WO2024088329A1 - 电动工具及适用于电动工具的马达 - Google Patents

电动工具及适用于电动工具的马达 Download PDF

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Publication number
WO2024088329A1
WO2024088329A1 PCT/CN2023/126652 CN2023126652W WO2024088329A1 WO 2024088329 A1 WO2024088329 A1 WO 2024088329A1 CN 2023126652 W CN2023126652 W CN 2023126652W WO 2024088329 A1 WO2024088329 A1 WO 2024088329A1
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WO
WIPO (PCT)
Prior art keywords
motor
electric tool
rotor core
magnetic
equal
Prior art date
Application number
PCT/CN2023/126652
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English (en)
French (fr)
Inventor
胡成龙
管建友
Original Assignee
南京泉峰科技有限公司
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Filing date
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Application filed by 南京泉峰科技有限公司 filed Critical 南京泉峰科技有限公司
Publication of WO2024088329A1 publication Critical patent/WO2024088329A1/zh

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Classifications

    • H—ELECTRICITY
    • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02K—DYNAMO-ELECTRIC MACHINES
    • H02K1/00—Details of the magnetic circuit
    • H02K1/06—Details of the magnetic circuit characterised by the shape, form or construction
    • H02K1/12—Stationary parts of the magnetic circuit
    • H02K1/14—Stator cores with salient poles
    • H—ELECTRICITY
    • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02K—DYNAMO-ELECTRIC MACHINES
    • H02K1/00—Details of the magnetic circuit
    • H02K1/06—Details of the magnetic circuit characterised by the shape, form or construction
    • H02K1/22—Rotating parts of the magnetic circuit
    • H02K1/27—Rotor cores with permanent magnets
    • H02K1/2706—Inner rotors
    • H02K1/272—Inner rotors the magnetisation axis of the magnets being perpendicular to the rotor axis
    • H02K1/274—Inner rotors the magnetisation axis of the magnets being perpendicular to the rotor axis the rotor consisting of two or more circumferentially positioned magnets
    • H02K1/2753—Inner rotors the magnetisation axis of the magnets being perpendicular to the rotor axis the rotor consisting of two or more circumferentially positioned magnets the rotor consisting of magnets or groups of magnets arranged with alternating polarity
    • H02K1/276—Magnets embedded in the magnetic core, e.g. interior permanent magnets [IPM]

Definitions

  • the present application relates to an electric tool, for example, to a motor suitable for the electric tool.
  • the electric tools in the related art are generally mechanized tools that use motors as power and drive the working head through a transmission mechanism to perform operations.
  • the motors used in the electric tools are generally permanent magnet brushless DC motors, and permanent magnet brushless DC motors all use rare earth magnets.
  • the motors used in the electric tool field are all four-magnet motors.
  • One object of the present application is to solve or at least alleviate part or all of the above problems. To this end, one object of the present application is to provide a motor suitable for an electric tool, which can effectively reduce the cost of the electric tool.
  • an electric tool comprising: a motor for providing power to the electric tool; the motor comprises a stator and a rotor rotating relative to the stator; a power supply device for providing electrical energy to the motor; the rotor comprises a rotor core and magnets arranged on the rotor core; the number of magnets is two, and the two magnets can form four magnetic poles.
  • the split ratio of the motor is less than or equal to 0.5.
  • two magnetic steel slots are provided on the rotor core, and the two magnetic steel slots are symmetrically arranged relative to the center hole of the rotor core, and the two magnets are respectively arranged in the two magnetic steel slots.
  • the ratio of the length of the magnetic steel slot to the outer diameter of the rotor core is greater than or equal to 0.5.
  • the outer diameter of the rotor core is less than or equal to 40 mm.
  • the narrowest part between the magnetic steel slot and the outer circle of the rotor core is the magnetic isolation bridge, and the width of the magnetic isolation bridge is less than or equal to 1 mm.
  • the stator includes a stator core, which is disposed outside the rotor core.
  • the interval between the stator core and the rotor core is an air gap, and the width of the air gap is less than or equal to 1 mm.
  • the air gap is a uniform air gap or a non-uniform air gap.
  • the width of the air gap at its narrowest point is less than or equal to 1 mm.
  • the outer surface of the rotor core has two mounting planes, and the two mounting planes are symmetrically arranged relative to the central hole of the rotor core, and the two magnets are respectively attached to the two mounting planes.
  • the output power of the motor is less than or equal to 500W.
  • the power supply includes at least one rechargeable battery pack.
  • the battery pack includes a tool coupling portion
  • the electric tool includes a battery coupling portion adapted to the tool coupling portion; the tool coupling portion is detachably connected to the battery coupling portion.
  • the motor comprises a brushless DC motor.
  • the power tool comprises a handheld power tool.
  • an electric tool comprising: a motor for providing power to the electric tool, the motor comprising a stator and a rotor rotating relative to the stator; a power supply device for providing electrical energy to the motor; the rotor comprising a rotor core and magnets arranged on the rotor core; the number of magnets is two; the output power of the motor is less than or equal to 500W.
  • the split ratio of the motor is less than or equal to 0.5.
  • the outer diameter of the rotor core is less than or equal to 40 mm.
  • a motor suitable for a handheld power tool includes: the motor includes a stator and a rotor rotating relative to the stator; the rotor includes a rotor core and magnets arranged on the rotor core; the number of the magnets is two; and the two magnets can form four magnetic poles.
  • the motor comprises a brushless DC motor.
  • the handheld power tool includes an electric drill, a screwdriver, a wrench, a circular saw, an angle grinder, and a reciprocating saw.
  • FIG1 is a schematic structural diagram of an electric tool according to an embodiment of the present application.
  • FIG2 is a schematic diagram of the exploded structure of an embodiment of the present application.
  • FIG3 is a schematic structural diagram of a stator core and a rotor core according to an embodiment of the present application
  • FIG4 is a schematic diagram of magnetic force line distribution according to an embodiment of the present application.
  • FIG5 is a schematic diagram of the exploded structure of a rotor according to an embodiment of the present application.
  • FIG6 is a schematic structural diagram of a stator core and a rotor core according to an embodiment of the present application.
  • FIG7 is a schematic structural diagram of a stator core and a rotor core according to an embodiment of the present application.
  • FIG8 is a schematic structural diagram of a rotor according to an embodiment of the present application.
  • FIG9 is a schematic diagram of magnetic force line distribution according to an embodiment of the present application.
  • FIG. 10 is a performance comparison analysis diagram of an embodiment of the present application.
  • the term "and/or” is a description of the association relationship between related objects, indicating that three relationships can exist.
  • a and/or B can represent: A exists alone, A and B exist at the same time, and B exists alone.
  • the character "/" in this application generally indicates that the related objects before and after are in an "and/or” relationship.
  • connection may refer to direct connection, combination, coupling, or installation, or indirect connection, combination, coupling, or installation.
  • direct connection refers to two parts or components being connected together without the need for an intermediate piece
  • indirect connection refers to two parts or components being connected to at least one intermediate piece respectively, and the two parts or components being connected via the intermediate piece.
  • connect and “couple” are not limited to physical or mechanical connection or coupling, and may include electrical connection or coupling.
  • relative terms e.g., "about,” “approximately,” “substantially,” etc.
  • the relative terms include at least the degree of error associated with the measurement of a specific value, the tolerances caused by manufacturing, assembly, and use associated with a specific value, and the like. 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.
  • 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).
  • controller In this application, the terms “controller”, “processor”, “central processing unit”, “CPU”, and “MCU” are interchangeable. When a unit “controller”, “processor”, “central processing unit”, “CPU”, or “MCU” is used to perform a specific function, unless otherwise specified, these functions can be performed by a single unit or multiple units.
  • the terms “device”, “module” or “unit” may be implemented in the form of hardware or software to achieve specific functions.
  • the terms “calculate”, “judge”, “control”, “determine”, “identify”, etc. refer to the operations and processes of a computer system or similar electronic computing device (e.g., controller, processor, etc.).
  • FIG1 shows a specific embodiment of the present application as an electric tool, such as an electric drill.
  • the motor 30 taught in the present application can be applied to handheld electric tools such as electric drills, impact drills, electric wrenches, electric screwdrivers, electric hammer drills, electric circular saws, sanders, table tools such as table saws, and outdoor tools such as lawn mowers, snow blowers, lawn mowers, electric shears, pruning machines, and chain saws.
  • handheld electric tools such as electric drills, impact drills, electric wrenches, electric screwdrivers, electric hammer drills, electric circular saws, sanders, table tools such as table saws, and outdoor tools such as lawn mowers, snow blowers, lawn mowers, electric shears, pruning machines, and chain saws.
  • the following embodiments are part of the present application. Examples, not all embodiments.
  • the power tool 100 is used to output torque, and includes: a housing 10, a motor 30, a transmission assembly, and an output shaft 20.
  • the housing 10 accommodates the motor 30 and the transmission assembly, and supports the output shaft 20.
  • the motor 30 is used to drive the output shaft 20 to rotate about the first axis, and the transmission assembly connects the motor 30 and the output shaft 20, thereby transmitting the output of the motor 30 to the output shaft 20.
  • the power tool 100 also includes a chuck device for clamping a tool accessory such as a drill bit, and the chuck device is connected to the output shaft 20, thereby driving the tool accessory to output.
  • the housing 10 includes a head shell 11 and a grip portion 12, and the motor 30 and the transmission assembly are arranged in the head shell 11.
  • the grip portion 12 is connected to the head shell 11 for the user to hold.
  • the head shell 11 and the grip portion 12 are connected in an L-shape or a T-shape to facilitate the user to hold and operate.
  • the power tool 100 also includes a power supply device 40, which can be a battery pack or a mains power connector, and the power supply device 40 is configured to be connected to the housing 10.
  • the power supply device includes at least one rechargeable battery pack 41.
  • the battery pack 41 is detachably connected to the power tool 100.
  • the battery pack 41 includes a tool coupling portion 411
  • the power tool 100 includes a battery coupling portion 13 adapted to the tool coupling portion 411.
  • the tool coupling portion 411 is detachably connected to the battery coupling portion 13.
  • the motor 30 provided in the present application is adapted to the electric tool, so its output power is less than or equal to 500 W to meet the working requirements of the electric tool.
  • the motor 30 is a permanent magnet brushless DC motor.
  • the motor 30 includes a stator and a rotor that rotates relative to the stator.
  • the stator includes a stator core 31 and an excitation winding wound on the teeth of the stator core 31.
  • the function of the stator is to generate an excitation flux.
  • the rotor includes a rotor core 32 and a magnet 33 arranged on the rotor core 32.
  • the function of the rotor is to generate an electromagnetic torque.
  • a rotating shaft 34 is arranged in the center hole 322 of the rotor core 32.
  • the rotor outputs torque through the rotating shaft 34 to convert electrical energy into mechanical energy.
  • This embodiment adopts an inner rotor motor, that is, the rotor core 32 is located on the inner side of the stator core 31.
  • the stator core 31 and the rotor core 32 are usually made of an appropriate number of A stack of metal laminations is formed by axially stacking a large number of metal laminations together by riveting or welding.
  • the main component of the metal laminations is iron, so it is called an iron core, specifically a magnetic silicon steel sheet.
  • the stator and the rotor are closed by the lower end cover 36 and the upper end cover 37.
  • the stator core 31 can be a split stator or an integral stator. When it is an integral stator, each layer of laminations in the axial direction is hollow and integral, rather than being spliced together by multiple small laminations.
  • the thickness of a single metal lamination is constant, and the axial length of the stator core is the total thickness of an appropriate number of laminations stacked together.
  • the outer contour of the integral stator can be set to a circular, elliptical, flat square or other shape suitable for being accommodated in the outer shell 35.
  • the number of magnetic steels 33 is four, and four magnetic steel slots 321 are provided on the rotor core 32, and the four magnetic steel slots 321 are evenly distributed around the center hole 322 of the rotor core 32, and the four magnetic steels 33 are respectively arranged in the four magnetic steel slots 321 in a one-to-one correspondence.
  • the four magnetic steels 33 form four magnetic poles, including two N poles and two S poles. Due to the large number of magnetic steels 33 used, the overall structural size of the motor 30 is large.
  • the outer diameter of the rotor core 32 is 21 mm, and the ratio of the outer diameter of the rotor core 32 to the outer diameter of the stator core 31 is equal to 0.525.
  • the narrowest part between the magnetic steel slot 321 and the outer circle of the rotor core 32 is the magnetic isolation bridge.
  • the width of the magnetic isolation bridge is generally less than or equal to 1 mm. In the structure of the related art, the width of the magnetic isolation bridge is 0.6 mm.
  • the length of the magnetic steel slot 321 is equal to 11 mm, and the ratio of the length of the magnetic steel slot 321 to the outer diameter of the rotor is equal to 0.5238.
  • the number of magnets 33 is two. Since the magnetic permeability of the rotor core 32 is relatively high, two virtual magnetic poles are formed between the two magnets 33. Referring to Figure 9, two real N poles and two virtual S poles, that is, two magnets 33 can also generate four magnetic poles, which not only ensures the working performance of the power tool, but also reduces the amount of magnets 33, effectively reducing the cost of the power tool; and since the amount of magnets 33 is reduced, the iron loss is also reduced.
  • FIG10 shows a comparative analysis of the performance of a four-magnet motor in the related art and a two-magnet motor in the present application.
  • the figure includes four curves, wherein the curve ⁇ ' represents the efficiency curve of the four-magnet motor, ⁇ represents the efficiency curve of the two-magnet motor, v' represents the speed curve of the four-magnet motor, and v represents the speed curve of the two-magnet motor.
  • the efficiency and speed of the two-magnet motor are better than those of the four-magnet motor; under heavy loads, the efficiency and speed of the two-magnet motor are basically the same as those of the four-magnet motor. That is, the performance of the two-magnet motor in the light and medium load areas is better, and can ensure the working performance of the power tool.
  • two magnetic steel slots 321 are provided on the rotor core 32, and the two magnetic steel slots 321 are symmetrically arranged relative to the center hole 322 of the rotor core 32, and the two magnetic steels 33 are respectively arranged in the two magnetic steel slots 321 in a one-to-one correspondence. That is, Figures 6 and 7 show an implementation method in which the magnetic steel 33 is built-in. In other embodiments, referring to Figure 8, the magnetic steel 33 can also be attached to the outer surface of the rotor core 32, that is, the magnetic steel 33 is externally placed.
  • the outer surface of the rotor core 32 has two mounting planes, and the two mounting planes are symmetrically arranged relative to the center hole 322 of the rotor core 32, and the two magnetic steels 33 are respectively attached to the two mounting planes in a one-to-one correspondence.
  • the split ratio (ratio of the inner diameter to the outer diameter of the stator core 31) of the motor 30 is less than or equal to 0.5.
  • the outer diameter D1 of the stator core 31 is less than or equal to 80 mm, and in particular, the outer diameter of the stator core 31 is less than or equal to 52 mm.
  • the outer diameter D1 of the stator core 31 can be 40 mm.
  • the outer diameter D1 of the stator core 31 is equal to 40 mm
  • the outer diameter D2 of the rotor core 32 is equal to 18.4 mm
  • the ratio of the outer diameter D2 of the rotor core 32 to the outer diameter D1 of the stator core 31 is equal to 0.46.
  • the overall size of the motor 30 is smaller, which reduces the space occupied in the power tool, thereby facilitating the miniaturization design of the power tool and making it easier for the user to operate.
  • the position indicated by arrow A in Figures 6 and 7 is the magnetic isolation bridge, which is formed between the steel slot and the outer circle of the rotor core.
  • a very narrow channel is used as a magnetic isolation bridge.
  • the width W1 of the magnetic isolation bridge is 0.45 mm.
  • the length L1 of the magnetic steel slot 321 is equal to 11.3 mm, and the ratio D2 of the length L1 of the magnetic steel slot 321 to the outer diameter of the rotor is greater than or equal to 0.6.
  • the length of the magnetic steel slot 321 is increased, so that a slightly larger magnetic steel 33 can be configured to improve the performance of the rotor.
  • the gap (air gap) between the inner diameter of the stator core 31 and the outer diameter of the rotor core 32 is uniform along the circumferential direction, and the air gap width W2 is less than or equal to 1 mm, specifically 0.5 mm.
  • the gap (air gap) between the inner diameter of the stator core 31 and the outer diameter of the rotor core 32 is non-uniform along the circumferential direction, and the minimum air gap width W3 is 0.5 mm.

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  • Engineering & Computer Science (AREA)
  • Power Engineering (AREA)
  • Iron Core Of Rotating Electric Machines (AREA)

Abstract

本申请涉及一种电动工具，包括马达和供电装置，马达用于为电动工具提供动力，马达包括定子和相对定子旋转的转子，转子包括转子铁芯和设置于转子铁芯上的磁钢；供电装置至少与马达电连接；磁钢的数量为两个，两个磁钢能够形成四个磁极。采用以上技术方案能够提供一种马达输出性能稳定且磁钢数量少成本低的电动工具。

Description

电动工具及适用于电动工具的马达
本申请要求在2022年10月27日提交中国专利局、申请号为202211328165.2的中国专利申请的优先权，该申请的全部内容通过引用结合在本申请中。
技术领域
本申请涉及一种电动工具，例如涉及一种适用于电动工具的马达。
背景技术
相关技术中的电动工具一般是以马达作为动力，通过传动机构驱动工作头进行作业的一种机械化工具。电动工具中所用的马达一般为永磁无刷直流电机，而永磁无刷直流电机均采用稀土磁钢。在相关技术中，电动工具领域所采用的电机均为四磁钢电机。
本部分提供了与本申请相关的背景信息，这些背景信息不一定是现有技术。
发明内容
本申请的一个目的是解决或至少减轻上述问题的一部分或者全部。为此，本申请的一个目的在于提供一种适用于电动工具的马达，能有效降低电动工具的成本。
本申请采用以下技术方案：一种电动工具，包括：马达，用于为电动工具提供动力；马达包括定子和相对定子旋转的转子；供电装置，用于为马达提供电能；转子包括转子铁芯和设置于转子铁芯上的磁钢；磁钢的数量为两个，两个磁钢能够形成四个磁极。
在一些实施例中，马达的裂比小于等于0.5。
在一些实施例中，转子铁芯上设置有两个磁钢槽，且两个磁钢槽相对于转子铁芯的中心孔对称设置，两个磁钢分别对应设置于两个磁钢槽内。
在一些实施例中，磁钢槽的长度与转子铁芯的外径之比大于等于0.5。
在一些实施例中，转子铁芯的外径小于等于40mm。
在一些实施例中，磁钢槽与转子铁芯的外圆之间最窄的部分为隔磁桥，隔磁桥的宽度小于等于1mm。
在一些实施例中，定子包括定子铁芯，定子铁芯设置于转子铁芯的外侧，定子铁芯与转子铁芯之间的间隔为气隙，气隙的宽度小于等于1mm。
在一些实施例中，气隙为均匀气隙或不均匀气隙，当气隙为不均匀气隙时，气隙的最窄处的宽度小于等于1mm。
在一些实施例中，转子铁芯的外表面具有两个安装平面，且两个安装平面相对于转子铁芯的中心孔对称设置，两个磁钢分别对应的贴附于两个安装平面。
在一些实施例中，马达的输出功率小于或等于500W。
在一些实施例中，供电装置包括至少一个可充电的电池包。
在一些实施例中，电池包包括工具结合部，电动工具包括与工具结合部适配的电池结合部；工具结合部可拆卸地连接至电池结合部。
在一些实施例中，马达包括无刷直流电机。
在一些实施例中，电动工具包括手持式电动工具。
为达此目的，本申请采用以下技术方案：一种电动工具，包括：马达，用于为电动工具提供动力，马达包括定子和相对定子旋转的转子；供电装置，用于为马达提供电能；转子包括转子铁芯和设置于转子铁芯上的磁钢；磁钢的数量为两个；马达的输出功率小于等于500W。
在一些实施例中，马达的裂比小于等于0.5。
在一些实施例中，转子铁芯的外径小于等于40mm。
为达此目的，本申请采用以下技术方案：一种适用于手持电动工具的马达， 马达包括：马达包括定子和相对定子旋转的转子；转子包括转子铁芯和设置于转子铁芯上的磁钢；磁钢的数量为两个；两个磁钢能够形成四个磁极。
在一些实施例中，马达包括无刷直流电机。
在一些实施例中，手持电动工具包括电钻、螺丝批、扳手、圆锯、角磨、往复锯。
附图说明
图1是本申请的一个实施例的电动工具的结构示意图；
图2是本申请的一个实施例的分解结构示意图；
图3是本申请的一个实施例的定子铁芯和转子铁芯的结构示意图；
图4是本申请的一个实施例的磁力线分布示意图；
图5是本申请的一个实施例的转子的分解结构示意图；
图6是本申请的一个实施例的定子铁芯和转子铁芯的结构示意图；
图7是本申请的一个实施例的定子铁芯和转子铁芯的结构示意图；
图8是本申请的一个实施例的转子的结构示意图；
图9是本申请的一个实施例的磁力线分布示意图；
图10是本申请的一个实施例的性能对比分析图。
具体实施方式
在详细解释本申请的任何实施方式之前，应当理解，本申请不限于其应用到以下描述中阐述的或以上附图中所示的结构细节和组件布置。
在本申请中，术语“包括”、“包含”、“具有”或者其任何其他变体意在涵盖非排他性的包含，从而使得包括一系列要素的过程、方法、物品或者装置不仅包括那些要素，而且还包括没有明确列出的其他要素，或者是还包括为 这种过程、方法、物品或者装置所固有的要素。在没有更多限制的情况下，由语句“包括一个……”限定的要素，并不排除在包括该要素的过程、方法、物品或者装置中还存在另外的相同要素。
在本申请中，术语“和/或”，是一种描述关联对象的关联关系，表示可以存在三种关系。例如，A和/或B，可以表示：单独存在A，同时存在A和B，单独存在B这三种情况。另外，本申请中字符“/”，一般表示前后关联对象是一种“和/或”的关系。
本申请中，术语“连接”、“结合”、“耦合”、“安装”可以是直接连接、结合、耦合或安装，也可以是间接连接、结合、耦合或安装。其中，进行举例示范，直接连接指的是两个零件或组件之间不需设置中间件而连接在一起，间接连接指的是两个零件或组件分别与至少一个中间件连接，这两个零件或组件通过中间件实现连接。此外，“连接”和“耦合”不限于物理或机械连接或耦合，并且可以包括电连接或耦合。
在本申请中，本领域普通技术人员将理解，结合数量或条件使用的相对术语(例如，“约”，“大约”，“基本”等)为包括所述值并且具有上下文所指示的含义。例如，该相对术语至少包括与特定值的测量相关的误差程度，与特定值相关的由制造，组装，使用造成的公差等。这种术语也应被视为公开了由两个端点的绝对值限定的范围。相对术语可指代所指示的值的一定百分比(例如1％，5％，10％或更多)的加或减。未采用相对术语的数值，也应该被揭示为具有公差的特定值。此外，“基本”在表达相对的角度位置关系时(例如，基本平行，基本垂直)，可指代在所指示的角度的基础上加或减一定度数(例如1度，5度，10度或更多)。
在本申请中，本领域普通技术人员将理解，由组件执行的功能可以为由一 个组件，多个组件，一个零件，或多个零件执行。同样的，由零件执行的功能也可以由一个零件，一个组件，或多个零件组合来执行。
在本申请中，术语“上”、“下”、“左”、“右”、“前”、“后”等方位词是以附图所示的方位和位置关系来进行描述的，不应理解为对本申请实施例的限定。此外，在上下文中，还需要理解的是，当提到一个元件连接在另一个元件“上”或者“下”时，其不仅能够直接连接在另一个元件“上”或者“下”，也可以通过中间元件间接连接在另一个元件“上”或者“下”。还应当理解的，上侧、下侧、左侧、右侧、前侧、后侧等方位词不仅代表正方位，也可以理解为侧方位。例如，下方可以包括正下方、左下方、右下方、前下方以及后下方等。
在本申请中，术语“控制器”、“处理器”、“中央处理器”、“CPU”、“MCU”可以互换。在使用单元“控制器”、“处理器”、“中央处理器”、“CPU”、或“MCU”来执行特定功能，除非另有说明，否则这些功能则可以由单个上述单元或多个上述单元来执行。
在本申请中，术语“装置”、“模块”或“单元”为了实现特定的功能，它们可以通过硬件或软件的形式来实现。
在本申请中，术语“计算”、“判断”、“控制”、“确定”、“识别”等指的是计算机系统或类似电子计算设备(例如，控制器，处理器等)的操作和过程。
图1示出了本申请作为电动工具的具体实施例，如电钻。实际上本申请所教导的马达30可适用于电钻、冲击钻、电动扳手、电动螺丝批、电锤钻、电圆锯、砂光机等手持式电动工具，台锯等台型工具以及割草机、扫雪机、打草机、电剪刀、修枝机、链锯等户外工具。显然，以下的实施例是本申请一部分实施 例，而不是全部的实施例。
参照图1和图2所示，电动工具100用于输出扭力，其包括：壳体10、马达30、传动组件以及输出轴20。壳体10容纳马达30和传动组件，且支撑输出轴20。马达30用于驱动输出轴20以第一轴线为轴转动，传动组件连接马达30和输出轴20，从而将马达30的输出传递至输出轴20。电动工具100还包括夹头装置，用于夹持工具附件如钻头，夹头装置连接到输出轴20，从而带动工具附件输出。
壳体10包括头壳11和握持部12，马达30和传动组件被设置在头壳11内。握持部12连接头壳11供用户握持。头壳11和握持部12呈L型或T型连接，以方便用户握持操作。电动工具100还包括供电装置40，供电装置40可以是电池包或者市电连接器，供电装置40被设置连接于壳体10。在一些实施例中，供电装置包括至少一个可充电的电池包41。在一些实施例中，电池包41可拆卸地连接至电动工具100。具体地，电池包41包括工具结合部411，电动工具100包括与工具结合部411适配的电池结合部13。工具结合部411可拆卸地连接至电池结合部13。
本申请所提供的马达30因适配于电动工具，故其输出功率小于等于500W即可满足电动工具的工作需求。本实施例中，马达30为永磁无刷直流电机。
参见图2和图3所示，马达30包括定子和相对定子旋转的转子。定子包括定子铁芯31和缠绕于定子铁芯31的齿部上的激磁绕组，定子的作用是产生激磁磁通。转子包括转子铁芯32和设置于转子铁芯32上的磁钢33，转子的作用是产生电磁转矩。转子铁芯32的中心孔322中设置有转轴34，转子通过转轴34输出转矩，将电能转换为机械能。本实施例采用的是内转子式马达，即转子铁芯32位于定子铁芯31的内侧。定子铁芯31和转子铁芯32通常是用适当数 量的金属叠片沿轴向堆在一起并通过铆接或焊接而形成的叠片堆，金属叠片的主要成分是铁，所以称为铁芯，具体为导磁硅钢片。定子和转子通过下端盖36和上端盖37进行封闭。另外定子铁芯31可以是分体式定子或整体式定子，当为整体式定子时，其在轴向上的每一层叠片都是中空的整体的，而不是由多个小叠片拼接成的。通常单个金属叠片的厚度一定，定子铁芯的轴向长度就是适当数量的叠片堆起来的总厚度。整体式定子的外轮廓可以设置成圆形、椭圆形、扁方形或者其他形状适合收容在外壳35中的形状。
相关技术中，参照图3所示，磁钢33的数量为四个，转子铁芯32上设置有四个磁钢槽321，且四个磁钢槽321环绕转子铁芯32的中心孔322均匀分布，四个磁钢33分别一一对应的设置于四个磁钢槽321内。参照图4所示，四个磁钢33形成四个磁极，包括两个N极和两个S极。由于采用的磁钢33数量较多，导致马达30的整体结构尺寸较大。具体的，转子铁芯32的外径为21mm，转子铁芯32的外径与定子铁芯31的外径之比等于0.525。磁钢槽321与转子铁芯32的外圆之间最窄的部分为隔磁桥，一般隔磁桥宽度越小，磁桥部位磁通越饱和，限制漏磁效果越好。但是其宽度不能过小，否则将使冲片机械强度变差，缩短冲模的使用寿命。隔磁桥的宽度一般小于等于1mm，相关技术的结构中，隔磁桥宽度为0.6mm。磁钢槽321长度等于11mm，磁钢槽321长度与转子外径比等于0.5238。
本实施例中，参照图5至图8所示，磁钢33的数量为两个，由于转子铁芯32的导磁率较高，故会在两个磁钢33之间形成两个虚拟的磁极，参照图9，包括两个真实的N极和两个虚拟的S极，即两个磁钢33也能产生四个磁极，既保证了电动工具的工作性能，又减少了磁钢33用量，有效降低了电动工具的成本；并且由于减少了磁钢33用量，还降低了铁损。
图10示出的是相关技术四磁钢马达与本申请两磁钢马达的性能对比分析，图中包括四条曲线，曲线η’代表四磁钢马达的效率曲线，η代表两磁钢马达的效率曲线，v’代表四磁钢马达的速度曲线，v代表两磁钢马达的速度曲线。在轻载和中载时，即力矩小于等15N·cm时，两磁钢马达的效率和转速均优于四磁钢马达；在重载时，两磁钢马达的效率和速度与四磁钢马达基本持平。即两磁钢马达在轻载和中载区域的性能较好，能够保证电动工具的工作性能。
本实施例中，参照图6和图7，在转子铁芯32上设置有两个磁钢槽321，且两个磁钢槽321相对于转子铁芯32的中心孔322对称设置，两个磁钢33分别一一对应的设置于两个磁钢槽321内。即图6和图7示出的是磁钢33内置的实施方式。在其他实施例中，参照图8，磁钢33还能够贴附于转子铁芯32的外表面，即磁钢33外置。具体地，转子铁芯32的外表面具有两个安装平面，且两个安装平面相对于转子铁芯32的中心孔322对称设置，两个磁钢33分别一一对应的贴附于两个安装平面。
本实施例中，由于磁钢33数量减小，故马达30的整体结构尺寸得到了优化。具体地，马达30的裂比(定子铁芯31的内径与外径的比值)小于等于0.5。本实施例中，参见图6所示，定子铁芯31的外径D1小于等于80mm，尤其，定子铁芯31的外径的小于等于52mm，当应用于电钻中时，定子铁芯31的外径D1可以为40mm。
本实施例中，定子铁芯31外径D1等于40mm，转子铁芯32外径D2等于18.4mm，转子铁芯32外径D2与定子铁芯31外径D1比等于0.46。相比于相关技术，马达30的整体尺寸更小，减少了在电动工具中的占用空间，从而有利于电动工具的小型化设计，进而更加便于使用者进行操作。
图6和图7中箭头A所指的位置为隔磁桥，钢槽跟转子铁芯外圆之间形成 一条很窄的通道作为隔磁桥本实施例中，隔磁桥的宽度W1为0.45mm。相比于相关技术，隔磁桥的宽度有所降低，磁桥部位磁通更加饱和，限制漏磁效果更优。磁钢槽321长度L1等于11.3mm，磁钢槽321长度L1与转子外径比D2大于等于0.6。相比于相关技术，磁钢槽321长度有所增长，从而可以配置稍大规格的磁钢33，以提高转子的性能。
本实施例中，参照图6，定子铁芯31内径和转子铁芯32外径的间隙(气隙)沿圆周方向是均匀的，气隙宽度W2小于等于1mm，具体为0.5mm。或者参照图7，定子铁芯31内径和转子铁芯32外径的间隙(气隙)沿圆周方向是不均匀的，最小气隙宽度W3是0.5mm。
以上显示和描述了本申请的基本原理、主要特征和优点。本行业的技术人员应该了解，上述实施例不以任何形式限制本申请，凡采用等同替换或等效变换的方式所获得的技术方案，均落在本申请的保护范围内。

Claims (20)

  1. 一种电动工具，包括：
    马达，用于为所述电动工具提供动力；所述马达包括定子和相对所述定子旋转的转子；
    供电装置，用于为所述马达提供电能；
    其中，
    所述转子包括转子铁芯和设置于所述转子铁芯上的磁钢；
    所述磁钢的数量为两个，两个所述磁钢能够形成四个磁极。
  2. 根据权利要求1所述的电动工具，其中，所述马达的裂比小于等于0.5。
  3. 根据权利要求1所述的电动工具，其中，所述转子铁芯上设置有两个磁钢槽，且两个所述磁钢槽相对于所述转子铁芯的中心孔对称设置，两个所述磁钢分别对应设置于两个所述磁钢槽内。
  4. 根据权利要求3所述的电动工具，其中，所述磁钢槽的长度与所述转子铁芯的外径之比大于等于0.5。
  5. 根据权利要求1所述的电动工具，其中，所述转子铁芯的外径小于等于40mm。
  6. 根据权利要求3所述的电动工具，其中，所述磁钢槽与所述转子铁芯的外圆之间最窄的部分为隔磁桥，所述隔磁桥的宽度W1小于等于1mm。
  7. 根据权利要求3所述的电动工具，其中，所述定子包括定子铁芯，所述定子铁芯设置于所述转子铁芯的外侧，所述定子铁芯与所述转子铁芯之间的间隔为气隙，所述气隙的宽度W2小于等于1mm。
  8. 根据权利要求7所述的电动工具，其中，所述气隙为均匀气隙或不均匀气隙，当所述气隙为不均匀气隙时，所述气隙的最窄处的宽度W3小于等于1mm。
  9. 根据权利要求3所述的电动工具，其中，所述磁钢槽长度L1与转子外径 比D2大于等于0.6。
  10. 根据权利要求1所述的电动工具，其中，所述马达的输出功率小于或等于500W。
  11. 根据权利要求1所述的电动工具，其中，所述供电装置包括至少一个可充电的电池包。
  12. 根据权利要求11所述的电动工具，其中，所述电池包包括工具结合部，所述电动工具包括与所述工具结合部适配的电池结合部；所述工具结合部可拆卸地连接至所述电池结合部。
  13. 根据权利要求1所述的电动工具，其中，所述马达包括无刷直流电机。
  14. 根据权利要求1所述的电动工具，其中，所述电动工具包括手持式电动工具。
  15. 一种电动工具，包括：
    马达，用于为所述电动工具提供动力，所述马达包括定子和相对所述定子旋转的转子；
    供电装置，用于为所述马达提供电能；
    其中，
    所述转子包括转子铁芯和设置于所述转子铁芯上的磁钢；
    所述磁钢的数量为两个；
    所述马达的输出功率小于等于500W。
  16. 根据权利要求15所述的电动工具，其中，所述马达的裂比小于等于0.5。
  17. 根据权利要求15所述的电动工具，其中，所述转子铁芯的外径小于等于40mm。
  18. 一种适用于电动工具的马达，所述马达包括：
    定子和相对所述定子旋转的转子；
    所述转子包括转子铁芯和设置于所述转子铁芯上的磁钢；
    所述磁钢的数量为两个；两个所述磁钢能够形成四个磁极。
  19. 根据权利要求18所述的马达，其中，所述马达包括无刷直流电机。
  20. 根据权利要求18所述的马达，其中，所述电动工具包括电钻、螺丝批、扳手、圆锯、角磨、往复锯。
PCT/CN2023/126652 2022-10-27 2023-10-26 电动工具及适用于电动工具的马达 WO2024088329A1 (zh)

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CN217063416U (zh) * 2021-12-22 2022-07-26 深圳绿威科技有限公司 一种无刷电机及电动工具

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