Fan motor

Abstract

The invention relates to a fan motor. The fan motor includes a motor housing that guides a flow of air generated by the impeller. The motor cover body comprises an outer wall part and an inner wall part which is separated from the inner side of the outer wall part. The motor cover includes blades extending between the outer wall portion and the inner wall portion to guide a flow of the air. The motor cover body further comprises a blade extending part which extends from the downstream side end part of the blade and covers at least one part of the thickness surface of the inner wall part. As a result, the blade extension portion can minimize flow loss due to vortex generation when a part of the air passing through the flow path portion moves toward the motor accommodating portion, and can improve cooling performance of the motor.

Description

Technical Field

[0001] The present invention relates to a fan motor, and more particularly, to a fan motor capable of reducing flow loss and improving cooling performance of the motor. Background Art

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

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

[0004] For example, the motor may be fastened to a fan (FAN). The fan may receive power from the motor to rotate at a high speed, thereby generating an air flow.

[0005] The handheld vacuum cleaner or hair dryer works when it is directly held by the user.

[0006] In order to improve portability and convenience for users, it is necessary to achieve miniaturization and weight reduction of vacuum cleaners, hair dryers, etc.

[0007] In order to reduce the weight of the vacuum cleaner fan motor, plastic material can be used as the material of the cover instead of metal material.

[0008] Patent document CN113530868A (hereinafter referred to as Patent Document 1), which is related to the blade structure of a fan motor, discloses a fan motor. According to Patent Document 1, a fixed impeller includes a hub, a support portion, a plurality of blades, and a deflector. The plurality of blades are provided on the outer circumference of the support portion. The plurality of blades are spaced apart and arranged circumferentially around the outer end of the hub. One end of the deflector is connected to the support portion, and the other end of the deflector extends toward the central axis of the hub.

[0009] In such a configuration, air can flow into the motor side through the hole formed in the support portion and then be guided by a deflector.

[0010] However, when Patent Document 1 is applied to a small fan motor, there is a problem that there is no extra space inside the motor cover, and thus the deflector cannot be provided.

[0011] In addition, in Patent Document 1, due to the air flow path structure formed by the blades extending along the outer peripheral surface of the support portion and the deflector extending in an arc shape from the inner peripheral surface of the support portion toward the central axis of the hub, the flow paths are separated from each other, causing the air to disperse, resulting in a sudden change in the flow path, thereby posing a problem of increased flow losses.

[0012] Patent document KR10-2023-0072178A (hereinafter referred to as Patent Document 2), which is related to a fan motor blade structure, discloses a fan motor assembly. According to Patent Document 2, a portion of the inner wall connected to the inner end of the guide blade is removed, thereby forming an opening through the portion of the inner wall in a radial direction toward the motor.

[0013] The air can move in the axial direction along the guide blades and then move toward the motor through the opening to cool the motor.

[0014] However, the guide vanes in Patent Document 2 do not take into account the thickness formed between the outer peripheral surface and the inner peripheral surface of the inner wall, and are not formed on the thickness surface. Therefore, there is a problem that when the air moves toward the motor through the opening, the vortex of the air generated on the thickness surface causes a large flow loss. Summary of the Invention

[0015] Problems to be solved by the invention

[0016] An object of the present invention is to provide a fan motor having a structure that can solve the above-mentioned problems.

[0017] The first object is to provide a fan motor having a structure capable of minimizing flow loss and improving the cooling performance of the motor.

[0018] A second object is to provide a fan motor having a structure in which the blade structure is simple and the flow path efficiency can be improved.

[0019] A third object is to provide a fan motor that can improve the cooling effect of the motor without reducing the flow path efficiency.

[0020] Technical solutions to the problem

[0021] As a result of in-depth research by the inventors, it was found that the problem of the present invention and the first to third purposes mentioned above can be achieved through the following embodiments of the present invention.

[0022] In order to achieve the first objective described above, the fan motor of the present invention includes: a shroud; an impeller rotatably mounted inside the shroud about a rotation axis; a motor including a rotor connected to the rotation axis and a stator surrounding the rotor; and a motor cover body coupled to the downstream end of the shroud with respect to the flow direction of air drawn into the shroud by the impeller. The motor cover body includes an outer wall portion, an inner wall portion, blades, and a blade extension portion. The outer wall portion, together with the shroud, forms the appearance of the fan motor. The outer wall portion is coupled to the shroud. The inner wall portion is arranged on the inner side of the outer wall portion toward the rotation axis. The inner wall portion accommodates the motor. The blades are formed to protrude from the inner circumferential surface of the outer wall portion toward the outer circumferential surface of the inner wall portion. The blade extension portion extends from the downstream end of the blade toward the rotation axis with respect to the flow direction of the air. The blade extension portion covers at least a portion of the thickness surface between the outer circumferential surface and the inner circumferential surface of the inner wall portion. Thus, the blade extension can minimize air flow loss when part of the air passing through the blade moves toward the inner side of the inner wall portion. The air flowing into the inner side of the inner wall portion can improve the cooling performance of the motor by exchanging heat with the motor.

[0023] To achieve the second objective, the blade extension can extend to the inner circumference of the inner wall. Thus, the blade extension has a simple structure and can improve flow efficiency. The blade extension can minimize the generation of vortices at the downstream end of the inner wall.

[0024] To achieve the third objective, the motor cover may further include a blade protrusion extending from the blade extension portion so as to radially protrude from the inner circumferential surface of the inner wall portion toward the rotating shaft. The blade protrusion can thereby more smoothly guide air flow from the downstream end of the blade or the inner wall portion toward the motor, thereby improving motor cooling without reducing airflow efficiency.

[0025] The protruding length of the blade protrusion may be greater than 1 time and less than 2 times the thickness of the inner wall portion. Thus, the blade protrusion can minimize the generation of eddy currents on the inner wall portion.

[0026] Both the inner wall portion and the outer wall portion may be cylindrical. The inner wall portion, extending axially relative to the position where the blades begin to form, may be shorter than the outer wall portion. Thus, by forming a radial opening at the downstream end of the inner wall portion, the air flow can be directed toward the motor.

[0027] The motor housing may include a support portion that protrudes from the inner circumferential surface of the inner wall portion and supports the outer circumferential surface of the stator. An opening may be formed radially through the downstream end of the inner wall portion toward the outer circumferential surface of the stator, based on the air flow direction. The blade extensions thereby guide the air flow direction, causing air passing through the blades to flow toward the motor via the opening.

[0028] The opening portion extends circumferentially along the periphery of the inner wall portion. The opening portion may include a plurality of inlet openings divided by the blade extension portion in the circumferential direction. Thus, the blade extension portion can evenly distribute the amount of air flowing into the inner side of the inner wall portion through the plurality of inlet openings.

[0029] The blades extend along the outer circumferential surface of the inner wall portion at an angle relative to the axial direction and are formed into a curved surface shape. The blades may be provided in plurality and spaced apart in the circumferential direction along the outer circumferential surface of the inner wall portion. Thus, the plurality of blades can smoothly guide the flow of air.

[0030] The blade extensions and blade protrusions may be provided in plurality and arranged circumferentially spaced apart along the inner circumferential surface of the inner wall portion, thereby evenly distributing the amount of air flowing toward the motor.

[0031] The blades can be composed of a single-stage blade or N-stage blades (N is a natural number greater than 2) separated from each other in the axial direction. Thus, the single-stage blades can minimize the reduction in flow path efficiency. The two-stage blades have the advantage of being easy to manufacture.

[0032] The motor cover may further include a cover extension portion extending axially from a downstream end portion of the outer wall portion with respect to the air flow direction, thereby improving the cooling effect of the motor without reducing the flow path efficiency.

[0033] The ratio of the radial width of the blade to the diameter of the outer wall portion may be 3% to 11%. Thus, the blade can minimize the reduction in flow path efficiency and achieve miniaturization of the fan motor.

[0034] The ratio of the axial length of the blade to the diameter of the outer wall portion may be 25% to 50%. Thus, the diameter of the outer wall portion can be minimized and the volume of the inner wall portion for accommodating cooling air can be increased.

[0035] The motor housing may further include: a first bearing disposed downstream of the impeller relative to the air flow direction and supporting the upstream side of the rotating shaft; a first bearing housing housing the first bearing; and a connecting portion extending radially from an outer peripheral surface of the first bearing housing toward an upstream end of the inner wall. The first bearing housing and the connecting portion, together with the inner wall, may form a space for accommodating the motor.

[0036] The stator can be axially spaced apart from the inner side surface of the connecting portion. The stator includes: a stator core; and a stator coil wound around the stator core. Based on the air flow direction, the upstream end of the stator coil can be radially overlapped with the blade extension. Thus, the blade extension can direct the air flow toward the stator coil.

[0037] Based on the air flow direction, the upstream end of the stator core can be arranged to correspond to the downstream end of the outer wall. Thus, air flowing through the flow path between the inner wall and the outer wall, and air flowing from outside the outer wall through the opening in the outer wall, can cool the stator core, thereby improving the cooling performance of the motor.

[0038] The motor cover may include at least one of a first inner wall portion, a second inner wall portion, a flow path inner wall portion, a flow path outer wall portion, an outer wall portion, a first blade, and a second blade. The first inner wall portion has a first thickness and is cylindrical. The second inner wall portion is connected to the downstream side of the first inner wall portion with respect to the air flow direction, has a second thickness thicker than the first thickness, and is cylindrical. The flow path inner wall portion surrounds the outer circumferential surface of the first inner wall portion. The flow path outer wall portion is housed inside the downstream end of the shroud and radially spaced from the flow path inner wall portion on the outside of the flow path inner wall portion. The outer wall portion is connected to the downstream end of the flow path outer wall portion and radially spaced from the second inner wall portion on the outside of the second inner wall portion. The first blade protrudes from the outer circumferential surface of the flow path inner wall portion toward the flow path outer wall portion. The second blade may be communicatively connected to the downstream end of the first blade and protrude from the outer circumferential surface of the second inner wall portion toward the outer wall portion. Thus, the first blade and the second blade can constitute a second-stage blade. The flow path inner wall portion and the flow path outer wall portion can form an upstream flow path of the second-stage blade. The second inner wall portion and the outer wall portion can form a downstream flow path of the second-stage blade.

[0039] The outer wall portion may be coupled to a downstream end portion of the shroud, thereby allowing the motor cover and the shroud to be securely fastened to each other.

[0040] The motor housing may include a support portion that protrudes radially inward from the inner circumferential surface of the inner wall portion and supports the stator. Thus, the support portion supports the outer circumferential surface of the stator while forming a space between the outer circumferential surface of the stator and the inner wall portion, so that air can flow through the space.

[0041] The motor housing may further include a motor placement portion, which is recessed on one side of the support portion to surround the outer circumference of the stator. Thus, the motor placement portion and the support portion form a step in the radial direction, thereby limiting the axial movement of the stator.

[0042] The fan motor may include at least one of a support portion, a second bearing, a coupling portion, and a bridge portion. The support portion may be formed to protrude from the inner circumferential surface of the inner wall portion toward the rotating shaft to support the outer circumferential surface of the stator. The second bearing may be arranged on the downstream side of the motor based on the flow direction of the air, and support the downstream side of the rotating shaft. The second bearing cover may accommodate the second bearing. The coupling portion may be coupled to the downstream side end portion of the support portion. The bridge portion may extend radially to connect to the outer circumferential surface of the second bearing cover and the inner circumferential surface of the coupling portion. Thus, the coupling portion and the bridge portion may firmly fasten the support portion and the second bearing cover of the motor cover.

[0043] Effects of the Invention

[0044] According to the embodiments of the present invention, the following effects can be achieved.

[0045] First, the motor cover is positioned downstream of the impeller, based on the flow direction of air passing through the impeller. The motor cover includes an inner wall portion, an outer wall portion, and a plurality of blades. The inner wall portion forms the inner wall of the flow path portion. The inner wall portion forms a motor housing portion that accommodates the motor. The outer wall portion is spaced apart from the inner wall portion toward the outside of the flow path portion. The outer wall portion forms the outer wall of the flow path portion. A plurality of blades are radially projecting between the outer circumferential surface of the inner wall portion and the inner circumferential surface of the outer wall portion. The blades extend along the outer circumferential surface of the inner wall portion at an angle relative to the axial direction. The blades are formed into a curved shape. The blades guide the flow of air passing through the impeller. The motor cover includes a blade extension portion. The blade extension portion extends radially inward from the downstream end of the blade to cover at least a portion of the thickness of the inner wall portion. The blade extension portion can extend to the inner circumferential surface of the inner wall portion. As a result, a portion of the air passing through the flow path portion can be guided by the blade extension portion. The blade extension portion can minimize flow losses of air moving toward the motor housing portion.

[0046] Second, the motor cover may further include a blade protrusion that extends radially inward from the blade extension portion to protrude from the inner circumference of the inner wall portion. The blade extension and the blade protrusion can improve the flow efficiency of the air guided by the blades and enhance the cooling performance of the motor.

[0047] Third, a plurality of support portions are provided on the inner wall portion. The support portions protrude radially from the inner circumferential surface of the inner wall portion. The support portions extend axially along the inner circumferential surface of the inner wall portion. The plurality of support portions are spaced circumferentially along the inner circumferential surface of the inner wall portion. The support portions surround the outer circumferential surface of the motor stator. Thus, the support portions support the stator.

[0048] Fourth, the support portion separates the inner circumference of the inner wall portion from the outer circumference of the stator, thereby forming a radial gap between the inner wall portion and the stator. Part of the air passing through the blades can move toward the motor housing portion through the radial gap.

[0049] Fifth, an opening may be formed radially through one side of the inner wall. The opening extends circumferentially along the periphery of the inner wall. The opening may include a plurality of inlet openings divided by blade extensions or blade protrusions at equal intervals along the circumference. The plurality of blade extensions and blade protrusions can utilize the openings to direct the axial flow of air into a radial direction. Furthermore, the plurality of blade extensions and blade protrusions can evenly distribute the flow of air moving through the plurality of inlet openings toward the motor housing. BRIEF DESCRIPTION OF THE DRAWINGS

[0050] Figure 1 This is a perspective view showing the appearance of a fan motor according to an embodiment of the present invention.

[0051] Figure 2 yes Figure 1 Exploded view of the fan motor in the .

[0052] Figure 3 Is used to illustrate Figure 1 A cross-sectional view of the internal structure of the fan motor.

[0053] Figure 4 It is shown in Figure 1 Concept art of the scene with the shield removed.

[0054] Figure 5 Is used to illustrate Figure 1 Conceptual diagram of the structure of the second-stage blade.

[0055] Figure 6 It is enlarged to show Figure 3 A conceptual diagram of the structure of the flow path section in FIG.

[0056] Figure 7 It is shown in Figure 3A conceptual diagram of a situation in which a blade extension portion and a blade protrusion portion are provided at an outlet end of a blade of a motor cover according to an embodiment of the present invention.

[0057] Figure 8 It is shown in Figure 3 A conceptual diagram of a motor cover according to an embodiment of the present invention, in which a blade protrusion radially extends from a blade. Figure 8 (a) is a cross-sectional view showing a radial cross section of the motor cover. Figure 8 (b) is a conceptual diagram showing a state where the motor cover is viewed in the axial direction.

[0058] Figure 9 This is a conceptual diagram showing a state in which a blade extension portion extends radially from a blade in a motor cover according to another embodiment of the present invention. Figure 9 (a) is a cross-sectional view showing a radial cross section of the motor cover. Figure 9 (b) is a conceptual diagram showing a state where the motor cover is viewed in the axial direction.

[0059] Figure 10 This is a conceptual diagram for comparing and explaining the lengths of the inner wall portion, the blade extension portion, and the blade protrusion portion extending from the blade of the motor cover of the present invention.

[0060] Figure 11 This is a conceptual diagram showing a structure in which the width of the flow path portion is increased and the cover extension portion extends axially from the motor cover in a second-stage blade according to still another embodiment of the present invention.

[0061] Figure 12 This is a conceptual diagram showing a first-stage blade structure according to yet another embodiment of the present invention. DETAILED DESCRIPTION

[0062] Hereinafter, a fan motor according to an embodiment of the present invention will be described in detail with reference to the accompanying drawings.

[0063] In the following description, in order to make the features of the present invention clearer, the description of some components may be omitted.

[0064] 1. Definition of terms

[0065] Terms including ordinal numbers such as "first" and "second" may be used to describe various components, but the components are not limited by these terms. These terms are used only to distinguish one component from other components.

[0066] When a component is referred to as being “connected” or “linked” to another component, it should be understood that it may be directly connected or linked to the other component, but other components may also be present between them. Conversely, if a component is referred to as being “directly connected” or “directly linked” to another component, it should be understood that no other components exist between them.

[0067] Unless the context clearly indicates otherwise, expressions in the singular used in this specification include expressions in the plural.

[0068] The term "fan motor" used in the following description should be understood as a concept of a device that rotates a fan using power of an electric motor or the like to suck in or blow air.

[0069] The term "radial" or "radial shape" used in the following description refers to a shape extending from a center point to all sides like wheel spokes.

[0070] The term "thrust" used in the following description refers to the force applied to the impeller or the rotating shaft to which the impeller is mounted when the impeller draws in a fluid such as air in the axial direction and the fluid applies the same force to the impeller in the direction opposite to the axial direction.

[0071] The "axial direction" used in the following description refers to the longitudinal direction of the rotation shaft.

[0072] The "radial direction" used in the following description refers to the length direction of a line segment from the center of a circle or a cylinder to a point on the circumference (circumference).

[0073] The "circumferential direction" used in the following description refers to the direction of the circumferential edge.

[0074] 2. Description of the structure of the fan motor according to one embodiment of the present invention

[0075] Figure 1 This is a perspective view showing the appearance of a fan motor according to an embodiment of the present invention.

[0076] Figure 2 yes Figure 1 Exploded view of the fan motor in the .

[0077] Figure 3 Is used to illustrate Figure 1 A cross-sectional view of the internal structure of the fan motor.

[0078] Figure 4 It is shown in Figure 1 A conceptual diagram showing a case where the shield 100 is removed.

[0079] Figure 5 Is used to illustrate Figure 1 A conceptual diagram of the structure of the second-stage blade 123.

[0080] Figure 6 It is enlarged to show Figure 3 A conceptual diagram of the structure of the flow path portion 115 in FIG.

[0081] Figure 7 It is shown in Figure 3 A conceptual diagram of a situation in which a blade extension portion and a blade protrusion portion are provided at an outlet end of a blade of a motor cover according to an embodiment of the present invention.

[0082] Figure 8 It is shown in Figure 3 FIG. 1 is a conceptual diagram showing a motor housing 110 according to an embodiment of the present invention, in which the blade protrusion 125 radially extends from the blade 123 . Figure 8 (a) is a cross-sectional view showing a radial cross section of the motor housing 110 . Figure 8 (b) is a conceptual diagram showing a state where the motor housing 110 is viewed in the axial direction.

[0083] The fan motor of the present invention can be applied to household appliances such as handheld vacuum cleaners.

[0084] The fan motor may be mainly composed of a housing, an impeller 130 and a motor 133 .

[0085] The housing forms the appearance of the fan motor. The housing includes a shroud 100 and a first housing 110. Here, the first housing accommodates the motor inside and is therefore named a motor housing 110. The housing can be formed of a plastic material.

[0086] The shroud 100 is provided with a housing space for housing the impeller 130 therein. The housing space of the shroud 100 may house a portion of the blades 123 described later, a portion of the motor housing 110, or the first bearing 112.

[0087] A movement path of the air generated by the impeller 130 may be formed in a space between the shroud 100 and the impeller 130 , a flow path portion 115 to be described later, and the like.

[0088] The shield 100 may be formed in a cylindrical shape. It should be noted that the diameter of the shield 100 may be formed differently along the length direction of the cylinder.

[0089] The detailed structure of the shroud 100 includes an inlet 101, an inclined portion 102, and a straight portion 104. The detailed components of the shroud 100 can be divided in order from upstream to downstream of the shroud 100 based on the air flow direction.

[0090] The suction port 101 is located at the upstream end of the shroud 100. The suction port 101 is formed in a cylindrical shape. Compared with other detailed structures of the shroud 100, the diameter of the suction port 101 is relatively small and the length is relatively short. The suction port 101 can be formed to penetrate in the axial direction. One end of the impeller 130 can be accommodated inside the suction port 101.

[0091] Thus, the air generated by the impeller 130 is sucked in through the suction port 101 .

[0092] The inclined portion 102 is provided on the downstream side of the suction port 101. The inclined portion 102 is formed to be inclined with respect to the rotation axis 134 so that the diameter of the inclined portion 102 gradually increases from the upstream side of the shroud 100 toward the downstream side.

[0093] The inclined portion 102 may be formed into a conical shape along the circumferential edge of the suction port 101. The inclined portion 102 may be formed into a curved surface. The inclined portion 102 may have different curvatures as it approaches the straight portion 104 described later in the axial direction from the suction port 101. One portion of the inclined portion 102 having different curvatures may have curvatures in opposite directions from another portion.

[0094] A reinforcement portion may be formed at the corner portion where the suction port 101 and the inclined portion 102 are connected. The reinforcement portion may extend in the circumferential direction. The reinforcement portion prevents the thickness of the shield 100 from being reduced at the connection portion between the suction port 101 and the inclined portion 102 and increases the thickness of the shield 100, thereby improving the strength of the shield 100.

[0095] The straight portion 104 is formed in a cylindrical shape.

[0096] The shield 100 is coupled to the motor housing 110. For example, a portion of the shield 100 may be wrapped around a portion of the motor housing 110 to be coupled thereto.

[0097] Alternatively, a portion of the shroud 100 may be brought into contact with a portion of a motor cover 110 described later and fastened with a fastening member such as a bolt.

[0098] The shield 100 may further include a first fastening portion 106 .

[0099] The first fastening portion 106 may be provided at a downstream end portion of the shroud 100. The first fastening portion 106 is coupled to a second fastening portion 126 of the motor housing 110, which will be described later.

[0100] The first fastening portion 106 extends radially outward from the downstream side of the straight portion 104. The first fastening portion 106 extends circumferentially along the downstream peripheral edge of the straight portion 104. A plurality of first fastening holes are formed axially through the first fastening portion 106. The plurality of first fastening holes are spaced apart circumferentially.

[0101] A protrusion 107 may be formed axially protruding from an outer end portion of the first fastening portion 106. The protrusion 107 may extend circumferentially along an outer peripheral edge of the first fastening portion 106. The protrusion 107 surrounds an outer peripheral surface of a second fastening portion 126 described below.

[0102] The rotating shaft 134 is provided at the center of the housing and is formed to extend in an axial direction passing through the center of the housing.

[0103] One end portion of the rotating shaft 134 is housed inside the shroud 100. The impeller 130 is rotatably mounted on one end portion of the rotating shaft 134.

[0104] The impeller 130 includes a hub 131 and a plurality of blades 132. The impeller 130 may be in the form of a diagonal flow fan.

[0105] The hub 131 is formed to be inclined in the axial direction so that the diameter of the hub 131 increases. The diameter of the hub 131 gradually increases from the upstream end to the downstream end of the hub 131 based on the air movement direction.

[0106] A shaft coupling hole is formed in the center portion of the hub 131 along the axial direction so that one end of the rotating shaft 134 can be coupled to the center portion of the hub 131 .

[0107] Each of the plurality of blades 132 may be formed to extend in a spiral shape along the axial direction of the hub 131. One end of the blade 132 may be formed to protrude radially from one axial end of the hub 131. The other end of the blade 132 may be formed to protrude axially from the other axial end of the hub 131.

[0108] The plurality of blades 132 are arranged at predetermined intervals along the circumferential direction of the hub 131 .

[0109] Thus, the impeller 130 can rotate together with the rotating shaft 134. The plurality of blades 132 rotating at high speed together with the hub 131 allows air to flow through the internal space of the shroud 100, thereby drawing in external air.

[0110] The motor housing 110 is disposed on the downstream side of the shroud 100. The motor housing 110 may include a first bearing housing 111, a connecting portion 114, a flow path portion 115, and a second fastening portion 126.

[0111] The rotating shaft 134 may be rotatably supported at both ends by a first bearing 112 and a second bearing 147. The first bearing 112 may be disposed on one side of the rotating shaft 134, and as an example, the one side may be the upstream side of the rotating shaft 134 with respect to the air flow direction. The second bearing 147 may be disposed on the other side of the rotating shaft 134, and as an example, the other side may be the downstream side of the rotating shaft 134 with respect to the air flow direction.

[0112] The first bearing 112 may be disposed adjacent to the impeller 130 on the downstream side of the hub 131 .

[0113] The first bearing 112 may be a ball bearing or an air bearing.

[0114] A rotor 135 and a stator 137 constituting a motor 133 described later may be disposed between the first bearing 112 and the second bearing 147 .

[0115] A first bearing support portion may be formed on one side of the rotating shaft 134. The first bearing 112 may be press-fitted into the first bearing support portion.

[0116] The first bearing 112 is accommodated in the first bearing housing 111. The first bearing housing 111 may be formed in a cylindrical shape. The first bearing housing 111 is formed to protrude axially from the inner end of the connecting portion 114 toward the hub 131. The first bearing housing 111 extends circumferentially to surround the outer circumferential surface of the first bearing 112.

[0117] The first stopper 113 is formed to protrude radially inward from one axial end of the first bearing housing 111. The first stopper 113 can limit the axial movement of the first bearing 112 when the first bearing housing 111 is accommodated therein.

[0118] For example, when the impeller 130 rotates, air is sucked into the inside of the shroud 100 through the suction port 101 , moves along the inner surface of the shroud 100 , and flows into the flow path portion 115 described later.

[0119] At this time, when air moves from the inlet 101 of the shroud 100 toward the first fastening portion 106 in a first axial direction, a thrust is generated in a second axial direction opposite to the first axial direction according to the law of action and reaction.

[0120] Accordingly, the first stopper 113 restricts the first bearing 112 coupled to the rotating shaft 134 from moving toward the second axial direction under the action of the thrust.

[0121] The connection portion 114 may be formed in a disc shape and radially extend from the outer peripheral surface of the first bearing housing 111 toward the upstream end of the inner wall portion 116 of the flow path portion 115 described later. The connection portion 114 may extend circumferentially along the outer peripheral edge of the first bearing housing 111.

[0122] The connection portion 114 connects the first bearing housing 111 and the flow path 115 . The radial inner side of the connection portion 114 surrounds the outer peripheral surface of the first bearing housing 111 . The radial outer side of the connection portion 114 is connected to one end of an inner wall portion 116 of the flow path 115 .

[0123] Here, the radially inner side of the connection portion 114 refers to one end portion of the connection portion 114 radially facing the rotation axis, and the radially outer side of the connection portion 114 refers to the other end portion of the connection portion 114 radially facing the direction opposite to the rotation axis.

[0124] The connection portion 114 may form one surface of a motor housing portion 108 described later. As an example of such a surface, the connection portion 114 may be an axial surface facing the rotor 135 and the stator 137 of the motor 133 in the axial direction.

[0125] The flow path portion 115 may include an inner wall portion 116 , an outer wall portion 122 , and blades 123 .

[0126] Inner wall portion 116 is formed into a cylindrical shape having a first diameter. One axial end of inner wall portion 116 is connected to the outer end of connecting portion 114. Here, the axial direction of inner wall portion 116 refers to the longitudinal direction of inner wall portion 116. Inner wall portion 116, together with connecting portion 114, can form motor housing portion 108 inside.

[0127] The outer wall portion 122 is radially spaced apart from the outer peripheral surface of the inner wall portion 116. The outer wall portion 122 is formed in a cylindrical shape having a second diameter larger than the first diameter.

[0128] The upstream end portion of the outer wall portion 122 may be received inside the downstream end portion of the shroud 100. The upstream end portion of the outer wall portion 122 and the downstream end portion of the shroud 100 are coupled to each other.

[0129] The outer wall portion 122 may further include a second fastening portion 126 .

[0130] The second fastening portion 126 may be formed to protrude radially outward from the upstream end of the outer wall portion 122. The second fastening portion 126 may extend circumferentially along the outer periphery of the outer wall portion 122. A plurality of second fastening holes are formed through the second fastening portion 126 in the axial direction.

[0131] The plurality of second fastening holes are arranged spaced apart along the circumferential direction in the second fastening portion 126. The first fastening holes and the second fastening holes are arranged to overlap in the axial direction. Fastening members such as bolts can be passed through the first fastening holes and the second fastening holes for fastening.

[0132] The outer wall portion 122 may form an outer appearance of the fan motor together with the shroud 100 .

[0133] An air flow path is formed between outer wall portion 122 and inner wall portion 116. Flow path portion 115 is disposed downstream of shroud 100. When shroud 100 and motor housing 110 are coupled together and viewed in the axial direction, the flow path formed inside flow path portion 115 is disposed inside shroud 100.

[0134] The air sucked in by the impeller 130 moves from the shroud 100 to the flow path portion 115. The flow of the air moving to the flow path portion 115 can be referred to as a main flow.

[0135] A plurality of blades 123 are provided between the inner wall portion 116 and the outer wall portion 122. The blades 123 are formed to protrude from the outer circumference of the inner wall portion 116 toward the inner circumference of the outer wall portion 122. The protruding direction of the blades 123 is inclined at a predetermined angle relative to the radial direction between the inner wall portion 116 and the outer wall portion 122.

[0136] One radial end of the blade 123 is connected to the outer peripheral surface of the inner wall portion 116 , and the other radial end of the blade 123 is connected to the inner peripheral surface of the outer wall portion 122 .

[0137] The blades 123 are formed to have a curved shape along the outer circumference of the inner wall portion 116 or the inner circumference of the outer wall portion 122, and are inclined relative to the axial direction. The curvature of the blades 123 may vary along the axial direction. For example, the curvature of the blades 123 may increase as they move from the upstream side of the flow path portion 115 to the downstream side.

[0138] Thus, the blades 123 guide the flow of air generated by the impeller 130 in one direction. For example, the plurality of blades 123 can convert the rotational flow of air rotating in the circumferential direction of the impeller 130 into an axial direction to maintain smooth air flow.

[0139] The blades 123 may be composed of a single stage of blades 123 or N stages of blades 123 (N is a natural number greater than or equal to 2).

[0140] Single-stage blades 123 are formed as one, i.e., integrally, along the outer circumference of inner wall portion 116 or the inner circumference of outer wall portion 122. N-stage blades 123 are formed as a plurality of blades 123 separated from each other in the axial direction along the outer circumference of inner wall portion 116 or the inner circumference of outer wall portion 122.

[0141] In this embodiment, a case where the blades 123 are implemented as two stages is shown.

[0142] The second-stage blade 123 may be composed of a first blade 1231 arranged on the upstream side of the flow path portion 115 and a second blade 1232 arranged on the downstream side of the flow path portion 115 .

[0143] Here, the flow path portion 115 refers to a portion where the blades 123 are formed. The axial length of the flow path portion 115 may refer to the axial length of the blades 123 .

[0144] The flow path 115 can be divided into a first flow path and a second flow path. The first flow path is located upstream of the motor housing 110 relative to the air flow direction. A first blade 1231 is provided inside the first flow path.

[0145] The second flow path portion is disposed on the downstream side of a flow path cover to be described later, with reference to the air flow direction. A second blade 1232 is provided inside the second flow path portion.

[0146] The radial widths of the flow paths of the first and second flow path portions may be formed to be constant or different from each other in the axial direction. In this embodiment, the radial width W of the flow path portion 115 is constant.

[0147] The thickness of the inner wall portion 116 may vary along the axial direction. The inner wall portion 116 may be divided into a first inner wall portion 117 and a second inner wall portion 119 based on the position of the flow path portion 115. The first inner wall portion 117 is disposed in the first flow path portion. The second inner wall portion 119 is disposed in the second flow path portion. For example, the thickness of the first inner wall portion 117 may be less than the thickness of the second inner wall portion 119.

[0148] The sum of the thicknesses of the first inner wall portion 117 and a flow path inner wall portion 128 of a flow path cover 127 described later may correspond to the thickness of the second inner wall portion 119 .

[0149] The motor housing 110 may further include a flow path housing 127 .

[0150] The flow path cover 127 is disposed in the first flow path portion and includes a flow path inner wall portion 128 , a flow path outer wall portion 129 , and first blades 1231 .

[0151] The flow path inner wall portion 128 is formed in a cylindrical shape and has an axial length corresponding to the axial length of the first inner wall portion 117 . The flow path inner wall portion 128 extends circumferentially along the outer peripheral edge of the first inner wall portion 117 .

[0152] The flow path inner wall portion 128 surrounds the outer peripheral surface of the first inner wall portion 117. The flow path inner wall portion 128 and the first inner wall portion 117 are joined to each other so that the inner peripheral surface of the flow path inner wall portion 128 and the outer peripheral surface of the first inner wall portion 117 abut against each other.

[0153] The outer peripheral surface of the flow path inner wall portion 128 and the outer peripheral surface of the second inner wall portion 119 may form the same plane along the longitudinal direction (axial direction) of the flow path inner wall portion 128 and the second inner wall portion 119. This can minimize the flow resistance of the air.

[0154] The upstream end of the flow path inner wall portion 128 is bent toward the outer periphery of the connection portion 114 to form a bent portion 1281. A recessed groove 118 is formed at the corner where the connection portion 114 and the first inner wall portion 117 meet. The recessed groove 118 is recessed radially inward from the outer periphery of the connection portion 114.

[0155] Thus, a bend 1281 is formed in the recessed groove 118. The inner circumferential surface of the flow path inner wall 128 and the outer circumferential surface of the first inner wall 117 can be tightly bonded to each other. The bend 1281 is positioned adjacent to the downstream end of the hub 131, and the hub 131 and the bend 1281 can form a streamlined curved surface. This minimizes flow resistance as air moves from the hub 131 to the bend 1281.

[0156] The flow path outer wall portion 129 is formed in a cylindrical shape and has an axial length corresponding to the axial length of the flow path inner wall portion 128. The flow path outer wall portion 129 is arranged radially outward at a predetermined distance from the outer peripheral surface of the flow path inner wall portion 128.

[0157] The flow path outer wall portion 129 extends circumferentially along the outer periphery of the first blade 1231. The thickness of the flow path outer wall portion 129 is smaller than the thickness of the straight portion 104 of the shroud 100. The thickness of the flow path outer wall portion 129 is smaller than the thickness of the outer wall portion 122.

[0158] The flow path outer wall portion 129 is coupled to the inner circumference of the straight portion 104 of the shroud 100. To this end, a coupling groove is formed radially outwardly recessed in the inner circumference of the straight portion 104. The coupling groove extends circumferentially along the inner periphery of the straight portion 104.

[0159] The flow path outer wall 129 is coupled to the coupling groove, thereby limiting the movement of the flow path outer wall 129 along the second axial direction under the thrust. The flow path cover 127 is coupled and supported between the first inner wall 117 of the motor cover 110 and the straight portion 104 of the shroud 100 .

[0160] The inner peripheral surface of the flow path outer wall portion 129 and the inner peripheral surface of the outer wall portion 122 may form the same plane along the longitudinal directions of the flow path outer wall portion 129 and the outer wall portion 122 .

[0161] A plurality of first blades 1231 are disposed between the flow path inner wall portion 128 and the flow path outer wall portion 129. The plurality of first blades 1231 are circumferentially spaced apart along the outer circumferential surface of the flow path inner wall portion 128 or the inner circumferential edge of the flow path outer wall portion 129. The inner sides of the first blades 1231 are connected to the flow path inner wall portion 128, and the outer sides of the first blades 1231 are connected to the flow path outer wall portion 129.

[0162] The first blade 1231 is formed in a curved shape along the outer peripheral surface of the flow path inner wall portion 128 or the inner peripheral surface of the flow path outer wall portion 129 and is inclined with respect to the axial direction.

[0163] The flow path inner wall portion 128 , the flow path outer wall portion 129 , and the first blades 1231 of the flow path cover 127 constitute a first flow path portion.

[0164] The second inner wall portion 119 , the outer wall portion 122 , and the second blades 1232 constitute a second flow path portion.

[0165] The outer wall portion 122 is disposed on the downstream side of the flow path outer wall portion 129. The outer wall portion 122 is disposed outside the second inner wall portion 119 at a predetermined interval.

[0166] The outer wall portion 122 may extend axially longer than the second inner wall portion 119, relative to the upstream end of the second flow path portion. Here, the upstream end of the second flow path portion refers to the portion that forms the boundary between the first and second flow paths. For example, it may refer to the portion where the first blade 1231 and the second blade 1232 are in close contact with each other.

[0167] The second fastening portion 126 is formed to protrude radially outward from the upstream end of the outer wall portion 122. The second fastening portion 126 may extend circumferentially along the outer periphery of the outer wall portion 122. The first fastening portion 106 and the second fastening portion 126 may overlap in the axial direction.

[0168] A second fastening hole is formed axially through the second fastening portion 126. A plurality of second fastening holes are provided in the second fastening portion 126. The plurality of second fastening holes are circumferentially spaced apart along the periphery of the second fastening portion 126. The second fastening holes overlap with the first fastening holes in the axial direction.

[0169] Thus, fastening members such as bolts pass through the first and second fastening holes and are coupled to the first and second fastening portions 106 and 126. The second fastening portion 126 is coupled to the downstream side of the first fastening portion 106. The shroud 100 and the motor housing 110 may be fastened together using a plurality of fastening members.

[0170] A plurality of second blades 1232 are disposed between the second inner wall portion 119 and the outer wall portion 122. The number of first blades 1231 and the number of second blades 1232 may be different. The inner side of the second blade 1232 is connected to the second inner wall portion 119, and the outer side of the second blade 1232 is connected to the outer wall portion 122.

[0171] The first flow path portion and the second flow path portion are coupled to communicate with each other in the axial direction.

[0172] The downstream end of the first blade 1231 and the upstream end of the second blade 1232 may be spaced apart from each other by a gap, so that the air moving along the first blade 1231 and the air moving along the second blade 1232 can flow continuously and smoothly without interruption.

[0173] The motor housing portion 108 is provided inside the flow path portion 115 . The motor 133 is housed in the motor housing portion 108 .

[0174] In order to support the motor 133, a support portion 141 is provided in the motor housing 108. The support portion 141 is formed to protrude radially inward from the inner circumferential surface of the inner wall portion 116. The support portion 141 extends axially along the inner circumferential surface of the inner wall portion 116.

[0175] Support portion 141 may extend axially along the inner circumference of first inner wall portion 117. The support portion surrounds the outer circumference of stator core 138, described later. Blocks 142 are formed at the corners where support portion 141 and connecting portion 114 meet. Blocks 142 may have a trapezoidal cross-section based on a radial cross-section. Blocks 142 may extend circumferentially along the periphery of connecting portion 114.

[0176] The first surface of the end surface of block 142 is in contact with connection portion 114. The second surface, which is another surface of the end surface of block 142, is in contact with the inner circumferential surface of inner wall portion 116. The third surface of the end surface of block 142, which connects the first surface and support portion 141, can be formed at an angle. The fourth surface of the end surface of block 142, which connects the second surface and the third surface, can be integrally connected to one end of support portion 141.

[0177] The axial length of the support portion 141 is greater than the axial length of the stator core 138 .

[0178] A plurality of support portions 141 are provided on the inner circumference of the inner wall portion 116. The plurality of support portions 141 are spaced apart circumferentially along the inner circumference of the inner wall portion 116. In this embodiment, three support portions 141 are provided, and the plurality of support portions 141 may be spaced apart at intervals of 120 degrees.

[0179] The motor 133 may include a rotating shaft 134 , a rotor 135 , and a stator 137 .

[0180] The rotating shaft 134 is disposed at the center of each of the shroud 100, the motor housing 110, and the second housing 146. The rotating shaft 134 extends along a center line passing through the centers of the shroud 100, the motor housing 110, and the second housing 146.

[0181] A first bearing support portion to which the first bearing 112 is coupled is formed on one side of the rotating shaft 134 , and a second bearing support portion to which the second bearing 147 is coupled is formed on the other side of the rotating shaft 134 .

[0182] The rotor 135 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 135 includes permanent magnets 136. The rotor 135 may also optionally include a rotor core.

[0183] The permanent magnet 136 may be coupled to the rotating shaft 134 or to the rotor core. In this embodiment, the rotor core is omitted to achieve miniaturization of the motor and the permanent magnet 136 is coupled to the rotor support portion of the rotating shaft 134.

[0184] The stator 137 surrounds the rotor 135, such as the permanent magnet 136. The stator 137 and the permanent magnet 136 may be separated by a predetermined air gap.

[0185] The stator 137 includes a stator core 138 and a stator coil 139. The stator core 138 includes a back yoke, a plurality of teeth, and a plurality of slots. The back yoke may be formed in a cylindrical shape.

[0186] The teeth may be formed to protrude radially inward from the inner circumferential surface of the back yoke toward the rotating shaft 134. A plurality of teeth may be arranged circumferentially spaced apart along the circumferential edge of the inner circumferential surface of the back yoke. A groove may be formed between two adjacent teeth in the circumferential direction.

[0187] The slots are formed to penetrate the stator core 138 in the axial direction. The plurality of teeth and the plurality of slots are alternately arranged in the circumferential direction.

[0188] The stator coil 139 may be composed of a plurality of three-phase coils. The stator coil 139 is wound around the teeth. An insulator 140 is provided between the stator coil 139 and the stator core 138 to achieve electrical insulation.

[0189] The slots formed between the teeth wound with the stator coil 139 may form an internal flow path for cooling the motor. Air may flow through the internal flow path to cool the motor 133.

[0190] A lead wire 154 for applying power extends axially from one side of the stator coil 139. The lead wire 154 can receive external power through a power connection portion 155 described later.

[0191] With this configuration, when a power source such as an alternating current is applied to stator coil 139, a magnetic field is generated around stator coil 139. Due to the electromagnetic interaction between rotor 135 and stator 137, rotor 135 rotates relative to stator 137. Permanent magnet 136 rotates together with rotating shaft 134, generating a rotational force.

[0192] The impeller 130 coupled to one side of the rotation shaft 134 rotates by the rotational force transmitted via the rotation shaft 134 .

[0193] The stator core 138 is press-fitted into the plurality of support portions 141 , thereby supporting the stator 137 .

[0194] A motor placement portion 143 is provided on the inner side of the support portion 141. The motor placement portion 143 is radially recessed on the inner side of the support portion 141. The circumferential width of the support portion 141 is smaller than the spacing between the plurality of support portions 141.

[0195] The inner side surface of the motor seating portion 143 may be formed in a curved shape having a curvature corresponding to the outer peripheral surface of the stator core 138 .

[0196] Thus, the motor housing portion 143 can surround and contact the outer circumference of the stator core 138. An alignment groove 144 is formed at one axial end of the motor housing portion 143. For example, the alignment groove 144 is formed at the upstream end of the motor housing portion 143. The alignment groove 144 aligns the axial position of the stator core 138.

[0197] The alignment groove 144 is recessed radially outward from the inner side surface of the support portion 141. The alignment groove 144 forms a radial step surface at the boundary between the support portion 141 and the motor seating portion 143. The alignment groove 144 may cover a portion of one axial end of the stator core 138.

[0198] Thus, when the stator core 138 is press-fitted between the plurality of support portions 141, one axial end of the stator core 138 can be locked in the alignment groove 144. The alignment groove 144 can restrict axial movement of the stator core 138 while it is coupled to the support portion 141. Thus, the coupled position of the stator core 138 can be aligned by the alignment groove 144.

[0199] The motor seating portion 143 may further include an alignment guide 145 . The alignment guide 145 may be formed to protrude radially inward from an inner circumferential surface of the motor seating portion 143 toward the rotation shaft 134 .

[0200] The alignment guide 145 may have an arcuate cross-section. The alignment guide 145 may extend axially along the inner circumference of the motor housing 143. The circumferential width of the alignment guide 145 may be smaller than the circumferential width of the motor housing 143. An axial centerline passing through the center of the alignment guide 145 may coincide with an axial centerline passing through the center of the motor housing 143.

[0201] Thus, the alignment guide 145 can axially align the center of the stator core 138 and the center of the support portion 141 of the motor housing 110 concentrically.

[0202] The second housing 146 is disposed on the downstream side of the motor housing 110 , and includes a second bearing housing 148 , a bridge portion 152 , and a coupling portion 150 .

[0203] The second bearing cover 148 accommodates the second bearing 147. The second bearing cover 148 may be formed in a cylindrical shape and extend in the circumferential direction to surround the outer peripheral surface of the second bearing 147.

[0204] The second stopper 149 is formed to protrude radially inward from one axial end of the second bearing cover 148. Here, the axial end of the second bearing cover 148 refers to the first axial end of the second bearing cover 148 in the air flow direction.

[0205] Thus, the second stopper 149 can restrict the second bearing 147 from moving along the first axial direction when accommodated in the second bearing cover 148 .

[0206] The bridge portion may extend radially from the outer circumferential surface of the second bearing housing 148 toward the inner side surface of the coupling portion 150, described later. A plurality of bridge portions may be provided. The plurality of bridge portions may be spaced circumferentially along the outer circumferential edge of the second bearing housing 148. Thus, the bridge portion may connect the second bearing housing 148 and the coupling portion 150.

[0207] The coupling portion 150 may be coupled to the downstream end portion of the support portion 141. The coupling portion 150 may surround the downstream end portion of the support portion 141. For example, a support portion receiving groove 151 may be formed in an axial direction recessed at one axial end of the coupling portion 150.

[0208] The support portion receiving groove 151 may include a first surface, a second surface, and a third surface. The first surface of the support portion receiving groove 151 is the surface that axially faces the downstream end of the support portion 141. The second surface of the support portion receiving groove 151 may extend axially from one end of the first surface and face one of the two circumferentially opposing side surfaces of the support portion 141. The third surface of the support portion receiving groove 151 may face the other of the two circumferentially opposing side surfaces of the support portion 141.

[0209] The downstream end portion of the support portion 141 is inserted into the support portion receiving groove 151 coupled to the coupling portion 150. Alternatively, the support portion 141 and the coupling portion 150 may be fastened together using a fastening member such as a bolt.

[0210] A control unit may be disposed on the downstream side of the second housing 146. The control unit controls the overall operation of the fan motor, such as the motor 133. The control unit includes a printed circuit board 153, an IGBT (insulated gate bipolar transistor), a capacitor, and the like.

[0211] A power connection portion 155 is provided on the printed circuit board 153. The power connection portion 155 is formed to protrude from the printed circuit board 153 so as to be connectable to the lead 154. A plurality of power connection portions 155 are provided corresponding to the lead 154. The power connection portion 155 is connected to an external power source.

[0212] Thus, external power may be applied to the stator coil 139 through the power connection portion 155 and the lead wire 154 .

[0213] Next, the movement path of air will be described.

[0214] When the rotating shaft 134 of the motor 133 rotates, the air is sucked into the shroud 100 through the suction port 101 due to the rotation of the impeller 130 .

[0215] Next, the air passes through the flow path between the shroud 100 and the impeller 130 .

[0216] The air that has passed through impeller 130 then flows into blades 123 of flow path portion 115. The air then passes through first blades 1231 of the first flow path portion and second blades 1232 of the second flow path portion. The air guided by first blades 1231 can move axially along the outer circumferential surfaces of flow path inner wall portion 128 and the inner circumferential surface of flow path outer wall portion 129.

[0217] The air guided by the second blades 1232 may move in the axial direction along the outer circumferential surface of the second inner wall portion 119 and the inner circumferential surface of the outer wall portion 122 .

[0218] Part of the air passing through first blades 1231 of the first flow path portion and second blades 1232 of the second flow path portion can be discharged toward stator 137. Part of the air contacts the outer peripheral surface of stator core 138, thereby cooling the heat generated by stator core 138.

[0219] In order to cool the heat generated by the stator core 138 as quickly as possible, it is necessary to increase the contact area between the stator coil 139 and the outer peripheral surface of the stator core 138 and the air.

[0220] For example, to improve the cooling performance of the stator coil 139, it is necessary to increase the flow rate of air flowing into the motor housing 108. This is because the more air is contained in the motor housing 108, the more heat can be absorbed from the stator coil 139 exposed to the motor housing 108 in the slots of the stator core 138.

[0221] To this end, with the inner side surface of the connecting portion 114 of the motor cover 110 as a reference, the distance of the stator axially separated from the inner side surface of the connecting portion 114 can correspond to the distance of the outlet end of the inner wall portion 116 axially separated from the inner side surface of the connecting portion 114.

[0222] The upstream end of the stator coil 139 exposed from the slot to the motor housing 108 can be radially overlapped with at least one of the outlet end of the inner wall portion 116, the opening portion 120 formed at the outlet end of the inner wall portion 116, the blade extension portion 124 described later, and the blade protrusion 125.

[0223] In this embodiment, the upstream end of stator coil 139 radially overlaps with opening 120, blade extension 124, and blade protrusion 125. Thus, air guided by blade extension 124 and blade protrusion 125 is directed toward stator coil 139 through opening 120, effectively cooling stator coil 139.

[0224] In order to improve the cooling performance of the stator core 138 , preferably, the outer peripheral surface of the stator core 138 is exposed to the outside of the outer wall portion 122 as much as possible.

[0225] To this end, the distance between the inner side surface of the connecting portion 114, which forms one side of the motor housing 108, and the upstream end of the stator core 138 can be greater than or equal to the distance between the inner side surface of the connecting portion 114 and the downstream end of the outer wall portion 122. Here, the terms "upstream" and "downstream" are relative to the direction of air flow. The downstream end of the outer wall portion 122 refers to the outlet end of the outer wall portion 122 where air is discharged from the flow path portion 115.

[0226] In this embodiment, the distance between the inner side surface of the connecting portion 114 and the upstream end of the stator core 138 is the same as the distance between the inner side surface of the connecting portion 114 and the downstream end of the outer wall portion 122 .

[0227] If the axial distance between the inner side surface of the connecting portion 114 and the upstream end of the stator core 138 is smaller than the axial distance between the inner side surface of the connecting portion 114 and the downstream end of the outer wall portion 122, the outer peripheral surface of the stator core 138 is shielded by the outer wall portion 122, thereby reducing the area exposed to the outside of the outer wall portion 122 and the contact area between the stator core 138 and the air. As a result, the heat dissipation performance of the stator core 138 may be reduced.

[0228] Furthermore, if the distance between the inner side surface of the connecting portion 114 and the upstream end of the stator core 138 is significantly greater than the distance between the inner side surface of the connecting portion 114 and the downstream end of the outer wall portion 122, the length of the rotating shaft 134 becomes longer, which may cause vibration and noise in the rotating shaft 134 during high-speed rotation. In addition, the increased axial length of the fan motor may adversely affect the miniaturization of the fan motor.

[0229] The outer peripheral surface of stator core 138 and the inner peripheral surface of inner wall portion 116 have a predetermined gap in the radial direction.

[0230] If the radial distance between the outer circumference of stator core 138 and the inner circumference of inner wall 116 is too large, the air passing through blades 123 is dispersed radially, thereby reducing the amount of air that contacts the outer circumference of stator core 138. If the radial distance between the outer circumference of stator core 138 and the inner circumference of inner wall 116 is too small, the flow rate of air moving from the outlet end of inner wall 116 to stator 137 is significantly reduced or the movement of air is blocked.

[0231] Therefore, the radial distance between the outer circumference of stator core 138 and the inner circumference of inner wall 116 must be appropriately maintained. For example, the radial distance between the outer circumference of stator core 138 and the inner circumference of inner wall 116 is preferably 1T to 2T relative to the thickness T of inner wall 116.

[0232] When impeller 130 rotates at high speeds, for example, between 10,000 and 14,000 rpm, the velocity of air discharged axially from the outlet ends of blades 123 along the outer circumference of stator core 138 increases. According to Bernoulli's principle, as the air velocity increases, the pressure decreases. Consequently, the pressure on the outer circumference of stator core 138 decreases.

[0233] As a result, the air contained in motor housing 108 is sucked out of stator core 138 due to the low pressure. The air heated by heat exchange with stator coil 139, the first bearing, the rotating shaft, and the permanent magnets is discharged outside stator core 138, allowing the air to be recirculated.

[0234] That is, a portion of the air that moves toward the first axial direction along the outer peripheral surface of the stator core 138 flows back into the internal flow path of the motor 133 from the downstream end of the motor 133 and moves toward the second axial direction opposite to the first axial direction, so that it can be recirculated to the upstream end of the motor 133.

[0235] According to the air flow as described above, the air cooling the motor 133 does not stay in the motor housing 108 continuously, but circulates, so that the cooling air can be replaced by new air flowing in from the outside of the motor cover 110, thereby improving the cooling performance of the motor 133.

[0236] On the other hand, another portion of the air that has passed through the first blades 1231 of the first flow path portion and the second blades 1232 of the second flow path portion can move toward the inside of the motor housing portion 108. The air that has flowed into the inside of the motor housing portion 108 can cool the heat generated by the stator coil 139, the permanent magnet 136, the bearings, and the like.

[0237] The axial length of the second inner wall portion 119 is smaller than the axial length of the outer wall portion 122 with reference to the upstream end portion of the second flow path portion where the second blades 1232 are formed.

[0238] Thus, the outer wall portion 122 of the second flow path portion is closed radially outward, and an opening portion 120 is formed at the downstream end of the second inner wall portion 119 of the second flow path portion. The opening portion 120 is open to the inside of the motor housing portion 108. The axial height of the opening portion 120 is the difference between the axial length of the outer wall portion 122 and the axial length of the second inner wall portion 119.

[0239] Thus, a portion of the air that has passed through the second blades 1232 of the second flow path portion can move toward the inside of the motor housing portion 108 through the opening 120 of the second inner wall portion 119 .

[0240] The opening 120 is formed through the downstream end portion of the second inner wall portion 119 toward the radial inner side. The opening 120 extends in the circumferential direction along the peripheral edge of the second inner wall portion 119 .

[0241] The opening 120 may be divided into a plurality of inlets 121 by a blade extension 124 or a blade protrusion 125 described later. The plurality of inlets 121 are arranged at intervals in the circumferential direction.

[0242] Thus, the plurality of inlet ports 121 can function as a passage for the air that has passed through the flow path portion 115 to move radially inward toward the motor housing portion 108 .

[0243] Preferably, the height of the opening 120 is 10-50% of the axial length of the flow path 115. In this embodiment, the axial length of the flow path 115 may refer to the sum of the axial lengths of the flow path outer wall 129 and the outer wall 122.

[0244] If the height of opening 120 is less than 10% of the axial length of flow path 115, the flow resistance and flow loss of air moving from flow path 115 to motor housing 108 increase, thereby reducing the amount of air moving into motor housing 108. On the other hand, if the height of opening 120 is greater than 50% of the axial length of flow path 115, the flow rate of air moving into motor housing 108 increases, thereby improving the cooling performance of motor 133. However, this may reduce the suction performance of impeller 130.

[0245] In order to minimize the flow loss of air moving toward the inside of the motor housing 108, a blade extension 124 is further included that extends from the second blade 1232. The blade extension 124 is integrally formed with the second blade 1232. A plurality of blade extensions 124 are provided corresponding to the second blades 1232.

[0246] The blade extension 124 converts the flow direction of the air guided by the blade 123 from the axial direction to the radial direction. In the case of the first-stage blade, the blade extension 124 may form the blade 323 (see Figure 12 ) part. The first-stage blade refers to a blade that extends in the axial direction without separation as a single blade 323.

[0247] In the case of a two-stage blade, the blade extension 124 may form a portion of the second blade 1232. The two-stage blade refers to two blades 123 that are separated from each other in the axial direction and are continuously arranged in the axial direction.

[0248] However, if the blade 123 extends in the axial direction between the inner wall portion 116 and the outer wall portion 122 , the blade extension portion 124 extends in the radial direction at the downstream side end portion of the blade 123 .

[0249] The blade extension 124 covers the downstream end of the second inner wall portion 119. The blade extension 124 may extend axially from the second blade 1232 further than the downstream end of the second inner wall portion 119. The blade extension 124 further extends radially from the downstream end of the second blade 1232 to cover at least a portion of the thickness surface of the downstream end of the second inner wall portion 119.

[0250] Here, the thickness surface of the second inner wall portion 119 is formed between the outer peripheral surface and the inner peripheral surface of the second inner wall portion 119. The downstream end portion of the second inner wall portion 119 refers to the axial end portion of the second inner wall portion 119 based on the flow direction of air flowing in the axial direction along the outer peripheral surface of the second inner wall portion 119.

[0251] In this embodiment, the blade extension portion 124 covers the entire thickness of the downstream end portion of the second inner wall portion 119. That is, the blade extension portion 124 may extend to the inner circumferential surface of the inner wall portion 116.

[0252] With this configuration, the blade extension portion 124 can guide a portion of the air that has passed through the second blades 1232 toward the motor housing portion 108. An axial through hole is formed between the plurality of second blades 1232 adjacent to each other in the circumferential direction so as to penetrate in the axial direction.

[0253] Inlet openings are formed radially between circumferentially adjacent blade extensions 124. The blade extensions 124 can redirect the air passing through the second blades 1232 radially inwardly and guide it toward the inside of the motor housing 108 using the axial through-holes.

[0254] When converting the air flow from the axial direction to the radial direction, the plurality of blade extensions 124 minimize flow losses caused by vortexes in the air at the downstream end of the inner wall portion 116, thereby maintaining a continuous and smooth air flow. This increases the flow rate of air supplied to the motor housing 108, thereby improving the cooling performance of the motor 133.

[0255] In addition, the blade extension 124 can minimize the noise generated by air flow when the impeller 130 rotates at a high speed.

[0256] In addition, the blade extension portion 124 extends radially from the downstream end portion of the second blade 1232 , which has the advantages of a simple structure and improved flow path efficiency.

[0257] In order to minimize the flow loss of air moving toward the inside of the motor accommodation portion 108 , a blade protrusion 125 may be further included that protrudes from the blade extension 124 toward the inside of the second inner wall portion 119 toward the motor accommodation portion 108 .

[0258] The blade extension portion 124 and the blade protrusion portion 125 are identical or similar in that they minimize the flow loss of air moving toward the inside of the motor accommodation portion 108 .

[0259] However, since the blade protrusion 125 is formed to protrude closer to the outer peripheral surface of the stator 137 than the blade extension 124 , it is possible to obtain an effect of directly injecting the flow of air onto the outer peripheral surface of the stator 137 .

[0260] The plurality of blade extensions 124 and the plurality of blade protrusions 125 evenly divide the air moving radially inward toward the stator 137 through the plurality of inlet ports, thereby achieving an effect of evenly distributing the air in the circumferential direction along the outer periphery of the stator 137 .

[0261] The radial width W of the flow path portion 115 can have a ratio of 3 to 11% relative to the diameter D of the outer wall portion of the flow path portion 115. The radial width W of the flow path portion 115 refers to the radial width between the outer circumferential surface of the inner wall portion 116 and the inner circumferential surface of the outer wall portion 122. It can be understood that the radial width W of the flow path portion 115 is the same concept as the radial width of the blades 123.

[0262] If the radial width of blades 123 is less than 3% of the outer wall diameter D, the flow path width becomes too narrow, increasing flow resistance. If the radial width of blades 123 exceeds 11% of the outer wall diameter D, the space between the outer circumference of stator core 138 and the inner circumference of inner wall 116 becomes too narrow, reducing the flow rate of air flowing into motor housing 108 and degrading motor cooling performance.

[0263] The axial length of the flow path portion 115 may have a ratio of 25 to 50% to the diameter D of the outer wall portion of the flow path portion 115. Here, the axial length of the flow path portion 115 may refer to the sum of the axial lengths of the flow path outer wall portion 129 and the outer wall portion 122.

[0264] If the axial length of flow path 115 is less than 25% of outer wall diameter D, the distance air travels along blades 123 is shortened, increasing flow resistance. If the axial length of flow path 115 is greater than 50% of outer wall diameter D, outer wall 122 increases the flow rate of air contained within motor housing 108, thereby reducing motor cooling performance.

[0265] Figure 9 1 is a conceptual diagram illustrating a situation in which the blade extension portion 124 extends radially from the blade 123 in the motor housing 110 according to another embodiment of the present invention. Figure 9 (a) is a cross-sectional view showing a radial cross section of the motor housing 110 . Figure 9 (b) is a conceptual diagram showing a state where the motor housing 110 is viewed in the axial direction.

[0266] This embodiment is different from the above Figures 1 to 8 The embodiment of FIG. 1 is different in that the blade extension portion 124 extends from the downstream side end portion of the blade 123 to the inner peripheral surface of the inner wall portion 116, and the blade protrusion 125 is omitted.

[0267] If the blade extension portion 124 extends from the downstream end portion of the blade 123 to the inner peripheral surface of the inner wall portion 116 and the blade protrusion 125 is omitted, the manufacturing difficulty is reduced and the manufacturing cost can be saved.

[0268] Other components are the same as above Figures 1 to 9 The embodiments are the same or similar, so repeated description is omitted.

[0269] Figure 10 This is a conceptual diagram for comparing and explaining the lengths of the inner wall portion 116 , the blade extension portion 124 , and the blade protrusion portion 125 extending from the blade 123 of the motor housing 110 of the present invention.

[0270] The flow path portion 115 of the present invention includes a blade extension portion 124 extending from the second blade 1232. Alternatively, a blade protrusion portion 125 may extend radially from the blade extension portion 124 to protrude toward the inner side of the inner wall portion 116.

[0271] When the thickness of the second inner wall portion 119 is set to T mm, the radial width of the first blade 1231 or the second blade 1232 may be 1 to 3 times (1T to 3T) the thickness of the second inner wall portion 119 .

[0272] When the radial width of the second blade 1232 is 2T, the sum of the radial width of the second blade 1232 and the length of the blade extension 124 may be three times the thickness of the second inner wall portion 119 , that is, 3T.

[0273] The sum of the radial width of the second blade 1232 , the length of the blade extension portion 124 , and the length of the blade protrusion 125 may be 4 times the thickness of the second inner wall portion 119 , that is, 4T.

[0274] The radial length of the blade protrusion 125 may be 1T to 2T longer than the thickness of the inner wall portion 116 based on the inner circumferential surface of the inner wall portion 116 .

[0275] Figure 11 This is a conceptual diagram showing a structure in which the width of the flow path portion 115 increases from the upstream side to the downstream side in a second-stage blade 123 according to another embodiment of the present invention, and the cover extension portion 200 extends axially from the outer wall portion 122 of the motor cover 110.

[0276] This embodiment is different from the above Figures 1 to 10 The embodiment is different in that the radial flow path width of the flow path portion 115 increases from the upstream side to the downstream side, and the cover extension portion 200 further extends from the motor cover 110 in the axial direction.

[0277] The thickness of the flow path inner wall portion 228 of the flow path cover 227 may vary along the axial direction. The thickness of the flow path inner wall portion 228 is determined between the outer circumferential surface and the inner circumferential surface of the flow path inner wall portion 228. The inner circumferential surface of the flow path inner wall portion 228 may extend perpendicularly along the axial direction. The outer circumferential surface of the flow path inner wall portion 228 may be formed to be inclined at a predetermined angle θ relative to the axial direction.

[0278] For example, the thickness of the upstream end of the flow path inner wall portion 228 may be greater than the thickness of the downstream end of the flow path inner wall portion 228. The thickness of the flow path outer wall portion 129 is formed between the outer circumferential surface and the inner circumferential surface of the flow path outer wall portion 129. The thickness of the flow path outer wall portion 129 may be formed to be constant in the axial direction.

[0279] The radial flow path width of the first flow path portion may increase as it approaches the downstream side from the upstream side. The radial width of the blade 123 may expand as it approaches the downstream side from the upstream side of the flow path portion 115. The upstream radial width W1 of the blade 123 may be smaller than the downstream radial width W2 of the blade 123. The thickness of the second inner wall portion 219 of the second flow path portion may vary along the axial direction. The thickness of the second inner wall portion 219 is formed between the outer peripheral surface and the inner peripheral surface of the second inner wall portion 219. The inner peripheral surface of the second inner wall portion 219 may extend vertically in the axial direction. The outer peripheral surface of the second inner wall portion 219 may be formed to be inclined at a predetermined angle θ relative to the axial direction.

[0280] For example, the thickness of the upstream end of the second inner wall portion 219 may be greater than the thickness of the downstream end of the second inner wall portion 219. The thickness of the outer wall portion 122 is formed between the outer circumferential surface and the inner circumferential surface of the outer wall portion 122. The thickness of the outer wall portion 122 may be formed to be constant in the axial direction.

[0281] The inner peripheral surface of the flow path outer wall portion 129 and the inner peripheral surface of the outer wall portion 122 form the same plane in the axial direction (longitudinal direction).

[0282] The radial flow path width of the second flow path portion may increase from the upstream side to the downstream side.

[0283] With this configuration, the radial width of flow path portion 115 increases from the upstream side toward the downstream side, thereby increasing the flow rate of air moving into motor housing portion 108. This allows for stable air flow within flow path portion 115, thereby improving motor cooling performance.

[0284] A portion of the motor housing 110 may be further extended in the axial direction. The housing extension portion 200 may be further extended in the axial direction from the outer wall portion 122 of the motor housing 110 .

[0285] Thus, the cover extension 200 can achieve additional cooling effect without reducing the flow path efficiency.

[0286] The cover extension portion 200 further accommodates the air passing through the second flow path portion inside the outer wall portion 122 of the motor cover 110, thereby not only increasing the flow rate of air moving toward the inner side of the motor housing portion 108, but also increasing the flow rate of air moving toward the outer peripheral surface of the stator core 138.

[0287] In addition, the cover extension portion 200 can improve the straightness of the air passing through the second flow path portion.

[0288] The length of the cover extension portion 200 may be in the range of 25% to 55% of the axial length of the flow path portion 115. If the length of the cover extension portion 200 is less than 25% of the axial length of the flow path portion 115, the effect of improving the straightness of air passing through the flow path portion 115 may be reduced. If the length of the cover extension portion 200 is greater than 55% of the axial length of the flow path portion 115, the amount of air flowing into the motor 133 from outside may be reduced, thereby degrading the cooling performance of the motor 133.

[0289] The cover extension 200 can be independent of the above Figures 1 to 10 The blade extension 124 and the blade protrusion 125 of the embodiment are applied to a fan motor. For example, only the cover extension 200 may be applied to a fan motor, or the cover extension 200 may be applied to a fan motor together with the blade extension 124 and the blade protrusion 125.

[0290] Other components are the same as above Figures 1 to 9 The embodiments are the same or similar, so repeated description is omitted.

[0291] Figure 12 FIG. 1 is a conceptual diagram showing the structure of a first-stage blade 323 according to another embodiment of the present invention.

[0292] This embodiment is different from the above Figures 1 to 11 The embodiment is different in that the blades 323 are composed of 1-stage blades 323.

[0293] A plurality of first-stage blades 323 may be provided inside the flow path portion 315. The flow path portion 315 may include an inner wall portion 316 and an outer wall portion 322. The inner wall portion 316 may be cylindrical. The inner circumferential surface of the inner wall portion 316 may form the motor housing 108. The inner wall portion 316 may be provided in two axially separable configurations, or may be provided as a single portion.

[0294] When two inner wall portions 316 are detachably provided, a first inner wall portion may be provided on the upstream side of the flow path portion 315, and a second inner wall portion may be provided on the downstream side of the flow path portion 315. The first inner wall portion and the second inner wall portion may each be formed into a cylindrical shape. The first inner wall portion and the second inner wall portion may each extend in the axial direction and be coupled to each other.

[0295] In this embodiment, the inner wall portion 316 is formed into a cylindrical shape. In the case where the inner wall portion 316 is formed into a single shape, it can be formed into a cylindrical shape.

[0296] The outer wall portion 322 may be formed in a cylindrical shape. The outer wall portion 322 is spaced apart from the inner wall portion 316 by a predetermined distance and is arranged radially outward. Two outer wall portions 322 may be provided axially separably, or one may be provided.

[0297] In this embodiment, two detachable outer wall portions 322 are shown. The outer wall portion 322 may be composed of a first outer wall portion 3221 and a second outer wall portion 3222. The first outer wall portion 3221 may be disposed upstream of the flow path portion 315, and the second outer wall portion 3222 may be disposed downstream of the flow path portion 315.

[0298] The blades 323 may be formed in a curved shape along the outer circumference of the inner wall portion 316 and may be formed in a curved shape along the inner circumference of the first outer wall portion 3221 and the second outer wall portion 3222. The curvature and curvature direction of the blades 323 may vary along the axial direction.

[0299] Other components are the same as above Figures 1 to 11 The embodiments are the same or similar, so repeated description is omitted.

Claims

1. A fan motor, wherein: include: Shield; an impeller housed in the shroud and mounted to be rotatable about a rotation axis; a motor comprising a rotor connected to the rotating shaft and a stator surrounding the rotor; as well as a motor cover body coupled to a downstream end portion of the shroud with respect to a flow direction of air drawn into the shroud by the impeller; The motor housing comprises: an outer wall portion, forming an outer appearance of the fan motor together with the shroud, and being combined with the shroud; an inner wall portion, disposed on the inner side of the outer wall portion toward the rotating shaft, and accommodating the motor; blades protruding from the inner circumferential surface of the outer wall portion toward the outer circumferential surface of the inner wall portion; and The blade extension portion extends from a downstream end portion of the blade toward the rotation axis with respect to the air flow direction and covers at least a portion of a thickness surface between the outer peripheral surface and the inner peripheral surface of the inner wall portion.

2. The fan motor according to claim 1, wherein The blade extension portion extends to the inner circumferential surface of the inner wall portion.

3. The fan motor according to claim 1, wherein The motor cover further includes a blade protrusion portion that further extends from the blade extension portion to protrude radially from the inner circumferential surface of the inner wall portion toward the rotation shaft.

4. The fan motor according to claim 3, wherein: The protruding length of the blade protruding portion is not less than 1 times and not more than 2 times the thickness of the inner wall portion.

5. The fan motor according to claim 1, wherein The inner wall portion and the outer wall portion are both formed into a cylindrical shape; With the position where the blades begin to be formed as a reference, the length of the inner wall portion extending in the axial direction is smaller than the length of the outer wall portion. The fan motor according to claim 1 , wherein: The motor cover includes a support portion, which is formed by protruding from the inner peripheral surface of the inner wall portion and supports the outer peripheral surface of the stator; An opening is formed at a downstream end of the inner wall portion in a radial direction toward the outer peripheral surface of the stator, based on the flow direction of the air; The blade extension portion guides a flow direction of the air so that the air passing through the blade moves toward the motor via the opening portion.

7. The fan motor according to claim 6, wherein: The opening portion extends in a circumferential direction along the periphery of the inner wall portion; The opening portion includes a plurality of inflow ports divided by the blade extensions in a circumferential direction.

8. The fan motor according to claim 1, wherein The blades extend along the outer peripheral surface of the inner wall portion and are inclined relative to the axial direction and are formed into a curved surface shape; A plurality of blades are provided and are arranged spaced apart in a circumferential direction along the outer peripheral surface of the inner wall portion.

9. The fan motor according to claim 3, wherein: A plurality of the blade extension portions and a plurality of the blade protrusion portions are provided, and the plurality of the blade extension portions and the plurality of the blade protrusion portions are arranged along the inner circumferential surface of the inner wall portion and spaced apart in the circumferential direction.

10. The fan motor according to claim 1, wherein The blades are composed of single-stage blades or N-stage blades separated from each other along the axial direction, wherein N is a natural number greater than or equal to 2.

11. The fan motor according to claim 1, wherein The motor cover further includes a cover extension portion extending in an axial direction from a downstream end portion of the outer wall portion with respect to a flow direction of the air.

12. The fan motor according to claim 1, wherein The ratio of the radial width of the blade to the diameter of the outer wall portion is 3% to 11%; A ratio of the axial length of the blade to the diameter of the outer wall portion is 25% to 50%.

13. The fan motor according to claim 1, wherein The motor housing further comprises: a first bearing, disposed on the downstream side of the impeller with respect to the flow direction of the air, and supporting the upstream side of the rotating shaft; a first bearing housing for accommodating the first bearing; and The connecting portion extends radially from the outer peripheral surface of the first bearing cover toward the upstream end portion of the inner wall portion.

14. The fan motor according to claim 13, wherein The stator and the inner side surface of the connecting portion are spaced apart from each other in the axial direction; The stator comprises: stator core; and a stator coil, wound around the stator core; The upstream end portion of the stator coil and the blade extension portion are arranged to overlap in a radial direction based on the flow direction of the air.

15. The fan motor according to claim 14, wherein The upstream end portion of the stator core is arranged to correspond to the downstream end portion of the outer wall portion with respect to the flow direction of the air.

16. The fan motor according to claim 1, wherein The motor housing comprises: a first inner wall portion having a first thickness and formed in a cylindrical shape; a second inner wall portion connected to a downstream side of the first inner wall portion with respect to the air flow direction, having a second thickness thicker than the first thickness and formed in a cylindrical shape; a flow path inner wall portion surrounding an outer peripheral surface of the first inner wall portion; a flow path outer wall portion, housed inside the downstream end portion of the shroud and arranged radially spaced from the flow path inner wall portion on the outside of the flow path inner wall portion; an outer wall portion connected to a downstream end portion of the flow path outer wall portion and arranged radially spaced apart from the second inner wall portion on the outer side of the second inner wall portion; a first blade protruding and extending from the outer peripheral surface of the flow path inner wall portion toward the flow path outer wall portion; and The second blade is communicably connected to the downstream end portion of the first blade and extends protrudingly from the outer peripheral surface of the second inner wall portion toward the outer wall portion.

17. The fan motor according to claim 16, wherein The outer wall portion is coupled to a downstream end portion of the shroud.

18. The fan motor according to claim 1, wherein The motor cover includes a support portion that is formed to protrude radially inward from an inner circumferential surface of the inner wall portion and supports the stator.

19. The fan motor according to claim 18, wherein The motor cover further includes a motor placement portion, which is recessed on one side of the support portion to surround an outer circumferential surface of the stator.

20. The fan motor according to claim 13, wherein include: a support portion protruding from the inner circumferential surface of the inner wall portion toward the rotating shaft to support the outer circumferential surface of the stator; a second bearing disposed on a downstream side of the motor with respect to the flow direction of the air and supporting a downstream side of the rotating shaft; a second bearing cover, accommodating the second bearing; a coupling portion coupled to a downstream end portion of the support portion; and The bridge portion extends in a radial direction to connect the outer peripheral surface of the second bearing cover and the inner peripheral surface of the coupling portion.

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