Motor assembly

Abstract

The present application relates to a motor assembly, comprising: an impeller; a first diffuser configured at a downstream side of the impeller; a second diffuser provided at a downstream side of the first diffuser; an impeller cover combined with the second diffuser to accommodate the impeller and the first diffuser inside the impeller cover; and a motor provided at a downstream side of the second diffuser to drive the impeller to rotate; the second diffuser comprises: a hub; an outer wall concentrically configured at an outer side of the hub; and a plurality of blades connected at one side with the hub and connected at the other side with the outer wall, the impeller cover is combined with the outer wall of the second diffuser, a communication part is provided at the hub of the second diffuser, and the communication part communicates the inside and the outside of the hub of the second diffuser. Thus, the heated air can be discharged to the outside of the diffuser, so as to promote the cooling of the motor.

Description

Technical Field

[0001] This invention relates to motor assemblies. Background Technology

[0002] As we all know, a motor is a device that converts electrical energy into mechanical energy.

[0003] The motor typically includes a stator and a rotor, the rotor being rotatably configured relative to the stator with a specified air gap.

[0004] The size and weight of the motor vary depending on its intended use.

[0005] A portion of the motor is constructed from a motor assembly equipped with an impeller, which is capable of generating pressure or promoting the movement of air when rotating.

[0006] However, in such a motor assembly with an impeller, the air volume may decrease when the size of the stator and rotor is reduced.

[0007] In such a motor assembly with an impeller, when the size of the stator and rotor is reduced, the rotor speed can be increased to maintain the same airflow.

[0008] However, in such a motor assembly with an impeller, there is a problem of excessive temperature rise in the stator and rotor when the speed of the impeller and rotor is increased.

[0009] In addition, when the speed of the impeller and rotor is increased, the displacement of the bearing supporting the rotating shaft increases accordingly, which leads to a corresponding shortening of the bearing's lifespan.

[0010] Furthermore, when the speed of the impeller and rotor is increased, the size of the stator and rotor decreases, which further reduces the support strength of the rotating shaft supporting the rotor, resulting in a corresponding increase in the wear of the bearings.

[0011] In addition, when a portion of the air passing through the impeller is moved toward the stator and rotor to cool the stator and rotor, there is an increase in airflow resistance, which reduces the output (efficiency) of the motor.

[0012] Existing technical documents

[0013] Patent documents

[0014] Patent Document 1: KR 1020130005653A

[0015] Patent Document 2: KR 1020110048796A Summary of the Invention

[0016] Therefore, the object of the present invention is to provide a motor assembly capable of discharging heated air to the outside of a diffuser.

[0017] Another object of the present invention is to provide a motor assembly capable of suppressing vibrations that occur in the bearings.

[0018] Another object of the present invention is to provide a motor assembly capable of promoting bearing cooling.

[0019] Another object of the present invention is to provide a motor assembly capable of increasing the heat exchange area of ​​the bearing.

[0020] To solve the problems described above, the motor assembly of the present invention is characterized in that a first diffuser and a second diffuser are provided on the downstream side of the impeller, and a connecting portion is provided on the hub of the second diffuser to connect the inside and outside of the hub of the second diffuser.

[0021] More specifically, a first diffuser and a second diffuser are provided on the downstream side along the axial direction of the impeller, a motor is provided on the downstream side of the second diffuser, and a connecting portion is provided in the second diffuser to connect the inside and outside of the hub of the second diffuser, so that the air inside the hub of the second diffuser heated by the motor can be discharged to the outside of the second diffuser through the connecting portion.

[0022] An impeller cover is provided on the outside of the impeller and the first diffuser.

[0023] The downstream end of the impeller cover is joined to the outer wall of the second diffuser.

[0024] With this configuration, a relatively low-pressure airflow path is formed between the inside of the impeller cover and the outside of the hub of the second diffuser.

[0025] As a result, the air inside the hub of the second diffuser, which has a relatively high pressure, moves rapidly toward the airflow path through the connecting portion, and can form an airflow inside the hub that moves toward the connecting portion while contacting the motor, thereby promoting the cooling of the motor.

[0026] In addition, the motor can maintain a relatively low temperature during operation, thereby reducing the adverse effects caused by high temperature.

[0027] The first diffuser includes: a hub; and a plurality of blades disposed around the periphery of the hub.

[0028] Therefore, since the first diffuser does not have an outer wall at its outer end along the radial direction of the plurality of blades, the mold used to form the plurality of blades can be radially close to the first diffuser, thereby making the first diffuser easy to manufacture.

[0029] Normally, when the motor temperature is high, the resistance of the stator coil increases, which may reduce the output. However, the motor in this embodiment maintains a relatively low temperature during operation, thus suppressing the increase in the resistance of the stator coil and thereby improving the output.

[0030] The second diffuser is provided with a bearing housing that accommodates a bearing, the bearing supporting the rotating shaft of the motor.

[0031] This promotes the cooling of the bearing.

[0032] In addition, the second diffuser is formed of a component with better thermal conductivity than the first diffuser.

[0033] This promotes heat dissipation from the second diffuser, thereby further promoting the cooling of the bearing.

[0034] An embodiment of the present invention provides a motor assembly comprising: an impeller; a first diffuser disposed downstream of the impeller; a second diffuser disposed downstream of the first diffuser; an impeller cover coupled to the second diffuser to accommodate the impeller and the first diffuser within the impeller cover; and a motor disposed downstream of the second diffuser to drive the impeller to rotate. The second diffuser comprises: a hub; an outer wall concentrically disposed outside the hub; and a plurality of blades, one side of which is connected to the hub and the other side to the outer wall. The impeller cover is coupled to the outer wall of the second diffuser, and a communicating portion is provided in the hub of the second diffuser to connect the interior and exterior of the hub.

[0035] Therefore, the air between the second diffuser and the motor can be discharged to the outside of the second diffuser through the connecting portion.

[0036] With this configuration, during operation, the air heated by the motor can be discharged to the outside of the second diffuser through the connecting portion, thereby promoting the cooling of the motor.

[0037] Since the impeller cover is combined with the outer wall of the second diffuser, a relatively low-pressure airflow path is formed outside the hub of the second diffuser. Therefore, the air inside the hub of the second diffuser, which has a relatively high pressure, can move rapidly into the airflow path through the connecting part, thereby promoting the cooling of the motor.

[0038] In addition, the motor can maintain a relatively low temperature during operation, thereby reducing the adverse effects caused by high temperature.

[0039] Normally, when the motor temperature is high, the resistance of the stator coil increases, which may reduce the output. However, the motor in this embodiment can maintain a relatively low temperature during operation, thus suppressing the increase in the resistance of the stator coil and thereby improving the output.

[0040] In addition, the first diffuser and the second diffuser can be manufactured separately, which makes it easy to manufacture the diffuser.

[0041] In particular, the first diffuser has a plurality of blades arranged around the hub, and no outer wall is provided on the outside of the plurality of blades of the first diffuser, so the first diffuser can be easily manufactured.

[0042] In one embodiment of the present invention, the first diffuser includes: a cylindrical hub with an opening on one side along the axial direction; and a plurality of blades disposed on the outer wall of the hub of the first diffuser, wherein the hub of the second diffuser is inserted into the interior of the hub of the first diffuser to contact the hub surface of the first diffuser.

[0043] This improves the bonding force between the first diffuser and the second diffuser.

[0044] With this structure, when an external force is applied to the first diffuser and the second diffuser, deformation of the first diffuser and the second diffuser can be suppressed.

[0045] In one embodiment of the present invention, the impeller includes: a hub; and a plurality of blades that protrude radially from the periphery of the hub and are circumferentially spaced.

[0046] The impeller has a conical shape.

[0047] The impeller is constructed such that the outer diameter gradually increases from the upstream end to the downstream end.

[0048] In one embodiment of the present invention, a bearing housing is provided in the hub of the second diffuser.

[0049] Therefore, the bearing housing improves the support strength through the hub of the first diffuser that is joined to each other in surface contact, thereby suppressing deformation.

[0050] In one embodiment of the present invention, the second diffuser is formed of a component with better thermal conductivity than the first diffuser.

[0051] This promotes cooling of the bearing housing and the bearing itself.

[0052] In one embodiment of the present invention, the first diffuser may be formed of a synthetic resin component, and the second diffuser may be formed of a metal component.

[0053] The second diffuser may be formed from an aluminum component.

[0054] This further promotes the cooling of the bearing housing and the bearing.

[0055] In one embodiment of the present invention, the second diffuser is provided with protruding heat sinks to increase the surface area.

[0056] This further promotes the cooling of the bearing.

[0057] In one embodiment of the present invention, the heat sink has a radial heat sink, one end of which is connected to the periphery of the bearing housing, and the other end is arranged radially.

[0058] Therefore, the radial heat sink can promote the dissipation of heat energy in the bearing housing.

[0059] In addition, one end of the bearing housing can be supported by the radial heat sink connected to the periphery of the bearing housing, thereby improving the support strength of the bearing housing.

[0060] With this structure, vibration and displacement of the bearing housed inside the bearing housing are suppressed, thereby suppressing wear of the bearing.

[0061] In one embodiment of the present invention, the heat sink includes a circumferential heat sink arranged circumferentially on the inner surface of the hub of the second diffuser.

[0062] This improves the rigidity of the hub of the second diffuser.

[0063] With this construction, vibration and displacement of the bearing housed in the bearing housing are suppressed, thereby suppressing wear of the bearing.

[0064] In addition, it promotes the dissipation of heat energy in the bearing housing, thereby promoting the cooling of the bearing provided in the bearing housing.

[0065] In one embodiment of the present invention, the motor includes: a stator; and a rotor rotatably disposed inside the stator, wherein a stator engagement portion engaging with the stator is provided at the hub of the second diffuser.

[0066] This allows for a stable bonding force between the stator and the second diffuser.

[0067] In one embodiment of the present invention, the stator joint is composed of a plurality of joints spaced apart circumferentially along the stator.

[0068] This increases the bonding force between the stator and the second diffuser.

[0069] The stator joint includes an outer peripheral surface contact portion that is in surface contact with the outer peripheral surface of the stator.

[0070] This allows for a more stable maintenance of the connection between the stator and the second diffuser.

[0071] In one embodiment of the present invention, the stator joint includes an end face contact portion that contacts one end face of the stator along the axial direction.

[0072] This allows for the suppression of axial clearance in the stator and the second diffuser.

[0073] In one embodiment of the present invention, the stator joint has a radial section, one end of which is connected to the bearing receiving part, and the other end extends radially.

[0074] This allows for a further increase in the rigidity of the bearing housing.

[0075] In one embodiment of the present invention, the stator joint includes an axial section extending axially from the radial section, and the outer peripheral surface contact portion is formed on the inner surface of the axial section.

[0076] This improves the bonding force between the second diffuser and the stator.

[0077] In one embodiment of the present invention, the end face contact portion is formed in the axial region in a manner that protrudes more radially inward than the outer peripheral face contact portion.

[0078] Thus, the bearing housing of the second diffuser is separated from the end of the stator by a predetermined distance.

[0079] With this construction, the temperature rise of the bearing housing and the bearing caused by the heating of the stator coil can be suppressed.

[0080] In one embodiment of the present invention, the second diffuser includes the stator junction and the heat sink.

[0081] This improves the rigidity of the second diffuser and increases the heat dissipation area.

[0082] The stator joint has a larger dimension than the heat sink.

[0083] Specifically, the circumferential amplitude of the stator joint is formed to be significantly larger than that of the heat sink in the circumferential direction.

[0084] In addition, the axial height (amplitude) of the stator joint is formed to be the same as the axial height (amplitude) of the heat sink, or the axial height of the stator joint is formed to be greater than the axial height of the heat sink.

[0085] The stator joint consists of three parts, and radial heat sinks are respectively provided between the radial intervals of the stator joints that are adjacent to each other in the circumferential direction.

[0086] The circumferential heat sinks are respectively provided between the radial intervals of the stator joints that are adjacent to each other in the circumferential direction.

[0087] The radial heat sink is connected to the circumferential heat sink.

[0088] This construction significantly improves the rigidity of the second diffuser.

[0089] In addition, the heat dissipation area of ​​the second diffuser can be significantly increased.

[0090] In one embodiment of the present invention, the first diffuser and the second diffuser are respectively provided with axially extending fastening member insertion holes so that fastening members can be inserted.

[0091] The hubs of the first diffuser and the second diffuser, which are joined together in a face-to-face contact manner, are fastened with fastening members, so that the hubs of the first diffuser and the second diffuser are joined as one unit.

[0092] This can further improve the bonding force between the first diffuser and the second diffuser.

[0093] In one embodiment of the present invention, the plurality of blades of the first diffuser are formed such that the upstream and downstream ends of two adjacent blades in the circumferential direction overlap in the axial direction.

[0094] Specifically, the upstream ends of a plurality of blades of the first diffuser are configured to be spaced apart by a predetermined distance along the circumference of the first diffuser, and the downstream ends of each plurality of blades extend along the circumference of the first diffuser at an inclination relative to the axial direction.

[0095] Thus, the downstream ends of each of the plurality of blades are configured to overlap the upstream end of another adjacent blade by a predetermined length.

[0096] As a result, the air velocity moving through the impeller decreases, and the static pressure increases.

[0097] In one embodiment of the present invention, the plurality of blades of the second diffuser are formed such that the upstream end and the downstream end of two adjacent blades are circumferentially separated.

[0098] Specifically, the upstream ends of the plurality of blades of the second diffuser are configured to be spaced apart at a predetermined interval along the circumference of the second diffuser, and the downstream ends of each of the plurality of blades extend circumferentially and are inclined relative to the axial direction.

[0099] The second diffuser has an axial length shorter than that of the first diffuser, and the downstream ends of two adjacent blades of the second diffuser are circumferentially separated from the upstream ends of another adjacent blade.

[0100] With this construction, the multiple blades of the second diffuser do not overlap, and therefore can be easily manufactured.

[0101] In one embodiment of the present invention, the blades of the second diffuser are configured to be shorter than the blades of the first diffuser.

[0102] In one embodiment of the present invention, the impeller cover includes: an impeller receiving portion for receiving the impeller; an intake portion extending axially from the upstream end of the impeller receiving portion and for drawing in air; and a first diffuser receiving portion extending axially from the downstream end of the impeller receiving portion and for receiving the first diffuser.

[0103] Thus, airflow paths that communicate with each other are formed inside the impeller cover, between the impeller, and between the impeller cover and the first diffuser.

[0104] The impeller housing is formed into a conical shape corresponding to the shape of the impeller, and the suction section and the first diffuser housing are formed into a cylindrical shape.

[0105] In one embodiment of the present invention, the outer end of the blade of the first diffuser is formed as an inner circumferential surface facing the first diffuser housing.

[0106] In one embodiment of the present invention, the outer end of the blade of the first diffuser is formed to contact the inner circumferential surface of the first diffuser housing.

[0107] Therefore, it is possible to suppress the flow loss of air moving between the impeller and the plurality of blades of the first diffuser and the impeller cover.

[0108] In one embodiment of the present invention, the hub of the first diffuser is provided with a through portion extending axially, and the hub of the second diffuser is provided with a protruding portion protruding axially and inserted into the through portion.

[0109] Therefore, by making the hubs of the first diffuser and the second diffuser overlap axially, the axial length of the diffuser can be reduced.

[0110] In one embodiment of the present invention, an anti-rotation protrusion protruding along the axial direction is formed on either of the contact surfaces of the hub of the first diffuser and the hub of the second diffuser, and an anti-rotation protrusion receiving groove for accommodating the anti-rotation protrusion is provided on the other contact surface.

[0111] Therefore, the first diffuser and the second diffuser can be assembled in the correct positions.

[0112] In addition, it can suppress the generation of circumferential clearance in the first and second diffusers.

[0113] In one embodiment of the present invention, a bearing receiving portion for accommodating a bearing is provided on the back side of the protrusion of the second diffuser.

[0114] In one embodiment of the present invention, the connecting portion is formed axially between the blades of the first diffuser and the blades of the second diffuser.

[0115] Specifically, the hub of the second diffuser is constructed to protrude axially from the hub of the first diffuser, and the plurality of blades of the first diffuser and the plurality of blades of the second diffuser are configured to be spaced apart by a predetermined length axially.

[0116] The connecting portion extends through the lower side of the downstream end of the hub of the first diffuser.

[0117] The connecting portion is formed on the downstream side of the plurality of blades of the first diffuser.

[0118] The connecting portion is formed on the upstream side of the plurality of blades of the second diffuser.

[0119] Therefore, it is possible to suppress the suction force (suction efficiency) of the impeller that is hindered by the formation of the connecting part.

[0120] In one embodiment of the present invention, the connecting portion is composed of a plurality of portions spaced circumferentially along the diffuser.

[0121] Specifically, the connecting parts consist of two to fifteen units.

[0122] In one embodiment of the present invention, the hub of the second diffuser includes a cylindrical portion and a disc portion that covers one end of the cylindrical portion.

[0123] The disc portion is disposed at the upstream end of the cylindrical portion based on the direction of air movement via the impeller.

[0124] In one embodiment of the present invention, the connecting portion is configured to include: a radial section, one side of which opens into the interior of the disk portion of the second diffuser, and the other side of which extends radially outward from the cylindrical portion along the disk portion; and an axial section, one side of which communicates with the radial section, and the other side of which extends axially.

[0125] This allows for easy extraction of air from the center of the upstream end of the motor.

[0126] The axial section of the connecting portion can be configured to have a first axial section, which is connected to the radial section and is recessed on the outer surface of the second diffuser.

[0127] The axial section of the connecting portion can be configured to have a second axial section, which is connected to the radial section and is recessed on the inner surface of the hub of the first diffuser.

[0128] In one embodiment of the present invention, the axial interval is configured to include: a first axial interval, recessed on the outer surface of the second diffuser and communicating with the radial interval; and a second axial interval, communicating with the radial interval and recessed on the inner surface of the hub of the first diffuser.

[0129] The first axial section and the second axial section can be configured as flow paths that allow air to move in a coordinated manner.

[0130] Therefore, it is possible to suppress the increase in the thickness of the hub of the first diffuser and / or the hub of the second diffuser due to the formation of the axial section.

[0131] In one embodiment of the present invention, the second diffuser is provided with a support joint portion for the support bracket.

[0132] The bracket is constructed to include: a bearing housing that houses a bearing; and a plurality of legs, one end of which is connected to the bearing housing and the other end of which is bent to be axially arranged.

[0133] A bearing is housed in the bearing housing of the bracket, and the bearing is configured on the downstream side of the rotor with reference to the direction of movement of the air moving through the impeller.

[0134] The plurality of legs of the support are configured to contact the ends of the stator joint of the second diffuser, respectively.

[0135] The plurality of legs can be integrated with the stator joint by fastening components.

[0136] The stator joint is provided with a fastening member joint for threaded engagement of the fastening member.

[0137] Each of the plurality of legs has an axially penetrating fastening member insertion portion for inserting the fastening member.

[0138] As described above, according to an embodiment of the present invention, an impeller, a first diffuser, a second diffuser, an impeller cover, and a motor are combined axially. The second diffuser includes: a hub; an outer wall; and a plurality of blades, one side of which is connected to the periphery of the hub, and the other side is connected to the outer wall. The impeller cover is attached to the outer wall of the second diffuser and is provided with a communicating portion connecting the inside and outside of the hub of the second diffuser, thereby enabling the air inside the second diffuser to be discharged to the outside while suppressing the reduction of the impeller's suction efficiency. This promotes the cooling of the motor.

[0139] Furthermore, the first diffuser is housed inside the impeller cover and, by being constructed to include a hub and a plurality of blades formed around the hub, eliminates the need for an outer wall, thereby making the first diffuser easy to manufacture.

[0140] In addition, by providing a bearing housing in the hub of the second diffuser, the vibration and / or displacement of the bearing can be suppressed.

[0141] In addition, the second diffuser, formed of a component with better thermal conductivity than the first diffuser, can promote the cooling of the bearing.

[0142] Furthermore, by providing heat sinks in the second diffuser, cooling of the bearing housed inside the bearing housing can be further promoted.

[0143] In addition, by providing radially connected heat dissipation fins around the bearing housing of the second diffuser, it is possible to suppress the occurrence of vibration in the bearing housing and promote the cooling of the bearing installed in the bearing housing.

[0144] Furthermore, by providing circumferentially arranged heat sinks at the hub of the second diffuser, the cooling of the bearing can be further promoted.

[0145] Furthermore, by providing a stator engagement portion that engages with the stator at the hub of the second diffuser, the second diffuser and the stator can be concentrically engaged.

[0146] In addition, the stator joint is composed of a plurality of parts, and by providing an outer peripheral surface contact part on the inner surface that contacts the outer peripheral surface of the stator, the bonding force between the second diffuser and the stator can be further improved.

[0147] In addition, the stator joint has an end face contact portion that contacts the end face of the stator along the axial direction, which can suppress the generation of relative clearance along the axial direction.

[0148] Furthermore, by forming the radially protruding end face contact portion on the outer peripheral surface contact portion, the hub of the second diffuser can be axially separated from the end of the stator. This allows the bearing housing of the second diffuser to be axially separated from the stator, thereby suppressing temperature rise.

[0149] In addition, the first diffuser and the second diffuser are joined together by fastening members, thereby improving the bonding force.

[0150] Furthermore, the plurality of blades of the second diffuser are formed such that, in two adjacent blades along the circumferential direction, the upstream end of one blade and the downstream end of the other blade are circumferentially separated, thereby making them easy to manufacture.

[0151] In addition, the connecting portion is formed axially between the blades of the first diffuser and the blades of the second diffuser, thereby suppressing the impeller's suction efficiency from being hindered by the formation of the connecting portion.

[0152] In addition, the connecting portion can easily discharge air from the central region of the motor (stator) through a radially formed section in the radial direction of the disc portion of the hub of the second diffuser and an axially formed section in the axial direction of the hub.

[0153] Furthermore, the axial interval, having a first axial interval formed by a recess on the outer surface of the hub of the second diffuser and a second axial interval formed on the inner surface of the hub of the first diffuser, can suppress the increase in the thickness of the hub of the first diffuser and the hub of the second diffuser due to the formation of the axial interval. Attached Figure Description

[0154] Figure 1 This is a perspective view of a motor assembly according to an embodiment of the present invention.

[0155] Figure 2 yes Figure 1 A cross-sectional view of the motor assembly.

[0156] Figure 3 yes Figure 1 An exploded perspective view of the motor assembly.

[0157] Figure 4 yes Figure 3 A three-dimensional view of the first diffuser.

[0158] Figure 5 yes Figure 3 Side view of the second diffuser.

[0159] Figure 6 yes Figure 5 A cross-sectional view of the second diffuser.

[0160] Figure 7 yes Figure 5 A bottom view of the second diffuser.

[0161] Figure 8 yes Figure 5 A bottom-view stereoscopic view of the second diffuser.

[0162] Figure 9 yes Figure 5 The diagram shows the removal of the outer wall of the second diffuser.

[0163] Figure 10 yes Figure 2 An enlarged view of the connected region.

[0164] Figure 11 yes Figure 9 A cross-sectional view of the connecting region of the second diffuser.

[0165] Figure 12 This is a cross-sectional view of the connecting portion region of the second diffuser of a motor assembly according to another embodiment of the present invention.

[0166] Figure 13 This is a cross-sectional view of the connecting portion region of the second diffuser of a motor assembly according to another embodiment of the present invention.

[0167] Figure 14 This is a bottom perspective view of the second diffuser of a motor assembly according to an embodiment of the present invention.

[0168] Figures 15 to 19 They are Figure 14 Examples of variations of the heat sink.

[0169] Figure 20 This is a cross-sectional view of a motor assembly according to another embodiment of the present invention.

[0170] Figure 21 yes Figure 20 Enlarged view of the main parts. Detailed Implementation

[0171] The embodiments disclosed in this specification will now be described in detail with reference to the accompanying drawings. Throughout this specification, similar structural elements are given the same or similar reference numerals even in different embodiments, and their description is based on the initial description. Unless the context clearly indicates otherwise, the singular expressions used in this specification include the plural expressions. Furthermore, in describing the embodiments disclosed in this specification, detailed descriptions of well-known technologies are omitted when it is determined that a detailed explanation of these technologies would obscure the essence of the disclosed embodiments. It should also be noted that the accompanying drawings are only used to facilitate understanding of the embodiments disclosed in this specification, and the technical ideas disclosed in this specification are not limited to the drawings.

[0172] Figure 1 This is a perspective view of a motor assembly according to an embodiment of the present invention. Figure 2 yes Figure 1 A cross-sectional view of the motor assembly. Figure 3 yes Figure 1 An exploded perspective view of the motor assembly. (See image below.) Figures 1 to 3 As shown, a motor assembly 100 according to an embodiment of the present invention includes: an impeller cover 110, an impeller 130, a first diffuser 160, a second diffuser 190, and a motor 250.

[0173] The impeller cover 110, the impeller 130, the first diffuser 160, the second diffuser 190, and the motor 250 are axially connected.

[0174] In this embodiment, the axial direction refers to the direction parallel to the rotation axis 291 of the motor 250. Figure 1 and Figure 2 In this context, the axial direction is consistent with the vertical direction.

[0175] Specifically, along the axial direction, the first diffuser 160 is coupled to one side (the lower side in the figure) of the impeller 130, and the second diffuser 190 is coupled to one side (the lower side in the figure) of the first diffuser 160.

[0176] An airflow path Pa is formed between the impeller cover 110, the first diffuser 160, and the second diffuser 190 to allow air flowing in through the rotation of the impeller 130 to move.

[0177] Along the axial direction, a motor 250 is attached to one side (the lower side in the figure) of the second diffuser 190.

[0178] The impeller 130 and the first diffuser 160 are housed inside the impeller cover 110.

[0179] The impeller cover 110 is combined with the second diffuser 190.

[0180] As the impeller 130 rotates, air is drawn into the interior of the impeller cover 110 and moves via the first diffuser 160 and the second diffuser 190. The air passing through the second diffuser 190 moves axially toward the radially outward side of the motor 250.

[0181] The impeller 130 includes: a hub 131; and a plurality of blades 133 arranged circumferentially around the periphery of the hub 131.

[0182] For example, based on Figure 1 The impeller 130 can be configured to rotate in a counterclockwise direction.

[0183] For example, the hub 131 of the impeller 130 has a conical cross-section.

[0184] A rotating shaft hole 132 is provided in the center of the hub 131 of the impeller 130 so that the rotating shaft 291 of the motor 250 can be inserted.

[0185] The impeller cover 110 is attached to the outside of the impeller 130.

[0186] The impeller 130, which is capable of rotation, is housed inside the impeller cover 110.

[0187] As the impeller 130 rotates, air is drawn in from the front (upper side in the figure) and expelled from the rear (lower side in the figure) of the impeller cover 110.

[0188] Based on the direction of air movement when the impeller 130 rotates, the front of the air intake of the impeller cover 110 (upper side in the figure) can be called the "upstream side", and the rear of the air exhaust of the impeller cover 110 (lower side) can be called the "downstream side".

[0189] An air intake 112 is formed through the center of the impeller cover 110.

[0190] The impeller cover 110 includes: an impeller receiving portion 113 for receiving the impeller 130, and a first diffuser receiving portion 114 for receiving the first diffuser 160.

[0191] The impeller housing 113 is conical in shape, corresponding to the shape of the impeller 130.

[0192] The impeller cover 110 is provided with an air intake 111.

[0193] The suction section 111 may be formed to extend axially from the upstream end of the impeller housing 113.

[0194] The inlet 112 is formed to extend axially through the interior of the inlet portion 111.

[0195] For example, the inner surface of the suction section 111 can be a circular arc cross-section shape that bulges inward from the center.

[0196] The first diffuser housing 114 is configured to extend axially from the downstream end of the impeller housing 113.

[0197] The suction section 111 is cylindrical in shape with the same outer diameter.

[0198] The impeller housing 113 has a conical cross-section shape with a gradually increasing outer diameter.

[0199] The first diffuser housing 114 is cylindrical in shape with the same outer diameter.

[0200] The impeller cover 110 is combined with the second diffuser 190.

[0201] Specifically, the downstream end of the impeller cover 110 is coupled to the upstream end of the second diffuser 190.

[0202] An insertion portion 115 is provided at the downstream end of the impeller cover 110, into which the upstream end of the second diffuser 190 can be inserted.

[0203] The insertion portion 115 is cut out and formed to expand radially along the inner surface of the impeller cover 110.

[0204] The upstream end of the second diffuser 190 is in axial contact with the insertion portion 115.

[0205] This allows for the suppression of axial movement of the impeller cover 110 and the second diffuser 190.

[0206] The outer periphery of the insertion portion 115 is arranged radially outside the outer wall 197 of the second diffuser 190, which will be described later.

[0207] Along the axial direction, the first diffuser 160 is disposed on one side (the lower side, downstream side in the figure) of the impeller 130.

[0208] The first diffuser 160 is configured to be spaced from the impeller 130 by a predetermined amount along the axial direction so that the impeller 130 can rotate.

[0209] The second diffuser 190 is attached to one side (the lower side in the figure) of the first diffuser 160.

[0210] The first diffuser 160 includes: a hub 161; and a plurality of blades 171 arranged circumferentially around the periphery of the hub 161.

[0211] The first diffuser 160 is disposed inside the impeller cover 110 such that the outer ends of the plurality of blades 171 face the inner circumferential surface of the first diffuser housing 114.

[0212] In this embodiment, the outer ends of the plurality of blades 171 of the first diffuser 160 are in contact with the inner peripheral surface of the first diffuser receiving portion 114.

[0213] This can suppress the flow loss of air that flows into the interior of the impeller cover 110 due to the rotation of the impeller 130.

[0214] The second diffuser 190 includes: a hub 191; an outer wall 197 concentrically disposed around the hub 191; and a plurality of blades 198, one end of which is connected to the hub 191 and the other end of which is connected to the outer wall 197.

[0215] The outer wall 197 is located on the outer side of the downstream end of the hub 191 of the second diffuser 190.

[0216] Specifically, the outer wall 197 is concentrically configured to be spaced a predetermined distance from the outer periphery of the downstream end of the hub 191 of the second diffuser 190.

[0217] A region of the second diffuser 190 (the upper region in the figure) is inserted into the interior of the first diffuser 160.

[0218] Another region of the second diffuser 190 (the lower region in the figure) protrudes outward from the first diffuser 160.

[0219] Specifically, the hub 191 of the second diffuser 190 is inserted into the interior of the hub 161 of the first diffuser 160.

[0220] The outer wall 197 of the second diffuser 190 is exposed to the outside of the first diffuser 160.

[0221] The impeller cover 110 is attached to the outer wall 197 of the second diffuser 190.

[0222] The upstream end of the outer wall 197 of the second diffuser 190 is in axial contact with the end of the insertion portion 115 of the impeller cover 110.

[0223] A region of the motor 250 (the upper region in the figure) is axially inserted into the interior of the second diffuser 190.

[0224] The motor 250 includes a stator 260 and a rotor 290 rotatable relative to the stator 260.

[0225] For example, the stator 260 includes: a stator core 261; and a stator coil 271 wound around the stator core 261.

[0226] A rotor receiving hole 263 is formed inside the stator core 261, and the rotor 290 is rotatably accommodated in the rotor receiving hole 263 with a specified air gap G.

[0227] The rotor receiving hole 263 is formed to extend through the axis.

[0228] A plurality of teeth 264 and grooves 265 are alternately formed circumferentially around the rotor receiving hole 263.

[0229] The stator core 261 is formed by insulatingly stacking a plurality of electric steel plates 262, each of which is provided with a rotor receiving hole 263, a plurality of slots 265 and teeth 264.

[0230] An insulator 281 for insulating the stator coils 271 is provided on the stator core 261. For example, the insulator 281 may be configured to be joined to both sides of the stator core 261 along the axial direction to contact each other.

[0231] For example, the rotor 290 is configured to include: a rotating shaft 291; and a permanent magnet 292, which rotates about the rotating shaft 291.

[0232] The permanent magnet 292 is cylindrical in shape.

[0233] A rotating shaft hole 293 is formed through the center of the permanent magnet 292 so that the rotating shaft 291 can be inserted.

[0234] The rotating shaft 291 is supported by bearing 310 so that it can rotate.

[0235] The bearing 310 can be arranged axially on both sides of the permanent magnet 292.

[0236] For example, the bearing 310 can be implemented as a ball bearing.

[0237] Specifically, the bearing 310 includes: an outer ring; an inner ring concentrically disposed inside the outer ring; and a plurality of balls disposed between the outer ring and the inner ring.

[0238] For example, the bearing 310 includes: a first bearing 310a disposed between the impeller 130 and the rotor 290; and a second bearing 310b disposed axially spaced from the first bearing 310a.

[0239] In this embodiment, the first bearing 310a has a larger size than the second bearing 310b. Specifically, the outer ring 311, inner ring 312, and ball 313 of the first bearing 310a are respectively constructed to be larger than the outer ring 311, inner ring 312, and ball 313 of the second bearing 310b.

[0240] This provides stable support for the impeller 130 and the rotor 290.

[0241] A bracket 330 is attached to one side (the lower side in the figure) of the stator 260.

[0242] For example, the bracket 330 includes: a bearing receiving portion 331 for receiving a bearing 310; and a plurality of legs 332, one end of which is connected to the bearing receiving portion 331 and the other end is bent and arranged axially.

[0243] In this embodiment, the second bearing 310b is accommodated and joined in the bearing receiving portion 331 of the bracket 330.

[0244] For example, the plurality of legs 332 are implemented by three.

[0245] For example, the plurality of legs 332 include: a radial section 3321 extending radially from the bearing housing 331; and an axial section 3322 extending axially from the radial section 3321.

[0246] An inclined portion 3323, which is obliquely cut relative to the axial direction, is provided in the outer boundary region of the radial interval 3321 and the axial interval 3322.

[0247] A fastening member insertion portion 333 is formed through the axial section 3322 to allow a fastening member 335, which is coupled to the second diffuser 190, to be inserted. The fastening member 335 may be configured to be threaded into the second diffuser 190.

[0248] On the other hand, the stator coil 271 is connected to the printed circuit board 350 (PCB).

[0249] For example, the stator coil 271 can be configured to be connected to a three-phase AC power supply.

[0250] The stator coil 271 may include a plurality of phase coils connected to the phase power supply (U phase, V phase, W phase) of the AC power supply.

[0251] In this embodiment, the motor assembly 100 can be implemented as, for example, an ultra-small motor assembly in which the outer diameter of the impeller cover 110 is about 55mm, the outer diameter of the stator 260 is about 40mm, and the outer diameter of the rotor 290 is about 9mm.

[0252] Therefore, the size and weight of the motor assembly 100 can be reduced, so that when the motor assembly 100 of this embodiment is provided in a handheld device, it can be easily installed and used.

[0253] In this embodiment, the stator 260 and rotor 290 can achieve (ultra) high-speed rotation (e.g., 100krpm to 180krpm).

[0254] Thus, despite the reduction in size and weight of the motor assembly 100, it can rotate at a relatively high speed, thereby maintaining the same airflow as the motor assembly before the reduction in size and weight, or ensuring the same or higher airflow direction.

[0255] A plurality of connection terminals 283, each connected to a plurality of phase coils, are provided on one side of the stator 260. A plurality of connection terminal supports 282, supporting the plurality of connection terminals 283, are provided on the stator 260. The connection terminal supports 282 may, for example, be provided on the insulator 281. The plurality of connection terminal supports 282 are configured to be circumferentially spaced. The plurality of connection terminal supports 282 are constructed to extend axially to one side (lower side in the figure). The plurality of connection terminal supports 282 are formed such that the plurality of connection terminals 283 are respectively provided axially on the downstream side of the bracket 330. The plurality of connection terminals 283 may, for example, be respectively disposed between a plurality of legs 332 of the bracket 330.

[0256] The printed circuit board 350 is axially disposed on one side of the bracket 330 (the lower side in the figure).

[0257] For example, the printed circuit board 350 includes: a substrate 351; and circuit components 352 mounted on the substrate 351. For example, an inverter circuit capable of providing three-phase AC power to the stator coil 271 may be provided on the substrate 351.

[0258] For example, the substrate 351 can be in the shape of a disk.

[0259] The substrate 351 is provided with a plurality of connection terminal insertion portions 3511 for the plurality of connection terminals 283 to be inserted and engaged. The plurality of connection terminal insertion portions 3511 are formed through the substrate 351.

[0260] Each of the plurality of connection terminal insertion portions 3511 is provided with a connecting portion 3512 that allows for electrical connection to each of the plurality of connection terminals 283. For example, the connecting portion 3512 can be formed by soldering the connection terminal 283 and the connection terminal insertion portion 3511.

[0261] Figure 4 yes Figure 3 A three-dimensional view of the first diffuser. (See image below.) Figure 4 As shown, the first diffuser 160 includes a hub 161 and a plurality of blades 171.

[0262] For example, the first diffuser 160 is formed of a synthetic resin component.

[0263] This reduces the weight of the first diffuser 160.

[0264] The hub 161 of the first diffuser 160 has a downward-opening cylindrical shape.

[0265] Specifically, the hub 161 of the first diffuser 160 can be shaped to shield the upstream end and open the downstream end based on the direction of air movement through the impeller 130.

[0266] The hub 161 of the first diffuser 160 includes a cylindrical portion 1611 and a disc portion 1612, which is formed to shield one end of the cylindrical portion 1611 along the axial direction.

[0267] In this embodiment, the disk portion 1612 of the first diffuser 160 is disposed at the upstream end of the cylindrical portion 1611.

[0268] A through portion 162 is formed in the center of the hub 161 (disc portion 1612) of the first diffuser 160 so that the protrusion 2001 of the second diffuser 190 (described later) can be inserted.

[0269] The first diffuser 160 can be fastened to the second diffuser 190 by fastening member 165.

[0270] This improves the bonding force between the first diffuser 160 and the second diffuser 190.

[0271] A fastening member insertion hole 163 is formed through the hub 161 of the first diffuser 160 so that the fastening member 165 can be inserted.

[0272] The fastening member insertion hole 163 is composed of a plurality of holes spaced apart from each other circumferentially around the through portion 162.

[0273] A plurality of blades 171 are provided on the outer surface of the hub 161 of the first diffuser 160.

[0274] The plurality of blades 171 are configured to be spaced apart from each other circumferentially.

[0275] For example, the plurality of blades 171 are each configured to be tilted relative to the axial direction.

[0276] Specifically, the plurality of blades 171 are each in the shape of a curved cross section that bulges from the center to the upstream side.

[0277] The plurality of blades 171 are configured such that, with the downstream end positioned in front of the upstream end relative to the upstream end, based on the rotation direction of the impeller 130.

[0278] The plurality of blades 171 of the first diffuser 160 are configured such that the upstream end 1711 and the downstream end 1712 of two adjacent blades 171 overlap each other along the axial direction.

[0279] With the rotation direction of the impeller 130 as a reference, the downstream end 1712 of the rear blade 171 is positioned at the lower front side compared to the upstream end 1711 of the front blade 171. That is, the two adjacent blades of the first diffuser 160 are configured to overlap each other axially by approximately half the blade length.

[0280] Figure 5 yes Figure 3 A side view of the second diffuser. Figure 6 yes Figure 5 A cross-sectional view of the second diffuser. Figure 7 yes Figure 5 A bottom view of the second diffuser. Figure 8 yes Figure 5 A bottom-view perspective of the second diffuser. Figure 9 yes Figure 5 A diagram showing the removal of the outer wall of the second diffuser. (See diagram). Figures 5 to 9 As shown, the second diffuser 190 includes a hub 191, an outer wall 197, and a plurality of blades 198.

[0281] The hub of the second diffuser 190 has a cylindrical shape with an opening on one side (the lower side in the figure).

[0282] The hub 191 of the second diffuser 190 is in the shape of a downward-opening cylindrical shape.

[0283] For example, the hub 191 of the second diffuser 190 includes: a cylindrical portion 192; and a disc portion 193, which is formed to axially shield one end of the cylindrical portion 192.

[0284] The hub 191 of the second diffuser 190 is configured to be inserted into the hub 161 of the first diffuser 160.

[0285] The outer surface of the hub 191 of the second diffuser 190 is configured to be in surface contact with the inner surface of the hub 161 of the first diffuser 160.

[0286] Specifically, the cylindrical portion 192 of the hub 191 of the second diffuser 190 is joined to the inner surface of the cylindrical portion 1611 of the hub 161 of the first diffuser 160 in a surface contact manner.

[0287] The disc portion 193 of the hub 191 of the second diffuser 190 is joined to the inner surface of the disc portion 1612 of the hub 161 of the first diffuser 160 in a surface contact manner.

[0288] The hub 191 of the second diffuser 190 is configured to protrude axially to one side (the lower side in the figure) when combined with the first diffuser 160.

[0289] In this embodiment, either the second diffuser 190 or the first diffuser 160 has an axially protruding anti-rotation protrusion 2006 on its mutual contact surface, and the other has an anti-rotation protrusion receiving groove 166 for the anti-rotation protrusion 2006 to be inserted.

[0290] For example, the anti-rotation protrusion 2006 may be formed on the second diffuser 190.

[0291] The anti-rotation protrusion 2006 is disposed on the radial outer side of the protrusion 2001.

[0292] Specifically, the anti-rotation protrusion 2006 is formed to protrude from the outer surface of the second diffuser 190.

[0293] The anti-rotation protrusion receiving groove 166 can be formed in the first diffuser 160.

[0294] For example, the anti-rotation protrusion receiving groove 166 is formed as an axial recess on the inner surface of the first diffuser 160.

[0295] The anti-rotation protrusion receiving groove 166 is disposed on the radial outer side of the through portion 162.

[0296] The hub 191 of the second diffuser 190 includes: a first section 1921 inserted inside the hub 161 of the first diffuser 160; and a second section 1922 disposed outside the first diffuser 160.

[0297] The second interval 1922 is constructed to protrude further outward from the outer periphery of the first interval 1921 in a radial direction.

[0298] The outer diameter of the second interval 1922 is larger than the outer diameter of the first interval 1921.

[0299] For example, the outer diameter of the second section 1922 can be configured to be the same size as the outer diameter of the hub 161 of the first diffuser 160.

[0300] When the first diffuser 160 and the second diffuser 190 are combined, the lower end of the first diffuser 160 can contact the upper end face of the second interval 1922.

[0301] A bearing housing 2003 is provided in the center of the hub 191 of the second diffuser 190.

[0302] The bearing housing 2003 of the second diffuser 190 is formed on the back side of the protrusion 2001.

[0303] The bearing housing 2003 of the second diffuser is formed to protrude axially from the center inside the hub 191 of the second diffuser 190.

[0304] The bearing housing 2003 is formed on the disc portion 193 of the hub 191 of the second diffuser 190.

[0305] An accommodating space 2004 for accommodating the bearing 310 (first bearing 310a) is formed inside the bearing accommodating portion 2003.

[0306] The second diffuser 190 is formed of a component with better thermal conductivity than the first diffuser 160.

[0307] This promotes cooling of the bearing 310 (first bearing 310a) housed in the bearing housing 2003.

[0308] The second diffuser 190 is formed of a metal component.

[0309] This facilitates heat dissipation from the second diffuser 190.

[0310] In addition, the rigidity of the second diffuser 190 can be improved.

[0311] The second diffuser 190 is formed, for example, of an aluminum (Al) component.

[0312] The protrusion 2001 is provided with a through hole 2002 for the rotating shaft 291 to pass through.

[0313] The protrusion 2001 is inserted axially into the through portion 162 of the first diffuser 160.

[0314] Therefore, by overlapping the first diffuser 160 and the second diffuser 190 along the axial direction, the axial length can be shortened.

[0315] In addition, the generation of lateral clearance in the first diffuser 160 and the second diffuser 190 can be suppressed.

[0316] The second diffuser 190 is provided with a stator engagement portion 195 that engages with the stator 260.

[0317] The stator joint 195 is disposed inside the second diffuser 190.

[0318] The stator joint 195 is composed of a plurality of units spaced circumferentially along the second diffuser 190.

[0319] In this embodiment, the stator coupling portion 195 is composed of three parts.

[0320] For example, the stator joint 195 is formed to protrude from the inner surface of the hub 191 of the second diffuser 190.

[0321] The stator joint 195 is provided with a radial section 1951, one end of which is connected to the outer surface of the bearing housing 2003 and the other end of which extends radially.

[0322] The stator joint 195 is provided with an axial section 1952 extending axially from the radial section 1951.

[0323] The axial section 1952 is configured to protrude radially from the inner circumferential surface of the hub 191 of the second diffuser 190 and be arranged axially.

[0324] The radial section 1951 protrudes axially from the inner surface of the second diffuser 190.

[0325] For example, the radial section 1951 has the same height Hr as the bearing housing 2003.

[0326] The stator joint 195 is provided with an outer peripheral surface contact portion 1953 that is in surface contact with the outer peripheral surface of the stator 260 (stator core 261).

[0327] For example, each of the outer peripheral surface contact portions 1953 is configured to have a radius of curvature corresponding to the outer diameter of the stator core 261.

[0328] Thus, the second diffuser 190 can be concentrically coupled with the stator 260 (stator core 261).

[0329] The bearing housing 2003 of the second diffuser 190 is in the shape of a downward-opening cylindrical section.

[0330] The bearing housing 2003 of the second diffuser 190 is provided with a through hole 2002 for the rotating shaft 291 to pass through.

[0331] The second diffuser 190 is provided with a fastening member engagement portion 1956, which communicates with a fastening member insertion hole 163 provided in the first diffuser 160. For example, the fastening member engagement portion 1956 provided in the hub 191 of the second diffuser 190 can be configured to be threadedly engaged with a fastening member 165 passing through the fastening member insertion hole 163 of the first diffuser 160.

[0332] For example, the fastening member joint 1956 of the second diffuser 190 can pass through the radial interval 1951 formed in the stator joint 195.

[0333] The stator joint 195 is provided with an end face contact portion 1954 that contacts one end (the upper end in the figure) of the stator 260 along the axial direction.

[0334] This allows for the suppression of axial clearance in the second diffuser 190 and the stator 260.

[0335] The end face contact portion 1954 is disposed in the axial section 1952 of the stator joint portion 195.

[0336] With this configuration, the stator 260 and the bearing 310 (first bearing 310a) can be separated by a predetermined distance along the axial direction.

[0337] Therefore, it is possible to suppress the temperature rise of the bearing 310 provided in the second diffuser 190 due to the heat generated in the stator 260.

[0338] The end face contact portion 1954 is formed to be axially spaced from the lower end of the cylindrical portion 192 of the hub 191 of the second diffuser 190.

[0339] The end face contact portion 1954 is formed to be axially spaced from the disc portion 193 of the hub 191.

[0340] like Figure 9As shown, the axial section 1952 is configured to protrude axially from the hub 191 of the second diffuser 190.

[0341] Specifically, the stator joint 195 is configured to protrude downward from the lower end of the hub 191 of the second diffuser 190 (the downstream end of the hub 191).

[0342] Each of the stator joints 195 (axial interval 1952) is provided with a fastening member joint 1955 for threaded engagement with the fastening member 335 engaged in the bracket 330.

[0343] The fastening member joint 1955 of the stator joint 195 forms a predetermined depth along the axial direction from the downstream end of the axial section 1952.

[0344] The plurality of blades 198 of the second diffuser 190 are configured to be shorter than the plurality of blades 171 of the first diffuser 160.

[0345] like Figure 9 As shown, the plurality of blades 198 of the second diffuser 190 are configured such that two blades 198 adjacent to each other in the circumferential direction are separated from each other in the circumferential direction by a predetermined interval.

[0346] Specifically, in two adjacent blades 198, with the rotation direction of the impeller 130 as a reference, the downstream end of the blade located at the rear is spaced further back than the upstream end of the blade located at the front.

[0347] With this construction, the second diffuser 190 can be easily manufactured.

[0348] On the other hand, refer to Figure 6 and Figure 9 A connecting portion 205 connecting the interior and the exterior is provided in the hub 191 of the second diffuser 190.

[0349] This allows the air inside the second diffuser 190 to be discharged to the outside of the second diffuser 190.

[0350] With this configuration, the air inside the second diffuser 190, whose temperature rises due to the heat generated when the motor 250 (stator 260 and rotor 290) is running, is discharged to the outside of the second diffuser 190 via the communication portion 205, thereby reducing the temperature inside the second diffuser 190.

[0351] Because the temperature rise of the stator 260 and rotor 290 is suppressed, the phenomenon that the increased resistance of the stator 260 and rotor 280 hinders the output of the motor 250 when the temperature of the stator 260 and rotor 290 rises can be suppressed. That is, since the stator 260 and rotor 290 of this embodiment operate at a relatively low temperature through the air discharge of the communication portion 205, the output of the motor 250 can be improved.

[0352] The connecting portion 205 may be composed of a plurality of portions spaced circumferentially along the second diffuser 190.

[0353] For example, the connecting portion 205 can be composed of 2 to 15 parts.

[0354] In this embodiment, although the case in which the connecting portion 205 is composed of 9 is illustrated, this is only an example and is not a limitation.

[0355] The connecting portions 205 are respectively formed on the upstream side of a plurality of blades 198 of the second diffuser 190.

[0356] Figure 10 yes Figure 2 An enlarged view of the connected region. Figure 11 yes Figure 9 Cross-sectional view of the connected region. Figure 12 This is a cross-sectional view of the communicating portion region of the second diffuser of a motor assembly according to another embodiment of the present invention. Figure 13 This is a cross-sectional view of the connecting portion region of the second diffuser of a motor assembly according to another embodiment of the present invention.

[0357] like Figure 10 and Figure 11 As shown, the connecting portion 205 is formed as a cylindrical portion 192 that radially penetrates the hub 191 of the second diffuser 190.

[0358] For example, the connecting portion 205 may be in the shape of an elongated hole, which has a length that is approximately longer than the amplitude.

[0359] The connecting portion 205 is configured such that its length is arranged circumferentially along the cylindrical portion 192 of the hub 191 of the second diffuser 190, and its amplitude is arranged axially along the cylindrical portion 192 of the hub 191.

[0360] The connecting portion 205 is arranged axially on one side (the lower side in the figure) of the first diffuser 160.

[0361] The connecting portion 205 is axially disposed on one side (lower side) of the plurality of blades 171 of the first diffuser 160.

[0362] Refer again Figure 9 The connecting portion 205 is formed in the second section 1922 of the cylindrical portion 192 of the second diffuser 190.

[0363] Each of the connecting portions 205 is configured such that the upstream side (upper side) is open along the axial direction.

[0364] The open area on the upstream side of the connecting portion 205 is shielded by the downstream end (lower end) of the first diffuser 160 when the first diffuser 160 and the second diffuser 190 are combined.

[0365] In this embodiment, the connecting portion 205 can be composed of 9 parts as described above.

[0366] Specifically, for example, three of the connecting portions 205 can be formed to penetrate the stator joint portion 195 (axial interval 1952).

[0367] The six connecting portions 205 are respectively formed as cylindrical portions (second intervals 1922) penetrating the hub 191 of the second diffuser 190.

[0368] On the other hand, such as Figure 12 As shown, the second diffuser 190 can be implemented with six connecting portions 205a.

[0369] In this embodiment, three of the six connecting portions 205a can be formed to penetrate the stator joint portion 195 (axial section 1952) radially.

[0370] Three of the six connecting portions 205 can be formed as hubs 191 (second intervals 1922) that radially penetrate the second diffuser 190 so that they can be respectively disposed between the stator joint portions 195.

[0371] In addition, such as Figure 13 As shown, the second diffuser 190 may have twelve connecting portions 205b.

[0372] Three of the twelve connecting portions 205b can be formed to penetrate the stator joint portion 195.

[0373] Nine of the twelve connecting portions 205b can be configured such that three are arranged between each of the stator joint portions 195.

[0374] With this configuration, when the impeller cover 110, impeller 130, first diffuser 160, second diffuser 190 and motor 250 are combined together, the second diffuser 190 can be inserted and combined inside the first diffuser 160, and the bearing 310 (first bearing 310a) can be accommodated and combined in the bearing receiving portion 2003 of the second diffuser 190.

[0375] The stator 260 can be inserted into the second diffuser 190 along the axial direction, and the rotor 290 can be inserted into the stator 260.

[0376] The upper end of the rotating shaft 291 of the rotor 290 is coupled to pass through the first bearing 310a, and the impeller 130 is coupled to the upper end of the rotating shaft 291.

[0377] The impeller cover 110 is attached to the outer wall 197 of the second diffuser 190.

[0378] The bearing 310 (second bearing 310b) is attached to the lower region of the rotating shaft 291 of the rotor 290, and the second bearing 310b is inserted into the bearing receiving portion 331 of the bracket 330.

[0379] The plurality of legs 332 of the bracket 330 are fixedly connected to the stator joint 195 by fastening members 335.

[0380] The stator 260 connection terminal support portion 282 is respectively arranged between the plurality of legs 332 of the bracket 330, and the connection terminal 283 protruding axially towards the lower side of the bracket 330 is connected to the printed circuit board 350 in a manner that enables power transmission. Thus, a three-phase AC power supply can be applied to the stator coil 271.

[0381] On the other hand, when operation begins and power is applied to the stator coil 271, the stator coil 271 generates magnetic force, and the rotor 290 rotates around the rotation axis 291 through the interaction between the magnetic force of the permanent magnet 292 and the magnetic force of the stator coil 271.

[0382] When the impeller 130 is rotated by the rotation of the rotor 290, air is drawn into the interior of the impeller cover 110 through the suction port 112.

[0383] Air drawn into the interior of the impeller cover 110 is guided axially by a plurality of blades 171 of the first diffuser 160 and a plurality of blades 198 of the second diffuser 190 and discharged axially towards the downstream side of the second diffuser 190. The discharged air moves axially downward on the radially outer side of the stator 260.

[0384] On the other hand, when the impeller 130 starts operating and rotates, the air velocity on the downstream side of the impeller 130 increases and its pressure decreases. At this time, the airflow path Pa on the outer side of the second diffuser 190 in the radial direction is in a relatively low pressure state, so the air inside the hub 191 of the second diffuser 190 moves to the outside of the hub 191 of the second diffuser 190 via the connecting portion 205.

[0385] As the impeller 130 rotates, air inside the hub 191 of the second diffuser 190 continuously flows out through the connecting portion 205, thus the air continuously moves towards the connecting portion 205 via the upper region of the motor 250 (stator 260 and rotor 290). Consequently, the motor 250 (stator 260 and rotor 290) can be continuously cooled by the air continuously moving towards the connecting portion 205. Therefore, the stator 260 and rotor 290 can maintain a relatively low temperature and suppress the increase in resistance caused by temperature rise, thereby improving the output of the motor 250.

[0386] Figure 14 This is a bottom perspective view of the second diffuser of a motor assembly according to an embodiment of the present invention. Figures 15 to 19 They are Figure 14 Examples of variations of the heat sink.

[0387] like Figure 14 As shown, the second diffuser 190a of the motor assembly of one embodiment of the present invention is constructed in the same manner as described above, including: a hub 191; an outer wall 197 concentrically disposed on the outer side of the hub 191; and a plurality of blades 198, one end of which is connected to the hub 191 and the other end of which is connected to the outer wall 197.

[0388] The hub 191 of the second diffuser 190 is provided with a bearing housing 2003 for accommodating the bearing 310.

[0389] The second diffuser 190 is provided with a stator engagement portion 195 that engages with the stator 260.

[0390] The stator connection portion 195 includes: a radial section 1951, one end of which is connected to the bearing receiving portion 2003 and extends radially; and an axial section 1952, which extends axially from the radial section 1951.

[0391] The stator joint 195 includes: an outer peripheral surface contact portion 1953, which contacts the outer peripheral surface of the stator 260; and an end surface contact portion 1954, which contacts one end surface of the stator 260 along the axial direction.

[0392] The second diffuser 190 is provided with a connecting portion 205 that connects the inside and outside of the hub 191 of the second diffuser 190.

[0393] The second diffuser 190 is formed of a metal component.

[0394] The second diffuser 190 is formed of an aluminum (Al) component.

[0395] On the other hand, in this embodiment, the second diffuser 190 is provided with protruding heat sinks 220 to increase the surface area.

[0396] For example, the heat sink 220 is provided with a radial heat sink 221, one end of which is connected to the periphery of the bearing housing 2003, and the other end of which extends radially.

[0397] This facilitates heat dissipation in the bearing housing 2003.

[0398] In addition, the support strength of the bearing housing 2003 can be improved.

[0399] With this structure, vibration of the bearing 310 (first bearing 310a) disposed inside the bearing housing 2003 can be suppressed. In addition, cooling of the bearing 310 (first bearing 310a) disposed inside the bearing housing 2003 can be promoted.

[0400] For example, the radial heat sinks 221 can be arranged circumferentially between the stator joints 195.

[0401] In this embodiment, the radial heat sink 221 may consist of three components.

[0402] The radial heat sink 221 has the same height along the axial direction as the stator joint 195.

[0403] In this embodiment, the heat sink 220 is provided with circumferential heat sinks 222 arranged circumferentially around the bearing receiving portion 2003.

[0404] This facilitates heat dissipation from the second diffuser 190.

[0405] In addition, the rigidity of the second diffuser 190 can be improved.

[0406] With this construction, vibrations of the bearing 310 (first bearing 310a) located inside the bearing housing 2003 can be suppressed.

[0407] In addition, it can promote the cooling of the bearing 310 (first bearing 310a) disposed inside the bearing housing 2003.

[0408] The circumferential heat sink 222 is composed of a plurality of circumferentially arranged around the bearing housing 2003.

[0409] The circumferential heat sink 222 can be formed in the same number as the radial heat sink 221. In this embodiment, the circumferential heat sink 222 consists of three.

[0410] For example, the circumferential heat sink 222 can be configured such that the axial protrusion height Hc of the inner surface of the hub 191 is less than the axial protrusion height Hr of the radial heat sink 221 from the inner surface of the hub 191.

[0411] The radial heat sink 221 is configured to protrude more axially from the inner surface of the hub 191 than the circumferential heat sink 222.

[0412] Among them, such as Figure 15 As shown, the heat sink 220a in this embodiment may be provided with a radial heat sink 221a and a circumferential heat sink 222a that have the same protrusion height along the axial direction from the inner surface of the hub 191.

[0413] In this embodiment, for example, the radial heat sink 221a and the circumferential heat sink 222a are configured to have the same height as the stator joint 195.

[0414] In addition, such as Figure 16 As shown, the heat sink 220b in this embodiment is provided with a radial heat sink 221b and a circumferential heat sink 222b that protrude axially from the inner surface of the hub 191. In this embodiment, the protrusion height Hr of the radial heat sink 221b protruding axially from the disk portion 193 of the hub 191 is formed to be the same as the protrusion height Hc of the circumferential heat sink 222b. The protrusion heights Hr of the radial heat sink 221b and Hc of the circumferential heat sink 222b are configured to be smaller than the protrusion height Hs of the stator joint portion 195 protruding axially from the disk portion 193 of the hub 191.

[0415] On the other hand, the heat sink 220 may be provided with radial heat sinks 221 and circumferential heat sinks 222 formed in different numbers.

[0416] like Figure 17 As shown, the heat sink 220c is constructed to include three circumferential heat sinks 222c and six radial heat sinks 221c. In this embodiment, two radial heat sinks 221c may be constructed between the stator joint portions 195 that are adjacent to each other circumferentially. The circumferential heat sinks 222c may be arranged circumferentially between the radial heat sinks 221c.

[0417] The circumferential heat sink 222c is configured to connect the stator joint 195 and the radial heat sink 221c that are adjacent to each other in the circumferential direction, or to connect two adjacent radial heat sinks 221c.

[0418] like Figure 18 As shown, the heat sink 220d is constructed to include three circumferential heat sinks 222d and nine radial heat sinks 221d. In this embodiment, three radial heat sinks 221d can be constructed between two stator joints 195 that are adjacent to each other in the circumferential direction. Each of the circumferential heat sinks 222d is disposed between two adjacent radial heat sinks 221d.

[0419] Each of the circumferential heat sinks 222d is configured to connect the stator joint 195 and the radial heat sink 221d that are adjacent to each other, or to connect two radial heat sinks 221d that are adjacent to each other.

[0420] On the other hand, such as Figure 19 As shown, the heat sink 220e is constructed to include: two circumferential heat sinks 222e, which are radially spaced around the bearing housing 2003; and three radial heat sinks 221e, which are respectively disposed between two adjacent stator joints 195.

[0421] Each circumferential heat sink 222e is configured such that one end is connected to the stator joint 195, and the other end is connected to the radial heat sink 221e respectively.

[0422] Figure 20 This is a cross-sectional view of a motor assembly according to another embodiment of the present invention. Figure 21 yes Figure 20 Enlarged view of the main parts. The motor assembly 100a of this embodiment includes: impeller 130, impeller cover 110, first diffuser 160, second diffuser 190b, and motor 250.

[0423] The impeller cover 110, the impeller 130, the first diffuser 160, the second diffuser 190b, and the motor 250 are axially connected to each other.

[0424] The impeller 130 is housed inside the impeller cover 110, and the first diffuser 160 is coupled to the downstream side of the impeller 130. A second diffuser 190b is coupled to the first diffuser 160, and the impeller cover 110 is coupled to the second diffuser 190b to house the impeller 130 and the first diffuser 160 internally.

[0425] An airflow path Pa is formed between the impeller cover 110, the first diffuser 160, and the second diffuser 190b to allow air flowing in due to the rotation of the impeller 130 to move.

[0426] The motor 250 is integrated into the second diffuser 190b.

[0427] The motor 250 includes a stator 260 and a rotor 290, which is rotatably housed relative to the stator 260 with a defined air gap G.

[0428] The stator 260 includes: a stator core 261; and a stator coil 271 wound around the stator core 261.

[0429] The stator 260 is configured such that one end is electrically connected to the stator coil 271, and the other end is provided with a plurality of connecting terminals 283 extending along the axial direction.

[0430] The plurality of connection terminals 283 are electrically connected to the printed circuit board 350. The printed circuit board 350 includes: a substrate 351; and a plurality of circuit components 352 disposed on the substrate 351. For example, the printed circuit board 350 may be configured to provide an inverter circuit to provide three-phase AC power to the stator coil 271.

[0431] The rotor 290 includes a rotating shaft 291 and a permanent magnet 292, rotating about the rotating shaft 291. The rotating shaft 291 is supported by a bearing 310 and is rotatable. The bearing 310 includes a first bearing 310a and a second bearing 310b respectively disposed on both sides (upper and lower sides in the figure) of the permanent magnet 292 along the axial direction. The first bearing 310a may be constructed to be larger than the second bearing 310b.

[0432] The impeller 130 includes: a hub 131; and a plurality of blades 133 disposed around the hub 131.

[0433] The first diffuser 160 includes: a cylindrical hub 161; and a plurality of blades 171 disposed on the outer surface of the hub 161.

[0434] The radially outer ends of the plurality of blades 171 of the first diffuser 160 face the inner circumferential surface of the impeller cover 110. Specifically, the radially outer ends of the plurality of blades 171 of the first diffuser 160 are configured to contact the inner circumferential surface of the impeller cover 110.

[0435] On the other hand, the second diffuser 190b includes: a cylindrical hub 191; an outer wall 197 concentrically disposed on the outside of the hub 191; and a plurality of blades 198, one end of which is connected to the hub 191 and the other end of which is connected to the outer wall 197.

[0436] The hub 191 of the second diffuser 190b is configured to be inserted into the hub 161 of the first diffuser 160.

[0437] An anti-rotation protrusion 2006 protruding axially is provided on either of the contact surfaces of the first diffuser 160 and the second diffuser 190b, and an anti-rotation protrusion receiving groove 166 is provided on the other for the anti-rotation protrusion 2006 to be inserted.

[0438] The anti-rotation protrusion 2006 is formed to protrude axially on the outer surface of the second diffuser 190b, and the anti-rotation protrusion receiving groove 166 is formed to be recessed axially on the inner surface of the first diffuser 160.

[0439] The hub 191 of the second diffuser 190b includes: a cylindrical portion 192; and a disc portion 193, which is formed to shield one end of the cylindrical portion 192 along the axial direction.

[0440] The cylindrical portion 192 of the hub 191 of the second diffuser 190b includes: a first section 1921 inserted into the interior of the first diffuser 160; and a second section 1922 protruding from the exterior of the first diffuser 160.

[0441] A bearing receiving portion 2003 is provided in the hub 191 (disc portion 193) of the second diffuser 190b to accommodate the bearing 310 (first bearing 310a).

[0442] A stator engagement portion 195 is formed in the second diffuser 190b for engaging with the stator 260.

[0443] The stator joint 195 is configured to include: a radial section 1951, one end of which is connected to the bearing receiving section 2003 and the other end of which extends radially; and an axial section 1952, which extends axially from the end of the radial section 1951.

[0444] Along the axial direction, a bracket 330 is provided on one side (the lower side in the figure) of the motor 250 to accommodate and support the bearing 310 (the second bearing 310b).

[0445] The support 330 includes: a bearing receiving portion 331 for receiving the bearing 310 (second bearing 310b); and a plurality of legs 332, one end of which is connected to the bearing receiving portion 331, and the other end is bent and arranged axially. The plurality of legs 332 are respectively coupled to the stator coupling portion 195 of the second diffuser 190b.

[0446] On the other hand, in this embodiment, a connecting portion 205c is provided in the hub 191 of the second diffuser 190b to connect the interior and exterior of the hub 191.

[0447] The connecting portion 205c is configured to include: a radial section 210, which is formed to extend radially outward from the disc portion 193 of the hub 191 of the second diffuser 190b to the outside of the cylindrical portion 192; and an axial section 215, which communicates with the radial section 210 on one side and extends axially on the other side.

[0448] In this embodiment, the radial section 210 of the connecting portion 205c is provided with an inlet 211 that communicates with the interior of the disc portion 193 of the hub of the second diffuser 190b.

[0449] The radial section 210 of the connecting portion 205c is provided with an external opening 212 that communicates with the outside of the hub 191.

[0450] Therefore, the air inside the hub 191 of the second diffuser 190b can move to the outside of the hub 191 via the inlet 211, the radial section 210, and the external opening 212.

[0451] In this embodiment, the connecting portion 205c can be composed of a plurality of portions spaced circumferentially along the second diffuser 190b. For example, the connecting portion 205c can be formed as 2 to 15 portions.

[0452] In this embodiment, a portion (e.g., three) of the plurality of connecting portions 205c may be formed in the stator joint portion 195.

[0453] The axial interval 215 is provided with a first axial interval 2151, which is recessed on the outer surface of the cylindrical portion 192 of the hub 191 of the second diffuser 190b.

[0454] The first axial section 2151 is provided with an outlet 2153 for air to flow out.

[0455] The outlet 2153 is formed to open outward between the plurality of blades 171 of the first diffuser 160 and the plurality of blades 198 of the second diffuser 190b.

[0456] Therefore, air moving toward the outside of the hub 191 of the second diffuser 190b via the inlet 211 and radial interval 210 can move along the first axial interval 2151 and flow out toward the airflow path Pa via the outlet 2153.

[0457] The axial section 215 is provided with a second axial section 2152, which is formed by a recess on the inner surface of the hub 161 of the first diffuser 160.

[0458] The second axial section 2152 forms a flow path for air movement that cooperates with the first axial section 2151.

[0459] In this embodiment, the axial interval 215 is configured to simultaneously have the first axial interval 2151 and the second axial interval 2152, thereby suppressing the increase in the thickness of the hub 161 of the first diffuser 160 and the hub 191 of the second diffuser 190b, respectively.

[0460] The upstream end of the second axial section 2152 is formed to correspond to the outer opening 212 of the radial section 210, and the downstream end extends to the downstream end of the first diffuser 160.

[0461] With this configuration, when power is applied to the stator coil 271 to start operation, the rotor 290 rotates around the rotation axis 291 by the interaction of the magnetic force generated by the stator coil 271 and the magnetic force of the permanent magnet 292.

[0462] When the rotating shaft 291 rotates, the impeller 130 rotates and draws in air via the intake port 112 inside the impeller cover 110. The drawn-in air moves downstream along the outside of the motor 250 via the impeller 130, the first diffuser 160, and the second diffuser 190b.

[0463] On the other hand, if the impeller 130 rotates, the pressure on the downstream side of the impeller 130 decreases relatively, and the air heated by the motor 250 between the second diffuser 190b and the motor 250 moves along the inlet 211, the radial section 210, and the axial section 215, and then flows out to the air flow path Pa via the outlet 2153.

[0464] As a result, relatively cool air from the vicinity of the motor 250 flows into the space between the hub 191 of the second diffuser 190b and the motor 250. During this process, the relatively cool air comes into contact with the motor 250, thereby cooling the motor 250.

[0465] With this configuration, as the impeller 130 rotates, the air between the second diffuser 190b and the motor 250 continuously flows out to the outside of the hub 191 of the second diffuser 190b via the connecting portion 205c, continuously cooling the motor 250, thereby enabling the motor 250 to operate at a relatively low temperature.

[0466] Therefore, the increase in resistance caused by the high temperature of the motor 250 is suppressed, thereby improving the output of the motor 250.

[0467] The above description illustrates and describes specific embodiments of the present invention. However, the present invention can be implemented in various forms without departing from its spirit or essential characteristics, and therefore the embodiments described above should not be limited to the specific content used to implement the invention.

[0468] Furthermore, even the embodiments not listed individually in the detailed description above should be broadly interpreted within the scope of the technical concept defined in the appended claims. Moreover, all modifications and variations included within the scope of the above claims and their equivalents should be included in the appended claims.

Claims

1. A motor assembly, in, include: impeller; A first diffuser is disposed on the downstream side of the impeller; The second diffuser is disposed downstream of the first diffuser; An impeller cover, combined with the second diffuser, to accommodate the impeller and the first diffuser within the impeller cover; and A motor is located on the downstream side of the second diffuser to drive the impeller to rotate; The second diffuser includes: Wheel hub; The outer wall is concentrically disposed on the outer side of the hub; and A plurality of blades, one side of which is connected to the hub and the other side of which is connected to the outer wall; The impeller cover is integrated with the outer wall of the second diffuser. The hub of the second diffuser includes: cylindrical part; and The disc portion is formed to cover one end of the cylindrical portion; The hub of the second diffuser also has a connecting portion that connects the interior and exterior of the hub. The connecting portion includes: A radial section, opening into the interior of the disk portion on one side and extending radially outward from the cylindrical portion on the other side; and The axial section is connected to the radial section on one side and extends axially on the other side.

2. The motor assembly according to claim 1, wherein, The first diffuser includes: A cylindrical hub with an opening on one side along the axial direction; and Multiple blades are disposed on the outer wall of the hub of the first diffuser. The hub of the second diffuser is inserted into the interior of the hub of the first diffuser to contact the hub surface of the first diffuser.

3. The motor assembly according to claim 2, wherein, A bearing housing is provided in the hub of the second diffuser.

4. The motor assembly according to claim 3, wherein, The second diffuser is formed of a component with better thermal conductivity than the first diffuser.

5. The motor assembly according to claim 3, wherein, The second diffuser has protruding heat sinks to increase the surface area.

6. The motor assembly according to claim 5, wherein, The heat sink has radial heat sinks, one end of which is connected to the periphery of the bearing housing, and the other end is arranged radially.

7. The motor assembly according to claim 5, wherein, The heat sink has circumferential heat sinks, which are arranged circumferentially on the inner surface of the hub of the second diffuser.

8. The motor assembly according to claim 5, wherein, The motor includes: Stator; and The rotor is rotatably disposed inside the stator. The hub of the second diffuser is provided with a stator engagement portion that engages with the stator.

9. The motor assembly according to claim 8, wherein, The stator joints are multiple and spaced apart along the circumference of the stator. The stator joint has an outer peripheral surface contact portion that is in surface contact with the outer peripheral surface of the stator.

10. The motor assembly according to claim 9, wherein, The stator joint has an end face contact portion that contacts one end face of the stator along the axial direction.

11. The motor assembly according to claim 10, wherein, The stator joint has a radial section, one end of which is connected to the bearing receiving part, and the other end extends radially.

12. The motor assembly according to claim 11, wherein, The stator joint has an axial section extending axially from the radial section of the stator joint. The outer peripheral contact portion is formed on the inner surface of the axial section of the stator joint.

13. The motor assembly according to claim 12, wherein, The end face contact portion is formed in the axial region of the stator joint in a manner that protrudes more radially inward than the outer peripheral face contact portion.

14. The motor assembly according to claim 7, wherein, The first diffuser and the second diffuser each have axially extending fastening member insertion holes for fastening members to be inserted.

15. The motor assembly according to claim 2, wherein, The plurality of blades of the first diffuser are configured such that, in two circumferentially adjacent blades, the upstream end of one blade and the downstream end of the other blade overlap axially.

16. The motor assembly according to claim 15, wherein, The plurality of blades of the second diffuser are configured such that, in two adjacent blades along the circumferential direction, the upstream end of one blade and the downstream end of the other blade are circumferentially separated.

17. The motor assembly according to claim 2, wherein, The blades of the second diffuser are shorter than the blades of the first diffuser.

18. The motor assembly according to claim 2, wherein, The impeller cover includes: Impeller housing, for accommodating the impeller; The intake section extends axially from the upstream end of the impeller housing to draw in air; and A first diffuser housing extends axially from the downstream end of the impeller housing and houses the first diffuser.

19. The motor assembly according to claim 18, wherein, The impeller housing is formed in a conical shape corresponding to the shape of the impeller, and the suction section and the first diffuser housing are formed in a cylindrical shape.

20. The motor assembly according to claim 18, wherein, The radially outer end of the blade of the first diffuser is formed to face the inner circumferential surface of the first diffuser housing or to contact the inner circumferential surface of the first diffuser housing.

21. The motor assembly according to claim 2, wherein, The hub of the first diffuser has a through section that extends axially. The hub of the second diffuser has a protrusion that protrudes axially and is inserted into the through portion.

22. The motor assembly according to claim 21, wherein, An axially protruding anti-rotation protrusion is formed on either of the contact surfaces of the hubs of the first diffuser and the second diffuser, and an anti-rotation protrusion receiving groove is provided on the other contact surface to accommodate the anti-rotation protrusion.

23. The motor assembly according to claim 21, wherein, A bearing housing is provided on the back side of the protrusion of the second diffuser to accommodate the bearing.

24. The motor assembly according to any one of claims 2 to 23, wherein, The connecting portion is formed axially between the blades of the first diffuser and the blades of the second diffuser.

25. The motor assembly according to any one of claims 1 to 23, wherein, The axial section of the connecting portion includes at least one of a first axial section and a second axial section. The first axial section is recessed on the outer surface of the second diffuser and communicates with the radial section of the connecting portion; The second axial section is recessed on the inner surface of the hub of the first diffuser and communicates with the radial section of the connecting portion.

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