Electric fan and electric vertical take-off and landing aircraft

Abstract

In an electric fan and an electric vertical take-off and landing aircraft, the present invention is provided with: a drive motor in which an output shaft is at one end in the axial direction, a cooling air intake port is at the other end in the axial direction, and a cooling air discharge port is provided at the outer peripheral part in the radial direction; a rotor blade which is attached to the output shaft; a strut having a hollow shape which is connected via a support member to the other end of the drive motor and which is disposed along the radial direction of the drive motor; and a communication part which communicates the inside of the strut with the air intake port.

Description

Electric fan and electric vertical take-off and landing aircraft

[0001] The present disclosure relates to electric fans and electric vertical take-off and landing aircraft.

[0002] In recent years, development of electric vertical take-off and landing aircraft capable of taking off and landing vertically has been progressing as a type of flying car. Some electric vertical take-off and landing aircraft, for example, are equipped with multiple electric fans on the airframe, and the angle of the electric fans can be adjusted relative to the airframe. That is, some electric vertical take-off and landing aircraft have their electric fans facing up and down during take-off and landing, and facing forward and backward during flight. As the electric fans for electric vertical take-off and landing aircraft, peripheral drive fans with drives located on the periphery are used. An example of an electric fan for such an electric vertical take-off and landing aircraft is described in Patent Document 1 below.

[0003] International Publication No. 2019 / 191240

[0004] An electric fan has a motor that drives rotor blades to rotate. The coils and magnets inside the motor generate heat, so they must be cooled. Some motor cooling structures use air drawn in from the front of the fan to cool the interior and then discharge the cooled air from the rear or side. However, a structure that draws air in from the front of the fan can result in foreign matter, such as dust, being drawn into the interior. Therefore, a possible motor cooling structure is one that draws air in from the rear of the fan to cool the interior and then discharges the cooled air from the side. However, when drawing air in from the rear of the fan, the pressure at the air intake is the same as or lower than the pressure at the air outlet, making it difficult for air to flow through the interior of the motor and making it difficult to properly cool the coils and magnets.

[0005] The present disclosure is devised to solve the above-mentioned problems, and aims to provide an electric fan and an electric vertical take-off and landing aircraft that improve the cooling performance of a motor.

[0006] In order to achieve the above-mentioned object, the electric fan of the present disclosure comprises a drive motor having an output shaft at one axial end, a cooling air intake port at the other axial end, and a cooling air exhaust port on the radial outer periphery, rotor blades attached to the output shaft, a hollow strut connected to the other end of the drive motor via a support member and arranged along the radial direction of the drive motor, and a communication part that communicates between the inside of the strut and the air intake port.

[0007] The electric vertical take-off and landing aircraft of the present disclosure also includes the electric fan.

[0008] The electric fan and electric vertical take-off and landing aircraft of the present disclosure can improve the cooling performance of the motor.

[0009] Fig. 1 is a cross-sectional view of an electric fan according to a first embodiment, Fig. 2 is a cross-sectional view of a motor constituting the electric fan, and Fig. 3 is a cross-sectional view of an electric fan according to a second embodiment.

[0010] Preferred embodiments of the present disclosure will be described in detail below with reference to the drawings. Note that the present disclosure is not limited to these embodiments, and when there are multiple embodiments, the present disclosure also includes configurations that combine the embodiments. Furthermore, the components in the embodiments include those that can be easily imagined by a person skilled in the art, those that are substantially identical, and those that are within the so-called equivalent range.

[0011] [First embodiment] <Electric fan> Fig. 1 is a cross-sectional view showing an electric fan according to a first embodiment. Note that Fig. 1 is a half cross-sectional view in which only the upper radial portion is broken away, but the lower radial portion has the same configuration.

[0012] Electric fans are used as a drive source for electric vertical take-off and landing aircraft. Electric vertical take-off and landing aircraft can take off and land vertically. Some electric vertical take-off and landing aircraft are equipped with multiple electric fans on the airframe, and the angle of the electric fans can be adjusted relative to the airframe. Some electric vertical take-off and landing aircraft are equipped with separate fans for vertical take-off and landing and horizontal movement, in which case the electric fans may be fixed to the airframe. However, the application of electric fans is not limited to the drive source of electric vertical take-off and landing aircraft.

[0013] As shown in FIG. 1 , the electric fan 10 includes a drive motor 11 , a rotor blade (fan) 12 , a strut 13 , and a communication portion 14 .

[0014] The drive motor 11 has an output shaft 21 whose center of rotation is along the axis O. The output shaft 21 is located at one end of the drive motor 11 in the axis O direction. The one end side of the drive motor 11 (the left side in Figure 1) is the forward direction. The drive motor 11 is provided with a cooling air intake port 22 at the other end in the axis O direction, and a cooling air exhaust port 23 on the outer periphery in the radial direction perpendicular to the axis O direction.

[0015] The drive motor 11 has rotor blades 12 attached to the output shaft 21. The rotor blades 12 have a support portion 31, an attachment portion 32, and multiple blade bodies 33. The support portion 31 is cylindrical and has an outer diameter substantially the same as that of the drive motor 11. The attachment portion 32 is provided on the inner periphery of the support portion 31. The attachment portion 32 extends from the inner periphery of the support portion 31 toward the axis O and is connected to the output shaft 21. The multiple blade bodies 33 are provided on the outer periphery of the support portion 31. The base ends of the multiple blade bodies 33 are fixed to the outer periphery of the support portion 31 and the tip ends extend radially outward. The multiple blade bodies 33 are arranged at intervals (preferably equal intervals) around the circumferential direction of the support portion 31. A hemispherical cover 34 is attached to one end of the support portion 31 of the rotor blade 12. However, the cover 34 is not limited to a hemispherical shape, and may have other shapes, such as a conical shape.

[0016] The strut 13 is connected to the other end of the drive motor 11 via a support member 41. The strut 13 is arranged along the radial direction of the drive motor 11. The strut 13 is arranged along a direction intersecting the axial line O. The strut 13 has a cylindrical tube shape (hollow shape) and is longer than the outer diameter of the drive motor 11. The support member 41 has a hollow box-like cylindrical shape and is fixed to the other end of the drive motor 11. The strut 13 is arranged to radially penetrate the support member 41 and is fixed to the support member 41. An air intake port 42 is provided at the longitudinal end (end face) of the strut 13. Note that the position of the air intake port 42 is not limited to the longitudinal end face and may be provided, for example, on the side surface of the longitudinal end.

[0017] The communication portion 14 communicates between the interior of the strut 13 and the cooling air intake 22 of the drive motor 11. The communication portion 14 has a communication opening 43. However, the communication portion 14 is not limited to the communication opening 43 and may be a pipe that directly communicates between the interior of the strut 13 and the cooling air intake 22 of the drive motor 11. The communication opening 43 opens at a position on the strut 13 opposite the cooling air intake 22. An opening 44 is provided in the support member 41 at a position sandwiched between the cooling air intake 22 and the communication opening 43.

[0018] In the electric fan 10, an external duct 51 is disposed outside the rotor blades 12. The external duct 51 has a cylindrical (ring-like) shape and supports the tips of the plurality of blade bodies 33 so that they can move freely in the circumferential direction. The external duct 51 is also supported by struts 13 that pass through it. That is, the other axial end of the external duct 51 is supported by the struts 13, and one axial end of the external duct 51 supports the tips of the plurality of rotor blades 12.

[0019] The electric fan 10 is provided with a duct 52. The duct 52 covers the cooling air intake 22 of the drive motor 11 and the communication opening 43 that constitutes the communication part 14 from the outside. The duct 52 is fixed to the other end of the drive motor 11 and has a shape that tapers toward the other end.

[0020] <Drive Motor> FIG. 2 is a cross-sectional view of a motor that constitutes the electric fan.

[0021] The drive motor 11 includes a housing 24, a rotor 25, a coil 26, and a permanent magnet 27. The rotor 25 is rotatably supported relative to the housing 24 by bearings (not shown), the coil 26 is fixed to the housing 24, and the permanent magnet 27 is fixed to the rotor 25. The coil 26 functions as a stator-side magnet (electromagnet), and the permanent magnet 27 functions as a rotor-side magnet. The coil 26 is arranged in a ring shape inside the housing 24, and the permanent magnet 27 is arranged in a ring shape on the inner circumferential surface of the rotor 25. The permanent magnet 27 is arranged so that positive and negative poles alternate in the circumferential direction. The coil 26 and the permanent magnet 27 are arranged facing each other in the radial direction. Fins 28 are fixed to the inner circumferential portion of the coil 26, and a plurality of blades 29 are fixed to the rotor 25 at intervals in the circumferential direction.

[0022] Therefore, when current is applied to the coil 26, a magnetic field is generated between the coil 26 and the permanent magnet 27, and rotational power is applied to the permanent magnet 27. The rotational power of the permanent magnet 27 is then transmitted to the rotor 25, causing the rotor 25 to rotate, and the output shaft 21 connected to the rotor 25 to rotate. When the rotor 25 rotates, a plurality of vanes 29 provided on the rotor 25 generate an air flow inside the drive motor 11.

[0023] The drive motor 11 is provided with a cooling air intake port 22 at the other end and a cooling air exhaust port 23 at the outer periphery. Air flows inside the drive motor 11 from the cooling air intake port 22 toward the cooling air exhaust port 23.

[0024] 1 and 2 , when the drive motor 11 is driven, the output shaft 21 is driven to rotate, thereby rotating the rotor blades 12 connected to the output shaft 21. At this time, the rotor 25 of the drive motor 11 rotates, and an internal air flow from the cooling air inlet 22 to the cooling air outlet 23 is generated by the blades 29 of the rotor 25. That is, the drive motor 11 takes in external air through the cooling air inlet 22, thereby cooling the coils 26 and permanent magnets 27 arranged inside with the air. The air that has cooled the coils 26 and permanent magnets 27 is then discharged to the outside through the cooling air outlet 23.

[0025] The cooling air intake 22 of the drive motor 11 communicates with the interior of the strut 13 through the communication part 14 (communication opening 43). The strut 13 has an air intake 42 at one end in the longitudinal direction. That is, the air flow generated by driving the drive motor 11 acts as a negative pressure on the cooling air intake 22. The negative pressure at the cooling air intake 22 acts on the air intake 42 through the communication part 14 (communication opening 43). Therefore, air is drawn in through the air intake 42 of the strut 13, and the drawn in air passes through the communication part 14 (communication opening 43) and the cooling air intake 22 and is introduced into the interior of the drive motor 11.

[0026] At this time, because the air intake 42 of the strut 13 is open to the atmosphere, the pressure P1 at the cooling air intake 22 is substantially equal to atmospheric pressure. On the other hand, the pressure P2 at the cooling air discharge port 23 is lower than atmospheric pressure because it is located aft of the rotor blade 12, and the pressure difference between the two becomes large. As a result, the drive motor 11 can easily take in air from the cooling air intake 22 and easily discharge it from the cooling air discharge port 23, allowing an appropriate amount of cooling air to flow inside.

[0027] Second Embodiment Fig. 3 is a cross-sectional view showing an electric fan according to a second embodiment. Note that members having the same functions as those in the first embodiment described above are given the same reference numerals and detailed descriptions thereof will be omitted.

[0028] As shown in FIG. 3, the electric fan 10A includes a drive motor 11, a rotor blade (propeller) 12A, a strut 13, and a communication portion 14.

[0029] The drive motor 11 has an output shaft 21. The drive motor 11 is provided with a cooling air intake port 22 at the other end in the direction of the axis O, and a cooling air discharge port 23 at the outer periphery in the radial direction perpendicular to the direction of the axis O. The drive motor 11 has rotor blades 12A attached to the output shaft 21. The rotor blades 12A have a base end fixed to the output shaft 21 and a tip end extending radially outward. The multiple rotor blades 12A are arranged at intervals (preferably equal intervals) in the circumferential direction.

[0030] The strut 13 is connected to the other end of the drive motor 11 via a support member 41. The strut 13 is arranged along the radial direction of the drive motor 11. The support member 41 has a hollow, box-like cylindrical shape and is fixed to the other end of the drive motor 11. The strut 13 is arranged to penetrate the support member 41 in the radial direction and is fixed to the support member 41. An air intake port 42 is provided at the longitudinal end (end face) of the strut 13.

[0031] The communication portion 14 communicates between the interior of the strut 13 and the cooling air intake 22 of the drive motor 11. The communication portion 14 has a communication opening 43. The communication opening 43 opens at a position on the strut 13 opposite the cooling air intake 22. The support member 41 has an opening 44 formed between the cooling air intake 22 and the communication opening 43.

[0032] The electric fan 10 is provided with a duct 52A. The duct 52A covers the cooling air intake 22 of the drive motor 11 and the communication opening 43 that constitutes the communication section 14 from the outside. The duct 52A is fixed to the other end of the drive motor 11.

[0033] When the drive motor 11 is driven, the output shaft 21 is driven to rotate, thereby rotating the rotor blades 12A connected to the output shaft 21. At this time, a flow is generated inside the drive motor 11 from the cooling air inlet 22 to the cooling air outlet 23. That is, the drive motor 11 takes in external air through the cooling air inlet 22, thereby cooling the coils 26 and permanent magnets 27 arranged inside with the air. Then, the air that has cooled the coils 26 and permanent magnets 27 is discharged to the outside through the cooling air outlet 23.

[0034] That is, air is drawn in through the air inlet 42 of the strut 13, and then passes through the communication portion 14 (communication opening 43) and the cooling air inlet 22 before being introduced into the interior of the drive motor 11. At this time, because the air inlet 42 of the strut 13 is open to the atmosphere, the pressure P1 at the cooling air inlet 22 is substantially equal to atmospheric pressure. On the other hand, because the pressure P2 at the cooling air outlet 23 is located aft of the rotor blade 12A, it is lower than atmospheric pressure, and the pressure difference between the two is large. As a result, the drive motor 11 can easily take in air through the cooling air inlet 22 and easily discharge it through the cooling air outlet 23, allowing an appropriate amount of cooling air to flow inside.

[0035] [Effects of this embodiment] The electric fan according to the first aspect comprises a drive motor 11 having an output shaft 21 at one axial end, a cooling air intake 22 at the other axial end, and a cooling air exhaust 23 on the radial outer periphery, rotor blades 12, 12A attached to the output shaft 21, a hollow strut 13 connected to the other end of the drive motor 11 via a support member 41 and arranged along the radial direction of the drive motor 11, and a communication section 14 connecting the interior of the strut 13 to the cooling air intake 22.

[0036] In the electric fan according to the first aspect, the cooling air intake 22 is connected to the atmospheric pressure area through the communication portion 14 and the strut 13, which makes it easier for atmospheric air to be drawn into the drive motor 11 from the tip of the strut 13 through the communication portion 14, facilitating air flow within the drive motor 11 and enabling the inside of the drive motor 11 to be appropriately cooled. As a result, the cooling performance of the drive motor 11 can be improved.

[0037] The electric fan according to the second aspect is the electric fan according to the first aspect, and further includes a communication opening 43 as the communication part 14 in the strut 13 at a position facing the cooling air intake 22. By using the communication opening 43 as the communication part 14, the structure can be simplified.

[0038] The electric fan according to the third aspect is the electric fan according to the first or second aspect, further comprising an air intake 42 provided at a longitudinal end of the strut 13. This allows atmospheric air to be appropriately drawn in through the air intake 42.

[0039] The electric fan according to the fourth aspect is the electric fan according to the third aspect, further comprising a duct 52 that externally covers the cooling air intake 22 and the communication opening 43. By externally covering the cooling air intake 22 and the communication opening 43 with the duct 52, the pressure at the cooling air intake 22 and the communication opening 43 can be maintained at atmospheric pressure.

[0040] The electric fan according to a fifth aspect is the electric fan according to any one of the first to fourth aspects, further comprising a ring-shaped external duct 51 that supports the tips of the rotor blades 12, 12A and the other end of the strut 13. This allows the rotor blades 12, 12A to be properly supported.

[0041] The electric vertical take-off and landing aircraft according to the sixth aspect includes the electric fan 10, 10A according to any one of the first to fifth aspects, thereby improving the cooling performance of the drive motor 11.

[0042] 10, 10A Electric fan 11 Drive motor 12, 12A Rotor blade 13 Strut 14 Communication portion 21 Output shaft 22 Cooling air intake port 23 Cooling air exhaust port 31 Support portion 32 Mounting portion 33 Blade body 34 Cover 41 Support member 42 Air intake port 43 Communication opening 44 Opening 51 External duct 52 Duct 24 Housing 25 Rotor 26 Coil 27 Permanent magnet 28 Fin 29 Blade

Claims

1. An electric fan comprising: a drive motor having an output shaft at one axial end, a cooling air intake at the other axial end, and a cooling air discharge port on the radial outer periphery; rotor blades attached to the output shaft; a hollow strut connected to the other end of the drive motor via a support member and arranged along the radial direction of the drive motor; and a communication part communicating the interior of the strut with the cooling air intake.

2. The electric fan according to claim 1, wherein the strut has a communication opening as the communication section at a position facing the cooling air intake.

3. The electric fan according to claim 2, wherein the strut has an air intake port at one end in the longitudinal direction.

4. The electric fan according to claim 2 or 3, further comprising a duct that covers the cooling air intake and the communication opening from the outside.

5. The electric fan according to claim 1, further comprising a ring-shaped external duct that supports the tips of the rotor blades and the other ends of the struts.

6. An electric vertical take-off and landing aircraft equipped with the electric fan according to claim 1.

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