Fan motor

Abstract

This utility model relates to a fan motor. The fan motor includes a shroud, an impeller housed within the shroud, a motor connected to the impeller via a rotating shaft, and a motor housing housing the motor. The motor housing includes an outer wall portion, an inner wall portion, a cover portion covering the upstream end of the inner wall portion, and blades disposed between the inner circumferential surface of the outer wall portion and the outer circumferential surface of the inner wall portion. A discharge flow path is formed between the inner wall portion and the outer circumferential surface of the stator. Air in the air cavity formed by the cover portion, the inner wall portion, and the upstream end of the motor is discharged through the discharge flow path due to the high air velocity passing through the blades. Thus, air inside the air cavity can be discharged to the outside without stagnation.

Description

Technical Field

[0001] This utility model relates to a fan motor, and more specifically, to a fan motor that can improve the cooling performance of the motor. Background Technology

[0002] The motor can be installed in household appliances such as vacuum cleaners or hair dryers.

[0003] Vacuum cleaners or hair dryers can use motors as a power source to generate rotational force.

[0004] For example, a motor can be mounted to a fan. The fan can receive power from the motor to rotate at high speed, thereby generating airflow.

[0005] Handheld vacuum cleaners or hair dryers operate while the user holds them directly in their hand.

[0006] To improve user portability and convenience, it is necessary to miniaturize and lighten vacuum cleaners or hair dryers.

[0007] To increase the amount of work done by the fan, you can increase the fan diameter or increase the fan speed.

[0008] To increase the motor's capacity, its diameter or axial length can be increased. This, in turn, increases the motor's capacity.

[0009] A fan motor assembly is disclosed in existing patent document KR10-2023-0072178A (hereinafter, Patent Document 1).

[0010] In the case of Patent Document 1, when the diameter of the motor (stator) is fixed and the outer diameter of the flow path section (diffuser) is increased, the flow path spacing between the outer diameter of the motor and the inner diameter of the flow path section increases.

[0011] However, in Patent Document 1, the airflow discharged from the outlet of the flow path acts as an air curtain, causing the air inside the motor housing to be unable to be discharged through the flow path interval, resulting in the phenomenon of stagnant airflow.

[0012] Therefore, Patent Document 1 suffers from a decrease in the cooling performance of the motor.

[0013] In addition, in Patent Document 1, the stator is housed inside the motor housing towards the impeller, resulting in a narrow space between the inner side of the motor housing and the stator.

[0014] Therefore, the air volume between the motor housing and the stator is insufficient to absorb the heat generated by the stator, resulting in a decrease in the motor's cooling performance.

[0015] In addition, the area of ​​the stator core exposed to the outside of the motor housing is relatively small, which leads to a decrease in heat dissipation performance.

[0016] A motor assembly and a vacuum cleaner including the motor assembly are disclosed in existing patent document KR10-2021-0153940A (hereinafter, Patent Document 2).

[0017] In the case of Patent Document 2, the motor assembly includes a heat dissipation cover that covers the outer side of the motor. The heat dissipation cover includes an inner cover and an outer cover. The inner cover is spaced apart from the outer side of the motor.

[0018] The inner cover forms an inner flow path for air to flow through the gap. The outer cover is disposed outside the inner cover. An outer flow path for air to flow is formed along the outer surface of the outer cover. Thus, the inner cover is disposed adjacent to the outer side of the motor, and air outside the housing flows through the gap along the outer side of the motor towards the interior of the housing, thereby effectively cooling the motor.

[0019] However, in Patent Document 2, in order to form the inner flow path and the outer flow path of the cover, an additional heat dissipation cover is required, which results in an increase in the number of parts and an increase in manufacturing costs. Utility Model Content

[0020] Problems to be solved by the utility model

[0021] The purpose of this invention is to provide a fan motor with a structure that can solve the above-mentioned problems.

[0022] The first objective is to provide a fan motor with a structure that can eliminate air stagnation inside the motor housing.

[0023] The second objective is to provide a fan motor with a structure that can adequately ensure the cooling performance of the motor by ensuring space for absorbing the heat generated by the motor.

[0024] The third objective is to provide a fan motor with a structure that improves heat dissipation performance by increasing the area of ​​the stator core exposed to the outside of the motor housing.

[0025] The fourth objective is to provide a fan motor structure that can effectively cool the motor by forming a recirculation flow of air moving from the outside to the inside of the motor housing without adding any components, and also reduces the number of parts and manufacturing costs.

[0026] Technical solutions to the problem

[0027] Based on in-depth research, the inventors have found that the problems of this utility model and the first to fourth objectives mentioned above can be achieved through the following embodiments of this utility model.

[0028] To achieve the first objective mentioned above, the fan motor of this invention includes: a shroud; an impeller housed within the shroud to create airflow; a rotating shaft to which the impeller is coupled; a motor housing coupled to the downstream side of the shroud; and a motor housed within the motor housing, comprising a rotor coupled to the rotating shaft and a stator surrounding the rotor, wherein the motor drives the impeller.

[0029] The motor housing includes: an outer wall portion; an inner wall portion disposed radially inside the outer wall portion; and blades disposed between the inner circumferential surface of the outer wall portion and the outer circumferential surface of the inner wall portion to guide the flow of air.

[0030] A narrow discharge path is formed between the inner wall portion and the outer peripheral surface of the stator. Air in the air cavity formed on the inner wall of the motor housing is discharged to the outside of the motor housing via the discharge path due to the high air velocity passing through the blades.

[0031] Therefore, the air in the air chamber absorbs the heat generated by the motor and is discharged to the outside of the motor housing without stagnating, thereby improving the cooling performance of the motor.

[0032] The stator includes a stator core and stator coils wound around the stator core.

[0033] The spacing of the discharge flow path can be defined as the spacing between the inner circumferential surface of the inner wall portion and the outer circumferential surface of the stator core.

[0034] The spacing of the discharge flow path can be from the thickness of the inner wall portion to the radial width of the blade. The radial width of the blade can be defined as the length of the blade extending radially from the inner circumference of the outer wall portion to the outer circumference of the inner wall portion.

[0035] Thus, the spacing of the discharge flow path results in a narrower flow path spacing between the blades and the stator, allowing the airflow through the blades to impact the outer peripheral surface of the stator at high speed.

[0036] The spacing of the discharge flow path can be 3% to 11% of the outer peripheral diameter of the outer wall or 3% to 11% of the radial outer diameter of the blade.

[0037] If the spacing of the discharge flow paths is less than the minimum value of the numerical range, the flow resistance is high, making it difficult for air to be discharged. If the spacing of the discharge flow paths is greater than the maximum value of the numerical range, the flow velocity decreases, resulting in a reduction in the suction force on the air in the air chamber.

[0038] To achieve the second and third objectives described above, the height of the air cavity can be defined as the distance between the inner side of the cover covering the upstream end of the inner wall and the upstream end of the motor. The height of the air cavity can correspond to the length between the inner side of the cover and the downstream end of the blade.

[0039] Therefore, the air cavity ensures sufficient space to accommodate air capable of absorbing the heat generated by the motor. Furthermore, by increasing the area of ​​the motor exposed to the outside of the motor housing, the motor's heat dissipation performance can be improved.

[0040] The height of the air cavity can be 22% to 42% of the radial outer diameter of the blade.

[0041] If the height of the air cavity is less than the minimum value of the range, the volume of air that the air cavity can hold decreases, which may reduce the cooling performance of the motor. If the height of the air cavity is greater than the maximum value of the range, the size (axial length) of the fan motor increases, which is not conducive to product miniaturization.

[0042] The axial distance between the inner side of the cover and the downstream end of the blade, minus the axial separation distance between the inner side of the cover and the upstream end of the stator, can be defined as the phase difference.

[0043] The range of the phase difference can be from "-the protrusion height of the insulator boss" to "+the protrusion height of the insulator boss".

[0044] The insulator boss can be formed by protruding from the insulator covering the upstream end of the stator core along the axial direction of the rotation axis.

[0045] If the phase difference is less than "-the protrusion height of the insulator boss", it is not conducive to product miniaturization. If the phase difference is greater than "+the protrusion height of the insulator boss", the amount of air contained in the air cavity is reduced, which may decrease the cooling performance of the motor.

[0046] The downstream end of the blade and the upstream end of the stator can be arranged to overlap each other radially. This results in an optimal structure for an air-cooled motor.

[0047] To achieve the fourth objective mentioned above, the stator core includes: a plurality of teeth that protrude radially from the inside of the stator core toward the center of the rotation axis; and a plurality of slots formed between the plurality of teeth, the stator coil being wound around the plurality of slots.

[0048] Air outside the motor housing can form a recirculation flow by flowing from the downstream side of the motor through the slot and moving into the air cavity.

[0049] Therefore, by increasing the exposed area of ​​the motor that can contact the air without adding any components, the motor's heat dissipation performance can be maximized. Furthermore, through the recirculation flow, the heated air in the air chamber can be replaced by the cool air outside the motor housing.

[0050] The axial distance between the inner side of the cover and the downstream end of the outer wall can be the same as the axial distance between the inner side of the cover and the downstream end of the inner wall. This improves the straightness of the airflow passing through the blades.

[0051] The axial distance between the inner side of the cover and the downstream end of the inner wall can be less than the axial distance between the inner side of the cover and the downstream end of the outer wall.

[0052] The blade includes a blade extension that extends radially from the downstream end of the blade to cover the thickness surface of the inner wall portion.

[0053] Optionally, the blade may further include a blade protrusion that extends from the blade extension toward the discharge flow path.

[0054] Therefore, a portion of the air passing through the blades can flow into the air chamber to cool the motor.

[0055] The blades may consist of level 1 blades or N-level blades (N being a natural number greater than 2) formed by separating them from each other along the direction of airflow.

[0056] Therefore, the production of the leaves is easy.

[0057] The motor housing includes a plurality of support portions, which protrude radially from the inner peripheral surface of the inner wall portion to surround the outer peripheral surface of the stator, and extend axially from the downstream end of the inner wall portion to support the stator.

[0058] Thus, the plurality of the aforementioned support portions can stably support the motor.

[0059] The plurality of said support portions are spaced apart in a circumferential direction along the outer peripheral surface of the stator, and the discharge flow path can be arranged between the plurality of said support portions that are adjacent in the circumferential direction.

[0060] Therefore, the discharge path can improve the accessibility of the air passing through the blades to the outer peripheral surface of the stator.

[0061] A motor mounting portion is recessed on the radial inner side of the support portion, and the motor mounting portion can be aligned with the motor mounting position that is axially spaced from the inner side of the cover portion.

[0062] Therefore, by indicating the starting point for motor installation, the motor mounting section can facilitate easy installation of the motor.

[0063] The motor housing may include a first inner wall portion having a first thickness and being formed in a cylindrical shape. The motor housing may also include a second inner wall portion. The second inner wall portion may be connected to the downstream side of the first inner wall portion, with reference to the airflow direction. The second inner wall portion may have a second thickness greater than the first thickness and be formed in a cylindrical shape.

[0064] The motor housing may further include an inner flow path wall portion surrounding the outer peripheral surface of the first inner wall portion. The motor housing may further include an outer flow path wall portion, which is received inside the downstream end of the housing and is radially spaced from the outer side of the inner flow path wall portion.

[0065] The motor housing may include an outer wall portion connected to the downstream end of the flow path outer wall portion and radially spaced from the outer side of the second inner wall portion.

[0066] The motor housing may include a first blade that extends protruding from the outer periphery of the inner wall of the flow path towards the outer wall of the flow path. The motor housing may include a second blade that is connected in communication with the downstream end of the first blade and extends protruding from the outer periphery of the second inner wall towards the outer wall.

[0067] Therefore, based on the airflow direction, the first blade and the second blade can be configured in a separable structure on the upstream and downstream sides, respectively. The blades are easy to manufacture.

[0068] The outer wall portion can be attached to the downstream end of the protective cover. Therefore, the attachment of the protective cover and the motor housing is easy.

[0069] The motor housing may include: a first bearing, disposed downstream of the impeller with reference to the airflow direction, and supporting the upstream side of the rotating shaft; and a first bearing housing, disposed at the center of the cover portion, for housing the first bearing.

[0070] The motor housing may further include: a second bearing, disposed downstream of the motor with respect to the airflow direction, and supporting the downstream side of the rotating shaft; and a second bearing housing for accommodating the second bearing.

[0071] This allows for stable support of the rotating shaft.

[0072] The motor housing may include: a support portion, which protrudes from the inner circumferential surface of the inner wall portion toward the rotation axis to support the outer circumferential surface of the stator; a connecting portion, which connects to the downstream end of the support portion; and a bridge portion, which extends radially to connect to the outer circumferential surface of the second bearing housing and the inner circumferential surface of the connecting portion.

[0073] Thus, the connecting portion can connect the second bearing housing to the support portion.

[0074] The fan motor may also include a control unit disposed downstream of the motor and including a PCB on which IGBTs and capacitors are mounted, the control unit controlling the operation of the motor.

[0075] The leads electrically connected to the stator can be connected to a power supply connection portion provided on the PCB. This allows power to be supplied to the stator.

[0076] The PCB is configured to face the air cavity axially.

[0077] Air discharged from the air cavity via the exhaust path can move toward the PCB to cool the IGBT and the capacitor.

[0078] Air between the downstream side of the motor and the PCB can flow through an internal flow path formed inside the motor to move into the air cavity, thereby creating a recirculation flow. This improves the cooling performance of the control unit and the motor.

[0079] Utility Model Effect

[0080] According to the embodiments of this utility model, the following effects can be achieved.

[0081] First, the motor housing includes: an outer wall portion; an inner wall portion disposed inside the outer wall portion; and blades disposed between the outer wall portion and the inner wall portion, guiding the flow of air generated by the impeller. An air cavity may be formed inside the motor housing. The air in the air cavity can absorb the heat generated by the motor. A discharge flow path is formed between the inner circumferential surface of the inner wall portion and the outer circumferential surface of the stator constituting the motor. As the diameter of the inner wall portion of the blades decreases relative to the outer circumferential surface of the stator, the spacing of the discharge flow path narrows. Thus, the air passing through the blades impacts the outer circumferential surface of the stator via the discharge flow path. The flow velocity of the air moving axially along the outer circumferential surface of the stator is faster than the flow velocity of the air in the air cavity. The high flow velocity of the air flowing along the outer circumferential surface of the stator can draw in air from the air cavity and discharge it to the outside of the motor housing. Thus, the air inside the air cavity can be discharged to the outside without stagnation.

[0082] Secondly, if the air cavity is insufficient, the space for absorbing the heat generated by the motor will decrease, potentially reducing the motor's cooling performance. Ensuring sufficient air cavity space is crucial for improving motor cooling performance. There are two methods to increase the air cavity space. One method is to increase the radius of the air cavity. However, if the inner diameter of the inner wall is increased to increase the radius of the air cavity, the spacing of the exhaust flow path becomes wider, resulting in a lower airflow velocity along the outer circumference of the stator, making it difficult to discharge the air from the air cavity to the outside via the exhaust flow path. Therefore, increasing the radius of the air cavity has limitations.

[0083] Another method is to increase the height of the air chamber. The height of the air chamber refers to the distance between the upstream end of the motor and the inner side of the motor housing. This reduces the spacing of the exhaust flow path while ensuring sufficient space in the air chamber.

[0084] An optimal motor cooling structure can be achieved when the length of the upstream end of the motor, which is axially separated from the inner side of the motor housing, corresponds to the length of the ejector portion of the blade extending axially from the inner side of the motor housing.

[0085] For example, the "phase difference" can be defined as the axial distance between the inner side of the motor housing and the downstream end of the blade, minus the axial separation distance between the inner side of the motor housing and the upstream end of the stator core. An optimal motor cooling structure can be achieved when the phase difference is 0 mm. To improve the motor's cooling performance, preferably, the phase difference is within the range of 0 mm ± the protrusion height of the insulator boss. The insulator boss is a portion of the insulator that protrudes axially from the upstream end of the stator core, isolating (electrically insulating) the ends of the stator coils from their periphery.

[0086] In addition, when the phase difference is 0 mm, the area of ​​the stator core exposed to the outside of the motor housing increases, thus maximizing the effective cooling area of ​​the motor.

[0087] Furthermore, the air outside the motor housing can directly cool the outer circumference of the stator core due to the airflow velocity through the blades.

[0088] Third, by increasing the air velocity of the air layer around the stator core through the blades, air is drawn out of the air cavity, thereby creating a recirculation flow of external air from the motor housing back into the air cavity.

[0089] Therefore, the recirculation flow can eliminate the thermal dome phenomenon caused by air stagnation in the air chamber. In addition, the recirculation flow can replace the heated air in the air chamber with cold air, thereby effectively cooling the motor. Attached Figure Description

[0090] Figure 1 This is a perspective view showing the appearance of a fan motor according to an embodiment of the present invention.

[0091] Figure 2 yes Figure 1 An exploded view of the fan motor.

[0092] Figure 3 It is used for explanation Figure 1 A cross-sectional view of the internal structure of the fan motor. Figure 3 (a) in Figure 3 The diagram on the left, with the vertical center line O-O' as the reference, shows the initial design of the fan motor. Figure 3 (b) in Figure 3 The diagram on the right, with the vertical center line O-O' as the reference, is a conceptual diagram showing the configuration of a fan motor according to an embodiment of the present invention.

[0093] Figure 4 It is used for explanation Figure 1 A cross-sectional view of the internal structure of the fan motor. Figure 4 (a) is shown with Figure 3 (a) is a conceptual diagram of the initial design form of the fan motor. Figure 4 (b) is shown to be related to Figure 3 (b) is a conceptual diagram of the configuration of a fan motor according to an embodiment of the present invention.

[0094] Figure 5 and Figure 4 (b) corresponds to a cross-sectional view showing a fan motor according to an embodiment of the present invention.

[0095] Figure 6 It is magnification Figure 5The “VI” section is a conceptual diagram showing the arrangement of the upstream end of the stator core and the ejection surface of the blades in a radially corresponding configuration.

[0096] Figure 7 It is shown Figure 1 A conceptual diagram showing the height of the protrusion of the boss in the insulator.

[0097] Figure 8 Is Figure 7 The view taken along direction VIII is a conceptual diagram showing the radius and height of the air cavity.

[0098] Figure 9 It is shown Figure 5 A conceptual diagram of the recirculation flow inside the motor housing in an embodiment.

[0099] Figure 10 It is a graph showing the temperature change of the motor based on the stator core's placement length (phase difference).

[0100] Figure 11 It shows based on Figure 10 A conceptual diagram showing the configuration relationship between the motor housing and the stator in terms of phase difference. Figure 11 (a) shows the configuration of the motor housing and stator when the phase difference is greater than 0. Figure 11 (b) shows the configuration of the motor housing and stator when the phase difference is 0.

[0101] Figure 12 It is a graph used to compare the saturation time and saturation temperature of the existing structure with the structure of this utility model that uses an air cavity. Detailed Implementation

[0102] The fan motor of the present invention will now be described in detail with reference to the accompanying drawings.

[0103] In the following description, in order to make the features of this utility model clearer, some structural elements may be omitted.

[0104] 1. Definition of Terminology

[0105] Terms containing ordinal numbers such as "first" and "second" may be used to describe a variety of constituent elements, but the constituent elements are not limited by the terms. The terms are used only for the purpose of distinguishing one constituent element from other constituent elements.

[0106] When a constituent element is referred to as "connected" or "linked" to another constituent element, it should be understood that it may be directly connected to or linked to that other constituent element, but there may also be other constituent elements between them. Conversely, if a constituent element is referred to as "directly connected" or "directly linked" to another constituent element, it should be understood that there are no other constituent elements between them.

[0107] Unless the context clearly indicates otherwise, the singular expressions used in this specification include the plural expressions.

[0108] The term "fan motor" as used in the following description can be understood as a device that uses the power of an electric motor or similar device to rotate a fan in order to draw in or deliver air.

[0109] In the following description, "axial" refers to the length direction of the axis of rotation.

[0110] In the following description, "radial" refers to the length of a line segment from the center of a circle or cylinder to a point on the circumference.

[0111] The term "circumferential direction" as used in the following description refers to the direction of the circumference.

[0112] 2. Description of the structure of a fan motor according to an embodiment of the present invention

[0113] Figure 1 This is a perspective view showing the appearance of a fan motor according to an embodiment of the present invention.

[0114] Figure 2 yes Figure 1 An exploded view of the fan motor.

[0115] Figure 3 It is used for explanation Figure 1 A cross-sectional view of the internal structure of the fan motor. Figure 3 (a) in Figure 3 The diagram on the left, with the vertical center line O-O' as the reference, shows the initial design of the fan motor. Figure 3 (b) in Figure 3 The diagram on the right, with the vertical center line O-O' as the reference, is a conceptual diagram showing the configuration of a fan motor according to an embodiment of the present invention.

[0116] Figure 4 It is used for explanation Figure 1 A cross-sectional view of the internal structure of the fan motor. Figure 4 (a) is shown with Figure 3 (a) is a conceptual diagram of the initial design form of the fan motor. Figure 4 (b) is shown to be related to Figure 3(b) is a conceptual diagram of the configuration of a fan motor according to an embodiment of the present invention.

[0117] Figure 5 and Figure 4 (b) corresponds to a cross-sectional view showing a fan motor according to an embodiment of the present invention.

[0118] The fan motor of this invention can be applied to household appliances such as handheld vacuum cleaners.

[0119] The fan motor can be mainly composed of a housing, an impeller 113, and a motor 117.

[0120] The housing forms the appearance of the fan motor. The housing includes a cover 100, a first cover, and a second cover. Here, the first cover, which houses the motor 117, can be named the motor cover 109. The housing can be formed of a plastic material.

[0121] The shroud 100 is provided with a receiving space to house the impeller 113. In addition, the receiving space of the shroud 100 can accommodate a portion of the blade 135 (described later), a portion of the motor housing 109, or the first bearing 107.

[0122] The air movement channel generated by the impeller 113 can be formed in the space between the shroud 100 and the impeller 113, as well as in the flow path section described later.

[0123] The protective cover 100 can be formed in a cylindrical shape. It should be noted that the diameter of the protective cover 100 can be formed differently along the length of the cylinder.

[0124] When observing the detailed structure of the shield 100, the shield 100 may include an intake 101, an inclined portion 102, and a straight portion 103. The detailed structural elements of the shield 100 described above can be divided in order from the upstream side to the downstream side of the shield 100, based on the direction of airflow.

[0125] The suction port 101 is located at the upstream end of the shroud 100. The suction port 101 is cylindrical. Compared with other detailed configurations of the shroud 100, the diameter of the suction port 101 is relatively small and its length is relatively short. The suction port 101 can be formed through the axial direction. One end of the impeller 113 can be accommodated inside the suction port 101.

[0126] Thus, air is drawn in through the intake port 101 by the rotation of the impeller 113.

[0127] An inclined portion 102 is provided on the downstream side of the suction port 101. The inclined portion 102 is formed at an angle relative to the rotation axis 106, such that the diameter of the inclined portion 102 gradually increases as it approaches the downstream side from the upstream side of the shield 100.

[0128] The inclined portion 102 may be formed in a conical shape along the circumference of the intake port 101. The inclined portion 102 may be formed in a curved shape. The inclined portion 102 may be formed with different curvatures as it approaches the straight portion 103 described later from the intake port 101. One part and another part of the inclined portion 102 with different curvatures may have curvatures in opposite directions to each other.

[0129] A reinforcing portion may be formed at the angle where the intake port 101 and the inclined portion 102 connect. The reinforcing portion may extend in the circumferential direction. The reinforcing portion at the connection between the intake port 101 and the inclined portion 102 prevents the thickness of the shield 100 from decreasing and increases the thickness of the shield 100, thereby improving the strength of the shield 100.

[0130] The straight section 103 is formed in a cylindrical shape. The straight section 103 is configured to connect the downstream end of the inclined section 102 and the straight section 103 described later.

[0131] The cover 100 is combined with the motor housing 109. For example, a portion of the cover 100 may be combined to enclose a portion of the motor housing 109.

[0132] Alternatively, a portion of the cover 100 may be abutted against a portion of the motor housing 109, described later, and secured using fastening components such as bolts.

[0133] The protective cover 100 may also include a first fastening part 104.

[0134] The first fastening part 104 may be provided at the downstream end of the cover 100. The first fastening part 104 is coupled to the second fastening part 134 of the motor cover 109, which will be described later.

[0135] The first fastening portion 104 extends radially outward from the downstream side of the straight portion 103. The first fastening portion 104 extends circumferentially along the downstream periphery of the straight portion 103. A plurality of first fastening holes are formed axially through the first fastening portion 104. The plurality of first fastening holes are spaced apart circumferentially.

[0136] A protrusion 105 may be formed on the outer end of the first fastening part 104 in an axial direction. The protrusion 105 may extend in a circumferential direction along the outer periphery of the first fastening part 104. The protrusion 105 surrounds the outer peripheral surface of the second fastening part 134, which will be described later.

[0137] The rotating shaft 106 is located at the center of the housing. The rotating shaft 106 extends axially through the center of the housing.

[0138] One end of the rotating shaft 106 is housed inside the protective cover 100. An impeller 113 is rotatably mounted on one end of the rotating shaft 106.

[0139] The impeller 113 includes a hub 114 and a plurality of blades 116. The impeller 113 can be in the form of a diagonal flow fan.

[0140] The hub 114 is formed in a conical shape and inclined axially to increase the diameter of the hub 114. The diameter of the hub 114 gradually increases from the upstream end to the downstream end, with reference to the direction of air movement.

[0141] A shaft engagement groove 115 can be formed inside the center portion of the upstream side of the hub 114 so that one end of the rotating shaft 106 is engaged with the center portion of the hub 114. The inner diameter of the shaft engagement groove 115 is formed correspondingly to the diameter of the rotating shaft 106, so that the shaft engagement groove 115 and the rotating shaft 106 can be pressed together.

[0142] Therefore, the diameter of the upstream end of the shaft coupling groove 115 can be smaller than the diameter of the rotating shaft 106, so that the upstream end of the rotating shaft 106 is locked in the thrust direction.

[0143] A mating hole may be formed at the upstream end of the hub 114 and the shaft mating groove 115 to allow the hub 114 and the rotating shaft 106 to be mated.

[0144] The blade 116 can be formed by protruding obliquely from the outer peripheral surface of the hub 114 at a predetermined angle relative to the radial direction. The blade 116 can extend in a spiral shape along the outer peripheral surface of the hub 114.

[0145] A plurality of blades 116 are provided. The plurality of blades 116 are arranged at predetermined intervals along the circumferential direction of the hub 114.

[0146] Thus, the impeller 113 can rotate together with the rotating shaft 106. The plurality of blades 116, which rotate at high speed together with the hub 114, rotate the air in the internal space of the shroud 100, and can draw external air into the interior of the shroud 100 through the intake port 101.

[0147] The motor housing 109 is disposed on the downstream side of the cover 100. The motor housing 109 may include a first bearing housing 110, a cover portion 112, and a flow path portion.

[0148] The rotating shaft 106 can be rotatably supported by a first bearing 107 and a second bearing 108. The first bearing 107 can be disposed on one side of the rotating shaft 106, and as an example, it can be the upstream side of the rotating shaft 106 with respect to the airflow direction.

[0149] The second bearing 108 can be configured on the other side of the rotating shaft 106. As an example of the other side, it can be the downstream side of the rotating shaft 106 with the airflow direction as a reference.

[0150] The first bearing 107 can be disposed adjacent to the impeller 113 on the downstream side of the hub 114.

[0151] Bearings 107 and 108 can be ball bearings or air bearings, etc.

[0152] A rotor 118 and a stator 119 constituting a motor 117, described later, may be disposed between the first bearing 107 and the second bearing 108.

[0153] A first bearing support portion may be formed on one side of the rotating shaft 106. The first bearing 107 may be press-fitted into the first bearing support portion.

[0154] The first bearing 107 is housed in the first bearing housing 110. The first bearing housing 110 may be cylindrical. The first bearing housing 110 may protrude toward the hub 114 from the inner side of the cover portion 112 (described later) (see reference). Figure 3 ), or protruding axially towards the motor 117 to form (see reference) Figure 4 (b) and Figure 5 The first bearing housing 110 extends circumferentially to surround the outer peripheral surface of the first bearing 107.

[0155] At one axial end of the first bearing housing 110, for example at the upstream end, a first stop 111 is formed protruding radially inward. The first stop 111 can restrict the first bearing 107 from moving in the thrust direction while it is housed in the first bearing housing 110.

[0156] For example, if the impeller 113 rotates, air is drawn into the inside of the shroud 100 through the intake port 101 and moves along the inner side of the shroud 100, flowing into the flow path section described later.

[0157] At this time, as air moves from the intake port 101 of the shroud 100 toward the first axial direction toward the first fastening part 104, according to the law of action and reaction, a thrust is generated in the second axial direction opposite to the first axial direction. The thrust can act on the rotating shaft 106 and the impeller 113.

[0158] Accordingly, the first stop 111 restricts the first bearing 107, which is coupled to the rotating shaft 106, from moving in the direction of the thrust under the action of the thrust.

[0159] The cover portion 112 may be formed in the shape of a disc. The cover portion 112 may extend radially from the outer periphery of the first bearing housing 110 toward the upstream end of the inner wall portion 130 of the flow path portion, which will be described later. The cover portion 112 may extend circumferentially along the outer periphery of the first bearing housing 110.

[0160] The cover portion 112 connects the first bearing housing 110 and the flow path portion. The radially inner side of the cover portion 112 surrounds the outer peripheral surface of the first bearing housing 110. The radially outer side of the cover portion 112 is connected to one end of the inner wall portion 130 of the flow path portion.

[0161] Here, the radially inner side of the cover 112 refers to one end of the cover 112 that faces the rotation axis 106 radially. The radially outer side of the cover 112 refers to the other end of the cover 112 that faces the rotation axis 106 radially in the opposite direction.

[0162] The cover 112 may form one side of the motor housing, which will be described later. As an example of such a side, it may be the inner side of the motor housing 109 that faces the rotor 118 and stator 119 of the motor 117 axially.

[0163] The motor housing 109 may include an inner wall portion 130, an outer wall portion 133, and blades 135 to form a flow path portion.

[0164] The inner wall portion 130 is formed into a cylindrical shape with a first diameter. One axial end of the inner wall portion 130 is connected to the outer end of the cover portion 112. Here, the axial direction of the inner wall portion 130 refers to the length direction of the inner wall portion 130.

[0165] The inner wall portion 130 can be formed together with the cover portion 112 to form a motor receiving portion on the inner side. The motor receiving portion can be disposed on the inner side of the inner wall portion 130, and the flow path portion can be disposed on the outer side of the inner wall portion 130.

[0166] The outer wall portion 133 and the inner wall portion 130 are arranged radially apart on their outer peripheral surfaces. The outer wall portion 133 is formed into a cylindrical shape having a second diameter that is larger than the first diameter.

[0167] The upstream end of the outer wall portion 133 can be accommodated inside the downstream end of the cover 100. The upstream end of the outer wall portion 133 and the downstream end of the cover 100 can be joined together.

[0168] The outer wall portion 133 may also include a second fastening portion 134.

[0169] The second fastening portion 134 can be formed by protruding radially outward from the upstream end of the outer wall portion 133. The second fastening portion 134 can extend circumferentially along the outer periphery of the outer wall portion 133. A plurality of second fastening holes are formed through the second fastening portion 134 axially.

[0170] A plurality of second fastening holes are arranged circumferentially spaced in the second fastening part 134. The first fastening holes and the second fastening holes are arranged axially overlapping. Fastening components such as bolts can be fastened by passing through the first fastening holes and the second fastening holes.

[0171] The outer wall portion 133 can be combined with the cover 100 to form the appearance of the fan motor.

[0172] An airflow passage is formed between the outer wall portion 133 and the inner wall portion 130. The airflow passage is located on the downstream side of the cover 100. When the cover 100 and the motor housing 109 are viewed axially, the airflow passage is located inside the cover 100.

[0173] Air drawn in by impeller 113 moves from shroud 100 to flow path section. The flow of air moving to flow path section can be named main flow.

[0174] A plurality of blades 135 are provided between the inner wall portion 130 and the outer wall portion 133. The blades 135 are formed to protrude radially from the outer peripheral surface of the inner wall portion 130 to the inner peripheral surface of the outer wall portion 133. The blades 135 may be formed at a predetermined angle relative to the axial direction between the inner wall portion 130 and the outer wall portion 133.

[0175] One radial end of the blade 135 is connected to the outer peripheral surface of the inner wall portion 130, and the other radial end of the blade 135 is connected to the inner peripheral surface of the outer wall portion 133.

[0176] The blade 135 is curved relative to the axial direction, with the outer peripheral surface of the inner wall portion 130 or the inner peripheral surface of the outer wall portion 133 inclined. The curvature of the blade 135 can vary along the axial direction. For example, the curvature of the blade 135 can increase as it moves from the upstream side of the flow path to the downstream side.

[0177] Thus, the blades 135 guide the airflow generated by the impeller 113 in one direction. For example, a plurality of blades 135 can convert the rotational flow of air rotating in the circumferential direction of the impeller 113 into axial flow to maintain smooth airflow.

[0178] The blade 135 can be implemented as a first-stage blade or an N-stage blade (N is a natural number greater than 2) from the upstream side to the downstream side of the motor housing 109, based on the direction of air flow.

[0179] A first-stage blade refers to a blade 135 integrally formed along the outer circumferential surface of the inner wall portion 130 or the inner circumferential surface of the outer wall portion 133 in an axial direction. An N-stage blade refers to a plurality of blades 135 formed separately from each other along the outer circumferential surface of the inner wall portion 130 or the inner circumferential surface of the outer wall portion 133 in an axial direction.

[0180] In this embodiment, a two-stage blade 135 is shown.

[0181] The second-stage blade 135 may be composed of a first blade 1352 disposed on the upstream side of the flow path and a second blade 1353 disposed on the downstream side of the flow path.

[0182] Here, the flow path section refers to the portion in which the blade 135 is formed. The axial length of the flow path section can refer to the axial length of the blade 135.

[0183] The flow path section can be configured to be divided into a first flow path section and a second flow path section. The first flow path section is arranged on the upstream side of the flow path section based on the air flow direction. A plurality of first blades 1352 are provided on the inner side of the first flow path section.

[0184] The second flow path is positioned downstream of the flow path section, based on the airflow direction. A plurality of second blades 1353 are provided inside the second flow path section.

[0185] The radial width of the flow path in each of the first and second flow paths can be configured to remain constant along the axial direction or to be different from each other. In this embodiment, the case where the radial width W of the flow path remains constant is shown.

[0186] The thickness of the inner wall portion 130 may be different along the axial direction. The inner wall portion 130 may be divided into a first inner wall portion 131 and a second inner wall portion 132 depending on the position of the flow path portion. The first inner wall portion 131 is disposed in the first flow path portion.

[0187] The second inner wall portion 132 is disposed in the second flow path portion. For example, the thickness of the first inner wall portion 131 is less than the thickness of the second inner wall portion 132.

[0188] The sum of the thicknesses of the first inner wall portion 131 and the flow path inner wall portion 136 of the flow path cover (described later) can correspond to the thickness of the second inner wall portion 132.

[0189] The motor housing 109 may also include a flow path housing.

[0190] A flow path cover is disposed on the first flow path section. The flow path cover can form the first flow path section. The flow path cover includes an inner flow path wall section 136, an outer flow path wall section 137, and a first blade 1352.

[0191] The inner wall portion 136 of the flow path is formed in a cylindrical shape. The inner wall portion 136 of the flow path has an axial length corresponding to the axial length of the first inner wall portion 131. The inner wall portion 136 of the flow path extends in a circumferential direction along the outer periphery of the first inner wall portion 131.

[0192] The inner wall portion 136 of the flow path surrounds the outer peripheral surface of the first inner wall portion 131. The inner wall portion 136 of the flow path and the first inner wall portion 131 are joined together such that the inner peripheral surface of the inner wall portion 136 and the outer peripheral surface of the first inner wall portion 131 abut against each other. The inner wall portion 136 of the flow path and the first inner wall portion 131 are arranged to overlap each other radially.

[0193] The outer peripheral surfaces of the inner wall portion 136 and the second inner wall portion 132 can be formed on the same surface along the length direction (axial direction) of the inner wall portion 136 and the second inner wall portion 132. This minimizes airflow resistance.

[0194] A bent portion 138 is formed by bending the upstream end of the inner wall portion 136 toward the outer periphery of the cover portion 112. A recessed groove 139 is formed in the corner portion of the cover portion 112 that connects with the first inner wall portion 131. The recessed groove 139 is formed by recessing from the outer periphery of the cover portion 112 toward the radially inward side.

[0195] Therefore, a bend 138 is incorporated into the recessed groove 139. The inner circumferential surface of the flow path inner wall 136 and the outer circumferential surface of the first inner wall 131 can be tightly joined together. The bend 138 is disposed adjacent to the downstream end of the hub 114, and the hub 114 and the bend 138 can be formed into streamlined curved surfaces. During the movement of air from the hub 114 to the bend 138, flow resistance can be minimized.

[0196] The outer wall portion 137 of the flow path is formed in a cylindrical shape. The outer wall portion 137 of the flow path has an axial length corresponding to the axial length of the inner wall portion 136 of the flow path. The outer wall portion 137 of the flow path is arranged radially outward from the outer peripheral surface of the inner wall portion 136 at predetermined intervals.

[0197] The outer wall portion 137 of the flow path extends circumferentially along the outer periphery of the plurality of first blades 1352. The thickness of the outer wall portion 137 of the flow path can be less than the thickness of the straight portion 103 of the shield 100. The thickness of the outer wall portion 137 of the flow path can be less than the thickness of the outer wall portion 133.

[0198] The outer wall portion 137 of the flow path can be coupled to the inner peripheral surface of the straight portion 103 of the cover 100. For this purpose, a coupling groove is formed in the radially outward recess of the inner peripheral surface of the straight portion 103. The coupling groove extends in the circumferential direction along the inner periphery of the straight portion 103.

[0199] Therefore, the outer wall portion 137 of the flow path is engaged in the mating groove, thus restricting the movement of the outer wall portion 137 of the flow path in the thrust direction. The flow path cover can be engaged and supported between the first inner wall portion 131 of the motor cover 109 and the straight portion 103 of the protective cover 100.

[0200] The inner circumferential surface of the outer wall portion 137 and the inner circumferential surface of the outer wall portion 133 can form the same surface along the length direction of the outer wall portion 137 and the outer wall portion 133.

[0201] A plurality of first blades 1352 are disposed between the inner wall portion 136 and the outer wall portion 137 of the flow path. The plurality of first blades 1352 are arranged circumferentially along the outer peripheral surface of the inner wall portion 136 or the inner peripheral surface of the outer wall portion 137 of the flow path. The inner side of the first blade 1352 is connected to the inner wall portion 136 of the flow path, and the outer side of the first blade 1352 is connected to the outer wall portion 137 of the flow path.

[0202] The first blade 1352 has a curved shape relative to the axial tilt of the outer peripheral surface of the inner wall portion 136 of the flow path or the inner peripheral surface of the outer wall portion 137 of the flow path.

[0203] The inner wall portion 136, the outer wall portion 137, and the first blade 1352 of the flow path cover can form a first flow path portion.

[0204] The second inner wall portion 132, the outer wall portion 133, and the second blade 1353 can form a second flow path portion.

[0205] The outer wall portion 133 is disposed downstream of the flow path outer wall portion 137. The outer wall portion 133 is disposed at a predetermined interval on the outer side of the second inner wall portion 132.

[0206] Taking the inner side of the motor housing 109, i.e., the inner side of the cover 112, as a reference, the sum of the axial lengths (heights) of the flow path outer wall portion 137 and the outer wall portion 133 can be the same as the sum of the axial lengths (heights) of the first inner wall portion 131 and the second inner wall portion 132 (see reference). Figure 4 (b) Figure 5 , Figure 9 Alternatively, it may be longer than the sum of the axial lengths (heights) of the first inner wall portion 131 and the second inner wall portion 132 (see reference). Figure 3 , Figure 7 , Figure 8 ).

[0207] Reference Figure 4 (b) Figure 5 , Figure 9 When the sum of the axial lengths of the first inner wall portion 131 and the second inner wall portion 132 is the same as the sum of the axial lengths of the outer wall portion 137 and the outer wall portion 133 of the flow path, the axial straightness of the air guided by the blade 135 can be improved. In addition, it is more effective for the recirculation flow described later.

[0208] Reference Figure 3 , Figure 7 as well as Figure 8When the sum of the axial lengths of the first inner wall portion 131 and the second inner wall portion 132, based on the inner side surface of the cover portion 112, is less than the sum of the axial lengths of the outer wall portion 137 and the outer wall portion 133 of the flow path, an opening may be formed radially at the downstream end of the second inner wall portion 132. Through the opening, a blade extension portion 140 and a blade protrusion portion 141 may also be provided on the second blade 1353.

[0209] The blade extension 140 can extend radially inward from the downstream end 1351 of the second blade 1353 to cover the thickness surface of the downstream end of the second inner wall portion 132. The blade protrusion 141 can be formed to protrude radially inward from the inner end of the blade extension 140 than the inner circumferential surface of the second inner wall portion 132.

[0210] The blade extension 140 and the blade protrusion 141 can change the flow direction of air discharged from the discharge end 1351, which is the downstream end of the second blade 1353, from axial towards the upstream space of the motor 117 to radially inward. As a result, the flow resistance of the air discharged from the discharge end of the second blade 1353 can be minimized.

[0211] The second fastening portion 134 protrudes radially outward from the upstream end of the outer wall portion 133. The second fastening portion 134 may extend circumferentially along the outer periphery of the outer wall portion 133. The first fastening portion 104 and the second fastening portion 134 may be arranged to overlap axially.

[0212] A second fastening hole is formed through the second fastening portion 134 along the axial direction. A plurality of second fastening holes are provided in the second fastening portion 134. The plurality of second fastening holes are arranged circumferentially spaced along the periphery of the second fastening portion 134. The second fastening holes overlap with the first fastening holes along the axial direction.

[0213] Thus, fastening components such as bolts pass through the first fastening hole and the second fastening hole and are connected to the first fastening part 104 and the second fastening part 134. The second fastening part 134 is connected to the downstream side of the first fastening part 104. The protective cover 100 and the motor cover 109 can be fastened by a plurality of fastening components.

[0214] A plurality of second blades 1353 are disposed between the second inner wall portion 132 and the outer wall portion 133. The number of first blades 1352 and the number of second blades 1353 may be different from each other. The inner side of the second blade 1353 is connected to the second inner wall portion 132, and the outer side of the second blade 1353 is connected to the outer wall portion 133.

[0215] The first flow path and the second flow path are connected to each other along the axial direction.

[0216] The downstream end of the first blade 1352 and the upstream end of the second blade 1353 can be separated from each other by a gap. As a result, the air moving along the first blade 1352 and the air moving along the second blade 1353 can flow continuously and smoothly without interruption.

[0217] The motor receiving portion that houses the motor 117 is located radially inside the inner wall portion 130.

[0218] To support the motor 117, a support portion 142 is provided on the inner peripheral surface of the inner wall portion 130. The support portion 142 is formed by protruding radially inward from the inner peripheral surface of the inner wall portion 130.

[0219] A plurality of support portions 142 are provided on the inner peripheral surface of the inner wall portion 130. The plurality of support portions 142 can be arranged at predetermined intervals along the inner peripheral surface of the inner wall portion 130 in a circumferential direction. In this embodiment, three support portions 142 are arranged at equal intervals of 120 degrees.

[0220] A discharge passage 144 is formed between a plurality of adjacent support portions 142 along the circumferential direction. The discharge passage 144 may be formed radially through the downstream end of the motor housing 109. The discharge passage 144 may be connected in communication with the flow passage portion.

[0221] Therefore, the stator core 120 can be exposed to the outside of the motor housing 109 through the discharge flow path 144. In addition, the stator core 120 can be in contact with the air passing through the blades 135 or with the air outside the motor housing 109 through the discharge flow path 144, thereby dissipating the heat generated by the stator core 120.

[0222] The support portion 142 extends axially on the inner circumferential surface of the inner wall portion 130.

[0223] The support portion 142 may extend axially from the downstream end of the second inner wall portion 132. The support portion 142 surrounds the outer peripheral surface of the stator core 120, which will be described later.

[0224] The axial length of the support part 142 is greater than the axial length of the stator core 120.

[0225] The motor 117 may include a rotating shaft 106, a rotor 118, and a stator 119.

[0226] The rotating shaft 106 is disposed at the center of each of the protective cover 100, the motor cover 109, and the second cover (described later). The rotating shaft 106 extends axially through the centerline of the centers of the protective cover 100, the motor cover 109, and the second cover.

[0227] A first bearing support portion is formed on one side of the rotating shaft 106 for the first bearing 107 to be press-fitted. A second bearing support portion is formed on the other side of the rotating shaft 106 for the second bearing 108 to be press-fitted.

[0228] The rotor 118 is disposed between the first bearing support and the second bearing support. A rotor support is disposed between the first bearing support and the second bearing support. The rotor 118 includes a permanent magnet. The rotor 118 may also optionally include a rotor core.

[0229] The permanent magnet can be attached to the rotating shaft 106 or to the rotor core. In this embodiment, a rotor support portion of the rotating shaft 106 is shown where the rotor core is omitted in order to achieve miniaturization of the motor 117.

[0230] The stator 119 surrounds the rotor 118, for example, a permanent magnet. The permanent magnet is radially spaced from the stator 119 by a predetermined air gap and is rotatably mounted.

[0231] The stator 119 includes a stator core 120 and a stator coil 123. The stator core 120 includes a back yoke, a plurality of teeth 121, and a plurality of slots 122. The back yoke may be formed in a ring shape.

[0232] A plurality of teeth 121 are formed by protruding radially inward from the inner circumferential surface of the back yoke towards the rotation axis 106. The plurality of teeth 121 are arranged circumferentially along the periphery of the inner circumferential surface of the back yoke. A groove 122 is formed between two adjacent teeth 121 in the circumferential direction.

[0233] The slot 122 is formed through the stator core 120 along the axial direction. A plurality of teeth 121 and a plurality of slots 122 are arranged alternately along the circumferential direction.

[0234] The stator coil 123 can be composed of a plurality of three-phase coils. The stator coil 123 is wound around the teeth 121. An insulator 124 is provided between the stator coil 123 and the stator core 120 to achieve electrical insulation.

[0235] The slot 122 can form an internal flow path for cooling the motor 117. Air can flow through the internal flow path to cool the motor 117.

[0236] A power supply lead 125 extends axially on one side of the stator coil 123. The lead 125 can receive external power through the power connection portion 126 described later.

[0237] With this configuration, if an alternating current or other power source is applied to the stator coil 123, a magnetic field is generated around the stator coil 123. Under the electromagnetic interaction between the rotor 118 and the stator 119, the rotor 118 rotates relative to the stator 119. The permanent magnet and the rotating shaft 106 rotate together to generate rotational force.

[0238] The impeller 113, which is attached to one side of the rotating shaft 106, rotates under the action of the rotational force transmitted through the rotating shaft 106.

[0239] The stator core 120 is pressed into and joined to a plurality of support portions 142. Thus, the plurality of support portions 142 can support the stator 119.

[0240] A motor mounting portion 143 is provided on the inner side of the support portion 142. The motor mounting portion 143 is formed radially recessed on the inner side of the support portion 142. The circumferential width of the support portion 142 is smaller than the interval between the plurality of support portions 142.

[0241] The inner surface of the motor mounting section 143 can be formed into a curved surface shape with a curvature corresponding to the outer peripheral surface of the stator core 120.

[0242] Thus, the motor mounting portion 143 can surround and make surface contact with the outer peripheral surface of the stator core 120. A stepped portion is formed at one axial end of the motor mounting portion 143; for example, a stepped portion is formed at the upstream end of the motor mounting portion 143. The stepped portion aligns the axial position of the stator core 120.

[0243] The stepped portion forms a radial stepped surface at the boundary line between the support portion 142 and the motor mounting portion 143. The stepped portion may cover a portion of one axial end of the stator core 120.

[0244] Therefore, when the stator core 120 is pressed into and engaged between the plurality of support portions 142, one axial end of the stator core 120 can be locked against the stepped portion. The stepped portion can restrict the movement of the stator core 120 in the thrust direction while engaged with the support portion 142. Thus, the engagement position of the stator core 120 can be aligned by the stepped portion.

[0245] The second cover is located downstream of the motor cover 109. The second cover includes a second bearing cover 145, a bridge portion 147, and a connecting portion 148.

[0246] The second bearing 108 is housed in the second bearing housing 145. The second bearing housing 145 may be formed in a cylindrical shape. The second bearing housing 145 extends circumferentially to surround the outer peripheral surface of the second bearing 108.

[0247] The second stop 146 protrudes radially inward from one axial end of the second bearing housing 145. Here, the axial end of the second bearing housing 145 refers to the first axial end in the direction of air flow between the two axial ends of the second bearing housing 145.

[0248] Thus, the second stop 146 can restrict the second bearing 108 from moving along the first axial direction while it is housed in the second bearing housing 145.

[0249] The bridge portion 147 extends radially from the outer peripheral surface of the second bearing housing 145 toward the inner surface of the connecting portion 148 (described later). A plurality of bridge portions 147 may be provided. The plurality of bridge portions 147 may be arranged circumferentially along the outer periphery of the second bearing housing 145. Thus, the bridge portions 147 can connect the second bearing housing 145 and the connecting portion 148.

[0250] The connecting portion 148 can be formed by protruding from the outer end of the bridge portion 147 toward the downstream end of the support portion 142. The connecting portion 148 can be engaged with the downstream end of the support portion 142. The connecting portion 148 can surround the downstream end of the support portion 142. For example, a support receiving groove 149 can be formed axially recessed at one end of the connecting portion 148.

[0251] The support receiving groove 149 may include a first surface, a second surface, and a third surface. The first surface of the support receiving groove 149 may be formed facing the downstream end of the support 142 axially.

[0252] The second surface of the support receiving groove 149 can extend axially from one end of the first surface and is configured to face one of the two circumferentially facing sides of the support 142. The third surface of the support receiving groove 149 can face the other of the two circumferentially facing sides of the support 142.

[0253] The downstream end of the support portion 142 is inserted into the support portion receiving groove 149 that is coupled to the joint portion 148. Alternatively, the support portion 142 and the joint portion 148 may also be fastened using fastening members such as bolts.

[0254] A control unit can be arranged on the downstream side of the second housing. The control unit controls the overall operation of the fan motor, such as the motor 117. The control unit includes a printed circuit board 153, an IGBT (Insulated Gate Bipolar Transistor) 128, and a capacitor 129, etc.

[0255] A power connection portion 126 is provided on the printed circuit board 153. The power connection portion 126 protrudes from the printed circuit board 153 and is connectable to the lead 125. A plurality of power connection portions 126 are provided corresponding to the lead 125. The power connection portion 126 is connected to an external power source.

[0256] Therefore, an external power source can be applied to the stator coil 123 through the power connection 126 and the lead wire 125.

[0257] The outer peripheral surface of the stator core 120 and the inner peripheral surface of the inner wall portion 130 are separated radially by a predetermined interval through the radial thickness of the support portion 142. The predetermined interval can form a discharge flow path 144.

[0258] The discharge flow path 144 is a flow path for discharging air from the air pocket 150 (described later) to the outside of the motor housing 109. The discharge flow path 144 can be connected in communication with the flow path section.

[0259] The spacing of the discharge flow path 144 can be an important factor in determining the cooling performance of the motor 117.

[0260] This is because if the interval is too large (wide), the air passing through the second blade 1353 will act as an air curtain, causing air in the motor housing to stagnate inside the motor housing 109. Conversely, if the interval is too small (narrow), the flow resistance will increase, potentially preventing air in the motor housing from being discharged to the outside through the discharge path 144.

[0261] To address this issue, the minimum spacing of the discharge flow path 144 can be greater than or equal to the thickness of the inner wall portion 130 or the outer wall portion 133. Furthermore, the maximum spacing of the discharge flow path 144 can be less than or equal to the flow path spacing between the outer peripheral surface of the inner wall portion 130 and the inner peripheral surface of the outer wall portion 133.

[0262] At this time, the thicknesses of the inner wall portion 130 and the outer wall portion 133 can be the same. The thicknesses of the inner wall portion 130 and the outer wall portion 133 can be less than or equal to the flow path spacing between the outer peripheral surface of the inner wall portion 130 and the inner surface of the outer wall portion 133.

[0263] In this specification, except for the first inner wall portion 131 and the second inner wall portion 132 which are distinguished separately, the description of the inner wall portion 130 can be applied to both the first inner wall portion 131 and the second inner wall portion 132.

[0264] Figure 3 (a) and Figure 4 The outer diameter D of motor 17 in comparative example (a) o and Figure 3 (b) and Figure 4 (b) The outer diameter d of the motor 117 in this embodiment o They are the same. Figure 3 (a) and Figure 4 The radial width of blade 35 in comparative example (a) is... Figure 3(b) and Figure 4 In embodiment (b), the radial widths of the blades 135 are the same.

[0265] but, Figure 3 (b) and Figure 4 (b) In this embodiment, the inner diameter of the inner wall portion 130 of the motor housing 109 is smaller than... Figure 3 (a) and Figure 4 The inner diameter of the inner wall portion 30 of the motor housing 9 in the comparative example of (a). Figure 3 (b) and Figure 4 (b) In this embodiment, the outer diameter of the outer wall portion 133 of the motor housing 109 is smaller than that of the outer wall portion 133. Figure 3 (a) and Figure 4 The outer diameter of the outer wall portion 33 of the motor housing 9 in the comparative example of (a).

[0266] Figure 3 (a) and Figure 4 (a) is used in conjunction with this utility model. Figure 3 (b) and Figure 4 (b) provides a comparative example for comparison. See also... Figure 3 (a) and Figure 4 (a) shows the case where the spacing G1 of the discharge flow path 44 in the comparative example is greater than the flow path spacing G2 between the outer peripheral surface of the inner wall portion 30 and the inner peripheral surface of the outer wall portion 33.

[0267] The air velocity passing through blade 135 is greater than the air velocity inside the motor housing 109. According to Bernoulli's equation, if the air velocity is high, the air pressure is low.

[0268] However, as shown in the comparative example, when the gap G1 of the discharge flow path 44 is too large, even if the air velocity passing through the blade 35 is relatively fast, the velocity of the air flow layer adjacent to the outer peripheral surface of the stator core 20 is relatively low compared to the air velocity passing through the blade 35.

[0269] Therefore, the airflow velocity in the airflow layer adjacent to the outer peripheral surface of the stator core 20 is low, which limits the generation of low pressure sufficient to draw air from the inside of the motor housing 9 to the outside of the motor housing 9.

[0270] Conversely, this embodiment Figure 3 (b) and Figure 4(b) The minimum spacing g1 of the discharge flow path 144 may be greater than or equal to the thickness t of the inner wall portion 130 or the outer wall portion 133. Furthermore, the maximum spacing g1 of the discharge flow path 144 may be less than or equal to the flow path spacing g2 between the outer peripheral surface of the inner wall portion 130 and the inner peripheral surface of the outer wall portion 133. The maximum spacing g1 of the discharge flow path 144 may be less than or equal to the radial width g2 of the blade 135.

[0271] In this embodiment, the interval of the discharge flow path 144, that is, the interval d1 between the outer peripheral surface of the stator core 120 and the inner peripheral surface of the inner wall portion 130, is preferably 3% to 11% of the outer diameter of the outer wall portion 133 of the motor cover 109.

[0272] This is because if the spacing of the discharge flow path 144 is less than 3% of the outer diameter of the outer wall portion 133, there is a problem that air cannot be discharged smoothly due to the flow resistance of the discharge flow path 144. If the spacing of the discharge flow path 144 exceeds 11%, the flow velocity of the air flow layer adjacent to the outer peripheral surface of the stator core 120 decreases, thereby reducing the suction force of the air in the discharge flow path 144.

[0273] According to this embodiment, the interval of the discharge flow path 144, that is, the interval between the outer peripheral surface of the stator core 120 and the inner peripheral surface of the inner wall portion 130, is reduced, and the velocity of the air flow layer adjacent to the outer peripheral surface of the stator core 120 is significantly faster than the air flow velocity inside the motor housing 109.

[0274] Therefore, as the air pressure adjacent to the outer peripheral surface of the stator core 120 is significantly lower than the air pressure inside the motor housing 109, the air inside the motor housing 109 can be drawn out to the outside of the motor housing 109 and discharged through the discharge flow path 144.

[0275] In addition, the low pressure of the air adjacent to the outer peripheral surface of the stator core 120 provides suction for drawing air out of the motor housing 109, which can serve as the power source for the recirculation flow described later.

[0276] In addition, the heat dome phenomenon, which causes stagnation of hot air flow on the upstream side of motor 117, can be eliminated.

[0277] Figure 6 It is magnification Figure 5 The “VI” section is a conceptual diagram showing the arrangement of the upstream end 1201 of the stator core 120 and the ejection surfaces of the blades 135 arranged radially in correspondence with each other.

[0278] Figure 7 It is shown Figure 1 A conceptual diagram showing the height of the protrusion of the boss portion of insulator 124.

[0279] Figure 8 Is Figure 7 The view taken along direction VIII is a conceptual diagram showing the radius r and height of the air cavity 150.

[0280] The upstream end 1201 of the motor 117 is axially spaced from the inner side of the motor housing 109 by a predetermined interval. Here, the inner side of the motor housing 109 refers to the inner side of the cover 112. The inner side of the motor housing 109 and the upstream end 1201 of the motor 117 are axially facing each other. Furthermore, the upstream end 1201 of the motor 117 refers to the upstream end 1201 of the stator coil 123 and / or the stator core 120.

[0281] The insulator 124 includes insulator ends 1241 and 1242 and insulator bosses 1243 and 1244. The insulator ends 1241 and 1242 include a first insulator end 1241 covering the upstream end 1201 of the stator core 120 and a second insulator end 1242 covering the downstream end of the stator core 120.

[0282] The insulator ends 1241 and 1242 can be formed in a disk shape.

[0283] The insulator bosses 1243 and 1244 are provided in a plurality of each of the first insulator end 1241 and the second insulator end 1242. The insulator bosses 1243 and 1244 may be formed in a plurality of both the inner and outer sides of the insulator ends 1241 and 1242, respectively, with respect to the stator coil 123.

[0284] The plurality of insulator bosses 1243, 1244 may include a plurality of inner insulator bosses 1243 protruding axially along the radially inner side of the insulator ends 1241, 1242 and a plurality of outer insulator bosses 1244 protruding axially along the radially outer side of the insulator ends 1241, 1242.

[0285] The plurality of inner insulator bosses 1243 and the plurality of outer insulator bosses 1244 can be arranged apart along the circumferential direction of the insulator ends 1241, 1242.

[0286] The inner insulator boss 1243 is disposed between the permanent magnet and the stator coil 123. The outer insulator boss 1244 is disposed between the stator coil 123 and the inner wall portion 130.

[0287] Therefore, the insulator bosses 1243 and 1244 can isolate the stator coil 123 from its surroundings to prevent the magnetic field generated by the stator coil 123 from affecting the surroundings.

[0288] by Figure 7 and Figure 8 Based on this, the boss protrudes upward at the insulator ends 1241 and 1242. The protrusion height of the boss can be varied according to the amount and thickness of the stator coil 123 winding. For example, the height of the boss can be in the range of 2 to 5 mm.

[0289] The axial distance between the inner side of the motor housing 109 and the upstream end 1201 of the motor 117 is an important factor determining the cooling performance of the motor 117.

[0290] The air inside the motor housing 109 can absorb the heat generated by the stator coil 123 and the upstream end 1201 of the stator core 120.

[0291] When the radius r of the air cavity 150 is constant, the larger (wider) the axial distance between the inner side of the motor housing 109 and the upstream end 1201 of the motor 117, the greater the volume of the air cavity 150 that can absorb the heat generated by the motor 117.

[0292] The air cavity 150 forms at least a portion of the motor housing. The air cavity 150 may be formed by the inner side surface of the cover portion 112 and the inner peripheral surface of the inner wall portion 130. The volume V of the air cavity 150 may be πr. 2 ×h. Here, r is the radius r of the air cavity 150. h is the height h of the air cavity 150.

[0293] The radius r of the air cavity 150 refers to the distance from the centerline passing through the center of the rotation shaft 106 along the axial direction to the inner circumferential surface of the inner wall portion 130. The height h of the air cavity 150 refers to the axial distance between the inner side surface of the motor housing 109 and the upstream end 1201 of the motor 117.

[0294] More specifically, the height h of the air cavity 150 can refer to the axial distance between the inner side of the motor housing 109 and the upstream end 1201 of the stator core 120.

[0295] Therefore, with the diameter of the air cavity 150 constant, in order to improve the cooling performance of the motor 117, it is preferable to increase the axial distance between the inner side of the motor housing 109 and the upstream end 1201 of the stator core 120.

[0296] Preferably, the upstream end 1201 of the motor 117 is axially spaced from the inner side of the motor housing 109 and is disposed corresponding to the discharge portion of the blade 135. The discharge portion of the blade 135 refers to the downstream end 1351 of the blade 135.

[0297] More specifically, the placement length of the stator core 120 corresponds to the axial distance from the inner side of the motor housing 109 to the downstream end 1351 of the blade 135 (see reference). Figure 6 ).

[0298] In this embodiment, the height h of the air cavity 150 can be 22% to 42% of the outer diameter of the entire blade 135 or the outer diameter of the outer wall portion 133.

[0299] If the height h of the air cavity 150 is much less than 22%, the volume of the air cavity 150 that can absorb the heat of the motor 117 will decrease, and the cooling performance of the motor 117 may decrease. If the height h of the air cavity 150 is much greater than 42%, the cooling performance of the motor 117 will improve, but the axial length of the fan motor will increase, which may have an adverse effect on the miniaturization of the fan motor.

[0300] In this embodiment, the phase difference ΔD refers to the axial distance between the inner side of the motor housing 109 and the downstream end 1351 of the blade 135, minus the axial distance between the inner side of the motor housing 109 and the upstream end 1201 of the stator core 120. When the phase difference ΔD is 0 mm, the optimal cooling structure for the motor 117 can be achieved.

[0301] The phase difference ΔD can be greater than or equal to 0 mm + the height of the insulator bosses 1243 and 1244, and can be less than or equal to 0 mm - the height of the insulator bosses 1243 and 1244.

[0302] Effective cooling area refers to the area cooled by the direct impact of airflow through blades 135 on the outer periphery of motor 117, such as stator core 120.

[0303] According to the configuration of this embodiment, when the height h of the air cavity 150 and the phase difference ΔD are respectively limited to the numerical ranges described above, the effective cooling area is maximized, thereby improving the cooling effect of the motor 117.

[0304] Furthermore, the air in the air cavity 150 absorbs heat from the upstream end of the motor 117, particularly the upstream end 1201 of the stator coil 123 and the stator core 120, thereby reducing the maximum saturation temperature. In other words, the cooling performance is improved.

[0305] In addition, the air in the air chamber 150 absorbs the heat source of the motor 117, thereby delaying the time to reach the maximum saturation temperature.

[0306] Ultimately, the air in the air chamber 150 prevents the temperature of the motor 117 from rising sharply, thereby improving the reliability of products such as vacuum cleaners.

[0307] Figure 9It is shown Figure 5 A conceptual diagram of the recirculation flow inside the motor housing 109 of an embodiment.

[0308] In this embodiment, the airflow can be divided into a main flow and a recirculation flow. The main flow can be designated as the first flow ①. The recirculation flow can be designated as the second flow ②.

[0309] As described above, the main flow can be formed by the impeller 113. As the impeller 113 rotates, external air flows into the interior of the shroud 100 through the intake port 101.

[0310] The air flowing into the shroud 100 moves towards the flow path section along the flow path between the outer peripheral surface of the impeller hub 114 and the inner peripheral surface of the shroud 100.

[0311] Air flowing along the flow path between the outer peripheral surface of the inner wall portion 130 and the inner peripheral surface of the outer wall portion 133 formed in the flow path portion is guided by the blade 135 and discharged from the downstream end 1351 of the blade 135, i.e., the discharge portion.

[0312] Because the flow path spacing between the inner circumferential surface of the inner wall 130 and the outer circumferential surface of the stator core 120 is very narrow, a portion of the air discharged from the exhaust portion of the blades 135 impacts the outer circumferential surface of the stator core 120, and the airflow velocity along the axial direction of the outer circumferential surface of the stator core 120 is very high. As a result, the cooling performance of the motor 117 is improved.

[0313] Another portion of the air discharged from the exhaust portion of the blade 135 is discharged to the outside of the motor housing 109 via the outside of the motor 117, or moves toward the PCB (printed circuit board) 127 through the exhaust port formed between the bridge portions 147 of the second housing to cool the PCB 127, IGBT 128, capacitor 129, etc., and is discharged to the outside of the second housing.

[0314] In addition, the air outside the outer wall portion 133 of the motor housing 109 can impact the outer peripheral surface of the stator core 120 together with the main flow due to the high flow velocity of the air passing through the exhaust portion of the blade 135.

[0315] Backflow refers to the flow in which a portion of the air discharged to the outside of the second housing flows back into the interior of the motor housing 109, i.e., the air cavity 150, via the internal flow path of the motor 117, and is then discharged via the discharge flow path 144. The discharge flow path 144 is the flow path between the outer peripheral surface of the stator core 120 and the inner peripheral surface of the inner wall portion 130.

[0316] Observing the path of the reflux flow, when a portion of the air discharged from the exhaust portion of blade 135 impacts the outer peripheral surface of the stator core 120, the air velocity is significantly faster than the air velocity in the air cavity 150. Therefore, the pressure in the discharge path 144 is significantly lower than the pressure in the air cavity 150.

[0317] Therefore, under the pressure difference between the exhaust flow path 144 and the air cavity 150, the air in the air cavity 150, together with a portion of the air discharged from the exhaust portion of the blade 135, travels straight along the outer peripheral surface of the stator core 120 and is discharged.

[0318] According to this backflow, as a portion of the air discharged to the outside of the second enclosure is discharged through the outlet of the second enclosure, the internal flow path formed between the stator coils 123 of the motor 117, and the air cavity 150 and through the discharge flow path 144, the heated air inside the motor 117 is replaced by the cold air outside, thereby improving the cooling performance of the motor 117.

[0319] Furthermore, the air outside the outer wall portion 133 can move towards the outer peripheral surface of the stator core 120 due to the high air velocity passing through the blades 135. This can be named the third flow ③. As a result, the air outside the outer wall portion 133 cools the outer peripheral surface of the stator core 120, thereby improving the cooling performance of the motor 117.

[0320] Figure 10 It is a graph showing the temperature change of motor 117 based on the placement length (or phase difference) of stator core 120.

[0321] Figure 11 It shows based on Figure 10 A conceptual diagram showing the configuration relationship between the motor housing 109 and the stator 119 in terms of phase difference. Figure 11 (a) shows the configuration of the motor housing 109 and the stator 119 when the phase difference ΔD is greater than 0. Figure 11 (b) shows the configuration of the motor housing 109 and the stator 119 when the phase difference (Δd) is 0.

[0322] Reference Figure 10 When the installation length of stator core 120 is relatively short ( Figure 3 (a) and Figure 4 (a) of the optimal length ( Figure 3 (b) and Figure 4 The comparison is made when the phase difference (ΔD, Δd = the ejection end of blade 135 - the upstream end 1201 of stator core 120) is 6mm, 3mm, and 0mm.

[0323] An example of a shorter stator core 120 installation length is when the phase difference ΔD is 6mm or 3mm. An example of an optimal stator core 120 installation length is when the phase difference Δd is 0mm.

[0324] With a phase difference ΔD of 6 mm, the temperature of motor 117 is 0°C. With a phase difference ΔD of 3 mm, the temperature of motor 117 is a value greater than 0 and less than 1, approximately 0.8°C. With a phase difference Δd of 0 mm, the temperature of motor 117 is -7.6°C. The reason for not specifying the temperature unit here is that the temperature value is not limited to this, but rather represents a relative value that changes with the phase difference ΔD.

[0325] Therefore, it can be confirmed that the temperature of motor 117 is at its lowest when the phase difference Δd is 0 mm.

[0326] Reference Figure 11 The phase differences ΔD and Δd are L1-L2. L1 can refer to the axial length of the blade 135 (including the first blade 1352 and the second blade 1353) with the inner side of the motor housing 109 as a reference. Alternatively, L1 can refer to the axial length of the inner wall portion 130 with the inner side of the motor housing 109 as a reference.

[0327] L2 is the installation length of the stator core 120. The installation length L2 of the motor 117 refers to the axial distance between the upstream end 1201 of the stator core 120, with the inner side of the motor housing 109 as the reference.

[0328] exist Figure 11 In comparative example (a), when the stator core 120 has a shorter installation length, for example, when the phase difference ΔD is 6 mm or 3 mm, the above-mentioned... Figure 10 The medium temperature is 0 or 0.8, while the temperature of motor 17 is relatively high.

[0329] exist Figure 11 (b) When the stator core 120 of this embodiment is placed at its optimal length, for example when the phase difference Δd is 0 mm, in the above-mentioned Figure 10 The medium temperature is -7.6°C, and the temperature of motor 117 is relatively low.

[0330] Figure 12 It is a graph used to compare the saturation time and saturation temperature of the existing structure with the structure of this utility model that uses the air cavity 150.

[0331] Table 1 is a conceptual diagram showing the temperature of the stator 119, magnets, bearings, etc., based on the placement length of the iron core.

[0332] [Table 1]

[0333]

[0334] When the air cavity 150 is applied inside the motor housing 109 in this embodiment, the time required to reach the saturation temperature (saturation time 2) that can absorb the heat of the motor 117 is delayed compared to the time required to reach the saturation temperature (saturation time 1) when the air cavity 150 is not applied inside the motor housing 109 in the comparative example.

[0335] Table 1 shows the results of measuring the temperature (°C) of the upstream end of the stator coil 123, etc., based on the phase difference ΔD and the placement length of the stator core 120. In Table 1, coil refers to stator coil 123, core refers to stator core 120, magnet refers to permanent magnet, bearing refers to first bearing 107, and bearing refers to second bearing 108.

[0336] Referring to Table 1, the phase difference ΔD is shown as an example of 6mm, 3mm, and 0mm. The stator core 120 installation length based on the phase difference ΔD is shown as an example of 12mm, 15mm, and 18mm. The smaller the phase difference ΔD, the larger the installation length of the stator core 120.

[0337] When the phase difference ΔD decreases from 6 mm to 3 mm, the placement length of the stator core 120 increases from 12 mm to 15 mm, but the maximum temperature at the upper end of the stator coil 123 increases by 0.7 °C.

[0338] When the phase difference ΔD decreases from 6mm to 0mm, the placement length of the stator core 120 increases from 12mm to 18mm, and the maximum temperature at the upper end of the stator coil 123 decreases by 7.6℃.

[0339] When the phase difference ΔD decreases from 6 mm to 3 mm, the placement length of the stator core 120 increases from 12 mm to 15 mm, but the average temperature at the upper end of the stator coil 123 increases by 0.7 °C.

[0340] When the phase difference ΔD decreases from 6mm to 0mm, the placement length of the stator core 120 increases from 12mm to 18mm, and the average temperature at the upper end of the stator coil 123 decreases by 4.9℃.

[0341] In this embodiment, when the phase difference ΔD is 0 mm, it can be confirmed that the average temperature of the stator core 120, the average temperature of the permanent magnet, and the temperature of the first bearing 107 are all lower than the temperatures in the comparative example when the phase difference ΔD is 6 mm and 3 mm.

Claims

1. A fan motor, characterized in that, include: Protective shield; The impeller, housed within the shroud, creates an airflow. A rotating shaft, wherein the impeller is coupled to the rotating shaft; The motor housing is attached to the downstream side of the protective cover, with the airflow direction as the reference. as well as A motor, housed inside the motor housing, and including a rotor coupled to the rotating shaft and a stator surrounding the rotor, the motor driving the impeller; The motor housing includes: Outer wall portion; The inner wall portion is disposed radially inside the outer wall portion; A cover portion, based on the airflow direction, covers the upstream end of the inner wall portion; and Blades, disposed between the inner circumferential surface of the outer wall portion and the outer circumferential surface of the inner wall portion, guide the flow of air; A discharge flow path is formed between the inner wall portion and the outer peripheral surface of the stator; The air in the air cavity formed by the cover, the inner wall, and the upstream end of the motor is discharged through the discharge path due to the air flow rate through the blades.

2. The fan motor according to claim 1, characterized in that, The stator includes a stator core and stator coils wound around the stator core; The spacing of the discharge flow path is defined as the spacing between the inner circumferential surface of the inner wall portion and the outer circumferential surface of the stator core; The spacing of the discharge flow path is from above the thickness of the inner wall portion to below the radial width of the blade, and the radial width of the blade is defined as the length of the blade extending radially from the inner circumference of the outer wall portion to the outer circumference of the inner wall portion.

3. The fan motor according to claim 2, characterized in that, The spacing of the discharge flow path is 3% to 11% of the outer peripheral diameter of the outer wall or 3% to 11% of the radial outer diameter of the blade.

4. The fan motor according to claim 1, characterized in that, The height of the air cavity is defined as the interval between the inner side of the cover and the upstream end of the motor; The height of the air cavity corresponds to the length between the inner side of the cover and the downstream end of the blade.

5. The fan motor according to claim 4, characterized in that, The height of the air cavity is 22% to 42% of the radial outer diameter of the blade.

6. The fan motor according to claim 2, characterized in that, The axial distance between the inner side of the cover and the downstream end of the blade, minus the axial separation distance between the inner side of the cover and the upstream end of the stator, is defined as the phase difference; The phase difference ranges from above the protrusion height of the insulator boss to below the protrusion height of the insulator boss, which is formed by protruding from the insulator covering the upstream end of the stator core along the axial direction of the rotation axis.

7. The fan motor according to claim 1, characterized in that, The downstream end of the blade and the upstream end of the stator are arranged to overlap each other radially.

8. The fan motor according to claim 2, characterized in that, The stator core includes: A plurality of teeth protrude radially from the inside of the stator core toward the center of the rotation axis; and A plurality of slots are formed between a plurality of said teeth, and the stator coil is wound in the plurality of said slots; The air outside the motor housing forms a recirculation flow by flowing from the downstream side of the motor through the slot and moving into the air cavity.

9. The fan motor according to claim 1, characterized in that, The axial distance between the inner side of the cover and the downstream end of the outer wall is the same as the axial distance between the inner side of the cover and the downstream end of the inner wall.

10. The fan motor according to claim 1, characterized in that, The axial distance between the inner side surface of the cover and the downstream end of the inner wall is less than the axial distance between the inner side surface of the cover and the downstream end of the outer wall. The blade also includes: A blade extension, extending radially from the downstream end of the blade to cover the thickness surface of the inner wall portion; and The blade protrusion extends from the blade extension toward the discharge flow path.

11. The fan motor according to claim 1, characterized in that, The blades are composed of either a single-stage blade or an N-stage blade formed by separating themselves from each other along the direction of airflow, wherein N is a natural number greater than 2.

12. The fan motor according to claim 1, characterized in that, The motor housing includes a plurality of support portions, which protrude radially from the inner peripheral surface of the inner wall portion to surround the outer peripheral surface of the stator, and extend axially from the downstream end of the inner wall portion to support the stator. The plurality of said support portions are spaced apart in a circumferential direction along the outer peripheral surface of the stator; The discharge flow path is arranged between a plurality of adjacent support portions along the circumferential direction.

13. The fan motor according to claim 12, characterized in that, A motor mounting portion is recessed on the radial inner side of the support portion; The motor mounting portion is aligned with the motor mounting position, which is axially spaced from the inner side of the cover portion.

14. The fan motor according to claim 1, characterized in that, The motor housing includes: The first inner wall portion has a first thickness and is formed in a cylindrical shape; The second inner wall portion, with the air flow direction as a reference, is connected to the downstream side of the first inner wall portion, has a second thickness that is thicker than the first thickness, and is formed in a cylindrical shape. The inner wall of the flow path surrounds the outer peripheral surface of the first inner wall. The outer wall portion of the flow path is accommodated inside the downstream end of the protective cover and is arranged radially spaced from the outer side of the inner wall portion of the flow path; The outer wall portion is connected to the downstream end of the flow path outer wall portion and is arranged radially spaced from the outer side of the second inner wall portion; A first blade extends protruding from the outer periphery of the inner wall of the flow path towards the outer wall of the flow path; and The second blade is connected in communication with the downstream end of the first blade and extends protruding from the outer periphery of the second inner wall portion toward the outer wall portion.

15. The fan motor according to claim 1, characterized in that, The outer wall portion is attached to the downstream end of the protective cover.

16. The fan motor according to claim 1, characterized in that, The motor housing includes: A first bearing, positioned downstream of the impeller and supporting the upstream side of the rotating shaft, is arranged with reference to the airflow direction; and A first bearing housing is disposed in the center of the cover portion to house the first bearing.

17. The fan motor according to claim 16, characterized in that, A support portion is formed by protruding from the inner peripheral surface of the inner wall portion toward the rotation axis to support the outer peripheral surface of the stator; The second bearing is disposed on the downstream side of the motor with reference to the airflow direction, and supports the downstream side of the rotating shaft. The second bearing housing accommodates the second bearing; The connecting portion is connected to the downstream end of the support portion; and The bridge portion extends radially to connect with the outer peripheral surface of the second bearing housing and the inner peripheral surface of the joint portion.

18. The fan motor according to claim 1, characterized in that, The device includes a control unit disposed downstream of the motor. The control unit includes a PCB on which IGBTs and capacitors are mounted. The control unit controls the operation of the motor. The leads electrically connected to the stator are connected to the power supply connection portion provided on the PCB.

19. The fan motor according to claim 18, characterized in that, The PCB is configured to face the air cavity axially. Air discharged from the air cavity via the exhaust path moves toward the PCB to cool the IGBT and the capacitor.

20. The fan motor according to claim 18, characterized in that, Air flows between the downstream side of the motor and the PCB through an internal flow path formed inside the motor to move into the air cavity, thereby forming a recirculation flow.

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