JP7330877B2 - Cooling fan, motor assembly - Google Patents

Description

The present invention relates to a cooling fan and motor assembly.

2. Description of the Related Art Conventionally, an electric motor assembly including an inverter section and a motor section is known. In such an electric motor assembly, the inverter section includes an inverter and an inverter case that houses the inverter. The motor section includes a motor having a rotor and a stator that rotate the drive shaft, and a motor casing that houses the motor.

Since the inverter and the motor are heat sources, when the electric motor assembly is operated, the heat of the inverter is transferred to the inverter case and the temperature of the inverter case becomes high. Similarly, heat from the motor is transferred to the motor casing, which becomes hot. As a result, the motor assembly as a whole becomes very hot.

Therefore, the motor assembly includes a cooling fan fixed to the drive shaft. The cooling fan rotates with the rotation of the drive shaft and cools the outer surface of the inverter case and the outer surface of the motor casing (see, for example, Patent Document 1).

JP 2019-162017 A

In some cooling fans, a lower plate (straightening guide) is provided below the blades in order to increase the rigidity of the blades and to efficiently send the cooling air to the outer peripheral side of the inverter case. In such a case, heat may be trapped between the lower plate and the inverter case, degrading the heat dissipation of the inverter.

SUMMARY OF THE INVENTION It is an object of the present invention to provide a cooling fan and electric motor assembly capable of diffusing the air on the back side of the lower plate of the cooling fan and improving heat dissipation.

A cooling fan according to an aspect of the present invention includes a hub attached to a drive shaft of a rotating machine, blades provided on the peripheral surface of the hub, and provided on the peripheral surface of the hub, the blades having a conical surface. It has a supporting conical lower plate and a back blade provided on the back side of the lower plate.

In the cooling fan described above, the back blade may be radially spaced apart from the peripheral surface of the hub.
In the above cooling fan, the back blade may radially extend to the outer peripheral edge of the lower plate.
In the cooling fan described above, the back blade may axially protrude from a space on the back side of the lower plate.
In the cooling fan described above, the hub, the blades, the lower plate, and the rear blades may be integrally formed.

An electric motor assembly according to an aspect of the present invention includes a drive shaft, a motor that rotates the drive shaft, a motor casing in which the motor is arranged, an inverter that controls the operation of the motor, and A motor assembly comprising: an inverter case in which an inverter is arranged and through which the drive shaft passes; and a cooling fan arranged adjacent to the inverter case and fixed to an end of the drive shaft, wherein the cooling As a fan, it has the cooling fan described above.

In the electric motor assembly described above, the back blade of the cooling fan may rotate at a position axially overlapping at least a portion of the heat generating element of the inverter.

According to the aspect of the present invention, it is possible to diffuse the air on the back side of the lower plate of the cooling fan and improve heat dissipation.

1 is a cross-sectional view of an electric motor assembly according to one embodiment; FIG. It is a left view of the electric motor assembly which concerns on one Embodiment. 4 is an enlarged cross-sectional view of a motor assembly near a cooling fan according to one embodiment; FIG. 1 is a perspective view of the front side of a cooling fan according to one embodiment; FIG. FIG. 4 is a perspective view of the back side of a cooling fan according to one embodiment; 5 is a cross-sectional view taken along the line AA shown in FIG. 4; FIG. As a comparative example, it is an analysis diagram showing the flow of air when the back blade does not protrude from the space on the back side of the lower plate in the axial direction. As an example, it is an analysis diagram showing the flow of air when the back blade protrudes in the axial direction from the space on the back side of the lower plate. It is a principal part enlarged view which shows the modification of the back blade|wing which concerns on one Embodiment.

An embodiment of the present invention will be described below with reference to the drawings.
FIG. 1 is a cross-sectional view of an electric motor assembly 1 according to one embodiment. FIG. 2 is a left side view of the electric motor assembly 1 according to one embodiment.
As shown in FIG. 1, the electric motor assembly 1 is an electric motor having an integrated structure in which an inverter 20 is built. The electric motor assembly 1 includes a motor section 2 and an inverter section 3 .

The electric motor assembly 1 has a drive shaft 5 rotated by a motor section 2 . The drive shaft 5 is arranged to pass through the inverter section 3 . In the following description, the direction in which the central axis O of the drive shaft 5 extends is called the axial direction, the direction perpendicular to the central axis O is called the radial direction, and the direction of rotation around the central axis O is called the circumferential direction.

The motor unit 2 includes a motor 8 including a rotor 6 (rotor) and a stator 7 (stator) that rotate the drive shaft 5, and a motor casing 10 that accommodates the rotor 6 and the stator 7. The inverter unit 3 includes an inverter 20 that controls the operation (rotational speed) of the motor 8, and an inverter case 21 that accommodates the inverter 20 and is connected in series with the motor casing 10 in the axial direction. .

Drive shaft 5 extends through motor casing 10 and inverter case 21 . Motor casing 10 and inverter case 21 are formed in a cylindrical shape coaxial with central axis O of drive shaft 5 . Motor casing 10 and inverter case 21 are arranged in series in the axial direction of drive shaft 5 . Therefore, the electric motor assembly 1 has a compact structure. A cooling fan 30 is fixed to the end of the drive shaft 5 (that is, the non-load side of the drive shaft 5). Cooling fan 30 is arranged outside inverter case 21 and is adjacent to inverter case 21 .

A motor 8 that is a heat source is arranged inside the motor casing 10 . The motor 8 includes a rotor 6 fixed to the drive shaft 5 and a stator 7 surrounding the rotor 6 and receiving power from the outside (not shown) to form a rotating magnetic field. The stator 7 includes a stator core and coils wound around the stator core. The drive shaft 5 is fixed to the rotor 6 and rotates together with the rotor 6 by the rotating magnetic field described above.

In FIG. 1, the motor 8 is depicted schematically. The motor 8 is, for example, a permanent magnet type motor using a permanent magnet for the rotor. However, the motor 8 is not limited to a permanent magnet type motor, and may be various types of motors such as an induction motor and an SR motor.

The motor casing 10 includes a motor frame 11 to which the stator 7 is fixed, an end cover 12 which closes one open end of the motor frame 11 and has a through hole 12a through which the drive shaft 5 passes, and the motor frame 11. and a motor side plate 13 (inverter case side bracket) that closes the other open end of the motor side plate 13 and has a through hole 13a through which the drive shaft 5 passes.

The end cover 12 and the motor side plate 13 face each other across the motor 8 in the axial direction. The drive shaft 5 is rotatably supported by a bearing 14 supported by the bearing support portion 12b of the end cover 12. As shown in FIG. Further, the drive shaft 5 is rotatably supported by a bearing 15 supported by the bearing support portion 13b of the motor side plate 13. As shown in FIG.

Inverter case 21 surrounds inverter 20 . The inverter case 21 includes an inverter frame 22 arranged around the inverter 20 , a cooling fan side cover member 23 (cooling fan side bracket) that closes one open end of the inverter frame 22 , and the other open end of the inverter frame 22 . and a motor casing side cover member 24 (motor casing side bracket) that closes.

The cooling fan side cover member 23 is adjacent to the cooling fan 30 and has a through hole 23a through which the drive shaft 5 passes. The motor casing side cover member 24 is adjacent to the motor side plate 13 of the motor casing 10 and has a through hole 24a through which the drive shaft 5 passes. The through holes 23 a and 24 a are axially connected via a cylindrical member 25 . The tubular member 25 surrounds the drive shaft 5 .

The inverter frame 22 is connected to the cooling fan side cover member 23 and the motor casing side cover member 24 while being sandwiched in the axial direction. The connection structure between the inverter frame 22 and the cooling fan side cover member 23 and the connection structure between the inverter frame 22 and the motor casing side cover member 24 are fitting structures, but the connection structure is not particularly limited.

A plurality of radiating fins 22a extending radially outward are formed on the outer surface of the inverter frame 22 . The plurality of heat radiating fins 22 a extends in the axial direction of the drive shaft 5 . Inverter case 21 (more specifically, inverter frame 22) is cooled when air sent by rotation of cooling fan 30 comes into contact with heat radiating fins 22a. Inverter 20 is cooled via inverter case 21 .

A plurality of heat radiation fins 11a extending radially outward are formed on the outer surface of the motor frame 11 . The plurality of heat radiating fins 11 a extends in the axial direction of the drive shaft 5 . The motor casing 10 (more specifically, the motor frame 11) is cooled by the air sent by the cooling fan 30 coming into contact with the heat radiation fins 11a. The motor 8 is then cooled via the motor casing 10 .

The electric motor assembly 1 has a fan cover 26 that covers the cooling fan 30 . The fan cover 26 is arranged so as to cover the cooling fan side cover member 23 and is fixed to the cooling fan side cover member 23 . The fan cover 26 has a suction port 26a facing the cooling fan 30 in the axial direction. Further, the fan cover 26 has a discharge port 26b that discharges air along the outer surface of the inverter frame 22. As shown in FIG.

A plurality of heat radiation fins 23 b are formed on the outer surface of the cooling fan side cover member 23 . The radiating fins 23 b stand axially from the cooling fan side cover member 23 toward the cooling fan 30 . 2, the radiation fins 23b radially extend in the radial direction around the drive shaft 5. As shown in FIG.

Returning to FIG. 1 , the inverter 20 is arranged inside the inverter case 21 . The inverter 20 includes a heating element 41 including elements such as switching elements and capacitors, and a substrate 42 on which the heating element 41 is mounted. The board 42 is fixed to the inner surface of the cooling fan side cover member 23 . The inner surface of the cooling fan side cover member 23 has a saucer shape on which the substrate 42 is placed. With such a structure, the cooling fan side cover member 23 can be filled with a resin for heat dissipation and surface protection of the substrate 42 .

Each of motor 8 and inverter 20 is a heat source. Therefore, considering the heat dissipation of the motor 8 and the inverter 20, it is preferable to use aluminum or iron, which have high thermal conductivity, as the material of the motor frame 11 and the inverter frame 22. FIG.

FIG. 3 is an enlarged cross-sectional view of the electric motor assembly 1 near the cooling fan 30 according to one embodiment. FIG. 4 is a perspective view of the front side of the cooling fan 30 according to one embodiment. FIG. 5 is a perspective view of the back side of the cooling fan 30 according to one embodiment. 6 is a cross-sectional view taken along line AA shown in FIG. 4. FIG.
As shown in these figures, the cooling fan 30 has a hub 31, blades 32, a lower plate 33 (rectifying guide), and rear blades . In this embodiment, the hub 31, the blades 32, the lower plate 33, and the rear blades 34 are integrally formed. This integral molding is not limited to resin molding, and metal (such as casting) may be used.

As shown in FIG. 3, the hub 31 is cylindrical and has an insertion hole 31a into which the end of the drive shaft 5 is inserted. A peripheral surface 31 b (outer surface) of the hub 31 is provided with blades 32 (front blades). As shown in FIG. 4, a plurality of blades 32 are provided at intervals in the circumferential direction. The plurality of blades 32 radially extend radially outward from the peripheral surface 31 b of the hub 31 .

As shown in FIG. 3 , the lower portion of the blade 32 (the end on the inverter case 21 side in the axial direction) is supported by the lower plate 33 . The lower plate 33 is a conical plate provided on the peripheral surface 31 b of the hub 31 . The lower plate 33 has a shape whose diameter gradually increases from the middle portion of the peripheral surface 31b of the hub 31 in the axial direction toward the inverter case 21 side. The lower plate 33 forms a smooth conical surface without through holes or notches. A surface 33a of the lower plate 33 (the conical surface on the side opposite to the inverter case 21) is connected to the lower portions of the blades 32 and supports the blades 32. As shown in FIG.

A back blade 34 is provided on the back side of the lower plate 33 . As shown in FIG. 5, a plurality of back blades 34 are provided at intervals in the circumferential direction. The circumferential pitch of these rear blades 34 is the same as that of the blades 32 on the front surface 33a side described above, but it does not have to be the same. Also, the number of back blades 34 may not be the same as the number of blades 32 on the front surface 33a side.

As shown in FIG. 6, the back blade 34 extends radially to the outer peripheral end 33c of the lower plate 33. As shown in FIG. On the other hand, the blades 32 do not radially extend to the outer peripheral edge 33c of the lower plate 33. As shown in FIG. Further, the back blade 34 is provided radially apart from the peripheral surface 31b of the hub 31 . That is, a gap S is formed between the back blade 34 and the hub 31 in the radial direction. It is preferable that the gap S has a dimension that takes into consideration the part that needs to be cooled and the rotational resistance of the cooling fan 30 .

Further, the back blade 34 protrudes axially from the space 33B on the back side of the lower plate 33 . The space 33B on the back side of the lower plate 33 refers to a conical space surrounded by the back surface 33b of the lower plate 33 . That is, the back blade 34 extends axially from the back surface 33b of the lower plate 33 and protrudes toward the inverter case 21 (see FIG. 3) beyond the space 33B (or the outer peripheral end 33c) on the back side of the lower plate 33. As shown in FIG. 3, the back blade 34 rotates at a position axially overlapping with at least a portion of the heat generating element 41 of the inverter 20 .

According to the cooling fan 30 configured as described above, when the drive shaft 5 rotates, the blades 32 provided on the hub 31 axially suck air from the suction port 26a of the fan cover 26 shown in FIG. The centrifugal force received from the vanes 32 causes the fluid to be discharged in the radial direction. The air discharged in the radial direction is radially guided to the outer surface of the inverter case 21 by the inner surface of the fan cover 26 and the surface 33a (conical surface) of the lower plate 33, and is discharged from the outlet 26b of the fan cover 26 to the inverter frame 22. is discharged axially along the radiating fins 22a.

A back blade 34 is provided on the back side of the lower plate 33 . The back blade 34 rotates together with the blade 32 and diffuses the air on the back side of the lower plate 33. - 特許庁As a result, heat is not trapped between the lower plate 33 and the inverter case 21 . Therefore, it is possible to prevent the heat dissipation of inverter 20 from deteriorating. Further, the rotation of the back blade 34 imparts a centrifugal force to the air on the back side of the lower plate 33, and the air can be guided in the radial direction through the gaps between the radially extending radiation fins 23b.

As described above, according to the present embodiment described above, the hub 31 attached to the drive shaft 5 of the motor 8, the blades 32 provided on the peripheral surface 31b of the hub 31, and the blades 32 provided on the peripheral surface 31b of the hub 31 , a conical lower plate 33 for supporting the blades 32 on the surface 33a, and a rear blade 34 provided on the back side of the lower plate 33, the lower plate 33 of the cooling fan 30 is The air on the back side can be diffused to improve heat dissipation.

In addition, in the present embodiment, as shown in FIG. 6, the back blade 34 is provided radially apart from the peripheral surface 31b of the hub 31 . According to this configuration, it is possible to suppress an increase in the rotation resistance of the cooling fan 30 due to a portion of the rear blade 34 near the peripheral surface 31b of the hub 31 where the peripheral speed is slow and does not contribute much to the diffusion of the air. This allows the cooling fan 30 to rotate with a low load.

Further, in the present embodiment, the rear blade 34 extends radially to the outer peripheral end 33c of the lower plate 33. As shown in FIG. According to this configuration, the air diffused on the back side of the lower plate 33 can be easily pushed out radially outward from the outer peripheral end 33 c of the lower plate 33 by the back blade 34 . Therefore, heat is less likely to be trapped between the lower plate 33 and the inverter case 21 .

Further, in this embodiment, the back blade 34 axially protrudes from the space 33B on the back side of the lower plate 33 . According to this configuration, more air flow can be formed on the back side of the lower plate 33 . Therefore, it becomes more difficult for heat to remain between the lower plate 33 and the inverter case 21 .

FIG. 7 is an analysis diagram showing the flow of air when the back blade 34 does not protrude from the space 33B on the back side of the lower plate 33 in the axial direction as a comparative example. FIG. 8 is an analysis diagram showing the flow of air when the back blade 34 protrudes axially from the space 33B on the back side of the lower plate 33 as an example. 7 and 8, the airflow is represented by the magnitude of the vector.
It can clearly be seen that in FIG. 7 there is less air flow behind the lower plate 33, whereas in FIG. 8 there is more air flow behind the lower plate 33 than in FIG. Thus, according to the above configuration, the effect of diffusing the air behind the lower plate 33 of the cooling fan 30 is improved.

Further, in this embodiment, the hub 31, the blades 32, the lower plate 33, and the rear blades 34 are integrally formed. As a result, the rigidity of each part of cooling fan 30 and the rigidity of the entire cooling fan 30 can be increased, and cooling fan 30 can be manufactured at low cost.

The electric motor assembly 1 of this embodiment includes a drive shaft 5, a motor 8 that rotates the drive shaft 5, a motor casing 10 in which the motor 8 is arranged, and an inverter 20 that controls the operation of the motor 8. , an inverter case 21 in which the inverter 20 is arranged and the drive shaft 5 penetrates; a cooling fan 30 arranged adjacent to the inverter case 21 and having a rear blade 34 fixed to the end of the drive shaft 5; , the air on the back side of the lower plate 33 of the cooling fan 30 can be diffused to improve heat dissipation.

Further, in the present embodiment, as shown in FIG. 3, the back blade 34 of the cooling fan 30 rotates at a position axially overlapping at least a part of the heat generating element 41 of the inverter 20, so that the heat of the heat generating element 41 is dissipated. , can be efficiently cooled through the heat radiation fins 23b.

While the preferred embodiments of the invention have been described and described, it is to be understood that they are illustrative of the invention and should not be considered limiting. Additions, omissions, substitutions, and other modifications may be made without departing from the scope of the invention. Accordingly, the invention should not be viewed as limited by the foregoing description, but rather by the claims appended hereto.

For example, as shown in FIG. 9, the back blade 34 may be uneven. Protrusions 34a and recesses 34b are formed alternately in the radial direction on the plate surface of the back blade 34 shown in FIG. 9 facing the rotational direction. When the back blade 34 rotates, stagnation and swirl are generated in the concave portion 34b, making it easier to diffuse the air. Such irregularities may be provided on the pressure surface side of the rear blade 34, or may be provided on the suction surface side of the rear blade 34 to form a vortex rearward in the rotational direction like a Karman vortex.

Further, for example, in the above-described embodiment, an electric motor was exemplified as the rotating machine to which the cooling fan 30 is attached, but it may be a generator.

1 electric motor assembly 5 drive shaft 8 motor (rotating machine)
10 Motor casing 20 Inverter 21 Inverter case 30 Cooling fan 31 Hub 31b Peripheral surface 32 Blade 33 Lower plate 33a Surface (conical surface)
33B Space 33c Outer edge 34 Back blade 41 Heating element

Claims (5)

a hub attached to the drive shaft of the rotating machine;
vanes provided on the peripheral surface of the hub;
a conical lower plate provided on the peripheral surface of the hub and supporting the blades on a conical surface; and a back blade provided on the back side of the lower plate ,
The back blade protrudes in the axial direction from a space on the back side of the lower plate, has a radially inner edge extending vertically along the axial direction, and extends from the radially inner edge to the outer periphery of the lower plate. A cooling fan , characterized in that it extends radially to the ends . 2. The cooling fan according to claim 1, wherein the back blade is radially spaced from the peripheral surface of the hub. 3. The cooling fan according to claim 1, wherein said hub, said blades, said lower plate, and said rear blades are integrally molded. a drive shaft;
a motor that rotates the drive shaft;
a motor casing in which the motor is arranged;
an inverter that controls the operation of the motor;
an inverter case in which the inverter is arranged and through which the drive shaft passes;
a cooling fan disposed adjacent to the inverter case and fixed to an end of the drive shaft, the motor assembly comprising:
A motor assembly comprising the cooling fan according to any one of claims 1 to 3 as the cooling fan. 5. The electric motor assembly according to claim 4 , wherein the back blade of the cooling fan rotates in a position overlapping at least a part of the heat generating element of the inverter in the axial direction.

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