electric aircraft

Abstract

To provide an electric aircraft which has a simple and lightweight structure, and improves lightning resistance reliability.SOLUTION: An electric aircraft includes a machine body, a plurality of structure skeleton members provided on the machine body, fan motors provided on each of the structure skeleton members, and tip electric field concentration parts provided on the ends of the structure skeleton members, wherein the impedances of the structure skeleton members are lower than the impedance of the fan motor, and accordingly when lightning strikes the electric aircraft, current flows in not the fan motor but the structure skeleton members. Thereby, damage to the fan motor by lightning strike can be avoided.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] The present disclosure relates to an electric aircraft.

Background Art

[0002] Electric aircraft equipped with electric fans (fan motors) have been variously put into practical use. The electric aircraft includes an airframe and a plurality of structural skeleton members provided on the airframe. By driving the fan motor, thrust is generated to realize the ascent, descent, and horizontal flight of the airframe.

[0003] By the way, with the increase in transportation demand, there has been an increasing demand to operate an electric aircraft under all weather conditions. In particular, attention has been focused on the technology to stably fly an electric aircraft even under weather conditions where lightning is expected. As a specific example of such technology, the one described in Patent Document 1 below is known. In the technology according to Patent Document 1 below, an arrester is provided for the fan motor so that the current during lightning strike does not flow to the motor side.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0005] However, when an arrester is provided for the fan motor as described above, there are problems that the occupied space of the arrester itself is required and it leads to an increase in weight. For this reason, there has been an increasing demand for a technology that can improve the reliability against lightning strikes under a simpler configuration.

[0006] The present disclosure has been made to solve the above problems, and an object thereof is to provide an electric aircraft having a simpler and lighter configuration and improved lightning resistance reliability. [Means for solving the problem]

[0007] To solve the above problems, the electric aircraft according to this disclosure comprises an airframe, a plurality of structural frame members provided on the airframe, fan motors provided on each of the structural frame members, and an end field concentration section provided at the end of the structural frame member, wherein the impedance of the structural frame member is lower than the impedance of the fan motor. The fan motor is further provided with a fan electric field concentration section, the fan electric field concentration section having a cylindrical portion that surrounds the fan motor from the outer circumference, and a plurality of electric field concentration section bodies extending outward from the cylindrical portion, the impedance of the fan electric field concentration section being lower than the impedance of the fan motor. [Effects of the Invention]

[0008] This disclosure provides an electric aircraft with a simpler and lighter configuration and improved lightning protection reliability. [Brief explanation of the drawing]

[0009] [Figure 1] This is a front view showing the configuration of an electric aircraft according to the first embodiment of this disclosure. [Figure 2] This is a plan view showing the configuration of an electric aircraft according to a second embodiment of the present disclosure. [Figure 3] This is an enlarged view of the main part of an electric aircraft according to the second embodiment of this disclosure. [Figure 4] This is an enlarged view of a key part showing a first modified example of an electric aircraft according to the second embodiment of this disclosure. [Figure 5] This is an enlarged view of a key part showing a second modified example of an electric aircraft according to the second embodiment of this disclosure. [Figure 6] This is an enlarged view of a key part showing a third modified example of an electric aircraft according to the second embodiment of this disclosure. [Figure 7] This is a perspective view showing the configuration of an electric aircraft according to a third embodiment of this disclosure. [Figure 8] This is a front view showing a modified example of an electric aircraft according to the third embodiment of this disclosure. [Figure 9] This is an enlarged view of the main part of an electric aircraft according to the fourth embodiment of this disclosure. [Modes for carrying out the invention]

[0010] <First Embodiment> (Configuration of an electric aircraft) Hereinafter, an electric aircraft 1 according to the first embodiment of this disclosure will be described with reference to Figure 1. As shown in Figure 1, the electric aircraft 1 comprises an airframe 10, a structural frame member 20, a fan motor 30, and a front electric field concentration section 40.

[0011] The aircraft body 10 is container-shaped for carrying fuel, batteries, cargo, etc. A pair of structural frame members 20 are provided on the upper surface of the aircraft body 10 when it is placed on the ground. The structural frame members 20 intersect each other on the upper surface of the aircraft body 10, and extend radially from the aircraft body 10 along the horizontal plane. However, the structural frame members 20 do not necessarily have to intersect, and their shape and form can be appropriately changed according to the design and specifications. Fan motors 30 are provided at intermediate positions along the extension of each structural frame member 20. In the example in Figure 1, two fan motors 30 are provided on each structural frame member 20, but the number of fan motors 30 is just an example and can be appropriately changed according to the design and specifications.

[0012] The fan motor 30 includes a propeller 31 that can rotate around axis O, and an electric motor (not shown). By supplying current to the electric motor, the propeller 31 is driven to rotate around axis O. Thrust is generated when the propeller 31 pressurizes and pumps the surrounding air in the direction of axis O. In the example in Figure 1, the direction of axis O of the propeller 31 is the vertical direction, but it is also possible to make the attitude of the propeller 31 variable. Furthermore, it is possible to have both a fan motor 30 for thrust that faces horizontally and a fan motor 30 for ascent and descent that faces vertically.

[0013] At the tip of the structural framework member 20, tip electric field concentration portions 40 are provided respectively. The tip electric field concentration portion 40 is a lightning receiving portion for concentrating and receiving a lightning strike current when encountering a lightning strike in the air. The tip electric field concentration portion 40 protrudes in the vertical direction from the surface of the structural framework member 20. The tip of the tip electric field concentration portion 40 has a sharp shape. Note that the shape of the tip electric field concentration portion 40 is an example, and it is also possible to use a wire-shaped member as the tip electric field concentration portion 40.

[0014] The impedances of the structural framework member 20 and the tip electric field concentration portion 40 are set lower than the impedance of the fan motor 30. It is desirable that such impedance adjustment be performed by appropriately selecting the types of materials forming the structural framework member 20 and the tip electric field concentration portion 40. Specifically, it is conceivable to form the structural framework member 20 and the tip electric field concentration portion 40 with aluminum. Also, in addition to this, it is also possible to adopt a configuration in which a copper mesh is attached to the surface of the structural framework member 20 or a diverting strip is attached. Furthermore, it is also possible to provide an electric circuit element such as a capacitor for receiving a lightning strike current at an intermediate position of the extension of the structural framework member 20, and function as a lightning receiving portion by lowering the discharge start voltage below the surroundings.

[0015] Furthermore, in the case of the front view shown in FIG. 1, the fan motor 30 and the aircraft body 1 are within the range of the protection angle θ formed by the tip electric field concentration portion 40. In this case, the protection angle θ is desirably within a range of 60° centered on the tip electric field concentration portion 40 as an example.

[0016] (Function and effect) Here, with the increasing transportation demand in recent years, there is an increasing demand to operate the electric aircraft 1 under all weather conditions. In particular, attention has been focused on the technology to stably fly the electric aircraft 1 even under weather conditions where lightning is expected. As a specific example of such technology, conventionally, an example in which an arrester is provided in the fan motor 30 so that the current during a lightning strike does not flow to the motor side has been put into practical use.

[0017] However, when an arrester is provided in the fan motor 30 as described above, there are problems such as the need for the occupied space of the arrester itself and an increase in weight. For this reason, there has been an increasing demand for a technology that can improve the reliability against lightning strikes under a simpler configuration. Therefore, the electric aircraft 1 according to the present embodiment adopts each of the above-described configurations.

[0018] When lightning strikes occur during the operation of the electric aircraft 1, the lightning strikes concentrate on at least one tip electric field concentration part 40. Thereafter, the current due to the lightning strike flows through the structural skeleton member 20 having a lower impedance than the fan motor 30 and is discharged into the air from the other tip electric field concentration part 40. That is, at this time, it is possible to suppress the lightning strike current from flowing into the fan motor 30 having a higher impedance than the structural skeleton member 20. Thereby, the possibility that the fan motor 30 is damaged by the high voltage of the lightning strike current can be greatly reduced. In particular, since the tip electric field concentration part 40 is provided at the tip of the structural skeleton member 20 protruding radially from the aircraft body 10, the lightning strike location can be arbitrarily controlled. Therefore, even under weather conditions where lightning is expected, the electric aircraft 1 can be flown stably and smoothly.

[0019] Furthermore, since the path through which the lightning strike current flows can be limited as described above only by making the impedances of the fan motor 30 and the structural skeleton member 20 different, for example, compared to a configuration in which an arrester is attached to the fan motor 30, an increase in the number of parts can be suppressed. Thereby, an increase in the weight of the electric aircraft 1 can be avoided. Also, by reducing the number of parts, it is possible to greatly reduce the manufacturing cost and the maintenance cost.

[0020] The first embodiment of this disclosure has been described above. It is possible to make various changes and modifications to the above configuration without departing from the gist of this disclosure. For example, in the first embodiment, the tip electric field concentration section 40 is fixed to the tip of the structural frame member 20. However, in order to ensure flight performance, it is also possible to configure the tip electric field concentration section 40 to be housed and deployed inside the structural frame member 20 under conditions where there is no risk of lightning strikes. In this case, a decrease in the aerodynamic performance of the electric aircraft 1 can be avoided, and an increase in flight range and improvement in fuel efficiency can be expected.

[0021] <Second Embodiment> Next, a second embodiment of the present disclosure will be described with reference to Figures 2 and 3. Components similar to those in the first embodiment are denoted by the same reference numerals, and detailed descriptions are omitted. As shown in Figure 2, in this embodiment, in addition to the configuration described in the first embodiment, the fan motor 30 itself is provided with a fan electric field concentration section 50.

[0022] The fan electric field concentration section 50 has a cylindrical section 51 and a plurality of electric field concentration section bodies 52. The cylindrical section 51 is cylindrical with axis O as its center and surrounds the fan motor 30 from the outer circumference. Note that the cylindrical section 51 does not necessarily have to be cylindrical, and may be rectangular or polygonal depending on the design and specifications. The electric field concentration section bodies 52 extend outward from the outer surface of the cylindrical section 51. More specifically, as shown in Figure 3, the electric field concentration section bodies 52 protrude from the end face of the cylindrical section 51 facing the axis O direction toward both sides in the direction of axis O. The electric field concentration section bodies 52 may be cylindrical or prismatic when viewed from the direction of axis O. The tip of the electric field concentration section body 52 can also be sharp. In addition, a plurality of electric field concentration section bodies 52 are provided at equal intervals in the circumferential direction of axis O (for example, four on each side).

[0023] The cylindrical portion 51 and the electric field concentration unit body 52, configured as described above, are made of a material with a lower impedance than the fan motor 30. In other words, when lightning strikes the electric field concentration unit body 52, it is possible to suppress the flow of lightning current into the fan motor 30 itself. After passing through the cylindrical portion 51, the current is discharged into the air from the other electric field concentration unit bodies 52 other than the one that was struck by lightning.

[0024] (Effects and Benefits) According to the above configuration, a fan electric field concentration section 50 is provided on the fan motor 30. As a result, if lightning strikes near the fan motor 30, the current flows not through the fan motor 30 itself, which has a relatively high impedance, but through the fan electric field concentration section 50, which has a relatively low impedance. More specifically, for example, if lightning strikes one electric field concentration section body 52, the lightning strike current flows from that electric field concentration section body 52 through the cylindrical section 51 to the other electric field concentration section body 52. ​​The current is then discharged into the air. In other words, the lightning strike current does not flow through the fan motor 30. This makes it possible to avoid damage to the fan motor 30 caused by the high voltage and large current of the lightning strike. Therefore, it becomes possible to fly the electric aircraft 1 more stably and smoothly even under weather conditions where lightning is expected.

[0025] The second embodiment of the present disclosure has been described above. It is possible to make various changes and modifications to the above configuration without departing from the gist of the present disclosure. For example, in the second embodiment, an example was described in which the electric field concentration body 52 extends in the direction of axis O. However, the direction in which the electric field concentration body 52 extends is not limited to this. As shown in Figure 4 as a first modified example, the electric field concentration body 52 may extend radially with respect to axis O. In this case, it is desirable that the multiple electric field concentration body 52 be arranged with spacing in the circumferential direction.

[0026] Furthermore, as shown in Figure 5, as a second modification, the electric field concentrating section body 52 may extend radially outward as it moves away from the cylindrical section 51. In other words, the electric field concentrating section body 52 extends in a direction inclined with respect to the axis O. In this case, the airflow path of the propeller 31 is not obstructed by the electric field concentrating section body 52, making it possible to fully utilize the thrust from the fan motor 30. As a result, the electric aircraft 1 can be operated even more efficiently.

[0027] In addition, as a third modification, as shown in Figure 6, the electric field concentration section body 52 can also be formed from a wire-like member. In this case, while ensuring lightning protection performance, it is possible to minimize the reduction in aerodynamic performance caused by the electric field concentration section body 52 compared to the above configurations. This makes it possible to fly the electric aircraft 1 more efficiently. Furthermore, in this case, it is also possible to make the electric field concentration section body 52 flexible. This allows the electric field concentration section body 52 to bend slightly due to the dynamic pressure during flight, further reducing the reduction in aerodynamic performance.

[0028] <Third Embodiment> Next, a third embodiment of the present disclosure will be described with reference to Figure 7. Components similar to those in the above embodiments are denoted by the same reference numerals, and detailed descriptions are omitted. As shown in Figure 7, in this embodiment, similar to the second modification of the second embodiment, the electric field concentrating section bodies 52 extend in directions inclined with respect to the axis O. Furthermore, the tips of these electric field concentrating section bodies 52 are connected by a wire member 53. More specifically, the wire member 53 forms an annular shape centered on the axis O. The diameter of the annular shape formed by the wire member 53 is larger than the diameter of the cylindrical section 51 and the propeller 31. A pair of such wire members 53 are provided, one on each side in the direction of the axis O. It is desirable that the wire member 53, like the fan electric field concentrating section 50, be made of a material with a lower impedance than the fan motor 30. In this case, the protection angle θ provided by the electric field concentrating section body 52 is preferably about 25°.

[0029] (Effects and Benefits) According to the above configuration, the ends of the electric field concentration unit bodies 52 are connected by wire members 53. This allows lightning strikes to be received over a wider area, not only by the electric field concentration unit bodies 52 but also by the entire length of the wire members 53. In other words, the wire members 53 themselves function as lightning receiving units. For example, if a lightning strike occurs on a wire member 53, current flows from that wire member 53 through the electric field concentration unit body 52 to the cylindrical section 51. The current then discharges from the cylindrical section 51 through another electric field concentration unit body 52 to the air from the other wire member 53. Therefore, the possibility of high voltage and large current flowing into the fan motor 30 due to a lightning strike is reduced. As a result, the risk of damage to the fan motor 30 due to lightning current can be greatly reduced.

[0030] Furthermore, with the above configuration, the wire member 53 forms an annular shape centered on the axis O of the propeller 31. This allows the wire member 53 to absorb lightning strikes over the entire circumferential area of ​​the axis O. Also, since the diameter of the annular shape formed by the wire member 53 is larger than the diameters of the propeller 31 and the cylindrical part 51, the wire member 53 does not obstruct the airflow path of the propeller 31. Therefore, the thrust of the propeller 31 can be fully utilized. Consequently, the electric aircraft 1 can be flown more efficiently and smoothly.

[0031] The third embodiment of this disclosure has been described above. It is possible to make various changes and modifications to the above configuration without departing from the gist of this disclosure. For example, as shown in Figure 8 as a modified example, the electric field concentration unit body 52 may have a plurality of circumferential members 61 and a plurality of axial members 62, and a part of the wire member 53 may connect the tips of these circumferential members 61 and the tips of the axial members 62. Specifically, the circumferential members 61 protrude radially from the outer circumferential surface of the cylindrical portion 51 and are provided in a plurality at intervals in the circumferential direction. The axial members 62 extend in a direction inclined with respect to the axis O, with an axial component in the direction of the axis O, similar to the third embodiment. A part of the wire member 53 forms an annular shape connecting the tips of the plurality of axial members 62, similar to the third embodiment. Another part of the wire member 53 connects the tips of the circumferential members 61 and the tips of the axial members 62.

[0032] According to the above configuration, the tip of the circumferential member 61 and the tip of the axial member 62 are connected by a portion of the wire member 53. This increases the area protected by the wire member 53, making it possible to withstand lightning strikes over a wider area. As a result, the fan motor 30 is protected from the load of lightning strike currents, and the electric aircraft 1 can fly more efficiently and stably.

[0033] <Fourth Embodiment> Next, a fourth embodiment of the present disclosure will be described with reference to Figure 9. Components similar to those in the above embodiments are denoted by the same reference numerals, and detailed descriptions are omitted. As shown in Figure 9, in the electric aircraft 1 according to this embodiment, the fan electric field concentration unit 50 further includes a sheath unit 70 in addition to the cylindrical unit 51 and the electric field concentration unit body 52. ​​The sheath unit 70 protrudes from the cylindrical unit 51 in various directions, as described in the above embodiments. The electric field concentration unit body 52 is movable back and forth between a state where it is housed inside the sheath unit 70 and a state where it is deployed and protruding to the outside. The electric field concentration unit body 52 moves back and forth in this manner by an actuator (not shown).

[0034] (Effects and Benefits) According to the above configuration, when lightning strikes are expected, the electric field concentration unit body 52 can be deployed to preferentially concentrate the lightning strike on the electric field concentration unit body 52. ​​On the other hand, when there is no risk of lightning strikes, the electric field concentration unit body 52 can be housed in the sheath 70 to minimize aerodynamic resistance. Therefore, it is possible to prevent a decrease in the flight performance of the electric aircraft 1 due to the installation of the fan electric field concentration unit 50. As a result, the electric aircraft 1 can be flown more stably and smoothly.

[0035] The fourth embodiment of this disclosure has been described above. It is possible to make various changes and modifications to the above configuration without departing from the gist of this disclosure. For example, the wire member 53 described in the third embodiment can be detachably attached to the deployed electric field concentration unit body 52. ​​In other words, it is possible to configure the wire member 53 to be removed before the electric field concentration unit body 52 is housed in the sheath 70. This configuration allows for both improved lightning resistance and improved aerodynamic performance due to the wire member 53, similar to the configuration described in the third embodiment. Therefore, the flight stability and efficiency of the electric aircraft 1 can be improved simultaneously.

[0036] <Note> The electric aircraft 1 described in each embodiment can be understood, for example, as follows:

[0037] (1) The electric aircraft 1 according to the first embodiment comprises an airframe 10, a plurality of structural frame members 20 provided on the airframe 10, fan motors 30 provided on each of the structural frame members 20, and an end field concentration section 40 provided at the end of the structural frame member 20, wherein the impedance of the structural frame member 20 is lower than the impedance of the fan motor 30.

[0038] According to the above configuration, since the impedance of the structural frame member 20 is lower than the impedance of the fan motor 30, when lightning strikes the electric aircraft 1, the current flows through the structural frame member 20 instead of the fan motor 30. This makes it possible to avoid damage to the fan motor 30 due to the lightning strike.

[0039] (2) The electric aircraft 1 according to the second embodiment is the electric aircraft 1 of (1), wherein the tip electric field concentration section 40 is movable back and forth between a state in which it is housed inside the structural frame member 20 and a state in which it is deployed.

[0040] According to the above configuration, when a lightning strike is expected, the tip electric field concentration section 40 can be deployed to preferentially concentrate the lightning strike on the tip electric field concentration section 40. On the other hand, when there is no risk of a lightning strike, the tip electric field concentration section 40 can be retracted to prevent a decrease in the flight performance of the electric aircraft 1.

[0041] (3) An electric aircraft 1 according to the third embodiment is an electric aircraft 1 according to (1) or (2), further comprising a fan electric field concentration section 50 provided on the fan motor 30, wherein the fan electric field concentration section 50 has a cylindrical portion 51 surrounding the fan motor 30 from the outer circumference and a plurality of electric field concentration section bodies 52 extending outward from the cylindrical portion 51, and the impedance of the fan electric field concentration section 50 is lower than the impedance of the fan motor 30.

[0042] According to the above configuration, the fan motor 30 is equipped with a fan electric field concentration section 50. As a result, if lightning strikes near the fan motor 30, the current flows to the fan electric field concentration section 50 rather than the fan motor 30 itself. This prevents damage to the fan motor 30 caused by the lightning strike current.

[0043] (4) The electric aircraft 1 according to the fourth embodiment is the electric aircraft 1 of (3), wherein the electric field concentration unit body 52 is movable back and forth between a state in which it is housed inside the sheath portion 70 provided in the cylindrical portion 51 and a state in which it is deployed.

[0044] According to the above configuration, when a lightning strike is expected, the electric field concentration unit body 52 can be deployed to preferentially concentrate the lightning strike on the electric field concentration unit body 52. ​​On the other hand, when there is no risk of a lightning strike, the electric field concentration unit body 52 can be retracted to prevent a decrease in the flight performance of the electric aircraft 1.

[0045] (5) The electric aircraft 1 according to the fifth embodiment is the electric aircraft 1 according to (3) or (4), further comprising a wire member 53 that connects the tip ends of the electric field concentration unit body 52.

[0046] According to the above configuration, the tips of the electric field concentration unit bodies 52 are connected by wire members 53. As a result, lightning strikes can be absorbed not only by the electric field concentration unit bodies 52 but also by the wire members 53 over an even wider area. Therefore, the possibility of lightning current flowing through the fan motor 30 can be further reduced.

[0047] (6) The electric aircraft 1 according to the sixth embodiment is the electric aircraft 1 according to (5), wherein the fan motor 30 has a propeller 31 that is rotatable about an axis O and a motor body that rotates the propeller 31, the cylindrical portion 51 is cylindrical with the axis O as its center, and the wire member 53 is annular with the axis O as its center.

[0048] According to the above configuration, the wire member 53 forms an annular shape centered on the axis O of the propeller 31. As a result, the wire member 53 can absorb lightning strikes over the entire circumferential area of ​​the axis O. Furthermore, since the wire member 53 does not obstruct the airflow path of the propeller 31, the thrust of the propeller 31 can be fully utilized.

[0049] (7) The electric aircraft 1 according to the seventh embodiment is the electric aircraft 1 according to (6), wherein the electric field concentration body 52 has a plurality of circumferential members 61 that extend radially outward from the cylindrical portion 51 and are arranged at intervals in the circumferential direction, and a plurality of axial members 62 that extend in a direction including the axial O direction component from the cylindrical portion 51 and are arranged at intervals in the circumferential direction, and a part of the wire member 53 connects the tip of the circumferential member 61 and the tip of the axial member 62.

[0050] According to the above configuration, the tip of the circumferential member 61 and the tip of the axial member 62 are connected by a portion of the wire member 53. As a result, the area protected by the wire member 53 is increased, making it possible to receive lightning strikes over a wider area and protect the fan motor 30. [Explanation of Symbols]

[0051] 1…Electric aircraft 10…Aircraft 20… Structural frame members 30... Fan motor 31…Propeller 40…Eye-tip electric field concentration section 50...Fan electric field concentration section 51...Cylindrical part 52... Main body of the electric field concentration section 53…Wire component 61...Circumferential member 62...Axial direction member 70...Sheath part O…Axis line

Claims

1. The aircraft and, Multiple structural frame members provided on the aircraft body, Each of the structural frame members is provided with a fan motor, A tip electric field concentration portion provided at the end of the structural frame member, Equipped with, The impedance of the structural frame member is lower than the impedance of the fan motor. The fan motor further comprises a fan electric field concentration section, The fan's electric field concentration section is, A cylindrical portion surrounds the aforementioned fan motor from the outer periphery, Multiple electric field concentration body parts extending outward from the cylindrical part, It has, An electric aircraft in which the impedance of the fan electric field concentration section is lower than the impedance of the fan motor.

2. The electric aircraft according to claim 1, wherein the tip electric field concentration section is movable between a state where it is housed inside the structural frame member and a state where it is deployed.

3. The electric aircraft according to claim 1, wherein the electric field concentration unit body is movable back and forth between a state in which it is housed inside the sheath provided in the cylindrical part and a state in which it is deployed.

4. The electric aircraft according to claim 1, further comprising a wire member for connecting the tip portions of the electric field concentration unit body.

5. The aforementioned fan motor is A propeller that can rotate around its axis, The motor body that rotates the propeller, It has, The electric aircraft according to claim 4, wherein the cylindrical portion is cylindrical with respect to the axis, and the wire member is annular with respect to the axis.

6. The electric field concentration section body comprises a plurality of circumferential members that extend radially outward from the cylindrical portion and are arranged at intervals in the circumferential direction, A plurality of axial members extending from the cylindrical portion in a direction including the axial component and arranged at intervals in the circumferential direction, It has, The electric aircraft according to claim 5, wherein a part of the wire member connects the tip of the circumferential member and the tip of the axial member.

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