Fan motor and vacuum cleaner using same

Abstract

A vacuum cleaner according to one aspect of the present disclosure may comprise a suction fan and a dust collector. The suction fan may include a fan motor and an impeller. The fan motor may include a shaft, a rotor fixed to the shaft, and a stator. The stator may include an annular core ring, a plurality of protruding teeth protruding from the core ring toward a rotational axis and arranged radially, and a plurality of coils arranged on each of the plurality of teeth. Each of the plurality of teeth may include a protruding end opposing the rotor with an air gap, a first flange portion protruding from the protruding end in the rotational direction, and a second flange portion protruding in a direction opposite to a rotational direction. The first flange portion and the second flange portion may be asymmetrical with respect to a center line of the teeth extending from the rotational axis.

Description

Fan motor and vacuum cleaner using it

[0001] The present disclosure relates to a fan motor and a vacuum cleaner employing the same.

[0002] Compact, lightweight, cordless, easy-to-handle stick vacuums and robotic vacuums are being developed. These compact, lightweight vacuums are equipped with a suction fan (mini fan) equipped with a small impeller measuring 3-5 cm in diameter. To generate high suction power with the mini fan, the fan motor that rotates the impeller must be compact and lightweight, capable of rotating at over 50,000 rpm (revolutions per minute) while ensuring adequate torque.

[0003] Even in compact, lightweight vacuum cleaners, high suction power comparable to or higher than that of conventional canister-type vacuum cleaners is required. Therefore, fan motors are becoming increasingly faster, and recently, motors capable of exceeding 100,000 rpm have become available. Fan motors used in compact, lightweight vacuum cleaners require compactness, light weight, high output, high efficiency, and high strength.

[0004] Japanese Patent Application Laid-Open No. 2021-100377 discloses the shape of the protruding end of the teeth of a motor. Unlike a three-phase motor in which the direction of rotation of the rotor is determined, the disclosed motor is a single-phase motor in which the direction of rotation of the rotor is not determined because the number of magnetic poles of the rotor and the number of teeth of the stator are the same. In a single-phase motor, it is common to determine the direction of rotation of the rotor by making the circumferential shape of the flange portion protruding on both left and right sides of the protruding end of the tooth asymmetrical so as to make the sizes of the air gaps on both sides of the teeth different. In Japanese Patent Application Laid-Open No. 2021-100377, the diametric size of the flange portion is different in the direction of rotation in order to suppress saturation of the magnetic flux density and reduce iron loss. That is, the diametric size of the flange portion on the direction of rotation is larger than that on the counter-rotation side.

[0005] A vacuum cleaner according to one aspect of the present disclosure may include a suction fan and a dust collector. The suction fan may include a fan motor and an impeller that generates suction force necessary to suck up foreign substances on a surface to be cleaned while being rotated by the fan motor. The dust collector receives foreign substances sucked up from the surface to be cleaned. The fan motor may include a shaft rotatable around a rotational axis, a rotor fixed to the shaft, and a stator. The rotor includes a plurality of magnetic poles arranged in a rotational direction.

[0006] The stator may include an annular core ring, a plurality of teeth projecting from the core ring toward the rotational axis and arranged radially, and a plurality of coils arranged on each of the plurality of teeth.

[0007] Each of the plurality of teeth may include a protrusion facing the rotor with an air gap, a first flange portion protruding from the protrusion portion in the rotational direction, and a second flange portion protruding in a direction opposite to the rotational direction. The first flange portion and the second flange portion may be asymmetrical with respect to a center line of the teeth extending from the rotational axis.

[0008] A fan motor according to one aspect of the present disclosure may include a shaft rotatable about a rotational axis, a rotor fixed to the shaft, and a stator. The rotor includes a plurality of magnetic poles arranged in a rotational direction. The stator may include an annular core ring, a plurality of teeth protruding from the core ring toward the rotational axis and arranged radially, and a plurality of coils arranged on each of the plurality of teeth.

[0009] Each of the plurality of teeth may include a protrusion facing the rotor with an air gap, a first flange portion protruding from the protrusion portion in the rotational direction, and a second flange portion protruding in a direction opposite to the rotational direction. The first flange portion and the second flange portion may be asymmetrical with respect to a center line of the teeth extending from the rotational axis.

[0010] FIG. 1 is a schematic diagram of a vacuum cleaner according to one embodiment of the present disclosure.

[0011] FIG. 2 is a schematic cross-sectional view of a suction fan according to one embodiment of the present disclosure.

[0012] FIG. 3 is a schematic cross-sectional view of a fan motor according to one embodiment of the present disclosure.

[0013] FIG. 4 is an enlarged view of a protruding portion of a tooth according to one embodiment of the present disclosure.

[0014] Figure 5 is a schematic cross-sectional view of fan motor models according to embodiments and comparative examples applied to simulation.

[0015] Figure 6a shows the simulation results for the relationship between the protrusion amount of the first flange portion and the second flange portion and the total iron loss.

[0016] Figure 6b shows the simulation results for the relationship between the protrusion amount of the first flange portion and the second flange portion and the eddy current loss.

[0017] Figure 6c shows the simulation results for the relationship between the protrusion amount of the first flange portion and the second flange portion and the laminate thickness.

[0018] FIG. 7 is a schematic cross-sectional view of a fan motor according to one embodiment of the present disclosure.

[0019] It should be understood that the various embodiments and terms used in this document are not intended to limit the technical features described in this document to specific embodiments, but rather to include various modifications, equivalents, or substitutes of the embodiments.

[0020] In connection with the description of the drawings, similar reference numerals may be used for similar or related components.

[0021] The singular form of a noun corresponding to an item may include one or more of said items, unless the relevant context clearly indicates otherwise.

[0022] In this document, each of the phrases "A or B", "at least one of A and B", "at least one of A or B", "A, B, or C", "at least one of A, B, and C", and "at least one of A, B, or C" may include any one of the items listed together in that phrase, or all possible combinations thereof.

[0023] The term "and / or" includes any combination of a plurality of related described elements or any one of a plurality of related described elements.

[0024] Terms such as "first," "second," or "first" or "second" may be used simply to distinguish one component from another and do not qualify the components in any other respect (e.g., importance or order).

[0025] When a component (e.g., a first component) is referred to as being "coupled" or "connected" to another component (e.g., a second component), with or without the terms "functionally" or "communicatively," it means that the component can be connected to the other component directly (e.g., wired), wirelessly, or through a third component.

[0026] The terms "include" or "have" are intended to specify the presence of a feature, number, step, operation, component, part or combination thereof described in this document, but do not preclude the presence or addition of one or more other features, numbers, steps, operations, components, parts or combinations thereof.

[0027] When a component is said to be “connected,” “coupled,” “supported,” or “in contact with” another component, this includes not only cases where the components are directly connected, coupled, supported, or in contact, but also cases where the components are indirectly connected, coupled, supported, or in contact through a third component.

[0028] When we say that a component is "on" another component, this includes not only cases where the component is in contact with the other component, but also cases where there is another component between the two components.

[0029] To achieve high-efficiency, high-strength suction fans, rare-earth sintered magnets with strong magnetic force and high strength, such as neodymium magnets, can be used in the motor rotor. However, these magnets have low electrical resistivity, which can generate heat due to eddy currents in the magnets. If the rotor rotates at high speeds, the magnets can quickly become hot, making it difficult to apply rare-earth sintered magnets to the rotor. Considering this, suction fan motors typically use bonded magnets, which have low magnetic force but high electrical resistivity.

[0030] The present disclosure provides a suction fan having a structure capable of reducing heat generation in a rotor due to eddy currents, and a vacuum cleaner employing the same. The present disclosure also provides a suction fan having a structure capable of improving motor performance, and a vacuum cleaner employing the same. However, the technical problems to be solved in this document are not limited to the technical problems mentioned above, and other technical problems not mentioned will be clearly understood by those skilled in the art to which the present disclosure pertains from the description below.

[0031] Hereinafter, embodiments of a suction fan and a vacuum cleaner employing the same according to the present disclosure will be described in detail so that those skilled in the art can easily implement the present invention. However, the present invention may be implemented in various different forms and is not limited to the embodiments described herein. In addition, in the drawings, parts unrelated to the description have been omitted for clarity of description, and similar parts have been designated with similar reference numerals throughout the specification.

[0032] FIG. 1 is a schematic diagram of a vacuum cleaner according to one embodiment of the present disclosure. The vacuum cleaner illustrated in FIG. 1 is a stick-type vacuum cleaner, and will be simply referred to as a vacuum cleaner (1) hereinafter. The vacuum cleaner (1) may be a cordless type. However, the present disclosure is not limited thereto, and the present disclosure may also be applied to a handheld vacuum cleaner or a robot vacuum cleaner. Referring to FIG. 1, the vacuum cleaner (1) according to one embodiment of the present disclosure may be a cordless vacuum cleaner having a built-in rechargeable battery (6) and not requiring a power cord to be connected to an outlet during cleaning. The vacuum cleaner (1) according to one embodiment of the present disclosure may include a main body (3), a brush device (2a), and an extension tube (2). However, not all of the components illustrated in FIG. 1 are essential components. The vacuum cleaner (1) may be implemented with more components than those illustrated in FIG. 1, or may be implemented with fewer components. For example, the vacuum cleaner (1) may be implemented with a main body (3) and a brush device (2a) excluding an extension tube (2). In addition, the vacuum cleaner (1) may further include a station (not shown) for dust discharge of the main body (3) and charging of the battery (6).

[0033] The main body (3) may include a suction fan (10) that forms a vacuum inside the vacuum cleaner (1), a dust collector (dust bin) (4) that receives foreign substances sucked from a surface to be cleaned (e.g., a floor, bedding, a sofa, etc.), and a handle (5) that a user holds and moves the vacuum cleaner (1) during cleaning.

[0034] The main body (3) may include a mounting portion on which an extension pipe (2) or a brush device (2a) is mounted. The extension pipe (2) may be formed as a hollow pipe. The extension pipe (2) may have a predetermined rigidity. In addition, the extension pipe (2) may be formed as a flexible hose. A brush device (2a) may be detachably connected to one end of the extension pipe (2). The other end of the extension pipe (2) may be detachably connected to an extension pipe mounting portion of the main body (3). Through the extension pipe (2), a suction force generated by a suction fan (10) of the main body (3) may be transmitted to the brush device (2a), and air and foreign substances sucked through the brush device (2a) may be moved to the main body (3). The extension pipe (2) may be formed in multiple stages between the main body (3) and the brush device (2a). There may be two or more extension pipes (2).

[0035] The brush device (2a) is a device that adheres to the surface to be cleaned and sucks in air and foreign substances from the surface to be cleaned. The brush device (2a) may also be expressed as a vacuum cleaner head. The brush device (2a) may be rotatably coupled to the extension tube (2). The type of the brush device (2a) may vary. For example, the brush device (2a) may include, but is not limited to, a general brush (floor brush), a carpet brush, a bedding brush, a pet brush, a mop brush, a multipurpose brush (a brush that can be used on both carpets and floors), etc., depending on the intended use.

[0036] According to one embodiment of the present disclosure, each of the main body (3), the brush device (2a), and the extension tube (2) may include a power line (e.g., a + power line, a - power line) and a signal line. The power line may be a line for transmitting power supplied from the battery (6) to the main body (3) and, if necessary, to the brush device (2a) connected to the main body (3). The signal line is different from the power line and may be a line for transmitting and receiving signals between the main body (3) and the brush device (2a). The signal line may be implemented to be connected to the power line within the brush device (2a).

[0037] The main body (3) may include a suction force generating device (hereinafter referred to as a suction fan (10)) that generates suction force required to suck up foreign substances on a surface to be cleaned, a dust collector (4, also referred to as a dust container) that receives foreign substances sucked up from the surface to be cleaned, an exhaust unit (30), a filter unit (31), and a battery (6) that can supply power to the suction fan (10). Although not shown in the drawing, the main body (3) may further include a communication interface, a user interface, a main processor, and a memory.

[0038] The suction fan (10) may include a fan motor that converts electrical power into mechanical rotational power, an impeller that is connected to the fan motor and rotates, and a printed circuit board connected to the fan motor. The impeller is rotated by the fan motor to create a vacuum inside the cleaner (1). Here, vacuum means a state lower than atmospheric pressure. The fan motor may include a brushless motor, but is not limited thereto. The printed circuit board may include various electrical and electronic components for controlling the fan motor. The suction fan (10) may have an inverted motor structure in which the positions of the impeller and the printed circuit board are inverted. In the inverted motor structure, the printed circuit board may be located upstream of the fan motor and the impeller may be located downstream of the fan motor based on the airflow direction. Therefore, the impeller may be closer to the filter unit (31) than the printed circuit board. The suction fan (10) may be located across the dust collector (dust collector, 4) and the exhaust unit (30). The suction fan (10) will be described in detail later.

[0039] The dust collector (4) may be configured to filter and collect dust or dirt in the air flowing in through the brush device (2a). The dust collector (4) may be provided to be detachable from the main body (3). The dust collector (4) may collect foreign substances through a cyclone method that separates foreign substances using centrifugal force. Air from which foreign substances have been removed through the cyclone method may be discharged to the outside of the main body (3), and the foreign substances may be stored in the dust collector (4). A multi-cyclone may be arranged inside the dust collector (4). The dust collector (4) may be provided so that foreign substances are collected at the bottom of the multi-cyclone. The dust collector (4) may include a dust collector door (also referred to as a cover of the dust collector (4)) that is provided to open the dust collector (4) when connected to a station not shown. The dust collector (4) may include a first dust collector where relatively large foreign substances are primarily collected and a second dust collector where relatively small foreign substances are collected by a multi-cyclone. Both the first dust collector and the second dust collector may be arranged to be open to the outside when the dust collector door is opened.

[0040] Air passing through the dust collector (4) flows into the exhaust unit (30). The exhaust unit (30) may be, for example, a hollow cylinder, and may be provided with inner exhaust holes (30a) through which air is discharged on the outer periphery. For example, a filter unit (31) may be arranged to surround the periphery of the exhaust unit (30). The filter unit (31) may include a filter (32). The filter (32) may be, for example, cylindrical. The filter (32) may be arranged to surround the outer periphery of the exhaust unit (30). A plurality of outer exhaust holes (33) may be formed in the case of the main body (3) forming the outer periphery boundary of the filter unit (31). The filter unit (31) may include a filter (32) that filters ultrafine dust, etc., that are not filtered out by the dust collector (4). The filter (32) may include, but is not limited to, a motor filter, a HEPA filter, etc. Air flows into the filter section (31) from the exhaust section (30) through the inner exhaust hole (30a), passes through the filter (32), and is discharged to the outside of the cleaner (1) through the outer exhaust hole (33).

[0041] The battery (6) can be detachably mounted on the main body (3). The battery (6) may be expressed as a battery pack or a battery module. The battery (6) can be electrically connected to a charging terminal provided in the station. The battery (6) can be charged by receiving power from the charging terminal. According to one embodiment, the battery (6) may include a processor (e.g., MICOM (Micro-Computer, Microprocessor Computer, Microprocessor controller)) for controlling the voltage supplied to the main body (3) and communicating with the main processor. The battery (6) can perform data communication with the main processor. The battery (6) can periodically transmit information on the battery charge status, output voltage, etc. to the main processor.

[0042] The battery (6) may include an LED display to indicate the charging, discharging, or status of the battery. For example, the processor of the battery (6) may output red, orange, or yellow through the LED display depending on the charging rate, and when charging is complete, the LED display may output green.

[0043] The communication interface may include a module for performing communication with an external device. For example, the main body (3) may perform communication with a station or server device through the communication interface. The communication interface may include a short-range communication unit and a long-range communication unit, etc. The short-range communication unit (short-range wireless communication interface) may include a Bluetooth communication unit, a BLE (Bluetooth Low Energy) communication unit, a near field communication interface (NFC), a WLAN (Wi-Fi) communication unit, a Zigbee communication unit, an IrDA (Infrared Data Association) communication unit, a WFD (Wi-Fi Direct) communication unit, an UWB (ultra wideband) communication unit, an ANT+ communication unit, etc., but is not limited thereto. The long-range communication unit may be used for the main body (3) to remotely communicate with a server device. The long-range communication unit may include the Internet, a computer network (e.g., LAN or WAN), and a mobile communication unit. The mobile communications unit may include, but is not limited to, 3G modules, 4G modules, 5G modules, LTE modules, NB-IoT modules, LTE-M modules, etc.

[0044] A user interface may be provided on the handle (5) or the main body (3). The user interface may include an input interface and an output interface. The main body (3) can receive user input related to the operation of the cleaner (1) through the user interface, and can output information related to the operation of the cleaner (1). The main body (3) can output information on the operation status (e.g., operation mode), information on the remaining battery level, information on the docking status, information on the status of the dust bin (4), information on the status of the dust bag, information on moisture inflow, information on foreign matter caught in the brush device (2a), etc. through the user interface.

[0045] The input interface may include, but is not limited to, at least one of a motion input unit, a voice input unit (e.g., a microphone), or a manipulation input unit (e.g., a power button, a suction strength adjustment button). The output interface may include, but is not limited to, a light-emitting diode (LED) display, a liquid crystal display (LCD), a touch screen, a speaker, or the like.

[0046] The main body (3) may include at least one processor. The main body (3) may include one processor or may include multiple processors. For example, the main body (3) may include a main processor connected to a user interface and a processor connected to a fan motor. At least one processor may control the overall operation of the vacuum cleaner. For example, at least one processor may control the power consumption (suction force strength, suction force mode) of the fan motor, the drum RPM of the brush device (2a), the trip level of the brush device (2a), etc.

[0047] At least one processor according to the present disclosure may include at least one of a CPU (Central Processing Unit), a GPU (Graphics Processing Unit), an APU (Accelerated Processing Unit), a MIC (Many Integrated Core), a DSP (Digital Signal Processor), and an NPU (Neural Processing Unit). The at least one processor may be implemented in the form of an integrated system on a chip (SoC) including one or more electronic components. Each of the at least one processors may be implemented as separate hardware (H / W). The at least one processor may be expressed as a MICOM (Micro-Computer, Microprocessor Computer, Microprocessor controller), an MPU (Micro Processor unit), or an MCU (Micro Controller Unit).

[0048] At least one processor according to the present disclosure may be implemented as a single core processor or as a multicore processor.

[0049] The memory may store programs for processing and controlling at least one processor, and may also store input / output data. For example, the memory may store a pre-learned artificial intelligence (AI) model (e.g., SVM (Support Vector Machine) algorithm, etc.), status data of the fan motor, measurement values ​​of a pressure sensor measuring the pressure of the oil path, status data of the battery (6), status data of the brush device (2a) (e.g., RPM of the drum), error occurrence data (failure history data), power consumption of the fan motor corresponding to the operating condition, operation sequence of the fan motor corresponding to the suction force generation pattern, type of brush device (2a) corresponding to the voltage value input through the signal line, constraint level by type of brush device (2a), PWM frequency by type of brush device (2a), average input voltage by type of brush device (2a), high load reference value (or low load reference value) by type of brush device (2a), information on movement patterns (user gestures) defined in response to multiple control commands, information on moisture inflow into the main body (3), reference load values ​​for distinguishing the state of the surface to be cleaned (e.g., floor or carpet) (e.g., multiple reference loads corresponding to multiple suction power modes) You can store values, etc.

[0050] The memory may include external memory and internal memory. For example, the memory may include at least one type of storage medium among a flash memory type, a hard disk type, a multimedia card micro type, a card type memory (e.g., SD or XD memory), a RAM (Random Access Memory), a SRAM (Static Random Access Memory), a ROM (Read-Only Memory), an EEPROM (Electrically Erasable Programmable Read-Only Memory), a PROM (Programmable Read-Only Memory), a magnetic memory, a magnetic disk, and an optical disk. Programs stored in the memory may be classified into a plurality of modules according to their functions.

[0051] FIG. 2 is a schematic cross-sectional view of a suction fan (10) according to one embodiment of the present disclosure. Referring to FIG. 2, the suction fan (mini fan) (10) may include a fan motor (13) and an impeller (20) rotated by the fan motor (13). The impeller (20) is disposed in the main body (3) and rotates to generate suction force necessary to suck up foreign substances on the surface to be cleaned. The suction fan (10) may further include a shroud (11) having a path (air passage (40)) formed therein through which air flows. For example, the impeller (20) generates suction force so that air is sucked from the dust collector (4) into the main body (3) through the air passage (40). The suction fan (10) may further include a diffuser (15). In FIG. 2, the diffuser (15) is illustrated in its external shape on the left side and in its cross-sectional shape on the right side with respect to the rotation axis (A). Foreign substances sucked from the cleaning surface are collected in the dust collector (4).

[0052] A shroud (11) covers the outside of the air passage (40). When the impeller (20) rotates, the air inside the air passage (40) flows as indicated by the arrow (Y1) in Fig. 2. Hereinafter, the terms “upstream” and “downstream” are based on the direction of air flow (Y1). The shroud (11) may be a cylindrical member having a concave center. The shroud (11) may include an upstream-side large-diameter portion (11a) having a large inner diameter, a small-diameter portion (11c) having a smallest inner diameter, and a downstream-side large-diameter portion (11b) having a large inner diameter. The small-diameter portion (11c) is positioned between the upstream-side large-diameter portion (11a) and the downstream-side large-diameter portion (11b). A relay area (11d) is provided in each of the downstream portion of the upstream-side large-diameter portion (11a) and the upstream portion of the downstream-side large-diameter portion (11b). Each relay area (11d) has a shape in which the inner diameter gradually decreases from each of the upstream-side large-diameter portion (11a) and the downstream-side large-diameter portion (11b) toward the small-diameter portion (11c).

[0053] Referring to Fig. 1, the suction fan (10) can be accommodated inside the main body (3) so that a portion thereof is partially inserted into the exhaust section (30). The downstream side large diameter section (11b) is arranged inside the exhaust section (30). The upstream side large diameter section (11a) is arranged so as to be partially inserted into the inside of the dust collector (4) while being covered around the filter case (4a) capable of removing dust in the air.

[0054] From a functional perspective of the windway (40), the shroud (11) may include a moving blade portion (11P), a suction portion (11V) extending upstream from the moving blade portion (11P), and a static blade portion (11E) extending downstream from the moving blade portion (11P). The moving blade portion (11P) may include a portion extending from a small diameter portion (11c) to a relay area (11d) of a large diameter portion (11b) on the downstream side. Therefore, the moving blade portion (11P) has a shape in which the inner diameter gradually increases from the upstream side to the downstream side. An impeller (20) is accommodated in the moving blade portion (11P).

[0055] The suction part (11V) may include an upstream large-diameter part (11a) and a relay region (11d) connecting the upstream large-diameter part (11a) and the small-diameter part (11c). Therefore, the inner diameter of the suction part (11V) gradually decreases from the upstream side to the downstream side of the air passage (40), and air flows from the outer side in the radial direction toward the inner side of the suction part (11V) along the inner surface of the suction part (11V). A fan motor (13) is accommodated in the suction part (11V). The stator part (11E) may include a downstream large-diameter part (11b). A diffuser (15) is accommodated in the stator part (11E).

[0056] The fan motor (13) may include a shaft (13a), a rotor (13b), and a stator (13c). A motor case (12) is accommodated in the upstream large-diameter portion (11a). In the center of the motor case (12), a shaft (13a) is supported rotatably about a rotation axis (A) via a bearing (12a). A rotor (13b) is fixed to the middle portion of the shaft (13a). The stator (13c) is assembled to the motor case (12) so that the stator (13c) is positioned around the rotor (13b) with an air gap (Ga) therebetween. Accordingly, a fan motor (13) including a shaft (13a), a rotor (13b), and a stator (13c) can be placed in the center portion of the suction portion (11V). The fan motor (13) can be integrated with the motor case (12). The rotation axis (A) of the fan motor (13) is aligned with the center of the motor case (12) and the shroud (11). The fan motor (13) will be described in detail later.

[0057] One end of the shaft (13a) protrudes from the motor case (12). The motor case (12) is inserted into and accommodated in the shroud (11) such that the protruding end of the shaft (13a) faces downstream. As a result, an air passage (40) is formed between the fan motor (13) and the inner surface of the suction portion (11V) of the shroud (11), i.e., the inner surface of the upstream large-diameter portion (11a).

[0058] A control unit (14) for controlling a fan motor (13) may be installed on the upstream side of the motor case (12). The control unit (14) may include a printed circuit board on which electronic components such as a motor drive IC are mounted. For example, the fan motor (13) is positioned on the upstream side of the impeller (20) within the air passage (40), and the control unit (14) is disposed on the upstream side with respect to the fan motor (13) within the air passage (40). The control unit (14) may be disposed such that its printed circuit board crosses the air passage (40). The control unit (14) controls the operation of the fan motor (13) according to an operation signal input through a user interface of the cleaner (1).

[0059] The fan motor (13) is compact. The outer diameter of the stator (13c) is 50 mm or less, and the overall height is 80 mm or less, so that it can be the size of a palm. For example, in the present embodiment, the outer diameter of the stator (13c) is approximately 40 mm, and the height is approximately 70 mm. Therefore, the weight of the fan motor (13) is also very lightweight. Such a fan motor (13) can be referred to as a mini fan motor.

[0060] The fan motor (13) is configured to obtain high output with high efficiency so as to obtain sufficient performance that can be used in the vacuum cleaner (1) by utilizing the power of the battery (6). For example, a power of 500 W or more can be input to the fan motor (13) according to one embodiment of the present disclosure, and thus it is configured to be capable of outputting at an ultra-high speed rotation of 100,000 rpm or more.

[0061] The diffuser (15) is accommodated in the fin section (11E). In this embodiment, the diffuser (15) may include an upper diffuser (15U) and a lower diffuser (15D). Depending on the specifications of the suction fan (10), there may be one diffuser (15) or three or more.

[0062] Each of the upper diffuser (15U) and the lower diffuser (15D) may be a cylindrical member, and a plurality of vanes (15a) extending obliquely with respect to the axial direction (e.g., the direction of the rotation axis (A)) are formed on the outer surface of each. The inclination angle of the vanes (15a) of the lower diffuser (15D) is smaller than that of the upper diffuser (15U). Each of the upper diffuser (15U) and the lower diffuser (15D) is fixed to the inner surface of the downstream large-diameter portion (11b).

[0063] As described above, the impeller (20) is arranged on the blade portion (11P) of the shroud (11) forming the air passage (40). The impeller (20) may include a boss portion (21) that is fixed with the rotation axis (A) aligned with the shaft (13a) of the fan motor (13), an annular base portion (22) that extends from the boss portion (21) to the periphery, and a plurality of blades (23). The plurality of blades (23) are arranged radially on the base portion (22) to generate a suction force in the air passage (40).

[0064] During operation of the vacuum cleaner (1), the shaft (13a) of the fan motor (13) rotates at high speed in a certain direction, in this embodiment, counterclockwise when viewed from the upstream side (see Fig. 3). As a result, the impeller (20) rotates at a very high speed, so that, as indicated by the arrow (Y1) in Fig. 2, air flows from the dust collector (4) through the motor case (12) into the shroud (11), generating suction force on the upstream side of the rotor section (11P), i.e., the suction section (11V).

[0065] The air flowing toward the shroud (11) is sucked into the rotor blade (11P) while cooling the control unit (14) and the fan motor (13) in an air-cooled manner. Since the control unit (14) and the fan motor (13) generate more heat as the speed increases or the suction power increases, it is important to cool them. In the suction fan (10) according to one embodiment of the present disclosure, since the control unit (14) and the fan motor (13) are arranged on the upstream side of the rotor blade (11P), the control unit (14) and the fan motor (13) can exchange heat with air having a relatively low temperature, which is the same as the outside air. Therefore, the cooling performance of the control unit (14) and the fan motor (13) is excellent.

[0066] The air is concentrated while being bent from the outer periphery toward the center within the intake (11V) and flows toward the rotor blade (11P). Specifically, the air flows axially along the inner surface of the upstream large-diameter portion (11a) and the outer surface of the fan motor (13), and then flows from the outer periphery (outer in the diametric direction) toward the center (inner in the diametric direction) along the inner surface of the relay area (11d) of the upstream large-diameter portion (11a) and the end of the fan motor (13) toward the rotor blade (11P). As a result, the air efficiently contacts and flows toward the control unit (14) and the fan motor (13), so that heat exchange between the control unit (14) and the fan motor (13) is facilitated. Therefore, the cooling performance of the control unit (14) and the fan motor (13) is further improved.

[0067] Air introduced into the rotor blade (11P) passes through the space between the inner surface of the rotor blade (11P) and the base portion (22) of the impeller (20) (specifically, between the plurality of blades (23)) and is introduced into the stator blade (11E). Air introduced into the stator blade (11E) passes through the space between the inner surface of the stator blade (1E) and the outer surface of the diffuser (15) (specifically, between the plurality of vanes (15a)) and is introduced into the exhaust portion (30).

[0068] By passing through the diffuser (15), air is introduced into the exhaust section (30) in a axially rectified state. The air introduced into the exhaust section (30) flows out to the filter section (31) through the inner exhaust hole (30a) and is exhausted out of the main body (3) through the outer exhaust hole (33).

[0069] FIG. 3 is a schematic cross-sectional view of a fan motor (13) according to one embodiment of the present disclosure. Referring to FIG. 3, the fan motor (13) may include a shaft (13a), a rotor (13b), and a stator (13c). The shaft (13a) may rotate around a rotational axis (A).

[0070] The rotor (13b) includes a plurality of magnetic poles arranged in the direction of rotation. The rotor (13b) may be formed, for example, by a cylindrical permanent magnet (50). The plurality of magnetic poles include N poles and S poles that are arranged alternately. In the present embodiment, the rotor (13b) includes four magnetic poles. The four magnetic poles may be arranged at equal intervals in the circumferential direction of the rotor (13b). Two N poles and two S poles are arranged at equal intervals in the circumferential direction of the rotor (13b). The structure of the rotor (13b) is not limited thereto. Although not illustrated in the drawing, the rotor (13b) may also be formed by attaching permanent magnets (50) to the surface of a rotor core formed by axially laminating steel plates.

[0071] The stator (13c) may include a core ring (61), a plurality of teeth (62), and a plurality of coils (65). For example, the stator (13c) includes a stator core (60) formed by axially stacking steel plates. The stator core (60) according to the present embodiment is formed by alternately connecting two types of parts (a first part (60a) and a second part (60b)) each consisting of six parts in the circumferential direction. Accordingly, the stator core (60) includes an annular core ring (61) and a plurality of teeth (62) that protrude inwardly from the core ring (61), that is, toward the rotational axis (A), and are arranged radially. The stator core (60) according to the present embodiment includes six teeth (62). The six teeth (62) protrude radially inwardly from the annular core ring (61) and are arranged at equal intervals in the circumferential direction. The teeth (62) are spaced apart from the rotor (13b) with an air gap (Ga) between them. Except for the surface facing the air gap (Ga), the inner surface of the stator core (60) is covered with an insulator (not shown).

[0072] A coil (65) is connected to each of the plurality of teeth (62) by winding a wire around each of the plurality of teeth (62) through a slot (64) between two adjacent teeth (62). The plurality of coils (65) form a three-phase coil group consisting of a U phase, a V phase, and a W phase. Specifically, in the case of the fan motor (13) according to the present embodiment, since there are six teeth (62), two coils (65) facing each other are electrically connected to form a coil group forming one phase.

[0073] The pole / slot combination of the fan motor (13) according to the present embodiment is 4 poles / 6 slots. However, it is not limited thereto, and the pole / slot combination of the fan motor (13) may be 2 poles / 3 slots or 6 poles / 9 slots. In other words, since the fan motor (13) according to the present embodiment is very small, the pole / slot combination is preferably 2n poles / 3n slots (n=1, 2, 3).

[0074] The fan motor (13) is a so-called three-phase motor. Therefore, by supplying currents of different phases to the coil groups of each phase, for example, the U-phase coil group, the V-phase coil group, and the W-phase coil group, at a predetermined cycle, the rotor (13b) can be started to rotate in a certain direction. For example, as described above, when viewed from the upstream side to the downstream side based on the air flow direction, the rotor (13b) can rotate counterclockwise.

[0075] In a fan motor (13) according to one embodiment of the present disclosure, a rare earth sintered magnet having a strong magnetic force is employed as a permanent magnet (50) of a rotor (13b). Examples of rare earth sintered magnets that can be employed in the rotor (13b) include neodymium magnets, samakova magnets, Al-Ni-Co magnets, and the like. For example, a neodymium magnet may be employed as the permanent magnet (50). There are also bonded magnets or rubber magnets formed by mixing powder of these rare earth sintered magnets with synthetic resin or rubber, but rare earth sintered magnets are preferable for the magnetic pole of the rotor (13b) because they have high purity and a stronger magnetic force than bonded magnets.

[0076] Meanwhile, while bonded magnets and the like have difficulty conducting electricity, rare earth sintered magnets conduct electricity very easily. Specifically, the electrical resistivity of bonded magnets and the like is typically 10,000Ω·cm or higher, whereas the electrical resistivity of rare earth sintered magnets is 10Ω·cm or less. Therefore, when rare earth sintered magnets are used for stimulation, eddy currents are likely to be generated and heat generation is likely to occur. Accordingly, when a rotor (13b) employing a rare earth sintered magnet rotates at ultra-high speed, it immediately becomes hot, making temperature control very difficult. For this reason, it is common to use bonded magnets with weak magnetic force in the rotor (13b).

[0077] However, in order to realize further high efficiency and high strength of the fan motor (13), it is unavoidable to form the magnetic pole of the rotor (13b) with a strong permanent magnet (50). Therefore, the teeth (62) of the fan motor (13) according to the present embodiment have a protruding end shape that can effectively suppress the generation of eddy current and reduce heat generation even when a permanent magnet (50) with very small electrical resistivity through which electricity flows is adopted.

[0078] Referring to FIG. 3, each of the plurality of teeth (62) has a prism shape extending radially inward from the core ring (61). Each of the plurality of teeth (62) includes a protrusion (66) close to the rotor (13b). The protrusion (66) faces the rotor (13b) with an air gap (Ga). FIG. 4 is an enlarged view of the protrusion (66) of the teeth (62) according to one embodiment of the present disclosure. Referring to FIG. 4, when viewed in the axial direction, a center line (CL) of each tooth (62) intersects the rotational axis (A). The teeth (62) include a pair of side surfaces (70a) (70b) that are equidistant from the center line (CL) and are approximately parallel to each other. The pair of side surfaces (70a) (70b) face slots (64) that are located on both sides of the teeth (62).

[0079] A pair of flange portions (71) (72) protrude from a pair of side surfaces (70a) (70b) at the protrusion end (66) of the tooth (62), i.e., a portion close to the rotor (13b). In the case of a three-phase motor, the pair of flange portions (71) (72) are generally symmetrical from the viewpoint of ripple suppression, etc. However, since the fan motor (13) according to one embodiment of the present disclosure is a motor that rotates in a certain direction, by employing a pair of flange portions (71) (72) of an asymmetrical shape, leakage flux is reduced, performance is improved, and the generation of eddy current is effectively suppressed.

[0080] Specifically, a flange portion (first flange portion (71)) protruding in the rotational direction (counterclockwise in the fan motor (13) of the present embodiment) and a flange portion (second flange portion (72)) protruding in the opposite direction of the rotational direction (clockwise in the fan motor (13) of the present embodiment) are provided on each protrusion (66) of the teeth (62).

[0081] The protrusion amount from a pair of side surfaces (70a) (70b) of the first and second flange portions (71) (72) increases toward the rotation axis (A). In other words, the first and second flange portions (71) (72) are formed so as to protrude more in the circumferential direction from a pair of side surfaces (70a) (70b) of the tooth (62) radially inward. Therefore, at the boundary portions of the first and second flange portions (71) (72) and the two side surfaces (70a) (70b) of the tooth (62), there exist inflection points where the surface shape significantly changes, i.e., a first inflection point (73a) and a second inflection point (73b). The distance (D1) from the rotation axis (A) to the first inflection point (73a) of the first flange portion (71) and the distance (D2) from the rotation axis (A) to the second inflection point (73b) of the second flange portion (72) are the same. That is, the radial lengths of both sides (70a) (70b) of the tooth (62) are the same. Therefore, even if the shapes of the first flange portion (71) and the second flange portion (72) are asymmetrical, adverse effects caused by the flange portion, such as a decrease in the space factor of the coil (65) wound around the tooth (62) and collapse of the winding, can be prevented.

[0082] The first flange portion (71) includes a facing surface (75) facing the air gap (Ga). The facing surface (75) is a surface of a protruding end (66) of a tooth (62) extending in the rotational direction from the center line (CL). This facing surface (75) is referred to as a first facing surface (75). The first facing surface (75) has an arc shape concentric with the outer surface of the rotor (13b). Therefore, the distance (first gap (G1)) between the first facing surface (75) of the first flange portion (71) and the outer surface of the rotor (13b) is approximately constant over the entire first facing surface (75).

[0083] The second flange portion (72) includes a facing surface (76) facing the air gap (Ga). The facing surface (76) is a surface of a protruding end (66) of a tooth (62) extending from the center line (CL) in the counter-rotation direction. This facing surface (76) is referred to as a second facing surface (76). The second facing surface (76) is a plane perpendicular to the center line (CL) of the tooth (62). Therefore, the distance (second gap (G2)) between the second facing surface (76) of the second flange portion (72) and the outer circumferential surface of the rotor (13b) increases in the counter-rotation direction.

[0084] By doing so, the distance (TD) between the first flange portion (71) of one tooth (62) and the second flange portion (72) of another adjacent tooth (62) becomes larger than in the case of a tooth having a pair of symmetrical flange portions. As a result, the performance of the fan motor (13) can be improved because the leakage flux is reduced.

[0085] And since the second gap (G2) gradually increases as it moves away from the center line (CL) of the teeth (62), the magnetic flux on the counter-rotation side of each tooth (62) gradually weakens. As a result, the eddy current generated in the permanent magnet (50) of the rotor (13b) is reduced, so that the heat generation of the permanent magnet (50) can be effectively suppressed. As a result, a rare earth sintered magnet with a small electrical resistivity can be employed in the rotor (13b), thereby strengthening the magnetic force of the magnetic pole of the rotor (13b).

[0086] Meanwhile, as the second gap (G2) increases, the torque of the fan motor (13) may decrease. In contrast, since the first gap (G1) is approximately constant, the decrease in torque can be suppressed on the rotation side of each tooth (62). Therefore, since the eddy current can be reduced while suppressing the decrease in torque, the performance of the fan motor (13) can be improved in a balanced manner.

[0087] In addition, the distance (protrusion amount of the second flange (72)) (W2) from the center line (CL) of the tooth (62) to the protrusion end (71a) of the first facing surface (75) (protrusion amount of the first flange (71)) can be made larger than the distance (protrusion amount of the second flange (72)) (W1) from the center line (CL) of the tooth (62) to the protrusion end (72b) of the second facing surface (76).

[0088] The inventors of the present invention examined the influence of the protrusion amount of the first flange portion (71) and the second flange portion (72) on the main characteristics through simulation. Specifically, by using a motor model, the protrusion amount (W1) of the first flange (71) and the protrusion amount (W2) of the second flange (72) were changed between 1.8 mm and 2.6 mm, and the influence on the loss (total iron loss) due to the core of the rotor (13b) and the stator (13c), the loss due to the eddy current of the rotor (13b), and the laminated thickness of the stator core (60) were investigated.

[0089] From the perspective of improving efficiency, it is desirable that the total iron loss and eddy current loss be small. From the perspective of weight reduction, it is desirable that the laminate thickness be small. As the laminate thickness increases, the coil (65) also becomes larger, and the thickness of the rotor (13b) also increases, which has a significant impact on the weight.

[0090] Referring to Fig. 5, as an example, a simplified motor model of the fan motor (13) described above was used. That is, the slot combination, shape of the teeth, etc. of the motor model are the same as those of the fan motor (13) described above. As a comparative example, a motor model in which the two flange parts of the teeth are symmetrical (the shape of the first flange part (71) is applied to both flange parts) was used, as in the prior art. L represents the protrusion amount (W1), and R on the horizontal axis represents the protrusion amount (W2).

[0091] Figures 6a, 6b, and 6c are graphs showing simulation results. Figure 6a shows the simulation result for the relationship between the protrusion amount of the first flange part and the second flange part and the total iron loss. Figure 6b shows the simulation result for the relationship between the protrusion amount of the first flange part and the second flange part and the eddy current loss. Figure 6c shows the simulation result for the relationship between the protrusion amount of the first flange part and the second flange part and the laminate thickness. The graphs of Figures 6a, 6b, and 6c show the simulation results when the air gap (Ga) is 0.5 mm. In the graphs of Figures 6a, 6b, and 6c, L on the vertical axis represents the protrusion amount (W1), and R on the horizontal axis represents the protrusion amount (W2). In the graphs of Figures 6a, 6b, and 6c, the arrows indicate the direction in which the total iron loss, eddy current loss, and laminate thickness increase, and the dashed lines indicate isolines of the total iron loss, eddy current loss, and laminate thickness. The total iron loss has a larger relative loss amount than the eddy current loss, and its influence is significant.

[0092] Referring to Fig. 6a, in the comparative example, as L increases and R decreases, the total iron loss decreases, and as L decreases and R increases, the total iron loss increases. In contrast, in the embodiment, as L increases, the total iron loss decreases, and as L decreases, the total iron loss increases, but the size of R does not significantly affect the total iron loss. Therefore, in the embodiment, the size of R can be selected while minimizing the total iron loss. In contrast, in the comparative example, minimizing the total iron loss is limited to specific conditions (L = 2.6 mm, R = 1.8 mm). In addition, the smallest value of the total iron loss in the comparative example is 16.7 W, whereas in the embodiment it is 15.1 W, indicating that the embodiment can reduce the total iron loss by about 10%.

[0093] Referring to FIGS. 6b and 6c, it can be seen that there is no significant difference in the influence of the sizes of L and R on the eddy current loss and the laminate thickness between the examples and the comparative examples. However, since the size of R can be selected in the examples, the optimal value of R can be selected by considering the influence of both the eddy current loss and the laminate thickness.

[0094] Specifically, as described above, the distance (W1) from the center line (CL) of the teeth (62) to the protruding end (71a) of the first facing surface (75) may be made longer than the distance (W2) from the center line (CL) of the teeth (62) to the protruding end (72b) of the second facing surface (76). In the case of the fan motor (13) according to the exemplary embodiment, for example, L=2.6 mm and R=2.2 mm may be selected as the optimal conditions.

[0095] In contrast, in the comparative example, even under the condition of the smallest total iron loss (L=2.6, R=1.8), the eddy current loss is 3.25 W, which is larger than 2.1 W under the optimal condition of the embodiment. Similarly, in the comparative example, under the condition of the smallest total iron loss (L=2.6, R=1.8), the lamination thickness is 15.3 mm, whereas under the optimal condition of the embodiment, the lamination thickness is 15.6 mm, showing almost no difference.

[0096] Therefore, by employing an embodiment, that is, a pair of asymmetrical flange parts, the total iron loss and eddy current loss can be reduced without causing an increase in weight compared to a comparative example, that is, a case where conventional symmetrical flange parts are employed.

[0097] The embodiment of the suction fan (10) is not limited to the above-described embodiment. Fig. 7 is a schematic cross-sectional view of a fan motor (13) according to one embodiment of the present disclosure.

[0098] For example, in the above-described embodiment, a fan motor (13) is illustrated in which a permanent magnet (50) is arranged on the outer surface of a rotor (13b). When the rotor (13b) rotates at high speed, there is a risk that the permanent magnet (50) may fall off and fly away. In order to prevent the permanent magnet (50) from flying away, the outer surface of the rotor (13b) may be covered with a cylindrical metal cover (80), as illustrated in Fig. 7.

[0099] In the case of the fan motor (13) according to the embodiment illustrated in Fig. 7, heat generation due to eddy current may occur in the metal cover (80). Such eddy current loss occurs equally even when a permanent magnet (50) with high electrical resistivity, such as a ferrite magnet or a bonded magnet, is employed for the magnetic pole of the rotor (13b). Therefore, the structure of wrapping the outer circumference of the rotor (13b) with a metal cover (80) can still be applied to the fan motor (13) according to the present disclosure.

[0100] A vacuum cleaner according to one aspect of the present disclosure may include a suction fan including a fan motor and an impeller that generates a suction force necessary to suck up foreign substances on a surface to be cleaned while being rotated by the fan motor; and a dust collector that receives foreign substances sucked up from the surface to be cleaned. The fan motor may include a shaft rotatable around a rotational axis; a rotor fixed to the shaft, the rotor including a plurality of magnetic poles arranged in a rotational direction; and a stator including an annular core ring, a plurality of protruding teeth that protrude from the core ring toward the rotational axis and are radially arranged, and a plurality of coils arranged on each of the plurality of teeth. Each of the plurality of teeth may include a protruding end opposing the rotor with an air gap therebetween, a first flange portion protruding from the protruding end in the rotational direction, and a second flange portion protruding in a direction opposite to the rotational direction. The first flange portion and the second flange portion may be asymmetrical with respect to a center line of the teeth extending from the rotational axis.

[0101] According to this configuration, the distance between the first flange portion of a tooth and the second flange portion of an adjacent tooth is increased compared to a structure in which the first flange portion and the second flange portion are symmetrical with respect to the center line. Therefore, the leakage flux is reduced, thereby improving the performance of the fan motor.

[0102] As one embodiment, the second flange portion may include a second facing surface facing the air gap and extending from the center line in a direction opposite to the rotational direction. A second gap, which is a distance between the second facing surface and the outer peripheral surface of the rotor, may increase in a direction opposite to the rotational direction.

[0103] As the second gap gradually increases as it moves away from the centerline of the teeth, the magnetic flux on the counter-rotation side of the teeth gradually weakens. This reduces the generation of eddy currents in the rotor, effectively suppressing rotor heat generation. As a result, rare-earth sintered magnets with low electrical resistivity can be employed in the rotor, thereby strengthening the magnetic force of the rotor's magnetic poles.

[0104] As an example, the first flange portion may include a first facing surface facing the air gap and extending in the rotational direction from the center line. A first gap, which is a distance between the first facing surface and the outer peripheral surface of the rotor, may be constant.

[0105] As the second gap increases, the motor torque may decrease. However, by maintaining the first gap constant, the torque decrease on the rotation side of the teeth can be suppressed. Therefore, by suppressing the torque decrease while reducing eddy current, the fan motor performance can be improved in a balanced manner.

[0106] As an example, the first facing surface may have an arc shape concentric with the outer surface of the rotor, and the second facing surface may be a plane perpendicular to the center line.

[0107] As an example, the distance from the center line to the protruding end of the second facing surface may be greater than the distance from the center line to the protruding end of the first facing surface.

[0108] According to this configuration, as described with reference to FIGS. 6A, 6B, and 6C, the iron loss and eddy current loss can be reduced in a balanced manner while maintaining the lamination thickness of the stator core, thereby achieving both weight reduction and improved efficiency of the fan motor.

[0109] In one embodiment, each of the plurality of teeth may include a pair of side surfaces positioned equidistant from the center line. The first flange portion and the second flange portion may each protrude from the pair of side surfaces. The amount of protrusion from the pair of side surfaces of the first flange portion and the second flange portion may increase toward the rotational axis.

[0110] As an example, the distance from the rotation axis to the first inflection point, which is the boundary between the first flange portion and the side surface, and the distance from the rotation axis to the second inflection point, which is the boundary between the second flange portion and the side surface, may be the same.

[0111] With this configuration, the lengths of the pair of side surfaces from which the first flange portion and the second flange portion protrude are identical. Therefore, even if the shapes of the first flange portion and the second flange portion are asymmetrical, adverse effects caused by the flange portion, such as a decrease in the space factor of the coil wound on the tooth and collapse of the winding, can be prevented.

[0112] As an example, the plurality of coils may form a three-phase coil group.

[0113] As an example, the rotor may include a permanent magnet having the plurality of magnetic poles and an electrical resistivity of 10Ω·cm or less.

[0114] Although rare-earth sintered magnets with strong magnetic force are preferred for the magnetic poles of the rotor, rare-earth sintered magnets have an electrical resistivity of 10 Ω·cm or less, making them very easy for electricity to flow. Therefore, if the magnetic poles are formed with such permanent magnets, eddy currents are likely to be generated. However, according to the fan motor according to the present disclosure, the generation of eddy currents can be suppressed by the asymmetrical configuration of the first flange portion and the second flange portion, and thus rare-earth sintered magnets can be employed for the magnetic poles of the rotor. Therefore, the performance of the fan motor can be improved.

[0115] As one embodiment, the fan motor may include a metal cover surrounding an outer surface of the rotor.

[0116] There is a risk that the permanent magnets may fall and scatter when the rotor rotates at high speed, but by using a metal cover, scattering of the permanent magnets can be prevented.

[0117] A fan motor according to one aspect of the present disclosure may include: a shaft rotatable about a rotational axis; a rotor fixed to the shaft, the rotor including a plurality of magnetic poles arranged in a rotational direction; and a stator including an annular core ring, a plurality of protruding teeth protruding from the core ring toward the rotational axis and radially arranged, and a plurality of coils arranged on each of the plurality of teeth. Each of the plurality of teeth may include a protruding end opposing the rotor with an air gap, a first flange portion protruding from the protruding end in the rotational direction, and a second flange portion protruding in a direction opposite to the rotational direction. The first flange portion and the second flange portion may be asymmetrical with respect to a center line of the teeth extending from the rotational axis.

[0118] In one embodiment, the first flange portion may include a first facing surface facing the air gap and extending from the center line in the rotational direction. The second flange portion may include a second facing surface facing the air gap and extending from the center line in a direction opposite to the rotational direction. A first gap, which is a distance between the first facing surface and the outer peripheral surface of the rotor, may be constant. A second gap, which is a distance between the second facing surface and the outer peripheral surface of the rotor, may increase in a direction opposite to the rotational direction.

[0119] As an example, the distance from the center line to the protruding end of the second facing surface may be greater than the distance from the center line to the protruding end of the first facing surface.

[0120] As an example, the rotor may include a permanent magnet having the plurality of magnetic poles and an electrical resistivity of 10Ω·cm or less.

[0121] As an example, the rotor may include a metal cover surrounding the outer surface of the rotor.

[0122] The technical effects to be achieved in this document are not limited to the technical effects mentioned above, and other technical effects not mentioned can be clearly understood by a person having ordinary skill in the technical field to which the present disclosure pertains from the description of this document.

[0123] As described above, although the vacuum cleaner and fan motor of the present disclosure have been described by limited embodiments and drawings, the present disclosure is not limited to the above embodiments, and various modifications are possible without departing from the spirit thereof.

Claims

1. A suction fan (10) including a fan motor (13) and an impeller (20) that rotates by the fan motor and generates suction force necessary to suck up foreign substances on a surface to be cleaned; Includes a dust collector (4) that receives foreign substances sucked from the cleaning surface; The above fan motor, A shaft (13a) rotatable around a rotation axis (A); A rotor (13b) fixed to the shaft, comprising a plurality of stimuli arranged in the direction of rotation; It comprises a stator (13c) including an annular core ring (61), a plurality of protruding teeth (62) that protrude from the core ring toward the rotation axis and are arranged radially, and a plurality of coils (65) arranged on each of the plurality of teeth; Each of the above plurality of teeth includes a protrusion (66) facing the rotor with an air gap (Ga), a first flange portion (71) protruding from the protrusion (66) in the rotational direction, and a second flange portion (72) protruding in the opposite direction to the rotational direction. A cleaner wherein the first flange portion and the second flange portion are asymmetrical with respect to the center line (CL) of the teeth extending from the rotation axis.

2. In paragraph 1, The above second flange portion includes a second opposing surface (76) facing the air gap and extending in the opposite direction of the rotational direction from the center line, A cleaner in which the second gap (G2), which is the distance between the second opposing surface and the outer surface of the rotor, increases in the direction opposite to the rotational direction.

3. In paragraph 2, The above first flange portion includes a first opposing surface (75) facing the air gap and extending in the rotational direction from the center line, A vacuum cleaner in which the first gap (G1), which is the distance between the first opposing surface and the outer surface of the rotor, is constant.

4. In paragraph 3, The above first opposing surface has an arc shape concentric with the outer surface of the rotor, A cleaner in which the second opposing surface is a plane perpendicular to the center line.

5. In paragraph 3 or 4, A cleaner in which the distance (W2) from the center line to the protruding end (72b) of the second facing surface is greater than the distance (W1) from the center line to the protruding end (71a) of the first facing surface.

6. In any one of paragraphs 1 to 5, Each of the above plurality of teeth includes a pair of side surfaces (70a)(70b) positioned equidistant from the center line, The first flange portion and the second flange portion each protrude from the pair of side surfaces, A cleaner wherein the amount of protrusion from the pair of side surfaces of the first flange portion and the second flange portion increases toward the rotation axis.

7. In paragraph 6, A cleaner in which the distance (D1) from the rotation axis to the first inflection point (73a), which is the boundary between the first flange portion and the side surface (70a), is the same as the distance (D2) from the rotation axis to the second inflection point (73b), which is the boundary between the second flange portion and the side surface (70b).

8. In any one of paragraphs 1 to 7, A cleaner in which the above plurality of coils form a three-phase coil group.

9. In any one of paragraphs 1 to 8, A vacuum cleaner wherein the rotor includes a permanent magnet having a plurality of magnetic poles and an electrical resistivity of 10Ω·cm or less.

10. In any one of paragraphs 1 to 9, A vacuum cleaner wherein the fan motor includes a metal cover surrounding an outer surface of the rotor.

11. A shaft (13a) rotatable around a rotation axis (A); A rotor (13b) fixed to the shaft, comprising a plurality of stimuli arranged in the direction of rotation; It comprises a stator (13c) including an annular core ring (61), a plurality of protruding teeth (62) that protrude from the core ring toward the rotation axis and are arranged radially, and a plurality of coils (65) arranged on each of the plurality of teeth; Each of the above plurality of teeth includes a protrusion (66) facing the rotor with an air gap (Ga), a first flange portion (71) protruding from the protrusion (66) in the rotational direction, and a second flange portion (72) protruding in the opposite direction to the rotational direction. A fan motor in which the first flange portion and the second flange portion are asymmetrical with respect to the center line (CL) of the teeth extending from the rotation axis.

12. In paragraph 11, The above first flange portion includes a first opposing surface (75) facing the air gap and extending in the rotational direction from the center line, The above second flange portion includes a second opposing surface (76) facing the air gap and extending in the opposite direction of the rotational direction from the center line, The first gap (G1), which is the distance between the first opposing surface and the outer surface of the rotor, is constant. A fan motor in which the second gap (G2), which is the distance between the second opposing surface and the outer surface of the rotor, increases in the direction opposite to the rotational direction.

13. In paragraph 12, A fan motor in which the distance (W2) from the center line to the protruding end (72b) of the second facing surface is greater than the distance (W1) from the center line to the protruding end (71a) of the first facing surface.

14. In any one of paragraphs 11 to 13, A fan motor wherein the rotor includes a plurality of magnetic poles and a permanent magnet having an electrical resistivity of 10Ω·cm or less.

15. In any one of paragraphs 11 to 14, A fan motor comprising a metal cover surrounding an outer surface of the rotor.

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