, first protrusion; 22142, second protrusion; 2215, second lamination; 222, magnet; 223, first fixing member; 2231, first connecting portion; 2232, first fixing portion; 224, second fixing member; 2241, second connecting portion; 2242, second fixing portion; 225, fastening sleeve; 226, output shaft; 227, plastic part;

[0125] 230, motor housing; 231, fan; 232, limiting boss;

[0126] 240. Support member; 241. Rim portion; 242. Spoke portion; 250. Bracket; 251. Base; 2511. Air inlet; 252. Tube component; 2521. Air outlet. DETAILED DESCRIPTION

[0127] Before any embodiments of the present application are explained in detail, it is to be understood that the application is not limited in its application to the details of construction and the arrangement of components set forth in the following description or illustrated in the foregoing drawings.

[0128] In this application, the terms "comprises," "includes," "has," or any other variations thereof are intended to encompass non-exclusive inclusion, such that a process, method, article, or apparatus that includes a list of elements includes not only those elements but also other elements not explicitly listed, or elements inherent to such process, method, article, or apparatus. In the absence of further limitations, an element defined by the phrase "comprising a ..." does not preclude the presence of additional identical elements in the process, method, article, or apparatus that includes the element.

[0129] In this application, the term "and / or" describes a relationship between related objects, indicating that three possible relationships exist. For example, "A and / or B" can represent: A exists alone, A and B exist simultaneously, or B exists alone. Additionally, the character " / " in this application generally indicates that the related objects are in an "and / or" relationship.

[0130] In this application, the terms "connect," "combine," "couple," and "install" may refer to direct connection, combination, coupling, or installation, or indirect connection, combination, coupling, or installation. For example, a direct connection refers to two parts or components being connected together without an intermediary, and an indirect connection refers to two parts or components being connected to at least one intermediary, with the two parts or components being connected via the intermediary. Furthermore, "connect" and "couple" are not limited to physical or mechanical connections or couplings and may include electrical connections or couplings.

[0131] In this application, it will be understood by those skilled in the art that relative terms (e.g., "about," "approximately," "substantially," etc.) used in conjunction with quantities or conditions include the values ​​and have the meaning indicated by the context. For example, the relative terms include at least the degree of error associated with the measurement of a specific value, the tolerance caused by manufacturing, assembly, use, etc. associated with a specific value. Such terms should also be considered to disclose a range defined by the absolute values ​​of the two endpoints. Relative terms may refer to plus or minus a certain percentage (e.g., 1%, 5%, 10% or more) of the indicated value. Numerical values ​​that do not use relative terms should also be disclosed as specific values ​​with tolerances. In addition, "substantially" may refer to plus or minus a certain degree (e.g., 1 degree, 5 degrees, 10 degrees or more) on the basis of the indicated angle when expressing a relative angular position relationship (e.g., substantially parallel, substantially perpendicular).

[0132] In this application, it will be understood by those skilled in the art that the function performed by an assembly can be performed by one assembly, multiple assemblies, one part, or multiple parts. Similarly, the function performed by a part can also be performed by one part, one assembly, or a combination of multiple parts.

[0133] In the present application, the terms "upper", "lower", "left", "right", "front", "back" and other directional words are described based on the orientation and positional relationship shown in the accompanying drawings, and should not be understood as limiting the embodiments of the present application. In addition, in the context, it is also necessary to understand that when it is mentioned that an element is connected to another element "upper" or "lower", it can not only be directly connected to the other element "upper" or "lower", but also be indirectly connected to the other element "upper" or "lower" through an intermediate element. It should also be understood that directional words such as upper side, lower side, left side, right side, front side, back side, etc. not only represent the positive orientation, but can also be understood as the lateral orientation. For example, below can include directly below, lower left, lower right, lower front and lower back, etc.

[0134] FIG1 illustrates a specific embodiment of a power tool in this application. In practice, the motor in this application is applicable to handheld power tools such as electric drills, electric wrenches, electric screwdrivers, electric hammer drills, electric circular saws, and sanders; benchtop tools such as table saws; and outdoor tools such as lawn mowers, snow blowers, mowers, electric shears, pruners, chainsaws 100, and pole saws. The motor in this application is also applicable to DC fans, high-pressure washers, and all-terrain vehicles. Obviously, the following embodiments are only some of the embodiments of this application, and are not exhaustive.

[0135] As shown in FIG1 , a chainsaw 100 includes a housing 10, a saw chain 21, a sprocket supported within the housing 10 and capable of driving the saw chain 21, and a guide plate 22 that supports and guides the saw chain 21. In some embodiments, the housing 10 includes a right housing 15 and a left housing 16. The right and left housings 15 and 16 are assembled in a left-right direction to form the housing 10 and a first storage space. The housing 10 includes a main housing portion 17, which forms or is connected to a rear handle 11 for the user to grasp, and a front handle 12 for the user to lift and operate the chainsaw 100 in conjunction with the rear handle 11. In some embodiments, the rear handle 11 is connected to a switch for controlling the operating state of the chainsaw 100. Specifically, the switch includes a first switch 111 and a second switch 112. The chainsaw 100 can only be activated when the user presses the first and second switches 111 and 112 simultaneously, thereby preventing accidents caused by the user accidentally touching the first switch 111 while holding the chainsaw 100. In some embodiments, the second switch 112 is generally used as a safety start switch, and the first switch 111 is generally used as a power-on and speed adjustment switch. It is understood that when using the chain saw 100, the user presses the second switch 112 with his thumb and presses the first switch 111 with his index or middle finger to start and adjust the speed.

[0136] The chainsaw 100 also includes a guard 13 disposed on the front side of the front handle 12. The guard 13 protects the user from being cut by the saw chain 21 due to the recoil force when operating the chainsaw 100. When the chainsaw 100 is in operation, some flying debris (e.g., sawdust) may scratch the surface of the user's hand while gripping the front handle 12.

[0137] The chainsaw 100 also includes a power supply device 30 that provides the chainsaw 100 with the electrical energy required for operation. The power supply device 30 includes a battery pack, which is detachably connected to the joint 14 formed by the housing 10. It should be understood that the power supply device 30 is not limited to the scenario of using a battery pack, and can also be powered by AC power, AC power, and corresponding rectification, filtering and voltage regulation circuits to achieve power supply to various circuit elements. In some embodiments, the power supply device 30 includes multiple battery packs to provide the chainsaw 100 with a longer battery life and a larger output power. Specifically, the total energy of the power supply device 30 is greater than or equal to 20Wh. The maximum rated voltage of the power supply device 30 is set to be greater than or equal to 40V and less than or equal to 100V.

[0138] As shown in Figures 1 and 2, the chainsaw 100 also includes a first drive unit for outputting power. In this embodiment, the first drive unit includes at least a motor, which may also be referred to as an electric motor 200. For ease of description, the electric motor 200 will be used as an example. The electric motor 200 is disposed within the main housing portion 17. Specifically, the electric motor 200 has an output shaft 226, which is used to rotate a sprocket. The sprocket drives a saw chain 21, which wraps around the edge of a guide plate 22 and is guided in a circular motion by the guide plate 22. The guide plate 22 is generally arranged in a front-to-back direction, with one end supported by the housing 10 and the other end extending longitudinally out of the housing 10. Chain saws 100 driven by the motor 200, particularly those driven by direct current, are relatively heavy after the power supply unit 30 is installed due to the inherent structural limitations of the chainsaw 100. To reduce user fatigue from prolonged operation of the chainsaw 100, the center of gravity of the chainsaw 100 should be positioned close to the front handle 12. Specifically, the motor 200 and the saw chain 21 of the chain saw 100 are disposed at the front end of the chain saw 100. The power supply device 30 is disposed at the rear end of the chain saw 100 relative to the motor 200. The rear handle 11 is disposed on the upper side of the power supply device 30.

[0139] In some embodiments, the rated output power of motor 200 is in the range of 3000W to 7000W, and the maximum speed is greater than or equal to 20,000 rpm. The rotor diameter of motor 200 is greater than or equal to 50 mm and less than or equal to 105 mm. Optionally, the rotor diameter of motor 200 is greater than or equal to 80 mm and less than or equal to 95 mm. The rated power of motor 200 is greater than or equal to 1000W and less than or equal to 7000W.

[0140] Referring to Figures 2 to 8 , regarding the structure of the motor 200, in this embodiment, the motor 200 includes a stator 210 and a rotor 220 disposed at least partially outside the stator 210 and rotatable relative to the stator 210. The rotor 220 includes a clamping sleeve 225 and a magnet 222 disposed within the clamping sleeve 225. The motor 200 is electrically connected to a power supply 30, and the motor 200 is powered by the power supply 30. The output portion includes a saw chain 21, which is directly or indirectly driven by the motor 200. Optionally, the motor 200 is an outer rotor motor.

[0141] The fastening sleeve 225 is made of a non-magnetic material, specifically a non-magnetic metal or non-metallic material. Compared to magnetic materials, non-magnetic materials offer a wider range of options and have a lower relative density, resulting in a lighter motor 200. This reduces the overall weight of the power tool and improves ease of use. There are multiple magnets 222, each of which has multiple poles. The multiple pole magnets 222 are arranged in a ring around the axis L and are connected end-to-end. Each pole magnet 222 has multiple magnets 222 with different magnetic pole orientations.

[0142] In some embodiments, as shown in Figures 3 and 4 , multiple magnets 222 are arranged in a ring around an axis L on the inner wall of a fastening sleeve 225. The multiple magnets 222 form multiple magnetic poles, and at least two magnets 222 in each pole have different magnetization directions. Thus, compared to traditional motor architectures, the magnetization directions of the magnets 222 in this application are configured to significantly increase the magnetic field strength on one side of the magnets 222 and significantly weaken it on the other side, effectively reducing the size of the motor and increasing its power density. Optionally, the magnets 222 in this application utilize a Halbach magnet array.

[0143] As shown in FIG5 , three magnets a, b, and c form a magnetic pole, wherein the three magnets 222 in each magnetic pole have different magnetization directions. The arrows indicate the magnetization directions of the magnets 222. It should be noted that the magnets 222 in each magnetic pole can also be of different sizes.

[0144] In some embodiments, each pole magnetic steel 222 includes M magnetic steels 222 , where M is greater than or equal to 2 and less than or equal to 7. The number of magnetic steels 222 per pole can be set based on actual needs and is not limited thereto. In some embodiments, each pole magnetic steel 222 includes M magnetic steels 222 , where M is greater than or equal to 4 and less than or equal to 5. In this embodiment, each pole magnetic steel 222 includes five magnetic steels 222 . The magnetic pole orientation of each magnetic steel 222 per pole magnetic steel 222 is different, and the specific magnetic pole orientation can be set based on actual needs. The method for determining the magnetic pole orientation is well known to those skilled in the art and will not be further described here.

[0145] In some embodiments, the cross-sectional shape of the windings on the stator 210 is polygonal or circular. For example, the cross-sectional shape of the windings on the stator 210 is triangular, quadrilateral, or pentagonal. If the cross-sectional shape of the windings on the stator 210 is quadrilateral, it may be rectangular or square. In some embodiments, the cross-sectional shape of the windings on the stator 210 may be hexagonal, heptagonal, or even octagonal.

[0146] In some embodiments, the windings on the stator 210 are formed in a flat-wound or vertical-wound manner.

[0147] The winding leads on stator 210 are connected via a manifold or PCB. PCB connection simplifies assembly, improves interchangeability and maintainability, and is suitable for standardized mass production. Manifold connection offers excellent connection stability and vibration resistance, making it suitable for harsh operating conditions. When using the lead-out method, consider the overall structure of motor 200 and the application scenario to appropriately select the lead-out method.

[0148] In some embodiments, stator 210 is made of an amorphous alloy or nanocrystalline material. Amorphous alloys offer excellent performance and simple processing, surpassing silicon steel in terms of magnetic permeability and iron loss. Nanocrystalline materials, with their excellent physical and chemical properties, can significantly improve the performance and efficiency of motor 200.

[0149] In some embodiments, the angle between the two opposing faces of any two adjacent magnetic steels 222 is X, where X is greater than or equal to 0° and less than or equal to 5°. With this angle setting, the gap between two adjacent magnetic steels 222 can be appropriately adjusted, thereby reducing the manufacturing difficulty and cost of the magnetic steels 222. In some embodiments, the angle between the two opposing faces of any two adjacent magnetic steels 222 is X, where X is equal to 0°. This setting gives each magnetic steel 222 a fan-shaped structure, maximizing the volume of the magnetic steel 222 and helping to increase the power density of the motor 200.

[0150] As shown in Figures 7 and 8, in some embodiments, the rotor 220 further includes a first fixing member 223, which is fixed to one end of the fastening sleeve 225. The first fixing member 223 is used to axially and / or circumferentially constrain the magnet 222. This arrangement stabilizes the magnet 222 relative to the stator 210 and improves safety. Specifically, the first fixing member 223 includes a first connecting portion 2231 and a first fixing portion 2232 connected to the first connecting portion 2231. The first connecting portion 2231 is connected to the fastening sleeve 225, and the first fixing portion 2232 is used to constrain the magnet 222. In this embodiment, the first fixing portion 2232 is strip-shaped and is provided in plurality. The plurality of first fixing portions 2232 are evenly arranged around the axis L. Every two adjacent first fixing portions 2232 and the first connecting portion 2231 form a fixing slot. One end of the magnet 222 is positioned within the fixing slot and is constrained circumferentially by the two sidewalls of the fixing slot and axially by the first connecting portion 2231. The first fixing member 223 in this embodiment is only applicable to implementations in which the angle between adjacent magnetic steels 222 is not zero.

[0151] In this embodiment, the first connecting portion 2231 and the first fixing portion 2232 are integrally formed.

[0152] The rotor 220 also includes a second fixing member 224, which is fixed to the other end of the fastening sleeve 225 and is used to radially constrain the magnet 222. Specifically, the second fixing member 224 includes a second connecting portion 2241 and a second fixing portion 2242 disposed on the second connecting portion 2241. The second connecting portion 2241 is connected to the fastening sleeve 225, and the second fixing portion 2242 is used to constrain the magnet 222. In this embodiment, the second fixing portion 2242 is a retaining groove disposed on the second connecting portion 2241. There are multiple retaining grooves, which are evenly arranged around the axis L. Each retaining groove has a groove bottom, two circumferential sidewalls, and two radial sidewalls. The other end of the magnet 222 is located in the retaining groove. The magnet 222 is axially constrained by the groove bottom, circumferentially constrained by the circumferential sidewalls, and radially constrained by the radial sidewalls. In some embodiments, the limiting groove can be annular. The other ends of all the magnetic steels 222 are fixed in the limiting groove. In this embodiment, the limiting groove can be applicable to implementations in which the angle between the magnetic steels 222 is zero or non-zero.

[0153] In this embodiment, the second connecting portion 2241 and the second fixing portion 2242 are integrally formed.

[0154] In the embodiments shown in FIG. 7 and FIG. 8 , the magnetic steel 222 may not be a Halbach magnet array.

[0155] 9 to 13 , in some embodiments, a motor 200 includes a stator 210 and a rotor 220 that rotates relative to the stator 210. The rotor 220 includes a rotor core 221 and magnets 222 disposed on the rotor core 221. The rotor core 221 includes stoppers spaced apart along the axis L, which are used to secure the magnets 222. The stoppers secure the magnets 222, preventing them from falling off the rotor 220. Compared to the stoppers of the integrated structure of the related art, the spaced stoppers effectively reduce weight, thereby reducing losses in the motor 200 and improving its efficiency.

[0156] In some embodiments, the limiting portion includes a first limiting portion 2211 and a second limiting portion 2212, one of which is located at the head of the rotor core 221, and the other is located at the tail of the rotor core 221. This arrangement can support both ends of the magnetic steel 222 and improve the stability of the magnetic steel 222.

[0157] In some embodiments, the limiting portion includes a first limiting portion 2211 and a second limiting portion 2212, one of which is located in the middle of the rotor core 221, and the other is located at the head and / or tail of the rotor core 221. In this embodiment, three embodiments can be provided regarding the positional relationship between the first limiting portion 2211 and the second limiting portion 2212. In a first embodiment, the limiting portion includes a first limiting portion 2211 and a second limiting portion 2212, one of which is located in the middle of the rotor core 221, and the other is located at the head of the rotor core 221. In a second embodiment, the limiting portion includes a first limiting portion 2211 and a second limiting portion 2212, one of which is located in the middle of the rotor core 221, and the other is located at the tail of the rotor core 221. In the third embodiment, the limiting portion includes a first limiting portion 2211 and a second limiting portion 2212. One of the first limiting portion 2211 and the second limiting portion 2212 is located in the middle of the rotor core 221, and the other is located at the front and rear ends of the rotor core 221. In the third embodiment, for example, the first limiting portion 2211 is located in the middle of the rotor core 221, and there are two second limiting portions 2212, one at the front and one at the rear end of the rotor core 221. This arrangement provides support for the magnet 222 at the front, middle, and rear ends, making it more secure.

[0158] In some embodiments, the limiting portion includes a first limiting portion 2211, and the thickness of the first limiting portion 2211 ranges from 1 mm to 2 mm. In this embodiment, the thickness of the first limiting portion 2211 refers to the dimension of the first limiting portion 2211 along the axis L. The limiting portion includes a second limiting portion 2212, and the thickness of the second limiting portion 2212 ranges from 1 mm to 2 mm. In this embodiment, the thickness of the second limiting portion 2212 refers to the dimension of the second limiting portion 2212 along the axis L. The thickness dimensions of the first limiting portion 2211 and the second limiting portion 2212 may be the same or different. When they are the same, they may both be 1.5 mm. In other embodiments, the thickness dimensions of the first limiting portion 2211 and the second limiting portion 2212 may also both be 0.5 mm, 2.1 mm, 3 mm or 5 mm.

[0159] In some embodiments, the length of the stopper is defined from a ratio perspective, where the ratio of the total length of the stopper along the axis L to the length of the magnetic steel 222 along the axis L is in a range of 0.01-0.9. In some embodiments, the ratio of the total length of the stopper along the axis L to the length of the magnetic steel 222 along the axis L is in a range of 0.1-0.2.

[0160] In some embodiments, the number of the limiting parts is one or more. When there is one limiting part, the length of the limiting part can be appropriately larger, and when there are multiple limiting parts, the length of the limiting part can be appropriately smaller.

[0161] As shown in Figures 12 and 13 , the retaining portion forms a dovetail slot 2213, into which the magnet 222 is inserted along the axis L of the rotor core 221. The provision of the dovetail slot 2213 helps radially limit the magnet 222, thereby preventing the magnet 222 from moving radially in the rotor core 221. Specifically, the dovetail slot 2213 can have a trapezoidal or triangular shape. In other words, the distance between the two sidewalls of the dovetail slot 2213 can gradually decrease as it approaches the axis L, or can initially increase and then decrease.

[0162] In some embodiments, the stopper is circumferentially lower than the magnet 222. In other words, in the radial direction of the motor 200, the depth of the dovetail slot 2213 is less than the thickness of the magnet 222. This arrangement prevents excessively high stoppers from affecting the stator 210. While maintaining the gap between the stator 210 and the rotor 220, the thickness of the magnet 222 can be increased as much as possible, thereby improving the performance of the motor 200.

[0163] In some embodiments, the magnet 222 is fan-shaped, including an inner arc and an outer arc. The inner and outer arcs are concentrically arranged, and the distance between the center of the inner or outer arc and the axis L of the rotor core 221 ranges from 50 mm to 100 mm. This arrangement allows the magnet 222 to better fit within the trapezoidal dovetail slot 2213. In other embodiments, the shape of the magnet 222 is not limited to a fan-shaped shape and can be configured based on the structure of the dovetail slot 2213.

[0164] As shown in Figures 9 and 12 , the rotor core 221 includes a plurality of laminations stacked along the axis L. The laminations are made of silicon steel. The laminations have at least two different shapes. The laminations include a first lamination 2214 having a first shape and a second lamination 2215 having a second shape. The first lamination 2214 and the second lamination 2215 have different projections on a first plane. The first plane is perpendicular to the output shaft 226. The first lamination 2214 has a first protrusion 22141 and a second protrusion 22142. After stacking the first laminations 2214, the first protrusions 22141 form the first stopper 2211 or the second stopper 2212. The second lamination 2215 also has a second protrusion 22142. After stacking the first laminations 2214 and the second laminations 2215, the second protrusions 22142 form a clamping platform. The clamping platform can cooperate with the clamping groove of the fastening sleeve 225 to prevent the rotor core 221 from rotating relative to the fastening sleeve 225 about the axis L. The laminations can also be made of other materials and are not limited to the materials listed above. The laminations can also have three or four shapes and are not limited to the above embodiment.

[0165] The rotor 220 further includes a fastening sleeve 225, which is sleeved on the outer periphery of the rotor core 221. The fastening sleeve 225 does not have the ability to conduct magnetic fields. This arrangement makes the rotor core 221 composed of laminated sheets more secure.

[0166] In some embodiments, the first fixing member 223 and the second fixing member 224 may also be fixed on the rotor core 221 .

[0167] In some embodiments, referring to Figures 14 to 23 , the stator and rotor 210 and 220 are nested within each other. In the case of an external rotor motor, the stator 210 is radially inner, and the rotor 220 is at least partially disposed outside the stator 210 and rotates relative to the stator 210. In the case of an internal rotor 220 motor, the stator 210 is radially outer, and the rotor 220 is at least partially disposed inside the stator 210 and rotates relative to the stator 210. In some embodiments, the motor is a brushless motor. In some embodiments, the motor is a permanent magnet synchronous motor. The following mainly describes an outer rotor permanent magnet synchronous motor, in which the rotor 220 includes a rotor core 221 and a magnet 222 fixed on the rotor core 221, and the stator 210 includes a stator core 211 and a stator winding 212 wound on the stator core 211. The rotor core 221 and the magnet 222 of the rotor 220 are arranged outside the above-mentioned stator core 211 and stator winding 212 of the stator 210.

[0168] In the present application, a support member 240 having a rim and spoke structure is added to the power tool motor 200. As shown in FIG19 , the support member 240 is provided at the radial center of the stator 210 and includes a rim portion 241 and a spoke portion 242. The rim portion 241 constitutes the outer edge of the support member 240, and the spoke portion 242 is connected to the rim portion 241 within the rim portion 241 and forms a through hole for the output shaft 226 to pass through. In some embodiments, taking the above-mentioned outer rotor permanent magnet synchronous motor as an example, the support member 240 can support the stator 210 located at its outer periphery. The rim portion 241 supports the stator core 211, and the spoke portion 242 includes a plurality of spokes extending radially inward from the rim portion 241. The plurality of spokes do not intersect and form a through hole at the radial center of the stator 210 for the output shaft 226 to pass through. In some embodiments, the rim portion 241 includes an inner rim and an outer rim. The outer rim supports the stator core 211, while the inner rim defines a through-hole for the output shaft 226 to pass through. Multiple spokes of the spoke portion 242 connect between these inner and outer rims. This support member 240, with its rim and spoke structure, creates a substantial hollow space within the stator and rotor 210, 220 of the motor 200. This significantly improves heat dissipation compared to conventional bearing support solutions, while also reducing weight and costs.

[0169] In some embodiments, the support member is made of metal or modified plastic. The metal or modified plastic used is lightweight and has good heat dissipation properties, thereby better achieving the improvements described above and facilitating process implementation. In some embodiments, the support member is aluminum. In other embodiments, the support member is made of thermoplastic or thermosetting plastic.

[0170] In some embodiments, the power density of the motor 200 is greater than or equal to 2000W / kg. Preferably, in some embodiments, the power density of the motor 200 is greater than or equal to 3000W / kg. The power density of the motor 200 may be the ratio between its rated power and the mass of its necessary components. In some embodiments, the no-load speed of the motor 200 is greater than or equal to 10000rpm and less than or equal to 17000rpm. In some further embodiments, the outer diameter of the motor 200 is greater than or equal to 50mm. Preferably, in some embodiments, the outer diameter of the motor 200 is greater than or equal to 50mm and less than or equal to 105mm. Preferably, in some embodiments, the outer diameter of the motor 200 is greater than or equal to 80mm and less than or equal to 95mm.

[0171] In some embodiments, the motor 200 is an outer rotor motor, and the ratio of the outer diameter D1 of the stator 210 of the motor 200 to the outer diameter D2 of the rotor 220 is greater than or equal to 0.7 and less than 1. As shown in Figures 15 and 16 , the outer diameter D1 of the stator 210 of the motor 200 may be the outer diameter of its stator core 211, and the outer diameter D2 of the rotor 220 may be the outer diameter of the rotor core 221. Preferably, in some embodiments, the ratio of the outer diameter D1 of the stator 210 of the motor 200 to the outer diameter D2 of the rotor 220 is greater than or equal to 0.8 and less than 1, so that the stator and rotor 210 and 220 form the motor 200 more compactly, thereby reducing the size of the motor 200.

[0172] In some embodiments, the pole arc coefficient of the rotor 220 of the motor 200 is greater than or equal to 0.6 and less than 1. The pole arc coefficient of a permanent magnet synchronous motor can be defined by the arc length and pole pitch of its rotor magnet 222. As shown in FIG16 , the pole arc coefficient of the rotor 220 is the ratio of the arc length α of the rotor magnet 222 to the pole pitch β corresponding to the rotor magnet 222. Preferably, in some embodiments, the pole arc coefficient of the rotor 220 of the motor 200 is greater than or equal to 0.7 and less than 1.

[0173] In some embodiments, the magnets 222 in the rotor 220 are secured to the rotor core 221 by overmolding. As shown in Figures 14, 16, and 19, the motor housing 230, the rotor core 221, and the rotor magnets 222 are coaxially arranged. The rotor core 221 is secured to the motor housing 230. During processing, the rotor magnets 222 are secured to the rotor core 221 by a plastic member 227, such as a thermoplastic or thermosetting plastic. Specifically, the projection of the rotor magnets 222 along the axial direction of the motor 200 can be an inverted trapezoid, or other shape that makes it more difficult for the magnets 222 to fall out of the plastic member 227. The lower base of the inverted trapezoidal magnets 222 can be closer to the rotor core 221 than the upper base. In some embodiments, the motor housing 230 is made of aluminum and is mounted to the rotor core 221 by shrink-fitting. In some embodiments, a limiting boss 232 is further formed on the inner wall of the motor housing 230 for limiting the rotor core 221 in the axial direction, thereby enhancing the fixing effect of the motor housing 230 on the rotor core 221 .

[0174] In some embodiments, the motor 200 further includes a motor housing 230 and a fan 231 integrally formed with the motor housing 230. The fan 231 is disposed on the output shaft 226 of the motor 200 and is located on a plane perpendicular to the output shaft 226 of the motor 200. As shown in Figures 14 and 17, the fan 231 is integrally formed with the motor housing 230. The fan 231 is disposed on the output shaft 226 of the motor 200. The output shaft 226 of the motor 200 and the motor housing 230 can be interference-fitted to ensure a stable connection. Along the axial direction of the motor 200 from the non-output end to the output end, the motor housing 230 is sequentially provided with a fan 231, a limiting boss 232, a housing body, and a limiting boss 232. The rotor core 221 is supported and limited by the limiting boss 232 and is located within the housing body.

[0175] In some embodiments, the motor 200 also includes a bracket 250, and the stator 210, rotor 220, output shaft 226, support member 240 and bracket 250 are coaxially arranged. The stator 210, rotor 220, output shaft 226 and support member 240 can be sleeved or passed through the bracket 250. In this embodiment, the bracket 250 also forms or cooperates with the above-mentioned components to form an air inlet 2511 and an air outlet 2521 for heat dissipation airflow to pass through. Specifically, as shown in Figures 20 to 23, the bracket 250 may include a base 251 and a tube component 252. The base 251 is connected to the tube component 252 or formed as one piece. The plane where the base 251 is located may be basically perpendicular to the straight line where the tube component 252 is located. The base 251 is axially away from the fan 231. The tube component 252 can be provided for the above-mentioned stator 210, rotor 220, output shaft 226, and support member 240 to be sleeved or passed through. A radially or axially extending air inlet 2511 is provided on the bracket base 251, and the tube component 252 can form an axially extending air outlet 2521 with the output shaft 226 or support member 240 passing through it. The heat dissipation airflow will be blown in from the air inlet 2511, taking away the heat from the surface of the stator 210 and / or support member 240 attached to the bracket 250, and then blown out from the air outlet 2521.

[0176] In some embodiments, the support member 240 is connected to or integrally formed with the bracket 250. As shown in Figures 20 and 21, the support member 240, which has a rim and spoke structure, is disposed within the tubular component 252 of the bracket 250. The output shaft 226 is passed through the support member 240. The stator and rotor 210, 220 are sleeved outside the tubular component 252. The bracket 250 cooperates with the support member 240 to form an axially extending airflow channel to effectively dissipate heat from the stator 210, which is attached to the outer periphery of the bracket 250, and the support member 240 within the airflow channel. In other embodiments, as shown in Figures 22 and 23, the air inlet 2511 extends radially within the base 251. The tubular component 252 cooperates with the output shaft 226 passing therethrough to form an airflow channel. The air outlet 2521 extends axially between the tubular component 252 and the output shaft 226. The stator and rotor 210, 220, and the support member 240 can be sleeved outside the tubular component 252 of the bracket 250. In some other embodiments, the projections of the support member 240 and the bracket 250 in the axial direction of the motor 200 may partially overlap, and / or the projections of the two in the radial direction of the motor 200 may partially overlap or not overlap.

[0177] In some embodiments, the stator core 211 is provided with a plurality of radially extending teeth in the circumferential direction, the stator winding 212 is wound on the teeth, and the teeth of the stator core 211 have the characteristic of unequal width in the radial direction. As shown in FIG18 , the width W of the teeth of the stator core 211 is the width thereof in the direction perpendicular to its own extension. In some embodiments, the ratio of the maximum value to the minimum value of the width of the teeth unequal in the radial direction is greater than 1 and less than or equal to 1.8. As shown in FIG18 , the maximum value of the tooth width of the stator core 211 of the motor 200 is located at the tooth top, i.e., W1, and the minimum value of the tooth width is located at the tooth bottom, i.e., W2, and the ratio of the two is in the range of 1 to 1.8, wherein the tooth top is the end of the tooth away from the core yoke, and the tooth bottom is the end of the tooth close to the core yoke. Preferably, in some embodiments, the ratio of the maximum value to the minimum value of the tooth width is greater than 1 and less than or equal to 1.5.

[0178] In some embodiments, the stator windings 212 wound on different teeth of the stator core 211 are in phase or out of phase. Taking a three-phase motor as an example, the windings wound on several teeth can belong to the motor phase A, and the windings wound on several teeth can belong to the motor phase B. The specific winding order and connection relationship can be variable. In this embodiment, the number of turns of the two stator windings 212 belonging to the same phase can be different. The number of turns of the stator winding 212 is the number of wires wound in parallel on the tooth. In some embodiments, the motor 200 is a 10-pole 12-slot motor, the number of rotor magnets 222 is 10, and the number of teeth of the stator core 211 is 12. It can be understood that in other embodiments, the number of teeth of the rotor magnets 222 and the stator 210 can also be adjusted to adapt to the actual scenario.

[0179] The numerical settings of the above-mentioned parameters such as the outer diameter ratio of the stator and rotor 210, 220, the pole arc coefficient of the rotor 220, the tooth width of the stator core 211, and the number of turns of the stator winding 212 are intended to ensure the accurate and efficient operation of the high-power motor 200. Based on simulation and experiments, the relevant parameters can achieve the effects of increasing the slot fill rate, reducing the harmonic distortion rate, stabilizing torque fluctuations, and reducing motor noise.

[0180] In some embodiments, as shown in Tables 1 and 2 below, the power tools may be hair dryers, lawn trimmers, lawn mowers, and chainsaws. Hair dryers are high-speed power tools, chainsaws are medium-speed power tools, and grass trimmers and lawn mowers are low-speed power tools. The air gap ratio of the hair dryers, lawn trimmers, lawn mowers, and chainsaws is greater than or equal to 0.7. Alternatively, the air gap ratio may be greater than or equal to 0.8.

[0181] In some embodiments, the rated speed of the motor of the hair dryer is greater than or equal to 20,000 rpm. Alternatively, the rated speed of the motor can be 23,000 rpm. Alternatively, the rated speed of the motor can be 27,000 rpm. In some embodiments, the ratio of the rated power of the motor of the hair dryer to the volume of the stator is greater than or equal to 50 W / cm 3 Optionally, the ratio of the rated power of the motor to the volume of the stator can be 62.1W / cm 3 Optionally, the ratio of the rated power of the motor to the volume of the stator can be 75.8W / cm 3 .

[0182] In some embodiments, the rated speed of the motor of the chainsaw is greater than or equal to 10,000 rpm and less than or equal to 20,000 rpm. In some embodiments, the rated speed of the motor of the chainsaw is greater than or equal to 10,000 rpm and less than or equal to 17,000 rpm. Alternatively, the rated speed of the motor may be 11,000 rpm. Alternatively, the rated speed of the motor may be 11,500 rpm. In some embodiments, the ratio of the rated power of the motor of the chainsaw to the weight of the stator is greater than or equal to 6 W / g and less than or equal to 14 W / g. Alternatively, the ratio of the rated power of the motor to the weight of the stator is 6.5 W / g. Alternatively, the ratio of the rated power of the motor to the weight of the stator is 13.9 W / g.

[0183] Table 1

[0184] Table 2

[0185] The above shows and describes the basic principles, main features and advantages of this application. Those skilled in the art should understand that the above embodiments do not limit this application in any form, and any technical solutions obtained by equivalent replacement or equivalent transformation fall within the scope of protection of this application.

Claims

1. An electric tool, comprising: A motor, used to provide power for the electric tool, the motor comprising a stator and a rotor rotating relative to the stator, the rotor comprising a rotor core and a magnet disposed on the rotor core; a power supply device, electrically connected to at least the motor; an output portion, driven by the motor; The rotor core includes limiting portions spaced apart along the axis L, and the limiting portions are used to fix the magnetic steel.

2. The electric tool according to claim 1, wherein: The limiting portion includes a first limiting portion and a second limiting portion, wherein one of the first limiting portion and the second limiting portion is located at the head portion of the rotor core, and the other is located at the tail portion of the rotor core.

3. The electric tool according to claim 1, wherein: The limiting portion includes a first limiting portion and a second limiting portion, wherein one of the first limiting portion and the second limiting portion is located at the middle portion of the rotor core, and the other is located at the head and / or tail portion of the rotor core.

4. The electric tool according to claim 1, wherein: The limiting portion includes a first limiting portion, the thickness of the first limiting portion is in the range of 1mm-2mm; and / or The limiting portion includes a second limiting portion, and the thickness of the second limiting portion ranges from 1 mm to 2 mm.

5. The electric tool according to claim 1, wherein: The limiting portion forms a dovetail groove, and the magnetic steel is inserted into the dovetail groove along the axis L of the rotor core.

6. The electric tool according to claim 1, wherein: The limiting portion is lower than the magnetic steel in the circumferential direction.

7. The electric tool according to claim 1, wherein: The magnetic steel is fan-shaped, including an inner arc and an outer arc, the inner arc and the outer arc are concentrically arranged, and the distance between the center of the inner arc or the outer arc and the axis L of the rotor core is in the range of 50mm-100mm.

8. The electric tool according to claim 1, wherein: The rotor core includes a plurality of laminations stacked along an axis L, and the laminations are made of silicon steel.

9. The electric tool according to claim 1, wherein: The rotor further comprises a fastening sleeve, which is sleeved on the outer periphery of the rotor core, and the fastening sleeve has no magnetic conductivity.

10. The electric tool according to claim 1, wherein: The rotor further comprises a first fixing member, which is fixed to one end of the rotor core and is used to constrain the magnetic steel in the axial and circumferential directions.

11. The electric tool according to claim 1, wherein: The rotor further includes a second fixing member, wherein the second fixing member is fixed to the other end of the rotor core, and the second fixing member is used to radially constrain the magnetic steel.

12. The electric tool according to claim 1, wherein: The rated output power of the motor ranges from 3000W to 7000W.

13. The electric tool according to claim 1, wherein: The maximum speed range of the motor is greater than or equal to 20,000 rpm.

14. The electric power tool according to claim 1, wherein: The electric tool includes at least one of a chain saw, a snow blower, a pruner, a lawn mower, and a DC fan.

15. The electric power tool according to claim 1, wherein: The motor is an outer rotor motor.

16. An electric tool comprising: A motor, used to provide power for the electric tool, the motor comprising a stator and a rotor rotating relative to the stator and at least partially disposed outside the stator, the rotor comprising a rotor core and a magnet disposed on the rotor core; a power supply device, electrically connected to at least the motor; an output portion, driven by the motor; The rotor core includes a plurality of laminations arranged along the axis L, and the plurality of laminations have at least two different shapes so that the plurality of laminations at least include a first lamination having a first shape and a second lamination having a second shape.

17. The electric tool according to claim 16, wherein: The projection shape of the first laminate on the first plane is different from the projection shape of the second laminate on the first plane; the first plane is perpendicular to the output shaft.

18. An electric tool comprising: A motor, used to provide power for the electric tool, the motor comprising a stator and a rotor rotating relative to the stator, the rotor comprising a rotor core and a magnet disposed on the rotor core; a power supply device, electrically connected to at least the motor; an output portion, driven by the motor; A limiting portion for fixing the magnetic steel is formed on the inner wall of the rotor core, and the ratio of the total length of the limiting portion in the direction of the axis L to the length of the magnetic steel in the direction of the axis L is in the range of 0.01-0.

9.

19. The electric tool according to claim 18, wherein: The ratio of the total length of the limiting portion in the direction of the axis L to the length of the magnetic steel in the direction of the axis L is in the range of 0.1-0.

2.

20. The electric power tool according to claim 18, wherein: The number of the limiting parts is one or more.

21. A chain saw comprising: case; a saw chain and a guide plate, wherein the saw chain is arranged around the outer periphery of the guide plate, one end of the guide plate is supported by the housing, and the other end of the guide plate extends out of the housing along the longitudinal direction of the housing; A motor, used for driving the saw chain to perform cutting; The rated speed of the motor is greater than or equal to 10,000 rpm and less than or equal to 20,000 rpm, and the ratio of the rated power of the motor to the weight of the stator of the motor is greater than or equal to 6 W / g and less than or equal to 14 W / g.

22. The chain saw according to claim 21, wherein The rated speed of the motor is greater than or equal to 10,000 rpm and less than or equal to 17,000 rpm.

23. The chain saw of claim 21, wherein: The outer diameter ratio of the stator to the rotor is greater than or equal to 0.

7.

24. The chain saw of claim 21, wherein: The power density of the motor is greater than or equal to 2000 W / kg.

25. The chain saw of claim 21, wherein: A support member including a rim portion and a spoke portion is arranged at the radial center of the stator.

26. The chain saw of claim 21, wherein: The pole arc coefficient of the rotor of the motor is greater than or equal to 0.6 and less than 1.

27. The chain saw of claim 21, wherein: The stator comprises a stator core and a stator winding, wherein the stator core has a plurality of radially extending teeth, and the stator winding is wound on the teeth; the teeth have unequal widths in a radial direction, wherein the width of the teeth is the width of the teeth perpendicular to the extension direction thereof.

28. The chain saw of claim 27, wherein: A ratio of a maximum value to a minimum value of the width of the tooth is greater than 1 and less than or equal to 1.

8.

29. The chain saw of claim 21, wherein: The rotor of the motor comprises a rotor core and a magnetic steel, and the magnetic steel is fixed to the rotor core in a plastic-coated manner.

30. The chain saw of claim 25, wherein: The motor further comprises a bracket, the stator and the rotor are sleeved on the bracket, the support member is coaxially arranged with the bracket, and the bracket is formed with an air inlet and an air outlet for heat dissipation airflow to pass through.

31. The chain saw of claim 21, wherein: The motor further comprises a fan, and the motor further comprises a motor housing, wherein the motor housing and the fan are integrally formed.

32. The chain saw of claim 21, wherein: The rotor of the motor comprises a rotor core, and a limiting boss for limiting the rotor core in the axial direction is formed on the inner wall of the motor housing.

33. The chain saw of claim 25, wherein: The supporting member is made of metal or modified plastic.

34. The chain saw of claim 21, wherein: The rotor of the motor is sleeved outside the stator, and the support member is arranged inside the stator to support the stator.

35. The chain saw of claim 21, wherein: The rated output power of the motor ranges from 3000W to 7000W.

36. An electric tool comprising: case; Output section; and A motor is disposed in the housing, and the motor comprises: A stator, comprising a stator core and a stator winding; A rotor, including a rotor core and magnetic steel, is disposed on the periphery of the stator and is rotatable relative to the stator; and an output shaft coupled to the rotor to drive the output portion; The rated speed of the motor is greater than or equal to 20,000 rpm, and the ratio of the rated power of the motor to the volume of the stator is greater than or equal to 50 W / cm 3 .

37. The power tool according to claim 36, wherein: The electric tool is a hair dryer.

38. The power tool according to claim 36, wherein: The ratio of the outer diameters of the stator to the rotor is greater than or equal to 0.

7.

39. An electric tool comprising: case; Output section; and A motor is disposed in the housing, and the motor comprises: A stator, comprising a stator core and a stator winding; A rotor, including a rotor core and magnetic steel, is disposed on the periphery of the stator and is rotatable relative to the stator; and an output shaft coupled to the rotor to drive the output portion; The rated power of the motor is greater than or equal to 3000W and less than or equal to 7000W. The air gap ratio is greater than or equal to 0.

7.

40. The power tool according to claim 39, wherein: The outer diameter of the rotor is greater than or equal to 35 mm and less than or equal to 105 mm.

Images